Robot contouring performance study for nonconstrained process applications

The dynamic contouring errors attributed to a multiaxis robot performing a nonconstrained contouring process are discussed, and a way of interpreting this contouring error based on a relaxed performance measure is introduced. With this concept, multiaxis contouring errors can be reduced by matching axis delay times over a bounded frequency bandwidth rather than increasing loop gains in the axis controllers. A dynamic contouring error model is developed and used to establish axis-controller design criteria. Robust axis controllers are designed and implemented in a 6 d.o.f. Cartesian-type gantry robot. Test data are obtained to verify the performance of the controller design and to validate the error model