Service Solution Success

Vehicle Dynamics Performance Development

   Although energy conservation and environmental protection have become the focus of global attention, customers’ pursuit of high-quality vehicle driving performance, whether traditional vehicles or new electric ones, will never change, and the application of Advanced Driver Assistance System (ADAS) is increasing. Demand from the market determines the direction of research and development of new models in the automotive industry, and the protagonist is the vehicle dynamics.

   From the conceptual stage until the mass production, TS dynamics engineering team helps domestic automobile enterprises to implement a set of positive development process in the development of the vehicle dynamic performance and vehicle chassis to improve vehicle control, comfort and braking performance, and achieve the optimum performance balance in the vehicle performance target definition, the subsystem target decomposition from the vehicle to vehicle suspension, chassis type selection and layout design, simulation driven vehicle integration and chassis design optimization, trial test, subjective and objective evaluation and adjustment etc. With profound engineering experience in the vehicle chassis performance development, through comprehensive simulation, test and subjective adjustment ability, TS dynamics engineering team will help domestic vehicle enterprises build the chassis forward development ability, the chassis platform and the modular development process, and create models and brands of high quality passenger vehicle.

   The engineering solutions TS-engineering provides to the development of vehicle dynamic performance and vehicle chassis include

§                      Development and matching of chassis subsystem

Ø                      the steering system

1)                      matching and adjustment of HPS/EPS

2)                      steering Handling performance

3)                      simulation analysis and adjustment

Ø                      the brake system

4)                      development and matching of the brake system

5)                      evaluation, analysis and optimization of braking performance and sense of pedal

6)                      simulation analysis of the steering system

§                      Development of chassis and vehicle dynamics performance Ride & Handling

Ø                      objective test and subjective evaluation

Ø                      benchmarking analysis and target definition

Ø                      target decomposition of chassis positive development

Ø                      CAE performance analysis and chassis optimization

Ø                      prototype trial

Ø                      chassis adjustment

§                      Chassis and vehicle integration

Ø                      matching of chassis, body and powertrain

Ø                      design optimization of vehicle body structure based on vehicle dynamics target

Ø                      Powertrain control

§                      Balance and optimization of vehicle multi- performance

Ø                      Ride & Handling

Ø                      Durability

Ø                      Road Noise/NVH

Ø                      Durability

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1 Performance development of handling stability and ride comfort

   As both handling stability and ride comfort have a direct effect on the driver and passengers in control and riding experience, more and more consumers are concerned about them in the car market. Vehicle manufacturers pay more attention to them in the development of new models, and put forward higher requirements for performance.

Good handling stability and riding comfort lie in the good matching and integration of assemblies or subsystems of tires, suspension, steering, body, and powertrain. Providing vehicle manufacturers with engineering services in vehicle R&H' performance target setting and decomposition, CAE analysis and optimization, and prototype debugging in all development stages, and helping AOEM customers to complete the overall optimization of the chassis and the vehicle integration scheme in the chassis development, according to the vehicle market positioning and development target, TS Engineering helps achieve the optimum balance between the contradictory indexes of control stability and ride comfort.

 

Target definition

                      VoC analysis

                      Objective test

                      Subjective evaluation

                      Benchmarking analysis

                      Vehicle target definition

Target decomposition

                      Target decomposition

                      Chassis general layout

                      Subsystem definition

                      Structural definition

                      Subsystem design

Engineering development

                      CAE analysis

                      Virtual tuning

                      Structural optimization

                      Multi-performance balance

                      Vehicle integration

Prototype production and debugging

                      Prototype production

                      Test verification

                      Evaluation diagnosis

                      Chassis tuning

                      Design finalisation

 

 

1.1 Target definition

§                      Target

Ø                      On the basis of market research to fully understand customer needs and product positioning, through the subjective and objective test on the competing and benchmarking vehicles (suspension K&C test, the vehicle handling stability test and vehicle ride comfort test), and analysis of customer demands and market positioning of the vehicle being developed, and the performance status of the benchmarking and competing vehicles the vehicle in the vehicle dynamics, the chassis development project target for the new model are formulated.

