On the dynamics of SCARA robot

Padhy, S.K., On the dynamics of SCARA robot, Robotics and Autonomous Systems, 10 (1992) 71-78. Assembly automation using robots has proven to be very successful. It has been shown that use of robots improves the accuracy of assembly, and saves assembly time and cost as well. SCARA (Selective Compliance Assembly Robot Arm) type robots have been widely used in industry for assembly operations in both the mechanical and electronics domains of manufacturing. One of the important issues in designing an optimal manipulator is the dynamic behavior of the manipulator which is highly non-linear and strongly coupled due to the interaction of inertial, centripetal, coriolis and gravitational forces. Although extensive study involving optimal time study, dynamic study using the Lagrange method, path planning etc. have been made, no closed solution for the dynamics of this important robot has been reported. This paper presents the study of kinematics and dynamics of the SCARA assembly robot. Closed solutions for the dynamics of this robot are derived. To study the variations of the torques of the links a computer code is developed. It is found that the torque is independent of the angular position, which makes the robot highly compliant.