A Sensorized Hybrid Gripper to Evaluate a Grasping Quality Based on a Largest Minimum Wrench

Soft pneumatic grippers, which are based on soft pneumatic actuators have been widely studied owing to their simple morphological structure, inherent compliance, and pliable grasp. Additionally, the integration of the soft gripper with various sensors to improve its functionality has also been extensively studied. Although the soft gripper is known to exhibit a robust grasping performance without accurate control, the grasping quality of the soft gripper has rarely been studied due to the lack of adequate embedded sensors and quality metrics of the soft gripper. Therefore, a hybrid gripper, which is a soft gripper with rigid components, was sensorized by embedding a soft force sensor and a bending sensor to evaluate the grasping quality. Furthermore, a new grasping quality metric for a soft gripper was proposed, which calculates the largest minimum wrench of a convex hull in the wrench space. The proposed grasping quality metric was experimentally verified, and a real-time program was developed to evaluate the grasping quality.