Low-Frequency Active Vibration Isolation via Independent Modal Control and Harmonic Cancellation for Space Precision Payloads

High-resolution satellites have higher and higher requirements in microvibration isolation for space precision loads. The complex excitation of on-satellite loads such as low-frequency broadband and harmonic excitation poses great challenges to vibration isolation. In view of this, a low-frequency vibration control strategy integrating broadband and harmonic vibration cancellation is presented. Four passive isolators are used to connect the payload and eight electromagnetic actuators are used to provide orthogonal control forces. The system’s dynamic model with consideration of the auxiliary stiffness of the diaphragm spring and the friction in the actuator is built based on the Hamilton generalized variational principle and the vibration characteristics are analyzed. A broadband and harmonic vibration integrated suppression strategy with multiple channels is given, where the independent modal filtering and velocity-acceleration feedback method are applied in the broadband vibration attenuation, while the multichannel adaptive method is used in the harmonic vibration cancellation. The vibration attenuation efficacy of the introduced configuration for broadband and harmonic vibration is systematically evaluated. Both numerical simulations and experimental investigations confirm that the system effectively isolates broadband and harmonic vibration transmitted from the base to the payload. Notably, the system is capable of isolating vibration within the frequency range above 0.5 Hz and ensures attenuation exceeding 95% across the 0–100-Hz frequency range.