A Force-Controlled Gripper Capable of Measuring Mechanical Properties of an Object

Various sensorized grippers have been developed to handle delicate objects safely. 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 paper proposes a force-controlled 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, accurate position and force sensing can be achieved at any location of each finger. When gripping an object, the size and stiffness of the object can thus be accurately measured. Simulation and experimental results demonstrate the proposed gripper’s merits. We expect this new gripper to provide a more competitive solution for robots that need to manipulate objects and check their mechanical qualities at the same time.