A semi-autonomous adaptive impedance grip force controller for teleoperated object grasping

Abstract

While defusing a bomb or performing a rescue mission with a teleoperated robot, grasping various objects is crucial. Despite being a routine activity, remote grasping is still challenging. It is difficult to apply an adequate grip force to avoid slippage and damage to an object. An additional challenge is controlling both motion and force at the same time during remote robot control (teleoperation). Therefore, this research presents a teleoperated semi-autonomous controller which assists the user with remote grasping by relieving the user from controlling the grip force. Our design enables the user (1) to control the position of the remote gripper while (2) the system controls the grip force autonomously. When the user grasps an object, the semi-autonomous controller maintains the grip force based on tactile feedback to prevent object slippage. For tactile feedback, our system uses a tactile sensor that can detect incipient slippage from deformations at the location of the contact. With two experiments, we show that the system can maintain an adequate grip force while being robust to external perturbations and input changes. Since this controller stably grasps objects while the user maintains control over the position of the remote robot, our method relieves the user and prevents object slippage