Narrow Vehicle Research Articles

Dynamic Modeling and Control of a 4-Wheel Narrow Tilting Vehicle

The automotive industries currently face challenges such as emission limits, traffic congestion, and limited parking, which have prompted shifts in consumer preferences and modern passenger vehicle requirements towards compact vehicles. However, given the inherent limited width of compact vehicles, the potential risk of vehicle rollover is greater than that of regular vehicles. This paper addresses the safety concerns associated with vehicle rollover, focusing on narrow tilting vehicles (NTVs). Quantifying stability involves numerical indicators such as the lateral load transfer ratio (LTR). Additionally, a unique approach is taken by applying ZMP (zero moment point), commonly used in the robotics field, as an indicator of vehicle stability. Effective roll control requires a detailed analysis of the vehicle’s characteristic model and the derivation of lateral and roll dynamics. The paper presents the detailed roll dynamics of an NTV with a MacPherson strut-type suspension. A stability-enhancing method is proposed using a cascade structure based on the internal robust position controller and outer roll stability controller, addressing challenges posed by disturbances. Experimental verification using Simscape Multibody and CarSim validates the dynamic model and controller’s effectiveness, ensuring the reliability of the proposed tilting control for NTVs in practical scenarios.

Narrow Tilting Vehicle Drifting Robust Control

The narrow tilting vehicle receives extensive public attention because of traffic congestion and environmental pollution, and the active rolling motion control is a traffic safety precaution that reduces the rollover risk caused by the structure size of the narrow vehicle. The drifting motion control reflects the relatively updated attentive research of the regular-size vehicle, which can take full advantage of the vehicle’s dynamic performance and improve driving safety, especially when tires reach their limits. The narrow tilting vehicle drifting control is worthy of research to improve the driving safety of the narrow tilting vehicle, especially when tires reach the limit. The nonlinear narrow tilting vehicle dynamic model is established with the UniTire model to describe the vehicle motion characteristics and is simplified to reduce the computation of the drifting controller design. The narrow tilting vehicle drifting controller is designed based on the robust theory with uncertain external disturbances. The controller has a wide application, validity, and robustness and whose performance is verified by realizing different drifting motions with different initial driving motions. The narrow tilting vehicle drifting robust control has some practical and theoretical significance for more research.

Research on steering-tilting characteristics of an active tilting three-wheeled vehicle

Active tilting narrow vehicles can prevent rollover and improve riding stability through active tilting technology during steering, but it is difficult to obtain the turning radius and solve the optimal tilting angle. In this paper, based on the active tilting three-wheeled vehicle (ATTWV), the geometric analysis method of steering wheel’s alignment was proposed and used to calculate the specific formula of turning radius during steering and tilting, and the effect of tilting on the turning radius was studied. Based on the steering and tilting mathematical model of force equilibrium state, the ideal tilting angle was solved and the S-shaped curve steering test verification was carried out with the prototype vehicle. The results show that the lateral acceleration of the vehicle fluctuates within ±0.16 g during steering, realizing the equilibrium between the component of gravity and centrifugal force. The average error between the actual tilting angle and the calculated ideal tilting angle is 1.18°. Based on steering and tilting mathematical model of the rollover critical state of the ATTWV, the safe turning speed under the specific tilting angle can be solved, and the value range of the tilting strength coefficient can be obtained, which provides not only a reference for the control of ATTWVs but also a theoretical basis for the research on accurate self-driving control of the active tilting narrow vehicles in the future.

Vehicle dynamics and active rollover stability control of an electric narrow three-wheeled vehicle: a review and concern towards improvement

Narrow electric three-wheeled vehicles are a potential solution to stringent issues of traffic congestion, parking space, vehicular emissions and the fuel crisis. However, narrow three-wheelers have poor manoeuvrability at high speed due to rollover propensity. Researchers have been addressing these conflicting requirements using an active tilt control, a concept of automatic tilting. This paper reviews the different methodologies of tilt control and vehicle dynamics of narrow three-wheeled vehicles, followed by major technical implications. The steering direct tilt control system based on an active steering gain curve has exhibited the substantial potential to control tilting to offer a minimum perceived lateral acceleration and tilting torque, such that the least deviation occurs in the desired path. However, the active steering gain curve can further be optimised by incorporating the desired tilt angle depending upon the rollover index of three-wheelers. The designed control system, including combined lateral and longitudinal dynamics needs to be investigated experimentally under various operating conditions like banked and graded roads, varying friction surfaces and multi-passenger configurations for severe manoeuvres over a large range of vehicle speed.

