Numerical Simulation of Horizontal Articulated Robots in Consideration of Flexibility of Mechanical Systems
Hiroyuki Kojima*, Hiroshi Takahashi** and Hideharu Kuwana**
*Faculty of Engineering, Gunma University, 1-5-1, Tenjin, Kiryu-shi, Gunma 376, Japan
**Oki Electric Industry Co., Ltd., 1-7-12, Toranomon, Minato-ku, Tokyo 105, Japan
In this report, the numerical simulation of a horizontal articulated robot consisting of two horizontal rotating links and a vertical linear link is presented. In the numerical simulation, the pendulum vibrations of the vertical linear link, in the plane perpendicular to the second horizontal rotating link, are considered. Then, in the derivation of the state equation of the robot, the equation of motion of the mechanical system is derived in consideration of the flexibility and viscosity of the coupling mechanism between the second horizontal rotating link and the vertical linear link as well as the nonlinear flexibility of the harmonic drives, and the nonlinear state equation of the robot is obtained by coupling the equation of motion with the electric current equation of the servo position control system based on the proportional plus integral plus derivative control. Furthermore, the numerical simulation results are demonstrated, and the effects of the pendulum vibration of the vertical linear link on the dynamic characteristics of the robot and the control accuracy are investigated.