The mechanical equipment, due to its insufficient level of intelligence, is unable to perform complex operational tasks, and the mechanism for collaborative operation among the multiple machines is not clearly defined. Thus, by integrating edge computing, digital twin and multi-agent technology, a method for efficient multi-machine collaborative operation driven by the integration of edge computing and digital twin was proposed. Firstly, the terminal physical equipment Agent and the edge twin system Agent were constructed, and an edge-terminal cyber-physical symbiotic system applicable to various intelligent mechanical equipment was designed. Secondly, a dual-layer distributed collaborative operation mechanism was proposed, which was allowed both independent operation on an individual equipment and collaborative operation among multiple machines through direct physical interaction and indirect cyber-physical interaction. Finally, based on the existing equipment in the laboratory, the cyber-physical symbiotic systems for the detection robot and the operation robot were built. Through the robot collaborative operation experiment, the efficiencies of the cyber-physical symbiotic system and the dual-layer distributed collaborative operation mechanism were verified. The proposed method not only enhances the equipment's perception, decision-making and control capabilities, but also provides strong support for efficient multi-machine collaborative operation.

Biol-3D printing offers a new approach for treating skin injuries. However, the significant three-dimensional morphological heterogeneity inherent in native skin structures poses challenges for their precise replication using the existing methods. Therefore, this study integrated the Stewart parallel robot with the bioprinting technology to develop a dual-nozzle curved-surface skin printing system. Firstly, in order to obtain the workspace of the Stewart parallel robot, the inverse kinematics feasible region of the system was solved. By combining the constraints such as the lengths of the parallel robot's linkages, the rotation angles of the hinges, and the interference between the linkages, the printable angles and effective ranges of the moving platform of the parallel robot under different conditions were obtained. Subsequently, a simulation model of the printing system was constructed to validate the workspace analysis. By controlling the movements of 6 linkages, the kinematic solution of the system was solved, and the movement distance of the nozzle was obtained. Inverse solution calculation and positive solution simulation demonstrated the system's theoretical capability to print skin structures with a maximum angle of 26° and a maximum area of 142 mm × 134 mm. Then, using two types of GelMA hydrogels with two colors exhibiting favorable biocompatibility, the printing system was employed to print a bilaterally symmetric pentagonal star structure, a horizontal double-layer structure with a side length of 18 mm, and a curved-surface double-layer structure with an angle of 18°. Finally, in order to verify the functionality and practicality of the printing system, cell-laden printing was performed, and the survival rate and growth status of the printed cells were obtained. This research is expected to provide an effective method for printing real skin.

To enhance the accuracy and environmental adaptability of pose detection systems during the automatic assembly process of shield segments, a highly robust multi-source positioning method integrating line laser sensors and an RGB-D camera is proposed. At the perception level, five line laser sensors were employed to extract edge features of the segments, and the coordinates of the intersection points between arc edges and straight edges were derived in combination with the geometric model to estimate the segment pose. Meanwhile, a target system was designed, and the RGB-D camera was used to capture images and depth information of the segments. Through coordinate transformation, the spatial posture of the target relative to the assembly robot's end was obtained. In view of the limitation that a single type of sensor was vulnerable to environmental disturbances, an improved adaptive weighted fusion (IAWF) algorithm was proposed, which dynamically adjusted weights based on observation support and measurement variance, thereby achieving high-precision and high-robustness fusion positioning. Finally, the simulation was conducted to verify the stability and superiority of the IAWF algorithm under abnormal sensor conditions. Meanwhile, a fusion positioning experimental platform was established to evaluate the positioning performance of the IAWF algorithm under various working conditions, including normal, low-light, and abnormal line laser measurement scenarios. The results showed that the proposed fusion positioning method significantly improved the anti-interference ability of the segment pose detection system in complex environments while maintaining high measurement accuracy. The average position error was reduced by 28.4%, and the average posture error was reduced by 34.2%, which was superior to the measurement effect of a single type of sensor. The maximum misalignment and maximum gap during segment assembly were 4.8 mm and 4.6 mm, respectively, which met the actual engineering requirements. The research results provide theoretical foundations and technical support for the design of intelligent perception systems for the automatic assembly of shield segments.

