RC motor control

The final goal of this project is to build a cheap series elastic actuator (SEA) similar in function to those seen on modern robots such as: http://yobotics.com/actuators/actuators.htm.

I’m from a mechanical background, so I expected the electronics to be a huge obstacle. luckily i discovered the arduino, and have been happy ever since.

this is still a work in progress, but currently i have a my PC connected to my arduino through USB, then my arduino is connected to an Electronic Speed Control (ESC) that i bought off NitroRCX.com. The ESC is powered by a 12V 45AH car battery and connects to a sensorless AC motor that can draw up to 28A (roughly 336W depending on the voltage supplied by the battery).

From the terminal on my PC i specify a value between 0 and 9, 0 being full forward and 9 being full reverse. The arduino then translates this into the correct value:
(input-48)*6+60
and feeds this into the Servo library which i believe i also modified for higher performance:

#define MIN_PULSE_WIDTH       544     // the shortest pulse sent to a servo  
#define MAX_PULSE_WIDTH      2400     // the longest pulse sent to a servo 
#define DEFAULT_PULSE_WIDTH  1500     // default pulse width when servo is attached
#define REFRESH_INTERVAL      100     // minumim time to refresh servos in microseconds

but it’s been a while, so I could be wrong. Anyways, I have a spindel axel to which I’ve mounted my motor using a mount i rapid prototyped. The whole thing looks pretty slick atm, but is far from finished. Just thought I’d show off my progress so far. Check the attachments for the pictures and the code i used.

The action:

ESC - eZRun-35A-RC ESC for Rock Crawler
Motor - Alpha 480 (1020kv)

RunSpeedControlThroughConsole.pde (897 Bytes)

This is still a work in progress, but I have my computer via a USB connection to my Arduino, and then my Arduino is connected to an electronic speed control system (ESC), I bought NitroRCX.com's. ESC is 12V45AH car battery and AC motor connected to the sensor, can draw 28A (depending on the voltage supplied by a battery of about 336W).