Multiple-degree-of-freedom sinusoidal vibration generation based on a hexapod platform

This article presents an active control strategy for generating multiple-degree-of-freedom sine and swept-sine vibration by using a hexapod platform as a shaker. In contrast to the typical frequency domain control approach of shaker controllers, the presented strategy is implemented in time domain, which brings an advantage of avoiding iteration, reducing the time required to adjust control signal. The novel strategy is combined by two parts: first, 36 finite impulse response filters are designed based on system identification, which compensate the multiple-input multiple-output system; then adaptive disturbance cancellation method is used, acquiring high-precision sine vibration. Swept-sine vibration generation is implemented by expanding the designed compensating filters. Experiments were carried out to evaluate the validity of this control strategy. The result showed that the time domain error is less than 1 mg, essentially being kept in the level of environment noise.