Search Here MISC  Parts List  Robot Forum  Chat  Member Pages  Axon MCU  Robot Books  Shop  Contact HARDWARE  Actuators  Batteries  Electronics  Materials  Microcontrollers  Sensors SCIENCE  Robot Journals  Robot Theory  Conferences PROGRAMMING - DIFFERENTIAL DRIVE What is a Differential Drive Robot? Differential drive is a method of controlling a robot with only two motorized wheels. What makes this algorithm important for a robot builder is that it is also the simplest control method for a robot. The term 'differential' means that robot turning speed is determined by the speed difference between both wheels, each on either side of your robot. For example: keep the left wheel still, and rotate the right wheel forward, and the robot will turn left. If you are clever with it, or use PID control, you can get interesting curved paths just by varying the speeds of both wheels over time. Dont want to turn? As long as both wheels go at the same speed, the robot does not turn - only going forward or reverse. The differential drive algorithm is useful for light chasing robots. This locomotion is the most basic of all types, and is highly recommended for beginners. Mechanical construction, as well as the control algorithm, cannot get any simpler than this. Note that this algorithm doesnt just work for wheeled robots, but is also the same algorithm you must use for tank tread type robots and biped robots. For examples of differential drive robots, see my sumo robot, mobipulator robot, and robot boat. How to Use This Algorithm Place two motorized wheels on your robot, one on either side. Send your move commands to the motors by either using a motordriver or H-bridge. Or if you are using servos, just send the required pulse width. Note that this algorithm works great with the photovore algorithm. pseudocode: input sensor reading make decision based on sensor reading do one of below actions: to drive straight both wheels move forward at same speed to drive reverse both wheels move back at same speed to turn left the left wheel moves in reverse and the right wheel moves forward to turn right the right wheel moves in reverse and the left wheel moves forward Two robot soccer teams of custom differential drive robots: Get Your Ad Here Has this site helped you with your robot? Give us credit - link back, and help others in the forums!Society of Robots copyright 2005-2014 forum SMF post simple machines