A Novel Method of Improving Non-Sinusoidal Periodic Waveform in Force Excitation Control System

A non-sinusoidal periodic waveform, such as a triangle wave, is often used as the testing input signal in force excitation control systems. Limited by the bandwidth of the system, the output waveform is often distorted, and the dynamic tracking accuracy is reduced. As an alternative to a hardware upgrade, a novel method of improving the tracking precision of the non-sinusoidal periodic waveform in the force excitation control system is presented. A key technique of the method is the adjustment of the spectrum of the non-sinusoidal periodic waveform in advance according to the frequency response characteristic of the control system. The working principle of the frequency-box regulator, the formula derivation, and the operation steps are explained. Simulations and tests are conducted to confirm the effectiveness of the method. The results show that the novel method (frequency-box regulation) works well in the force excitation control system.