Robust hitting with dynamics shaping

Abstract

The present paper proposes the motion planning based on "the dynamics shaping" for a robotic arm to hit the target robustly toward the desired direction, of which the concept is to shape the robot dynamics appropriately in order to accomplish the desired motion. According to the linear system theory, the positional error of the end-point converges onto near the singular vector corresponding to its maximum singular value of the output controllability matrix of the robotic arm. Therefore, if we can control the direction of the singular vector by applying the dynamics shaping, we will be able to control the direction of the positional error of the end-effector caused by the disturbance. We propose a novel motion planning based on the dynamics shaping and verify numerically and experimentally that the robotic arm can robustly hit the target toward the desired direction with a simple open-loop control system even though the disturbance is applied.

Grasp planning based on dynamics shaping

“…It is found that the manipulation task accuracy depends on the grasp configuration such as the contact position, the hand configuration and the object's position and orientation. We propose a novel grasp planning which finds the grasp configuration with high manipulation task accuracy, which is called "dynamics shaping" [12]. As a simulation example, Fig.…”

“…The dynamics shaping has been applied to plan the robot arm's global motion such as the hitting motion [12] and the tracking motion [13].…”

Planning tracking motion insusceptible to unknown disturbances using sensitivity measure

“…Changing arm postures to obtain arm's dynamics and kinematics which are insusceptible to unknown disturbances is called dynamics shaping [10]. We consider that errors perpendicular to the direction of a desired end-effector's motion are more important in tracking tasks such as welding and painting since such errors cause collision with a workpiece.…”

“…However, these methods have not designed to find arm motions which are insusceptible to unknown disturbances. In this paper, based on our previous work on robust hitting by the robotic arm [10], [11], which finds the arm trajectory insusceptible to unknown disturbances for hitting a stationary object, a novel tracking motion planning method is proposed. This paper is organized as follows.…”