Let's Make Robots!

cr0c0's blog

cr4cX Motor Controller

This blog is about the cr4's motor controller - updated 2012.03.22

Controller features:

  • controls two H bridges;
  • reads, interrupt based, two quadrature encoders;
  • implements PID algorithm for controlling the speed of the motors;
  • synchronize the motors;
  • communicates through Serial and I2C/TWI;
  • monitors the supply voltage;
  • monitors the current through the motors.

cr4cX H-Bridge

The cr4's H-Bridge is builded with MOSFET and BJT transistors and specialized low-side driver IC.

In my tests the bridge has worked at 32KHz PWM frequency with virtually no heat generated.

Two of these (one for each motor) are used in cr4.

The bridge prevents the shoot through conditions and allow the following operating modes:

  • pwm cw rotation
  • pwm ccw rotation
  • pwm brake
  • brake
  • coast

Maximum supply voltage is around 18V and maximum current through the motors is limited by the IRF9540 MOSFET caracteristics.

cr4cx - Security robot/Telepresence

cr4cx should be an autonomous home security bot.
It must also work as a telepresence/mobile camera and mobile media player.

cr2cX - The long story

cr2cX was born as a robotic platform to test and experiment various concepts of the robotics field.

Because I have designed and build a robot 16 years ago I considered that it will be useful to start again and teach my kid some things. I have taken the hard way by designing and building every module and piece of software. To be able to speed the building and experiments a little, I've taken some shortcuts: