Abstract
The hydraulic servo actuator system is generally dealt with as a second order delay element. The self-excited oscillation method has the advantage that it enables easy estimation of the dynamic parameters of the approximated second order transfer function without valuable measuring instruments such as a FFT analyzer. This study utilizing the self-excited oscillation method suggests the real-time identification algorithm. In order to demonstrate the method's effectiveness, the proposed method was experimentally compared with the frequency response characteristics. Results indicate that both method shows good coincident. It was also confirmed that when the supply pressure and additional torque are continuously changed in the hydraulic system, the damping coefficient and undamped natural frequency were updated on the PC monitor. In addition, amplitude and frequency correction coefficients are analytically obtained from the describing function considering the phase shift, and compared with the simulation results.
