Identification and compensation of suspension disturbance for magnetically levitated rotary joints

For the multi-degree-of-freedom harmonic disturbance force/moment of the magnetically levitated rotor, a harmonic disturbance/disturbance force suppression method based on the eigenfrequency disturbance observer is proposed in this paper. First, a multi-freedom harmonic disturbance force/moment mechanism analysis is performed and its source is located. Then, a multi-degree-of-freedom eigenfrequency disturbance observer based on an adaptive discriminator is designed for closed-loop identification of the eigenfrequency disturbance forces of the magnetically levitated rotor by controlling its steady speed rotation. Then, the open-loop compensation current of each channel magnetic bearing is solved according to the multi-degree-of-freedom eigenfrequency perturbation observation results, so that the open-loop compensation electromagnetic force/moment and the perturbation force/moment form a balanced force/moment. Finally, tests were conducted on the rotating joint products, and the test results showed that the method can reduce the amount of magnetic levitation rotor levitation control fluctuation by more than 90% and improve the levitation stability by one order of magnitude.