Due to the inherent compliance and low stiffness of soft robotic arms, they exhibit complex morphological changes during spatial motion, making existing measurement methods inadequate for pose measurement of such robotic arms. To solve the above problems, a novel method combining binocular vision technology and B-spline curve fitting is proposed to accurately measure the geometric parameters of soft robotic arms. This method extracted the three-dimensional information of the central skeleton of the soft robotic arm through a binocular vision system and employed the cubic B-spline curve for three-dimensional shape reconstruction, thereby obtaining the key geometric parameters of the soft robotic arm. To validate the effectiveness of the proposed method, geometric parameter measurements were conducted on soft robotic arms with arc-shaped, S-shaped and L-shaped bends. The measurement results showed that the average bending curvature error of the robotic arm moving on a plane was 0.198%, and the average bending angle error was 0.159%. The average bending angle error of the robotic arm moving in three-dimensional space was 1.340%. In addition, this measurement method could be extended to dynamic measurements and accurately measure the geometric parameters of soft robotic arms even in the presence of visual occlusions. The measurement method based on binocular vision and B-spline curve fitting can provide a new idea for the parameter measurement of soft robotic arms.

To address the inefficiency and path redundancy in the path planning of composite robots in complex and unknown environments, a novel algorithm integrating an improved A* algorithm with the dynamic window approach (DWA) was proposed. Firstly, by introducing a dynamic inertia weight coefficient, the heuristic function of the A* algorithm was adjusted in real time to achieve acceleration in the early stage of the search and global optimal approximation in the later stage. Meanwhile, the time threshold mechanism for accessing Open List nodes was introduced to prevent the algorithm from falling into local optimal solutions. Grid maps with different sizes were constructed, and the improved A* algorithm was verified through simulation using MATLAB software. Secondly, the improved A* algorithm was integrated with DWA to achieve the synergy of dynamic obstacle avoidance and global path following. Finally, the improved A*-DWA fusion algorithm was experimentally verified in both the ROS (robot operating system) simulation environment and the real environment. The experimental results showed that, compared with the traditional A*-DWA fusion algorithm, the use of the improved A*- DWA fusion algorithm could shorten the planned path by 27.57%, reduce the turning points by 40%, shorten the time consumption by 31.03%, and make the speed variation of the composite robot more stable. The improving A*-DWA fusion algorithm not only has the performance of global optimal path planning, but also exhibits dynamic adaptability, enabling the robot to have a high success rate in obstacle avoidance and meeting the requirements of path planning for composite robots in complex and unknown environments.

Aiming at the problem of insufficient folding and unfolding ability and multi-mode adaptability of mobile robots in complex unstructured environments, a variable-diameter multi-mode mobile parallel robot composed of a variable-diameter platform and a 4-URU parallel mechanism is proposed. Firstly, a variable-diameter platform with multiple radial telescopic rods was designed based on the cam mechanism characteristics, and its structure and force characteristics were analyzed. Then, combining the telescopic characteristics of the variable-diameter platform, a multi-mode mobile parallel robot was constructed with the 4-URU parallel mechanism as the main body. The degrees of freedom of the 4-URU parallel mechanism were analyzed by spiral theory, and the degrees of freedom and switching methods under different motion modes were obtained. On this basis, the ZMP (zero moment point) theory was used to evaluate the stability of the robot in various modes. Finally, the obstacle-crossing performance and stability of the robot in narrow-slit crossing, single-loop rolling and dual-wheel obstacle crossing modes were verified through ADAMS simulation and prototype experiments. The results show that the designed mobile parallel robot has good folding and unfolding ability and multi-mode adaptability, which can provide a new solution for the design and application of multi-functional mobile robots in complex environments.

