Optimal Design Of Redundant Drive Cartesian Robot Based On Flexible Mechanism

In order to achieve high-speed and high-precision motion for X-Y-Z Cartesian robot. In the X direction and Y direction of the mechanical structure design,Rectangular coordinate robot without using traditional ball screw and synchronous belt transmission mechanism. The direction of the robot in the direction of X is directly driven by a linear motor.. Rectangular coordinate robot also adopted a direct-drive in Y direction. Since the Y direction beam has two end effector reciprocating motion, a shaft type linear motor with two mover is designed to realize direct drivei in the Y direction.The control system of the Cartesian robot is based on the touch screen as the upper computer., the next bit machine is PLC. X direction and Y direction of the movement is done with grating ruler and grating encoder as the position feedback to form a closed loop control.The speed and accuracy of the robot are improved by the direct drive. But the rectangular coordinate robot in the X direction is not just one side of the motor drive with linear motor, but also a symmetrical design of the redundant drive was used too. However, the redundant drive will cause difficulties on the motion control and affect the smooth motion of the system.In order to eliminate the problems caused by redundant drive, in this paper, starting from the principles of mechanism, the topological analysis of linkage mechanism is also carried out. Linkage was used to make the rigid structure of a redundant drive into a five-bar mechanism which have two degrees of freedom and have a certainty motion of non-redundant. The non-drive joint of the five-bar mechanism is designed for flexible joints. When the flexible joints replace the rigid joints, in order to satisfy the design requirement, a dimensionless objective function is established. Orthogonal optimization algorithm showed the optimal design size of the flexible joint. Finite element simulation results show that flexible joint not only eliminates the redundant drive,but also enhance the performance of the robot’s movement. The results of the modal analysis show that the robot is well avoided the resonance.