With the continuous development of mechanical equipment towards high-speed, large-scale and intelligent, fault prognostics and health management(PHM) has been a hot issue in industrial field.The working environment of mechanical equipment is poor, the working conditions are complex, and multiple systems are coupled with each other, so the condition monitoring information presents the typical big data 4 V characteristics of “huge volume, multi-source heterogeneous, fast generation and sparse value” during long-term service.This makes the health management of mechanical equipment in the context of “big data” presents “three highs” features:(1) high-capacity big data storage capability is required;(2) high-efficiency real-time processing capability is required;(3) high-strength heterogeneous adaptation is required.There is a need for a data processing method that can adaptively extract fault features from massive data and perform diagnostic and RUL prediction.As a further development of machine learning, deep learning theory has achieved great success in fields of image processing, speech recognition, and natural language processing with powerful modeling and data processing capabilities.Applying deep learning theory to solve the problem of equipment fault prognostics and health management(PHM) in the era of “big data” has become a hot research point.Starting with the basic process of deep learning in equipment fault prognostics and health management applications, the main types and characteristics of neural network input features applied in PHM were summarized.The four types of neural network models and corresponding model training algorithms in PHM applications were summarized, and the research progress of deep learning in PHM applications at home and abroad was reviewed.The future development directions of deep learning in PHM application were pointed out.

A multi-robot system can reliably perform high-efficiency operations that cannot be completed by a single robot.It becomes a research hotspot for building intelligent production lines.The research status of multi-robot system was summarized from the aspects of multi-robot mechanism optimization layout method and multi-machine task allocation technology, and the development trend of the technology was analyzed and expected, aiming to show the future research direction in this field.

With the widespread use of robots in mechanical processing,handling and palletizing,welding and painting,health care and other operations,collision detection becomes a key part of the safety of the man-machine and machine-machine.Collision detection algorithms were classified according to different directions,the characteristics and applications of diverse algorithms in various fields were discussed.The status of collision detection in the field of special robots,multi-legged robots,industrial robots and service robots were described.By analyzing the detected object and working environment,combining the characteristics of different collision detection algorithms,the best collision detection algorithm was obtained when robots worked in different environments and fields.Finally,the shortcomings of the current collision detection algorithm in the field of robotics and the thinking and suggestions for future development were summarized.

Based on the calibration technology of the distance error model, the model relationship between the distance error of the robot end and the kinematics parameter error of the robot was established, the transformation error of the coordinate system in the calibration process was avoided, and the calibration accuracy could be improved significantly. The vision measurement technology has the advantages of high precision, non-contact and real-time, compared with traditional methods, it has the advantages of low cost, easy operation. A robot calibration method which combined distance error model with vision measurement technology was proposed to improve the accuracy of industrial robots in specific workspace. A binocular vision system was adopted, and the camera was placed outside the robot for measurement. The robot parameters were calibrated based on the distance error model, and the kinematics parameters were compensated by using the calibration results. The results show that the distance errors are improved in a given calibration workspace; on the calibration trajectory, the average error of the absolute distance is reduced from 0.279 9 mm to 0.104 4 mm, and the error of the uncalibrated trajectory is decreased by more than 50%, by which the correctness and feasibility of the method are proved.

Aiming at the problems of low efficiency and slow convergence caused by sparse reward in path planning of mobile robots with deep reinforcement learning,a gradient reward policy was proposed. Region segmentation was used to divide the environment into buffer zone,exploration zone,adjacent zone and target zone,the dynamic change of reward could gradually reduce the exploration scope of the robot,and at the same time,it could also obtain positive rewards in safe area. The robot current position coordinates were input,the Q values of the four actions were estimated after passing through the neural network,then the exploration was maximized through the decapitation dynamic greedy strategy,finally the priority experience playback based on the mean square error was used to extract samples to update the network with gradient descent. The experimental results show that the exploration efficiency can be improved by nearly 40% in a small-scale environment,and the success rate is higher than 80% in a large-scale environment,the robustness is enhanced while improving the exploration efficiency.

Electro-mechanical braking is an important type of brake-by-wire.A rear electrical-mechanical brake(EMB) caliper was designed for a sample vehicle in an enterprise.Based on the stiffness curve of caliper, the simulation model of the clamping force control was established, and the response characteristics of the clamping force were verified by experiments.The EMB caliper clamping force output can follow the step, sine and random target curves with good dynamic response characteristics, which meet the design requirements.The simulation model can be used to accurately simulate the change of the caliper clamping force and piston displacement.At the same time, caliper stiffness has a significant impact on the accurate control of EMB caliper clamping force, and the accurate control of EMB caliper clamping force should be based on the accurate estimation of caliper stiffness.

