State Estimation of Drive-by-Wire Chassis Vehicle Based on Dual Unscented Particle Filter Algorithm

Accurate vehicle dynamic information plays an important role in vehicle driving safety.However,due to the characteristics of high mobility and multiple controllable degrees of freedom of drive-by-wire chassis vehicles,the current mature application of traditional vehicle state estimation algorithms can not meet the requirements of drive-by-wire chassis vehicle state estimation.This paper proposes a state estimation method for drive-by-wire chassis vehicle based on the dual unscented particle filter algorithm,which make full use of the known advantages of the four-wheel drive torque and steer angle parameters of the drive-by-wire chassis vehicle.In the dual unscented particle filter algorithm,two unscented particle filter transfer information to each other,observe the vehicle state information and the tire force parameter information of the four wheels respectively,which reduce the influence of parameter uncertainty and model parameter changes on the estimation accuracy during driving.The performance with the dual unscented particle filter algorithm,which is analyzed in terms of the time-average square error,is superior of the unscented Kalman filter algorithm.The effectiveness of the algorithm is further verified by driving simulator test.In this paper,a vehicle state estimator based on dual unscented particle filter algorithm was proposed for the first time to improve the estimation accuracy of vehicle parameters and states.

Research on X-by-Wire Chassis Technology for Intelligent Driving of New Energy Vehicles

As China’s economy develops,new energy technologies and intelligent driving have become a trend in the automobile industry.The development of new energy vehicles has accelerated,with X-by-wire chassis technology becoming the core technology for intelligent driving.This technology includes steer-,brake-,shift-,and throttle-by-wire systems.It is not only the key technology for new energy vehicles but also an important support for promoting their sustainable development.This article presents an in-depth study on X-by-wire chassis technology in new energy vehicles and its basic working principle.

Robot driver for vehicle durability emission test on chassis dynamometer

A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.

Chassis Coordinated Control for Full X-by-Wire Vehicles-A Review

An X-by-wire chassis can improve the kinematic characteristics of human-vehicle closed-loop system and thus active safety especially under emergency scenarios via enabling chassis coordinated control.This paper aims to provide a complete and systematic survey on chassis coordinated control methods for full X-by-wire vehicles,with the primary goal of summarizing recent reserch advancements and stimulating innovative thoughts.Driving condition identification including driver’s operation intention,critical vehicle states and road adhesion condition and integrated control of X-by-wire chassis subsystems constitute the main framework of a chassis coordinated control scheme.Under steering and braking maneuvers,different driving condition identification methods are described in this paper.These are the trigger conditions and the basis for the implementation of chassis coordinated control.For the vehicles equipped with steering-by-wire,braking-by-wire and/or wire-controlled-suspension systems,state-of-the-art chassis coordinated control methods are reviewed including the coordination of any two or three chassis subsystems.Finally,the development trends are discussed.

An improved LuGre model for calculating static steering torque of rubber tracked chassis

Tire and rubber track interchangeable chassis combines the advantages of tire and rubber track,which can greatly improve the maneuverability of military construction machinery.However,there is almost no effective calculation model for the real-time static steering torque.When the relative sliding speed is greater than 0.01 m/s,the influence of friction heating can not be ignored.An improved LuGre model is established to calculate the static real-time steering torque of tire and rubber track interchangeable chassis.Firstly,the friction heating model between rubber and ground is established.Combined with the influence of temperature on the dynamic performance of rubber material,the influence of friction heating on the stiffness and friction coefficient of rubber track is analyzed,and the improved LuGre friction model is established.The steering torque of tire and rubber track interchangeable chassis is affected by rubber material properties,steering speed,pavement type,and ambient temperature.Compared with the original Lu Gre model,the improved LuGre model captures the change in friction torque during multiple in-situ turns due to frictional heating.The error with the experimental data is small,which verifies the effectiveness of the improved LuGre model.

基于ADAMS/Chassis的汽车操纵稳定性能仿真分析及优化

应用多体动力学仿真软件ADAMS的chassis模块建立了车辆虚拟样机模型,根据ISO标准进行了稳态回转和方向盘角阶跃两项试验的仿真,计算并分析了两种试验状态下车辆状态参数的变化情况。最后对车辆模型进行了优化,优化结果表明,悬架的结构及材料对操纵稳定性能有一定的影响。

Experimental Study on the Ride Comfort of a Crawler Power Chassis Scale Model Based on the Similitude Theory

