In order to solve the problem of poor cooling effect caused by complex internal temperature field of motorized spindle, a water cooler system for motorized spindle cooling was designed. According to the analysis results of the thermal characteristics of motorized spindle, a water cooler cooling scheme was proposed, the relevant heat transfer parameters were calculated, and the temperature?velocity control model for the motorized spindle was established. Then, the finite element simulation of fluid cooling for motorized spindle was carried out by ANSYS Fluent software, and the simulation results were verified by the motorized spindle cooling experiment. By comparing the simulation results and experimental results, it could be seen that the maximum temperature of the motorized spindle motor stator decreased by 60% and the deformation of the shaft decreased by 70% after cooling. The results show that the water cooler system has a good cooling effect on the motorized spindle, which can provide a certain reference for the research of active thermal control technology of high-precision machine tools.

Aiming at the problems of traditional rigid picking manipulators, such as small scope of application, poor environmental adaptability and great damage to fruits and vegetables, a rigid-flexible coupling pneumatic soft picking manipulator for crabapple picking was designed. According to the characteristics and picking requirements of crabapple, the six-finger wrapped picking form was determined. Taking Longfeng fruit as an example, the bending angle calculation model for the soft finger of picking manipulator was established, and the bending angle of single finger was determined; the HY-E620 type silicone was selected as the material of soft fingers through the tensile contrast experiment of three kinds of silicone materials; the ABAQUS finite element simulation analysis of the influence of various structures on the bending performance of soft fingers was carried out, and the optimal structure was determined; the corresponding relationships between the bending angle and the output force of a single soft finger under different driving pressure conditions were measured by experiments, and the three-finger grasping experiment for various fruits under the driving pressure of 0.08 MPa was carried out, which verified the rationality of the soft finger structure. Finally, a six-finger wrapped pneumatic soft picking manipulator was trial-produced, and the picking experiments were carried out on crabapple, apple, pear and orange. The results showed that the designed picking manipulator could not only pick clustering crabapples containing 3?6 fruits with a success rate of 80%, but also pick apples, pears, oranges and other spherical fruits, which had a certain versatility, and could provide a new idea for the design and research of fruit picking manipulator.

PDC (polycrystalline diamond compact) bit is the main rock-breaking tool in oil and gas drilling field, which has the advantages of high abrasion, high rate of penetration and high rock-breaking efficiency. As a cutting unit, PDC cutter determines the rock-breaking performance of PDC bit. The purpose of PDC bit cutter arrangement is to determine the spatial position of each PDC cutter on the bit, so that the bit has excellent performance and reliable life when drilling and breaking rock. PDC bits designed based on different cutter arrangement technologies show different rock-breaking performance during drilling. Therefore, the PDC bit cutter arrangement technology has been widely concerned by scholars at home and abroad. At present, a large number of scholars have made corresponding research on the cutter arrangement technology of PDC bit since its birth, but there is still a lack of systematic summary. For this reason, based on the literature about PDC bit cutter arrangement technology at home and abroad in recent years, the development process of PDC bit cutter arrangement technology since its birth was summarized, mainly including the early cutter arrangement stage, the classical cutter arrangement stage and the modern cutter arrangement stage. Through analyzing and summarizing the development process of PDC bit cutter arrangement technology, it was pointed out that the cutter arrangement technology of PDC bit in composite PDC bit, compatible intelligent PDC bit, long-life PDC bit, force-balanced PDC bit, PDC bit under impact and vibration and PDC bit in special formation represented the future development trend. The research results can provide some reference for the subsequent research of PDC bit cutter arrangement technology, and are expected to promote the further development of PDC bit cutter arrangement technology.

Multi-functional small robots have broad application prospects. To meet different operational requirements, a small land-air deformable amphibious robot was designed, which could achieve efficient ground movement and avoid obstacles through takeoff flight. The robot adopted a dual-mode design, in which the ground mode adopted a two-wheel drive motion design, and the airplane mode adopted a four-rotor flight design. The switching between the two modes was realized through the support and extension of the robot tilting mechanism. In order to verify the motion performance of the robot, the whole robot model was established by SolidWorks software, the kinematics modeling for the robot was carried out, and the kinematics equation of the robot mode switching process was derived. Then, the robot servo output was simulated by MATLAB and the robot prototype mode switching experiment was carried out. The simulation results of the output torque were basically consistent with the measured results, with a range of 0-250 N·cm. Finally, the robot prototype was used to conduct ground movement and air flight tests, and its motion process was analyzed to verify the stability of the land-air motion and mode switching of the robot. The research results verify the effectiveness of the designed robot, and it has a long endurance, which can provide a reference for the design of land-air amphibious robots.