Research on Model Predictive Control for Automobile Active Tilt Based on Active Suspension

To improve the handling stability of automobiles and reduce the odds of rollover, active or semi-active suspension systems are usually used to control the roll of a vehicle. However, these kinds of control systems often take a zero-roll-angle as the control target and have a limited effect on improving the performance of the vehicle when turning. Tilt control, which actively controls the vehicle to tilt inward during a curve, greatly benefits the comprehensive performance of a vehicle when it is cornering. After analyzing the advantages and disadvantages of the tilt control strategies for narrow commuter vehicles by combining the structure and dynamic characteristics of automobiles, a direct tilt control (DTC) strategy was determined to be more suitable for automobiles. A model predictive controller for the DTC strategy was designed based on an active suspension. This allowed the reverse tilt to cause the moment generated by gravity to offset that generated by the centrifugal force, thereby significantly improving the handling stability, ride comfort, vehicle speed, and rollover prevention. The model predictive controller simultaneously tracked the desired tilt angle and yaw rate, achieving path tracking while improving the anti-rollover capability of the vehicle. Simulations of step-steering input and double-lane change maneuvers were performed. The results showed that, compared with traditional zero-roll-angle control, the proposed tilt control greatly reduced the occupant’s perceived lateral acceleration and the lateral load transfer ratio when the vehicle turned and exhibited a good path-tracking performance.

Integrated Stability Control for Narrow Tilting Vehicles: An Envelope Approach

This paper proposes an integrated stability control strategy for tilting vehicles. The work extends the envelope-based lateral stability controller by introducing and enforcing the roll envelope in the optimal control design. The model predictive controller (MPC) scheme is adopted to apply the control effort only when the predicted vehicle states are leaving the safe envelopes. The non-minimum phase problem in active tilting control is handled by utilizing the predictive feature of the controller. It is shown via the simulation in CarSim that, by adopting the envelope-based control scheme, the control effort to maintain the roll stability of narrow vehicles can be greatly reduced. The integrated controller also improves the vehicle handling performance while still guarantees its lateral and roll stability.

Effects of Tilting Mechanism of Narrow Vehicle on Psychophysiological States of Driver

Narrow tilting vehicles have been proposed to address transportation issues such as traffic congestion, lack of parking space. The investigation of the effects of narrow tilting vehicles on user is insufficient though many methods for improving the stability of those were proposed. The purpose of the present study is to investigate the effects of tilting mechanism of narrow vehicles on psychophysiological states of driver as a fundamental study. Focused on user satisfaction among the components of usability, the hypotheses that a tilting mechanism affects the user’s psychological state, and that the physiological indices such as a frontal alpha asymmetry, beta wave per alpha wave power based on brain activity are valid to evaluate the state were tested. The subjective evaluation of emotional states based on Russell’s circumplex model and the measurement of electroencephalography (EEG) were performed in the experiment using the proposed vehicle with the tilting mechanism. As a result, both the subject evaluation and the physiological indices based on EEG showed a significantly higher value of arousal and valence in the case of the tilting vehicle compared to the control vehicle. These results suggest that both arousal and valence levels of narrow vehicle users can be improved by a tilting mechanism.

Narrow Tilting Vehicles: Mechanism, Dynamics, and Control

Narrow Tilting Vehicles: Mechanism, Dynamics, and Control

A Study on Steering Stability of a Passive Front Wheel on Tilting Narrow Track Vehicle

A Study on Steering Stability of a Passive Front Wheel on Tilting Narrow Track Vehicle

LPV Static Output Feedback for Constrained Direct Tilt Control of Narrow Tilting Vehicles

This brief presents a new direct tilt control (DTC) design to improve the lateral stability and the driving comfort of narrow tilting vehicles. To this end, a conceptual model is constructed from the vehicle dynamics, a simplified model of the driving environment, and the vehicle perceived acceleration. This latter is considered as the main performance variable of the related $\mathcal {H}_{2}$ control problem. The conceptual model is then represented in a polytopic linear parameter varying (LPV) form for control purposes. To avoid the use of costly vehicle sensors while favoring the simplest control structure for real-time implementation, a new LPV static output feedback control method is proposed. Thanks to Lyapunov stability arguments, physical constraints on both system states and DTC actuator are explicitly considered in the design procedure to improve the safety and the comfort of passengers. Moreover, a parameter-dependent Lyapunov function is exploited for theoretical developments. In this way, the finite bounds on vehicle speed and acceleration are effectively taken into account in the control design to reduce the conservatism. The $\mathcal {H}_{2}$ control design is recast as a linear matrix inequality-based optimization which can be easily solved with numerical solvers. The resulting robust DTC controller is evaluated with realistic driving scenarios.

