The measurement of spindle radial error motion is achieved based on target trajectory tracking (TTT). Error analysis of TTT method is performed in this paper. Target trajectory doesn’t contain information about axial error motion. The tilt error motion is included in the target trajectory. However, the tilt error motion is small enough to be ignored. The roundness error of the target trajectory is assessed to obtain the radial error motion of the spindle. The experimental results confirm that the proposed method can be applied to measure the radial error motion of a high-speed spindle having a maximum rotational speed of 6000r/m.
A method to measure the magnetic field inside the Giant Magnetostrictive Actuator (GMA) is proposed. Improved Preisach Model is applied to eliminate the unavoidable nonlinearity error in the measurement. The effect of temperature on measurement can be eliminated by double Fiber Bragg Grating (FBG) structure. The double-sagnac loop combined with Polarization Maintaining Fiber (PMF) is used to demodulate the center wavelength. Sensing model of the FBG is established to realize temperature compensation for the measurement system. Experiment results show that resolution of 2.1×10<sup>-4</sup> T can be achieved over a range of 127 mT, and the repeatability of overall measurement is 0.227%. Therefore, the proposed method can be used to measure the internal magnetic field of GMA effectively and reliably.
Whether velocity sensor can accurately acquire payload vibration information has become the most important factor that restricts vibration isolation performance. In order to get accurate sensor parameters, DC excitation method is used to measure the central frequency, damping ratio and sensitivity of inertial velocity sensor. The influence of different currents on the measurement accuracy of sensors such as response voltage, central frequency, damping ratio and sensitivity is analyzed, and the optimal current value is determined, which provides a powerful guarantee for obtaining accurate sensor parameters. Finally, the GS-11D sensor is used to carry out the experiment. The experimental results show that the relative error of the central frequency, damping ratio and sensitivity of the DC excitation method can meet the application requirements.