The each leg of bionic hexapod robot has three rotating joints. The torso is a 3-U^rRS parallel mechanism in tripod gait. The constraint of three chains on the movement of upper platform was analyzed through the screws theory and the orthogonal product. The Degree of Freedom (DOF) of mechanism was analyzed. Actuate joints were fixed in different actuator dispositions, the constraint lines on platform acted by each branch chain were analyzed, and the Jacobian matrix of parallel mechanism was established. The Jacobian matrix simulation and verification were carried on by ADAMS. Jacobian matrix analysis of the mechanism is of important significance to analysis of achievable space, synthesis of the mechanism dimension, path planning and coordinate control.

A type approval test platform for hydraulic motor was designed, which mainly involved hardware system, measurement and control system and test software.The maximum test pressure of the platform was 40 MPa, the maximum test flow rate was 1 000 L/min, the maximum test rotation speed was 3 000 r/min and the maximum test torque was 45 000 N·m.The test accuracy level of the system was class A,which could basically meet the type test requirements for hydraulic motors with different specifications and models.The platform was used to test the volumetric efficiency, total efficiency, the lowest speed and starting efficiency of low speed high torque hydraulic motor and cycloid hydraulic motor with 10 different specifications.The results show that the total efficiency and the lowest speed of several hydraulic motors are not in compliance with the requirements of industry standards, the quality of these products needs to be improved.The platform has been used for the third-party inspection of hydraulic motor products.

In order to realize the bidirectional driving of data between industrial robot and digital twin,a virtual-real linkage system for industrial robots was developed based on the digital twin system architecture. A virtual scene of the system was built in Unity3D,and various methods such as joint control,end point control,and end trajectory control were established to realize the simulated motion of the virtual robot. Based on the Socket network communication mode of the TCP/IP protocol,the two-way transmission of the robot pose state and other data was used to drive the synchronous motion of the virtual and real models. After testing,the system has good real-time performance and immersion,which can meet the real-time monitoring and visual control requirements for industrial robots.

Prediction of remaining useful life (RUL)of rolling bearings is of great significance to ensure smooth operation of rotating machinery.Aiming at the problems of large fluctuation of prediction accuracy and low data utilization rate of time domain features,a rolling bearing RUL prediction method was proposed based on the fusion feature of time domain and spectral kurtosis and exponential degradation model.The features of signals extracted from time domain and spectrum kurtosis were smoothed and sorted based on monotone scale,and then the dominant features were selected to construct health indicators through principal component analysis (PCA).Then,the degradation point was determined by the 3σ criterion and the data were reprocessed.Finally,the RUL of bearing was predicted at every moment based on Bayesian theory and maximum likelihood function estimation of exponential degradation model parameters.The XJTU-SY dataset were used to verify the effectiveness of the proposed method.The results show that the proposed method can mine potential information of small sample data based on current observation bearings and accurately characterize the degradation process of non-stationary signals under strong noise background,thus improving the prediction accuracy of RUL.

In order to reduce commissioning cycle and cost and predict system-level risk in advance,a design method of fixed rail logistics picking virtual commissioning system based on digital twin was proposed,which was based on the consistency of virtual and real characteristics of digital twin.According to the characteristics and commissioning requirements of fixed rail logistics picking system,the virtual physical model,virtual execution system and virtual control system were established.Then the controller-virtual model interface was designed to realize the communication between virtual and real.The effectiveness and practicability of the virtual debugging based on the digital twin model were verified by an example of logistics picking system.The virtual debugging system of fixed rail logistics picking based on digital twin can reduce the debugging cycle and cost of logistics picking system,and then improve the debugging efficiency.

Compared with single robot, multi-robot system has the characteristics of higher working efficiency and better flexibility, which has received increasing attention. Trajectory planning determines the operating efficiency and motion performance of its end effector. The multi-robot system has a large amount of calculation for the coordinated trajectory planning of each robot in the case of large-scale overlapping of workspaces. Various methods of multi-robot trajectory planning were analyzed and summarized in detail from the aspects of basic trajectory planning, optimal trajectory planning and deep learning, and the technology development trend in this field was analyzed and prospected which indicated the research direction of future work.

