Self calibration of step-by-step based climbing robots

Fine manipulation of large industrial manipulators faces many problems due to well known error sources. Most climbing robots can be seen as mobile manipulators whose base is also moving across the climbing structure, and consequently adds some additional positioning errors. 3DCLIMBER is a serial mechanism pole climbing robot, developed at ISR-UC. The preliminary tests of the robot showed that it is particularly important to position the grippers precisely in the appropriate pose before grasping the structure. Otherwise the accumulating error will impair autonomous climbing process by forcing the operator to stop the operation after a couple of steps in order to calibrate the robot. This paper describes a self calibrating method proposed to measure and compensate these errors.