§                      Typical work

Ø                      Market researchVoC analysis and selection of benchmarking vehicle

Ø                      Benchmarking vehicle test

1)                      Suspension K&C test

2)                      Vehicle handling stability test (subjective & objective)

3)                      Vehicle ride comfort test (subjective & objective)

Ø                      Benchmark analysis of R&H performance of benchmarking vehicle

Ø                      Vehicle R&H performance engineering target setting

§                      TS engineering services and solutions

Ø                      Engineering services

1)                      Objective test and subjective evaluation of benchmarking vehicle K&C test and vehicle R&H performance

2)                      Data processing and synthesis of results of objective test and subjective evaluation

3)                      Consistency and correlation analysis between objective test and subjective evaluation

4)                      Performance benchmarking analysis and detailed interpretation

5)                      Subjective and objective target definition of vehicle R&H performance

6)                      Vehicle performance target decomposition to determine the performance objectives of each subsystem, including front and rear suspension, steering system, brake system, tires, power assembly and body

Ø                      Advantages and characteristics

1)                      A complete subjective and objective evaluation system for handling stability and ride performance

2)                      Consistency and correlation between subjective and objective evaluations

3)                      Target definition and decomposition

 

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Vertical runout of wheel

Wheel center shift

Change of wheel alignment parameter

Steering wheel angle input

Vertical stiffness change of suspension

Roll stiffness change of suspension

 Wheel three-directional forces

Roll center change of suspension

Static load variation between components

Wheel three-directional force torque

Directional system characteristics change

Anti-dive when braking, anti-squat when starting

 

The key of the vehicle dynamic performance target definition is full balance and self - consistency of the indexes such as handling stability, ride comfort and steering performance and can truly reflect customers’ voice, market positioning, competitive advantages and development target of the vehicle and meanwhile depends on engineering experience and data accumulation. With its complete subjective and objective performance evaluation system of handling stability and ride comfort and a set of methods to conduct benchmarking analysis and target definition and performance evaluation of competing or benchmarking vehicles, TS Engineering develops vehicle R&H performance targets and then decompose and specify them.

Ø                      Consistency analysis of subjective and objective R&H performance targets

Ø                      Analysis of the balance, compatibility and feasibility of R&H performance targets

Ø                      On the basis of the objective index decomposition of the one-dimension vehicle dynamics simulation, the performance target of each subsystem is determined.

Ø                      Optimization of vehicle integrated R & H performance based on subsystem performance

Ø                      DOE analysis of subsystem performance and formulation of the final subsystem performance objectives

1.2 Target decomposition

§                      Target

Ø                      In the conceptual design phase, the specifications of every subsystem such as suspension are define, so as to achieve the desired stability and peaceful performance.

Ø                      Target decomposition and chassis architecture definition in the conceptual design phase of the chassis

Ø                      According to the vehicle dynamics development target, it is decomposed into subsystems (tires, suspension, steering, braking, power assembly and body ).

Ø                      Selection of front and rear suspension architectures and definition and implementation of K&C characteristics

Ø                      Overall layout of the chassis, suspension layout and design, determination of the suspension structure and layout program

§                      Typical work

Ø                      Vehicle simulation analysis and parameter matching in the conceptual stage

Ø                      Selection of tire type

Ø                      Target definition of body structure characteristics

Ø                      Target definition of related powertrain characteristics

Ø                      Target decomposition of front and rear suspension and steering system

Ø                      Establish of suspension K&C characteristics

Ø                      Layout and geometric optimization of suspension architecture

§                      TS engineering services and solutions

Ø                      Engineering services

1)                      Target decomposition based on structured process approach and system level simulation analysis

2)                      Based on the limited known conditions and design constraints, the vehicle target is decomposed into subsystems and components

3)                      Suspension support design

4)                      Definition of suspension K&C characteristics

5)                      Adjustment and optimization of suspension hard spots

Ø                      Advantages and characteristics

1)                      A set of target decomposition approaches of structure and process has been established.

