Challenges in Controlling Active Suspensions for High-Speed Off-Road Vehicles

2000 ◽  
Author(s):  
Keyanoush Efatpenah ◽  
Joseph H. Beno ◽  
Steven P. Nichols ◽  
Raul G. Longoria
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Graph Model ◽  
Field Tests ◽  
Active Suspension ◽  
Bond Graph ◽  
Ride Quality ◽  
Road Vehicles ◽  
High Attenuation ◽  
Challenge Control

Abstract The literature includes several useful control approaches for active suspension of off-road vehicles. Some of these approaches rely on preview (look-ahead) of the terrain, while others require knowledge of certain variables that have proven difficult to measure reliably for off-road applications. Sky-hook damping is a widely accepted active suspension control law. Experimental and analytical research with active suspension systems for on- and off-road vehicles have successfully demonstrated substantial improvement in ride quality. The paper begins with a short discussion of a bond graph model of an off-road vehicle equipped with an electromechanical active suspension. The bond graph model facilitated the development of a SIMULINK model used for simulation. Comparison of simulation and experimental results has validated the model, especially for high-frequency terrain inputs. The paper examines how specific examples of off-road conditions challenge control algorithm development. Simulations demonstrate that sky-hook damping (without modification) with gains selected for very high attenuation of high-frequency terrain disturbances do not perform well in response to large displacement, low-frequency inputs and cause suspension bottoming out. By modifying the basic control laws and selecting appropriate controller gains, excellent ride performance was achieved in recent field tests under general terrain conditions.

Design Parameter Sensitivity for a Mountain Bike Rear Shock

2006 ◽  
Author(s):  
Robin C. Redfield
Keyword(s):  
High Speed ◽  
Current Trend ◽  
Graph Model ◽  
Bond Graph ◽  
Design Parameters ◽  
Mountain Biking ◽  
Mountain Bike ◽  
Suspension Systems ◽  
Experimental Response ◽  
And Performance

As the sport of mountain biking matures, equipment continually evolves to afford better biking performance, enjoyment, and safety. In the arena of suspension systems, mountain bikes have moved from rigid suspensions with large, knobby tires to front fork suspensions, and finally full suspensions. Suspensions have gone from elastomeric compliance to air and coil springs with adjustable travel. Damping has progressed from fixed to adjustable rebound, compression, and lockout. The current trend is to add force or frequency dependent damping to minimize response of a suspension from pedal input. A bond graph model of a mountain bike rear shock is developed incorporating adjustable rebound and low-speed compression, high-speed compression, and rider controlled, compression damping initiation. An air shock with a nitrogen charge is modeled with velocity across the shock as input. The dynamic equations that come from the bond graph are simulated to predict key forces, pressures, and flow-rates. Experimental response (forces, displacements, and velocities) of the modeled shock is acquired subject to periodic velocity inputs. The experimental response is used to tune the design parameters of the model and for validation. A sensitivity analysis is then undertaken to determine how significant key design parameters are to the performance of the shock. Once validated, the model is used to better understand the physics and performance of the mountain bike shock and to relate performance to the requirements of expert mountain bikers.

scholarly journals Model of the Floating Bearing Bushing Movement in an External Gear Pump and the Relation to Its Parameterization

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8553
Author(s):  
Miquel Torrent ◽  
Pedro Javier Gamez-Montero ◽  
Esteban Codina
Keyword(s):  
Graph Model ◽  
Field Tests ◽  
Bond Graph ◽  
Gear Pump ◽  
Characteristic Parameters ◽  
Final Model ◽  
Modeling Simulation ◽  
Starting Point ◽  
Loss Coefficients ◽  
External Gear Pump

This article presents the modeling, simulation and experimental validation of the movement of the floating bearing bushing in an external gear pump. As a starting point, a complete pump parameterization was carried out through standard tests, and these parameters were used in a first bond graph model in order to simulate the gear pump behavior. This model was experimentally validated under working conditions in field tests. Then, a sophisticated bond graph model of the movement of the floating bushing was developed from the equations that define its lubrication. Finally, as a result, both models were merged by integrating the dynamics of the floating bushing bearing with the variation of the characteristic parameters (loss coefficients). Finally, the final model was experimentally validated both in laboratory and field tests by assembling the pump in a drilling machine to drive the auxiliary movements. The novelty of this article is the conception and construction of a simple and experimentally validated tool for the study of a gear pump, which relates its macroscopic behavior as a black box (defined by the loss coefficients) to the internal changes of the unit (defined by its internal lubrication).

