The motion characteristics of the 2 DOF(degree-of-freedom) scale-changeable pantograph leg mechanisms were analyzed, different designs for scale change were compared. A scale-changeable pantograph leg with a nonlinear length adjustment mechanisms was proposed. The length of the thigh and shank link could be adjusted with a single driver according to the nonlinear proportion relation. Thus, the scale could be changed while preserving the pantograph mechanism properties. The scale-changeable pantograph leg may change the scale without disassembling, adjust the foot working space and the carrying capacity of the robots.

The rivet cracks generated in joining high-strength steels using SPR were simulated through finite element model, and the effects of rivet crack depth, crack position, and crack quantity on the mechanics properties of steel-aluminum SPR joints were systematically investigated. Firstly, a 2D axisymmetric numerical model was established using LS-DYNA software to simulate the SPR processes, and the accuracy of the numerical model was validated by comparing experimental and simulated joint cross-profiles. Secondly, a 2D-3D finite element model generation method was employed to establish a 3D numerical model of SPR joints to simulate the mechanics properties of SPR joints. The fracture parameters of rivets were calibrated using LS-OPT software. The developed 3D numerical model of SPR joints could accurately predict the mechanics properties of SPR joints. The results of parametric study indicate that the mechanics properties of the SPR joints decrease with increasing crack depth and gradually increase as the external crack position moves downward, but the internal crack has minimal influence. When multiple cracks exist in the rivets, the mechanics properties of the joints depend on the weakest cracks and are independent of the quantity.

A single-pedal regenerative braking control strategy was proposed based on the accelerator pedal for electric vehicles used in coal mine trackless auxiliary transportation, aiming to significantly enhance the regenerative braking energy recovery rate and energy utilization efficiency. Theoretical modeling of the regenerative braking process was conducted based on vehicle braking dynamics and the law of conservation of energy. Considering the structural characteristics of the driving system and accelerator pedal of mine trackless auxiliary electric transportation vehicles, a regenerative braking torque solution model was established based on the accelerator pedal opening. Furthermore, to meet the requirements of high-intensity braking conditions, a regenerative braking torque calculation model was developed for the transition from the accelerator pedal to the brake pedal. The working principles of the control strategy during vehicle acceleration, coasting, and braking were sequentially analyzed. For typical driving cycle conditions, an actual vehicle test was conducted on a chassis dynamometer to evaluate the energy consumption economy of the single-pedal regenerative braking control strategy. The results show that the driving range increases by 41.65 km and 35.86 km under the NEDC and WLTC conditions, respectively. Comprehensive on-road test results demonstrate a smooth transition of regenerative braking torque during the switching between the accelerator and brake pedals, ensuring a seamless acceleration and deceleration processes for the entire vehicles. This paper lays a technical foundation for the optimized development of regenerative braking systems and contributes to the promotion and popularization of coal mine electric vehicles.

To study the actuation characteristics of soft actuators and their bionic applications, a soft foldable actuator was designed based on Kresling crease pattern by using a symmetrical structural form, which could achieve fast actuation, generate only axial contraction without torsion(single-degree-of-freedom linear motion), and had the features of large contraction ratio and strong load capacity. Based on the principle of work equilibrium and combined with the geometric theory, theoretical modeling and experimental research of the soft foldable actuators were carried out to explore its deformation characteristics. The results show that the theoretical and experimental results are basically in good agreement. The contraction ratio increases with the increase of vacuum pressure. Under the same vacuum pressure, the larger the load, the smaller the contraction ratio. At the same contraction ratio, the heavier the load, the greater the vacuum pressure required by the actuator. The influences of different parameters on the actuation performance of the actuators were further analyzed, within the adjustment range of different parameters, the smaller the wall thickness, the smaller the relative angle and the larger the side length of the actuators, the better its performance including the contraction ratio and the bearing capacity. Based on the above results, a tandem soft foldable actuators were optimally designed and was mounted on a bionic humanoid leg, which may realize different functions such as flexion and extension, running, kicking a ball, and adsorbing.

Based on the new discrete configuration and the principle of digital drive, the dynamic and static output characteristics of a digital piezoelectric stack actuator(DPEA) were studied under different digital coding modes. Secondly the internal mechanism of hysteresis reduction under digital drive, was explored, and described the hysteresis, creep and dynamics characteristics of the DPEA were combined with nonlinear dynamic mathematical modeling. Finally, digital on/off time control was proposed to eliminate the remaining hysteresis and further improve the positioning accuracy. Experimental results show that compared to traditional piezoelectric stacks, the hysteresis of DPEA is reduced by more than 66%. The proposed modeling method yields a root mean square error of less than 0.3889 μm within 10 Hz. The proposed digital on/off time control may effectively eliminate the residual hysteresis of the DPEA within 10 Hz. 

