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.

$x=L\cos(\theta _{1})\ +\cos(\theta _{1}+\alpha )$

$y=L\sin(\theta _{1})\ +\sin(\theta _{1}+\alpha )$

$\alpha =cos^{-1}\left({\frac {x^{2}+y^{2}-L^{2}-(2L)^{2}}{2L^{2}}}\right)$

$\theta _{1}={\frac {-(2L\sin(\alpha ))x+(L+2L\cos(\alpha ))y}{(2L\sin(\alpha ))y+(L+2L\cos(\alpha ))x}}$

$\theta _{2}=\theta _{1}+\alpha \,$

Note: $\alpha \,$ is used to calculate $\theta _{1,2}\,$ in the MATLAB code and is not ever sent to the PIC.

Results

It was awesome.