Remote control of a mobile robot using distance-based reflective force

In this paper, a real-time obstacle avoidance method is discussed for a remote mobile robot controlled by a teleoperator. The method enables the remote user to drive the mobile robot without collisions. It consists of a real-time environment modeling algorithm using ultrasonic sensors, and a mobile robot control algorithm for obstacle avoidance. The former solves the limitations of the ultrasonic sensors such as noise sensitivity, poor directionality, and specular reflection for obtaining more accurate sensor data. Then the latter conducts wall or center following implemented by a fuzzy controller for obstacle avoidance using the environment model obtained by the previous algorithm. The command for obstacle avoidance is actually applied as a reflective force using a haptic device such as a force feedback joystick. The remote mobile robot, ROBHAZ-DT(RoBot in HAZardous environment-Double Track) developed by KIST(Korea Institute of Science and Technology), is employed as the mobile robot model. The normal and the maximum speed of the ROBHAZ-DT are 3.1 km/h and 7.2 km/h, respectively. The weight of the robot is 50 kg. Simulations with the ROBHAZ-DT model are carried out to verify the performance of the proposed method.