Control and kinematic design of multi-degree-of freedom mobile robots with compliant linkage

Mobile robots (unlike automated guided vehicles) usually rely on dead-reckoning between periodic absolute position updates and their performance is diminished by excessive wheel slippage. This paper introduces compliant linkage, a new concept in the control and kinematic design of multi-degree-of-freedom (MDOF) mobile robots. As the name implies, compliant linkage provides compliance between the drive wheels or drive axles of a vehicle, to accommodate control errors which would otherwise cause wheel slippage. The concept of compliant linkage was implemented and tested on a 4-DOF vehicle built at the University of Michigan's Mobile Robotics Lab. Experimental results show that control errors are effectively absorbed by the linkage, resulting in smooth and precise motion. The dead-reckoning accuracy of the compliant linkage vehicle is substantially better than that reported in the literature for other MDOF vehicles; it was found equal to, or even better than that of comparable 2-DOF vehicles