The ride comfort experimental assessment of crawler off-road vehicle is relatively overlooked, and is expensive and difficult to execute with higher and higher ride comfort performance requirements. To trade off between precise and cost, an experimental method based on the similitude theory is proposed. Under the guidance of the similitude theory, a 1：5 crawler power chassis scale model equipped with a kind of variable stiffness suspension system is used. The power spectrum density（PSD）, the root mean square（RMS） of weighed acceleration, peak factor, average absorbed power（AAP） and vibration dose value（VDV） are selected as ride comfort evaluation indexes, and tests results are transformed via similarity indexes to predict the performance of full-scale power chassis. PSD shows that the low-order natural frequency of the vertical natural frequency（z axis） is 1.1 Hz, and the RMS, AAP and VDV values indicate the ride comfort performance of this kind of power chassis is between the ＂A little uncomfortable＂ and ＂Rather uncomfortable＂. From the results, low-order vertical natural frequency, obtained by PSD, validates that the similarity relationship between two models is satisfied, and 1：5 scale model used in experiment meets the similarity relationship with the full-scale model; consequently, the ride comfort prophase evaluation with the 1：5 scale model is feasible. The attempt of applying the similitude theory to crawler vehicle ride comfort test study decreases the cost and improves the test feasibility with sufficient test precise.

Virtual Prototype Simulation and Reliability Analysis for Drive System of Armored Chassis

Drive system is the key device of armored chassis. Its working state and reliability influence the maneuver performance of armored chassis directly. In order to simulate the failure process and evaluate the service reliability of drive system in training or battle missions,a new kind of dynamic simulation model and driving simulation platform of the complete drive system were established based on virtual prototype and finite element technology in this paper. Using the platform, the kinematics and dynamic characteristics of drive system were studied and analyzed in detail,the dynamic load spectrum of key components was obtained,the service life was predicted, and the service reliability evaluation results were provided. A simulation example of transmission gear was shown to illustrate the simulation and evaluation process. The result proves that the simulation method not only can be used to compute and evaluate the service reliability of complex mechanical mechanism, but also has high precision and reasonable computational cost. Therefore,simulation and reliability analysis based on virtual prototype of the armored chassis drive system will provide scientific reference for the formulation of armored chassis reasonable repair cycle.

A flexible multi-body model of a surface miner for analyzing the interaction between rock-cutting forces and chassis vibrations

The discontinuous nature of rock cutting can easily cause unwanted vibrations in the structure of a surface miner.If these vibrations are not properly addressed,the related stress cycles can gradually damage the chassis resulting in fatigue failures.These events can seriously undermine the safety of operators and digging operations may be stopped for days,with an obvious economic impact.This work presents an analysis of the dynamics of a surface miner,focusing on the interaction between cutting machine dynamics and cutting forces,which is a new approach for this type of machine.For this purpose,the authors developed a numerical model of the cutting process made up of(1)a multi-body model of the cutting machine,which takes into account the chassis's flexibility;(2)a model of the rotating cutting head;and(3)a model of the interaction between the cutting head and rock,based on Shao's model.The model was compared with experimental results and then used to investigate the effects of cutting speed and cutting depth on the machine dynamics.

Chassis tra fficability simulation and experiment of a LY1352JP forest tracked vehicle

Based on the analysis of complex terrains and current forest transportation equipment,a forest tracked vehicle prototype LY1352 JP was developed.The road model and the virtual prototype of the chassis were constructed using dynamic simulation software RecurDyn.The optimal tension of the vehicle as well as its capabilities for crossing trenches,climbing vertical walls,uphill and downhill slopes were simulated.The simulation results showed that the optimum tension force of the chassis of the vehicle was 63 kN(kilonewton),accounting for 45%of the total vehicle weight.The maximum trench crossing width and vertical obstacle climbing height were 1.35 m and 0.45 m,respectively.The maximum uphill and downhill angles were 50°and 45°,respectively.Tests on the prototype capacity for crossing trenches,and uphill and downhill driving were carried out.The test results were in agreement with the simulation results.A cross-country performance of a fire truck based on the tracked vehicle chassis was conducted in an old-growth forest.Tests verified that the vehicle has a strong forest trafficability performance and can meet the needs for forest transportation.

Structure analysis of levitation chassis of medium-to-low speed maglev vehicles based on left-right decoupling

Levitation chassis, as an extremely important component of maglev vehicles, provides functions of transmitting levitation force and steering force, and directly affects the safety performance of the vehicle. Based on the vertical dynamics model of the levitation chassis, kinetic equations of the model are established, and a simulation program is designed to analyze the structural decoupling function of the chassis, especially under the influence of elastic constraints between the left and right modules, which are exclusively owned by maglev vehicles. A finite element model of the levitation chassis based on left-right decoupling is constructed. Analysis results of the model show that the mechanical properties of the chassis tailored for the vehicle meet the design requirements, and the stiffness and strength is adequate to bear the weight of the whole vehicle.

