Abstract: A force sensorless impedance control approach is proposed for the collision between the free floating space robot and the captured object by taking the dynamic parameters uncertainty into account. The contact force identified by the neural network and the other contact force observed by the inaccurate dynamic model are both employed as the estimated contact force between the end effector and the target object as well as the feedback of the impedance controller. The method enables the space robot to flexibly capture the service object even if the dynamic parameters are uncertain and the force sensor is not assembled. The numerical simulation results show that this method can effectively reduce the requirement for the precision of space robot dynamics modeling and is practical in engineering.

Key words: Space robot, Sensorless, Impedance control, Force estimation, On orbit capture