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A non-slip constraint between a particle and a wall is applied at the microscopic level of collision dynamics using the rough sphere model. We analyze the consequences of the translation–rotation coupling of a rough sphere confined between two parallel planar walls and establish that shearing the walls past each other (i) preferentially deposits energy into the rotational degree of freedom and (ii) results in a bounded oscillation of the energy of the confined particle. [ABSTRACT FROM AUTHOR]

Hyper‐redundant manipulators have strong flexibility that benefits from their redundant limb structure. However, a large number of redundant degrees of freedom will also lead the solution of inverse kinematics much more difficult, which restricts their motion performance to some extent. Inspired by the FABRIK (Forward and Backward Reaching Inverse Kinematics) method, an improved inverse kinematics solution method for the hyper‐redundant manipulator is proposed. Based on the space vector method, the kinematic model of the manipulator is established to dynamically acquire its endpoint position, and the workspace is further obtained by using the Monte Carlo method. The original search method is optimized, the include angle decoupling mechanism between adjacent links is established to obtain the rotation angles of each joint, and the joint angle limitation is introduced to meet the actual manipulator structural restriction. On this basis, the pose constraint mechanism is established to realize the control of the end‐link pose, and the linear degree of freedom is introduced to realize the solution after the directional expansion of the manipulator's workspace. A series of simulation experiments are carried out. In the experiments, the position error of the manipulator's endpoint is always less than 10−6 mm. Meanwhile, the comparative experimental results show that compared with the original method, the proposed method exhibits higher position accuracy under the condition that the computation time is almost the same. In addition, in the end‐link pose constraint experiment and path motion experiments, the pose error of the end‐link is always less than 10−7°, indicating that the end‐link pose can also meet the high accuracy requirements under the premise of ensuring high position accuracy. Finally, the prototype experiment further verifies its performance. [ABSTRACT FROM AUTHOR]

Mobile manipulators require whole-body inverse kinematics (IK), encompassing both the mobile base and arm, to execute manipulation tasks. One of the challenges associated with whole-body IK is the redundancy of degrees of freedom when combining those of the mobile base and arm, which generates an infinite number of solutions. Therefore, in this study, we focus on the trend in mobile manipulators where the positional precision of the mobile base is lower than that of the manipulator. We propose a definition for the robustness value to base position control error and discuss a methodology to quickly obtain robust whole-body IK solutions. In an assessment utilizing a dataset that simulates domestic environments and a human support robot, which is a research platform for mobile manipulators designed to operate with humans, we validated that the quick acquisition of IK solutions robust to base position control error is achievable. In addition, we integrated the proposed IK approach into motion planning and evaluated its performance. Our results revealed that motion planning integrated with the proposed IK approach was superior to conventional methods in terms of both computation time and robustness for base position control error. [ABSTRACT FROM AUTHOR]

The use of both hands is a common practice in everyday life. The capacity to interact with the environment is largely dependent on the ability to use both hands. A thorough review of the current state of the art reveals that commercially available prosthetic hands designed for children are very different in functionality from those developed for adults, primarily due to prosthetic hands for adults featuring a greater number of actuated joints. Many times, patients stop using their prosthetic device because they feel that it does not fit well in terms of shape and size. With the idea of solving these problems, the design of HandBot-Kid has been developed with the anthropomorphic qualities of a child between the ages of eight and twelve in mind. Fitting the features of this age range, the robotic hand has a length of 16 cm, width of 7 cm, thickness of 3.6 cm, and weight of 328 g. The prosthesis is equipped with a total of fifteen degrees of freedom (DOF), with three DOFs allocated to each finger. The concept of design for manufacturing and assembly (DFMA) has been integrated into the development process, enabling the number of parts to be optimized in order to reduce the production time and cost. The utilization of 3D printing technology in conjunction with aluminum machining enabled the manufacturing process of the robotic hand prototype to be streamlined. The flexion–extension movement of each finger exhibits a trajectory that is highly similar to that of a real human finger. The four-bar mechanism integrated into the finger design achieves a mechanical advantage (MA) of 40.33% and a fingertip pressure force of 10.23 N. Finally, HandBot-Kid was subjected to a series of studies and taxonomical tests, including Cutkosky (16 points) and Kapandji (4 points) score tests, and the functional results were compared with some commercial solutions for children mentioned in the state of the art. [ABSTRACT FROM AUTHOR]

In the realm of ankle rehabilitation, a novel 2-UPS/RRR parallel ankle rehabilitation robot (ARR) was introduced, taking into consideration the strengths and weaknesses of existing ankle rehabilitation robot models. The design process involved creating a 3D model of the mechanism using Solidworks software, and developing a movable platform with an adjustable rotation center to accommodate varying ankle rotation centers among patients. The degrees of freedom (DOF) were determined utilizing the Kutzbach-Grübler formula. Geometric relationships were employed to derive kinematic inverse solution equations for the mechanism, which were subsequently validated through simulation and analysis using Matlab and Adams software. Displacement and velocity change profiles of the mechanism were generated through Adams software, the curve trend clearly indicates that the ankle rehabilitation mechanism exhibits smooth movement and demonstrates excellent kinematic performance. Furthermore, the impact of rehabilitation training on muscle strength and muscle activity in ankle-related muscles was assessed through biomechanical simulation software, specifically the AnyBody Modeling System, revealing effective training and rehabilitation outcomes for the pertinent muscles surrounding the ankle joint. Overall, the findings of this study suggest that the developed ankle rehabilitation robot is capable of fulfilling ankle rehabilitation duties and holds substantial practical significance. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models. [ABSTRACT FROM AUTHOR]

Focusing on large moment of inertia of Stewart-Gough platform, a novel 6-PUS parallel robot driven by piezoelectric linear actuators is proposed, which installs actuators on the static platform and the equivalent spherical hinge is applied, the accuracy has been further improved. First, we have established the proposed robot's kinematic and dynamic models. Besides, the singularity is analyzed by combining genetic algorithm with bisection method, which can successfully detect all singular points and limit them to small intervals in multi-DOF (degree of freedom) motion. Finally, we have verified the validity of models and feasibility of the method for singularity analysis. The errors between simulation results in Adams and theoretical models in Matlab/Simulink are less than 0.1 %. This paper offers theoretical bases for parametric modeling and singularity analysis of related 6-DOF parallel robots. [ABSTRACT FROM AUTHOR]