Modal Correlation Based Analysis on Dynamic Characters of a Commercial Semi-Trailer's Chassis Frames

In order to evaluate two different schemes＇ structural dynamic characters, dynamic response analysis of a commercial truck＇s main chassis frames is carried out. On the basis of correlation study between the tested and calculated modal results, the assembled frames＇ finite element analysis （FEA） models with sufficient precision are built up. Random response analysis in frequency domain is carried out with these FEA models, RMS values of yon Mises and main principle stresses of these two frames are obtained. It shows that the analysis resuits of the distributing tendency and concrete value ranges are coincident very well with test results. And from the results, it could be concluded that frames of scheme A endures relative better loading conditions and should be adopted as the final scheme.

Seismic response reduction analysis of large chassis base-isolated structure under long-period ground motions

Long-period structures(e.g.Isolated structures)tend to produce pseudo-resonance with low frequency compo-nents of long-period ground motions,resulting in the increase in damage.Stiffness mutation occurs due to the set-back in the upper body of the large chassis structure.In the parts with stiffness mutation,the torsion effect caused by the tower is far greater than that of the chassis itself.In this study,a total of 273 ground motions are collected and then filtered into four types,including the near-field ordinary,near-field pulse,far-field ordinary,and far-field harmonic.An 8-degree(0.2 g)fortified large chassis base-isolated structure is established.Furthermore,ETABS program software is used to conduct nonlinear time history analysis on the isolation and seismic model under bi-directional earthquake ground motions.The comparison results show that the seismic isolation effect of the base-isolated structure under long-period ground motions is worse than that associated with ordinary ground motions when the seismic response reduction rate of the large base floor significantly decreases compared with that of the tower.When the inter-story displacement angle and the displacement of isolation layer of the chassis exceeds the limit of Code for Seismic Design of Buildings(GB 50011-2010),it is recommended to adopt composite seismic isolation technology or add limit devices.Under the condition of long-period ground motions,the base-isolated structure reduces the lateral-torsional coupling effect of the large chassis structure,while the torsion response of large chassis’top layer increases.Under long-period ground motions with the same acceleration peak,the response of the base-isolated structure increases much more than that of the seismic structure and the consideration of this impact is suggested to be added to the Code.

Numerical Analysis of Thermal Convection in a CPU Chassis

Flow distribution and the effects of different boundary conditions are achieved for a steady-state conjugate (Conduction & Convection) heat transfer process. A plate fin heat sink with horizontal fin orientation along with a computer chassis is numerically investigated and simulated using software ANSYS CFX. Fin orientation of a heat sink changes the direction of fluid flow inside the chassis. For predicting turbulence of the flow inside the domain, a two-equation based k-ε turbulence model is chosen. The Reynolds number based on inflow velocity and geometry is found 4.2 × 103 that indicates that the flow is turbulent inside the chassis. To get proper thermal cooling, the optimum velocity ratio of inlet/outlet, dimension of inlet/outlet and different positions of outlet on the back sidewall of the chassis are predicted. Aspect velocity ratio between the inlet airflow and the outlet airflow has an effect on the steadiness of the flow. Mass flow rate depends on the dimension of the inlet/outlet. The horizontal fin orientation with 1:1.6 inlet-outlet airflow velocity ratio gives better thermal performance when outlet is located at the top corner of the chassis, near to the inner sidewall. Flow distribution and heat transfer characteristics are also analyzed to obtain the final model.

Design-build-test of recombinant Bacillus subtilis chassis cell by lifespan engineering for robust bioprocesses

Microbial cell factories utilize renewable raw materials for industrial chemical production,providing a promising path for sustainable development.Bacillus subtilis is widely used in industry for its food safety properties,but challenges remain in the limitations of microbial fermentation.This study proposes a novel strategy based on lifespan engineering to design robust B.subtilis chassis cells to supplement traditional metabolic modification strategies that can alleviate cell autolysis,tolerate toxic substrates,and get a higher mass transfer efficiency.The modified chassis cells could produce high levels of L-glutaminase,and tolerate hydroquinone to produceα-arbutin efficiently.In a 5 L bioreactor,the L-glutaminase enzyme activity of the final strain CRE15TG was increased to 2817.4±21.7 U m L^(-1),about 1.98-fold compared with that of the wild type.Theα-arbutin yield of strain CRE15A was increased to 134.7 g L^(-1),about 1.34-fold compared with that of the WT.To our knowledge,both of the products in this study performed the highest yields reported so far.The chassis modification strategy described in this study can Improve the utilization efficiency of chassis cells,mitigate the possible adverse effects caused by excessive metabolic modification of engineered strains,and provide a new idea for the future design of microbial cell factories.