In order to meet the rehabilitation training needs of patients with lower limb motor dysfunction at different stages, a traction lower limb rehabilitation robot that could realize the training modes of lying and sitting postures was proposed in view of the single training mode of existing lower limb rehabilitation robots. Firstly, according to the motion mechanism and bionic principle of human lower limbs, a five-degree-of-freedom hybrid mechanism configuration was designed. Then, the kinematics model of the robot was established, and the forward and inverse kinematics solutions were calculated, respectively. Then, taking the workspace coincidence degree between the end of human lower limb and the end of robot as the objective function, the mechanism parameters of robot were optimized by the genetic algorithm, and the effective workspace ratio of human lower limb in the sagittal plane of the human-machine system was 0.71. Finally, three kinds of rehabilitation training trajectories including CPM (continuous passive motion), circular motion and spiral motion were planned, and a robot prototype was built according to the optimized mechanism parameters. Through motion capture experiments, the rationality of the robot structure design and optimization results and the correctness of trajectory planning were verified, which indicated that the robot could meet the rehabilitation needs of patients with lower limb motor dysfunction.

In order to provide high-precision force feedback to doctors in robot-assisted remote interventional surgery, a novel vascular interventional surgery robot with force detection mechanism is designed. It is a master-slave control system, including a convenient master device and a slave device for delivering guide wire/catheter. Firstly, the force detection mechanism of the vascular interventional surgery robot was designed to realize the accurate measurement of axial proximal force and the perception of radial clamping force. Then, based on the dynamics analysis of the vascular interventional surgery robot, a fuzzy PID (proportional integral derivative) controller with online parameter setting function was designed to improve the delivery accuracy and anti-interference ability of the slave device. At the same time, the step signal was selected to verify the fuzzy PID controller. Finally, the physical prototype of vascular interventional surgery robot was built, and the master-slave motion tracking experiment and the detection and evaluation experiment of axial proximal force and radial clamping force were carried out. The experimental results showed that the vascular interventional surgery robot had a motion tracking error of [?0.31, 0.25] mm, could detect the axial proximal force with an average error of 0.12 N, and could sense the radial clamping force of 0.47-4 N. The research results verified the robustness of the designed vascular interventional surgery robot and the feasibility of its force detection mechanism, which can provide a reference for the design and improvement of similar products.

The lower limb exoskeleton assisted robot has problems such as whether the human-machine joints match, and whether the active joint design meets the driving force requirements of human joint during motion. In order to solve these problems, based on the designed electro-hydraulic servo driven lower limb exoskeleton assisted robot, by simplifying it into a seven-link structure, the instantaneous dynamic model of swing phase and support phase were constructed by Newton-Euler method combining with the gait balance theory. Then, the angle data, velocity data of human motion under different gait phases and the robot structure parameters were substituted into the Newton-Euler dynamic iteration equations to obtain the theoretical driving torque of each joint of the robot. Finally, the ADAMS (automatic dynamic analysis of mechanical systems) simulation experiment and human-machine cooperative walking aid experiment were carried out, and the correctness and effectiveness of the constructed dynamic iteration equations were verified by comparing the peak driving torque of each joint of the robot. The results showed that using the Newton-Euler method to solve the driving torque of the lower limb exoskeleton assisted robot joint could provide important theoretical support for its structural optimization and control strategy formulation.

Aiming at the key issues in the overall development of snakelike robots, including material selection, structure design and motion realization, a new multi-joint snakelike robot was developed. This snakelike robot was composed of 11 two-degree-of-freedom orthogonal joints, which could achieve three-dimensional high biomimetic motion while ensuring flexibility. The basic gaits of snakelike robot such as meandering, wriggling and tumbling were designed by using the serpentine curve, and an improved obstacle surmounting gait was further proposed. At the same time, the gaits of the snakelike robot were simulated in the V-REP software, and the motion trajectories and efficiency of different gaits were compared. Finally, through the gait experiment of the snakelike robot prototype, the influence of each control parameter in the gait model on the motion waveform and speed of the snakelike robot was analyzed, and the reliability of the body structure and control system of the snakelike robot was verified. The research results have important theoretical significance and practical guiding value for realizing the gait planning and motion control of snakelike robots.

