Error Compensation Method for 3-D Postural Transformation Monitoring Using Cooperative Goniometers

In response to the increasing demand for accurate monitoring of 3-D positional transformation of target loads, and also to overcome the errors due to the deformation of the support structure itself at the point of deployment of multiple devices. The present study proposes a compensation method for 3-D optical angle measurement systems based on multidevice collaboration. Three-dimensional vectors are used to characterize the positional transformation of the target load, and the coordinates of the spot on the detection surface of the goniometers are derived. Based on the spot coordinates of the three goniometers, the theoretical attitude transformation value of the target load is inverted by means of the Levenberg-Marquardt algorithm. The target attitude transformation values are compared between the three goniometer devices for cooperative compensation monitoring and between only two devices for monitoring. The average errors of the angular measurements in the a-, b-, and c-directions are less than 0.044, 1.069, and 0.03 in, respectively, which are 6.1, 11.6, and 7 times lower than those before compensation. After verification of the simulation of the actual situation, the changes in the relevant variables of the goniometer system and the measured changes in the reference autocollimator are consistent with the accuracy of the reference autocollimator. It is concluded that the measurement computing accuracy of the goniometer system is not lower than that of the reference autocollimator, which verifies the practicability and effectiveness of the compensation method proposed.