High Speed Motor Control

Overview

The project suggested was to design a system for high speed motor control using the PIC 32. To demonstrate the motor control, a two degree of freedom (2DOF) robot arm was designed to throw and catch one ball with itself.

Team Members

• Sam Bobb (Electrical Engineering senior)
• Daniel Cornew (Mechanical Engineering junior)
• Ryan Deeter (Mechanical Engineering junior)

Mechanical Design

Theory of Parallelogram Design

Equations of Motion

Commanding the arm is much easier for a user to do in x- and y- coordinates than in motor angles or encoder counts. Therefore, equations were required that would translate x- and y- coordinates into angles from horizontal and then into encoder counts. Equations to express the reverse (encoder counts to angles to x- and y- coordinates) were also needed to evaluate the accuracy of the execution with respect to the command path.

• $x=L\cos ({\theta }_1)\backslash +\cos ({\theta }_1+{\theta }_2)$
• $y=L\sin ({\theta }_1)\backslash +\sin ({\theta }_1+{\theta }_2)$
• ${\theta }_1=\frac{-(2L\sin ({\theta }_2))x+(L+2L\cos ({\theta }_2))y}{(2L\sin ({\theta }_2))y+(L+2L\cos ({\theta }_2))x}$
• ${\theta }_2=co{s}^{-1}\left(\frac{x^2+y^2-L^2-(2L{)}^2}{2L^2}\right)$

Note: In the code, ${\theta }_2$ is written out explicitly in the equation for ${\theta }_1$, but was defined as above for ease of reading.

Results

It was awesome.