In order to ensure the operation economy and stability of mechanical vapor recompression (MVR) system, the matching characteristics of centrifugal vapor compressor and evaporator in the MVR system were studied. In view of the change of heat transfer coefficient of evaporator under new operation, operation and scaling conditions, the concept of temperature resistance characteristic curve of evaporator operation was put forward, and it was superposed with the temperature rise characteristic curve of centrifugal vapor compressor, so as to carry out matching analysis of centrifugal vapor compressor and evaporator. Through analysis, it was found that the design flow of centrifugal vapor compressor was too large or the heat transfer area of evaporator was too small, which would lead to insufficient matching and easy surge, thus affecting the operation stability of MVR system. However, the design flow of centrifugal vapor compressor was too small or the heat transfer area of evaporator was too large, which led to excessive matching, resulting in poor operating economy of the MVR system, and may even cause the MVR system to be unable to establish thermal self cycle. The results showed that the centrifugal vapor compressor had unstable surge during the startup of MVR system, and the unstable area could be avoided by temporary adjustment of system parameters or by taking auxiliary measures. The surge margin of centrifugal vapor compressor should be more than 20% and the design margin of heat transfer area of evaporator should be 30% during design; the deviation between actual evaporation temperature and design temperature during MVR system operation should be controlled within ±5 ℃. The research results can provide reference for the design and debugging of MVR system.

Aiming at the problems of insufficient automation and limited vision and observation angle of existing power tunnel inspection robots, a parent-child automatic inspection robot was designed. Among them, the master machine of inspection robot with mobile function could complete the main routine inspection work, and it had the ability to surmount and avoid obstacles; the slave machine with climbing function could complete the survey task under complex environment and extreme angle conditions. The slave machine and master machine could cooperate to complete the automatic inspection of the entire power tunnel. Firstly, based on the overall functional requirements, the specific form of each module of the inspection robot was proposed, and the hierarchical design of its automatic inspection logic system was completed. Then, the power tunnel operation environment was established in the ADAMS (automatic dynamic analysis of mechanical systems) software based on the virtual prototype technology, and the structure of the inspection robot master machine was optimized by combining the results of kinematic simulation analysis, so as to improve the stability of the robot operating in the tunnel and ensure that the sensors carried by the robot could work normally. The results showed that the inspection robot could run smoothly after the optimization of the master machine structure, the jitter amplitude of the sensor platform was within 5 mm, and all the sensors could work normally, which verified the rationality of the robot design. The relevant theoretical research results can provide reliable technical support for the development of the power tunnel automatic inspection robot physical prototype.

In order to make up for the deficiency of simulation ability and test accuracy of rotor airfoil dynamic test in high speed wind tunnel at domestic, based on the FL-20 continuous transonic wind tunnel, a method of dual-end synchronous driving rotor airfoil test model was proposed, and a dynamic test equipment for the high speed wind tunnel was designed. The equipment relied on the way of dual-balance dynamic load measurement combined with surface dynamic pressure measurement, which could improve the dynamic aerodynamic load measurement accuracy of rotor airfoil. The wind tunnel test results showed that: when the pitch oscillation amplitude of rotor airfoil test model was 10°, its oscillation frequency could reach 17 Hz, the test Mach number was 0.6, and the Reynolds number was 5×10⁶, which was at the international leading level. The developed dynamic test equipment and its related test technology have high reliability, and the test data is reliable and its law is reasonable, which has the ability to carry out high speed wind tunnel dynamic test. It can provide important technical support for the research of rotor airfoil dynamic stall and the simulation of real helicopter test parameters.

