detailed description about formation of robot workspace

1. Workspace design of robots -Nishant Iyer

2. What is a robot? A robot is a mechanical intelligent agent which can perform tasks on its own, or with guidance. It is usually an electro-mechanical machine which is guided by computer and electronic programming.

3. Some examples to understand them more

4. What is degree of freedom? It is the total number of independent motions that can be performed by a rigid body. Lets understand this in a little more detail.

5. Lets understand DOF Any free body in 3D space can perform translation and rotation along x , y and z axes. Just imagine a brick floating without gravity. This accounts to a total of 6 DOF.

6. What does DOF depend on? A maximum of 6 DOF is possible for any rigid body. Now the degree of freedom depends on the kind of joint and constraints on a robot. Different joints give different DOFs. Lets see some examples.

7. Types of joints and their DOFs A pin joint gives a single degree of freedom as it permits rotation only along the pin axis. A ball and socket joint gives 3 DOFs as it allows rotational motion along the three axes. Translation motion is restricted in this.

8. Understanding workspace To understand workspace , lets consider a cylindrical configuration robot. This has the capability to perform linear motion along z and y axes. It also rotates along the z-axis. This its DOF will be 3.

9. Understanding workspace This is how its workspace/work volume be like. Lets work out step by step how this came about. Workspace of acylindrical configuration robot

10. Step by step formation of a workspace/work volume Keeping y co-ordinate at its maximum value, and tracing the path of a point on end effector by rotating only along z-axis, we get the shown curve.

11. Similarly keeping the y co-ordinate minimum, we trace the smaller inner curve. This is the workspace of the robot along just 2 DOF. i.e. rotation along z-axis and translation along y-axis.

12. Finally the workspace is obtained Now this robot can perform translation motion along z-axis. Hence we extrude the one dimensional figure along the z-axis till the maximum value is reached. This gives us the three dimensional workspace of the robot.

13. Why is knowledge about work volume important? The work volume defines the total volume swept by the end effector of a robot. In industrial assembly lines there will be many robots and components nearby to each other. Its upto us to programme the motions of the links of the robot such that there are no collisions.

14. How can it be controlled or designed? The work volume can be designed as per requirements. This is possible by controlling the movements of links by setting maximum values to the actuators at the joints. The maximum values have to be set according to the obstructions around the robot.