Abstract:In order to use the same end-effector to grasp fruits and vegetables which have various shapes and effectively avoid the end-effector damaging fruits and vegetables under the premise of ensuring capture efficiency, a kind of multifunctional dragonfly claws form biomimetic end effector was designed. Firstly, the relevant physical information of each claw finger of dragonfly was transformed into a data and quantitative model by using a stereomicroscope, and the size of the end of femur was determined through theoretical analyzing, actuating design, modeling and optimization of structure parameters, the length of mechanical front claw’s femur, tibia and the tarsus were 36mm, 48mm and 31mm, respectively, and mechanical median claw’s femur, tibia and tarsus length were 48mm, 48mm and 36mm, respectively. Meanwhile, D-H method was adopted to establish the motion model of the end-effector, and draw the envelope space region of end-effector. The results turned out that the manipulator can fully envelop the main parts of various fruits and vegetables. Finally, the static load test which was on the platform of parallel-mechanism and serial-mechanism was carried out to determine the ultimate stress, and the fruit as well as vegetable grabbing test was also carried out. The average capturing success rates of mechanical hand on the tomato, apple, pepper and eggplant were 90.7%, 88.6%, 87.9% and 87.2%, respectively, and the average damage rates were 4.3%, 0.7%, 3.6% and 2.1%, respectively. The test results showed that the end effector realized the effect of using the same mechanical hand to grab many kinds of fruits and vegetables stably and smoothly.
