| Fast Tool Servo (FTS) attracts more and more research interest on ultra-precision machining of complex surfaces, and the error correction in machine turning; the academic and engineering world pay more and more attention on it. As ultra-precision lathe spindle has some not inevitable non-stationary rotation, as well as cutting force disturbances and other uncertainties, which make improving the robustness of FTS become the urgent need to study and solve the problems.The FTS which is developed in our laboratory is driven by a voice coil motor, the physical model of the FTS is analyzed and established, and the identification of model parameters is discussed. The existing adaptive feedforward cancellation (AFC) control algorithm was improved for the inevitable non-stationary rotation of ultra-precision lathe spindle, and the cutting force disturbances and other uncertainties. The internal model control (IMC) is applied to design of the inner loop of AFC system; the robustness and the bandwidth of the AFC system is enhanced by adjusting the parameters of IMC. Combination of the characteristics between the AFC controller and the IMC, more resonators can be designed for tracking tool path and the resisting the interference as well as improving the performances of the whole control system.The AFC control system is analyzed and simulated based on acquisition of the FTS model parameters. The results show that the robustness and accuracy of the improved AFC algorithm proposed in this thesis are greatly improved.By studying the characteristics of AFC, in order to improve the accuracy of trajectory tracking of AFC and the ability to resist interference, AFC controller requires the greatest possible number of resonators with the interesting resonance frequency. The number of resonators is limited by the inner-loop bandwidth of the AFC system. Internal Model Control (IMC) can achieve no overshoot, high-bandwidth control performance. Since there is no high requirement about the accuracy of the inner loop, robustness and the bandwidth can improved at the expense of the steady-state performance of the inner loop in the allowable range.In the resonance frequency, the amplitude and the phase of the frequency response are one and zero respectively, but in other frequencies, the frequency response is not satisfactory. In the actual machining, there is instability of the spindle rotation. In order to satisfy the accuracy requirement in a certain frequency range, the inverse of the inner loop system is designed as feed-forward controller.The plant of this paper is a fast servo system (FTS) driven by a voice coil motor and guided by flexible hinges. For such institutions, the voltage balance equation and force balance equations are established, and analytical expression of the controlled object is derived after Laplace transformation. An identification experimental platform is build; a signal generator generates rectangular wave and sine wave as the excitation signals; the P-MAC collects input and output signals; the control object model is obtained and verified through MATLAB system identification tool box.According to the controlled object model, the IMC, PID and the lead-lag are applied to design the inner-loop system respectively. By comparative analysis of the performance characteristics of those three, the superiority of using the IMC is obtained.10 parallel resonators based on the spindle rotation are designed, and the corresponding parameters are determined. On this basis, a feedforward controller is designed to improve the control performances outside resonant frequency of the resonatorsBased on research of the AFC control system, the bandwidth and the robustness of the control system are improved by using IMC instead of the traditional PID and lead-lag control; the tracking control performance of AFC control system is enhanced due to that more harmonic component of the diamond turning tool path can be tracked.
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