Aiming at the disadvantages of the traditional after-valve compensation load sensitive hydraulic system with lower pressure side pressure compensation valve, such as high temperature rise, low service performance and low service life, an improved after-valve compensation load sensitive hydraulic system with two liquid resistance shunt in parallel was proposed. AMESim simulation software was used to build the system model and the simulation analysis was carried out.The results show that under the same working conditions, the improved load sensitive system can flexibly reduce the energy loss of a single pressure compensation valve, and improve the performance and service life of the system and components.The conclusion provides reference for the optimal design of the after-valve compensation load sensitive hydraulic system.

In order to understand the UR5 robot real-time trajectory changes, according to the Denavit-Hartenberg parameter method, by using the Link function in MATLAB Robotics Toolbox, a three-dimensional mathematical model of UR robot was built. The positive and inverse kinematics of UR5 robot was analyzed. The relation between the angles of each joint was deduced. Three-polynomial interpolation method was used to analyze the theoretical space trajectory planning between the points. Combined with the MATLAB Robotics toolbox, the space trajectory planning and simulation of the robot model were done and the continuous varied trajectory curve was obtained. The results verify the correctness and rationality of the robot kinematics model. It provides a theoretical basis for further research and application of UR series robots.

Carbon fiber composites have been widely used in mechanical equipment because of its excellent properties such as light weight and high strength.One of the main factors that restricting hydraulic cylinder’s efficiency is the weight,and hydraulic cylinder is constitute of cylinder body,piston rod and seals structure,among which the most important part of mass reduction is hydraulic cylinder body.Therefore the solution of lightweight technology is by filament winding with carbon fiber composite to manufacture hydraulic cylinder,subsequently it is assembled with others part to form a carbon fiber composite hydraulic cylinder.The latest research progress of metal/non-metal lined cylinder and composite hydraulic cylinder at home and abroad were reviewed.The forming process of composite hydraulic cylinder was analyzed,and the effects of processing parameters on the hydraulic cylinder performance were illustrated.Finally,the development direction of lightweight hydraulic cylinder was pointed out.

Welding robot can greatly improve the working conditions of workers and increase productivity, and the key to ensure the quality of weld forming is to choose reasonable characteristic parameters for the welding robot.The influence of key characteristic parameters on welding quality in the welding process of welding robot was analyzed. The different parameters prediction methods and the parameters characteristics were analyzed and reviewed. The development trend of the characteristic parameters prediction methods for welding robot was prospected, and the future research direction was put forward.

Aiming at the problem of time optimal trajectory planning of six-degree-of-freedom manipulator, a 4-3-4 mixed polynomial interpolation trajectory planning algorithm based on improved particle swarm optimization was proposed.Adaptive inertia weight was adopted in the algorithm, it could adopt corresponding weights according to each stage of the search process, which was helpful to jump out of the local optimal trap and keep the diversity of particle swarm.Replacing the fixed learning factors in the traditional particle swarm optimization with nonlinear learning factors could effectively improve the convergence speed and solution accuracy of the algorithm.The simulation results in MATLAB show that the convergence speed of the improved particle swarm optimization algorithm is increased by 46%, the optimization accuracy is increased by 38%, and the trajectory planning time of the manipulator is shortened by about 36%, which fully proves the reliability and superiority of the trajectory planning algorithm.

By equipping NC machine tool with aprobe and corresponding measurement code, an on-machine measurement(OMM) system is formed.Using this technology, machining and inspection are integrated on a same equipment, so multiple clamping and repositioning errors can be avoided.The problems such as difficult modifying of rejected parts and long auxiliary time can be solved.Current research state and development of OMM were introduced, including OMM system development and application, compensation technology of probe pre-travel error and OMM system development with correction function.Finally, some key problems in the field which needed to be solved and improved in the future were stated.

The component feed screw can complete the actions of increasing distance, reducing distance, diverging, merging, lifting, undulating, turning of regular or irregular batch packaging containers. Based on SolidWorks software, the steering screw design of complex bottle type was completed by using the principle of generating method. The operation process was modeled, and the screw design of the new bottle could be completed by directly modifying the corresponding model. Through the comparative analysis of the rotational acceleration curve, a suitable rotational curve was provided. At the same time, modeling error and transportation stability were analyzed.

