空间机械臂在轨快换高精度模块化关节的研制

Design of Space Manipulator On-orbital Reconfigurable High Accuracy Modular Joint

研制了一种高输出力矩可实现高速比、高控制精度的在轨可维护模块化关节。首先对高负载空间机械臂进行了动力学仿真,计算出关节力矩需求。其次,确定直流无刷舵机串联谐波减速器的传动方案。直流无刷舵机本身的齿轮传动误差经过谐波传动可以忽略,又有效提高了速比;输出端谐波减速器使关节在满足力矩需求的同时,具有很高负载自重比和传动精度,整个关节的机械回差可控制在1 arc min以内。在机械精度得以保证的同时,设计了基于FPGA的空间机械臂关节硬件控制器,完成高精度传的感器信息采集处理以及关节的闭环控制,以达到3 arc min以内的闭环控制精度指标。另外,为保证此关节长期在轨服役需求,设计了在轨可更换功能以及在轨手动驱动功能;所有控制电路集成于关节内部,实现机电一体模块化,便于在轨整体拆换。最后以关节样机为实验对象,搭建关节负载-精度测试平台,通过PD控制得出关节闭环控制精度,验证了设计的正确性。

A newly designed space manipulator on-obital reconfigurable modular joint was described.The rated joint torque requriement was calculated based on the manipulator task dynamic simulation.The drive chain of the joint consisted of DC motor,gearbox,and harmonic drive giving the joint high weight/load ratio and high accuracy whose mechanical error is less than 1 arc min.A high accuracy joint control system was developed based on FPGA which could get accurate sensor information.The calbes go through the core of joint and the electronic board is mounted in the inner housing of joint.These features above give the joint a higher compactablility.The joint could be mounted or dismounted on-orbital which allows the manipulator service permanently on space.At the end,the performance of the joint prototype was tested on special testbed by using PD control.