Investigation of performance and emission characteristics using ethanol-blended gasoline fuel as a flex-fuel in two-wheeler vehicle mounted on a chassis dynamometer

This study investigated the performance and emissions of flex fuels in a 110-cc BS6-compliant fuel-injected two-wheeler without ethanol adaptation adjustments.The tests were carried out under controlled conditions on a chassis dynamometer at 1000,2000 and 3000 r.p.m.using ethanol blends from 10%ethanol(E10)to 85%ethanol(E85).Parameters examined included brake power(BP)output,brake-specific fuel consumption(BSFC),peak in-cylinder pressure and exhaust temperature.Emissions,including carbon monoxide(CO),hydrocarbons(HC),nitrogen oxide(NOx)and unregulated emissions,were also assessed.As the percentages of the ethanol blend increased from E10 to E85,there was a noticeable improvement in power output.At 1000 r.p.m.,the BP ranged from 2.4 to 4.6 kW for different blends.The BSFC and the peak in-cylinder pressure followed a similar pattern,indicating enhanced performance and fuel efficiency with higher ethanol concentrations.Interestingly,using E85 at 1000 r.p.m.resulted in a significant 41.08%reduction in exhaust temperature compared with E10,although this difference decreased with higher blend percentages.Furthermore,replacing E10 with E85 at 1000 r.p.m.reduced CO and HC emissions by 9.17%and 38.34%,respectively.In contrast,NOx emissions increased at all r.p.m.levels with higher-ethanol blends,peaking at a 415 parts per million increase at 3000 r.p.m.However,unregulated emissions decreased significantly with increased r.p.m.and ethanol content.In summary,the use of flex-fuel blends in a two-wheeler resulted in a modest increase in BP output,improved fuel efficiency and lower CO and HC emissions.These findings are vital for optimizing ethanol blend utilization in two-wheeler engines under low-load conditions,considering both performance and environmental aspects.

An upgraded Myxococcus xanthus chassis with enhanced growth characteristics for efficient genetic manipulation

Myxobacteria are well known for multicellular social behaviors and valued for biosynthesis of natural products.Myxobacteria social behaviors such as clumping growth severely hamper strain cultivation and genetic manip-ulation.Using Myxococcus xanthus DK1622,we engineered Hu04,which is deficient in multicellular behavior and pigmentation.Hu04,while maintaining nutritional growth and a similar metabolic background,exhibits improved dispersed growth,streamlining operational procedures.It achieves high cell densities in culture and is promising for synthetic biology applications.

A MoClo-Compatible Toolbox of ECF Sigma Factor-Based Regulatory Switches for Proteobacterial Chassis

The construction of complex synthetic gene circuits with predetermined and reliable output depends on orthogonal regulatory parts that do not inadvertently interfere with the host machinery or with other circuit components.Previously,extracytoplasmic function sigma factors(ECFs),a diverse group of alternative sigma factors with distinct promoter specificities,were shown to have great potential as context-independent regulators,but so far,they have only been used in a few model species.Here,we show that the alphaproteobacterium Sinorhizobium meliloti,which has been proposed as a plant-associated bacterial chassis for synthetic biology,has a similar phylogenetic ECF acceptance range as the gammaproteobacterium Escherichia coli.A common set of orthogonal ECF-based regulators that can be used in both bacterial hosts was identified and used to create 2-step delay circuits.The genetic circuits were implemented in single copy in E.coli by chromosomal integration using an established method that utilizes bacteriophage integrases.In S.meliloti,we demonstrated the usability of single-copy pABC plasmids as equivalent carriers of the synthetic circuits.The circuits were either implemented on a single pABC or modularly distributed on 3 such plasmids.In addition,we provide a toolbox containing pABC plasmids compatible with the Golden Gate(MoClo)cloning standard and a library of basic parts that enable the construction of ECF-based circuits in S.meliloti and in E.coli.This work contributes to building a context-independent and species-overarching ECF-based toolbox for synthetic biology applications.

Path Tracking Control for Autonomous Truck with Dual Modular Chassis

This study focuses on enhancing the agility and path tracking capabilities of autonomous trucks equipped with dual 4WIS-4WID modular chassis.To address the challenges associated with these versatile vehicles,a comprehensive approach is presented.Firstly,a communication framework is devised,utilizing a hierarchical combination of two fieldbus systems.This framework facilitates adaptive marshalling,allowing effective communication and coordination among the various modular components of the autonomous truck.Secondly,a reference path generation strategy is proposed.This strategy relates the motion paths of the truck's body to its modular chassis.Reference paths for the modular chassis are derived based on the center of mass,effectively resolving the issue of differing motion paths.To tackle the path tracking problem for dual modular chassis,a cooperative path tracking controller is developed.This controller is designed using the kinematic model of the autonomous truck,enabling adaptive control through online adjustments of controller parameters based on measured input–output data.Simulation and real vehicle testing validate the proposed path tracking controller.In the dual modular chassis path tracking simulation,the maximum lateral position error and the maximum yaw angle error of truck body at different speeds are 0.082 m and 0.007 rad,respectively.In the real vehicle test,the maximum lateral position error is 0.194 m,and the maximum yaw angle error is 0.071 rad.These results demonstrate the practicality and effectiveness of the controller in real-world applications.