Abstract:

For inhibiting the joint load compensation torque jump caused by an unexpected joint failure when space manipulator executes the load carrying tasks, the optimization model and its solving process are proposed in this paper. The load compensation torque jump caused by the locked-joint failure is analyzed at first, and to minimize the torque jump at failure moment, the optimization model of the joint load compensation torque jump in the presence of the unexpected joint failure is established. The correction item of the joint torque containing the compensation coefficient and statics manipulability gradient is constructed and the optimal inhibition of the joint load compensation torque jump can be realized by fitting the optimal compensation coefficient function. Finally, the effectiveness of the proposed inhibition method is verified by the numerical simulation. The results show that the joint load compensation torque jump caused by the unexpected joint failure can be effectively inhibited by the proposed method, and the average inhibition ratio can reach up to 89.26%. Meanwhile, the accuracy of the operating force on the end-effector will not be affected, thus the space manipulator can finish the load carrying tasks stably and safely.

Key words:  Space manipulator, Load carrying tasks, Joint failure, Joint torque jump inhibition