An accurate 6-DOF dynamic measurement system with laser tracker for large-scale metrology

To develop a highly adaptable real-time 6-degree-of-freedom (6-DOF) measurement system for large precision engineering, high precision and good dynamic performance are the key problems to be solved. In this paper, a novel 6-DOF total measurement system is proposed, which is composed of a vision-inclination combining pose measurement target sensor (PMTS), a built-in strapdown inertial navigation system (SINS) and a cooperative laser tracker as the base station. And a precise mathematical model is established by the measured data from laser tracker, PMTS and SINS to the 6-DOF variables output. Meanwhile, a turntable-based calibration method for the PMTS and the inertial measurement unit (IMU) is proposed. More importantly, to solve the fatal problem that the inclinometer failed under dynamic conditions, a Fault-tolerant Kalman filter (FKF) based on residual chi-square test is introduced. Finally, comparative experiment with Leica T-MAC is conducted to verify the precision and dynamic performance of proposed methods.