This paper presents the five degree-of-freedom (5-DOF) control of an electrodynamic MAGLEV suspension with active control of the levitation coils. A sled with built-in permanent magnets moves past an array of fixed coils to generate Lorentz forces that provide lift and guidance. When active control of the levitation coil currents is implemented, multi-DOF trajectory control can be achieved, leading to stable electrodynamic levitation that can actively reject disturbances independently of sled speed. This paper shows successful control of the multi-DOF trajectory of a passive sled by active control of the coil currents, using both a sliding mode controller with nonlinear input mapping from coil currents to levitation forces, and a multi-DOF nonlinear observer. The paper also compares the use of look up tables versus analytical models of the magnetic field density used to estimate the magnetic forces and torques acting on the sled. The performance of the proposed approaches is demonstrated experimentally.

5-DOF Real-Time Control of Active Electrodynamic MAGLEV

This paper explains the design of Servo State Feedback Controller and Feedback Linearization for Magnetic Levitation Ball System (MLBS). The system uses feedback linearization to change the nonlinear model of magnetic levitation ball system to the linear system. Servo state feedback controller controls the position of the ball. An integrator eliminates the steady state error in servo state feedback controller. The parameter of integral gain and state feedback gains is achieved from the concept of Coefficient Diagram Method (CDM). The CDM requires the controllable canonical form, because of that Matrix Transformation is needed. Hence, feedback linearization is applied first to the MLBS then converted to a controllable form by a transformation matrix. The simulation shows the system can follow the desired position and robust from the position disturbance. The uncertainty parameter of mass, inductance, and resistance of MLBS also being investigated in the simulation. Comparing CDM with another method such as Linear Quadratic Regulator (LQR) and Pole Placement, CDM can give better response, that is no overshoot but a quite fast response. The main advantage of CDM is it has a standard parameter to obtain controller’s parameter hence it can avoid trial and error.

CDM Based Servo State Feedback Controller with Feedback Linearization for Magnetic Levitation Ball System

Fuzzy sliding mode control based on PSO for magnetic levitation positioning stage

Magnetic levitation (Maglev) systems are highly beneficial in industrial applications owing to their reduced power consumption, increased power efficiency and reduced cost of maintenance. Common applications include Maglev power generation (e.g., wind turbine), Maglev trains and medical devices (e.g., magnetically suspended artificial heart pump). This paper presents the exact input-state feedback linearisation of a nonlinear Maglev system using estimated states. The observed states from a nonlinear dynamic full-order observer are used as inputs to the controller where the control law does not need to be expressed in terms of all measured variables. Then, a linear quadratic regulator is used as an optimal controller for the linearised model to guarantee the stability of the observer-based control scheme and, finally, a tracking controller for magnetic levitation is derived.

Nonlinear full-order observer-based controller design for active magnetic levitation via LQR-feedback linearisation

This paper shows the implementation of Fuzzy Control techniques on a small Magnetic Levitation system. The analyzed application is a study problem of a non-linear and unstable system. Fuzzy control is an appropriate alternative for those cases where modelling the system is complicated, mainly due to the mathematical complexity of the model. The advantage of Fuzzy techniques is that any additional adjustment in the system only requires modifying the different fuzzy rules implemented, instead of redesigning the entire associated controller again. The control implemented here is made up of two feedback loops (position and current variables). A Hall sensor has been used to determine the position of the sphere to be levitated. Matlab/Simulink has been the software used for the development of the model and its simulation. In this way, the dynamic response of the system has been studied. The results and the different figures of merit obtained are shown by simulating the model presented. The initial objectives have been satisfactorily achieved.

Design of a Fuzzy-Controller for a Magnetic Levitation System using Hall-Effect sensors

Magnetic levitation (Maglev) systems make significant contribution to industrial applications due their reduced power consumption, increased power efficiency and reduced cost of maintenance. Common applications include Maglev power generation (e.g. wind turbine), Maglev trains and medical devices (e.g. magnetically suspended artificial heart pump). This paper proposes fuzzy sliding-mode controller ‘FSMC’ with a nonlinear observer been used to estimate the unmeasured states. Simulations are performed with nonlinear mathematical model of the Maglev system, and the results show that the proposed observer and control strategy perform well.

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A. M. Benomair

Papers

Fuzzy sliding control with non-linear observer for magnetic levitation systems