Dynamic and Control Simulation of Rotor Suspended by Three Radial AMBs Based on Multibody Dynamics

Multiple AMBs have greater bearing capacities than two radial AMBs but the multiple AMBs affect the system dynamics and control characteristics. The dynamic equations were developed for a three radial AMB system to calculate the critical speed and the unbalanced response of the three radial AMB system which are compared with those of a two AMB system. The model accounts for bearing misalignment and the effect of different support locations. The model is a flexible rotor with discs including a rigid body and Euler-Bernoulli beam based on an absolute nodal coordinate formulation and constraints based on the first type of Lagrange equation. The electromagnetic force on the AMB at each DOF is controlled by a PID control law in real time. The governing equations including the constraint equations are solved by the available differential algebraic equation solver.