Visual dead-reckoning for motion control of a Mecanum-wheeled mobile robot

Given an omni-directional mobile platform using four Mecanum wheels requires further a capability to be programmed to achieve various motion behaviours and intelligence. This paper describes an undergraduate solution to the problem involving both hardware and software developments. With a path following behaviour as the aim, the research focused predominantly upon; sensors for dead-reckoning, motor drive, closed-loop feedback control, and microcontroller interfacing and programming. A four channel high power MOSFET and relay H-Bridge driver circuit board was designed for driving four motors. Two optical mice were attached to the front and rear of the robot giving positional feedback for closed-loop control and dead-reckoning for navigation. A Mitsubishi M16C/62 microcontroller was interfaced to these TTL compatible devices and subsequently programmed to implement various robotic behaviours. A closed-loop control scheme using three independent PID controllers was implemented to follow three degrees-of-freedom motions, i.e., x- and y-movement and rotation motions. The path following performance of the robot was tested in both openloop and closed-loop modes and the optical mice were found to be a promising but inexpensive sensor, providing dead-reckoning for robot motion control. (C) 2003 Elsevier Ltd. All rights reserved.