Modeling and Control of a Six Degrees of Freedom Maglev Vibration Isolation System

Abstract

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.

Finite-time adaptive control for microgravity vibration isolation system with full-state constraints

“…Edberg et al [14] used a series-level control loop with position feedback and acceleration feedback acting together with variable gain parameters, when the displacement error is small, a small gain parameter is applied, and when the displacement error becomes large, a set of high gains is changed to limit the float travel to avoid collisions. Wu et al [15] proposed a double closed-loop control strategy composed of an absolute movement controller and a relative movement controller, and designed a low-pass filter and a band-pass filter to switch the control objectives. In addition, many studies have also transformed this problem into a multi-objective optimization problem, using H 2 [16,17], and hybrid multiobjective control [18,19] to achieve the control objectives.…”

Design and Analysis of a 2-DOF Electromagnetic Actuator with an Improved Halbach Array for the Magnetic Suspension Platform

“…The microgravity environment of space stations has opened up a new frontier for experimental research in materials science, basic physics, life science, and biotechnology [ 1 ]. However, the conditions of acceleration-sensitive experiments are usually not satisfied because of the low-frequency and high-frequency micro-vibrations produced by gravity gradients, orbital maneuvers, attitude control, equipment operation, and astronaut activities in the space laboratory [ 2 , 3 , 4 , 5 ].…”

Grey relation analysis of natural frequency and semi-active robust optimal control of a multi-dimensional isolator based on parallel mechanism and magneto-rheological damper

“…Through optimization, simulation and experiments, the vibration isolation performance exhibited effectiveness in low frequency range. Wu et al 2 introduced a six degrees of freedom vibration isolator based on maglev actuators. The nonlinear dynamic equation with Lorenz force was deduced.…”