Improve Vehicle Dynamics Research Articles

Improving vehicle dynamics employing individual and coordinated sliding mode control in vehicle stability, active front wheel steering and active rear wheel steering systems in co-simulation environment

The goal for the future, safer and more sustainable transportation leads to implementation of many advanced systems in vehicles. In this paper, a vehicle model with stability control system that uses the braking system is regarded as a base active vehicle. Two alternative vehicle models are considered where this system is combined and integrated with active front wheel steering (AFS) and active rear wheel steering (ARS) system, separately. For the purpose of this research, 3D virtual vehicle models based on a B-segment vehicle were created in ADAMS/Car. As a research tool, a co-simulation approach between ADAMS/Car and MATLAB/Simulink was used. Several sliding mode controllers (SMC) have been proposed and implemented in MATLAB/Simulink in order to analyse the potential improvements of the vehicle dynamics due to the integration and coordination of these systems. In the same MATLAB/Simulink environment, a reference 2DOF nonlinear bicycle model was used. The vehicle models were simulated in driving scenarios based on standardized ISO 7401 test procedures. The scenarios include situations where the passive vehicle loses its stability or fails to complete the manoeuvre while the vehicles with stability control or integrated control systems successfully complete it.

Risk-Sensitive Rear-Wheel Steering Control Method Based on the Risk Potential Field

Various driving assistance systems have been developed to reduce the number of automobile accidents. However, the control laws of these assistance systems differ based on each situation, and the discontinuous control command value may be input instantaneously. Therefore, a seamless and unified control law for driving assistance systems that can be used in multiple situations is necessary to realize more versatile autonomous driving. Although studies have been conducted on four-wheel steering that steers the rear wheels, these studies considered the role of the rear wheels only to improve vehicle dynamics and not to contribute to autonomous driving. Therefore, in this study, we define the risk potential field as a uniform control law and propose a rear-wheel steering control system that actively steers the rear wheels to contribute to autonomous driving, depending on the level of the perceived risk in the driving situation. The effectiveness of the proposed method is verified by a double lane change test, which is performed assuming emergency avoidance in simulations, and subject experiments using a driving simulator. The results indicate that actively steering the rear wheels ensures a safer and smoother drive while simultaneously improving the emergency avoidance performance.

Step-control and vibration characteristics of a hybrid vehicle suspension system considering energy consumption

This paper proposes a hybrid suspension system, consisting of a linear electric motor (LM) and a semi-active mono-tubed magnetorheological damper (MRFD), to improve vehicle dynamics with lower power demand. For determining the damping force directly and concisely, a modified bi-viscosity magnetorheological fluid (MRF) model that explicitly includes the current parameter is developed. The fabricated LM and MRFD are calibrated and tested for validation of the implemented mathematical models. The simulation results show that the modified bi-viscosity model is able to calculate the experimental MRFD external forces very well. Thereafter, the hybrid suspension system is integrated into a 2-DOF (degree-of-freedom) quarter-vehicle dynamic model for simulation analysis, considering bump and pothole road profiles and the wheel bounce movements. Moreover, the two step-control methods, namely SC1 and SC2, are modelled for enhancing vibration mitigation and reducing power demand. The MRFD current influences on the root mean square (RMS) of the vehicle body vibration amplitudes are studied. Results reveal that the optimal MRFD current is ranged from 1 to 2.2A considering the SC1 method. Finally, the energy efficiency of the step-control methods is proved to be much higher than the PID method especially at low vehicle speed and in large road heave situations.

Effect of truck shear pads on the dynamic behaviour of heavy haul railway cars

Shear pads are devices used to improve vehicle dynamics performance on heavy haul railways wagons. In this work, we present a method to determine the elastic properties of such components using experimental/numerical approach. The final goal is to provide adequate input to multi-body analysis software commonly applied to study and design railroad vehicles. We also considered the effect of side frame compliance to primary suspension performance, a influence that is often neglected on this type of study. Our results show that the application of shear pads can indeed promote a significant reduction of wheel and rail wear by decreasing the total frictional energy . We also show that, under the simulated conditions, the most important stiffness coefficient to wear is the longitudinal one.

