Adaptive Soft Robotic Gripper Based on Shape Morphing Compliant System

Abstract

This paper presents a new shape morphing compliant system - a shape morphing compliant structure with integrated actuators and sensors - for application as an adaptive soft robotic gripper. In many of today industries, there is a need to grasp differently shaped and sized objects as well as objects of a different stiffness or very soft objects. Classical rigid-body based grippers cannot safely manipulate such a wide variety of objects, as they are stiff and not adaptive. By integrating actuators within a compliant structure or mechanism, it is possible to develop an adaptive soft gripper that can achieve multiple shapes of its grasping surface i.e. different grasping patterns. Such gripper would be able to adapt its shape to different shaped objects and to realize safe grasping. By additionally integrating sensors, a compliant system results and the gripper can detect contact with objects. Via developed controller and actuators, appropriate shape morphing of its grasping surface can be realised. The concept of a two-finger gripper and a functional model of one gripper finger are presented in the paper. Actuators are formed by using shape memory alloy wire nitinol and sensors are formed by using conductive graphite foam. It will be shown that developed compliant system can realize an adaptive soft gripper finger with different grasping shapes. The control algorithm for the gripper finger is developed as well and it will be demonstrated that the gripper finger can decide which actuator needs to be activated in order to achieve appropriate shape morphing. The presented adaptive soft gripper structure can have many potential applications in robotics.