Browse Topic: Electromagnetic suspension

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Crank-Lever Electromagnetic Damper (CLEMD) Design for Automobile Suspension System06-13-01-00022/4/2020
An effective damper is among the most important components of the suspension system. It ensures the right amount of damping force is acting on the suspension system to provide comfort to the passengers and proper road holding to tires. Unfortunately, the energy absorbed by the dampers from the suspension system gets wasted in the form of heat. In this article, it is proposed to use innovative electromagnetic damper (EMD) with a crank-lever mechanism to recover energy from the suspension system. The goal is to develop a lightweight design of EMD that can recover a high amount of power. For the design, an off-road vehicle is used since in off-road vehicles the amount of power wasted in the suspension system is high. Three different design approaches are used, which include single-stage gearbox type, two-stage gearbox type, and three-stage gearbox type of CLEMD. Out of them, the best design, i.e. three-stage gearbox type of CLEMD is selected because of minimum weight and inertia of the components. This article is focused on the design and analysis of the three-stage gearbox type of CLEMD. On the basis of the output of numerical simulations of vehicle model, specifications for crank-lever electromagnetic damper (CLEMD) are driven and design is carried out. Also, performance analyses of CLEMD are carried out by interfacing model of CLEMD with the model of a vehicle. The advantage of CLEMD is it can act as an actuator to provide active force in an active suspension system.
Todmal, Prashant Eknath, Melzi, Stefano
Attitude Control of the Vehicle with Six In-Wheel Drive and Adaptive Hydro Pneumatic Suspensions2019-01-04564/2/2019
The ability of actively adjusting attitude provides a great advantage for those vehicles used in special environments such as off-road environment with extreme terrains and obstacles. It can improve vehicles’ stability and performance. This paper proposes an attitude control system for realizing the active attitude adjustment and vehicle motion control in the same time. The study is based on a vehicle with six wheel independent drive and six independent suspensions (6WIDIS), which is a kind of unmanned vehicle with six in-wheel drives and six independent hydro pneumatic suspensions. With the hydro- pneumatic suspensions, the vehicle’s attitude can be actively adjusted. This paper develops a centralized- distributed control strategy with attitude information obtained by multi-sensor fusion, which can coordinate the complex relationship among the six wheels and suspensions. The attitude control system consists of three parts. The first part is the attitude determination that includes attitude sensors and a method to measure any quantity sensitive to attitude and determine the real-time vehicle status. The second part is the attitude adjustment that computes the input torques to follow the desired roll and pitch angles. The third part is an attitude actuator that determines a desired force for each hydro pneumatic suspension. In order to simulate the practical vehicle more realistically, a dynamic model with 18 degrees of freedom is established. A torque vector controller is also developed to provide the excellent steering ability, skid-resistance and robustness for the 6WIDIS, which is the basis of the attitude control. Simulation tests are conducted to evaluate the performance of the proposed attitude control system. The simulation results show that the performance of the proposed attitude control system is good and it can improve the obstacle performance, mobility and flexibility of the vehicles.
Li, Boxin, Zheng, Gangtie, Wang, Zhaokui
Design and Control of a Novel Geared Electromagnetic Active Suspension2016-01-15544/5/2016
A novel geared electromagnetic active suspension is proposed in this paper. A pushing rod and a rocker are introduced to transfer the suspension vertical motion to the rotational motion of the motor. Comparing with the common ball-screw active suspension, it presents advantages of simple structure, easy manufacturing and module design. As the state variables of the suspension system cannot be all obtained for the sake of cost, taking the suspension deflection as the measurement, an output feedback LQR optimal controller is adopted, and it is concluded that the system can be stable with damping. Considering the nonlinearity of equivalent stiffness and unsprung mass caused by the system structure, parameter perturbation ranges are concluded through dynamic analysis, and robust H∞ control algorithm is proposed to realize the multi-objective optimization. The performance comparisons of both controllers mentioned above are carried out in the ADAMS/MATLAB co-simulation to reflect the influence of the nonlinearity of real time in practice. The results conclude that, in real system containing nonlinearity and parameter perturbations, the robust H∞ controller performs better in robustness of improving the ride comfort and handling stability.
Gu, Cheng, Chen, Xinbo, Yin, Jun
Design, Fabrication and Testing of a Regenerative Strut2014-01-19384/1/2014
The fuel prices are increasing every day and so are the pollution caused by vehicles using fossil fuels. Moreover, in a car with an internal combustion engine, we get on average 25% efficiency, the other 75% is wasted, mostly through friction and heat. One important loss is the dissipation of vibration energy by shock absorbers in the vehicle suspension under the excitation of road irregularity and vehicle acceleration or deceleration. In this paper we design, manufacture and test a regenerative coil-over strut that is compact, simple in design and more economical. Since our strut is a modification of an existing strut design, it would be much more feasible to implement. We tested our prototype strut using a TATA Indica car under city road conditions. The damping characteristics and output voltage of the strut were recorded and compared with a normal coil over strut. Based on the test data, it was found that the strut was able to recover about 8-10 watts of electricity at 20kmph.