A Reconfigurable Integrated Control for Narrow Tilting Vehicles

This paper proposes a reconfigurable control strategy for vehicles with tilting capabilities including a new rollover control approach. It can be applied to the emerging narrow tilting cars for urban transportation as well as conventional vehicles with semiactive or active suspensions. This paper extends the integrated lateral stability controller by considering the roll degrees of freedom for motion control. An envelope approach based on rollover index is proposed for the high-level controller of the vehicle to manage the rollover stability and the control energy consumption. The desired stabilizing forces are then distributed to available actuators using a reconfigurable optimal control allocation. The reconfigurable approach provides the freedom to select different actuators for the system without redesigning the controller. The optimal control allocation also ensures the feasibility as well as system robustness. It is shown via the simulation in CarSim that, by adopting the proposed control approach, tilting control effort is reduced and the vehicle handling, as well as stability in both lateral and roll motions, can be furthered improved.

A study on usability of narrow track vehicle utilizing physiological indices

A study on usability of narrow track vehicle utilizing physiological indices

Analysis of a construction solution for narrow track vehicle (NTV)

At present, automotive industry and as well as car drivers are faced with increase of new challenges such as new emission limits, increased traffic congestion and reduced parking spaces in cities. All these challenges are leading to changes in consumer preferences and the requirements for modern passenger vehicles. The basic layout of today’s car has not changed much since its invention and it is not suited to solving today’s problems. An average conventional vehicle is still four wheeled box growing bigger every year. In Europe and the US, the average number of occupants of a single vehicle is about 1.52. It is clear that the current vehicle size is highly underutilized. The cities are getting more and more congested due to the use of motor vehicle for commuting. Building highway infrastructure at the same growth rate as a number of vehicles is not a feasible solution. It is expected that narrow track vehicle (NTV’s) would be the solution all for these problems. In many countries a number of alternative commuting vehicle have been developed. NTV’s are the convergence of a car and a motorcycle, i.e. with smaller dimensions and reduced energy consumption and pollutant emission. In this paper the analysis of construction solutions for a narrow track vehicle, considering their stability, safety problems as well as other factors will be presented. The author’s concepts of a narrow vehicle are also presented Two small narrow cars were designed at CUT.

Modelling and simulation of narrow car dynamic

Torque vectoring has huge impact on vehicles steering characteristics. Most of the literature refer to the vehicles with a wheel track typical for passenger cars. This paper examines whether for the narrow vehicle (with a very small wheel track) torque vectoring is possible to be used in an active safety systems, securing it from roll over (roll mitigation). This paper deals with the description of current vehicle technology related to traction control through the employment of effective torque vectoring strategies for electric vehicles. The work contains a description of simulation models. The bicycle model of a vehicle is arranged and suitable adapted for the test subject. The paper contains a set of simulation compared with road tests of the narrow vehicle. The usefulness of a simple linear single track vehicle model to describe the movement was tested. The vehicle understeer characteristic as a function of a power distribution is presented.

A Study on the Design of Rear Wheel Drive Reducer for Electric Vehicle

The aim of this study is to design the gearbox of an electric vehicle using the rear-wheel drive. The gearbox is a set of revolving gears and shafts based on programmed torque and rotations per minute (rpm). In this case, safety, strength and durability of gears and shafts was considered. In the narrow vehicle, a light case is used. In addition to gear safety and deflection, the weight of the vehicle was reduced. The electric vehicle reducer gearbox was modeled according to the vehicle room. The strength analysis was conducted using finite element method (FEM). After analyzing the strength using FEM to verify stress distribution, the design was modified, and compared with the results of altered design using FEM. As a result, the reducer gearbox of electric vehicle was designed according to incorporate gear safety, deflection of each gear, durability, and analysis of finite elements followed by test assessment, vehicle installation and the production of real parts.

