Parameters for the Cart and Motor

The response of the cart and motor system to square wave inputs of frequencies 0.1 Hz to 15 Hz was recorded on the chart recorder and plotted on a Bode plot. The primary breakpoint between the line of slope -20 Db/decade and the line of -40 Db/decade occurred at 1 Hz (or omega = 6.28 rad.) A secondary breakpoint of unknown origin occurred at 7 Hz.

The cart gain constant ksubp was obtained by analyzing the magnitude of the cart oscillations for low frequencies. Using the equation


the value of ksubc was determined by assuming the cart acceleration xdot2p was zero for low frequencies and then calculating the average velocity xdot1p from the chart recorder.