Performance analysis of air suspension system of heavy truck with semi-active fuzzy control

In order to analyze and evaluate the performance of the air suspension system of heavy trucks with semi-active fuzzy control, a three-dimensional nonlinear dynamical model of a typical heavy truck with 16-DOF（degree of freedom） is established based on Matlab/Simulink software. The weighted root-mean-square（RMS） acceleration responses of the vertical driver ＇s seat, the pitch and roll angle of the cab, and the dynamic load coefficient（DLC） are chosen as objective functions, and the air suspension system is optimized and analyzed by the semi-active fuzzy control algorithm when vehicles operate under different operation conditions. The results show that the influence of the roll angle of the cab on the heavy truck ride comfort is clear when vehicles move on the road surface conditions of the ISO level D and ISO level E at a velocity over 27.5 m/s. The weighted RMS acceleration responses of vertical driver＇ s seat, the pitch and roll angle of the cab are decreased by 24%, 30% and 25%, respectively,when vehicles move on the road surface condition of the ISO level B at a velocity of 20 m/s. The value of the DLC also significantly decreases when vehicles operate under different operation conditions. Particularly, the DLC value of the tractor driver axle is greatly reduced by 27.4% when the vehicle operates under a vehicle fully-loaded condition on the road surface condition of ISO level B at a velocity of 27.5 m/s.

Nonlinear dynamic analysis of interaction between vehicle and road surfaces for 5-axle heavy truck

Based on the analysis of nonlinear geometric characteristics of the suspension systems and tires, a 3D nonlinear dynamic model of a typical heavy truck is established. The impact factors of dynamic tire loads, including the dynamic load stress factors, and the maximal and the minimal vertical dynamic load factors, are used to evaluate the dynamic interaction between heavy vehicles and roads under the condition of random road surface roughness. Matlab/Simulink is used to simulate the nonlinear dynamic system and calculate the impact factors. The effects of different road surface conditions on the safety of vehicle movement and the durability of parts of a vehicle are analyzed, as well as the effects of different structural parameters and different vehicle speeds on road surfaces. The study results provide both the warning limits of road surface roughness and the limits of corresponding dynamic parameters for the 5-axle heavy truck.

Comparison of two suspension control strategies for multi-axle heavy truck

Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (MSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototype (FVP) model and compared in terms of road friendliness and ride comfort. A four-axle heavy truck-road coupling system model was established using FVP technology and validated through a ride comfort test. Then appropriate passive air suspensions were chosen to replace the rear tandem suspensions of the original truck model for preliminary optimization. The mechanical properties and time lag of dampers were taken into account in simulations of MSD and PID semi-active dampers implemented using MATLAB/Simulink. Through co-simulations with Adams and MATLAB, the effects of semi-active MSD and PID control were analyzed and compared, and control parameters which afforded the best comprehensive performance for each control strategy were chosen. Simulation results indicate that compared with the passive air suspension truck, semi-active MSD control improves both ride comfort and road-friendliness markedly, with optimization ratios of RMS vertical acceleration and RMS tyre force ranging from 10.1% to 44.8%. However, semi-active PID control only reduces vertical vibration of the driver's seat by 11.1%, 11.1% and 10.9% on A, B and C level roads respectively. Both strategies are robust to the variation of road level.

Rollover Prevention and Motion Planning for an Intelligent Heavy Truck

It is very necessary for an intelligent heavy truck to have the ability to prevent rollover independently.However,it was rarely considered in intelligent vehicle motion planning.To improve rollover stability,a motion planning strategy with autonomous anti rollover ability for an intelligent heavy truck is put forward in this paper.Considering the influence of unsprung mass in the front axle and the rear axle and the body roll stiffness on vehicle rollover stability,a rollover dynamics model is built for the intelligent heavy truck.From the model,a novel rollover index is derived to evaluate vehicle rollover risk accurately,and a model predictive control algorithm is applicated to design the motion planning strategy for the intelligent heavy truck,which integrates the vehicle rollover stability,the artificial potential field for the obstacle avoidance,the path tracking and vehicle dynamics constrains.Then,the optimal path is obtained to meet the requirements that the intelligent heavy truck can avoid obstacles and drive stably without rollover.In addition,three typical scenarios are designed to numerically simulate the dynamic performance of the intelligent heavy truck.The results show that the proposed motion planning strategy can avoid collisions and improve vehicle rollover stability effectively even under the worst driving scenarios.

