Electromagnetic Shock Absorber Research Articles

Study of the operation of active suspension with magnetic fluid-less shock absorbers

The article presents the structure of an active suspension system for a commercial vehicle aimed at enhancing system performance. Solutions for integrating electromagnetic dampers into an intelligent active suspension system are identified. The behavior of the suspension system under challenging road conditions is examined. A block diagram of the active suspension system with a controller is provided. The article is published based on the findings of a research project conducted as part of a grant competition for scientific research projects by the teaching staff of Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU) in 2024. Keywords magnetic shock absorbers, electromagnetic shock absorbers, suspension, damping, modeling

Analysis of damping multi-mode switching control of semi-active suspension based on digital controlled hydraulic cylinders group

In order to improve the ride comfort of vehicle suspension, this article proposes a damping multi-mode semi-active suspension system and its control method. The semi-active suspension takes a hydraulic electromagnetic shock absorber based on a digital controlled hydraulic cylinders group as the core, and realizes the switching of multiple damping modes by controlling the on-off statuses of three groups of switch solenoid valves, thus making the semi-active suspension have the characteristics of damping multi-mode adjustable. The damping characteristics corresponding to the single damping mode are verified through the prototype bench test of the shock absorber principle. On this basis, the semi-active suspension model of the vehicle is established, and a multi-mode switching control strategy of suspension damping using fuzzy control is designed. The filtered Gaussian white noise is used as the random road excitation for simulation. The simulation results show that compared with the traditional passive suspension and the semi-active suspension based on skyhook control, the damping multi-mode semi-active suspension based on the digital controlled hydraulic cylinders group can realize the switching of multiple damping modes, have good damping performance, and help to improve the vehicle ride comfortable capability.

Design and Performance Analysis of a New Lightweight Rotor Adaptive Electromagnetic Shock Absorber for Armored Vehicles

Design and Performance Analysis of a New Lightweight Rotor Adaptive Electromagnetic Shock Absorber for Armored Vehicles

Damping Characterization of Electromagnetic Shock Absorbers by Considering Engagement and Disengagement

Damping Characterization of Electromagnetic Shock Absorbers by Considering Engagement and Disengagement

Design of a 120 W Electromagnetic Shock Absorber for Motorcycle Applications

Based on the shock absorber size and power and power density limitations in motorcycle application, a linear permanent magnet machine for a regenerative suspension system that recovers the kinetic energy originating from shock absorber vibration is investigated. To achieve the target power of 120 W, several design parameters were investigated. The eight-slot eight-pole combination was used due to its high power density. A hybrid permanent magnet structure was implemented which was a combination of a classical Halbach array and iron spacers. In addition, the dimensions of the permanent magnet, and stator inner radius were parametrically studied to enhance the air-gap flux density and coil volume, which are the main factors affecting performance. The detailed design generated 124 W of average power under the rated condition, assuming a vibration speed of 0.157 m/s. Despite the satisfaction of the output power and power density, the large magnetic force caused by the interaction between the iron core and permanent magnet is the main drawback of this design, which has a negative impact on driving safety and comfort. To commercialize the suggested device, additional studies will focus on size, electromagnetic reduction, as well as road test performance.

A robust hybrid generator for harvesting vehicle suspension vibration energy from random road excitation

Existing energy harvesters are mostly designed into the electromagnetic shock absorbers to replace the original dampers in automotive suspension systems, possibly deteriorating sprung mass acceleration when the energy harvesters are in trouble. Therefore, this study proposed a hybrid generator based on the sliding-mode triboelectric nanogenerator (S-TENG) and electromagnetic generator (EMG) to harvest the suspension vibration energy without replacing the original damper and deteriorating sprung mass acceleration. First, the patterned polyimide (PI) films were prepared to solve the challenge of the poor durability of the S-TENG due to material wear. The results showed that the wear mass loss of PI film diminished with the decrease of pillar pitch, and the wear mass loss of P2 film was only 37% of that of the smooth one. Furthermore, whether the patterned surface could improve the electrical output of the S-TENG depended on the pattern parameters, which was a departure from the common view that any pattern could enhance triboelectrification. In this paper, P2 was the optimal textural parameter for improving the durability and electrical output of the S-TENG, which could provide a texture design reference for the S-TENG. Second, the hybrid generator charged a 4.7 μF capacitor to 18.05 V in 60 s, and the contribution ratio of charging voltage of the S-TENG component increased with extended charging time. Finally, the hybrid generator moved together with the original shock absorber without a noticeable impact on sprung mass acceleration, which can make the accelerometer self-powered at different random road excitations.

Characterization and implementation of a double-sided arm-toothed indirect-drive rotary electromagnetic energy-harvesting shock absorber in a full semi-trailer truck suspension platform

Heavy goods vehicles (HGVs), which usually travel on rough and dirt roads, have great potential for harvesting the dissipated energy during the damping routines. Thus, this study explores the benefits of energy-harvesting shock absorbers when integrated into HGVs due to their vibration's densities. The double-side arm-toothed indirect-drive rotary electromagnetic energy-harvester is consequently proposed. The contribution lies in that, (a) it could be the first time applying a double-side arm-toothed indirect-drive rotary electromagnetic energy-harvesting shock absorber in an articulated truck semi-trailer model; (b) complete characterization of the arm-toothed indirect-drive regenerative damper via parametrical conflict and sensitivity analyses; (c) quantitative assessment of the total harvestable power and voltage of the proposed 12 double-sided arm-toothed regenerative truck shock absorbers; and (d) Taguchi method simulation to perform a sensitivity ranking analysis of the truck influential parameters considering the harvested power, the truck ride quality and road holding criteria. The results indicate that the truck harvested an average power of 0.33, 1.33, 5.24, 21.3 W under road Classes of B, C, D, and E at 120 km/h. Regardless of the frequency range, the truck suspension can still maintain a comfortable driver ride index while simultaneously harvest power via the 12 integrated double-sided arm-toothed regenerative dampers.

Энергетические показатели электромагнитного гасителя колебаний транспортного средства

The creation of an electromagnetic shock absorber system is necessary taking into account such parameters of the vehicle and operating conditions as the quality of the roadway, the grades, and the weight and size of the vehicle. A mathematical simulation model of the vehicle was developed to determine energy indicators in various road sections. The MATLAB Simulink programming environment was chosen to create the most practical and functional simulation model. A number of experiments were carried out using various parameters of the vehicle, types of roadways and driving cycles. Simulation results allow obtaining basic characteristics of electromagnetic damper of the selected vehicle, on the basis of which a linear electromagnetic damper shock absorber will be calculated. System energy efficiency was determined when using a vehicle on roads having a different road surface evenness index.

Transmission and energy-harvesting study for a novel active suspension with simplified 2-DOF multi-link mechanism

In this paper, a new energy-regenerative suspension system with a simplified multi-DOF mechanism was proposed. The research firstly focuses on characteristics of the transmission and conversion analysis, and energy recovery calculation. Then the relationship between the vibration amplitude and the rotation angle is computed and simulated. The dead angle of motion is found. A novel parameter K is proposed to describe the outer profile envelope of the linkages for the first time, which provides a potential reduction for the control matrix dimension. A 2-DOF suspension model, integrated with the multi-link rotating electromagnetic regenerative shock absorber, is built, simulated, and analyzed. The kernel simulation results are validated by experiments at last. Driving on Class B road, the results show that the energy-regenerative suspension controlled by the LQG algorithm is 20.56% smaller than the passive suspension in Body Acceleration; the energy regeneration efficiency is 14.28%, and the self-supply efficiency is 54.66%. Comparing to the ball-screw structure, we increase the energy harvesting ratio by 21.43% with similar control effects. The research provides new ideas for suspension design and control, reduces energy consumption, and improves ride comfort and driving stability as well.

