针对航天器在轨精细操作应用需求,对螺钉旋拧工具进行了研究,设计了一种适用于空间机械臂自主旋拧螺钉的末端工具.该工具由机械臂末端关节电机驱动旋转,利用电磁铁对螺钉吸附、夹持和释放,通过复位弹簧的压缩和复位实现了对螺钉的随动而不需在旋拧过程中改变机械臂的整体位置和姿态,以臂上力矩传感器实时监测了拧紧力矩.提出了基于智能手眼相机识别与测量的柔顺自适应旋拧方法,并在地面仿真模拟操作中对测量精度和旋拧力矩进行了测试.试验结果表明:所设计的末端旋拧工具机械结构简单,易于操作控制,实现了设计功能,能可靠地对螺钉进行旋拧作业并合理控制拧紧力矩.
Aiming at the application requirements of the spacecraft on-orbit fine operation, the facility used to twist screws was investigated. An end effector was designed for a space manipulator twisting screws automatically. The effector was rotated by the manipulator's end joint motor, and an electromagnet was used to take up or put down a screw, which was allowed to move back and forth without changing the tolal attitude or position of the space manipulator by means of the compression and extension of the back-moving spring. The tightening torque was real-time monitored by the manipulator's torque sensor. A flexible adaptive method was presented to twist screws based on smart hand-eye camera recognition and measurement, the measurement accuracy and tightening torque were tested in ground-based simulated operation. The experimental results show that the end effector has simple mechanical structure and is easy to operate and control, it realizes the designed function and can be reliably applied for twisting screws operation while controlling the tightening torque appropriately.