Active Noise Control of the Heavy Truck Interior Cab

In order to control the noise of the heavy truck interior cab effectively, the active noise control methods are employed. First, an interior noise field test for the heavy truck is performed, and frequencies of interior noise of this vehicle are analyzed. According to the spectrum analysis of acquired noise signal, it is found out that the main frequencies of interior noise are less than 800Hz. Then the least squares lattice （LSL） algorithm is used as signal processing algorithm of the controller and a closed-loop control DSP system, based on TMS 320VC5416, is developed. The residual signal at driver＇s ear is used as feedback signal. Lastly, the developed ANC system is loaded into the heavy truck cab, and controlling the noise at driver＇ s ear for that truck at different driving speeds is attempted. The noise control test results indicate that the cab interior noise is reduced averagely by 0.9 dBA at different driving speeds.

Numerical simulation of dynamic response of subgrade under moving heavy truck in cold regions

This paper reports on the dynamic response of highway subgmde under moving heavy Wuck in cold regions. Numerical simulations are performed in two stages. In the first stage, the moving heavy truck vibration, induced by mad roughness, is calculated through a three-dimensional dynamic interaction model of heavy tmckavement-subgrade, and the lime-histories of nodal loads on the top of the base are calculated through this model. In the second stage, a two-dimensional dynamic finite element model of the bgrade-ground system is formulated, using the calculated nodal loads from the first stage as input. The dynamic resporkse of the subgrade is validated by field measurements, and the effects of mack type, axle loading, running speed, and road roughness on the vertical dynamic slress in the unfrozen period and the spring thawing period are analyzed and discussed.

Dynamic response of precast segmental bridge columns under heavy truck impact

Considering the wide application of precast segmental bridge columns(PSBCs)in engineering practice,impact-resistant performance has gained significant attention.However,few studies have focused on PSBCs subjected to high-energy impacts caused by heavy truck collisions.Therefore,the behavior of PSBCs under a heavy truck impact was investigated in this study using high-fidelity finite element(FE)models.The detailed FE modeling methods of the PSBCs and heavy trucks were validated against experimental tests.The validated modeling methods were employed to simulate collisions between PSBCs and heavy trucks.The simulation results demonstrated that the engine and cargo caused two major peak impact forces during collision.Subsequently,the impact force,failure mode,displacement,and internal force of the PSBCs under heavy truck impacts were scrutinized.An extensive study was performed to assess the influence of the section size,truck weight,impact velocity,and number of precast segments on the impact responses.The truck weight was found to have a minor effect on the engine impact force.Damage was found to be localized at the bottom of the three segments,with the top remaining primarily undamaged.This parametric study demonstrated that larger cross-sections may be a preferred option to protect PSBCs against the impact of heavy trucks.

Analysis of coast-by noise of heavy truck tires

Heavy truck tires are one of ihe rnam sources of road traffic noise. However, the mecha- nism and plopagation of the noise generated by these tires have not been systematically investigated 7o determine the noise of heavy truck tires with different structures and patterns, and to analyze the coraelation between the indoor tire noise and coast-by tire noise, an integrated tire indoor noise test and a coast-by noise test were designed and successfully implemented. The indoor test was conducted on a drum inside a semi- anechoic chamber to simultaneously measure the near field and far field noise of the tires. The outdoor measurements were carried out using a coast-by test on the new ISO 10844 surface. A formula for quantitative analysis with appropriate corrections was developed to analyze the data with reasonable errors, which can be used to predict the coast-by noise through the indool tire noise test accurately and effectively. The analysis shows that when trying to build the relationship between indoor and outdoor heavy truck tire noise, care should be taken to differentiate the tires with a load capacity index in excess of 121 and without any dual fitting indication from ordinary tires, due to the specified test procedure.

