Workspace design of robots<br /> -Nishant Iyer<br />
What is a robot?<br />A robot is a mechanical intelligent agent which can perform tasks on its own, or with guidance.<br />It is usually an electro-mechanical machine which is guided by computer and electronic programming.<br />
What is degree of freedom?<br />It is the total number of independent motions that can be performed by a rigid body.<br />Lets understand this in a little more detail.<br />
Lets understand DOF<br />Any free body in 3D space can perform translation and rotation along x , y and z axes.<br />Just imagine a brick floating without gravity.<br />This accounts to a total of 6 DOF.<br />
What does DOF depend on?<br />A maximum of 6 DOF is possible for any rigid body.<br />Now the degree of freedom depends on the kind of joint and constraints on a robot.<br />Different joints give different DOFs.<br />Lets see some examples.<br />
Types of joints and their DOFs<br />A pin joint gives a single degree of freedom as it permits rotation only along the pin axis.<br />A ball and socket joint gives 3 DOFs as it allows rotational motion along the three axes. Translation motion is restricted in this.<br />
Understanding workspace<br />To understand workspace , lets consider a cylindrical configuration robot.<br />This has the capability to perform linear motion along z and y axes.<br />It also rotates along the z-axis.<br />This its DOF will be 3.<br />
Understanding workspace<br />This is how its workspace/work volume be like.<br />Lets work out step by step how this came about. <br /> Workspace of acylindrical configuration robot<br />
Step by step formation of a workspace/work volume<br />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.<br />
Similarly keeping the y co-ordinate minimum, we trace the smaller inner curve.<br />This is the workspace of the robot along just 2 DOF. i.e. rotation along z-axis and translation along y-axis.<br />
Finally the workspace is obtained<br />Now this robot can perform translation motion along z-axis.<br />Hence we extrude the one dimensional figure along the z-axis till the maximum value is reached.<br />This gives us the three dimensional workspace of the robot. <br />
Why is knowledge about work volume important?<br />The work volume defines the total volume swept by the end effector of a robot.<br />In industrial assembly lines there will be many robots and components nearby to each other.<br />Its upto us to programme the motions of the links of the robot such that there are no collisions.<br />
How can it be controlled or designed?<br />The work volume can be designed as per requirements.<br />This is possible by controlling the movements of links by setting maximum values to the actuators at the joints.<br />The maximum values have to be set according to the obstructions around the robot.<br />
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.