Hybrid Position/Force Control of Robot Manipulators Based on Second Derivatives of Position and Force
Satoshi Komada*, Muneaki Ishida*, Kouhei Ohnishi**
and Takamasa Hori*
* Faculty of Engineering, Mie University, 1515 Kamihama-cho, Tsu, Mie, 514 Japan
** Faculty of Science and Engineering, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama, Kanagawa, 223 Japan
This paper proposes a new robust hybrid position/force control of robot manipulators. The proposed method controls the second derivatives of control variables, such as position and force in a task coordinate system, in order to realize robust and high response control. To this end, the disturbances are estimated by a position-based disturbance observer and a force-based distrubance observer in the task coordinate system, and are compensated by feeding back the estimated distrubances. The proposed method requires less computational effort and is robust against the disturbance and parameter variations. The position-based distrubance observer has been proposed to linearize robot manipulators and has realized robust position control. However, when force control is performed, the force response is influenced by not only the nonlinearity of robot manipulators but also the charactersitics of the environment on which the force is imposed. Therefore, the force-based disturbance observer is developed to realize robust force control. A controller robust against the disturbance and parameter variations is realized by using the position-based disturbance observer and the force-based disturbance observer on performing the position control and the force control respectively. The effectiveness of the proposed method is shown by experiments by using a direct drive robot.
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.