This project consists of a robot balancing on two wheels. We use the 9-axis IMU LSM9DS0 to give us Accelerometer and Gyroscope data about the current angle and angular velocity of the robot. This data is then filtered using complementary filters and PID control to drive the two motors. The motors are controlled through digital outputs in their direction and their seepd by PWM using an H-bridge

Hardware used:

Micro-controller : Mbed NXP LPC1768. [http://developer.mbed.org/platforms/mbed-LPC1768/]

IMU : LSM9DS0 https://www.sparkfun.com/products/12636

H-Bridge: Polulu md08a https://www.pololu.com/product/713

Spark Fun RedBot Kit: https://www.sparkfun.com/products/retired/12032

Software Used:

LSM9DS0 library : http://developer.mbed.org/cookbook/LMS9DS0-IMU

Mbed API

Code:

This code uses a complimentary filter to reduce the IMU's inaccuracies. For more info check : http://www.pieter-jan.com/node/11

Assembly:

To reduce the center of gravity, the motors and the IMU chip are located as close to the wheels as possible with the IMU centered between the motors for a better balance. IMU to Mbed:

H Bridge to mbed

H Bridge to Motors : Left motor is to the left of the IMU chip and the right one is to the IMU's right.

Final Result:

This video shows the Balancing Bot in action.