The working environment of the axial piston pump is harsh and the working conditions are complex,and the piston moves in a reciprocating linear in the piston cavity,bearing complex alternating stresses.Fatigue damage is one of its common failure forms.In order to analyze the fatigue damage of the piston pump and predict its remaining life to improve its safety and reliability,the fatigue damage analysis and life prediction method of the piston pump was proposed.The rigid-soft-liquid coupling model of the piston pump was established,and the joint simulation and analysis were carried out;based on the Miner fatigue cumulative damage theory,the fatigue damage cloud map and fatigue life cloud map of the piston were obtained by using ANSYS Workbench software and nCode module,and the weak parts of the fatigue damage of the piston pump and the remaining life were analyzed;finally,the effects of spindle speed,working pressure on fatigue damage and remaining life of the piston pump were explored. The results show that under typical working conditions,the fatigue life of the piston is about 7 448.8 h,which can basically meet the fatigue life requirements of the piston.

A numerical algorithm for solving the real-time forward solution of cable-driven parallel robots with redundant constraints was presented.The kinematics model of 6-DOF cable-driven parallel robot with eight cables was established, and its mechanism was parameterized, the cable length was calculated according to the principle of vector closure.The nonlinear positive solution equations were derived from the inverse solution equation.The initial pose of the motion platform was taken as the initial value, and the forward position solution was obtained iteratively by using the Dog Leg algorithm.The circular curve was taken as the trajectory of the motion platform.The real-time simulation results show that the algorithm can be used to complete the accurate forward solution of the position and attitude.The experimental results show that the average time of the five pose combinations is less than 0.07 ms, which meets the real-time requirements of solving the forward position and attitude solution of the cable-driven parallel robot.

Gearbox is the core component of wind turbines. The design of a fault simulation test bench for the gearbox has profound significance for the gearbox fault detection and diagnosis of wind turbine. The current situation of wind turbine gearbox test bench at home and abroad was descripted. Parameters required for the test bench were calculated by scaling based on the actual parameters of MW grade wind turbine. Using inverter control motor to adjust speed and adopting a mechanical flywheel to simulate real torque input and angular velocity input, the dynamic characteristics simulation to the wind turbine was achieved.

It is indispensable that that intelligent robots boast mobile operation and obstacle avoidance as the main technology. A mobile obstacle avoidance system of intelligent robots is developed, with ultrasonic sensor and single chip microcomputer (MCU) con-trol as the main technology, supported by Camel machine rotation, motor drive and power supply modules. The test results show that the control of steering engine rotation enables the sensor to detect flexibly obstacles from multiple positions, with a good obstacle avoidance performance to make sure the robot runs safely and stably, thus providing an effective means for the obstacle avoidance technology of in-telligent robots.

Positioning technology is a key issue for navigation control and path planning in robotics. The traditional positioning method is based on the global positioning system(GPS), which is difficult to complete accurate positioning and navigation functions. Positioning and navigation method that do not rely on GPS is currently research hotpot in the field of robotics. A point cloud information frame matching method based on radar acquisition was proposed.According to the improved position and attitude estimation algorithm of laser point cloud data, it was corrected and optimized in combination with nonlinear optimization to complete the precise positioning of the mobile robot in the unknown environment. Through the ROS robot operating system, an experimental platform was established, the improved algorithm was verified.It is proved that the robustness and positioning accuracy of the improved inter-frame matching algorithm corresponding to the mapping and positioning effect are better, which can meet the engineering requirements.

To solve the artificial feeding and discharging problems for batch processing of disk parts of belt pulley, an automatic feeding and discharging project for economical CNC lathe was put forward to improve production automation level. The mechanical structure was designed with SolidWorks software, which was based on CK6136-750 machine tool, including feed mechanism, dischar ging mechanism and blank impel mechanism. Combining pneumatic technology, PLC technology as well as sensor technology, automatic feeding and discharging control system was developed, which was loaded to CNC miscellaneous function system. And the full automation of feeding, machining and discharging is come true with operation of one-person-multi-machine, thus cost of production is lessened, the processing time is shortened as well as labor intensity is lightened. The feeding and discharging system has broad application background and market demand.

Based on the localization requirements of mobile robots in unstructured environments, the development history of mobile robot localization research was systematically reviewed. It can be divided into three stages, such as accumulation of experience, formation of theoretical framework and breakthrough of applied research. Three main contradictions driving the development of mobile robot localization technology were pointed out. The advantages and disadvantages of the algorithms used to solve the key problems were compared and summarized. The key research directions of mobile robot localization based on vision were prospected.

