scholarly journals Stable trajectory planning and energy-efficience control allocation of lane change maneuver for autonomous electric vehicle

2018 ◽  
Vol 1 (2) ◽  
pp. 55-65
Author(s):  
Liwei Xu ◽  
Guodong Yin ◽  
Guangmin Li ◽  
Athar Hanif ◽  
Chentong Bian
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Electric Vehicles ◽  
Lateral Acceleration ◽  
Lane Change ◽  
Stability Boundaries ◽  
Content Type ◽  
Yaw Rate ◽  
Stable Trajectory ◽  
Autonomous Electric Vehicles

Purpose The purpose of this paper is to investigate problems in performing stable lane changes and to find a solution to reduce energy consumption of autonomous electric vehicles. Design/methodology/approach An optimization algorithm, model predictive control (MPC) and Karush–Kuhn–Tucker (KKT) conditions are adopted to resolve the problems of obtaining optimal lane time, tracking dynamic reference and energy-efficient allocation. In this paper, the dynamic constraints of vehicles during lane change are first established based on the longitudinal and lateral force coupling characteristics and the nominal reference trajectory. Then, by optimizing the lane change time, the yaw rate and lateral acceleration that connect with the lane change time are limed. Furthermore, to assure the dynamic properties of autonomous vehicles, the real system inputs under the restraints are obtained by using the MPC method. Based on the gained inputs and the efficient map of brushless direct-current in-wheel motors (BLDC IWMs), the nonlinear cost function which combines vehicle dynamic and energy consumption is given and the KKT-based method is adopted. Findings The effectiveness of the proposed control system is verified by numerical simulations. Consequently, the proposed control system can successfully achieve stable trajectory planning, which means that the yaw rate and longitudinal and lateral acceleration of vehicle are within stability boundaries, which accomplishes accurate tracking control and decreases obvious energy consumption. Originality/value This paper proposes a solution to simultaneously satisfy stable lane change maneuvering and reduction of energy consumption for autonomous electric vehicles. Different from previous path planning researches in which only the geometric constraints are involved, this paper considers vehicle dynamics, and stability boundaries are established in path planning to ensure the feasibility of the generated reference path.

scholarly journals Coordinated Stability Control Strategy for Intelligent Electric Vehicles Using Vague Set Theory

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yilin He ◽  
Jian Ma ◽  
Xuan Zhao ◽  
Ruoyang Song ◽  
Xiaodong Liu ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Control Strategy ◽  
Coordinated Control ◽  
Stability Control ◽  
Lateral Acceleration ◽  
Vague Set ◽  
Yaw Rate ◽  
Stability Performance ◽  
Control Target ◽  
Simulation Results

Aiming at improving the tracking stability performance for intelligent electric vehicles, a novel stability coordinated control strategy based on preview characteristics is proposed in this paper. Firstly, the traditional stability control target is introduced with the two degrees of freedom model, which is realized by the sliding mode control strategy. Secondly, an auxiliary control target further amending the former one with the innovation formulation of the preview characteristics is established. At last, a multiple purpose Vague set leverages the contribution of the traditional target and the auxiliary preview target in various vehicle states. The proposed coordinated control strategy is analyzed on the MATLAB/CarSim simulation platform and verified on an intelligent electric vehicle established with A&D5435 rapid prototyping experiment platform. Simulation and experimental results indicate that the proposed control strategy based on preview characteristics can effectively improve the tracking stability performance of intelligent electric vehicles. In the double lane change simulation, the peak value of sideslip angle, yaw rate, and lateral acceleration of the vehicle is reduced by 13.2%, 11.4%, and 8.9% compared with traditional control strategy. The average deviations between the experimental and simulation results of yaw rate, lateral acceleration, and steering wheel angle are less than 10% at different speeds, which demonstrates the consistency between the experimental and the simulation results.

Effects of the actively morphing root chord and taper on helicopter energy

2019 ◽  
Vol 92 (2) ◽  
pp. 264-270
Author(s):  
Firat Sal
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Flight Control ◽  
Design Methodology ◽  
Chord Length ◽  
Flight Control System ◽  
Content Type ◽  
Helicopter Blade ◽  
Blade Root ◽  
Practical Implications

Purpose The purpose of this paper presents the effects of actively morphing root chord and taper on the energy of the flight control system (i.e. FCS). Design/methodology/approach Via regarding previously mentioned purposes, sophisticated and realistic helicopter models are benefitted to examine the energy of the FCS. Findings Helicopters having actively morphing blade root chord length and blade taper consume less control energy than the ones having one of or any of passively morphing blade root chord length and blade taper. Practical implications Actively morphing blade root chord length and blade taper can be used for cheaper helicopter operations. Originality/value The main originality of this paper is applying active morphing strategy on helicopter blade root chord and blade taper. In this paper, it is also found that using active morphing strategy on helicopter blade root chord and blade taper reasons less energy consumption than using either passively morphing blade root chord length plus blade taper or not any. This causes also less fuel consumption and green environment.