Loss of hand functions, often manifesting in the form of weakness or spasticity from conditions like stroke or multiple sclerosis, poses challenges in performing activities of daily living (ADLs). The broad area of rehabilitation robotics provides the tools and knowledge necessary for implementing efficient restorative therapies. These therapies aim to improve hand functionality with minimal therapist intervention. However, the human hand evolved for various precision and power gripping tasks, with its intricate anatomy featuring a large number of degrees of freedom—up to 31—which hinder its modeling in many rehabilitation scenarios. In the process of designing prosthetic devices, instrumented gloves, and rehabilitation devices, there is a clear need to obtain simplified rehabilitation-oriented hand models without compromising their representativeness across the population. This is where the concept of kinematic reduction, focusing on specific grasps, becomes essential. Thus, the objective of this study is to uncover the intra-finger dependencies during finger flexion/extension by analyzing a comprehensive database containing recorded trajectories for 23 different functional movements related to ADLs, involving 77 test subjects. The initial phase involves data wrangling, followed by correlation analysis aimed at selecting 116 dependency-movement relationships across all grasps. A regularized generalized linear model is then applied to select uncorrelated predictors, while a linear mixed-effect model, with reductions based on both predictor significance and effect size, is used for modeling the dependencies. As a final step, agglomerative clustering of models is performed to further facilitate flexibility in tradeoffs in hand model accuracy/reduction, allowing the modeling of finger flexion extensions using 5–15 degrees of freedom only. [ABSTRACT FROM AUTHOR]

In this paper, two new parallel mechanisms (PMs) with fewer active inputs than the degrees of freedom (DOFs)are proposed: (i) an nSPS (n = 7, 8, 9) six‐DOF PM with n‐6 active inputs and six lockable joints. and (ii) a 3RPS‐SPS 3‐DOF PM with one active input and three lockable joints. Compared with the traditional PMs, the difference is that the proposed PMs can achieve the same mobility by using a minimal number of active joints. Moreover, the load‐carrying capacity is also improved compared with the original standard mechanisms, since the new PMs become statically redundant when all the branches are locked. For this purpose, a sequential motion control principle is introduced that requires both inverse and forward kinematics of PMs. Kinematic modeling, dimensional optimization, and structural design are carried out for the 7SPS and 3RPS‐SPS mechanisms, and the two prototypes are constructed for experimental validation. Both simulation and experiment results have shown that the proposed hybrid PM can achieve the original mobility while significantly reducing the number of actuators. [ABSTRACT FROM AUTHOR]

The human jaw is a complex biomechanical system involving different anatomical components and an articulated muscular system devoted to its dynamical activation. The numerous actions exerted by the mandible, such as talking, eating or chewing, make its biomechanical comprehension absolutely indispensable. To date, even if research on this topic has achieved interesting outcomes using in vitro testing, thanks to the development of new apparatus and methods capable of performing more and more realistic experiments, theoretical modeling is still worthy of investigation. In light of this, nowadays, the Finite Element Method (FEM) approach constitutes certainly the most common tool adopted to investigate particular issues concerning stress–strain characterization of the human jaw. In addition, kinematics analyses, both direct and inverse, are also diffuse and reported in the literature. This manuscript aimed to propose a critical review of the most recurrent biomechanical models of the human mandible to give readers a comprehensive overview on the topic. In light of this, the numerical approaches, providing interesting outcomes, such as muscular activation profiles, condylar forces and stress–strain fields for the human oral cavity, are mainly differentiated between according to the joint degrees of freedom, the analytical descriptions of the muscular forces, the boundary conditions imposed, the kind of task and mandible anatomical structure modeling. [ABSTRACT FROM AUTHOR]

As research on parallel mechanisms with limited degrees of freedom (DOF) continues to grow, this paper introduces a novel 2UPU-2SPU parallel mechanism that features 2 Rotational and 2 Translational (2R2T) motion capabilities. The SPU branches are symmetrically positioned relative to the plane of the 2UPU branches, endowing the mechanism with a full-circle DOF that encompasses two rotations and two translations. One of the rotational DOF influences the characteristics of a constrained rotational freedom. This study conducts a kinematic analysis using screw theory to elucidate the DOF and derives the inverse kinematics of the mechanism. Furthermore, by employing motion/force transmission performance indicators and performance maps, the mechanical performance characteristics are analyzed. A mathematical model for optimizing mechanical performance using the Particle Swarm Optimization (PSO) algorithm is established, facilitating the design of specific mechanical devices. The mechanism boasts a large workspace, with the operational space varying as the moving platform rotates, making it suitable for applications requiring minimal rotational and lateral movements but significant longitudinal displacement. [ABSTRACT FROM AUTHOR]

Optical payloads are widely used in many fields, such as aerospace, drones, autonomous vehicles, or other highly precise instrumentation. Vibration is one of the causes that greatly affect the quality of data of highly precise optical payloads. Recently, many researcher focuses on isolating the vibration for the precise equipment, those study just only mention the overcoming of vibration in one or two directions, but in reality, an object will exist vibration in six directions in space. Therefore, it is necessary to find a new mechanism that can isolate vibration in six axes in space. The parallel mechanism is considered a viable system because of its strengths in accuracy, rigidity, and stability. In this research, the author proposes a novel 6-DOF passive vibration isolator based on the Steward platform with S-shaped legs. We have developed a 6-DOF passive vibration isolator using the S-shaped non-linear stiffness and damping characteristics. In this study, the model parameters of a vibration isolator device with legs using an S-shaped will be proposed. Based on geometrical parameters and vibration sources and some loads assuming the structure's durability problem will be calculated and evaluated the efficiency of the isolator at different frequencies. With the specially designed S-shaped it can be deformity like a spring, and with the change of structural and material parameters, we can adjust the system's stiffness and damping capacity. Due to the high static stiffness and low dynamic stiffness of each leg, and thus it is designable to isolate very well vibration isolation performance in all six directions. This research is organized as firstly the kinematics and 3D model are introduced. Secondly, the stiffness matrix of the novel 6-DOF passive vibration isolators is presented. Statics analysis of the 6-DOF passive vibration isolators revealed that the S-shaped structure provides sufficient load-carrying capacity and isolation due to its very good static nonlinear stiffness. The dynamic stiffness of the isolator in this study in each direction is very low but does not reduce the load-carrying capacity of the structure. By changing the structure and material parameters (which is very simple in a purely passive manner), we can completely adjust both the dynamic and static stiffness of the mechanism. The last series of numerical simulation results on displacement and a statics response in random excitation is carried out to show the effectiveness of the proposed 6-DOF passive vibration isolator, as well as the influence of structural parameters on vibration attenuation performance. The simulation results with the different exciting are shown to demonstrate the efficiency of the 6-DOF passive vibration isolators. Considering its simulation results A proposed new 6-DOF isolator will be applied in various engineering practices with multi-degree of freedom vibration isolation such as for precise optical payloa [ABSTRACT FROM AUTHOR]

