Abstract: An impedance control method in which the impedance parameters can be adaptively changed according to the environment is proposed oriented to compliance control of space manipulators in contact with environment when the environmental stiffness and damping change abruptly or gradually. The least square method is used to estimate the environmental damping and stiffness. By analyzing the system characteristics of the space manipulator collided with the environment, a second order system in which the environment and the manipulator are regarded as one is deduced. Based on the response characteristics of the second order system, an adaptive scheme of impedance parameters self adjusting with the environment is proposed. Finally, a numerical simulation is carried out on a planar 2 DOF manipulator. Compared with the traditional impedance control method, the proposed adaptive impedance control has certain advantages in force control accuracy, reducing the maximum contact force and adapting to different contact environments.

Key words: space manipulator, compliance control, adaptive impedance control, least squares method