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2024 IEEE International Conference on Control Science and systems Engineering, ICCSSE 2024

作者： Li, Delun Cao, Jianfei Chen, Yiliang Xie, Zongwu Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin China Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing China

ISBN: (纸本)9798331517199

In anticipation of future extensive lunar surface operations, lunar rovers are required to advance towards higher speeds and improved energy conservation. When traveling at high speeds on the lunar surface, the vehicle's energy expenditure is greatly amplified by the influence of the terrain, particularly in conditions where driving and steering are coupled. This paper proposes an energy-saving control strategy for lunar rovers that employs dynamic rear-axle torque distribution, with the goal of optimizing transient energy consumption during travel. To tackle the challenge of non-differentiable functions within the optimization objectives, we suggest using a zeroth-order gradient optimization method for resolution, dynamically constraining the range of control parameters to fulfill the dynamic torque distribution objectives as needed for the task. The energy-saving control effectiveness of the algorithm has been confirmed through simulation, demonstrating a minimum energy-saving ratio of at least 4%, which increases to over 11% as the speed level rises, offering a valuable technical solution for the energy optimization of lunar rovers. © 2024 IEEE.

关键词： Rovers

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The current feedforward compensation method for the cogging torque of permanent magnet synchronous motors 9

The current feedforward compensation method for the cogging ...

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9th IEEE International Conference on Cyber technology in Automation, Control and intelligent systems, CYBER 2019

作者： Xin, Liu Dong, Zhou Pei, Zhang Rui, Wang Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing100094 China

ISBN: (纸本)9781728107691

The cogging torque is the inherent characteristic of permanent motors with the cogging. The cogging torque reduces the stability of the motor, especially in the status of the low speed. A compensation method based on the current feedforward is proposed in terms with the function between the torque and Q-Current by the method of space Vector PWM of the permanent magnet synchronous motors. The relation equation between the cogging torque and the rotor angle is obtained by the experimental analysis. And then, the transfer function of the current closed-loop system is obtained by using the experiment data and the system identification method. The cogging torque compensation current is calculated by the forecast for the position of the rotor. The experiment results show that the presented method can effectively improve the stability of the motor speed. © 2019 IEEE.

关键词： Permanent magnets

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Lunar Rover's Path Tracking Control Strategy Using Zero-Order Optimization Method

Lunar Rover's Path Tracking Control Strategy Using Zero-Orde...

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2024 IEEE International Conference on Control Science and systems Engineering, ICCSSE 2024

作者： Cao, Jianfei Wang, Yaobing Yu, Jiyang Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing China Beijing Institute of Spacecraft System Engineering Beijing China

ISBN: (纸本)9798331517199

The development of lunar rovers is critical for human exploration of the lunar surface. These rovers will need to travel longer distances at higher speeds, and the efficient control of their paths is essential for mission success. Model Predictive Control (MPC) is a path tracking method with foresight and robustness, capable of predicting vehicle movement and solving optimization problems to minimize cost functions. However, the complexity of lunar environments necessitates simplified models, such as kinematic models, to reduce computational cost. The study proposes a special MPC method that uses zeroth-order gradient optimization to directly solve the nonlinear model and generate precise control commands, significantly reducing computational burden and meeting the computational cost requirements of lunar rover control. © 2024 IEEE.

关键词： Cost functions

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Long-life Design and Experimental Verification of Ball Screw for spacecraft Mechanism 7

Long-life Design and Experimental Verification of Ball Screw...

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7th International Conference on Electromechanical Control technology and Transportation, ICECTT 2022

作者： Zhang, Wenming Zhang, Yun Chen, Ming Zeng, Lei Gao, Sheng Jiang, Xufu Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China Beijing Satellite Manufacturing Limited Company Beijing China

ISBN: (纸本)9781510656659

The ball screw is a commonly used transmission component. When applied to the spacecraft mechanism, it is necessary to comprehensively consider space environmental factors such as on-orbit high and low temperature, vacuum, atomic oxygen, electron irradiation, single particle, ultraviolet and infrared irradiation. In view of the long-life application requirements of ball screws for spacecraft mechanism, the factors affecting the life of the ball screws are analyzed. Two design schemes are proposed according to the lubrication method of the ball screws and the material of ball for a ball screws of a certain spacecraft mechanism. The design scheme of ceramic ball + raceway sputtering MoS2 lubrication has been confirmed by the test. The design can work for no less than 7000 times under the specified load, which meets the requirements of the flight model on-orbit. Through the ball screw long-life test, it can be seen that the load capacity and service life of the solid lubricated ball screw are significantly reduced. In the development process of the spacecraft mechanism ball screw, a special life test must be carried out to verify whether the ball screw can meet the on-orbit requirements. © 2022 SPIE

关键词： Layered semiconductors

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Discrete Element Simulation of Durability for Bionic Wheels of Mars Rover 2

Discrete Element Simulation of Durability for Bionic Wheels ...

