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This paper proposes a method of hip and knee joints coordination control planning based on virtual force. Firstly, the kinematic model of biped robot is established according to the physiological structure of human body. Secondly, the kinematics equation is established based on the jumping motion characteristics of the hip and knee joints, and the motion angles and angular velocities of the hip and knee joints are solved by inverse kinematics. Then, in order to optimize the motion posture, balance the driving power of the joints, and reduce the driving burden of the knee joint, a coordinated hip-knee joint control strategy and its implementation method for biped robot jumping motion are proposed based on virtual force control method. Finally, the effectiveness of the proposed method is verified by comparing and analyzing the simulation data of biped robot with the measurement data of human motion.

Unmanned road roller has become an attractive solution to reduce operators’ working intensity and improve compaction efficiency. As a result of working in bumpy environments, sideslip effect is unavoidable during the compacting process. In order to guarantee the reliability and stability of path tracking control, a novel and effective method based on preview control and sideslip compensation is proposed in this paper. The kinematic and dynamic models of articulated road roller considering sideslip angles are obtained first. Then, a preview controller with sideslip compensation (PCSC) is developed to eliminate the path tracking errors between the actual path and the desired path. To evaluate the control performance of the proposed method, simulation under the MATLAB/Simulink and automatic compaction experiments at the construction site were performed with initial errors. Finally, the simulation and experimental results show that the path tracking errors can converge to zero as time goes by. The proposed method has the ability to navigate an articulated road roller to track a desired path in the existence of sideslip, only regarding the steering angle dynamic as control input. Compared with other benchmark method, it not only improves the control accuracy, but also increases the convergence rate, proving its effectiveness and feasibility. All these also demonstrate the practical value and validity of the proposed models with sideslip.

For the purpose of reducing unrecoverable economic losses and casualties all over the world, automatic fire detection is expected to recognize fire and give an alarm as early as possible. Due to the disadvantages of traditional methods, fire image detection has become an attractive solution. This paper pro-poses an innovative approach, based on multi-feature vector and support vector machine coupling with improved particle swarm optimization (IPSO-SVM). Firstly, a multi-feature vector is established, including geometric, texture, spectrum information. Then, an improved particle swarm optimization (IPSO) is developed by introducing dynamic inertia weight factor and cross-variation. Next, an IPSO-SVM model is established to achieve the fire image detection, where the IPSO algorithm is imported to select the optimal parameters of support vector machine (SVM). Afterwards, the detection performance of presented method is verified by a series of case studies. Eventually, the results indicate that the provided method has an advantage over other benchmark algorithms, obtaining the highest rate of 98.33, and proving its effectiveness and feasibility.

Multiload AGVs, which can carry more than one container at a time, are widely used in automated container terminals. The dispatching decisions for multiload AGVs serving in automated container terminals on the target of minimum travel distance are significant in the process of container transportation in terms of improving operating efficiency. Previous work usually focused on AGVs working in a single-carrier mode, which was not only inconsistent with actual circumstances but also a waste of resources. In this paper, we establish a new mathematical model to describe multiload AGVs operating in automated container terminals, which is closer to the actual situation in real terminals. Based on this improved model, we propose a priority rule-based algorithm, termed as shuffled frog leaping algorithm with a mutant process (SFLAMUT), which can increase the diversity of the population and improve the convergence rate. Experiments were carried out based on data generated randomly according to the working properties of container terminals, and it is observed that the proposed SFLAMUT presents an effective and efficient exploration process and yields promising results in solving the proposed mathematical model.

Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work efficiency. In order to achieve the path following control, considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a state-feedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What’s more, to evaluate the performance of the proposed method, simulation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial displacement error (−1.5 m), heading error (−0.11 rad) and steering angle (−0.19 rad). Finally, simulation and experimental results show that the errors and steering angle can decrease gradually, and converge to zero with time. Meanwhile, the control input is not saturated. An articulated drum roller can lock into a desired path with the proposed method in uneven fields.