The Effect of Vibration Energy Harvester Mechanism Toward the Shock Absorber Efficiency

The installation of vibration energy harvester[1], [2] mechanism type Electromagnetic Regenerative Shock Absorber (ERSA)[3][4] on vehicles can increase their energy efficiency. They will produce a new energy sources which can be used to fulfil their energy needed. However, this mechanism installation can change the shock absorber efficiency value which affect the convenience of driving itself. This research used experimental method which the ERSA mechanism installed on the usual shock absorber. ERSA is designed to be able to capture translation movement from the shock absorber and change it to electrical energy like of linear generator mechanism. From the test, the efficiency increased 0.8-1.2% on each wheel. The increase of efficiency value thought is electromagnetic damping force which was produced by ERSA mechanism. From the result of the test, it can be concluded that ERSA installation is not very impactful towards efficiency value of shock absorber because the value is still below 10%.

Comparative Study of Novel Doubly-Fed Linear Switched Flux Permanent Magnet Machines With Different Primary Structures

To enhance the thrust force density and move a part of copper loss from the primary to the secondary of linear switched flux permanent magnet machines (LSFPMMs), this paper proposes a novel kind of doubly-fed LSFPMMs (DFLSFPMMs) by adding another set of armature winding on the secondary of LSFPMMs. The design and working principles of the new winding are analyzed first. It is found that the optimal coil pitch depends on the primary structure. Then, the parameters of DFLSFPMMs with U-core, C-core, E-core, and multi-tooth primary structures are globally optimized, and their electromagnetic performances are investigated by 2D finite element method. The result shows that the average thrust force of U-core DFLSFPMM is 30% higher than that of conventional LSFPMM counterpart, and it is also 23%-29% higher than those of DFLSFPMMs with other three primary structures. Besides, the U-core machine with tubular structure is analyzed for the potential application of electromagnetic shock absorbers, which shows the U-core DFLSFPMM has 10% higher peak-to-peak damping force than linear spoken-type PM machine. Finally, a prototype of U-core DFLSFPMM is manufactured and tested to validate the analysis.

Development of the Electromagnetic Regenerative Shock Absorber as an Energy Harvesting Tool for Vehicles

This research is a development of previous research entitled "Designing Regenerative Shock Absorber as a Vibration Energy Harvesting Tool on Vehicles" in the PUPT scheme funded by PNBP UNP 2017. In this study optimization of design oriented to energy generation was carried out while also paying attention to aspects driving comfort that might change due to the installation of a harvesting energy mechanism. One aspect of the change occurred in the type of magnet used, namely a ring type magnet with a type of neodymium material.From the test results obtained by changing the value of the efficiency of the shock absorber after the ERSA mechanism is installed by 2%, this condition also has an impact on the dissimilarity of the attenuation value obtained by 2% for the front-rear (left) and (right) wheels. In terms of generation voltage obtained the maximum generation voltage obtained is 25,600 mV. Based on the data obtained, it needs further development ERSA, especially in the aspect of the electromagnetic mechanism to optimize the generation of electrical energy.

The physical model of the vehicle electromagnetic shock absorber

This article presents the development of an electromagnetic absorber physical model. The developed system is designed for physical experiments realisation. Estimated experiments results are necessary for the suspension operating parameters adjustment. Research need is caused by the stochastic nature of the road unevenness and rolling stock parameters.

