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Head of Mobile Robotics Laboratory
Department of Mechanical Engineering and Applied Mechanics.
The University of Michigan
This seminar will present two stand-alone but highly related talks. Each stand-alone talk includes a 5-minute video section.
This talk introduces a new approach to the design and control of a four-degree-of-freedom (4DOF) vehicle. This vehicle can travel sideways and it can negotiate tight turns easily. Existing 4DOF vehicles have been found difficult to control because of their overconstrained nature. These difficulties translate into severe wheel slippage or jerky motion under certain driving conditions. Our approach overcomes these difficulties by introducing compliant linkage, a new concept in the control and kinematic design of 4DOF 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. Experimental results are presented and show that control errors are effectively absorbed by the compliant linkage, resulting in smooth and precise motion.
This talk presents a new approach to accurate and reliable dead-reckoning with mobile robots. The approach makes use of special properties of our recently developed Multi-Degree-of- Freedom (MDOF) mobile platform, in which two differential-drive mobile robots (called "trucks") are physically connected through a compliant linkage. Using one linear and two rotary encoders, the system can measure the relative distance and bearing between the two trucks. During operation, both trucks perform conventional dead-reckoning with their wheel encoders, but, in addition, use information about their relative position to correct dead-reckoning errors. Our system, called Compliant Linkage Autonomous Platform with Position Error Recovery (CLAPPER), requires neither external references (such as navigation beacons, artificial landmarks, known floorplans, or satellite signals), nor inertial navigation aids (such as accelerometers or gyros). Nonetheless, the experimental results presented in this talk show one to two orders of magnitude better positioning accuracy than systems based on conventional dead-reckoning.
Host: Yangsheng Xu (xu+@cs)/James Osborn (oz@cs) Appointment: James Osborn (oz@cs)