In order to solve the problems of poor wall adaptability and low movement flexibility of wall-climbing robots, the shortcomings of the existing magnetic adsorption mechanism of wall-climbing robots were analyzed. Taking a wheeled wall-climbing robot as research object, a wall adaptive pendulous magnetic adsorption mechanism was designed based on the functional requirements of wall-climbing robots. A comparative analysis was conducted between the pendulous magnetic adsorption mechanism and the traditional magnetic adsorption wheel by Ansoft software. In order to further reduce the mass of the magnetic adsorption mechanism and improve its adsorption reliability, based on the goal of high magnetic energy utilization, SNLP (sequential non-linear programming) algorithm was used to optimize the structural parameters of the pendulous magnetic adsorption mechanism. After optimization, the adsorption force of the magnetic adsorption mechanism was increased by 25.52%. A prototype of pendulous magnetic adsorption wheel was developed and the adsorption force testing experiment and demagnetization experiment were conducted. Motion performance testing experiment was carried after installing the pendulous magnetic adsorption wheel on a wall-climbing robot to verify the rationality of the optimization results of the structural parameters of the magnetic adsorption mechanism and the practicality of the structural design. The research results provide a reference for improving the working performance of wall-climbing robots.

In order to solve the problem of difficulty in testing and performance verification of compliant mechanisms in the process of optimal design, the mechanical properties of thermoplastic polyurethane (TPU) material were studied by 3D printing technology. The effects of material hardness and print fill rate on the mechanical properties of TPU material were analyzed, and the better 3D printing parameters of TPU material were obtained. Using single factor and two factor tset combined with variance analysis, the primary and secondary factors that significantly affect the flexibility of TPU specimens were identified as TPU material hardness and print fill rate. Combined with the mechanical property test data of TPU material, the mapping relationships between the material parameters and material hardness, print fill rate of four commonly used hyperelastic material constitutive models, i.e. Mooney-Rivlin, Yeoh, Ogden and Valanis-Landel, were obtained. The results showed that with the increase of TPU material hardness and print fill rate, the flexibility of the specimens decreased; among the four hyperelastic models, Ogden model has a good prediction effect on the mechanical properties of TPU specimens under different printing parameters; there was no significant difference in the predictive effect of the four models under the same TPU material hardness and different print fill rates. The research results can provide reference for 3D printing and finite element simulation analysis of TPU material, and provide reliable technical support for the test, performance verification and sample production of compliant mechanisms in the design process.

Aiming at the difficulties of status monitoring and predictive maintenance of complex mining equipment under harsh working conditions, a predictive maintenance system based on digital twin was proposed by combining various comprehensive modeling, analysis and prediction techniques, such as status monitoring, fault warning and predictive maintenance. Firstly, the design flow and construction principle of digital twin of complex mining equipment were introduced, and the function of predictive maintenance system was realized in the process of building digital twin. Then, the status data acquisition method based on the LabVIEW, MySQL and Unity3D was studied, and the Unity3D development engine was used to build a three-dimensional visual status monitoring platform for complex mining equipment, and the current equipment status was visualized through virtual space. Finally, the applicability of optimized BP (back propagation) neural network in the fault warning of complex mining equipment was analyzed. At the same time, the predictive maintenance model of key parts of complex mining equipment was established by MATLAB software, and the warning results were transmitted to the Unity3D development engine through MySQL database to drive and deploy the preset maintenance process, so as to achieve the fault warning of key parts under the real-time monitoring of equipment status. According to the actual maintenance process of shearer hydraulic system, a mixed reality (MR) predictive maintenance strategy was formulated, and the effectiveness of the hydraulic plunger pump of shearer rocker arm was verified by taking it as the experimental object. The results showed that the fault prediction accuracy of the proposed predictive maintenance system was higher than 90%, and the fault warning results could drive HoloLens glasses to achieve the maintenance interaction of virtual guidance, which verified the effectiveness of the predictive maintenance function of the system. The research results can provide new ideas for predictive maintenance of complex mining equipment.

In order to improve the walking stability of amphibious turtle inspired robot, a dynamics model was established, and a force/position control model was proposed based on the PID (proportional integral derivative) feedback control strategy. Firstly, according to the kinematics model of the robot, the transformation matrix and Jacobian matrix of the outrigger were obtained, and a force transfer model between foot end and hydraulic cylinder was established by the virtual work principle. Then, the Lagrange method was used to model the dynamics of the robot, and the dynamics equation of the outrigger was derived. At the same time, the dynamics simulation was carried out, and the real-time force on the foot end was introduced into the dynamics equation for calculation, which verified the correctness of the dynamics model. Finally, a hydraulic simulation model was built, and the robot motion simulation was carried out in the ADAMS?AMESim?MATLAB co-simulation environment. The simulation results showed that compared with the pure position control mode, the rotation of the robot knee joint under the force/position control mode was more stable, and the power output of the hydraulic cylinder was more stable and the power consumption was less. The research results have reference significance for improving the stability of robot motion, enhancing the robustness of motion control system and improving the overall efficiency of hydraulic system.