Design of an Electromagnetic Energy Harvesting System Applied to Shock Absorber in Sport Utility Vehicle : Part II. Improvement of The Power & Power Density

To harvest the kinetic energy from the vehicle suspension system, a tubular generator, which is composed of a single permanent magnet layer coreless model, was proposed in the previous study. Despite the excessive volume of the generator, both output power and power density are significantly lower than other conventional machines. This paper examines different designs of the tubular generator with the goal to enhance the performance, including a double permanent magnet layers coreless model and a cored model. By using a commercial finite element method (FEM) software, two proposed generators are theoretically analyzed and compared with the conventional generator. Analyzed results reveal that under the same operating conditions, the cored model can regenerate the largest amount of the power density. These results indicate that cored model can be considered as a promising candidate for the application to the electromagnetic shock absorber in sport utility vehicle (SUV).

Modeling and Experiments of a Hydraulic Electromagnetic Energy-Harvesting Shock Absorber

Hydraulic electromagnetic energy-harvesting shock absorbers (HESAs) have been proposed recently, with the purpose to mitigate the vibration of vehicle suspensions and also recover the vibration energy traditionally dissipated by oil dampers. This paper designs an HESA prototype for heavy vehicles and creates a dynamic modeling to study its characteristics. The model shows that the HESA's output force can be decomposed into the electric damping force, friction damping force, the inertia force, and the accumulator force. Based on the modeling, the counteracting effect between the accumulator force and the inertia force is explained, and the influences of the parameters are analyzed. Simulations are conducted to investigate the effects of the high-pressure accumulator and the inertia on the regenerative voltage. Experiments are also carried out to study the characteristics of vibration damping and energy harvesting. Results show that the damping coefficient of the proposed HESA ranges from 32 to 91 kNs/m, which covers most of the damping range of 25–50 kNs/m for typical heavy-duty trucks and 15–80 kNs/m for railway freight vehicles. The average regenerative power reaches 220 W and the corresponding hydraulic efficiency reaches 30%, at a vibration input of 3 Hz frequency and 7 mm amplitude. Moreover, the influences of different hydraulic components on the hydraulic efficiency are also experimentally studied in order to guide the future design of HESAs.

Hybrid electromagnetic shock absorber for energy harvesting in a vehicle suspension

Electromagnetic harvesters need to be designed with a mechanism to amplify the coil relative velocity to ensure compact size and lower weight. This paper discusses a novel technique to use fluid link for velocity amplification in an electromagnetic shock absorber. Incorporation of the fluid amplification significantly improves harvested power, without affecting the system dynamics. Numerical modelling and experimentation of a prototype shock absorber comprising of high energy rare earth magnets have been presented. Peak coil voltage of 0.60–24.2 V was recorded during experimentation on the prototype. Experimental and simulation results validate that incorporation of the fluid amplification link improves the harvested electric power by 9702%. Comprehensive design procedure for better harvesting efficiency and vibration isolation has been discussed. Lastly incorporation of the shock absorber in McPherson strut suspension is illustrated. The real size version will be able to harvest peak power of 18–227 W for the suspension velocities of 0.15–0.4 m/s.

The ride comfort and energy-regenerative characteristics analysis of hydraulic-electricity energy regenerative suspension

For optimization of performances of a hydraulic-electricity energy regenerative suspension (HERS) unit, the tradeoff point was determined based on study of ride comfort and energy-regenerative characteristics of a HERS unit in this study. A HERS unit as a new energy reclaiming suspension device is equipped with an energy-harvesting hydraulic electromagnetic shock absorber (HESA). The HESA together with a quarter car was modeled based on theoretical analysis and experiments, in which the root mean square (RMS) values of the sprung mass vibration acceleration and the recovered power are regarded as the optimization objectives under different road excitation conditions such as the constraints (natural frequency, dynamic displacement, and dynamic load of wheels). The HERS unit was optimized after the relationship between the ride comfort and the energy regeneration was obtained. In comparison with the traditional suspension, the HERS unit may be utilized to improve the ride comfort and meet the vehicle-driving requirements. Moreover, the total input power may be saved by 34-100 W on average while the vibration acceleration is among 0.65-1.06 m/s2. Furthermore, it is verified that the HERS damping force control is the feasible under various load currents.

