Modeling and disturbance compensation aided by multibody dynamics analysis in shaking table systems

Abstract

This paper presents an approach for modeling and disturbance compensation in multi-axis shaking table systems. Shaking table system is one of the facilities for seismic tests, where the accurate reproducibility of earthquake acceleration waveforms is essentially desired to evaluate the precise vibratory responses of specimen. However, the rotational motion due to overturning moment of specimen generates as a disturbance for the actuator control system, resulting in the lower reproducibility for the desired earthquake acceleration by deterioration of table motion performance. In order to compensate for the disturbance, at first, the simulator of shaking table including the specimen and control system is modeled using a multibody dynamics analysis including in a control CAD software. Based on the simulator, compensation signals that can cancel the disturbance are generated by an iterative learning control on the simulation, where the compensation signals are stored as time-series data. By using the compensation signals in the actual experiments, effects of the disturbance can be suppressed by the compensation signals in a feedforward control manner without repetitive actual excitations. The effectiveness of proposed control approach has been verified by experiments using a laboratory prototype.