Improved Vehicle Dynamics with Development in Suspension Geometry

Improved Vehicle Dynamics with Development in Suspension Geometry

Intelligent optimal controller design applied to quarter car model based on non-asymptotic observer for improved vehicle dynamics

A novel active suspension control strategy is introduced to improve dynamic response of vehicle suspension systems. The proposed algorithm is a fusion of classical controller design methods together with an online observer and is based on the cancelation of system disturbances. The operational calculus method and the differential algebraic theory are applied to build the observer/compensator that is appended to the classical linear quadratic regulator. An ultra-local model based on linear algebraic rules is presented avoiding the use of a precise mathematical model while guaranteeing the stability of the overall system. Simplicity of implementation, low power demand and significant enhancement of active suspension performance are the observed features of the proposed controller. The numerical simulations illustrate the effectiveness and the robustness against sprung mass variation of the proposed control method compared to proportional–integral–derivative controller, intelligent proportional–derivative controller, linear quadratic regulator and active disturbance rejection—linear quadratic regulator.

Ride comfort control of in-wheel motor drive unmanned ground vehicles with energy regeneration

Adopting in-wheel motor drive can improve vehicle dynamics control functions, which is the most ideal drive mode of unmanned ground vehicle. However, with the increase of the heavy unspring-mass vibration energy while the vehicle running on uneven road, the ride comfort will be seriously deteriorated. To solve the problem and save energy, the ride comfort control based on regenerative suspensions is adopted. By analyzing the vibration performance, the adverse effects of the vehicle equipped in-wheel motors with passive suspensions are revealed. Then, the dynamics model of the regenerative suspension is built. Based on the suspension power recovery, the multi-state optimal control strategy for improving the ride comfort is designed. Finally, comparing the simulation results of regenerative suspensions with the test results of passive suspensions, when the vehicle mass ratio decreases from 8:1 to 4:1, the body acceleration and the root mean square value of tire dynamic load increase by 28.1% and 31.6%, correspondingly. With the control method, the body acceleration is decreased by 23% and reaches the level of conventional vehicles. Furthermore, part of the vehicle vibration energy can be recovered and the vehicle driving range can be extended.

Identification of Road-Surface Type Using Deep Neural Networks for Friction Coefficient Estimation.

Nowadays, vehicles have advanced driver-assistance systems which help to improve vehicle safety and save the lives of drivers, passengers and pedestrians. Identification of the road-surface type and condition in real time using a video image sensor, can increase the effectiveness of such systems significantly, especially when adapting it for braking and stability-related solutions. This paper contributes to the development of the new efficient engineering solution aimed at improving vehicle dynamics control via the anti-lock braking system (ABS) by estimating friction coefficient using video data. The experimental research on three different road surface types in dry and wet conditions has been carried out and braking performance was established with a car mathematical model (MM). Testing of a deep neural networks (DNN)-based road-surface and conditions classification algorithm revealed that this is the most promising approach for this task. The research has shown that the proposed solution increases the performance of ABS with a rule-based control strategy.

IMPLEMENTATION OF ADVANCED CONTROL METHODS FOR IMPROVED VEHICLE DYNAMICS AND SAFETY USING CO-SIMULATION APPROACH

The increasing application of mechatronic devices in everyday life increases the demands for higher reliability and safety in order to achieve more sustainable systems. Inspired by the enormous efforts put in decreasing the number of accidents on the roads which is attributed to implementation of improved mechatronic systems, a controller for improved vehicle dynamics was created and comparison between two advanced control methods was made. Improved vehicle dynamics and stability control system is mandatory for most vehicles, and in order to make contribution in this field, a cascade controller for selective wheel braking control is implemented in a virtual 3D vehicle model. By using sliding mode control (SMC) and Linear Quadratic Regulator (LQR) as adopted control methods, an improved vehicles dynamics is achieved and also a more reliable system is created due to the adaptiveness of the control strategies. Using co-simulation approach involving ADAMS/Car and Matlab/Simulink, results for standardized vehicle maneuvers are obtained and the benefits of the proposed controllers are analyzed.

