Design and simulation experiment of ridge planting strawberry picking manipulator

Strawberry picking robot arm is an important part of strawberry picking operation. The narrow and complex working environment of ridged strawberry is a great challenge for strawberry picking. Aiming at the problems of narrow working space and complex working environment for strawberry picking in ridge farming, a P-R-R-P-R-R strawberry picking arm is proposed to realize automatic picking of strawberries in ridge farming. By establishing the kinematics model of the strawberry picking manipulator, the Jacobian condition number and operability index of the strawberry picking manipulator are solved to analyze the dexterity of the manipulator. In order to analyze the performance of each joint of the strawberry picking manipulator in the picking operation, a dynamic model of the strawberry picking manipulator was established. The strawberry picking arm has no singular position within the set strawberry picking point range, and the operability indexes are all greater than 0.38. According to the growing environment of strawberry, the simulation route of strawberry picking and the picking operation cycle were set and tested by experiments. Compared with the S-curve motion mode, the motion of each joint of the strawberry picking robotic arm is less smooth in the uniform acceleration-uniform speed-uniform deceleration motion mode. However, the peak velocity of each joint in the uniform acceleration-uniform velocity-uniform deceleration motion mode is lower than that in the S-curve motion mode, Taking three-joint as an example, the peak velocity of S-curve is 19.8° per second, higher than that of the uniform acceleration-uniform speed-uniform deceleration motion mode, which is 16.6° per second. Since joint 4 needs to overcome the influence of gravity, its peak force exceeds 15.5 N. It did not reach the farthest point of its own stroke during the picking process, resulting in a low moment of inertia at the three joints to the end which caused the peak moment of joint 3 to range from 0.2 N·M to 0.31 N·M. The peak torque of joint 5 is all under 0.1 N·M. The total power consumption of the strawberry picking robotic arm is 0.1622 J in a single picking operation using the uniform acceleration-uniform speed-uniform deceleration motion mode. In conclusion, the strawberry picking manipulator designed in this study has good dexterity and can adapt to a ridge environment.