2)                      With a combination of engineering experience, system level simulation and multi-body dynamics simulation, fine tuning of K&C characteristics and geometric structure of suspension is conducted.

   With vehicle R&H performance target definition and decomposition technology, TS Engineering can further decompose R&H development target to the chassis system and components on the basis of the performance evaluation and target definition based on competitive or reference models. What’s more, we have established a complete set of methods and systems to decompose the engineering overall target to subsystems and components, interpret and verify chassis dynamics mechanism to conduct optimization of vehicle handling stability, ride comfort and steering performance in the conceptual design stage with only limited data available, through the one-dimension system simulation and three-dimension multi-body dynamics simulation tools and the use of effective simplified model.

 

 

 

CAE analysis and target definition

Suspension

Detailed engineering stage

Vehicle

Chassis general layout design

Suspension design

 

 

Target

Chassis general layout design support

Suspension K&C definition

Suspension design and optimization

Vehicle R&H performance optimization

Project settings

 

 

 

Method of CAE modeling

System level simulation model

Multi-body dynamic model (rigid-body)

Multi-body dynamic model (flexible body contained)

 

Analysis and optimization of suspension system

The suspension system is an important subsystem to ensure the vehicle handling stability and ride comfort. In the suspension development stage, the optimization of the suspension K&C characteristics can ensure the vehicle R&H characteristics. Meanwhile, to achieve the optimal suspension K&C characteristics, the structure design of the suspension and the design and optimization of the suspension elastic components are also the main tasks of the suspension design.

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TS Engineering helps customers fine tune the suspension design and provide the necessary design feedback in the of different suspension development stages, to ensure suspension and vehicle performance requirements:

§                      In the analysis stage of benchmark and reference vehicles,TS Engineering helps customers conduct the K&C test of benchmark and reference vehicles and give support to Benchmark analysis and target definition to formulate the target range of K&C characteristics of the vehicle model through the interpretation and analysis of K&Ck test results.

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§                      In the early stage of suspension development, through the target decomposition process and system level simulation analysis, the vehicle R&H performance indexes are decomposed to the suspension level, and the suspension K&C characteristics are defined. The K&C characteristics, absorber and suspension spring characteristics are optimized, with vehicle R&H performance taken into consideration.

 

Vehicle level

deficiency steering characteristic

System

level

analysis

model

Multi-body

dynamic

model

System level

Suspension/steering system characteristic

E.g wheel jumping characteristics, roll steering, lateral force steering

Inside and outside wheel steering curve

Front/rear suspension balance

Subsystem level

Chassis structure hard spots

Component level

Technical requirements for components

E.g cornering stiffness characteristics of tire, stiffness characteristics of bushing

 

 

 

§                      In the detail design stage of suspension, a detailed multi-body dynamics model of suspension system is established to ensure the suspension K&C performance indexes, and fine tuning of suspension design is carried out.TS Engineering can conduct sensitivity analysis and optimization tuning for customers in the following designs as follows,

Ø                      suspension hard spots

Ø                      structural design of steering system

Ø                      stiffness characteristics of chassis bushings

Ø                      suspension spring stiffness and absorber characteristics

Ø                      stiffness characteristics and clearance design of suspension cushion block

Ø                      Characteristics of lateral stabilizer bar

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1.3 Engineering development

§                      Target

Ø                      CAE analysis of vehicle R&H performance

Ø                      Based on the defined vehicle R&H performance target, detailed sensitivity analysis and optimization are made of the chassis ( front and rear suspension and steering system ) by the vehicle level model.