Torque vectoring control system for distributed drive electric bus under complicated driving conditions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liang Su ◽  
Zhenpo Wang ◽  
Chao Chen
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Steering Wheel ◽  
Content Type ◽  
Yaw Rate ◽  
Torque Vectoring ◽  
Driving Conditions ◽  
Yaw Moment

Purpose The purpose of this study is to propose a torque vectoring control system for improving the handling stability of distributed drive electric buses under complicated driving conditions. Energy crisis and environment pollution are two key pressing issues faced by mankind. Pure electric buses are recognized as the effective method to solve the problems. Distributed drive electric buses (DDEBs) as an emerging mode of pure electric buses are attracting intense research interests around the world. Compared with the central driven electric buses, DDEB is able to control the driving and braking torque of each wheel individually and accurately to significantly enhance the handling stability. Therefore, the torque vectoring control (TVC) system is proposed to allocate the driving torque among four wheels reasonably to improve the handling stability of DDEBs. Design/methodology/approach The proposed TVC system is designed based on hierarchical control. The upper layer is direct yaw moment controller based on feedforward and feedback control. The feedforward control algorithm is designed to calculate the desired steady-state yaw moment based on the steering wheel angle and the longitudinal velocity. The feedback control is anti-windup sliding mode control algorithm, which takes the errors between actual and reference yaw rate as the control variables. The lower layer is torque allocation controller, including economical torque allocation control algorithm and optimal torque allocation control algorithm. Findings The steady static circular test has been carried out to demonstrate the effectiveness and control effort of the proposed TVC system. Compared with the field experiment results of tested bus with TVC system and without TVC system, the slip angle of tested bus with TVC system is much less than without TVC. And the actual yaw rate of tested bus with TVC system is able to track the reference yaw rate completely. The experiment results demonstrate that the TVC system has a remarkable performance in the real practice and improve the handling stability effectively. Originality/value In view of the large load transfer, the strong coupling characteristics of tire , the suspension and the steering system during coach corning, the vehicle reference steering characteristics is defined considering vehicle nonlinear characteristics and the feedforward term of torque vectoring control at different steering angles and speeds is designed. Meanwhile, in order to improve the robustness of controller, an anti-integral saturation sliding mode variable structure control algorithm is proposed as the feedback term of torque vectoring control.

scholarly journals Effects of feature selection on lane-change maneuver recognition: an analysis of naturalistic driving data

2018 ◽  
Vol 1 (3) ◽  
pp. 85-98 ◽  
Author(s):  
Xiaohan Li ◽  
Wenshuo Wang ◽  
Zhang Zhang ◽  
Matthias Rötting
Keyword(s):  
Feature Selection ◽  
Recognition Performance ◽  
Feature Selection Method ◽  
Model Performance ◽  
Computation Time ◽  
Poor Performance ◽  
Lateral Acceleration ◽  
Lane Change ◽  
Content Type ◽  
Naturalistic Driving

PurposeFeature selection is crucial for machine learning to recognize lane-change (LC) maneuver as there exist a large number of feature candidates. Blindly using feature could take up large storage and excessive computation time, while insufficient feature selection would cause poor performance. Selecting high contributive features to classify LC and lane-keep behavior is effective for maneuver recognition. This paper aims to propose a feature selection method from a statistical view based on an analysis from naturalistic driving data.Design/methodology/approachIn total, 1,375 LC cases are analyzed. To comprehensively select features, the authors extract the feature candidates from both time and frequency domains with various LC scenarios segmented by an occupancy schedule grid. Then the effect size (Cohen’s d) andp-value of every feature are computed to assess their contribution for each scenario.FindingsIt has been found that the common lateral features, e.g. yaw rate, lateral acceleration and time-to-lane crossing, are not strong features for recognition of LC maneuver as empirical knowledge. Finally, cross-validation tests are conducted to evaluate model performance using metrics of receiver operating characteristic. Experimental results show that the selected features can achieve better recognition performance than using all the features without purification.Originality/valueIn this paper, the authors investigate the contributions of each feature from the perspective of statistics based on big naturalistic driving data. The aim is to comprehensively figure out different types of features in LC maneuvers and select the most contributive features over various LC scenarios.