Purpose: Inertial amplification of an oscillating mass has been considered by various researchers as a means to introduce enhanced vibration control properties to a dynamic system. In this paper an experimental prototype of a novel inertial amplifier, namely the Dynamic Directional Amplification mechanism (DDA), is developed and its dynamic response is subsequently evaluated. The DDA is realized by imposing kinematic constraints to the degrees of freedom (DoFs) of a simple oscillator, hence inertia is increased by coupling the horizontal and vertical motion of the model. Methods: The concept and mathematical framework of the amplifier are introduced and then validated with experimental measurements conducted on the vertical shaking table, located in the Dynamics & Acoustics Laboratory, National Technical University of Athens. Results: Analysis indicates the beneficial effect of the DDA to the dynamic response of the oscillator when compared to the initial structure, showcasing a decrease in the acceleration values and shift of the resonating frequency in the derived transfer functions. Conclusions: The key novelty of the DDA lies in its inertial amplification properties, introduced by a simple geometry and easy-to-apply structure. The proposed framework may be incorporated in applications such as sound and vibration isolators, acoustic panels, acoustic and seismic metamaterials and other vibration control devices that aim to explore the DDA's dynamic amplification properties. The mechanism has been previously applied by the authors to phononic and locally resonant metamaterials aiming to introduce bandgaps within the low-frequency domain. [ABSTRACT FROM AUTHOR]

A four-level rigid trunk mechanism based on 4-SPS/U, with SPS as the driving branch and U pair as the middle constrained driven branch, is innovatively proposed in this paper. Based on the innovative design of this trunk mechanism, it can improve the flexibility of the hexapod mobile robot's posture adjustment and changes in various motion modes such as walking, water propulsion, climbing and rolling. Firstly, the screw theory is adopted to calculate the degree of freedom of the trunk mechanism. Secondly, a combination of closed vector method and the characteristic structure configuration decoupling method has been applied to constructing the inverse kinematics solution, and deriving the velocity and acceleration models as well as analyzing the high posture flexibility in workspace of the trunk mechanism. Thirdly, theoretical simulation data diagram of the movement branch chain displacement, end height, speed and acceleration of the trunk mechanism are calculated through theoretical numerical examples, and the excellent motion characteristics of the 4-SPS/U-based four-level rigid trunk mechanism are analyzed. Finally, a quantitative comparison was made between the theoretical simulation data and the experimental data of the experimental prototype. The error rates of the variation curves of the displacement length, height, velocity and acceleration of the driving branch chain were 0.8%, 0.2%, 0.5% and 0.9%, which verified the correctness and reliability of the theoretical derivation. [ABSTRACT FROM AUTHOR]

A novel 3-PSS/7R spatial hybrid redundantly driven mechanism (HRDM) is proposed. The mechanism is driven by constant velocity (CV) motor and servo motor at the same time. The CV motor provides the main power for the system, and the servo motor plays the role of motion regulation. This system not only has the advantages of the traditional mechanical system, such as stable operation, large bearing capacity, but also can output controllable and adjustable flexible trajectory. The degrees of freedom of the mechanism are determined by the middle limb, which is called hybrid redundantly driven limb, which is driven by both CV motor and servo motor. Based on closed vector method, the position equation of the mechanism is established, and the velocity mapping matrix and acceleration change laws of the mechanism are obtained. Further, the necessary and sufficient conditions for the mechanism to realize continuous trajectory and the relationship of rod constraints are obtained. The correctness of the kinematics equation and the smooth and controllable operation of the mechanism are verified by examples. The research results of this paper lay a foundation for the in-depth research and application expansion of spatial hybrid redundantly driven mechanism. [ABSTRACT FROM AUTHOR]

Modern medical implants are characterized by non-circular shapes, which is often challenging for economic production. Non-Circular-Rotary-Turning (NCRT) is a newly developed process for manufacturing non-circular cross-sections at high productivity and a high degree of geometric freedom. In this work, the basic process kinematics of NCRT are presented. A process design method is proposed and validated. The fundamental cutting conditions are examined using simulation and the cutting forces are studied experimentally. In an example of application, NCRT enables to reduce machining time by a factor of more than ten compared to a conventional process chain, resulting even in better surface quality. [ABSTRACT FROM AUTHOR]

Laparoscopic manipulation of delicate large intra-abdominal organs is a difficult task that needs special training programs to improve the surgeons' dexterity. In this study, the mechanical design of a robotic interface for haptic simulation of largeorgan laparoscopic surgery is described. The designed robot enjoys active active Degree of Freedoms (DOFs), back drivability, low inertia, friction and backlash, and sufficiently large force/moment production capacity. The kinematics of the robot was analyzed and a functional prototype was fabricated for experimental tests. Results indicated that the target workspace was fully covered with no singular points inside. The mechanism was highly isotropic and the torque requirements were in the acceptable range. The trajectory tracking experiments against a 1 kg payload revealed an Root Mean Square (RMS) of 0.9 mm, due to the simplifications of the kinematic model, i.e., not considering the friction and backlash effects. It was concluded that the designed robot could satisfy the mechanical requirements for being used as the robotic interface in a haptic large-organ laparoscopic surgery simulation system. [ABSTRACT FROM AUTHOR]