Ø                      Through simulation optimization, precise virtual debugging is made of the chassis design (hard spots, bushing, spring, absorber, lateral stabilizer bar, cushion block, travel and clearance, etc.)

Ø                      Before the prototype test, the chassis design is optimized to ensure the vehicle performance of the whole and lower the risk of trial production and adjustment.

§                      Typical work

Ø                      Vehicle CAE modeling and model refinement

Ø                      Vehicle dynamics analysis and correlation

Ø                      Parameter sensitivity analysis of front and rear suspension and steering system

Ø                      Adjustment and optimization of front and rear suspension and steering system

Ø                      Vehicle performance optimization

§                      TS engineering services and solutions

Ø                      Engineering services

1)                      CAE modeling of vehicle multi-body dynamics

2)                      Model debugging and benchmarking

3)                      Vehicle R&H performance analysis

4)                      Sensitivity analysis of chassis design parameters

5)                      Chassis design parameter optimization

6)                      Vehicle R&H performance optimization

Ø                      Advantages and characteristics

1)                      Rich experience of vehicle multi - body dynamic modeling, model debugging and fine tuning

2)                      Comprehensive optimization and balance of handling stability and ride comfort

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CAE analysis and optimization of vehicle R&H performance of

   In the whole vehicle engineering development stage, R&H performance prediction and optimization of CAE model can significantly reduce the dependence inf the prototype phase on subjective evaluation and subjective adjustment and the risk of subjective adjustment, and save time and cost.

   TS Engineering provides customers with high quality CAE analysis and optimization solution for R&H performance, and the chassis design feedback for you in the engineering development phase to ensure the R&H performance of the designed vehicle will achieve the desired objectives. The specific solutions are as follows,

§                      the establishment of vehicle dynamics model, including the model simplification method and model checking for each vehicle subsystem to ensure the accuracy of the vehicle model prediction results

§                      For the key input parameters that affect the performance of the vehicle prediction performance, TS Engineering provides test schemes and processing approaches of test results

§                      Vehicle R&H working condition simulation, evaluation index extraction, and a detailed evaluation report

§                      DOE analysis and optimization analysis of vehicle parameters based on R&H performance setting target

§                      Feedback for chassis development and design for R&H benchmarking analysis

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Multi-performance target optimization

In the chassis development, the balance between handling stability, ride comfort and other performances (NVH, such as noise) determines the strategy and direction of chassis tuning. However, it is difficult to tune these performances synthetically.

§                      the relationship between handling stability, ride comfort and road noise is conflicting.

Ø                      The handling stability usually requires that the suspension bushing has greater stiffness

Ø                      Ride comfort usually requires lower stiffness of the suspension bushing.

1)                      If the stability and ride performances are optimized separately, it will lead to inconsistencies and fail to meet the vehicle performance requirements.

2)                      Comprehensive multi-objective optimization of ride stability and ride comfort is required.

   TS Engineering can help customers with comprehensive balance and optimization of performances of Handling, Ride and others (e.g Road, Noise) on the basis of CAE in the early chassis design stages.

§                      Optimization objectives

Ø                      Improvement of handling stability while ensuring ride comfort, or,

Ø                      Improvement of ride comfort while ensuring handling stability, or,

Ø                      Synchronous improvement of handling stability and ride comfort

1)                      The priority depends on the current status of the vehicle, as well as market positioning and customer expectations

§                      Optimized output

Ø                      To achieve the desired balance between the handling stability and ride comfort

§                      Advantages and characteristics

Ø                      Rapid establishment of multi-body dynamics model of Ride & Handling analysis and NVH model of road noise analysis

Ø                      Evaluation index and priority definition of R&H performance and road noise performance

Ø                      Parameter sensitivity and optimization analysis technology

Ø                      Experience in comprehensive chassis performance tuning

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1.4 Test adjustment

§                      Target

Ø                      Prototype test

Ø                      Through the subjective evaluation and the subjective adjustment, the chassis design scheme is evaluated and adjusted to confirm the R&H performance target.