Compliant actuators can achieve safe interaction between robots and humans due to their inherent flexibility, and have strong environmental adaptability. To meet the requirements of exoskeleton robots for joint flexibility and variable stiffness characteristics, a reconfigurable variable stiffness compliant actuator was designed, which could achieve reconstruction by changing the geometric parameters, materials and quantity of elastic components, and achieve variable stiffness within an adjustable range by adjusting the radial preload. Firstly, based on the transmission principle of a zero-length frame four-bar mechanism, a stiffness mathematical model of the variable stiffness compliant actuator was established, and the influence of the number of flexible branches and the stiffness and preload of elastic components on the output torque and stiffness of the actuator was analyzed. Then, an ADAMS virtual prototype model of the actuator was established, and the statics performance simulation analysis was carried out to verify the correctness of the stiffness mathematical model. Finally, the dynamics model of the actuator was established and the transfer function of the dynamics system was obtained through Laplace transform. The frequency characteristics analysis results indicated that the stability of the compliant actuator was good. The designed compliant actuator had a small volume and small mass, which could be applied in the driving mechanism of wearable exoskeleton robots. The research results provide theoretical and technical references for the design of compliant driving joints in robots.

In view of the problem that the transmission accuracy of RV (rotate vector) reducer decreased due to the wear of its parts in the working process, a dynamic reliability model of the transmission accuracy of RV reducer considering the wear of cycloid wheel was established, the reliability of transmission accuracy was analyzed, and the tolerance of key parts and the modification parameters of cycloid wheel were optimized. Taking a heavy-load RV reducer as the research object, the wear depth of cycloidal gear was calculated by using Archard wear formula, the distribution of gear tooth profile wear was analyzed, and the wear amount was predicted by using Gaussian process regression model based on numerical simulation data; the reliability model of RV reducer transmission accuracy with dynamic wear was established, and its dynamic reliability was solved by Monte Carlo method; an optimization model was established with the dynamic reliability of transmission accuracy as the constraint condition, the minimum machining cost and the minimum maximum wear in the rated life cycle as the optimization objectives, and the optimal solution was obtained adopting multi-objective genetic algorithm. The results showed that after optimization, the wear of cycloidal gear was slightly increased, and the machining cost of reducer was obviously reduced; the reliability of transmission accuracy of the reducer had been significantly improved, and the reliability within the rated life of 6 000 h met expected requirements. The research results can provide reference for the design of high-precision RV reducer.

In order to achieve the topological optimization of the volume constraint and the minimum compliance of the continuous structure and solve the numerical instability problems, such as gray-scale element and checkerboard grid caused by classical variable density method, a new topology optimization method was proposed. Firstly, the method of improved solid isotropic material with penalization was used as the material interpolation scheme to establish a structural topology optimization model；secondly, the numerical instability problem was solved by introducing sensitivity filtering method based on the Gaussian weight function and designing a new gray-scale element suppression operator; finally, the optimization model was solved by the optimality criterion method. Through example analysis, it could be seen that the new strategy could improve the topology optimization method. The method had the advantages of faster convergence, acquisition of optimized structures with small compliance and good topological configuration and better suppression of gray-scale element generation. The results provide new ideas for the study of topological optimization of other continuum structures.

In the process of shale gas exploitation, the shale gas in the cylinder of the compressor host is rapidly compressed in a short time, resulting in high shale gas pressure and large fluctuation, and fast unit speed. As a result, the host is subjected to a variety of complex and periodic excitation loads, and the host and its components produce complex vibration, which seriously affects the working reliability of the compressor. Therefore, taking large reciprocating compressor host as research object, combining the transient response analysis with experimental test, the vibration research of the compressor host was carried out. The vibration simulation and test results of the host showed that the largest vibration deformation of the host was 0.09 mm at the end of the fourth cylinder; the maximum stress of the host was 29.66 MPa at the connection between the primary air intake buffer tank and the fourth cylinder; the vibration intensity of the free end of the secondary air intake buffer tank of the host in the reciprocating direction was the largest, which was 14.75 mm/s. In this state, the vibration intensity met the requirement, and the vibration of the host was in a safe state; the maximum error of vibration intensity obtained by simulation and test was 12.7%, which was within the allowable error range of the project, and verified the rationality and correctness of the simulation method. The research results provide a reference for further reducing the vibration and optimizing the structure of the compressor host.