In modern robot navigation systems, path planning plays an important role to search the most efficient path throughout the selected environment. In this paper, a novel and effective method is proposed to achieve path planning, combined with extended MAKLINK graph and improved ant colony optimization (IACO). Firstly, the MAKLINK graph is extended to consider not only convex polygonal obstacles but also concave polygonal obstacles. To overcome the disadvantages of traditional ant colony optimization (ACO), an improved ACO is developed by introducing an adaptive updating rule of pheromone. Finally, the simulation results demonstrate that the proposed method is superior to methods based on Dijkstra's algorithm and traditional ACO, planning the shortest path in the complex space environment of concave-convex polygonal obstacles. Compared with traditional ACO, the IACO not only improves the convergence rate and global search capability but also skips the local optimal, proving its effectiveness and feasibility.

Module layout of emergency rescue equipment box is a special three-dimensional (3D) bin-packing problem, whose mathematical description is that under the condition of fixed capacity, the corresponding value of equipment in the box is maximized. Through the analysis of the characteristics of the emergency rescue equipment box, three evaluation indexes, including the average height of centroid, the average distance of access and the functional distance of equipment, were proposed first. In order to obtain a more ideal 3D packing scheme, a module layout method based on layer space using genetic algorithm was also proposed. These equipments to be arranged were encoded in decimal. According to the fitness function and the objective function, the selection, crossover and mutation operations of decimal sequence were conducted. After the iteration, the value of objective function gradually approached to the optimal solution. To evaluate the performance of the proposed method, some simulations under the MATLAB were performed. Finally, the experimental results show that the proposed method can achieve a better optimization effect, proving its effectiveness and feasibility.

Transition-metal light-element compounds are currently raising great expectations for hard and superhard materials. Using the widely attracting osmium (Os) and its borides (OsB, Os2B3 and OsB2) as prototypes, we demonstrate by first-principles calculations that heavy transition metals, which possess high stiffness but low hardness, can be converted into highly hard materials by incorporating of light elements to form compounds. Such a crossover is a manifestation that the underlying sources of high stiffness and high hardness are fundamentally different. The stiffness is related to elastic deformation that is closely associated with valence electron density, whereas the hardness depends strongly on plastic deformation that is determined by bonding nature. Therefore, the incorporation of light atoms into transition metal should be a valid pathway of designing hard and superhard materials. This strategy is in principle also applicable to other transition-metal borides, carbides, and nitrides.

In order to improve the efficiency of an underwater beam installation process, a computer-controlled position adjustment system is established. High accurate underwater position measurement is required in the system to ensure the fitting accuracy of two beams in the fine adjustment. This paper presents a visual measurement method using two pairs of underwater bi-camera vision system. Because the beams are of large size, appropriate markers as the measuring objects are coated on the rails fixed on two beams. A tank filled with clear water is put in front of each underwater camera to reduce the backscattering effect caused by turbid water. In order to solve the inaccuracy of position measurement due to blur edges and unclear contours on the images from the underwater cameras, super resolution as well as other image processing methods has been applied. By analyzing the extracted features from some interest lines and points of the processed images of markers, the position of the beam can be obtained. Results have shown that the position measurement errors are acceptable and the method can be used practically.

Accurate combustion state recognition of flame images not only plays an important role in social security, but also contributes to increasing thermal efficiency and product quality. To improve the accuracy of feature extraction and achieve the combustion state recognition, a novel method based on radial Chebyshev moment invariants (RCMIs) and an improved firefly algorithm-wavelet support vector machine (IFA-WSVM) model is proposed. Firstly, the potential flame pixels and the potential flame contour are obtained in the pre-processing phase. Then, the rotation, translation and scaling (RTS) invariants of radial Chebyshev moments are derived. Combing the region and contour moments, the RCMIs of pre-processed and edge images are calculated to construct multi-feature vectors. To enhance the recognition performance, an IFA-WSVM model is built, where the IFA is applied to search the best parameters of WSVM. Then, the IFA-WSVM model is used to recognize the combustion state. Finally, the result for case studies show that the proposed method is superior to methods based on HMIs and ZMIs, achieving the highest rate of 99.07% in real time. The IFA algorithm also outperforms other benchmark algorithms. Even for the images transformed by RTS and small size of training sets, the proposed method continues to exhibit the best performance.