Copyright of Visión Electrónica is the property of Fondo de Universidad Distrital Francisco Jose de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a geometric approach to solve the inverse kinematics for an anthropomorphic robotic arm with seven degrees of freedom (DoF). The proposal is based on conformal geometric algebra (CGA), by which many geometric primitives can be operated naturally and directly. CGA allows for the intersection of geometric entities such as two or more spheres or a plane's projection over a sphere. Rigid transformations of such geometric entities are performed using only one operation through another geometric entity called a motor. CGA imposes geometric restrictions on the inverse kinematics solution, which avoids computation of the forward kinematics or other numerical solutions, unlike traditional approaches. Comparisons with state-of-the-art algorithms are included to prove our algorithm's superior performance: such as decreased execution time and errors of the end-effector for a series of desired poses. [ABSTRACT FROM AUTHOR]

Insects use their mandibles for a variety of tasks, including food processing, material transport, nest building, brood care, and fighting. Despite this functional diversity, mandible motion is typically thought to be constrained to rotation about a single fixed axis. Here, we conduct a direct quantitative test of this 'hinge joint hypothesis' in a species that uses its mandibles for a wide range of tasks: Atta vollenweideri leaf-cutter ants. Mandible movements from live restrained ants were reconstructed in three dimensions using a multi-camera rig. Rigid body kinematic analyses revealed strong evidence that mandible movement occupies a kinematic space that requires more than one rotational degree of freedom: at large opening angles, mandible motion is dominated by yaw. But at small opening angles, mandibles both yaw and pitch. The combination of yaw and pitch allows mandibles to 'criss-cross': either mandible can be on top when mandibles are closed. We observed criss-crossing in freely cutting ants, suggesting that it is functionally important. Combined with recent reports on the diversity of joint articulations in other insects, our results show that insect mandible kinematics are more diverse than traditionally assumed, and thus worthy of further detailed investigation. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'. [ABSTRACT FROM AUTHOR]

In the present contribution, the FE2 scheme for beam elements is extended to thermomechanically coupled problems. Beam elements have the advantage of drastically reducing the number of degrees of freedom compared to solid elements. However, the major challenge in modeling structures with beam elements lies in developing sophisticated non‐linear beam material models. This drawback resides in the fact that these elements require effective cross‐sectional properties involving material and geometric properties. The FE2 method, combined with a homogenization scheme based on the Hill‐Mandel condition, solves this problem. Within this scheme, homogenization of a representative volume element (RVE) on the mesoscopic scale provides effective cross‐sectional properties for the macroscopic scale. This homogenization procedure allows the consideration of non‐linear material formulations and cross‐sectional deformation within the analysis of a beam structure. The applicability of such a FE2 scheme for purely mechanical problems was already shown. In the present contribution, an extension to thermomechanically coupled problems is provided. In the proposed setting, the macroscopic scale is represented by beam elements with displacement, rotation, and temperature degrees of freedom. Solid elements with displacements and temperature degrees of freedom describe the behavior of the RVE. Hence, the proposed extension solves both scales in a monolithic approach. The assumption of a steady state problem at both scales allows a focus on a consistent scale transition and a discussion about the choice of suitable boundary conditions under the assumption of beam kinematics. [ABSTRACT FROM AUTHOR]

Early detection and treatment of intraluminal diseases enable minimally invasive surgery and can lead to a high cure rate. Advanced devices with multiple degrees of freedom (DOFs) make narrow intraluminal procedures easier and safer. In a previous study, we developed a multi-DOF compliant endoluminal forceps with a tendon-sheath mechanism. The maximum bending stress of this design was reduced by changing the thickness of a compliant hinge in each segment, and the forceps achieved a wide range of motion. However, its deformed shapes with a non-constant curvature, due to a compliant inhomogeneous-thickness hinge structure, hinder fine manipulation in a narrow lumen. Here, we construct an accurate model of this compliant inhomogeneous-thickness hinge structure using pseudo-rigid-body model. In the proposed method, each compliant hinge is represented by a torsion spring and rotational joint, and the deformed shape is estimated from the bending angle caused by the tensile force. We derive the coefficient of dynamic friction by considering the friction between the wire and compliant joint based on a belt friction model. These novel calculations allow to consider individual differences in material properties and surface roughness. We experimentally confirm the feasibility of constructing a highly accurate model with a lower calculation cost than the finite element method. Our proposal seems suitable for developing dexterous forceps and other endoluminal devices, such as catheters, which mitigate operation errors and help approach lesions in narrow lumens. [ABSTRACT FROM AUTHOR]

The human hand, with many degrees of freedom, serves as an excellent tool for dexterous manipulation. Previous research has demonstrated that there exists a lower-dimensional subspace that synergistically controls the full hand kinematics. The elements of this subspace, also called synergies, have been viewed as the strategy developed by the CNS in the control of finger movements. Considering that the control of fingers is lateralized to the contralateral hemisphere, how the synergies differ for the control of the dominant and the non-dominant hand has not been widely addressed. In this paper, hand kinematics was recorded using electromagnetic tracking system sensors as participants made various postures and object grasps with their dominant hand and non-dominant hand separately. Synergies that explain 90% of variance in data of both hands were analyzed for similarity at the individual level as well as at the population level. The results showed no differences in synergies between the hands at both these levels. PC scores and cross-reconstruction errors were analyzed to further support the prevalence of similarity between the synergies of the hands. Future work is proposed, and implications of the results to the treatment and diagnosis of neuromotor disorders are discussed. [ABSTRACT FROM AUTHOR]

Cable‐driven parallel robots (CDPRs) are parallel robots in which cables are used instead of rigid connecting elements. An important task here, as in other areas of robotics, are kinematic calculations. The state of the CDPR can be described either in Cartesian workspace coordinates as a pose or in the joint space via the cable lengths. The calculation of the cable lengths from a given platform pose is relatively simple for CDPRs. In contrast, the forward kinematics, that is, the calculation of the pose from the cable lengths, is complex due to the parallel topology and often cannot be solved analytically. In addition, CDPR systems are often designed redundantly, with more cables than Cartesian degrees of freedom. This redundancy causes that the solution of the forward kinematics can be considered as a fitting problem, where for measured cable lengths, the solution with minimum error norm is sought. In this paper, an approach based on the Gauss–Newton method is presented. It is described how a computationally efficient implementation is possible when using quaternions under consideration of the unit quaternion constraints. [ABSTRACT FROM AUTHOR]