In order to reasonably design the large deep-sea autonomous underwater vehicle (AUV), the static configuration problem of its unpowered spiral dive was studied, and the motion characteristics of its unpowered spiral dive were analyzed. Firstly, the dynamic model of large deep-sea AUV was derived based on the Lagrange equation and its direct route test, oblique towing test, cantilever pool test and plane motion mechanism test were numerically simulated by the CFD (computational fluid dynamics) software, and the corresponding hydrodynamic coefficients were fitted by the least square linear regression method; at the same time, the validity of the dynamic model was verified through comparing the route speed of this AUV under the given thrust condition. Then, based on the constructed dynamic model, the six-degree-of-freedom motion simulation model of large deep-sea AUV was established by using the MATLAB/Simulink and S-function, and the relationship between the net negative buoyancy, longitudinal displacement of gravity center, metacentric height and the unpowered spiral diving steady-state parameters was analyzed. Finally, a 1∶10 scaled-down prototype of large deep-sea AUV was designed, and the correctness of dynamic simulation results was verified by the pool test. The results showed that net negative buoyancy was the main power source of large deep-sea AUV, which determined the diving speed and yaw angular speed of the AUV; the greater the net negative buoyancy and the ratio of longitudinal displacement of gravity center to metacentric height, the faster the vertical diving speed of the AUV and the shorter the time to dive to a depth of 6 000 m; due to the large volume of this AUV, its longitudinal inclination angle was mainly determined by the ratio of longitudinal displacement of gravity center to metacentric height, and the influence of ballast mass on the gravity center position and moment of inertia could be almost ignored. The research results can provide a reference for the static configuration of large deep-sea AUV during unpowered spiral diving.

As an important spatial force sensing element, the six-dimensional force sensor is widely used in robot force/position control, grasping assembly, contour detection, autonomous obstacle avoidance and human-computer interaction. At present, improving the accuracy is one of the main research directions of six-dimensional force sensors. However, due to the influence of own structure and processing error and other factors, the six-dimensional force sensor will produce the interdimensional coupling phenomenon, and the interdimensional coupling is an important factor affecting its accuracy. In order to reduce the influence of coupling error, the decoupling algorithm of six-dimensional force sensor is studied by combining error analysis, theoretical derivation and experimental verification. Firstly, the coupling analysis of the six-dimensional force sensor was carried out, and its coupling model was obtained. Then, the linear decoupling algorithm of the six-dimensional force sensor was studied, and on this basis, the decoupling algorithm based on polynomial fitting was proposed to reduce the coupling error without changing the structure of the six-dimensional force sensor, so as to improve its accuracy. Finally, the orthogonal parallel six-dimensional force sensor was selected to carry out calibration experiments, and two algorithms were used for decoupling solution. The results showed that the decoupling algorithm based on polynomial fitting could reduce the influence of interdimensional coupling on the accuracy of six-dimensional force sensors. The proposed decoupling algorithm effectively improved the accuracy of the six-dimensional force sensor. Compared with the linear decoupling algorithm, the maximum coupling error was reduced by 8.914 percentage points and the linearity error was reduced by 0.111 percentage points. The research results can provide reference for reducing the coupling error and improving the accuracy of six-dimensional force sensors.

In order to accurately determine the ergonomics problems of products and improve the human-computer interaction performance, a conflict zone determination method based on functional surface drive and extension tools is proposed by using TRIZ (Teoriya Resheniya Izobreatatelskikh Zadatc). Firstly, the functional process model was improved by the functional surface to identify the initial problem functional elements of the ergonomics problems, and the transformation of the initial problem functional elements and the determination of the final problem functional elements were completed by combining the extension expression and correlation analysis. Then, the functional relationship model was improved by the functional surface to identify the initial conflict zone of the product, and the transformation of the initial conflict zone and the determination of the final conflict zone were completed by combining the extension expression, correlation analysis, implication analysis and superiority evaluation. Finally, the standard solution was used to solve the adverse effects in the conflict zone, and the evaluation and screening of the scheme were completed through the superiority evaluation. The feasibility of the proposed method was verified by an example of improved design of lawn mower. The research shows that this method is helpful for the determination of conflict zones in interactive products and can improve the efficiency of solving ergonomics problems.