The flow channel structures of turbo-charged pipes used in vehicle engines should exhibit superior noise reduction and less pressure loss. A design model of nylon blow molding structure as a turbo-charged pipe is introduced in this paper. The integrated analysis of noise reduction and pressure drop over a flow channel inside a blow-molded pipe is carried out by the method of multiphysical field collaborative simulation. The coupling relation between noise reduction and pressure drop to access a combined optimization is innovatively established by defining the actual physical modes. Based on the design parameters, the blow molding for the design model is implemented in detail and, some valuable conclusions are drawn suggestive to the actual technology process. The experimental verification for the pipe sample indicates that the developed channel structure can meet the requirements of both noise reduction and pressure drop. This proposed design method can be referred for the development of blow-molded pipes.

With the aggravation of the energy crisis, people pay more and more attention to the rational utilization of energy. Thus the construction machinery field has started to take hybrid technology into consideration to save the energy. This paper analyses the working condition of a 5 tons loader and develops the hydraulic parallel hybrid scheme which has little research in the loader field. The system adopts a dynamic rule-based control strategy, which takes the required torque and the SOC value of the accumulator as the input to realize the output torque of the engine and the pump/motor. A power-train model is also developed in the paper. The results show the scheme can reduce the fuel consumption by 13.5% compared to the conventional loaders.

The different radial support ways for a rotation prism are presented to evaluate the strains and stresses induced by the gravity action and the thermal effects. Due to the large-aperture, non-uniform quality distribution and especially rotation from 0° to 360°, neither the multi-point support way nor the full surface-contact support can well meet the assembly requirements. The paper proposes a novel project of an adjustable partial surface-contact support way to solve this support problem. The maximum strain and stress under this support way both are less than the tolerance limit of the strength assurance regardless of the prism rotating to any position. Meanwhile, the thermally-induced structural analysis is performed to predict some specific work cases, which is much valuable for the improvement of the assembly design.

Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject. In order to improve the energy efficiency and driving range of a motor hoist, a regenerative braking system is designed and discussed. The system takes a unique ultracapacitor-only approach to energy storage system. The bi-directional bride DC/DC converter which regulates current flow to and from the ultracapacitor operates in two modes: boost and buck, depending on the direction of the flow. In order to provide constant input and output current at the ultracapacitor, this system uses a double proportional-integral (PI) control strategy in regulating the duty cycle of PWM to the DC/DC converter. The permanent magnet synchronous motor (PWSM) drive system is also studied. The space vector pulse width modulation (SVPWM) technique, along with a two-closed-loop vector control model, is adopted after detailed analysis of PMSM characteristics. The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment. A test platform is built to obtain experimental results. Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system. Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.

In order to solve the nonlinear contact problem with the friction action in the mirror assembly, the modeling analysis is carried out by the MPC method of shell-to-solid coupling. Considering the friction factor existing in the contact region, the deformation and stress of the strap obviously changes from fixed region, transition region to contact region, which further produces a serious edge effect around the mirror and leads to the uneven stress distribution. The results show the maximal deformation of the assembly is 9.98 μm and the maximal stress is 10.5 MPa, which has much tolerance to the precision requirement of structure and the admissible stress of material; the influence of heat effect on the surface deformations of mirror is proved to be far greater than that of only gravity load. The advantages of the contact model built by the MPC method are more close to the actual working conditions and more accurate analysis results can be obtained.

Large-scale synchronous hoisting equipment is widely used in the construction field. A coupling analysis method for global and local structures exposed to synchronous hoisting loads under working conditions is presented. An integrated analysis flow based on virtual prototyping is provided for the coupling analysis process with different design and simulation software tools, which includes project design, CAD and CAE model-building and interchange, data coupling and analysis. The theoretical basis of finite element analysis for synchronous hoisting loads is deduced. A practical case of the coupling analysis for a large-scale structure exposed to synchronous hoisting loads is studied and validated. The coupling analysis method can well improve the analysis level and efficiency to predict the mechanical effects in an operating situation.

An analytical reverse solution and actual examples are given to show how to direct a laser beam from a pair of orthogonal prisms to given targets in free space. Considering the influences of double-prism structural parameters, a lookup table method to seek the numerical reverse solution of each prism's tilting angle is also proposed for steering the double-prism orientation to track a target position located in the near field. Some case studies, as well as a specified elliptical target trajectory scanned by the cam-based driving double prisms, exhibit the significant application values of the theoretical derivation. The analytic reverse and numerical solutions can be generalized to investigate the synthesis of scanning patterns and the controlling strategy of double-prism tilting motion, the potentials of which can be explored to perform the orientation and position tracking functions in applications of precision engineering fields.

