Optimization and Experimental Study of Bionic Compliant End-effector for Robotic Cherry Tomato Harvesting

High harvesting success rate is part of the key technologies for robotic cherry tomato harvesting, which is closely related to the structural design of the end-effector. To obtain a high success rate of fruit harvesting, this paper presents a compliant end-effector with bio-inspired tarsus compliant gripper inspired by the structure and mechanics of the tarsal chain in the Serica orientalis Motschulsky. Response Surface Methodology (RSM) based on Box Behnken Design (BBD) technique has been used to optimize the key structural parameters of the bionic compliant end-effector for achieving the expected results in pulling pattern for robotic cherry tomato harvesting. Experiments were designed by maintaining three levels of four process parameters—Length of the Offset Segment Tarsomere (OSTL), Angle of the Inclined Segment Tarsomere (ISTA), Thickness of the Extended Segment Tarsomere (ESTT) and Length of the Extended Segment Tarsomere (ESTL). According to the optimization analysis results, the best parameter combination is OSTL 23 mm, ISTA 14°, ESTT 5.0 mm, ESTL 23 mm. Besides, the harvesting performance of the optimized bionic compliant end-effector was verified by experiments. The results indicated the harvesting success rate of fruits with different equatorial diameters was not less than 76%.