An Analytical Approach to Improve Vehicle Maneuverability via Torque Vectoring Control: Theoretical Study and Experimental Validation

To improve the maneuverability of a vehicle and fully leverage the advantages of torque vectoring control (TVC) in improving vehicle dynamics, a method to analytically improve the cornering response based on TVC is proposed in this paper. A feedforward and feedback control architecture based on a two-degree-of-freedom vehicle model is first introduced. An analytical expression of the yaw moment feedforward model is derived under the condition that the transfer function of the ideal yaw rate with respect to the real one is equal to 1. Then, the key influencing factors of the additional yaw moment are investigated in detail. More importantly, the real experimental results under steady and transit state are analyzed to demonstrate how the proposed controller can improve vehicle maneuverability. Experimental results show that the bandwidth of vehicle transient response could be improved by 29.6% in the tests. The controller can be easily extended to any type of TVC even though it is applied to a rear-wheel driven electric vehicle in this paper.

Feasibility Study of an Innovative Urban Electric-Hybrid Microcar

This paper presents the feasibility study of a new platform for electric-hybrid quadricycles, developed by addressing important concepts like passive safety and comfort, which often represent a shortcoming in this vehicle category. Starting from packaging of energy storage system and macroscopic subsystems as the main technological constraint, the study has been entirely developed in a virtual environment, with finite element verifications on preliminary models, and a subsequent cooperation phase between computer aided design and finite element analysis softwares, with a guideline for the main tests being that each could feasibly be carried out on a complete vehicle model in order to validate the original assumptions. The resulting design, with a body curb mass of less than 100 kg, was capable of integrating optimal static stiffness characteristics and crash performance, together with improved vehicle dynamics thanks to an innovative suspension archetype.

Car body and bogie connection modification for track curves passability improvement

For Tram cars, it is often necessary to operate in cities on strongly curved track, which is followed by an increased effect of the vehicle on the track. Especially, this increased effect occurs in spiral transition curves situated between direct and arc sections or between two arc sections of different radius. In such case, increased guiding forces, creep in the rail - wheel contact, wear and noise generation can be observed. Exactly with the aim to reduce these undesirable effects we designed a tram bogie with steered wheelsets. This paper deals with a modification of its coupling to vehicle body in order to improve vehicle dynamics in transition curves. Proposed innovative construction of this coupling unit is registered by authors under Utility Model Nr. u201609015 and Utility Model Nr. u201703246. Description of the proposed way for a vehicle to pass through curved track with regard to bogie-body coupling and wheelset steering mechanisms with usage of multibody computing software is given in this paper.

Vehicle Stability Enhancement through Hierarchical Control for a Four-Wheel-Independently-Actuated Electric Vehicle

In this paper, an optimal control strategy for a four-wheel-independently-actuated electric vehicle (FWIA EV) is proposed to improve vehicle dynamics stability and handling performance. The proposed scheme has a hierarchical structure composed of an upper and a lower controller. The desired longitudinal and lateral forces and yaw moment are determined based on the sliding-mode control (SMC) scheme in the upper controller, which takes the longitudinal and lateral velocity and the yaw rate as control variables. In the lower controller, an optimization algorithm is adopted to allocate the driving/braking torques to each in-wheel motor. A cost function with adjustable weight coefficients is specially designed by taking the motor power capability and the tire workload into consideration. The simulation and hardware-in-loop experimental results show that the proposed control strategy exhibits superior performance in comparison to commonly-used rule-based control strategies, and has the capability of online implementation.