Study on Energy-Saving Driving Mode during Cornering for Motorized Wheels Driving Vehicle

2012 ◽  
Vol 203 ◽  
pp. 360-364
Author(s):  
Huan Huan Zhang ◽  
Guo Ping Yang
Keyword(s):  
Energy Consumption ◽  
Power Consumption ◽  
Energy Saving ◽  
Constant Speed ◽  
Lateral Acceleration ◽  
Resistance Force ◽  
Vehicle Model ◽  
Torque Distribution ◽  
Driving Mode ◽  
Yaw Rate

In order to study the energy consumption feature when cornering for motorized wheels driving vehicles, the resistance force on the driving axle was analyzed. A creative method quasi-neutral steering was proposed for vehicle cornering. A motorized wheels driving vehicle model was established, and the simulation of constant speed cornering was performed when the yaw rate as the parameter to control the front-rear torque distribution and the lateral acceleration as the parameter to control the left-right torque distribution. The results indicate that no wheel slipping is happened when quasi-neutral steering. The torque on the rear outer wheel is more than other wheels, and the torque on the outer wheels is more than inner wheels. The power consumption decreases 1.15% by quasi-neutral steering.

scholarly journals INTEGRATION OF MOTION PLANNING AND MODEL-PREDICTIVE-CONTROL-BASED CONTROL SYSTEM FOR AUTONOMOUS ELECTRIC VEHICLES

Transport ◽  
2015 ◽  
Vol 30 (3) ◽  
pp. 353-360 ◽  
Author(s):  
Guodong Yin ◽  
Jianghu Li ◽  
Xianjian Jin ◽  
Chentong Bian ◽  
Nan Chen
Keyword(s):  
Control System ◽  
Model Predictive Control ◽  
Motion Planning ◽  
Predictive Control ◽  
Electric Vehicles ◽  
Autonomous Driving ◽  
Planning System ◽  
Time Interval ◽  
Physical Constraints ◽  
Autonomous Electric Vehicles

This paper introduces the development of an autonomous driving system in autonomous electric vehicles, which consists of a simplified motion-planning program and a Model-Predictive-Control-Based (MPC-based) control system. The motion-planning system is based on polynomial parameterization, which computes a path toward the expected longitudinal and lateral positions within required time interval in real scenarios. Then the MPC-based control system cooperates the front steering and individual wheel torques to track the planned trajectories, while fulfilling the physical constraints of actuators. The proposed system is evaluated through simulation, using a seven-degrees-offreedom vehicle model with a ‘magic formula’ tire model. The simulations and validation through CarSim show that the proposed planner algorithm and controller are feasible and can achieve requirements of autonomous driving in normal scenarios.

Design of an integrated control system to enhance vehicle roll and lateral dynamics

2017 ◽  
Vol 40 (5) ◽  
pp. 1435-1446 ◽  
Author(s):  
Shahab Rahimi ◽  
Mahyar Naraghi
Keyword(s):  
Control System ◽  
Load Transfer ◽  
Integrated Control ◽  
Independent Study ◽  
Lateral Acceleration ◽  
Lateral Instability ◽  
Sideslip Angle ◽  
Roll Control ◽  
Coordination Strategy ◽  
Yaw Rate

Besides lateral instability, one major threat to all ground vehicles, especially SUVs, is the danger of rollover during cornering. A coordination strategy based on fuzzy logic has been devised to coordinate the sub-controls; namely, active steering, active differential, active brake and a novel active roll control system. Independent study of each sub-control as well as an analysis of their inter-relationship has been carried out. The coordination strategy is supposed to resolve the conflict among control targets – which are sideslip regulation, yaw rate tracking, lateral acceleration tracking and roll motion control – all of which are to be done while maintaining the driver’s desired longitudinal acceleration. Thus, a compromise must be reached. Vehicle sideslip angle and yaw rate were considered to be the criteria for lateral stability; and a combination of roll angle, roll rate and lateral load transfer was selected as the criterion for roll stability. The results of simulations on two SUV models in CarSim software indicate that the integrated controller can successfully restore vehicles’ stability in critical condition.