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2nd Spring International Conference on Defence technology, ICDT 2020

作者： Lin, Y.C. Yan, Y.P. Yuan, B.F. Liu, Y.F. Zou, M. Beijing Key Laboratory of Intelligent Space Robotic System Technology and Application Institute of Spacecraft System Engineering CAST Beijing100094 China Key Laboratory for Bionics Engineering of Education Ministry Jilin University Changchun130022 China

Four kinds of bionic surfaces (convex, scale-like, ribbed and concave shape) for Mars rover wheels were designed to improve wheel durability. A discrete element wheel-soil simulation system was developed, and three-dimensional discrete element analysis and soil bin tests were conducted. The results show that the masses of the convex and scale-like forms increased by 5.4% and 17%, respectively, and that the tangential cumulative forces decreased by about 40% and 70%, respectively. The wear mass decreased by 53% and 47%, respectively, compared with a prototypical wheel. The simulation shows that the durability increased significantly. The average tangential cumulative forces of the concave and ribbed shapes increased by more than 50%, and the wear mass decreased by 35% and 32%, respectively, compared with a prototypical wheel. The simulation shows that the results were not definitive. The analysis shows that the durability of the wheels can be improved via bionic optimization method. These results therefore provide a basis and reference for the design and optimization of the Mars rover's wheel surface. © Published under licence by IOP Publishing Ltd.

关键词： Wheels

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A novel space target-tracking method based on generalized Gaussian distribution for on-orbit maintenance robot in Tiangong-2 space laboratory

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Science China(Technological Sciences) 2019年第6期62卷 1045-1054页

作者： MO Yang JIANG ZhiHong LI Hui YANG Hong HUANG Qiang School of Mechatronic Engineering Beijing Institute of Technology Beijing 100081 China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing 100081 China Key Laboratory of Biomimetic Robots and Systems Ministry of Education Beijing 100081 China Institute of Manned Spacecraft System Engineering China Academy of Space Technology Beijing 100080 China

Accurate target tracking based on visual images is the key for intelligent robots to assist or replace astronauts to work in space station. However, the special space environment such as non-uniform illumination and high-energy particle radiation is a huge challenge, which may lead to complex noise coupling in vision image. This paper proposes a novel method for accurate target tracking, the essence of which is the Retinex image enhancement algorithm in CIELAB color space(LAB-GRetinex) and the generalized maximum correntropy Kalman filter(GMCKF) which are all based on generalized Gaussian distribution. The LABGRetinex algorithm chooses the CIELAB color space, which is closer to the human vision, as the processing color space, and the generalized Gaussian distribution can estimate the light image accurately, so the influence of non-uniform illumination can be reduced effectively. Meanwhile, the GMCKF algorithm adopts the generalized correntropy criterion based on the generalized Gaussian distribution to replace the minimum mean square error(MMSE) criterion to realize the optimal filtering effect under the complex non-Gaussian noise, which can improve the target tracking accuracy. Sufficient ground simulation experiments and application experiments in the Tiangong-2 space laboratory verify the effectiveness of the proposed algorithm which can track the target accurately in the special space environment and provide the precise pose information for on-orbit robot maintenance verification. This research lays a technical foundation for the application of intelligent robot in the construction and operation on space station in the future.

关键词： space robot LAB-GRetinex GMCKF target tracking

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Learning a faster locomotion gait for a quadruped robot with model-free deep reinforcement learning

Learning a faster locomotion gait for a quadruped robot with...

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2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Hu, Biao Shao, Shibo Cao, Zhengcai Xiao, Qing Li, Qunzhi Ma, Chao Beijing University of Chemical Technology College of Information Science and Technology Beijing100029 China Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing China

ISBN: (纸本)9781728163215

Quadruped robots have great agility, flexibility and stability, which enables them to walk through uneven terrain. Motion control of legged robots is always a difficult problem. Previous approaches mostly either use a predefined gait that results in clumsy and unnatural behavior, or use reinforcement learning approach to generate a gait strategy that needs longtime computation and elegant network design. In this paper, we present an effective approach that uses deep reinforcement learning with prior knowledge to optimize the gait of quadruped robot. By using a specific quadruped robot walking gait as a priori knowledge, this approach adopts the technique of distributed proximal policy optimization to optimize the search for better gait. The proposed approach does not require modelling of complex robots, and has good network convergence speed and learning effect. Simulation results demonstrate that our proposed approach converges faster than other deep reinforcement learning methods without prior knowledge. Besides, our achieved gait has higher speed that is 50% faster than the trot gait without optimization. © 2019 IEEE.