Strategic Issues For Prospering China Heavy Truck Industry

As an important segment in auto industry, heavy duty truck industry plays a special strategy role in the national economy and social development. With the continuous, fast and healthy development of the national economy, the importance ofheavy duty truck has become more and more tangible. 1. The improvement of highway conditions and the construction of expressway will promote the adjustment of national transportation structure. Highway transportation trends towards long

The Up-rising of the Inner Mongolia's Heavy Truck Base

During the "8th Five-Year Plan" of China, Baotou North Heavy Truck Limited Liability Company and Baotou North-Benz Heavy Truck Limited Liability Company growing out of two big military plants——No. 1 Machinery Plant and the No. 2 Machinery Plant were founded. They introduced the technologies and

Probabilistic Lane-Change Decision-Making and Planning for Autonomous Heavy Vehicles

To improve the safety and driving stability of the autonomous heavy truck, it is necessary to consider the differences of driving behavior and drivable trajectories between the heavy trucks and passenger cars. This study proposes a probabilistic decision-making and trajectory planning framework for the autonomous heavy trucks. Firstly, the driving decision process is divided into intention generation and feasibility evaluations, which are realized using the utility theory and risk assessment, respectively. Subsequently the driving decision is made and sent to the trajectory planning module. In order to reflect the greater risks of the truck to other surrounding vehicles, the aggressiveness index(AI) is proposed and quantified to infer the asymmetrical risk level of lane-change maneuver. In the planning stage, the lateral and roll dynamics stability domains are developed as the constraints to exclude the candidate trajectories that would cause vehicle instability. Finally, the simulation results are compared between the proposed model and the artificial potential filed model in the scenarios extracted from the naturalistic driving data. It is shown that the proposed framework can provide the human-like lane-change decisions and truck-friendly trajectories, and performs well in dynamic driving environments.

Investigation of the optimum differential gear ratio for real driving cycles by experiment design and genetic algorithm

Experiment statistical method and genetic algorithms based optimization method are used to obtain the optimum differential gear ratio for heavy truck that provides best fuel consumption when changing the working condition that affects its torque and speed range. The aim of the study is to obtain the optimum differential gear ratio with fast and accurate optimization calculation without affecting drivability characteristics of the vehicle according to certain driving cycles that represent the new working conditions of the truck. The study is carried on a mining dump truck YT3621 with 9 for- ward shift manual transmission. Two loading conditions, no load and 40 t, and four on road real driving cycles have been discussed. The truck powertrain is modeled using GT-drive, and DOE -post processing tool of the GT-suite is used for DOE analysis and genetic algorithm optimization.

Research on the technical scheme of multi-stack common rail fuel cell engine based on the demand of commercial vehicle

At present,most fuel cell engines are single-stack systems,and high-power single-stack systems have bottlenecks in meeting the power requirements of heavy-duty trucks,mainly because the increase in the single active area and the excessive number of cells will lead to poor distribution uniformity of water,gas and heat in the stack,which will cause local attenuation and reduce the performance of the stack.This paper introduces the design concept of internal combustion engine,takes three-stack fuel cell engine as an example,designs multi-stack fuel cell system scheme and serialized high-voltage scheme.Through Intelligent control technology of independent hydrogen injection based on multi-stack coupling,the hydrogen injection inflow of each stack is controlled online according to the real-time anode pressure to achieve accurate fuel injection of a single stack and ensure the consistency between multiple stacks.proves the performance advantage of multi-stack fuel cell engine through theoretical design,intelligent control and test verification,and focuses on analyzing the key technical problems that may exist in multi-stack consistency.The research results provide a reference for the design of multi-stack fuel cell engines,and have important reference value for the powertrain design of long-distance heavy-duty and high-power fuel cell trucks.