Regenerative Shock Absorber Research Articles

Modelling and Testing of a Hydraulic Regenerative Shock Absorber System

Modelling and Testing of a Hydraulic Regenerative Shock Absorber System

The Effect of Using Current Stabilizer to the Dynamic Characteristic of a Regenerative Shock Absorber

Most of the energy from the vehicle is wasted in the form of heat energy and vibration. On vehicles, the largest vibration occurs in the suspension system. The development of a mechanism which can recover the vibration energy and convert it into electrical energy, named Regenerative Shock Absorber (RSA), will be detailed in this paper. The prototype of RSA which consist of gear transmission and an electromagnetic type electric generator was studied and analyzed. Electrical circuit signal conditioner / stabilizer is added into the RSA system to stabilize the output current of the generator so that the generated electrical energy can be stored in the battery of 6 volts. The characteristics of the RSA are obtained by testing the value of the damping coefficient, the energy absorbtion capacity, and the generated electrical energy before and after going through a series of signal conditioner. Experiment was also performed by measuring the acceleration response time of the sprung and un-sprung suspension system that uses RSA with damping ratio value of 0.6. From this research, it is found that RSA design with stabilizer circuit can produce more stable electric current and voltage. The measurement results show the value of the electrical voltage output through the generator is fluctuating with an average value of 15 volts and a constant 6 volts output is obtained through the signal conditioning circuit. Furthermore, the dynamic response is obtained in the form of acceleration time-value of less than 0.2 m/s2 in a corresponding ISO 2631 standard is stated very comfortable.

A Comparative Study of the Damping Force and Energy Absorbtion Capacity of Regenerative and Conventional-Viscous Shock Absorber of Vehicle Suspension

This paper presents a comparative study of the damping force and energy absorbtion capacity of a typical conventional-viscous and a regenerative shock absorber for vehicle suspension. Regenerative shock absorber (RSA) is a shock absorber which can regenerate the dissipated vibration energy from vehicle suspension into electricity. In this research, a prototype of regenerative shock absorber was developed, its damping force and energy absorbtion capacity were tested, and the results were analized and compared with those of a typical conventional-viscous shock absorber. The regenerative and viscous shock absorber were compressed and extended in various excitation frequency using damping force testing equipment to obtain force-velocity and the force-displacement curves. The force-velocity and force-displacement curves indicate the damping force and energy absorbtion capacity of the shock absorber. The results show that the damping force of the typical-viscous shock absorber closed to linear at all exciation frequencies. For regenerative shock absorber, nonlinearity and large hysteresis area of the damping force occur at all excitation frequencies. Further, the energy absorbtion capacity of the typical-viscous shock absorber shows an elliptical area with the compression part bigger than the extension one, while those of the regenerative shock absorber shows an asymmetric square area, which indicates a smaller energy absorbtion capacity. These phenomena indicate the significant effect of implementing dry friction damper and elctrical damper to the characteristics of regenerative shock absorber.

Modeling and Analysis of Hybrid Shock Absorber for Military Vehicle Suspension

This paper deals with the design, modeling and analysis of a hybrid shock absorber for vehicle suspension. A specific design of frictional-electromagnetic-regenerative shock absorber is proposed. The hybrid shock absorber consists of the proposed frictional-electromagnetic-regenerative shock absorber assembled in parallel with a conventional-viscous shock absorber. The concept of hybrid shock absorber is proposed due to the following advantages: the regenerative shock absorber will recover some wasted vibration energy from the suspension into electrical energy to support the need for electrical energy of the vehicle, while the viscous shock absorber maintains the performance of suspension closed to its original suspension. The vehicle suspension system dynamic was mathematically modeled for three different types of suspension:1).Conventional suspension using viscous shock absorber; 2).Hybrid suspension using combination of 50% frictional-electromagnetic-regenerative shock absorberand50% viscous shock absorber; and 3).Full regenerative suspension using 100% frictional-electromagnetic-regenerative shock absorber. In this research, 6 wheels military vehicle (APC:Armour Personal Carrier) is chosen as the model due to the high possibility of applying regenerative suspension to the military/off road vehicle. Based on the mathematical models, performances of the vehicle suspension and the regenerated power from regenerative shock absorber (RSA) were simulated. The results were compared between the three types of suspension and discussed.

Electromagnetic Energy-Harvesting Shock Absorbers: Design, Modeling, and Road Tests

This paper presents the design, modeling, bench experiments, and road tests for a retrofit regenerative shock absorber based on a permanent magnetic generator and a rack-pinion mechanism for the purposes of energy harvesting and vibration damping. Results show that variable damping coefficients and the asymmetric feature in jounce and rebound motions are achieved by controlling the electrical load of the shock absorber. Improved efficiency and reliability are achieved by utilizing a roller to guide the rack and preload on the gear transmission to reduce backlash and friction. A peak power of 68 W and average power of 19 W are attained from one prototype shock absorber when the vehicle is driven at 48 km/h (30 mi/h) on a fairly smooth campus road.

Development and Analysis of a Regenerative Shock Absorber for Vehicle Suspension

Only10-16% of the fuel energy is used to drive the car-to overcome the resistance from road friction and air drag.One important loss is the dissipation of vibration energy by shock absorber of the vehicle suspension due to road irregularity, vehicle acceleration and deceleration.A prototype of regenerative shock absorber (RSA)was developed and its performance was studied.The prototype of RSA mainly consists of a gear transmission system, one way bearing and an electromagnetic generator.The RSA’s damping coefficient, its capacity to absorb energy and its ability to regenerate electrical energy were measured for various input frequencies, amplitudes and electrical loads. A quarter car model which consists of the developed RSA,a mass anda spring with specific damping ratio of ζ=0.6 and ζ=0.8 was tested. The test was done using a quarter car suspension test rig to investigate the performance of suspension which uses RSA and the generated electrical energy from RSA. The results are reported and discussed in this article.

Design and characterization of an electromagnetic energy harvester for vehiclesuspensions

During the everyday usage of an automobile, only 10–16% of the fuel energy is used todrive the car—to overcome the resistance from road friction and air drag. Oneimportant loss is the dissipation of vibration energy by shock absorbers in the vehiclesuspension under the excitation of road irregularity and vehicle acceleration ordeceleration. In this paper we design, characterize and test a retrofit regenerative shockabsorber which can efficiently recover the vibration energy in a compact space.Rare-earth permanent magnets and high permeable magnetic loops are used toconfigure a four-phase linear generator with increased efficiency and reduced weight.The finite element method is used to analyze the magnetic field and guide thedesign optimization. A theoretical model is created to analytically characterize thewaveforms and regenerated power of the harvester at various vibration amplitudes,frequencies, equilibrium positions and design parameters. It was found that thewaveform and RMS voltage of the individual coils will depend on the equilibriumposition but the total energy will not. Experimental studies of a 1:2 scale prototypeare conducted and the results agree very well with the theoretical predictions.Such a regenerative shock absorber will be able to harvest 16–64 W power at0.25–0.5 m s − 1 RMS suspension velocity.