A multi-degree-of-freedom orientation measurement methodology with laser detection

The advance of robotics, actuators and manufacturing technology motivates the research on measurement of multiple degree-of-freedom (DOF) rotational motions. A novel laser-based high-precision spherical displacement sensing methodology has been proposed in this paper. The laser detector is utilized to measure the distance from the target to the detector itself on several light spots, and thus to calculate the rotation angle of the rigid body in three directions. As there is no physical contact between the laser detector and the moving rigid body, additional mass/moment inertial and friction exerted on the rotor can be avoided, and thus the working efficiency of the moving part can be improved. The algorithm of orientation angles has been derived. Experimental apparatus has been developed to evaluate the working performance of proposed 3-DOF laser-based measurement methodology. The comparison between experimental and analytical results shows that the laser-based orientation measurement method can achieve high-precision performance. The measurement precision and speed of the the laser-based angular displacement measurement method can be improve further by increasing the slot density on the rigid body and using new models of laser detectors.