A novel 5-DOF (5-SPS)+5R2U hybrid redundantly driven mechanism (HRDM for short) is proposed, which can realize 3 translations and 2 rotations (3T2R) movements. (5-SPS)+5R2U parallel mechanism is composed of six driving limbs. Of which 5-SPS (S represents spherical pair, P represents prismatic pair) limbs are symmetrically distributed at the center point of static and moving platform have no restriction on the degrees of freedom of the mechanism. The middle limb (7R)U (R represents revolute pair, U represents Hooke joint) is connected to the static platform and the center point of the moving platform. It is jointly driven by constant velocity motor and servo motor, and plays a role of restraining the freedom of the whole mechanism. It is called hybrid redundantly driven limb (HRDL for short). Hybrid-driven mechanism and redundantly actuated mechanism can be integrated into one mechanism by HRDL, which can give full play to the advantages of both. The inverse position solution model of the mechanism is established, and the velocity Jacobian matrix and acceleration expression are derived to obtain the velocity and acceleration variation laws of the mechanism. On this basis, the factors affecting the workspace are analyzed, and the workspace atlas under different orientation angles is obtained. The results provide theoretical model for the realization planning trajectory of (5-SPS)+5R2U HRDM. [ABSTRACT FROM AUTHOR]

A novel parallel rotor of the helicopter is designed by combining a 2 P SS+ P SR+SP+ R UPUR-type parallel manipulator with a rotor of the helicopter. Its kinematics and dynamics models are established. Firstly, the structure principle and the merit performances of the parallel rotor are explained by comparing with conventional and existing rotors of the helicopter, and the degree of freedom of the parallel manipulator is calculated. Secondly, the kinematics formulas are derived for solving the displacement, Jacobian matrix, general velocity, Hessian matrix, and acceleration of the parallel rotor and the kinematic limbs. Thirdly, a dynamics model of the parallel rotor is established based on the derived kinematics formulas. Finally, the theoretical kinematics and dynamics solutions are verified by a simulation mechanism of the parallel rotor of the helicopter. [ABSTRACT FROM AUTHOR]

Snake-like robots, which have high degrees of freedom and flexibility, can effectively perform an obstacle avoidance motion in a narrow and unstructured space to complete assignments efficiently. However, accurate closed-loop control is difficult to achieve. On the one hand, this is because adding too many sensors to the robot will significantly increase its mass, size, and cost. On the other hand, the more complex structure of the hyper-redundant robot also challenges the more elaborate closed-loop control strategy. For these reasons, a cable-driven snake-like robot, which is compact and low cost, with force transducers and angle sensors, is designed in this article. The simpler and more direct kinematic model is studied, which applies to a widely used kinematics algorithm. Based on the kinematic model, the inverse dynamics are resolved. Finally, this article analyzes the sources of the motion errors and achieves dual-loop control through force-feedback and pose-feedback. The experiment results show that the robot's structure and dual-loop control strategy function with high accuracy and reliability, meeting the requirements of engineering applications and high-precision control. [ABSTRACT FROM AUTHOR]

Most of the kinematic calibration methods of parallel mechanisms only consider the geometric error of the mechanism, and the calibration effect is poor. To improve the calibration effect, this paper takes the 3-PTT (3-prismatic hook hook) parallel mechanism as the research object and proposes a kinematics calibration method based on the normalized representation model of the geometric error and non-geometric error of the mechanism. First, the degree of freedom of the mechanism is analyzed, its kinematics positive and negative solutions are solved, and its singularity is analyzed. Secondly, a normalized characterization method of mechanism geometric errors and non-geometric errors is proposed, and an error model without redundant parameters is constructed. The end motion error of the machine is measured by laser tracker, and the objective function is constructed. The genetic algorithm is designed to solve the minimum value of the objective function, and the normalized error of the mechanism is identified. By comparing with the recent methods, the better identification performance of the algorithm in this paper is verified. Finally, the kinematics model was corrected according to the identification results. After the calibration was completed, the movement errors of the end of the mechanism along each coordinate axis were reduced by more than 99 %. Compared with other calibration methods, the better calibration performance of the method in this paper is verified. [ABSTRACT FROM AUTHOR]

Objective: The scaphoid is proposed to be driven by the distal carpal row in scapholunate instability (SLI) as it is dissociated from the proximal row. The aim of this study was to describe the 6 degrees of freedom kinematics of the scaphoid using dynamic CT in the normal and SLI wrists. We hypothesised that the SLI scaphoid would demonstrate kinematic evidence conforming to distal row motion. Materials and methods: We studied dynamic CT scans of 17 SLI and 17 normal wrists during ulnar to radial deviation and extension to flexion. The radio-scaphoid angles in three anatomic planes were calculated in the wrist neutral position and during wrist motion. The centroid position was also calculated in the wrist neutral position and during wrist motion. The scapho-capitate motion index (SCI) was calculated as a ratio between the scaphoid and the capitate motion. Results: In the neutral position of the wrist, the SLI scaphoid was flexed, internally rotated, and radially translated compared to the normal scaphoid. During wrist motion, the SLI scaphoid had more 'in-plane' motion and less 'out-of-plane' motion with a higher SCI during wrist neutral to radial deviation and extension to neutral. Conclusion: We have described the malalignment of the SLI scaphoid in the neutral position of the wrist and 6 degrees of freedom kinematics during wrist motion of the SLI scaphoid compared to the normal. The SLI scaphoid conformed more to the distal row motion than the normal scaphoid. This information may help define the surgical reconstruction techniques for SLI. [ABSTRACT FROM AUTHOR]

In this paper, a two-rotational degrees of freedom parallel mechanism with five kinematic subchains (3UPS-UPU-S) (U, P, and S stand for universal joints, prismatic joints, and spherical joints) for an aerospace product is introduced, and its kinematic and dynamic characteristics are subsequently analyzed. The kinematic and dynamic analyses of this mechanism are carried out in screw coordinates. Firstly, the inverse kinematics is performed through the kinematic equations established by the velocity screws of each joint to obtain the position, posture, and velocity of each joint within the mechanism. Then, a dynamic modeling method with screw theory for multi-body systems is proposed. In this method, the momentum screws are established by the momentum and moment of momentum according to the fundamentals of screws. By using the kinematic parameters of joints, the dynamic analysis can be carried out through the dynamic equations formed by momentum screws and force screws. This method unifies the kinematic and dynamic analyses by expressing all parameters in screw form. The approach can be employed in the development of computational dynamics because of its simplified and straightforward analysis procedure and its high adaptability for different kinds of multi-body systems. [ABSTRACT FROM AUTHOR]