Aiming at the problems of traditional fault diagnosis methods, such as poor flexibility, low efficiency, poor scalability and single form of fault alarm information, a remote monitoring and fault diagnosis system based on mobile terminal was developed. The system could collect the running data of industrial robot in real time through Internet and uploaded it to the server. The working state of industrial robot could be viewed anytime and anywhere by using a smart phone to realize remote data monitoring and fault alarm. The results show that through this system, the flexibility of field data query is enhanced, the accuracy of fault diagnosis and the timeliness of field fault treatment are improved.

In order to solve the difficult machining problem of the inner spiral surface of double equal wall thickness stator of positive displacement motor in shale gas development,the numerical simulation model of the external high-pressure forming of the double equal wall thickness stator was established.The influence rules of the geometric size of the tube blank,the hydraulic pressure magnitude and springback on the forming quality of the stator were studied.The accuracy of the numerical simulation model was verified by experiments and 3D measurement.The results show that the tube blank geometry size is proportional to wall thickness,equivalent plastic strain,displacement,residual stress and clearance value.The forming hydraulic pressure of 150 MPa or above has almost no effect on the equivalent plastic strain and wall thickness.The springback of stator bulging area is greater than that of transition area and contact area.When the forming hydraulic pressure is 210 MPa and the inner diameter of the tube blank is 88 mm,the forming quality of the stator is the best.

The progress and working principle of micro-blasting surface treatment technology were introduced, and the effect of micro-blasting on the surface integrity and cutting performance of coated tools was analyzed. It is found that the micro-blasting can improve the surface roughness of the coated tool and the residual compressive stress on the surface of the coating, so the tool cutting performance is improved and its service life is prolonged. The effects of the micro-blasting surface treatment technology on the surface of coated tools were summarized, and the micro-blasting surface treatment technology was summarized. The results provide reference for surface treatment and green intelligent manufacturing of coated cutting tools.

The hydraulic rotary valve is a hydraulic component that can be used to realize the reversal of the oil circuit of the hydraulic system.It has the characteristics of controllable commutation frequency,especially in high frequency hydraulic excitation systems.There are many research achievements on the performance of hydraulic rotary valves.The structure innovation,hydrodynamic force characteristics,high frequency commutation characteristics and gap flow characteristics of hydraulic rotary valve were summarized,the related factors affecting the performance of hydraulic rotary valves were summarized,and the problems and further research directions of hydraulic rotary valves were put forward.

Hydraulic system is the core component of control and power transmission equipment.It is widely used in modern industrial production machinery.Improving the accuracy of hydraulic system fault diagnosis has important engineering significance such as improving engineering efficiency and ensuring work safety.Once faults occur,multiple faults occur at the same time,the traditional BP neural network fault diagnosis system cannot meet the diagnostic accuracy.A method of hydraulic system diagnosis was proposed based on genetic algorithm optimizing the BP neural network (GA-BP).Aiming at three typical fault modes of multi-sensor information fusion hydraulic system under different sampling frequencies,the comparative analysis was made.The results show that the GA-BP fault diagnosis algorithm has better diagnostic performance than the traditional BP neural network.

Domestic three-axis CNC machine tools have the problems of low accuracy and poor reliability, and the accuracy and reliability of the machine tools can be guaranteed by reasonable static accuracy design methods. The static precision design methods of machine tools include robust design methods of machining precision and static geometric precision design methods. Aiming at the problems of the coupling rationality of the two precision design methods and the low practicality of engineering applications, based on the in-depth investigation of the static precision design research results of machine tools, from the key problems of the machine tool volumetric error modeling, the geometric error element identification of linear axis, and the key geometric error element traceability, robust design of machining accuracy and static geometric accuracy design, the specific solutions were given respectively, and a complete set of implementation schemes of static accuracy design system for three-axis CNC machine tools was formed to improve the geometric accuracy design of machine tools.It provides reference for static geometric accuracy design of the machine tool.

Aiming at the low efficiency of existing mobile robot path planning methods, a path planning method based on improved fuzzy adaptive genetic algorithm was proposed. Based on domain knowledge, the feasibility of the initial path was screened to improve the proportion of feasible paths. Fuzzy logic controller was used to dynamically adjust the running parameters of genetic algorithm to improve the speed of path optimization and avoid falling into the local optimal path; the operation safety requirements of the robot was considered comprehensively, the cosine function smoothness evaluation factor was introduced, and different penalties were applied to different path angles to improve path smoothness. The simulation results show that the improved algorithm is effective to solve the path planning problem.

