Sensor-less parameter estimation of electromagnetic actuator for shunt damping

Abstract

Electromagnetic shunt damping is a sensor-less passive damping technique using an electromagnetic actuator. The accurate values of the parameters of the system are essentially required for designing a controller in the damping technique. This paper proposes a parameter estimation method of an electromagnetic actuator attached to a mechanical structure in order to use for electromagnetic shunt damping. The electromagnetic actuator attached to the structure is modeled as the system including the mechanical and electrical systems which are connected by the electromechanical coupling coefficient. This paper points out a remark on the estimation: The frequency response of the electrical admittance especially neighborhood the natural frequency of the mechanical structure shows an electro-mechanically resonant feature, which does not appear in the pure electrical system without the electromechanical coupling. By applying least squares method to the frequency response data of the electrical admittance neighborhood the natural frequency, the parameters of the mechanical system and the electromechanical coupling coefficient as well as the electrical parameters can be estimated. The proposed estimation method requires only measurements of the frequency response of the electrical admittance across the terminals of the electromagnetic actuator. Therefore, both the parameter estimation and the electromagnetic shunt damping are possible to perform without any displacement or velocity sensors, or any additional actuators. In order to verify the effectiveness of the proposed method, the experiments of parameter estimation and of electromagnetic shunt damping are performed. The experimental results show that the proposed method is effective to estimate the parameters of the electromagnetic actuator without use of any other sensors.

Sensorless parameter estimation of electromagnetic transducer considering eddy currents

“…The composite system consists of three subsystems: a mechanical system, an electromechanical coupling system, and an electrical system. In many vibration control systems, a mechanical system is modeled by a simple mass-spring-damper system coupled to an electromagnetic transducer [22,31,38,39], as shown in Fig. 1.…”

“…1. The equation of motion is given by An electromechanical coupling system is given by the following pair of equations under suitable assumptions [22,23,31,36,38,39]:…”

“…The parameter estimation is formulated by the weighted nonlinear least-squares method; in addition, the selection of the initial estimates for the numerical optimization is discussed in detail. The preliminary idea of this paper has been presented in [38,39], in which the method for the sensorless parameter estimation of an electromagnetic transducer is introduced only for the self-inductance to construct the impedance model. Inspired by the previous works [8,9,10,11,40], the present paper introduces novel impedance models that consider eddy currents.…”