A Compliant Gripper with Two-Dimensional Force Sensing on Each Finger

Various sensorized grippers have been developed to handle delicate objects safely and avoid environmental collisions. These grippers have sensors mounted on their fingers' surface that provide direct force measurements. However, multiple sensors are often required on one finger, leading to significant sensor placement and wire routing complexity. Finger-based sensors are limited to sensing external gripping force, and fingers cannot be easily replaced to meet the requirements of objects with specific geometries. To overcome the complexity and limitations of finger surface sensors, this article proposes a compliant two-fingered gripper that relies on the deformation sensing of elastic elements in the drivetrain to obtain finger force. By using a minimum number of optical encoders placed in the drivetrain, multidimensional and independent force sensing can be achieved at any location of each finger. The electronic complexity of the fingers can also be minimized. Experimental verifications and gripping examples demonstrate the proposed compliant gripper's merits. We expect this new compliant gripper to provide a more competitive solution for robots to manipulate objects in force-sensitive environments.