Nandakumar, Pragadish
Assessment of Vehicle Performances with Energy-Harvesting Shock Absorbers2013-01-01704/8/2013
Energy-harvesting from vehicle suspensions has attracted a lot of attention recently due to its potential to recover large amount of kinetic energy which is traditionally wasted in oil shock absorbers, besides it can improve the ride comfort and road handling at the same time. Rotary electromagnetic mechanism has been a popular solution in the design of energy-harvesting shock absorbers and recently an innovative energy-harvesting shock absorber based on so-called mechanical motion rectifier (MMR) has been proposed, which converts the irregular bi-directional suspension vibration into unidirectional motion of the generator. Though it may offer advantages of higher mechanical reliability and harvesting efficiency, its influence on the whole vehicle dynamics is not known yet due to the nonlinearity of the MMR shock absorber. This paper presents an integrated model of a quarter car with a conventional or MMR-based rotary electromagnetic energy-harvesting shock absorber, and assesses the vehicle dynamics and energy-harvesting potential under various road conditions.
Li, Peng, Zuo, Lei
Energy Dissipation and Recovery of Vehicle Shock Absorbers2012-01-20379/24/2012
This paper presented a brief derivation of the energy dissipation by vehicle shock absorbers. Analysis between energy dissipation and damping coefficient, the road displacement power spectral density, the vehicle speed and the tire stiffness was carried out. Then an energy recovery scheme was put forward, and the bench test proved that the energy harvest scheme is feasible. In the end, this paper provided detailed derivation of the characteristics of the hydraulic electromagnetic energy-regenerative shock absorber, which increases its feasibility and practicability.
Fang, Zhigang, Guo, Xuexun, Xu, Lin
Dual Purpose Fuzzy Logic Controller for an Active Suspension System2002-01-09863/4/2002
The use of a fuzzy logic controller for an active suspension system on a wheeled vehicle is investigated. Addressing the opposing goals of ride quality and bump stop avoidance are integrated into one control algorithm. Construction of the fuzzy rules base will be discussed comprehensively along with the membership function setup for both the input and output variables. Numerous quarter-car simulation comparisons will be performed of the fuzzy controller versus the standard skyhook damper controller. The comparisons will include a variety of terrain inputs. Laboratory testing of the fuzzy controller on a single wheel station system is also included.
Mock, J. R., Weeks, D. A., Beno, J. H., Nichols, S. P., Bresie, D. A., Guenin, A. M.
Robust Analysis of Vehicle Suspension System Uncertainty2001-01-15824/30/2001
The paper presents the systematic approaches toward robust stability analysis of H2/H∞ controlled active suspension systems. The computational algorithms for the structured singular value μ are the main features of the work with an emphasis on quantifying the effects of uncertainty of the systems. The representation of vehicle parameter uncertainties is given in detail. The robustness test is subsequently done based on a quarter vehicle model. The results have showed that the H∞ controller is the best one on both robust stability and robust performance.
Ma, Fangwu, Hibberd, Roger, Men, Yongxin
Laboratory Testing of Active Electromagnetic Near Constant Force Suspension (NCFS) Concept on Subscale Four Corner, Full Vehicle Test-Rig9710882/24/1997
In March of 1995, the University of Texas at Austin Center for Electromechanics (UT-CEM) began work on developing active suspension control algorithms for four-wheeled, off-road, rough terrain, vehicles. To serve as a test platform to validate simulations, a four corner test-rig, representing a military HMMWV at one third scale, was designed and fabricated. Multiwheel control algorithms were developed, based on single wheel concepts previously described in SAE publications. The four-wheel test-rig performance compared well with single wheel test-rig performance, showing that the active suspension concepts developed by UT-CEM, which do not require advanced terrain knowledge (i.e., no “look-ahead”), are compatible with full vehicle control.
Weeks, D. A., Beno, J. H., Bresie, D. A., Guenin, A. M.
Superconducting Maglev and its Electromagnetic Characteristics9519228/1/1995
A new test line of superconducting maglev is under construction, reflecting the results of Miyazaki test line. The null flux levitation system arranging 8-figured levitation coils on the sidewall is installed about 2km long in the middle part of the 7km guideway. The characteristics of the levitation, guidance and propulsion system have been tested with the test vehicle MLU002N. The results agreed well with analytical ones. As levitation and guidance forces were larger than those of normal flux system, lower take-off speed was attained on this section. The new test line of 42.8km long adopts this null flux system, implementing those results. Vehicle and coils to be tested on the new test line are summarized as far as they are related to electromagnetic characteristics are concerned.
Fujiwara, Shunsuke
The Transrapid Maglev System - An Update9215838/1/1992
This paper presents the status of the Transrapid Maglev System and the first commercial super-speed maglev application in the world planned for Orlando, Florida. It includes a brief summary of SAE paper No. 89 1714 which was presented in August 1989 and covers subsequent developments. It also includes some discussion of institutional factors to be considered when planning the implementation of a new system. The purpose of this paper is to provide an update on the status of the 500 km/hr super-speed magnetically levitated ground transportation system that was developed in Germany. This maglev system features contactless electromagnetic suspension and long stator three-phase propulsion. This transportation mode has little effect on the environment, is safe and cost effective.
Dickhart, William W.
The Transrapid Maglev System8917148/1/1989
A 300 mph (500km/hr) magnetically levitated ground transportation system, developed in Germany, is now ready for revenue application. The Maglev system features contactless electromagnetic suspension and long stator three-phase propulsion. This transportation mode has little effect on the environment, is safe, and is cost effective. A revenue system is planned in Germany and a proposal for a system in Florida is under consideration.
Dickhart, William W.
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