A new type of heavy-duty high-precision inertial friction welding machine moving fixture clamping mechanisms was designed to meet the high-precision welding quality requirements of typical parts of aircraft engines. The positioning error analysis of the moving fixture clamping mechanisms was carried out.  A theoretical model was established for the mapping relationship between the positioning component tolerance of a mobile fixture clamping mechanism and the positional error of the welded part, ignoring other influencing factors such as machine tool errors, positioning reference plane errors of welded parts, and errors caused by clamping forces and thermal deformation on the welding accuracy of welded parts, this error theoretical model was used to calculate the dimensional tolerance range of the positioning components of the mobile fixture clamping mechanism based on the required welding accuracy of a certain type of rotor, a mobile fixture clamping mechanism was designed based on the calculated tolerance range of positioning components and clamp the welded parts to complete the welding tests. The experimental results show that the maximum errors of coaxiality error, parallelism error, and axial shortening error are as 0.04 mm, 0.02 mm and 0.12 mm respectively, all error detection results meet the required welding accuracy(coaxiality error:0.06 mm; parallelism error:0.04/300 mm; axial shortening error:± 0.2 mm). It indicates that the tolerance range of each positioning component obtained through analysis is reasonable, and the error theoretical model has important theoretical guidance significance for the tolerance allocation of moving fixture positioning components in the design of heavy-duty inertial friction welding machines.

Functional analysis of complex mechatronic systems focused on the continuous physical transformations achieved by physical subsystems, and ignored the complex execution sequences among the physical processes controlled by software subsystems. In response to this challenge, a software-physical integrated formal functional representation and analysis method was proposed. First, the flow-based functional representation was extended to form a unified formal functional representation. Then, a rule-based function decomposition method was proposed to support the automatic decomposition of software-physical hybrid functions. A mobile robot system was used as a case to illustrate the proposed software-physical unified functional analysis processes.

 In order to optimize the configuration of the compliant mechanisms and the distribution of the piezoelectric actuators simultaneously and meet the manufacturing requirements, a topology optimization design method of the compliant mechanisms was proposed with embedded movable piezoelectric actuators considering the minimum length constraints. The independent point density interpolation model was used to describe the material distribution of the main structure, the level set function was used to characterize the embedded movable piezoelectric actuator of any shape, the structure indicator function was used to identify the solid and empty phase materials, and the filtering threshold technology was used to control the minimum length of the main structure. At the same time, non-overlapping constraints were established to ensure that the piezoelectric actuator did not overlap with the boundary of the design domains during the optimization processes. Maximizing the output displacement of the compliant mechanisms was used as the objective function, and a hybrid topological description model of independent point density interpolation and level set method was established. The method of moving asymptote(MMA) approach was used to solve topology optimization problems. Numerical examples demonstrate that the proposed method may effectively simultaneously optimize the main structure and the position distribution of the piezoelectric actuators, and meet the minimum length requirements.

The dipole magnet vacuum pipeline was critical equipment for the booster ring of HIAF. In order to attenuate the eddy current effect, reduce the gap of magnet, and decrease the difficulty of vacuum pipeline machining, the 3D-printed titanium alloy-lined ring wrapped in stainless steel with a thickness of 0.3 mm was created for fabricating a thin-wall chamber. The structural optimization of the titanium alloy-lined ring was carried out through simulation, and thin-wall chambers were fabricated for deformation testing and high-temperature baking testing. Evaluation of the outgassing performance of 3D-printed titanium alloy was completed. Ultimate vacuum tests were conducted before and after coating thin-wall chamber with Ti-Zr-V films, and a study of the effect of eddy current on vacuum performance was carried out. The results show that the stresses of stainless steel and titanium alloy are below the strength limit when the thickness of the titanium alloy-lined ring is as 4 mm, the width is as 11 mm and the spacing is as 15 mm. The deformation of the ring, with an arch height of 0.5 mm, is measured to be 0.78 mm, and the structure remained stable after 35 rounds of high-temperature baking at 250 ℃. The outgassing performance of TC4 titanium alloy and the ultimate vacuum performance of the thin-wall chamber meet the design criteria.

To obtain high-quality ring rolling surface morphology, improve shape accuracy and improve bearing service performance. GCr15 ring raceway was polished by force rheological polishing technology. The orthogonal experimental scheme was designed and the range of experimental parameters was confirmed. The effects of polishing speed, abrasive particle size and abrasive concentration on material removal rate(MRR) and surface roughness Ra were studied. The signal-to-noise ratio of the datum was analyzed, and the variance analysis method was used to obtain the influence weight of the processing parameters on the processing results, and the optimal processing parameters were obtained. The shape accuracy of the rings before and after the optimal parameter processing was compared, and the force rheological processing model was established to analyze the improvement mechanism. The polishing speed has the most significant effects on the MRR and surface roughness, and the abrasive particle size and concentration have relatively low effects. Under the optimal processing parameters(polishing disc speed 90 r/min, abrasive particle size 2.5 μm, concentration 6%) polishing 90 min, the value of surface roughness Ra decreases from the initial 322 nm to 12.982 nm, and the variance do not exceed 2.158 nm2. The roundness decreases from about 3.05 μm before polishing to about 1.67 μm. The simulation model reveales that the reason for the improvement of shape accuracy is that the protruding part is easy to form a higher MRR. Polishing the bearing ring raceway with the optimized force rheological polishing processes may improve the surface quality and shape accuracy of the bearing ring raceway effectively, and provide a feasible solution for high-quality processing to improve the service performance of the bearings.

Peak power constrained flexible job shop scheduling problem(PPCFJSP) model was established to address the challenges of increased work cycles and increased machine load in flexible job shop scheduling under the constraints of peak power in the workshops. The optimization objectives were to minimize the maximum completion time and the maximum machine loads, taking into account the constraints of peak power in the workshops. For better scheduling decisions, firstly, the problem was transformed into a Markov decision process, then, a scheduling framework combining offline training and online scheduling was designed for solving PPCFJSP. Secondly, a double dueling deep q-network based on priority experience replay(D3QNPER) algorithm was designed based on priority experience replay, and a ε- greedy descent strategy introducing noise was designed to improve the convergence speed of the algorithm, further enhance the solving ability and stability of the solution results. Finally, experimental and algorithmic comparative studies were conducted to verify the effectiveness of the model and algorithm.

Aiming at the DBO algorithms imbalance between global exploration and local exploitation capabilities and low solution accuracy in the calibrating processes for kinematics parameters of industrial robots, a multi-strategy fusion(MSFDBO) algorithm was presented based on local product of exponential(LPOE) kinematics model. Firstly, a kinematics parameter identification model was established based on the LPOE model. Secondly, Piecewise chaotic mapping and elite inverse learning strategy were used for population initialization to obtain a more uniformly distributed population, incorporating the exploration behavior of the osprey to enhance the global exploration ability of the DBO algorithm, and expanding the search range through the stochastic perturbation mechanism to reduce the possibility of the DBO algorithm falling into a local optimum. To test the performance of the algorithm, the search performance of the MSFDBO algorithm was experimentally evaluated using 12 benchmark test functions. The results show that the algorithm performs well in terms of optimization. The compensation of kinematic parameters was identifed and verified for four T6A-19 industrial robots. The experimental results show that the mean absolute position errors are reduced by an average of 85.47% and the root mean square errors are reduced by an average of 83.92%.

To achieve efficient, safe, and energy-saving operations of tracked robots under non-flat environments, an improved non-dominated sorting genetic algorithm Ⅱ（NSGA-Ⅱ) multi-objective path planning method was presented. Firstly, comprehensively analyzing the operational requirements of tracked robots under non-flat environments, a 2.5D grid environmental model was established. Secondly, short path length, low energy consumption, and high safety were selected as sub-objective criteria for path planning. Finally, the 8-domain Manhattan collision avoidance algorithm was employed to improve the grid selection method, avoiding collisions between robots and vertices. Additionally, the NSGA-Ⅱ algorithm introduced an elite replacement strategy to expand the population size, preventing the loss of excellent path genes and accelerating algorithm convergence. Compared to the multi-objective variable neighborhood search（MOVNS) algorithm, the proposed method plans paths with an average reduction of 9.02% in path length, an average energy savings of 18.36%, and an average decrease of 7.28% in danger rate, contributing to the enhancement of path quality under non-flat environments. 

A hexapod robot platform was established by emulating the structural configuration of an animal torso. An online adaptive motion controller was introduced, which achieved impedance control parameter online learning by mimicking the compliant joint motions of the human arm. Integrated with the existing virtual motoneuron system, the hexapod robot dynamically adapted walking gaits and sped online to cope with diverse complex terrains. The adaptive motion controller exhibited versatility in accommodating different tasks and unknown robot dynamics, enhancing trajectory tracking stability. Finally, through simulation models and physical testing of the hexapod robots, the results demonstrate the effectiveness of the proposed approach in enhancing the robots adaptability.

A grinding surface roughness measurement method was proposed based on SA-CNN for convenient and accurate prediction of roughness values on screw rotor surfaces after grinding. Through orthogonal experiments, the surface roughness values of screw rotors and corresponding surface images were obtained. After preprocessing including adaptive histogram equalization and unsharp masking, the images were used as training samples input into the SA-CNN model. The SA-CNN model was employed to predict the roughness values on the grinding surfaces of screw rotors and compared with the predictions of classical networks such as ResNet, AlexNet, VGG-16, basic CNN, and graph neural network (GNN). Experimental results show that the SA-CNN model achieves an average prediction accuracy of 95.24%, with an RMSE of 0.0706 μm and an MAPE of 7.4206%, outperforming the compared networks. Furthermore, the SA-CNN model exhibits fast convergence, high accuracy, and good robustness.