The 3-P(2-SS) parallel robot driven by three parallel and coplanar prismatic pairs is more suitable for operation in narrow and long areas compared to the traditional configurations. For this robot, its kinematic equations and Jacobian matrix were established, and the multi-solution nature of the kinematic equations was analyzed. By using the kinematic equations and the screw theory, it was confirmed that under normal working conditions, the robot's moving platform always had only three translational degrees of freedom, thereby simplifying the robot's kinematic equations and Jacobian matrix. The dexterity of the robot was analyzed using the condition number of the Jacobian matrix. The robot exhibited better dexterity when the sliders on both sides were located on the same side of the moving platform; the robot's dexterity deteriorated when it was near the singular points and the boundaries of the motion range. A robot dynamic model was established based on the Lagrange equation. The issue of dynamic uncertainty caused by the local degrees of freedom of the link was resolved using the minimum angular velocity assumption, the problem of the non-constant inertia tensor of the ink relative to the static coordinate system was addressed through transformation of the moving coordinate system, and the robot dynamic equation was obtained. By comparing the results of the dynamics calculation and motion simulation, the correctness of the dynamic equation was confirmed, with the error in the driving force calculation results caused by the minimum angular velocity assumption being within an acceptable range. The research results indicate that the 3-P(2-SS) parallel robot with coplanar parallel driving pairs has excellent operability, and the proposed dynamics modeling method provides a theoretical foundation for the construction of control systems for this type of robot.

Due to the relatively large length of the gear transmission chain and self weight of the nuclear related operation robot, in order to evaluate the end deformation of the robot caused by self weight and load for design optimization and deformation compensation, it is necessary to study the stiffness and end deformation of the robot. Firstly, by analyzing the structure and transmission principle of the nuclear related operation robot, based on the D-H (Denavit-Hartenberg) method, a robot linkage coordinate system considering joint bias was established, and a robot kinematic model was established. Secondly, in response to the joint torques and end deformation under the self weight and load, a solution method was proposed that treated the robot's transmission joints as flexible components to calculate the joint torsional stiffness, and calculated the robot's linkage stiffness based on the Bernoulli-Euler beam assumption theory. The robot's end deformation model was comprehensively obtained. Finally, the robot's end deformation was simulated and analyzed using the finite element method, and the accuracy of the proposed end deformation model was verified through testing.The proposed end deformation modeling method of the robot has certain reference value for the design optimization and end deformation compensation of the robots.

Aiming at the problems such as low operational efficiency and mechanical fatigue damage caused by impact and vibration in traditional manipulators during task execution, a multi-objective trajectory optimization method based on an improved sparrow search algorithm (SSA) is proposed. Taking the six-degree-of-freedom AR4 manipulator as the research object, its kinematic model was constructed by using the segmented 3-5-3 polynomial interpolation method. Then, based on the newly improved SSA (NISSA) that integrated Tent-Logistic chaotic mapping, improved elite opposition-based learning strategy and Cauchy-Gaussian mutation strategy, the multi-objective collaborative optimization was carried out for the operation time and impact of each joint of the manipulator. Finally, comparative experiments were conducted with other optimization algorithms to verify the effectiveness of NISSA. The experimental results showed that after optimization with NISSA, the operation time of the manipulator was shortened by 17.8%, and the impact generated during operation was reduced by 12.9%. The research results provide an efficient method for the trajectory optimization of manipulators.

