Ehsan Asadi

A new adaptive hybrid electromagnetic damper: modelling, optimization, and experiment

This paper presents the development of a new electromagnetic hybrid damper which provides regenerative adaptive damping force for various applications. Recently, the introduction of electromagnetic technologies to the damping systems has provided researchers with new opportunities for the realization of adaptive semi-active damping systems with the added benefit of energy recovery. In this research, a hybrid electromagnetic damper is proposed. The hybrid damper is configured to operate with viscous and electromagnetic subsystems. The viscous medium provides a bias and fail-safe damping force while the electromagnetic component adds adaptability and the capacity for regeneration to the hybrid design. The electromagnetic component is modeled and analyzed using analytical (lumped equivalent magnetic circuit) and electromagnetic finite element method (FEM) (COMSOL® software package) approaches. By implementing both modeling approaches, an optimization for the geometric aspects of the electromagnetic subsystem is obtained. Based on the proposed electromagnetic hybrid damping concept and the preliminary optimization solution, a prototype is designed and fabricated. A good agreement is observed between the experimental and FEM results for the magnetic field distribution and electromagnetic damping forces. These results validate the accuracy of the modeling approach and the preliminary optimization solution. An analytical model is also presented for viscous damping force, and is compared with experimental results The results show that the damper is able to produce damping coefficients of 1300 and 0–238 N s m−1 through the viscous and electromagnetic components, respectively.

Multi-objective optimization of a hybrid electromagnetic suspension system for ride comfort, road holding and regenerated power

This paper reports work on the optimization and performance evaluation of a hybrid electromagnetic suspension system equipped with a hybrid electromagnetic damper. The hybrid damper is configured to operate with hydraulic and electromagnetic components. The hydraulic component produces a large fail-safe baseline damping force, while the electromagnetic component adds energy regeneration and adaptability to the suspension. For analyzing the system, the electromagnetic component was modeled and integrated into a 2DOF quarter-car model. Three criteria were considered for evaluating the performance of the suspension system: ride comfort, road holding and regenerated power. Using the genetic algorithm multi-objective optimization (NSGA-II), the suspension design was optimized to improve the performance of the vehicle with respect to the selected criteria. The multi-objective optimization method provided a set of solutions called Pareto front in which all solutions are equally good and the selection of each one depends on conditions and needs. Among the given solutions in the Pareto front, a small number of cases, with different design purposes, were selected. The performances of the selected designs were compared with two reference systems: a conventional and a nonoptimized hybrid suspension system. The results show that the ride comfort and road holding qualities of the optimized hybrid system are improved, and the regenerated power is considerably increased.

Development and investigation of a semi-active polar planar haptic interface using the digital resistance map concept

The growing demand for haptic technologies in recent years has motivated novel approaches in developing haptic interfaces and control algorithms. Semi-active haptic interfaces, in general, have the advantage of addressing safety concerns which adversely affect their active counterparts. This paper presents the development of a planar semi-active haptic interface using magnetorheological (MR) dampers. The ability of MR dampers to produce controllable resistance forces is the key reason for their utilization in the proposed haptic interface. The proposed planar semi-active haptic interface consists of linear and rotary MR dampers. Each of the MR dampers is modeled experimentally using the Bouc‐Wen model. A haptic rendering algorithm called the digital resistance map (DRM) is also developed to control MR dampers. DRM is a high-fidelity haptic rendering algorithm, and proved to be effective to create comprehensive force feedback for operators. MATLAB/Simulink R is used for implementing several DRM scenarios for generating haptic enabled virtual environments. The experimental results demonstrate the effectiveness of the proposed haptic interface and rendering algorithm.