A Force-Sensing Compliant Gripper Based on Drivetrain Elasticity

Various sensorized grippers have been developed to safely handle delicate objects and avoid environmental collision. Sensors mounted on the gripper fingers’ surface can provide direct force measurements. However, multiple sensors are often required on one finger, which leads to significant complexity in sensor placement and wire routing. Finger-based sensors are limited to the sensing of external gripping force. In addition, the fingers cannot be easily replaced to meet the requirement of objects with specific geometries. To avoid the complexity and limitation of finger surface sensors, this paper proposes a compliant two-fingered gripper that relies on the deformation sensing of elastic elements in the drivetrain to obtain the finger force. By using a minimum number of optical encoders placed in the drivetrain, multi-dimensional and independent force sensing can be achieved at any location of each finger. The electronic complexity of the fingers can also be minimized. Simulation results are provided to demonstrate the merits of the proposed compliant gripper. We expect that this new compliant gripper can provide a more competitive solution for robots to manipulate objects in force-sensitive environments.