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Robotics is an interdisciplinary field and there exist several well-known approaches to represent the dynamics model of a robot arm. The robot arm is an open kinematic chain of links connected through rotational and translational joints. In the general case, it is very difficult to obtain explicit expressions for the forces and the torques in the equations where the driving torques of the actuators produce desired motion of the gripper. The robot arm control depends significantly on the accuracy of the dynamic model. In the existing literature, the complexity of the dynamic model is reduced by linearization techniques or techniques like machine learning for the identification of unmodelled dynamics. This paper proposes a novel approach for deriving the equations of motion and the actuator torques of a robot arm with an arbitrary number of joints. The proposed approach for obtaining the dynamic model in closed form employs graph theory and the orthogonality principle, a powerful concept that serves as a generalization for the law of conservation of energy. The application of this approach is demonstrated using a 3D-printed planar robot arm with three degrees of freedom. Computer experiments for this robot are executed to validate the dynamic characteristics of the mathematical model of motion obtained by the application of the proposed approach. The results from the experiments are visualized and discussed in detail.

The orthopedic manipulation “bone drilling” is the most executed one in the orthopedic surgery concerning the operative treatment of bone fractures. The drilling process is characterized by a number of input and output parameters. The most important input parameters are the feed rate [mm/s] and the drill speed [rpm]. They play significant role for the final result (the output parameters): thermal and mechanical damages of the bone tissue as well as hole quality. During the manual drilling these parameters are controlled by the surgeon on the base of his practical skills. But the optimal results of the manipulations can be assured only when the input parameters are under control during an automatic execution of the drilling process. This work presents the functional characteristics of the handheld robotized system ODRO (Orthopedic Drilling Robot) for automatic bone drilling. Some experimental results are also shown. A comparison is made between the similar systems which are known in the literature, some of which are available on the market. The application areas of ODRO in the orthopedic surgery practice are underlined.

The advanced tendency in development of robots oriented to orthopedic manipulations is maximally simplification of their mechanics. So called Handheld Robotized Systems appear. Here handheld bone drilling robotized system ODRO (Orthopedic Drilling Robot) is considered. The purpose is to compare its functional characteristics with the similar systems known in the literature. Experimental results are presented for porcine femur drilling by new drill module. The stop drilling decision is taken automatically. The information about experiments concerning the different modes is shown on the display after the drilling end. Handheld robotized systems can perform the accuracy and precise work like the stationary multifunctional robots. They do not need special software, pre-operative planning procedures, calibration, registration and systems for intraoperative navigation. In the same time they are much cheaper, accessible for usage, convenient for work and maintenance which will facilitate their mass application in the orthopedic surgery practice.

Development of hand-held surgical robot for automatic bone drilling George Boiadjiev 1,2 , Kamen Delchev 2 ,Tony Boiadjiev 3 , Rumen Kastelov 4 , Kazimir Zagurski 5 1) Faculty of Mathematics and Informatics, Sofia University, Sofia, Bulgaria 2) Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria 3) Institute of Information and Communication Technologies, Bulgarian Academy of Sciences, Sofia, Bulgaria 4) Orthopaedic and Trauma Clinical Centre of Ministry of Domestic Affairs, Sofia, Bulgaria 5) Institute of system engineering and robotics, Bulgarian Academy of Sciences, Sofia, Bulgaria This paper represents the development of a prototype robotic system for automatic bone drilling in orthopedic surgery. Answering the surgical requirements for the robot dimensions and weight to be as small as possible a new design of the mechanical structure is proposed. The new structure design is based on idea of parallelism of the axis of the linear actuator and the axis of the rotary one. The control system is improved by using of a new micro-controller. A new type of linear drive and a new force sensor (load cell) are built in so that the quality characteristics of the “Orthopedic bone Drilling Robot” (ODRO) are not only the same as previous its versions [1, 2] but become better. An experimental setup is arranged and experiments are executed to test and verify the robot quality features and functional capabilities. References 1. G. Boiadjiev, T. Boiadjiev, V. Vitkov, K. Delchev, R. Kastelov, K. Zagurski, Robotizeed System for Automation of the Drilling in the Orthopedic Surgery. Control Algorithms and Experimental Results., Proceedings of the 9th IFAC International Symposium on Robot Control (SYROCO 2009), Gifu Japan, September 9-12, 2009, pp 633-637, (2009). 2. Boiadjiev, G., Kastelov, R., Boiadjiev, T., Kotev, V., Delchev, K., Zagurski, K., Vitkov, V., Design and performance study of an orthopaedic surgery robotized module for automatic bone drilling, International Journal of Medical Robotics and Computer Assisted Surgery, 9(4), pp. 455–463, (2013).