Aiming at the common problems of limited driving frequency and insufficient output stroke in two-dimensional piezoelectric precision motion stages, a novel two-dimensional piezoelectric precision motion stage is designed by integrating a coordinated enhancement strategy of frequency response characteristics and output stroke with the lever-type amplification mechanism. Firstly, a quantitative analysis was conducted to investigate the influence of flexure hinge configurations on the displacement amplification performance, and an integrated statics/dynamics model of the precision motion stage was established based on the matrix displacement method. Then, in view of the improvement requirements for displacement output and dynamic response characteristics of the precision motion stage, starting from the dimensional parameters of flexure hinges, the key design variables were sorted and optimized by combining sensitivity analysis and constraint optimization methods. Meanwhile, the finite element simulation for the displacement amplification ratio and natural frequency of the precision motion stage was carried out using the ANSYS Workbench software. Finally, the accuracy of the integrated statics/dynamics model of the optimized precision motion stage was validated through experiments. The experimental results showed that the first-order natural frequency of the precision motion stage was 2 123 Hz, with a relative error of 2.256% compared to the simulated value of 2 172 Hz. Across varying input displacements, the average displacement amplification ratio was 2.771, with a relative error of 7.910% compared to the simulation results. When the input voltage was 120 V, the precision motion stage achieved an input displacement of 9.620 μm and an output displacement of 28.805 μm, and the corresponding displacement amplification ratio was 2.994, with a relative error of 0.499% compared to the simulated value of 3.009. The designed precision motion stage exhibits excellent displacement amplification performance and rapid response characteristics, and has a relatively compact structure, thus possessing certain practical application value.

Aiming at the problems of fixed stiffness and damping coefficients and suboptimal vibration suppression performance of traditional hydraulic dampers, a variable stiffness and variable damping magnetorheological (MR) damper is designed. By integrating two springs with different stiffness coefficients in series and parallel with the MR damper, the continuous adjustable stiffness and damping force can be achieved. Firstly, the working principle of the variable stiffness and variable damping MR damper was expounded, and its damping force mathematical model and dynamics model were established. Subsequently, a multi-objective optimization design targeting adjustable stiffness range, output damping force, and its adjustable range was conducted using NSGA-Ⅲ (non-dominated sorting genetic algorithm-Ⅲ). Meanwhile, simulation analysis and performance comparison were conducted on the MR dampers before and after optimization. The results showed that when the applied current was 2.0 A, the optimized output damping force reached 1 188.2 N, which was 29.5% higher than that before optimization. The adjustable damping force coefficient was increased from 4.1 to 4.6, and the adjustable stiffness coefficient was increased from 3.2 to 5.3, which increased by 12.2% and 65.6% compared with before optimization, respectively. The stiffness and damping performance of the optimized MR damper was significantly improved. The designed variable stiffness and variable damping MR damper features a compact structure while maintaining continuously adjustable stiffness and damping coefficients, which can provide reference for the design and optimization of MR dampers in vehicle suspension or building vibration isolation system.

Aiming at the problems of excessive weight and inconvenient use of large-load insulating pull rods for ultra-high voltage, a multi-objective optimization method for the end of insulating pull rods is proposed to reduce weight and enhance insulation performance and mechanical properties. Firstly, a finite element simulation model of the insulating pull rod was established, and the electric field distribution and mechanical characteristics of its end were analyzed. Then, based on the optimal Latin hypercube sampling experimental design method and the radial basis function neural network, the surrogate models for the mass, maximum stress, maximum deformation and maximum electric field intensity of the insulating pull rod end were constructed. On this basis, the MOMVO (multi-objective multi-verse optimization) algorithm was utilized to conduct multi-objective optimization design. During the optimization process, the multi-objective optimization performance of the MOMVO algorithm was improved by combining the Sine-Tent-Cosine chaotic mapping strategy, the sine cosine algorithm, and the adaptive parameter update strategy. Finally, the feasibility of the multi-objective optimization design method was verified through simulation and tests. The results indicated that the optimization performance of the improved MOMVO algorithm was superior to that of the traditional NSGA-II (non-dominated sorting genetic algorithm-II) and MOEA/D (multi-objective evolutionary algorithm based on decomposition). Compared with before optimization, the maximum stress, maximum deformation and maximum electric field intensity of the optimized insulating pull rod end decreased by 17.03%, 6.85% and 5.58%, respectively, while the mass decreased by 10.66%. The research results provide reference for the comprehensive optimization design of insulating tools and equipment.

