Study On Mobile Robot Navigation Control By Internal And External Sensor Data With Ultrasonic Sensor

A new method to combine internal and external sensor information for stable navigation of an autonomous land vehicle is presented. Usually, vehicle's relative position to its environment is available only at some time interval, because of low sampling rate of the sensor such as vision or ultrasonic sen- sor. Also, summation of wheel rotation is not reliable for position estimation due to wheel slippage. The presented method is an iterative method to minimize the estimation error by using both internal and external sensor information. Mechanical parameters of the vehicle such as tread, effective wheel diameter and slip ratio are also estimated together with position and orientation. This paper deals with a vehicle equipped with an ultrasonic range sen- sor as an external sensor. First, a. general principle of navigation using internal and extemal sensor is described. Secondly, simula- tion and experimental results are presented and evaluated. Both results show that the presented method is useful for guiding an autonomous land vehicle along a desired trajectory.