Measurement of shear forces during gripping tasks with a low-cost tactile sensing system

Abstract

To grasp and manipulate complex objects, robots require information about the interaction between the end effector and the object. This work describes the integration of a low-cost 3-axis tactile sensing system into two different robotic systems and the measurement of these complex interactions. The sensor itself is a small, lightweight, and compliant silicone based capacitive sensor. The soft and conformable design of the sensor allows it to be integrated within a variety of end effectors and locations on those end effectors (e.g. wrapped around a finger). To improve integration and data collection of the sensors, a custom interface board and ROS (Robot Operating System) package were developed. Sensor data has been collected from four different tasks: 1. pick and place of non-conductive and conductive objects, 2. wrist-based manipulation, 3. peeling tape, and 4. human interaction with a grasped object. In the last task, a closed loop controller is used to adjust the grip force on the grasped object while the human interacts with it.