A Torque Vectoring Control System for Maneuverability Improvement of 4WD EV

2013 ◽  
Vol 347-350 ◽  
pp. 899-903
Author(s):  
Yi He Gan ◽  
Lu Xiong ◽  
Yuan Feng ◽  
Felix Martinez
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Lower Layer ◽  
Lateral Acceleration ◽  
Slip Angle ◽  
Torque Distribution ◽  
Handling Performance ◽  
Yaw Rate ◽  
Model Following ◽  
Torque Vectoring

This paper studies the improvement of the handling performance of 4WD EV driven by in-wheel motors under regular driving conditions. Fundamentally the structure of torque vectoring control (TVC) system for handling control consists of two control layers. The upper layer is a model following controller which makes the vehicle follow the desired yaw rate limited by the side slip angle and lateral acceleration. The torque distribution constitutes the lower layer. Several simulations based on veDYNA/Simulink are conducted to verify the effectiveness of the control system. It is clarified that the control system exhibits satisfactory performance in both open and closed loop maneuvers and the agility of the electric vehicle is improved.

scholarly journals The Energy Consumption of Passenger Vehicles in a Transformed Mobility System with Autonomous, Shared and Fit-For-Purpose Electric Vehicles in the Netherlands

2021 ◽  
Vol 15 (1) ◽  
pp. 201-209
Author(s):  
Peter Hogeveen ◽  
Maarten Steinbuch ◽  
Geert Verbong ◽  
Auke Hoekstra
Keyword(s):  
Energy Consumption ◽  
The Netherlands ◽  
Electric Vehicles ◽  
Energy Use ◽  
Autonomous Driving ◽  
Passenger Transport ◽  
Passenger Vehicles ◽  
Mobility System ◽  
Fit For Purpose ◽  
Autonomous Electric Vehicles

Aims: This article explores the tank-to-wheel energy consumption of passenger transport at full adoption of fit-for-purpose shared and autonomous electric vehicles. Background: The energy consumption of passenger transport is increasing every year. Electrification of vehicles reduces their energy consumption significantly but is not the only disruptive trend in mobility. Shared fleets and autonomous driving are also expected to have large impacts and lead to fleets with one-person fit-for-purpose vehicles. The energy consumption of passenger transport in such scenarios is rarely discussed and we have not yet seen attempts to quantify it. Objective: The objective of this study is to quantify the tank-to-wheel energy consumption of passenger transport when the vehicle fleet is comprised of shared autonomous and electric fit-for-purpose vehicles and where cheap and accessible mobility leads to significantly increased mobility demand. Methodology: The approach consists of four steps. First, describing the key characteristics of a future mobility system with fit-for-purpose shared autonomous electric vehicles. Second, estimating the vehicle miles traveled in such a scenario. Third, estimating the energy use of the fit-for-purpose vehicles. And last, multiplying the mileages and energy consumptions of the vehicles and scaling the results with the population of the Netherlands. Results: Our findings show that the daily tank-to-wheel energy consumption from Dutch passenger transport in full adoption scenarios of shared autonomous electric vehicles ranges from 700 Wh to 2200 Wh per capita. This implies a reduction of 90% to 70% compared to the current situation. Conclusion: Full adoption of shared autonomous electric vehicles could increase the vehicle-miles-travelled and thus energy use of passenger transport by 30% to 150%. Electrification of vehicles reduces energy consumption by 75%. Autonomous driving has the potential of reducing the energy consumption by up to 40% and implementing one-person fit-for-purpose vehicles by another 50% to 60%. For our case study of the Netherlands, this means that the current 600 TJ/day that is consumed by passenger vehicles will be reduced to about 50 to 150 TJ/day at full adoption of SAEVs.

scholarly journals Improving the directional stability of a traction control system without additional sensors

2002 ◽  
Vol 216 (8) ◽  
pp. 641-648 ◽  
Author(s):  
H Jung ◽  
B Kwak ◽  
Y Park
Keyword(s):  
Control System ◽  
Degrees Of Freedom ◽  
Lateral Acceleration ◽  
Slip Ratio ◽  
Traction Control ◽  
Additional Information ◽  
Yaw Rate ◽  
Traction Control System ◽  
Directional Stability ◽  
Acceleration Sensors

The traction control system (TCS) comprises a slip control subsystem and a directional stability subsystem. The slip controller can enhance the traction performance by maintaining the slip ratio within an appropriate range. Additional information about the lateral behaviour of the vehicle is necessary to enhance the directional stability during cornering or lane change on slippery roads. With an assumption of slowly varying steering input, a new method to measure the mixture of yaw rate and lateral acceleration, using the speed difference of non-driven wheels, is proposed. Using this measurement, the controller imposes independent pressure to each driven wheel and improves the stability during cornering on slippery roads or acceleration on split-μ roads without additional sensors such as yaw rate and lateral acceleration sensors. The proposed method is verified through simulation based on a 15-degrees-of-freedom (15 DOF) passenger car model.

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