Ø                      Generally adjustable objects include spring, absorber, lateral stabilizer bar, bushing, tyre and steering system, etc.

§                      Typical work

Ø                      Objective test and subjective evaluation of vehicle R&H performance

Ø                       R&H performance tuning target definition

Ø                      Sample plan list, sample production and preparation

Ø                      Subjective evaluation and adjustment of test field ( mule vehicle and prototype)

Ø                      R&H performance target confirmation

Ø                      Release of debugging scheme

§                      TS engineering services and solutions

Ø                      Engineering services and advantages

1)                      Chinese and foreign chassis experts with deep tuning experience

2)                      A complete set of subjective and objective evaluation methods and system for R&H performance

3)                      "Turnkey" project of chassis R&H performance tuning

4)                      Comprehensive optimization and balance of handling stability, ride comfort and NVH performance

5)                      Through technology transfer, to help vehicle enterprises to train excellent engineers in chassis subjective adjustment

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Ø                      The main debugging content includes

1)                      Selection and adjustment of spring and stop blocks

2)                      Selection and adjustment of lateral stabilizer bar

3)                      Selection and adjustment of characteristic parameters of bush

4)                      Selection and adjustment of characteristic parameters for bushes and body suspension (subframe mounting)

5)                      Selection and adjustment of four - wheel alignment parameters

6)                      Selection and adjustment of steering system parameterSupplier on-site assistance is required);

7)                      Selection and adjustment of characteristic parameters of absorberSupplier on-site assistance is required

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Spring and absorber

tyre

elastic components:

buffer block

bush

 

Steering system

wheel alignment angle

 

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2 Brake system performance development

In general, the following aspects are paid close attention to in the development of brake system in vehicle enterprises.

§                      Braking regulations and efficiency

Ø                      Synchronous adhesion coefficient

Ø                      Braking efficiency and distance

Ø                      Regulatory requirements for vehicles matched with ABS system

§                      Brake pedal sense

Ø                      Braking sense at slight speed reduction

Ø                      Braking sense at medium speed reduction

Ø                      Braking sense at great speed reduction

Ø                      ABS working sense ( noise, feel of foot being pushed )

§                      Hot recession of braking system

Ø                      Temperature change during braking

Ø                      Variation characteristics of braking efficiency in high strength braking or continuous braking

Ø                      Brake thermal deformation

Ø                      Effect of heat - structural coupling on the durability of components

§                      Stiffness strength analysis of brake system components

Ø                      Influence of high strength braking load on the strength and durability of components

§                      Brake NVH problems

Ø                      Low, medium and high frequency noise when braking

Ø                      Steering wheel vibration caused by braking, (Brake Judder) and so on

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Having extensive engineering experience in the brake system development, our solutions and engineering services will enhance your confidence in the development of the brake system and fully improve its performance.

 

 

2.1 Design matching and regulation analysis of braking system

   TS has a complete set of its own system of the brake system design matching and brake regulation analysis methods.

§                      Braking regulations

Ø                      The analysis of brake regulations is mainly aimed at vehicles without ABS, to prevent the rear wheel from first block in the braking process.

Ø                      Generally, the braking force distribution ratio between the front and rear brakes is designed to meet the brake regulations through reasonable design

Ø                      TS has the self-developed tool to design the braking system to meet the brake regulations.

 

 

Vehicle type

Braking force distribution ratio

Braking efficiency with wheels unlocked

general vehicle

fixed

worst

Vehicle with proportional valve

One regulation

general

Vehicle with load sensing proportional valve

Change with load variation, but not with road conditions

better

Vehicle with ABS

Real-time change with load variation,and road conditions

best

 

§                      Prediction of braking distance

Ø                      TS has accurate prediction and design capabilities of braking distance.

