Analysis and compensation control of passive rotation on a 6-DOF electrically driven Stewart platform

Abstract

Abstract. With the development of motor control technology, the electrically driven Stewart platform (EDSP), equipped with a ball screw or lead screw, is being widely used as a motion simulator, end effector, and vibration isolator. The motor drives the lead screw on each driven branch chain to realize 6-DOF motion of the moving platform. The control loop of the EDSP adopts the rotor position as a feedback signal from the encoder or resolver on the motor. When the moving platform of the EDSP performs translational or rotational motion, the lead screw on each driven branch chain passively generates a relative rotation between its screw and nut in addition to its original sliding motion. This type of passive rotation (PR) of the lead screw does not disturb the motor; hence, it cannot be detected by the position sensor attached to the corresponding motor. Thus, the driven branch chains cause unexpected length changes because of PR. As a result, the PR generates posture errors on the moving platform during operation. In our research, the PR on the EDSP was modeled and analyzed according to the geometry configuration of EDSP. Then, a control method to compensate for the posture errors caused by the PR was proposed. Finally, the effectiveness of the analysis process and compensation control method were validated; the improvement in pose accuracy was confirmed both by simulation and experiments.

Modeling and control system experiment of a novel series three-axis stable platform

“…The main function of the stable platform is to isolate the impact of the installation carrier movement or external interference, provide a stable working environment for the equipment installed on the stable platform by establishing a stable reference plane, prevent the target loss or positioning error caused by the installation carrier movement, and achieve accurate tracking and positioning (Huang et al, 2021;Kuseyri, 2016;Soltani et al, 2011;Li, et al, 2018). It is this function based on the stable platform that makes it play a very important role in human-robot interaction, industry, rehabilitation, and other fields (Dasgupta and Mruthyunjaya, 2000;Yang et al, 2022;Chen et al, 2016;Yu, et al, 2019;Hilkert, 2008).…”