H∞ Multi-Objective Implementation for Energy Control of Electromagnetic Suspension

In this paper, an electromagnetic shock absorber for passenger car has been designed, fabricated and tested. Multi objective H∞ Controller has been designed and implemented on quarter car test rig. Controllers have been designed to minimize sprung mass acceleration, power requirement and to maximize harvesting energy. Proportional-Integral (PI) Controller with currents input tracking reference has been also implemented for comparisons. Shock absorber has been designed and prototyped to harvest vibration energy and to be controlled by electric current. The shock absorber uses DC permanent magnet motor. Damping force and regenerated current of prototype have been tested on Auto Damping Test Machine (ADFT). The prototype is able to generate 2.59A maximum current with 183.3N damping force when 20 Ω external loads are applied. A DOF mass-spring-damper test rig has been constructed for controller implementation. Simulations have been conducted for verification. With optimal state feedback gain, Kopt = [-514.11 -127.59 -0.00017 -1.14 -0.42 0 0.26], H∞ Multi objective controller is attaining RMS of body acceleration arms= 1.2m/s2, maximum suspension stroke SWSmax= 0.016m, and average power consumption Pcons = 134 Watt. Root Mean Squared Error (RMSE) among experimental and simulations are: 0.31 m/s2, 0.0058m and 2.91 A respectively for body acceleration, suspension travelling and supplied current. With PI controller parameter: Kp = 0.4 and Ki =0.5, feedback gain Cg = 2 and Cs= 0.3, RMS of body acceleration arms= 1.16m/s2, maximum suspension stroke SWSmax = 0.03m, and average power consumption Pcons = 178 Watt. Root Mean Squared Error (RMSE) among experimental and simulations are: 0.85m/s2, 0.0066m and 2.73 A respectively for body acceleration, suspension travelling and supplied current.

Development of an electromagnetic shock absorber

In the present study, an electromagnetic shock-absorber (EMSA) is proposed for a landing structure of a spaceship. The proposed EMSA consists of a copper and steel combined tube, a piston, permanent magnets, and a steel ring. A magnet fixed on the piston is designed to move through the tube when dr iven by an external shock. Shock energy is partially dissipated by an eddy current damping force and a friction force generated from the relative motion of the tube and the magnet. Some of the energy is stored in a magnetic spring consisting of two magnets in which their poles act against each other. To investigate and predict the performance of the proposed EMSA these damping and magnetic forces are simulated and approximated by using an electromagnetic finite element program. Their approximations are verified by experimental results and the numerical model of the proposed EMSA is consequently developed. The proposed EMSA is fabricated and its performance is predicted and verified by the drop test.

Design and analysis of energy-harvesting shock absorber with electromagnetic and fluid damping

The design and numerical simulation of a linear generator for use in an automobile shock absorber are presented in this paper. The conceived linear generator employs high-performance rare earth permanent magnets with compact size to ensure efficient energy recovery. Finite element analysis and Matlab simulation are utilized to derive the generator configurations for the satisfactory utilization of magnets and optimized functioning. Experimentation was performed on a linear generator prototype and electromagnetic shock absorber to validate the numerical analysis. The numerical model is then utilized in the design of a full-scale energy-harvesting shock absorber with fluid damping and a linear generator. A novel feature of the presented work is the use of fluid amplification to simultaneously achieve energy dissipation and velocity amplification. Fluid amplification does not affect the dynamics of the system and increases the coil velocity by approximately eight times. Smooth variation in damping force, improved fail-safe characteristics, and absence of transmission elements, such as mechanical gears, are additional advantages of the system. Matlab Simscape evaluation is employed to analyze comfort, safety, and energy-harvesting characteristics, which are then compared with that of the conventional fluid shock absorber. Simulation with actual road excitation data indicates that the presented system harvests 15 W of the average power from each wheel. Lastly, the layout for integrating the presented shock absorber in McPherson suspension is discussed.