Influences of the electromagnetic regenerative dampers on the vehicle suspension performance

Abstract

Conventional vehicle suspensions suppress vehicle vibrations by dissipating the vibration energy into unrecyclable heat with hydraulic dampers. This can be a considerable amount of energy which is worthy of attention for energy recovery. Electromagnetic regenerative dampers, or shock absorbers, are proposed to harvest this dissipated energy and to improve the fuel efficiency. The suspension dynamics with these regenerative dampers can be significantly different from the suspension dynamics with conventional dampers. First, different from conventional hydraulic dampers, the electromagnetic regenerative dampers have a significantly higher inertia, which is introduced by the electromagnetic generator. This has an important impact on the suspension dynamics. Second, the damping coefficient of electromagnetic dampers is related to the electric load connected to the output of the generator and can be controllable. Although various concepts have been proposed, the influences of these types of regenerative damper on the vehicle dynamics have not yet been thoroughly investigated. This paper models two types of rotational electromagnetic regenerative damper, with and without a mechanical motion rectifier, and analyzes their influences on the vehicle suspension performance in comparison with those of the conventional damper. The modeling in this paper also considers the case when the tires lose contact with the ground. Simulations were carried out with step road profile excitations and road profile excitations defined by the International Standardization Organization in order to evaluate the influences of the equivalent inertia mass and the equivalent damping coefficient. The results showed that, with an optimized equivalent inertia mass, both types of electromagnetic damper can achieve better ride comfort performances than a constant damper does. In addition, the mechanical motion rectifier mechanism can significantly improve the ride comfort and the road-handling performance of electromagnetic regenerative dampers by reducing the negative effect of the amplified generator inertia. In addition, the energy-harvesting potential of the presented dampers under road profile excitations defined by the International Standardization Organization was evaluated.

Design and Potential Power Recovery of Two Types of Energy Harvesting Shock Absorbers

“…As the movement in the vehicle suspensions is translational, the generation of a rotationally variable magnetic field requires a mechanism that converts translation into a rotation. These are well-known systems: rack-pinion [21][22][23], hydraulic [24][25][26][27][28][29], ball-screw [30][31][32][33], and some more exotic such as the "Linkage mechanism" [34], "Two-Leg motion" [35], or using flywheel drive [36]. All these systems have their own equivalent inertias, backlashes, and frictions affecting the dynamic behavior of the shock absorber and, therefore, the vehicle.…”

Energy harvesting from pavements and roadways: A comprehensive review of technologies, materials, and challenges

“…With the MMR‐EHRSA, an electric power of about 15 W could be harvested by a passenger car driven at 15 mph on a smooth road. Later on, they studied the effect of rotational electromagnetic regenerative dampers on the suspension performance and energy‐harvesting potential, with and without MMR. Guo et al compared conventional EHRSA and MMR‐based EHRSA.…”

A Comprehensive Review of the Techniques on Regenerative Shock Absorber Systems

“…The use of a step signal as the road displacement excitation input can evaluate the regenerative shock absorber's vibration response time and attenuation ability, thus giving the idea of how the vehicle responses to a single road bump. In their paper, Li and Zuo [122] compared the vehicle responses to a 10 mm step road displacement excitation for the vehicle suspension fitted with three regenerative shock absorbers in terms of weighted acceleration, dynamic/static tire force ratio, suspension deflection, harvested power and damping force.…”