A semi-active suspension control algorithm for vehicle comprehensive vertical dynamics performance

ABSTRACTComprehensive performance of the vehicle, including ride qualities and road-holding, is essentially of great value in practice. Many up-to-date semi-active control algorithms improve vehicle dynamics performance effectively. However, it is hard to improve comprehensive performance for the conflict between ride qualities and road-holding around the second-order resonance. Hence, a new control algorithm is proposed to achieve a good trade-off between ride qualities and road-holding. In this paper, the properties of the invariant points are analysed, which gives an insight into the performance conflicting around the second-order resonance. Based on it, a new control algorithm is proposed. The algorithm employs a novel frequency selector to balance suspension ride and handling performance by adopting a medium damping around the second-order resonance. The results of this study show that the proposed control algorithm could improve the performance of ride qualities and suspension working space up to 18.3% and 8.2%, respectively, with little loss of road-holding compared to the passive suspension. Consequently, the comprehensive performance can be improved by 6.6%. Hence, the proposed algorithm is of great potential to be implemented in practice.

Effect of the electromagnetic force on the power-train vibration of the in-wheel motor driving system with rubber bushings

For an in-wheel motor driving system with rubber bushings, the driving motor is integrated into the wheel. A magnet gap deformation of the motor will be inevitably caused by the road excitation, which will produce an unbalanced electromagnetic force and influence the power-train vibration. Furthermore, the rim is flexibly connected to the motor rotor by rubber bushings, and a strong coupling and nonlinear vibration of the power-train in all directions can be demonstrated under the electromagnetic excitations. Thus, a 14-degree-of-freedom coupling vibration model of the power-train is first developed for the in-wheel motor driving system with rubber bushings, including the bushing and bearing models. Then, the mathematical model is deduced using a Lagrangian approach. Finally, based on the model, a coupling vibration analysis is conducted under different electromagnetic force excitations. The results indicate that there are coupling vibration components in the torsional direction, except the one-time rotating frequency; however, in the bending direction, the vibration response includes a one-time rotating frequency component and an excitation frequency component of the electromagnetic force. Furthermore, the results indicate that the bushing plays an important role in reducing the power-train vibration, which has a positive effect on the improving vehicle dynamics.

Integrated model-based approach for the optimisation of vehicle ride comfort and handling characteristics: integrated vehicle dynamics model design

Recently, the research work for the improvement of the ride comfort quality and dynamic characteristics for vehicle handling performance is taking increasing attention. Although much work has been done on numerical and experimental studies to improve the ride quality and dynamic characteristics, many applications face limitations with respect to conflict between ride comfort and vehicle handling, which mostly depend on the suspension characteristics. This research presents an integrated model-based approach to design optimised suspension systems to improve vehicle dynamics behaviour and to eliminate the drawbacks of physical testing and reduce the cost. This paper is about the part of an ongoing research on vehicle ride comfort and handling optimisation, and integrated full vehicle model design and model validation studies are given in this paper. The optimisation model will be presented in another paper to choose a compromise solution between ride comfort and handling performance.

Development of a 20-Pole–24-Slot SPMSM With Consequent Pole Rotor for In-Wheel Direct Drive

In-wheel motors bring a fundamental change in electric vehicle technology by removing conventional mechanical components and freeing up space inside the vehicle body. This approach ultimately helps to realize all-wheel independent control for improved vehicle dynamics and increased vehicle design freedom. However, when space allowed for an in-wheel motor is taken into consideration, high torque density, high efficiency, and wide-speed-range capability are typically required. This paper specifically investigates a 20-pole–24-slot surface permanent magnet synchronous motor with consequent pole rotor for in-wheel direct drive since this topology is well suited for high-pole motors and thus high-torque direct-drive applications. Extensive finite-element analysis is carried out to characterize the proposed motor, and the practical feasibility of the proposed motor is discussed. Finally, the validity of the analysis was experimentally verified.