Development of A Novel Integrated Corner Module for Narrow Urban Vehicles

Most current urban vehicles are scaled-down versions of standard passenger cars. This imposes serious limitations on the safety, comfort, efficiency, dynamic performance and, hence, customer acceptance of the vehicle. This paper provides a unique design of an integrated corner module including an in-wheel suspension, an electrical in-wheel motor, a friction brake, a steering system, and a camber mechanism, which can be used in any urban vehicle design without modification. For the first time, a dual four-bar linkage mechanism has been designed to generate a virtual kingpin axis and provide an active camber. This approach results in a highly compact design for the corner module that can be integrated into narrow vehicles. A full-size prototype of the proposed integrated corner module has been fabricated and tested to validate the new steering mechanism and the integrated corner module characteristics.

A novel integrated suspension tilting system for narrow urban vehicles

Narrow vehicles are proposed to resolve urban transportation issues such as congestion, parking, fuel consumption and pollution. They are characterized by a high ratio of centre of gravity height over track width. Such vehicles are vulnerable to rollover and stability issues when negotiating curves at a normal operating speed. Therefore, the tilting capability is crucial to such vehicles. Existing solutions, which mechanically connect the wheel module on both sides and synchronize their movement, still have room for further improvement. The extra links for synchronization not only take up space on compact urban vehicles, but also introduce additional mass to the light-weighted body. The novel tilting mechanism introduced in this work utilizes hydraulics to replace mechanical connections to generate the tilting motion. An interconnected hydro-pneumatic suspension system is adopted to provide the desired bump and roll stiffness for narrow urban vehicle applications. Two independently controlled hydraulic pumps are connected to the hydraulic suspensions to provide the tilting, as well as riding height change capabilities. The integration of the tilting system with suspension reduces the system weight and packing size, both of which are vital to the success of narrow urban vehicles. All the functionalities are illustrated, modelled and examined in the simulation studies, which prove the feasibility of the proposed system on narrow urban vehicle applications resulting in more functionalities with lower complexity and weight.

Design and analysis of an integrated suspension tilting mechanism for narrow urban vehicles

This paper presents the design of an integrated suspension tilting mechanism for narrow tilting vehicles. The challenge in the design of such suspension tilting mechanisms is to allow large suspension travels to generate sufficient tilting angles to balance the vehicle in cornering, while at the same time remain as compact as possible to save the space for passengers and cargos. Existing solutions, which are mostly based on parallel mechanisms, are not space-friendly and add extra weight to the expected compact and light-weighted urban vehicles. This paper firstly examines the feasibility of various automobile suspension mechanisms by considering their complexity and space requirements, and identifies the trailing arm mechanism as a promising solution. Then the kinematic and dynamic properties of the vehicle during large suspension heave motions are examined to establish guidelines for detailed mechanism design. Finally, more detailed constraints and objectives are considered to arrive at an optimal design. Simulation results confirm that the longitudinal movement of the wheel can be utilized to improve vehicle stability.

Torque vectoring for improving stability of small electric vehicles

The electric vehicles solutions based on the individually controlled electric motors propel a single wheel allow to improve the dynamic properties of the vehicle by varying the distribution of the driving torque. Most of the literature refer to the vehicles with a track typical for passenger cars. This paper examines whether the narrow vehicle (with a very small track) torque vectoring bring a noticeable change of the understeer characteristics and whether torque vectoring is possible to use in securing a narrow vehicle from roll over (roll mitigation). The paper contains road tests of the steering characteristics (steady state understeer characteristic quasi-static acceleration with a fixed steering wheel (SH = const) and on the constant radius track (R = const)) of the narrow vehicle. The vehicle understeer characteristic as a function of a power distribution is presented.

Steering Dynamics of Tilting Narrow Track Vehicle with Passive Front Wheel Design

In recent years, narrow track vehicle has been emerged as a potential candidate for the next generation of urban transportation system, which is greener and space effective. Vehicle body tilting has been a symbolic characteristic of such vehicle, with the purpose to maintain its stability with the narrow track body. However, the coordination between active steering and vehicle tilting requires considerable driving skill in order to achieve effective stability. In this work, we propose an alternative steering method with a passive front wheel that mechanically follows the vehicle body tilting. The objective of this paper is to investigate the steering dynamics of the vehicle under various design parameters of the passive front wheel. Modeling of a three-wheel tilting narrow track vehicle and multibody dynamics simulations were conducted to study the effects of two important front wheel design parameters, i.e. caster angle and trail toward the vehicle steering dynamics in steering response time, turning radius, steering stability and resiliency towards external disturbance. From the results of the simulation studies, we have verified the relationships of these two front wheel design parameters toward the vehicle steering dynamics.