We give a geometric interpretation for the principle of stationary action in classical Lagrangian particle mechanics. In a nutshell, the difference of the action along a path and its variation effectively "counts" the possible evolutions that "go through" the area enclosed. If the path corresponds to a possible evolution, all neighbouring evolutions will be parallel, making them tangent to the area enclosed by the path and its variation, thus yielding a stationary action. This treatment gives a full physical account of the geometry of both Hamiltonian and Lagrangian mechanics which is founded on three assumptions: determinism and reversible evolution, independence of the degrees of freedom and equivalence between kinematics and dynamics. The logical equivalence between the three assumptions and the principle of stationary action leads to a much cleaner conceptual understanding. [ABSTRACT FROM AUTHOR]

In soft robotics, the ability to generate advanced kinematics is a necessary step toward any more sophisticated tasks such as microobject manipulation, locomotion, or configuration changes. To this end, herein, a modular voxel‐based methodology adaptable to any scale and with any soft transducer is presented. The methodology is implemented at the micrometer scale with a one‐step fabrication process. An innovative gray‐tone lithography method using the two‐photon polymerization of photosensitive poly(N‐isopropylacrylamide) hydrogel is developed to print the voxels. Bending, compression, and twisting voxels are designed, printed, and characterized. A voxel consists of an isotropically shrinking active material reinforced adequately with a passive pattern. Each elementary voxel deforms along one degree of freedom and is a building block for superstructures able of advanced kinematics. With a side length of 40 μm, the bending voxel achieves a bending angle of 25º or curvature of 10 mm−1. The compression voxel reaches an actuation strain of 40%, and the twisting voxel bends up to 18º. Advanced kinematics are demonstrated by printing complex structures composed of multiple elementary voxels. Herein, a foundation toward soft microrobots capable of performing complex tasks is constituted. [ABSTRACT FROM AUTHOR]

In this paper, a spatial cable-driven parallel mechanism in a V-shaped cable arrangement is proposed. It is further simplified as a planar hybrid cable-driven parallel mechanism to analyze its kinematics, which consists of two identical active cable chains and a passive cross-slide mechanism. In order to investigate the degrees of freedom (DoFs) of the hybrid mechanism using screw theory, cable chains are represented as rotational–prismatic–rotational (RPR) chains. The motion pairs of all the chains are denoted according to screw theory. Firstly, the number and the types of DoFs of each chain are determined. Then, the number and the types of DoFs for the hybrid mechanism are calculated. Furthermore, the theoretical result is verified using the modified Grübler–Kutzbach (G-K) formula. It shows that the unique DoF of the equivalent mechanism is a rotation with a continuously changing axis, which is consistent with the V-type cable-driven mechanism with elliptical trajectories. Finally, the kinematics analysis of the cross-slider mechanism driven by two cables is carried out. The length, velocity and acceleration of the cables are obtained from numerical calculation in MATLAB, and the results are demonstrated using ADAMS simulation. [ABSTRACT FROM AUTHOR]

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The space cable-driven continuous manipulator (SCCM) has a slender structure, ultra-high degrees of freedom, and a low mass, which make it suitable for equipment inspection and maintenance operations in an unstructured and limited space environment. In this paper, the SCCM including the cable network and plenty of joint links was deeply modeled. Firstly, the mapping relationship between the cable-driving space, joint space, and task space of the SCCM was studied, and the complete kinematic relationship of the SCCM was established. Secondly, the stiffness components of the SCCM are discussed, and the stiffness modeling method of each part is given. Finally, the Cartesian space equivalent stiffness model of the end was established. Then, a dynamic co-modeling method of Matlab + Adams is proposed, which greatly improved the modeling efficiency while ensuring the modeling accuracy. Finally, based on the stiffness model, the end stiffness characteristics of a specific configuration were analyzed, and the influence of the cable tension on the stiffness and frequency of the manipulator was analyzed. Based on the dynamic co-modeling, the task trajectory dynamics' simulation analysis and space slit crossing experiment were carried out, which verified that the designed SCCM can meet the needs of slit crossing. [ABSTRACT FROM AUTHOR]

This paper presents a four-fingered robotic hand, designed to carry out grasping operations along with different object manipulation tasks. The design of this hand resembles a human hand which is the perfect dexterous robotic gripper. In this paper, the forward kinematics of the designed hand is carried out using the Denavit-Hartenberg (D-H) parameters, to calculate the position and orientation of each of the fingertips. Inverse kinematics of the hand is formulated to compute the different joint angles for different fingertip configurations. Kinematic simulations are realised to estimate the workspace of the four finger robotic hand using the MATLAB interface. All possible fingertip trajectories are plotted in joint space to determine the motion constraints of the developed hand model. The results obtained confirm that the hand is suitable for grasping objects of variable geometry and materials within its workspace. The motion of the fingers is flexible enough for different object manipulation. These analysis shows that this hand is capable to perform the desired tasks successfully. [ABSTRACT FROM AUTHOR]

Modeling and kinematic analysis are crucial jobs in robotics that entail identifying the position of the robot's joints in order to accomplish particular tasks. This article uses an algebraic approach to model the kinematics of a serial link, 5 degrees of freedom (DOF) manipulator. The analytical method is compared to an optimization strategy known as sequential least squares programming (SLSQP). Using an Intel RealSense 3D camera, the colored object is picked up and placed using vision-based technology, and the pixel location of the object is translated into robot coordinates. The LOBOT LX15D serial bus servo controller was used to transmit these coordinates to the robotic arm. Python3 programming language was used throughout the entire analysis. The findings demonstrated that both analytical and optimized inverse kinematic solutions correctly identified colored objects and positioned them in their appropriate goal points. [ABSTRACT FROM AUTHOR]