关键词： Reinforcement learning

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Resonance frequency prediction approach of lattice structure fabricated by selective laser melting

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Advances in Astronautics Science and technology 2022年第4期5卷 309-316页

作者： Zhou, Hao Jia, Heran Zeng, Huizhong Tu, Yonggang Li, Linli Zhang, Xiaoyu Lei, Hongshuai Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering China Academy of Space Technology No. 104 Youyi Road Beijing 100094 China Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures Beijing Institute of Technology No. 5 Zhongguancun South Street Beijing 100081 China

Lightweight structures composed of a closed shell and internal lattice infill are highly desirable in satellites on account of their superior specific stiffness and buckling strength, which are brought about by the sandwich effect. These lattice structures can be fabricated by various additive manufacturing techniques, such as selective laser melting (SLM). However, the sub-millimeter-scale shell thickness and lattice strut diameter of the fabricated structure often deviate from the designed dimensions and lead to noteworthy discrepancies between the resonance frequencies of the fabricated structure and those of the initial design model. In this work, a bracket structure for a satellite is designed via topology optimization-based lattice infill approach and fabricated using SLM. A resonance frequency prediction approach based on X-ray micro-computed tomography and the stiffness equivalence is then proposed. Vibration tests are conducted to obtain the resonance frequencies of the fabricated structure. The prediction errors of resonance frequencies for the first three modes are less than 1%, whereas that of the traditional approach based on finite element analysis is as large as 14%. © 2022, Chinese Society of Astronautics.

关键词： Additive manufacturing Geometric reconstruction Lattice structure Prediction approach Resonance frequency

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Research on obstacle detection and path planning based on visual navigation for mobile robot 4

Research on obstacle detection and path planning based on vi...

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2020 4th International Conference on Electrical, Mechanical and Computer Engineering, ICEMCE 2020

作者： Zheng, Yixiao Yan, Bixi Ma, Chao Wang, Xinyu Xue, Haoyang School of Instrument Science and Optoelectronic Engineering Beijing Information Science and Technology University Beijing China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China

Both obstacle and path planning are of significance for autonomous visual navigation of a mobile robot which is able to realize free movement and obstacle avoidance. In this paper, a scheme of obstacle detection which is based on binocular vision to identify obstacles is constructed and it is combined with improved A* algorithm for obstacle avoidance motion for mobile robot platform. First, a binocular vision system to detect the robot's perception of the environment is used and the visual information is obtained. Then a Gaussian filter is used to reduce the noise in the image, and the grayscale image is obtained through the binocular vision system. The gray scale map is matched with SAD (Sum of Absolute Differences) in order to obtain the disparity image with comparison. Second, the location information of the obstacle is extracted through the environmental depth information contained in the disparity image, and the improved A* algorithm is used as the path planning algorithm in this paper, which can modify the path of the planning error. Furthermore, the detection experiment of the robot visual obstacle avoidance system was established and the optimal path was obtained. The examples show that, the obstacle avoidance system can complete the task of obstacle detection and give a better path for the mobile robot. © 2020 Journal of Physics: Conference Series.

关键词： Mobile robots

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Optimized laplacian sparse coding for image classification 8th

Optimized laplacian sparse coding for image classification

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8th International Conference on Image and Graphics, ICIG 2015

作者： Chen, Lei Gao, Sheng Yuan, Baofeng Qi, Zhe Liu, Yafang Wang, Fei Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing100094 China Xi’an Jiaotong University Xi’an Shaanxi710049 China

ISBN: (纸本)9783319219622

Laplacian sparse coding exhibits good performance for image classification, because of its outstanding ability to preserve the locality and similarity information of the codes. However, there still exists two drawbacks during the Laplacian graph construction: (1) It has expensive computational cost, which significantly limits the applicability of the Laplacian sparse coding to large-scale data sets. (2) Euclidean distance does not necessarily reflect the inherent distribution of the data. To construct a more robust Laplacian graph, we introduce a local landmarks approximation method instead of the traditional k-nearest neighbor algorithm, and design a new form of adjacency matrix. Based on the Nesterov’s gradient projection algorithm, we develop an effective numerical solver to optimize the local landmarks approximation problem with guaranteed quadratic convergence. The obtained codes have more discriminating power compared with traditional sparse coding approaches for image classification. Comprehensive experimental results on publicly available datasets demonstrate the effectiveness of our method. © Springer International Publishing Switzerland 2015.

关键词： Codes (symbols)

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