Session: 07-04-01 Design and Control of Robots, Mechanisms and Structures I

Paper Number: 73288

Start Time: Monday, 12:25 PM

73288 - Design and Modelling of SCARA Robot Variant 

The SCARA robot has been extensively used for industrial applications for many years. The motivation behind this research is to propose a SCARA variant as an alternative, with the popularity and applications of a SCARA robot. The main objective is to relocate the vertical prismatic joint and study the computational dynamics of the SCARA variant and the performances. The vertical prismatic joint in this modified SCARA variant is changed to axis 2 from axis 3 in the original configuration. The SCARA variant has been analyzed for the forward and inverse kinematics based on the transformation matrix method.

The dynamic model for the SCARA variant has been developed by using the Lagrangian method, and the systematic steps presented in this work can be easily applied for other robotic systems. The SCARA variant is a new design for the robot and has been developed for any change in the applications or workspace of the standard SCARA robot. The results for the equations have been compared to the standard SCARA, it has been found that the results are identical apart from the mass inertia and Coriolis matrices having terms in columns 2 & 3 exchanged.

In this paper, linear and nonlinear trajectories, such as straight line, ellipse, and circular trajectories have been selected  in the simulation study. Consistent results for torque requirements have been observed with the linear trajectory having the least values, followed by ellipse, and the circular trajectory having the highest values. For all the trajectories, the prismatic joint at axis 2 has the highest torque required and the revolute joint at axis 4 has the least. The values of the required forces on the robot are consistent and within the limits of industrial applications. Once the equations of motion have been derived, there is a need to determine the power required by the joints to drive the end effector along desired trajectories. Nonlinear and linear trajectories have been selected and the joint level torques are analysed for a duration of 2 seconds for fast industrial applications. Simulations for required forces show acceptable results. The computational dynamics can be used as a guide tool for the selection of the actuators in the real implementation.

 

This design can be chosen as an alternative for the standard SCARA when the requirement arises. It would be interesting to use the proposed SCARA configuration to study the control torques required for trajectories and the tracking errors along the paths, which can be a future work. Further scope of the research can also be done by adding mass to the simulations.

Presenting Author: Puren Ouyang Ryerson University

Authors:

Manjeet Tummalapalli Ryerson University
Puren Ouyang Ryerson University
Johnny Bahri Ryerson University