In this paper, a parallel mechanism with two rotational degrees of freedom is proposed. It could rotate freely and continuously around the two coordinate axes at the fixed origin of the coordinate frame. The structure of the mechanism is a second-order over constraint parallel structure and the moving platform and base platform are connected by five kinematic chains. The motion characteristics of this structure are analyzed by reciprocal screw equation. Then, the kinematics and dynamics modelling are carried out systematically in a unified way. The kinematics of the mechanism is established by means of screws, the displacements and accelerations of each joint and any point on a link could be calculated by the kinematic screw equation directly. The analysis of acceleration and its mathematical expression in screw form are given, and the acceleration matrix could be applied into the dynamic analysis based on the Newton–Euler equation. All the constraint forces and torques could be obtained by a single set of Newton–Euler equations. [ABSTRACT FROM AUTHOR]

The Sublaminate Generalized Unified Formulation (SGUF) is extended for the first time to the framework of Finite Element Method (FEM) for both displacement-based and mixed (RMVT) formulation. The variable kinematics approach allows to choose different plate models according to the desired level of accuracy. Furthermore, the mixed ESL/LW approach of SGUF makes the model particularly convenient for sandwich structures analysis. A substitute interpolation for the first-order transverse shear strain field, referred to as QC4 interpolation, makes the developed four-node FE locking free and insensitive to mesh distortion. The complete expression of finite element matrices for the PVD-based and RMVT-based elements is provided. The possibility of exactly satisfying transverse stress boundary conditions for RMVT-based elements is also investigated for the first time. The flexibility and accuracy of the computational approach is demonstrated on linear static problems of sandwich plates and beams ranging from global bending response to local indentation problems. In particular, it is demonstrated that the proposed approach is capable of recovering full three-dimensional response with a 2D FE mesh and with less degrees of freedom than the conventional models available in commercial FE packages. [ABSTRACT FROM AUTHOR]

The present work aims at exploring the capabilities of Convolutional Neural Networks (CNN) to identify the most influential generalized variables in 2 D formulations for plates and shells. The outcome of CNN is the Best Theory Diagram (BTD), a graphical representation of the dependency between the model's accuracy and nodal degrees of freedom (DOF). The networks are trained with data derived from Finite Element (FE) computations and samples of reduced theories obtained as combinations of a given set of generalized displacement variables. Such samples are obtained through the Carrera Unified Formulation (CUF), a generalized approach to generating the governing equations for any structural model. Furthermore, the Node-Dependent Kinematics (NDK) included local refinements to lead to Best Theory Distributions of structural theories over an FE mesh, that is, identifying areas of a shell in which higher-order models are most necessary. The training data can refer to different analyses, e.g., static or free-vibration, whereas the network's input can include multiple structural parameters together with a sequence of expansion terms or theory distributions. The numerical results highlight a significant computational efficiency of CNN and its ability to identify the best models even for problem configurations not included in the training set. [ABSTRACT FROM AUTHOR]

In this study, a feasible swarm intelligence algorithm is proposed that computes the inverse kinematics solution of 6 degree of freedom (DOF) industrial robot arms, which are frequently used in industrial and medical applications. The proposed algorithm is named as Boomerang algorithm due to its recursive structure. The proposed algorithm aims to reduce the computation time to feasible levels without increasing the position and orientation errors. In order to reduce the computational time in swarm optimization algorithms and increase feasibility, an alternative definition method was used instead of the DH method in defining the robot arm kinematic configuration. The effect of the proposed alternative definition method in reducing the computational time is presented through example inverse kinematic analysis. The proposed algorithm was compared with 3 different particle swarm optimization (PSO) variants that include orientation in the inverse kinematic solution of 6 DOF robot arms. Comparative simulation studies were carried out with 20 randomly selected position and orientation data from the workspaces of PUMA 560 and ABB IRB120 manipulators to measure performance of the algorithms. Using the error and computation time values obtained from the simulation results, the algorithms are compared using the Wilcoxon nonparametric statistical test. When the simulation results are analysed by considering the calculation time, positioning accuracy and solution finding rates, it is seen that the Boomerang algorithm is more feasible than the other PSO variants. Verification of the simulation results, and the physical applications were carried out with the ABB IRB120 6 DOF robot arm. Simulation studies and experimental studies showed that the proposed algorithm may be an efficient method for inverse kinematics of time-critical applications. [ABSTRACT FROM AUTHOR]

