A robust subspace based approach to feedforward control of broadband disturbances on a six-degrees-of-freedom vibration isolation setup

The contribution of this paper is two fold. First, the paper introduces a novel vibration isolation approach which uses a combination of passive and active vibration control techniques to provide additional design freedom. To illustrate the feasibility of the approach, a rigid-body hybrid six-degrees-of-freedom vibration isolation setup is presented. The objective of the setup is to investigate if the receiver structure can be isolated from the source structure by six hybrid vibration isolation mounts, such that disturbances induced by the source structure are isolated from the receiver structure. Vibration isolation is established by minimizing signals from six acceleration sensor outputs and by steering six piezo-electric actuator inputs. Our second contribution is that a subspace based state space fixed gain H2 controller is designed, implemented and validated. Real-time broadband feedforward control results are presented for frequencies between 0 and 1 kHz which show that an average reduction of 8.0 dB is achieved in the error sensor outputs in real-time.