High precision measurement of acceleration levels is required to allow active control for vibration isolation platforms. It is necessary to propose an accelerometer configuration measurement model that yields such a high measuring precision. In this paper, an accelerometer configuration to improve measurement accuracy is proposed. The corresponding calculation formulas of the angular acceleration were derived through theoretical analysis. A method is presented to minimize angular acceleration noise based on analysis of the root mean square noise of the angular acceleration. Moreover, the influence of installation position errors and accelerometer orientation errors on the calculation precision of the angular acceleration is studied. Comparisons of the output differences between the proposed configuration and the previous planar triangle configuration under the same installation errors are conducted by simulation. The simulation results show that installation errors have a relatively small impact on the calculation accuracy of the proposed configuration. To further verify the high calculation precision of the proposed configuration, experiments are carried out for both the proposed configuration and the planar triangle configuration. On the basis of the results of simulations and experiments, it can be concluded that the proposed configuration has higher angular acceleration calculation precision and can be applied to different platforms.

The relative position between the laser beam and the nozzle is controlled by laser-focus-controlled magnetic actuators to achieve non-coaxial laser cutting and improve laser cutting efficiency. In this paper, a 3-DOF (degrees of freedom) magnetic actuator is designed to solve the inconsistency of the laser beam focus and the nozzle focus in off-axis laser cutting. A mixed sensitivity robust controller is designed, and its simulation analysis and experimental research are carried out. First, the kinetic mathematical equations are established according to the structure of the actuator. Then, a mixed sensitivity robust controller is designed and analyzed using MATLAB/Simulink. The control performance is simulated and analyzed under 20% parameter variation and pulse disturbance with an uncertain mathematical model and external disturbance, respectively. Finally, the experimental study of the step response of the actuator is carried out. The experimental results show that the step response of the actuator in the Y, X, and θ directions can quickly reach the steady-state value. Furthermore, the steady-state error in the X is 1.6%; the steady-state error in the Y is 0.39%; the steady-state error in the θ is 0.45%. Their errors are all less than 0.025 mm, so they meet the position performance requirements. It can provide technical support for laser off-axis cutting.