The study of the ground deformation in active calderas provides valuable indications of the ongoing dynamical processes. In this framework, we analyze the borehole tiltmeter data recorded at Campi Flegrei (Southern Italy) from their first installation (1 April 2015), in order to retrieve the kinematics of the ground deformation and its main anomalies. Our approach involves the nonlinear dynamics analysis aimed at the identification of the degrees of freedom of the system and thus its complexity. Starting from the second part of the year 2020, the behavior of the dynamical system becomes collective, and a locally significant deviation of the deformative pattern from the background trend is observed. In particular, a series of 15 slow tilt variations (like jumps lasting a few days) appears in the ground deformation. They are associated with a very low‐dimensional system likely generated by a local second‐order source. The latter is related to fluid migration and it is superimposed on the primary one located in Pozzuoli town and driving the current uplift of Campi Flegrei. The effects of such a local, second‐order stress field are, indeed, evident in the area of the volcanic dome of Mt. Olibano, where they are measured as tilt steps. The superposition of primary and second‐order sources of deformation acting contemporaneously can justify the recent variations in geophysical and geochemical parameters. Our approach based on the joint dynamical and kinematical analyses of the tiltmeter data can be applied to other volcanic/tectonic areas or extended to other geophysical and geochemical variables. Plain Language Summary: In order to help understand the deformative processes that characterize the bradyseism at Campi Flegrei caldera, we use tiltmeter sensors deployed at various depths in the surveyed area. The tiltmeter network is able to detect slight ground tilt variations of the caldera in both direction and amplitude. In addition to the general uplift of the area recorded since 2005, whose primary source, located in Pozzuoli, generates a radial field, we find some interesting anomalies under kinematics and dynamics profiles. By comparing the ground tilt with seismicity, we notice the greatest release of energy after a large tilt change in July 2018 and, since mid‐September 2020, an increase in the earthquakes' occurrence as well as in the tilt rate. Simultaneously, a second‐order local source overlaps with the primary. In this context, the complex dynamics associated with the volcano becomes more organized and collective. The new approach based on the joint dynamics and kinematics analyses of the tiltmeter data is a powerful tool able to extract features from a complex volcanic region and isolate small signals. Due to its generality, it can be applied to other volcanic/tectonic areas to monitor the background activity or extended to other geophysical and geochemical variables. Key Points: Ground deformation pattern is inferred by tiltmeters analysis at Campi FlegreiNonlinear dynamics analysis identifies the evolution of a complex system that undergoes collective behaviorA deviation from the main source radial deformative pattern in Pozzuoli is observed due to a second‐order local source at Mt Olibano [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to analyze the 6 degrees of freedom (DOF) motion of the spine using the finite helical axis (FHA) in three postmortem human surrogates (PMHS) sled tests. Methods: The sled test configurations corresponded to a 30° nearside oblique impact at 35 km/h. Two different restraint system versions (RSv) were used. RSv1 was used for PMHS A and B while RSv2 was used for PMHS C. The 6 DOF motion of the head and three selected vertebrae have been analyzed using the FHA which describes the 3 D motion of a rigid body between two instants of time as a rotation about and a translation along a unit vector. A minimal amount of rotation is necessary to the FHA calculation, thus the FHA components have been calculated based on a pre-defined interval of 8° of rotation. Results: The analysis of the FHA components demonstrated right lateral bending until around 100 ms, when the rebound phase was reached and the head and the lower spine undergoes left lateral bending. The three PMHS exhibited, in general, flexion movement of the whole body and torsion to the right side of the occupant. This general motion can be associated to the effect of the seatbelt acting as a fulcrum of the rotational movement of the bony landmarks. The interaction of the PMHS with the retention system can be noted by analyzing the time in which the head and the upper spine initiated the rotation and the sudden changes of rotational direction of the three PMHS's head. Conclusions: The rotational analyses have shown to be more sensitive to experimental events than the trajectory analyses for the studied physical tests. Additionally, the results presented in the present study contributes to the analysis of the body kinematics during an oblique impact and adds new experimental data for Human Body Models (HBM) and Anthropometric Test Devices (ATD) benchmarking. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study is dedicated to elaborating and analyzing a technique for autonomous vehicle (AV) motion planning based on sequential trajectory and kinematics optimization. The proposed approach combines the finite element method (FEM) basics and nonlinear optimization with nonlinear constraints. There were five main innovative aspects introduced in the study. First, a 7-degree polynomial was used to improve the continuity of piecewise functions representing the motion curves, providing 4 degrees of freedom (DOF) in a node. This approach allows using the irregular grid for roadway segments, increasing spans where the curvature changes slightly, and reducing steps in the vicinity of the significant inflections of motion boundaries. Therefore, the segment length depends on such factors as static and moving obstacles, average road section curvature, camera sight distance, and road conditions (adhesion). Second, since the method implies splitting the optimization stages, a strategy for bypassing the moving obstacles out of direct time dependency was developed. Thus, the permissible area for maneuvering was determined using criteria of safety distance between vehicles and physical limitation of tire–road adhesion. Third, the nodal inequality constraints were replaced by the nonlinear integral equality constraints. In contrast to the generally distributed approach of restricting the planning parameters in nodes, the technique of integral equality constraints ensures the disposition of motion parameters' curves strictly within the preset boundaries, which is especially important for quite long segments. In this way, the reliability and stability of predicted parameters are improved. Fourth, the seamless continuity of both the sought parameters and their derivatives is ensured in transitional nodes between the planning phases and adjacent global coordinate systems. Finally, the problem of optimization rapidity to match real-time operation requirements was addressed. For this, the quadrature integration approach was implemented to represent and keep all the parameters in numerical form. The study considered cost functions, limitations stipulated by the vehicle kinematics and dynamics, as well as initial and transient conditions between the planning stages. Simulation examples of the predicted trajectories and curves of kinematic parameters are demonstrated. The advantages and limitations of the proposed approach are highlighted. [ABSTRACT FROM AUTHOR]

Inverse kinematics problems (IKP) are ubiquitous in robotics for improved robot control in widespread applications. However, the high non-linearity, complexity, and equation coupling of a general six-axis robotic manipulator pose substantial challenges in solving the IKP precisely and efficiently. To address this issue, we propose a novel approach based on neural network (NN) with numerical error minimization in this paper. Within our framework, the complexity of IKP is first simplified by a strategy called joint space segmentation, with respective training data generated by forward kinematics. Afterwards, a set of multilayer perception networks (MLP) are established to learn from the foregoing data in order to fit the goal function piecewise. To reduce the computational cost of the inference process, a set of classification models is trained to determine the appropriate forgoing MLPs for predictions given a specific input. After the initial solution is sought, being improved with a prediction error minimized, the refined solution is finally achieved. The proposed methodology is validated via simulations on Xarm6—a general 6 degrees of freedom manipulator. Results further verify the feasibility of NN for IKP in general cases, even with a high-precision requirement. The proposed algorithm has showcased enhanced efficiency and accuracy compared to NN-based approaches reported in the literature. [ABSTRACT FROM AUTHOR]

This paper presents an assisted upper limb rehabilitation robot (ULRR) for patients who have experienced stroke who are in the middle and late stages of rehabilitation and have certain muscle strength. The ULRR can complete adduction and abduction motion of the shoulder joint (SJ) in the frontal plane in one step, which can save time and improve the efficiency of rehabilitation training. Based on the principles of ergonomics and rehabilitation medicine, the freedom degree of the upper limb and the motion range of each joint are determined, and the structure of the shoulder, the elbow, and the wrist joint of ULRR are designed. The kinematics model of the robot is established, and the kinematics equations are derived. Meanwhile, the simulation analysis and the workspace analysis of the robot are carried out, and the different movement forms of SJ adduction and abduction are compared and analyzed. Then, the trajectory of the robot is planned to complete the act of drinking water. Finally, an experimental platform is built to complete the ULRR to help participants complete the experiments of drinking water and active training. The experiments verify that the robot is suitable for rehabilitation tasks. [ABSTRACT FROM AUTHOR]