Abstract: Aiming at the lunar soil sampling mission in deep cryogenic and low-gravity environment of the moon, a four-degree-of-freedom rope-driven robotic arm with low power consumption, light weight, simple structure, and high reliability was designed and developed. The driving rope was installed at the end of the arm to greatly reduce the power consumption of the robot arm. Torsion springs were installed at joints 2 and 3 to provide more than 20N downforce to the end of the robot arm by spring torque. The fitting gap of different materials were matched to improve the reliability of the robot arm in deep cryogenic environments. A kinematics model of the robot arm was established, and the correctness of the kinematics model was verified. The simulation results of the sampling path show that the robot arm may achieve the sampling task. The semi-closed-loop control strategy was used to conduct position step tests and sinusoidal trajectory tracking tests on each independent joint of the prototype. The test results show that each joint has high response speed, good stability, and trajectory tracking capability. 

Key words: lunar environment, spring recovery, rope-driven, position step test, trajectory tracking test

摘要： 针对深低温、低重力环境的月壤采样任务，设计并研制了一种功耗低、重量轻、结构简单、可靠性高的四自由度绳驱机械臂。将驱动绳索安装在臂杆末端，较大程度地减小了机械臂的功耗；在关节2、3处安装扭转弹簧，通过弹簧扭力给机械臂末端提供超过20 N的下压力；针对深低温环境，匹配了不同材料的配合间隙，提高了机械臂的可靠性；建立并验证了机械臂运动学模型的正确性。采样路径的仿真结果表明机械臂可完成采样任务。采用半闭环控制策略对样机的各独立关节进行了位置阶跃试验和正弦轨迹跟踪试验,试验结果表明各关节具备较高的响应速度、良好的稳定性和轨迹跟踪能力。

关键词: 月球环境, 弹簧回复, 绳驱动, 位置阶跃试验, 轨迹跟踪试验