During the operation of the warp knitting machine, its traverse mechanism may fail due to the out-of-control of traverse control system or the transmission error. In order to realize the effective fault detection for the traverse mechanism of warp knitting machine, a data-driven fault detection method was proposed by combining the combined features of vibration signals and the support vector data description (SVDD) algorithm. Firstly, the vibration signal of the traverse mechanism of warp knitting machine was collected and its time-domain features were extracted. Then, the energy proportion of the vibration signal in each frequency band was obtained by using the wavelet packet decomposition, and the feature vector was constructed by combining the time-domain features. Finally, based on the feature vector of the training samples (only containing normal samples), an independent closed minimum hypersphere was established based on the SVDD algorithm, and the state evaluation for the traverse mechanism of warp knitting machine was realized through comparing the distance from the test sample to the hypersphere center and the hypersphere radius. The fault detection results based on the proposed method were compared with the fault detection results using time-domain features and the SVDD algorithm, as well as using combined features and support vector machine (SVM). The results showed that the fault detection method combining combined features of vibration signals and SVDD algorithm had higher accuracy. The research results can provide a theoretical basis for the accurate fault detection of the traverse mechanism of warp knitting machine, and then provide certain auxiliary decision-making information for the warp knitting machine managers.

Spatial composite force measurement is one of the important development directions of spatial sensing technology. As a main spatial composite force measuring device, the six-axis force sensor is widely used in rocket engine thrust test, spacecraft docking and other fields. At present, lightweight has become one of the main research directions of six-axis force sensors. However, due to the large number of design indicators and mutual constraints among various indicators, the method of theoretical derivation, numerical simulation and experimental verification was adopted in the research. Firstly, the force mapping model of Stewart type six-axis force sensor under ideal conditions was established based on the spiral theory, and the structural parameters when the theoretical isotropy was optimal were determined by solving the comprehensive performance objective function. Then, the simulation model of Stewart type six-axis force sensor was built by using the ABAQUS finite element analysis software, and the mass, stiffness, strength and sensitivity of its initial prototype were analyzed in detail. On this basis, the influence of the main structural parameters of upper and lower loading plates on the mass, stiffness and strength of sensor was analyzed, the structural parameters of upper and lower loading plates were optimized, and a hemispherical weight reduction structure with regular tetrahedron characteristics was designed, which realized the lightweight design of sensor. Finally, the performance of optimized Stewart type six-axis force sensor was simulated and verified by experiments. The results showed that multi-objective parameter optimization combined with numerical simulation and experimental verification could effectively improve design efficiency and reduce design cost; the designed weight reduction structure could effectively improve the mass distribution of Stewart type six-axis force sensor and improve its mass utilization. After optimization, the mass of the sensor was reduced by 17.65% and its comprehensive performance was excellent. The research results can provide reference for lightweight design and comprehensive performance optimization of six-axis force sensors.

It is an important link to realize the safe production of coal mine to accurately identify the support state of the side guard and judge whether the side guard interferes with the shearer. This paper presented an anomaly detection method of side guard based on improved YOLOv5s, which set up a data set of side guard called hb_data2021 and improved the YOLOv5s model. It could be judged whether the state of the side guard was abnormal, according to the label classification based on the detection results of the improved YOLOv5s. In order to reduce the parameters of YOLOv5s model, MobileNetV3 and the lightweight attention mechanism NAM (normalization-based attention module) were used to replace the backbone feature extraction network. In order to improve the detection accuracy of side guard, the loss function was improved to α-CIoU and knowledge distillation was conducted. The experimental results showed that after distillation, the average precision of the network was improved by 1.0%, the parameters was reduced by 33.4%, and the reasoning speed was accelerated by 34.2%; the abnormal detection method of side guard based on the improved YOLOv5s had a good effect. It could be deployed on the NVIDIA Jetson Xavier platform to meet the requirements of real-time video detection. Transplanting the detection model to the embedded platform of the patrol robot can realize the abnormal detection of the side guard and meet the actual needs of the coal industry.