Ø                      Based on the brake system theory and lots of database and experience, at the same time with the brake system CAE model ( one-dimension physical system model of Simulink )

Ø                      Theoretical guidance and database support are made full use of in the prediction of braking distance , while the actual conditions taken into full account (such as test methods)

 

 

2.2 Evaluation and optimization of pedal sense

The brake pedal sense is the comprehensive braking feel that the driver feels through braking force, braking deceleration and brake pedal travel during the braking process. A good brake pedal sense can give the driver confidence and provide comfortable braking experience.TS has rich engineering experience in subjective evaluation, simulation analysis and design optimization of brake pedal sense.

§                      Brake pedal sense evaluation

Ø                      Subjective evaluation

1)                      Idle stroke

2)                      Pedal force required small deceleration

3)                      Linearity of pedal force at all stages

4)                      Pedal rigidity (travel- force relationship)

5)                      Confidence given to people at great deceleration

6)                      Inflection point at great deceleration, etc.

Ø                      Objective Test

Ø                      Target definition of brake pedal sense

Ø                      Enterprise standard definition of brake pedal sense

§                      Analysis and optimization of brake pedal sense

Ø                      CAE model library of the various verified parts of the brake system

Ø                      Prediction of pedal sense on CAE model,and analysis of influence of braking system parameters on pedal sense

Ø                      Optimization of brake pedal sense

Ø                      Special platforms for brake system regulations and pedal sense analysis

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Subjective evaluation of brake performance

Objective teat of brake performance

Determination of the brake pedal sense target value

Vehicle brake system modeling

Design constraints for brake system

Reference vehicle plan for reference

cost

General layout

Product maturity

Target decomposition of brake performance

 

 

Scheme satisfying requirements

Optimization scheme

 

Design completion

 

 

 

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2.3 Brake thermal analysis

The main purpose of brake thermal analysis, which is based mainly on the finite element method, is to predict the temperature change during braking by means of CAE, so as to further predict the change of braking efficiency and brake thermal deterioration.

Temperature Chart of Hollow Disc Brake (simulation)

Comparison of Test and Simulation Results

 

2.4 Stiffness and strength analysis of brake system components

With CAE multi-body dynamics and finite element analysis, the strength and durability of the braking system components can be predicted, so as to guide the structure design of the brake system components ( calliper, back plate, knuckle, etc. ) and even suspension.

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Brake Pedal Stiffness Analysis

 

2.5 Analysis of braking NVH performance

Common NVH problems in the brake system include brake noise and jitter.

§                      Brake noise

The occurrence conditions of brake noise are complicated and it is caused by the vibration of the brake itself. In fact, the occurrence and research of squeal are more, whose frequency range is 1-16kHz.

When encountering brake noise problems, you can ask TS Engineering for help. Through effective CAE analysis and test, understanding of noise mechanism and origin, and analysis of the influence of structural parameters on noise, we can help you further improve your structure schemes .

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§                      Brake judder

Brake judder is mainly the dynamic vibration of chassis system caused by the fluctuation of wheel braking torque in the vehicle braking, with a frequency of 10 - 25 Hz.

It often presents itself as follows,

Ø                      brake pedal jitter

Ø                      steering wheel torsional vibration

Ø                      seat vibration

Ø                      vehicle floor vibration

TS Engineering will help you solve the problem of brake judder in the following aspects,

Ø                      Starting from eliminating vibration source and improving the quality of the brake system, to eliminate or weaken the brake torque vibration phenomenon.

Ø                      Optimizing the vibration transmission path to suppress the vibration intensity transmitted to the steering system and body, for example,

1)                      Adjustment of the suspension parameters and optimization of the suspension system modality

2)                      Optimization of local or overall structural stiffness of vehicle body

3)                      Adding the energy absorption device to the steering system

Ø                      The system characteristics are studied and analyzed with CAE analysis and test, to find the optimum solution.

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Engineering service

Vehicle Dynamics Performance Development