Technology of grasp fruit and vegetable based on external force control loops

The open architecture force control system of manipulator grasping was designed based on PC.Grasp force gradually turned small because of the deformation of fruit and vegetable in the process of manipulator grasping.It was necessary to consider the effect of deformation on grasp force,so the external force control loops algorithm was proposed for the control system in experiment.It converted the force error into the speed input command of position control system.The manipulator speed was adaptively decelerated when the grasping force increased in order to reduce force overshoot.Proportional and incremental proportional integral algorithm were adapted to force controller in experiment,both algorithms proved that speed of manipulator would automatically decelerate when grasping force increased.The results showed that it was a good control algorithm by automatic variable speed of manipulator grasping based on external force control loops,which could reduce grasp force overshoot and decrease the damage of fruit and vegetable caused by agricultural robot grasping.