Based on the characteristics of octagonal structure in glass sponge and vascular bundle in bamboo segment, two kinds of bionic lightweight, high-strength and tough planar structures and corresponding tubular scaffolds were designed and prepared by DLP process. By combining simulation and experiments, the ultimate load, failure mode and energy absorption of bionic plane structures during compression were analyzed. Based on the experimental results of three-point bending mechanics properties and numerical simulation, the bionic plane structures with the best bending performance were selected, and the bionic light pipes corresponding to each plane structures were tested for bending performance. The results show that compared with the traditional honeycomb tube, the designed glass sponge light tube has stronger bending resistance, which verifies the reliability of the plane structure comparison results. The resylts may provide guidance and reference for the design and preparation of new lightweight high strength and toughness scaffolds.

The hematocrit of thrombus analogs were analyzed primarily, their mechanical properties and cutting effectiveness were studied. Different hematocrit thrombus analogs were prepared to investigate their mechanical properties through compression tests, and their cutting efficiency was studied using a thrombus cutting experimental setup. It is found that the stiffness of the analogs decreases with increasing hematocrit and storage time. Specifically, when stored in serum for 10 days, stiffness decreases by over 50%, whereas with saline storage over the same period, the decrease is around 30%. Additionally, thrombus analogs with hematocrits of 10% to 20% exhibite stiffness levels similar to samples of deep vein thrombosis. The experiments also indicate that increasing cutting speed within a certain range the fragmentation of the analogs is enhanced, but beyond a certain threshold, further increases in cutting speed does not significantly improve fragmentation. This paper provides valuable insights for the design and optimization of thrombectomy devices.

 In response to the difficulty of high-precision machining by in pipe robots, a high-precision grinding method was proposed for in pipe robots considering stiffness characteristics, taking the example of repairing and polishing the residual heights of the weld seams in the pipe. Firstly, based on the wheeled pipe machining robots, a finite element simulation model was established considering the stiffness characteristics of the pneumatic support devices, and the deformation relationship was obtained under different machining loads and poses. Secondly, a weld seam recognition method was established based on height features, and a cubic B-spline model was used to establish the parameter equation of the weld seam busbar, thereby a machining trajectory point generation method was proposed to integrate stiffness compensation; Finally, the effectiveness of the method proposed for polishing weld seams inside pipes was verified through robot prototype experiments. The results show that the method may accurately trim the seam residual height of about 1 mm to less than 0.2 mm, and the error between the average seam residual height and the design residual height after machining is less than 5%.

To investigate the mechanical properties of mining machine cables, a physical model of the MCP-0.66/1.14 3*95+1*25 cable was constructed, and a cable bending device was designed based on the cables actual movement conditions. Tensile tests provided the material parameters for the cable strands, which served as the initial conditions for numerical simulations. The simulations covered cables with different stranding pitch ratios, twisting directions, and control unit cross-sectional areas. The results show that the cable stress increases with the stranding pitch ratio. Considering manufacturing costs and mechanical properties, a pitch ratio of 6 is optimal for this cable type. For twisting directions, where R denotes right-hand and L denotes left-hand twists, the stress order is RLR>RRL>RLL>RRR. Three-layer parallel twisting tends to cause strand dispersion, making the RLL twisting method optimal for mechanical properties. The fatigue life of the control unit conductor increases with the cross-sectional area during linear movement but decreases with the cross-sectional area during bending. Bending tests conducted with a bending machine corroborated the simulation results, validating the accuracy of the numerical simulations. These findings offer new insights into the design and analysis of complex cable stranding structures and provide theoretical support for enhancing cable mechanical performance and lifespan.

 In order to quantitatively predict the changes of wheel tread profile, ABAQUS software was used to complete thermal-mechanical coupling finite element simulation to solve the transient temperature distribution, hardness distribution, thermoelastic and plastic strain of tread during braking. Based on Archard wear model, the ABAQUS subprogram was developed using Fortran language. Then, ALE technology and Umeshmotion subprogram were used to solve the dynamic change of wheel tread wear depth in the finite element model. Finally, the influences of plastic deformations and wear were combined to obtain the changes of tread morphology after cooling to room temperature. The results show that the contact states of wheel and rail are affected by the plastic deformations of tread and wheel and rail wear. Under the combined actions of wheel and rail wear, the wear area is like a step. Under the conditions of axle load of 25 t, initial speed of 100 km/h and braking distance of 600 m, the maximum depression depth of wheel-rail contact spot center is about 16 μm and the edge of wheel-rail contact spot is as about 5 μm due to the comprehensive effects of plastic deformation and wheel-rail wear.