Position estimation for mobile robot using in-plane 3-axis IMU and active beacon

In most cases, indoor environment is unstable because of floor condition, obstacles and room noise. So, to elevate accuracy of robot position data at unstable condition, a robot navigation system needs to apply diverse sensor fusion methods. This paper presents a navigation system consisting of a MEMS based digital in-plane 3 axis IMU (inertial measurement unit), an active beacon system and an odometer to obtain more precise robot position data and to monitor robot movement in realtime. Two accelerometers and one gyroscope compensate the nonsystematic errors of an odometer and perceive collision, bounce and slippage. Besides, fusing data of an IMU and an odometer can provide robot position data when an active beacon is losing its signal. When relative robot position data is unreliable, an active beacon system provides the absolute position data of the robot. To reduce noise of input sensors signal, low-pass filter and Kalman filter are applied. The sensor data from an in-plane 3-axis IMU, an odometer and an active beacon system are combined to obtain a precise navigation system. Results from two experiments in a real environment show that accuracy of robot position is elevated and that robot position data is not lost irrespective of robot's environment.