Dynamic Conveyor Tracking Control of a Delta Robot

Abstract

For general dynamic pick and place tasks that the objects are transferred with high speed by the conveyor belt, the capability of a delta robot to track the traveling objects is very important for the efficiency. To meet the needs of precision and smooth control, a computed-torque control scheme for conveyor tracking is implemented in this paper. For higher efficiency and accuracy, computer vision system, encoder and conveyor belt region are incorporated into the control scheme. Dividing the conveyor belt into three regions, the robot is commanded to track, pick and give up according to the subregions. Conveyor belt is equipped with an encoder that provides the controller with real-time position and speed of the belt. Based upon those informations, the controller automatically compensates the end positions with respect to the belt to adjust for the position of the conveyor. Then, the conveyor tracking problem is converted to a subregional tracking problem.

Experimental and simulation studies of motion control of a Delta robot using a model-based approach

“…where m P , m 1 , and m 2 , respectively, refer to the masses of the end effector, the links A i B i , and the links B i D i . Since equations (8) and (9) are the functions of six variables X P , Y P , Z P , and 1i , the Lagrangian should incorporate with three constraint equations as equation 2, which leads to the dynamic equations as…”

“…Zhang et al investigated the conveyor tracking of a Delta robot, and the controller design is based on a computer vision system and encoder signals so as to compute the joint torques. 9 Rachedi et al applied the H 1 controller to a Delta robot, where the controller is multi-input multi-output centralized feedforward control based on the computed joint torques. 10 Generally speaking, there are two types of control schemes for robot manipulators, position-and modelbased control.…”