Based on practical experience and pertinent theory analyses, error between real location of liquid-solid interface (Z) value and optimal Z value (EZ) and its deviation of derivatives (dEZ) were selected as inputs, and cooling distance (L), pulling speed (V) was selected as output. The closed-loop control process in OCC processing was simulated through designed fuzzy control algorithm. The simulation results showed that object variable Z value could return to optimal value in 50 seconds through designed fuzzy control device. And the control process had good stability. Even when random disturbance happened in control process, object variable also could return to stability quickly. Designed fuzzy control device could satisfy OCC process requirement.

The research purpose of this paper is to build a platform for image processing, which can be used to minimize and intelligentize the video image processing system, and make it applicable in various and complicated situations. During the design, related data in broad area has been searched, video processing systems of various engineering vehicles are used as reference, the merits and demerits of different methods are analyzed, then the FPGA-based program is chosen. FPGA-based image acquisition PCB is designed in this paper, the working mode is configured and the acquisition controlling module is programmed. Under the control of the controlling module, image data is stored in SRAM correctly. An arm module is also designed according to ARM theory and timing relation, which is used for the reading of image data and fitness algorithm of the road mark line. Finally the complete program of the video tracking system used for the 900T transporting girder vehicle is programmed. The above research validated that this system is totally qualified for large-scale engineering vehicles' video surveillance and safety precaution, which can be used in various engineering vehicles' controlling system, and has a broad prospect.

This paper focuses on the study and experiment of vision control system for an inverted pendulum. To solve some key technical problems, the hardware platform and the software flow of the control system have been designed. The whole control system is composed of vision module and motion control module. The vision module is based on "CCD camera", the motion control module is based on "Motion Control Card, Servo Driver and Servo Motor", and the software is based on LabView. The main research contents and contributions of this paper are summarized as follows: (1) Analyze the functional requirements of the vision control system about the inverted pendulum, developing the hardware platform and planning the overall arrangement of the system; (2) Design the image processing flow and the recognition track process of the moving objects. The accurate position of the pendulum can be obtained from the image through the flow, which concludes image pretreatment, image segmentation and image post-processing; (3) Design the software structure of the control system and write the program code. It is convenient to update and maintain the control software due to the modularity of the system. Some key technical problems in the software have been solved, so the flexibility and reliability of the control system are improved; (4) Build the experimental platform and set the key parameters of the vision control system through experiments. It is proved that the chosen scheme of this paper is feasible. The experiment provides the basis for the development and application of the whole control system.

An improved ZLM15B distributed power-driven wheel loader was designed, whose travel and brake system was accomplished by two permanent magnet synchronous motorized-wheels instead of traditional mechanical components, and whose hydraulic systems such as the working device system and steering system were both actuated by an induction motor. All above systems were flexibly coupled with 3-phase 380VAC electric power with which the diesel engine power is replaced. On the level cement road, traveling, braking, traction and steering tests were carried out separately under non-load and heavy-load conditions. Data show that machine speed is 5 km/h around and travel efficiency of motorized-wheels is above 95%; that machine braking deceleration is between 0.5 and 0.64 m/s 2 but efficiency of motorized-wheels is less than 10%; that maximum machine traction is above 2t while efficiency of motorized-wheels is more than 90% and that adaptive differential steering can be smoothly achieved by motorized-wheels.

The laser tracking measurement for space moving targets is the research hotspot in the precision measurement field, which has attracted many researchers' interests for many years. The tracking mechanism characterized with the performance of high accuracy and rapid response is the key to solving the dynamic measurement problem. In the paper, a project with one prism rotating around the rotating axis to attain the linear tracking is proposed, which can not only meet the requirements of the large range, rapid response and dynamic tracking, but also achieve the high accuracy of submicroradian magnitude due to the particular opto-mechanical design. Steering the tracking mechanism can well track the linear motion of space dynamic or static target. In order to study the above system, the technical parameters of the mechanism are firstly designed, and then the model analysis and simulation calculation is respectively carried out. Therefore, a new measurement is finally brought about, which points outs a solution for the measurement of space moving target with large range and high accuracy. The design results show the tracking accuracy is better than 0.5 μrad within the tracking angle range.