Optimization of Grasping Efficiency of a Robot Used for Sorting Construction and Demolition Waste

The recycling of construction and demolition waste (CDW) remains an urgent problem to be solved. In the industry, raw CDW needs to be manually sorted. To achieve high efficiency and avoid the risks of manual sorting, a sorting robot can be designed to grasp and sort CDW on a conveyor belt. But dynamic grasping on the conveyor belt is a challenge. We collected location information with a three-dimensional camera and then evaluated the method of dynamic robotic grasping. This paper discusses the grasping strategy of rough processed CDW on the conveyor belt, and implements the function of grasping and sorting on the recycling line. Furthermore, two new mathematical models for a robotic locating system are established, the accuracy of the model is tested with Matlab, and the selected model is applied to actual working conditions to verify the sorting accuracy. Finally, the robot kinematics parameters are optimized to improve the sorting efficiency through experiments in a real system, and it was concluded that when the conveyor speed was kept at around 0.25 m/s, better sorting results could be achieved. Increasing the speed and shortening the acceleration/deceleration time would reach the maximum efficiency when the load would allow it. Currently, the sorting efficiency reached approximately 2 000 pieces per hour, showing a high accuracy.