This work presents the development of a redundant planar robot created with a 3D printer. The mechanical structure and the main kinematic dependencies are discussed. The hardware and software implementation of the prototype are presented. An algorithm is presented to find solutions of the inverse kinematics problem in the presence of obstacles in the workspace of the robot. The algorithm gives results on possible solutions both in the Cartesian coordinates and joint angles. The proposed software and the obtained results are the basis for planning trajectories of the robot in complex environments with obstacles. The created prototype is used for education of students in robotics and mechatronics. The advantages of using 3D printing technology in modeling and design and its application in the education process are highlighted.

Far cortex detection during the bone-drilling process is a specific task in orthopaedic surgery. Any errors in its execution could damage the cortex wall from the inside, which often causes additional trauma even with a fatal result. Here we present some functionality enhancements of the drilling orthopaedic robot ODRO concerning the solution of the far cortex detection problem. The solution is based on software control of the thrust force applied to the bone during the drilling process. A new algorithm is created and its software realisation is provided. Experimental results are presented which verify and confirm the new functional characteristics of the robot. The risk of far cortex damage may be avoided by robot application and such precise operations may guarantee better success.

The need of the most precise manipulations in the orthopedic surgery concerns spine. The drilling takes place very often there. If spine cortices are broken by mistake then fatal problems appear as paralysis, block of breathing and death. Therefore in operation as pedicle drilling the far cortex perforation must be avoided. This paper shows that it can be done by bone drilling hand-hold robot ODRO. It is able to detect the bone far cortex and stops just before contact registration. Experimental results are presented. Also the results based on new algorithms and software are presented and discussed.

This paper discusses a problem appeared by drill bit bending during bone drilling in the orthopedic surgery, where precision is needed for screws to be implanted. The bone surface has a specific shape and the drill bit may slip a little along the bone before the process start, when a large thrust force is applied by hand-drilling. That could be seen and correct by the surgeon. But he can’t see inside – where the second cortex drilling starts. The drill bit bending leads to the worse screw fixation and even to the bone damage – if the drill bit stays off broken inside. To solve this problem an active force control is made by robot application. Experiments and results are presented.

This paper deals with an active force control for automatic bone drilling. Orthopedic surgery often requires precise bone drilling for screws to be implanted. The hole quality in drilling process strongly depends on the applied thrust force (resistance force). In particular, a relatively large thrust force, applied in hand-drilling process, could cause a bone trauma (thermo necrosis or bone damage). To solve this problem we apply an active force control in order to achieve constant and safety drilling thrust force. Moreover, we propose an algorithm for parameter tuning of the considered control system.

Bone drilling and cutting manipulations are widespread in the orthopedic surgery. In free hand performance of them some errors such as an inaccurate penetration and dilate of bone hole, overheating, harm soft tissues could be occurring. The goal of this study is to design and develop control concept for a bone drilling and cutting robotized system. The proposed orthopedic system consists of two executive modules for drilling and cutting and common control panel. The control algorithms and programs for drilling have done and given in the paper. We are developing the control algorithms for cutting manipulation.

Bone drilling manipulationstake placevery ofteninthe orthopedic surgery. The successful execution of bone drilling requires a high level of dexterity and experience. The patient’s recovering depends on the operation performance. This paper presents a design concept of a bone drilling hand-hold mechatronic system. It is based on the modified structure of the previous our robot ODRO. It isable to detect the bone breakthrough and the stops. It is intended to perform drilling a preliminary set depth. Resistantforce is measured and experimental results are shown.

In orthopedic surgery the manipulation “bone drilling” is used very often and it is performed by hand drilling, which causes a lot of problems—getting the big outlets, breaking the tendons or blood vessels, protecting the rear bone wall (which brings one more cutting of the tissue), overheating, and so on. Automatic bone drilling could successfully solve these problems. The drilling orthopedic robot (DORO) is presented as a device for automatic bone drilling execution as well as its technical features and functional applications. The experimental results are shown for identification of the parameters of the drilling process, including the bone structure in part.

We proposed a new approach for redundant robots trajectories planning, based on the Null space (or Kernel) features. The Null space (Kernel) exists only in the case of redundant robots and it describes these joints motion which do not affect the robot end-effector motion in the sense of both position and orientation. Based on this “hidden motion” realized in the configuration space, which does not affect the motion in the working zone, we can control independently the robot end-effector position and orientation motions, or just maintain its state while some external force is applied to it. The proposed control strategy is simple, no additional penalty functions are used to restraint the end-effector motion as in the case of the conventional methods. No pseudo inverse kinematics calculations are required; the desired trajectories are generated directly in the configuration space. No complicated control schemes are introduced, the proposed method is based on solving algebraic systems of equations and finding eigenvectors and eigenvalues. In the paper the results from simulations and experiments based on the proposed method are presented and discussed.

