As a new on‐orbit detection platform, the space robot could ensure stable and reliable operation of spacecraft in complex space environments. The tracking accuracy of the space manipulator end‐effector is crucial to the detection precision. In this paper, the Cartesian path planning method of velocity level inverse kinematics based on generalized Jacobian matrix (GJM) is proposed. The GJM will come across singularity issue in path planning, which leads to the infinite or incalculable joint velocity. To solve this issue, firstly, the singular value decomposition (SVD) is used for exposition of the singularity avoidance principle of the damped least squares (DLS) method. After that, the DLS method is improved by introducing an adaptive damping factor which changes with the singularity. Finally, in order to improve the tracking accuracy of the singularity‐robust algorithm, the objective function is established, and two adaptive parameters are optimized by genetic algorithm (GA). The simulation of a 6‐DOF free‐floating space robot is carried out, and the results show that, compared with DLS method, the proposed method could improve the tracking accuracy of space manipulator end‐effector.

Precision measurement technology and instruments are the basis for high-quality development in modern industry. With the specialization of supporting facilities, ultra-precision motion guidance has become a core technology to achieve ultra-precision measurement. Aerostatic bearings have the advantages of low friction and high precision, and are gradually playing an irreplaceable role in precision measurement and instruments. This paper summarizes and puts forward two contradictions for improving the loading capacity of aerostatic bearings, and investigates how to solve them via structural design. This paper analyzes the characteristics of the engineering calculation method, the gauge pressure ratio method, the gas resistance calculation method, and the AFVM (adaptive finite volume method) proposed. Finally, this paper summarizes the application scope of each method, gives solutions to the core problems, and outlines the developing trends.

To meet the requirement for the exact computation of rotational stiffness, this paper puts forward a mesh adaptation based analysis method for a compact multi-throttle aerostatic guideway and its constituent micro-structure. Contrary to previous methods that substituted or even ignored them, the dimensionless thickness pertaining to the depth of the micro-structure are restored and incorporated into each computational grids. The mesh adaptation procedures accept the dimensionless thickness as intermediate variable for the target mesh and apply local modifications to adapt the mesh to match the specified size. Then, the varying regularity of rotational stiffness by micro-structures can be studied by k-εC turbulence model when tilt. The tilt angle, although small, leads to a wedge-shaped film and then an uneven pressure distribution which have been also taken into consideration. Guided by the mesh adaptation method, a vertical compact guideway with high rotational stiffness of 7.22×103 Nm/rad is designed and manufactured for photolithography. Experiments verify its practical accuracy and effectiveness.

Ultra-precision measurement and manufacturing need high-precision machines, just as a photolithography machine needs air bearings. In gas lubrication, the use of compound restrictors with recesses has been widely proven to be an effective method to improve stiffness, which directly affects the accuracy of the machine. However, determination of the structural parameters of recesses is lacking in theoretical models. This paper has established a mechanical property model for a small-scale guideway, which can respond to the variation in force caused by micron-level changes in the recesses’ depth. To meet the requirements of high positioning accuracy and movement accuracy, this paper puts forward a high-stiffness guideway without an air tube. In order to improve rotational stiffness and determine the structural parameters of recesses, this paper found a guideway with the optimal gradient depth of recesses. Both AFVM (adaptive finite volume method) research and experimental results show that the gradient depth of recesses could significantly improve the rotational stiffness of guideways without air tubes.

Due to low friction and high precision, the aerostatic guideway is widely used in the field of high-end manufacturing and precision measurement, which is often used as a linear motion reference for multi-axis instrument equipment. However, in small-scale instruments and equipment, aerostatic guideways are rarely used. The main reason is that the gas film stiffness per unit area of the aerostatic guideway is low and it is difficult to ensure accuracy. In order to meet the high-precision measurement requirements of small modulus gears, this paper proposes a scheme for integrating the aerostatic guideway inside the probe. The difficulty of the research is the improvement of the stiffness and rotational stiffness of the small-scale aerostatic guideway. In order to achieve this goal, theoretical model establishment, simulation analysis, structural optimization, experimental verification, data processing and other aspects were studied. The experimental results show that the stiffness of the small-scale aerostatic guideway (cross-sectional area of 12 mm × 12 mm) is 2.86 N μm ⁻¹ , the rotational stiffness is 50.28 × 10 ⁵ Nmm rad ⁻¹ , and the load performance of the guideway per unit area is significantly improved.

Compared with electromagnetic motors, piezoelectric motors have the advantages of high torque, self-locking, and resistance to electromagnetic interference. According to the difference in working principle, piezoelectric motors are divided into ultrasonic motors and peristaltic motors. Currently, a kind of diamond-shaped oscillator ultrasonic motor for use in micro probes and a kind of anti-clamp peristaltic motor for use in spacecraft mass adjustment are being systematically developed by our research team. In order to summarize the experience and lessons learned, we conducted research on the principles, structures, and applications of existing piezoelectric drive motors, analyzed the advantages and problems of existing technologies, and developed a plan and expected indicators for completing this project. Finally, a report on the performance characteristics of different types of piezoelectric drive motors in terms of stroke range, speed, accuracy, and load capacity was summarized for reference.