Research Of The SCARA Robot Actuated By All-fixed Motors

With the development of industrial automation, the application fields of the industrial robot have been expanded widely. To meet the requirement of a small transfer robot with the price under twenty thousand yuan in RMB for some small and medium enterprises, this paper proposes a SCARA robot actuated by all-fixed motors, which is different from traditional SCARA robots. In this novel SCARA robot, all the driving motors are installed in the base, and sleeves and synchronous belts are used to transmit motion and force. The end-effector can achieve catch and release motions with the cylinder and chuck. Therefore, the robot has a cheap price and a relatively good reliability, which can be applied to transport work with normal precise.This dissertation presents a theoretical analysis and a structural design for a SCARA robot actuated by all-fixed motors. The major merits can be summarized as follows:The CAD model of the novel SCARA robot is established. The homogeneous transform matrix and algebraic method are employed for the forward and inverse kinematics of the robot. To verify the validity of the inverse kinematics, the SolidWorks Motion software is used for simulation, which lays the foundation of the development of control system.The dynamics equations of the SCARA robot are derived by the Lagrange method, and the torques of the actuation joints are obtained. Similarly, the simulation is based on the SolidWorks Motion software, and the results can support the future researches of the selection of motor and joint material and design of sleeves.The statics of different components of the SCARA robot is conducted by the ANSYS Workbench software. The results shows the design parameters meet the requirements of intensity and stiffness. In addition, modal analysis for the small arm shows the inherent frequency of the small arm is greater than the resonant frequency, which satisfies the design demands.The structural design of the SCARA robot actuated by all-fixed motors are based on above analysis. Then the transmission scheme is determined and some major standard components including stepping motor, synchronous belt, cylinder and chuck are selected. Moreover, the structure and layout of the sleeves installed in the arms are detailed designed. Finally, prototype of the robot is completed, which can be used in practical work.The experiments for the prototype of the SCARA robot is performed. First, the prototype of the robot is set up. Then, a series of major indices of technical parameters are detected, and the result meet the expected design requirements. Finally, the experiment of handling operation for real application is conducted.This paper makes contributions to the application and popularization of small transfer robots with plane motion.