The Study on Vehicle EHA Active Suspension with Time-Delay Control

2012 ◽  
Vol 178-181 ◽  
pp. 2002-2005
Author(s):  
Fa Rong Kou
Keyword(s):  
Time Delay ◽  
Dynamic Performance ◽  
Graph Model ◽  
Active Suspension ◽  
Hydraulic Cylinder ◽  
Bond Graph ◽  
Control Force ◽  
Time Delay Control ◽  
The Road ◽  
Delay Control

A new vehicle active suspension with Electro-Hydrostatic Actuator (EHA) is suggested. The system consists of two parts: spring and actuator with variable control force. The actuator includes hydraulic cylinder, hydraulic pump, controller, etc. According to bond graph principle, bond graph model of EHA active suspension are built. For vehicle active suspension system, unavoidable time delay may appear in the controllable course. Time-delay influence on the dynamic performance of vehicle active suspension is analyzed. Physical prototype and experimental rig for EHA active suspension is built. Then the tests of suspension prototype with time-delay control are carried out on the developed test rig. The results show that the sprung mass acceleration of the active suspension with time-delay compensation significantly declines by 11.56% under the road input of 1.1Hz and by 12.8% under the road input of 1.5Hz

H∞ Vibration Control of Active Suspension for High-Speed Train

1995 ◽  
Vol 7 (4) ◽  
pp. 319-323
Author(s):  
Akihiko Shimura ◽  
◽  
Kazuo Yoshida
Keyword(s):  
Vibration Control ◽  
High Speed ◽  
Synthesis Method ◽  
Active Suspension ◽  
The Body ◽  
Dynamical Analysis ◽  
Control Synthesis ◽  
Ride Quality ◽  
High Speed Train ◽  
Hydraulic Actuator

In this paper, H∞ control theory and <I>μ</I> synthesis are applied to vibration control of active suspension for high speed train. A linear 58th order model is built for the dynamical analysis of the train model. This model takes into account the body, truck frame, wheel, hydraulic actuator, and property of track irregularity. A hydraulic actuator replaces a lateral damper between body and truck frame of the conventional passive suspension train. The controller for vibration control is synthesized by H∞ control synthesis and improved by <I>μ</I> synthesis. The characteristics and performances of the controllers are examined by performing numerical calculations of frequency response and computational simulations. As a result, it is clarified that the active suspension for highspeed train is effective to improve ride quality and that the present synthesis method is useful.

Design and Development of Smart Semi Active Suspension for Nonlinear Rail Vehicle Vibration Reduction

2020 ◽  
Vol 20 (11) ◽  
pp. 2050120
Author(s):  
Sunil Kumar Sharma ◽  
Jaesun Lee
Keyword(s):  
Predictive Model ◽  
High Speed ◽  
Mr Damper ◽  
Active Suspension ◽  
Creep Model ◽  
Ride Quality ◽  
High Speed Rail ◽  
Running Safety ◽  
Rail Vehicle ◽  
Fluid Dampers

In this paper, the semi-active suspension in railway vehicles based on the controlled magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety and ride quality for a high-speed rail vehicle. Predictive model controllers are used as system controllers to determine the desired damping forces for front and rear bogie frame with force track-ability. A 28 degree of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The MR model of Ali and Ramaswamy is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper, i.e. passive, semi-active low, semi-active high and semi-active smart controller based on predictive model controller. A comparison indicates that the semi-active controller gives the optimum for comfort vibration actuation and improves the ride quality and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

The Simulation and Experimental Study on a Novel Vehicle Active Suspension with Electro-Hydrostatic Actuator

2012 ◽  
Vol 430-432 ◽  
pp. 1984-1987
Author(s):  
Fa Rong Kou ◽  
Jian Ma ◽  
Ji Bai Wang
Keyword(s):  
Fuzzy Control ◽  
Fuzzy Logic Controller ◽  
Ride Comfort ◽  
Graph Model ◽  
Active Suspension ◽  
Hydraulic Cylinder ◽  
Bond Graph ◽  
Suspension System ◽  
Control Force ◽  
Passive Suspension

Actuator is a very important part of vehicle active control suspension. Based on the analyses of traditional passive suspension and active suspension system, a novel vehicle active suspension with Electro-Hydrostatic Actuator (EHA) is put forward. The system consists of two parts: spring and actuator with variable control force. The actuator includes hydraulic cylinder, hydraulic pump, controller, etc. According to bond graph principle, bond graph model of EHA active suspension are built. In addition, sky-hook controller and fuzzy logic controller are designed and sky-hook control and fuzzy control active suspension are simulated using MATLAB tools. The prototype and test rig of EHA active suspension are developed and bench tests are carried out. The simulation and experimental results show that sky-hook control and fuzzy control active suspension with EHA provide better ride comfort and stability than passive suspension system.

The Control Study of Vehicle Active Suspension with Electro-Hydrostatic Actuator

2011 ◽  
Vol 97-98 ◽  
pp. 716-720 ◽  
Author(s):  
Fa Rong Kou
Keyword(s):  
Fuzzy Control ◽  
Fuzzy Logic Controller ◽  
Ride Comfort ◽  
Graph Model ◽  
Active Suspension ◽  
Hydraulic Cylinder ◽  
Bond Graph ◽  
Control Force ◽  
Passive Suspension ◽  
System A

Actuator is the key to vehicle active suspension. Based on the analyses of traditional passive suspension and active suspension system, a novel vehicle active suspension with Electro-Hydrostatic Actuator (EHA) is put forward. The system consists of two parts: spring and actuator with variable control force. The actuator is made up of hydraulic cylinder, hydraulic pump, controller and BLDCM. According to bond graph principles, bond graph model of 2 DOF passive suspensions and bond graph model of EHA active suspension are built. Moreover, fuzzy logic controller is designed and fuzzy control active suspension is simulated using MATLAB tools. The prototype and test rig of EHA active suspension are developed and bench tests are carried out. The simulation and experimental results show that fuzzy control active suspension with EHA provides better ride comfort, handling and stability than passive suspension.

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