Design and experiment of fruit and vegetable grasping system based on grey prediction control

Incremental PI (proportional integral) force control algorithm was proposed based on grey prediction for making grasp force track set value quickly with small overshoot between end-effector and deformable fruit and vegetable. Grey prediction model was built by the signal of grasp force acquired from the sensor, the weights of predictive force error were increased or decreased in integrated error accordingly to the precision of predictive model. Force controller could employ the past, present and future grasp force information to calculate an appropriate control correction to pre-compensate the force error, and could yield small overshot, fast response simultaneously, so make the controller adaptive to the dynamic grasp process between fruit and end-effector. Experimental results demonstrated the efficacy of grey predictive incremental PI algorithm, which the damage of grasping fruit and vegetable could be decreased.