Abstract In modern manufacturing industry, the application of automation and intelligent technology has become an important driving force to improve productivity and product quality. In this paper, an underactuated picking manipulator end effector design based on a single shape memory alloy (SMA) spring is proposed to solve the problems of labor shortage and inefficiency in the picking process of economic forest fruits (e.g., plums and peaches). By analyzing the theoretical, simulation and experimental results, the SMA spring under driven picking end effector designed in this paper can achieve non-destructive picking of plums or other perishable fruits with diameters ranging from 20 mm to 70 mm. Compared to the conventional picking end effector, the SMA spring underactuated picking end effector proposed in this study uses only one SMS spring instead of a motorized drive system, which simplifies the mechanical structure. The feedback closed-loop control of the gripping force is constituted in the control system of the end effector, which precisely controls the contraction force of the SMA spring to ensure the stability and reliability of the gripping process. This study provides a reference technical solution for automated and intelligent harvesting in agroforestry and a new idea for flexible gripping in intelligent manufacturing.
Zhao et al. (Thu,) studied this question.