Surface Tension and Contact Angle Analysis with Design of Propellant Measurement Apparatus

Propellant management devices located within the propellant tanks of spacecraft and satellites operating in microgravity environment are used to control propellant distribution within the tank to improve vehicle dynamics and performance. In the microgravity environment, viscous and capillary forces can dominate body forces, and special considerations of these effects must be taken into account when designing a unique propellant management device for each mission and propellant combination. New high-performance green propellants are under development to improve performance and reduced mission costs, and to elicit efforts to further improve design of fuel-tailored propellant storage and feed systems. This paper presents the design and implementation of apparatuses intended to obtain high-quality imagery of liquids in exotic environments consistent with propellant tanks for rockets and spacecraft, as well as a review and comparison of several droplet photograph analyzing techniques used to determine surface tension and wall contact angle. This paper’s review of testing and analysis techniques, as well as its development of a testing apparatus that can sustain an adequately pressurized environment for cryogenic gases in addition to chemical compatibility for solvent-based propellants, can be used to design spacecraft or satellite propellant management devices that operate with newly emerging propellants.

Life cycle assessment of automotive lightweighting through polymers under US boundary conditions

In the transportation sector, reducing vehicle weight is a cornerstone strategy to improve the fuel economy and energy efficiency of road vehicles. This study investigated the environmental implications of lightweighting two automotive parts (Ford Taurus front end bolster, Chevrolet Trailblazer/GMC Envoy assist step) using glass-fiber reinforced polymers (GFRP) instead of steel alloys. The cradle-to-grave life cycle assessments (LCAs) for these studies consider a total service life of 150,000 miles for two applications: a 46 % lighter GFRP bolster on the 2010 Ford Taurus that replaced the 2008 steel and GFRP bolster, and a 51 % lighter GFRP running board for the 2007 Chevrolet Trailblazer/GMC Envoy that replaced the previous steel running board including its polymer fasteners. The life cycle stages in these critically reviewed and ISO-compliant LCA studies include the production of upstream materials and energy, product manufacturing, use, and the end-of-life treatment for all materials throughout the life cycle. The results show that the lighter GFRP products performed better than the steel products for global warming potential and primary energy demand for both case studies. In addition, the GFRP bolster performed better for acidification potential. The savings of fuel combustion and production during the use stage of a vehicle far outweigh the environmental impacts of manufacturing or end-of-life. An even greater benefit would be possible if the total weight reduction in the vehicle would be high enough to allow for the reduction of engine displacement or an elongation of gear ratio while maintaining constant vehicle dynamics. These so-called secondary measures allow the fuel savings per unit of mass to be more than doubled and are able to offset the slightly higher acidification potential of the GFRP running board which occurs when only the mass-induced fuel savings are considered. The lightweight GFRP components are shown to outperform their steel counterparts over the full life cycle mainly due to the reduced fuel consumption of the vehicle in the use phase. To harvest the benefits of light weighting to their full extent, it is recommended that the sum of all mass reductions in the design process be monitored and, whenever feasible, invested into fuel economy by adapting the drive train while maintaining constant vehicle performance rather than leveraging the weight reduction to improve vehicle dynamics.

Investigation of influence of constraints with radius links on locomotive axle load distribution and wheelset steering ability

The problem of improving the tractive and dynamic performance of locomotives by means of using axle boxes with inclined radius links was investigated. The kinematics of axle boxes with different variants (different angles) and designs of inclined radius links, based on the vector contour method for link mechanisms, was studied. The results of a bogie design with vertically inclined radius links were used for the improvement of vertical load distribution for locomotives. The behavior of a locomotive running in a curve is more complicated because the lateral forces appear between a flange of the wheel and the head of the rail in the contact zone, and the values of wheel slip are higher than for straight sections of track. These two factors are the main reasons for wheel wear. Theoretical and experimental investigations to reduce wear and to improve vehicle dynamics were made, and the results obtained show that an effective solution can be reached by the use of inclined links to the longitudinal axis of a bogie in the horizontal plane. Questions about the development of a bogie with a radial installation and active steering are discussed.