The aim of this paper is to present an autonomous control system for active ankle-foot orthoses (AFO). An ankle-foot orthosis is commonly used to help persons with weakness of ankle dorsiflexor muscles due to peripheral or central nervous system disorders. The proposed orthosis has one degree of freedom which foot segment is connected to the shank segment by a rotational joint. In order to assure automatic adaptation of the joint torque the joint is fitted with direct drive actuator attached laterally and controlled by a microcontroller ATmega128. Realizing flexion/extension the actuator applies a torque adequate to the joint position of the human ankle during level ground walking. The control signals are received from two tactile sensor arrays incorporated in the foot part of AFO and in the insole of the healthy leg. During each gait cycle a microcontroller estimates the forward speed and modulates the swing phase flexion and extension in order to achieve quite normal walking dynamics. A feedback with Proportional-Integral-Derivative control (PID control) was used to estimate the trajectory of the foot and positioning the actuated foot segment of the AFO when the foot rotates about the ankle. A graphical presentation of the mathematical model and simulation of the dynamic system is done building a Matlab Simulink block diagram model. The proposed intelligent system is oriented to control different models of personalized ankle-foot orthoses designed using reverse engineering and rapid prototyping by the joint team Bulgarian Academy of Sciences/Cardiff University.

Bone drilling and cutting procedures are widely used in orthopedic surgery. Relatively high forces and temperatures experienced during bone drilling and cutting can cause significant damage to the bone as necrosis, widening of holes, breaking the tendons or blood vessels, which can make patient recovery long and painful. This paper presents a concept design of a hand-held robotized orthopedic system for bone drilling and cutting manipulations. The system consists of two executive modules for drilling and cutting, respectively. : bone drilling module detecting bone breakthrough is developed. It can monitor time, linear velocity, angular velocity, resistant force, depth of penetration and temperature during the drilling process. A design concept of a robotized oscillating saw for bone cutting is also presented. The saw is intended to perform cutting operations with preliminary setting of depth and stop automatically after the cutting process is completed. Cutting conditions will automatically change in accordance with bone density. Dynamical model using graph theory and the orthogonality principle is provided. CAD models of the prototype of the robotized bone cutting module are presented.

We propose a novel solution to the problem of path planning for redundant robot manipulators. The desired joint trajectories, generated according to the proposed approach allow the robot to change independently its end-effector position and orientation motions. The algorithm has successfully been used to make one 7 degrees of freedom robot with class-5 revolute joints track a desired image trajectory.

This paper introduces a control method for obstacle avoidance of a mobile robot. First, the mobile robot detects obstacles by information of both a CCD camera and ultrasonic sensors. Then, using information of both of camera and sensors, the mobile robot generates a dynamic trajectory to go to the goal point avoiding the obstacles. Through some experiments, a usefulness of proposed method is shown.

This work presents a modified computed torque method application for a 7 d.o.f. robot control. Generally it could be applied to any other robotics system. The effectiveness and stability of the proposed controller have been discussed and the results from experiments presented. The proposed control method introduces additional corrections for the joints positions, velocities and accelerations and can compensate uncertainties due to the inexactness of the dynamics, describing the system or some parameter variation.

This work is dedicated to position control of redundant robots, realized with the help of the sensibility theory. The control method allows controlling the robot position following some working trajectory, and at the same time maintaining its orientation state unchanged or vice-versa. The latter is achieved by using the features of the four robot configuration space orthogonal fibrations. Their characteristics and role are clarified. A concept of robot image trajectories is formulated and its application is analyzed. The proposed method is going to be applied for a real-time control to a 7 d.o.f. robot, based on Puma type construction. Simulations have been done for it, taking into account its dynamics and sensibility models and also by applying the position control method. The results and conclusions are presented.

This work is dedicated to force control of redundant robot-manipulators using the sensibility approach. It allows the robot to react to external force appearance without changing its kinematics state. The sensibility factor-group is introduced for description and analysis of the robot configuration space orthogonal fibrations. They divide the robot configuration space into four sets, each responsible for separate motion realization - one for position, one for orientation, one for both and one which does not affect the kinematics state. A concept of robot kernel trajectories is formulated and its application is clarified. The proposed approach is aimed to be applied for real time control of 7 d.o.f. robot. Simulations have been done for that robot taking into account its dynamics and sensibility models and applying the force control method. The results are presented further.