A new large-scale posture measurement system based on a six-laser tracer multilateral method

Abstract

To realize high-accuracy posture measurement in large scale, a posture measurement system is proposed in this study based on a six-laser multilateral method, mainly composed of six laser tracers and three reflectors-a different number of laser tracers tracks each mirror. But in this state, the system is positive definite, and it cannot achieve the system parameters by self-calibration. To solve this problem, a stepwise calibration method to obtain the system parameters by three-step calibration is presented. Simulations and experiments are carried out to verify the effectiveness of the proposed method. The experimental results show that the posture errors are distributed over [−13.6″, 6.6″] when the measurement range is [5 m, 7 m], which shows that the new measurement system has a high posture measurement accuracy in large scale.

Influencing factors of rotary table geometric error measurement using four-station laser tracers

“…In some cases, the optimum layout cannot be achieved, although it can be found theoretically because of the physical restrictions in machine tools [11]. The cat's eye or reflector plays a vital role in ensuring the measurement accuracy in the installation location [12] and center offsets to obtain the lowest divergence angle of the reflected laser beam [13]. Accordingly, the center offsets will have a direct negative effect on the measurement results [14].…”

“…In addition, the variation in the measurement range will affect the measurement accuracy [12] and the uncertainty of the length measurement of the laser tracer [15]. The measurement points should not approach the plane defined by the three laser trackers in the four-tracker method to limit measurement errors [16].…”