In response to the issues of the short window period for tunnel maintenance in operational railway, the low efficiency of manual scabbling, and the lack of directional specialized equipment, a dedicated scabbling device for tunnel maintenance has been developed based on the construction requirements of tunnel renovation. Firstly, according to the scabbling operation requirements, the structure of the scabbling device was determined as a robotic arm combined with a scissor lift frame, and the fixed-connection and articulated scabbling mechanisms were designed. Then, the kinematic model of the scabbling device was established by improved D-H (Denavit-Hartenberg) parameter method for forward and inverse kinematic analyses, and the workspace of the scabbling device was solved by using the Monte Carlo method. Finally, the motion trajectory planning analysis for the scabbling device operation process was performed. The fifth-degree polynomial interpolation method was applied for the point-to-point trajectory planning in joint space, and the planar circular interpolation method based on the S-curve acceleration and deceleration control algorithm was used for the designated path planning in Cartesian space. The results showed that the overall structure and workspace of the designed scabbling device met the design requirements, and this device performed well in terms of motion. Through the motion trajectory planning analysis, the motion impact and vibration during the scabbling device operation process were effectively reduced, which ensured the safety of the scabbling operation. The research results provide a theoretical foundation for the subsequent physical scabbling device prototype manufacturing and scabbling operation testing.

In order to achieve rapid and efficient full-section one-time forming of rectangular roadways, it is imperative to develop a full-section rectangular roadheader. For this purpose, by combining numerical analysis and motion trajectory simulation, a Reuleaux triangular cutterhead driven by an eccentric shaft planetary gear was designed for the full-section rectangular roadheader, and the test prototype was developed to conduct experimental study on the process of the cutterhead cutting into rock samples, achieving the one-time cutting and forming of a rectangular full-section by a single cutterhead. Firstly, the forming principle of rectangular cutting for the designed cutterhead was analyzed, and the perimeter and area difference rates between the vertex trajectory and the standard square were obtained. Then, in order to study the cutting characteristics of the cutterhead during the process of cutting into rock samples, a full-section rectangular cutting test bench was built, and cutting tests were conducted on the central fishtail cutter and edge cutting tool during the process of cutting into rock samples. The experimental results indicated that during the process of cutting into rock samples with the central fishtail cutter, the propulsion oil pressure, cutting torque and Y-direction vibration all showed a fluctuating increase, and their fluctuation positions were basically the same. In the low propulsion speed range (v=3?5 mm/min), as the propulsion speed increased, the growth rate of propulsion oil pressure, cutting torque and Y-direction vibration increased rapidly. In the high propulsion speed range (v=5?14 mm/min), as the propulsion speed increased, the growth rate of propulsion oil pressure, cutting torque and Y-direction vibration slowed down. Among the vibrations in the X, Y, and Z directions, the Y-direction vibration was the most representative. During the process of cutting into rock samples with the edge cutting tool, the propulsion oil pressure increased with fluctuations, but the cutting torque decreased with fluctuations due to the collaborative rock breaking of multiple tools. When the same tools cut into rock samples, the greater the strength of rock samples, the greater the cutting torque and propulsion oil pressure required by tools. When different tools cut into rock samples, the difference in cutting torque was relatively large. The average vibration generated during the process of cutting into rock samples by edge cutting tools was smaller than that of central fishtail cutters. When the compressive strength of the rock sample was 6.515?15.639 MPa, the propulsion oil pressure required to achieve full-section rectangular cutting was 3.443?3.662 MPa, the cutting torque was 44.440?49.545 N·m, and the generated Y-direction vibration acceleration was 0.006 5?0.018 0 m/s2. The research results verified the feasibility of rectangular cutting by eccentric shaft planetary gear-driven Reuleaux triangular cutterhead in practical engineering applications, which lay a foundation for the development of full-section rectangular roadheader prototypes.