Oscillation Damping With Input Shaping in Individual Metering Hydraulic Systems

Motion of heavy loads with hydraulic or electrical drive systems cause oscillations, which reduce the position accuracy and cause wear to the mechanical system. Input shaping of the control input signal can avoid the excitation of the resonant frequency. A common technique is to use a notch-filter that is tuned to suppress this frequency. In this work the possibility to synthesize a notch filter with an all-pass filter is used. Splitting the filter into two parts allows to control two separate inputs of a push/pull system, in the actual case a hydraulic system with individual meter-in and meter-out valves (or separate meter-in/meter-out, SMISMO). An additional design parameter allows to tune for specific property of the drive, in our case avoiding low pressure and reduce the danger of cavitation. Furthermore, it is demonstrated how to replace the all-pass filter with a simple time delay, which enables the processing on a low-cost embedded system without numeric processor. The results are demonstrated in simulation.