DESIGN AND EXPERIMENT OF A SAFFLOWER PICKING ROBOT BASED ON A PARALLEL MANIPULATOR

ABSTRACT

To mitigate the large demand for safflower picking labour and the low efficiency of manual picking, a safflower picking robot that is based on a parallel manipulator is designed. The whole robot mainly consists of a walking device, parallel manipulator device, vision device, picking device, filament collection device, control system, and motor drive system. The forward and inverse kinematics analysis of the parallel manipulator is analysed via a geometric method, the kinematics model is established, and the computational analysis of the parallel manipulator working speed is based on the Jacobi matrix. For driving angle errors of 0.001∼0.005°, the moving platform's motion accuracy is 0.2174–0.9387 mm, which meets the position accuracy requirements of the test stage. Based on MATLAB software, the Monte Carlo method is employed to solve the working space of the parallel manipulator, which is approximately an equilateral triangle with a side length of 0.35 m, which satisfies the safflower growth space picking conditions. The prototype is constructed, and safflower picking experiments are carried out under laboratory conditions. The average picking period of each flower bulb was 16 s, and the average net picking rate of the filaments was 87.91%. The experimental results verified the applicability of the safflower picking robot.

KEYWORDS
Picking robot; Parallel manipulator; Safflower; Kinematics analysis; Net picking rate