Fully autonomous calibration of parallel manipulators by imposing position constraint

Kinematic calibration is a process whereby the actual values of geometric parameters are estimated so as to minimize the error in absolute positioning. Fully autonomous methods of calibration are cost effective, fast and easy to implement. The paper presents a fully autonomous calibration technique that can be applied to a 6 degree-of-freedom fully parallel Hexa Slide manipulator. The main idea is to lock the mobile platform at a specific point with a device so that the platform has only 3 degrees of freedom, i.e. rotations about the locked point. The measurement data, however, is collected from six actuator sensors. This redundancy of sensory information is utilized for calibrating geometric parameters. Simulations show that the presented technique is the most effective with large range of orientation angles.