The main control points of wheel crane hoisting winding open hydraulic system and conventional closed hydraulic sys-tem control theory were discussed, and a new type of control technology was put forward for controlling wheel crane hoisting winding closed hydraulic system. The principle was that a balance valve was set in hydraulic system to solve start-stop sneak problems such as hook, impact vibration and etc, by using the balancing valve features. The balancing valve load safety features were used to avoid hydraulic system driving lines in case of burst or engine failure in the event of stall load fall. By balancing valve pilot inside and outside spreading, the problem of balancing valve fever in the closed hydraulic system was solved. Use proves that the designed QLY series wheel crane hoisting winch closed hydraulic system control technology is stable and reliable in performance.

Taking the five axis NAS cone test piece as the research object, the five axis post-processing file was generated by using CATIA software. The G code simulation verification was carried out by using VERICUT software, and the cutting correctness was verified by the CATIA post-processing on GS-200 Huazhong NC five-axis machine tool with AC double turntable structure. The correctness of the post-processing development for the Huazhong five-axis machine tool based on CATIA is verified.

In terms of lacking environmental awareness and autonomous path planning of snow cleaning robot in unknown environment, the designing idea of snow cleaning was confirmed through analyzing simultaneous localization and mapping(SLAM) based on robot operating system(ROS) combined with laser radar, and path planning technology.SLAM based on improved Rao-Blackwellized particle filter was applied to realize simultaneous localization and mapping of robots in unknown environments.Raster map was constructed through laser radar scanning and matching, A^* algorithm and DWA algorithm were used for global path planning and local dynamic obstacle avoidance in the established raster map, and the feasibility was verified with the independently developed snow clearing robot as an experimental platform. The experimental results show that SLAM based on laser radar effectively solve the pose estimation and map construction of snow cleaning robot problemin the actual environment. The snow cleaning robot can move according to the designated route and avoid obstacles real-time, which verifies the possibility of the designed snow cleaning robot.

A direct-drive turntable was designed and debugged with SIEMENS 828D CNC system. The causes of graduation error of rotary table were analyzed. Indexing accuracy of the rotary table was compensated by using pitch compensation function of SIEMENS 828D CNC system.

In order to reveal the complicated dynamic characteristics of a double chamber oil pneumatic shock absorber under dynamic excitation, the dynamic mathematical model and fluid-solid coupled finite element model of the double chamber oil pneumatic shock absorber were established respectively considered the gas-liquid two-phase flow, and the dynamic characteristics of the shock absorber under shock, sinusoidal and stochastic excitation conditions were compared and analyzed. The results show that the calculation results of the finite element model of double chamber oil pneumatic shock absorber are basically consistent with the mathematical model; the equivalent dynamic stiffness is nonlinear under the impact of large displacement; the equivalent dynamic stiffness varies with the excitation amplitude and frequency under sinusoidal excitation, and the amplitude change has a great influence on the equivalent dynamic stiffness of the shock absorb. By using the fluid-solid couped method, the internal complex flow field under high speed oil flow can be analyzed, which is closer to actual situation.

Based on the screw theory, the kinematics modeling for the 6R robot was carried out by means of the screw POE method. Based on this model, the inverse kinematics of the robot was solved. According to the configuration of the robot, a class of subproblem was proposed, that was, the two joints were parallel to each other and perpendicular to the third joint. The solution of this kind of sub-problem was deduced by using the screw theory and the known Paden-Kahan sub-problem. Based on the screw method, the velocity Jacobi matrix was deduced. On this basis, the singularity of the robot was analyzed, and the angle value of the singularity joint was obtained, which provided theoretical basis and important data for the trajectory planning and real-time control of the robot. The kinematics solution and singularity analysis were simulated by MATLAB. The simulation results show that the kinematic model is correct, the algorithm has high precision and the singularity analysis result is correct.

A direct drive volume control pressure model based on AMESim and Simulink co-simulation was established to solve the problems of motor delay, system dead zone nonlinearity, system overshoot and pressure fluctuation in differential cylinder conversion.The fuzzy PID controller was designed and compared with the traditional PID controller. Through simulation, it is verified that the fuzzy PID controller has good effect in solving problems such as motor delay, system dead zone, system overshooting and pressure fluctuation.