VI-Motorcycle Capabilities VI-Motorcycle is an engineering environ-ment for the simulation of high perfor-mance and production motorcycles and scooters.

• The Subsystem Architecture separates complex tasks and provides an intuitive interface.

• The Template Builder helps to build new designs quickly and efficiently.

• The Data Libraries assure com-ponent standardization and allow easy data management.

• The Road Builder simplifies defi-nition of any type of 2D or 3D road profile.

• The System Level Approach helps the understanding of vehicle performance by cross-correlating all individual components.

• Modelling within the VI-Motorcycle environment provides full support of several specialized modules for FEA, Hydraulics, Control Systems and other con-current disciplines.

• The Simulation Menu allows for various types of maneuvers for complete virtual testing of the motorcycle model.

• The Plotting environment offers a convenient method for review-ing results.

The motorcycle can be driven on a two or three dimensional track profile by a sophisti-cated driving program that pushes the bike to its limit. Simulating the bike at its limit in a reproducible manner allows engineers to opti-mize the vehicle performance without endan-gering and relying on the driver, thus making the process more objective. In addition to testing the model on a virtual track, there are several other rigs available to test components such as tires, subsystems such as the suspension, or the entire motorcy-cle on a two post rig. The flexible usage of the models is possible because of the modular architecture of VI-Motorcycle, which provides for very efficient model exchange and man-agement. In order to consider the effects of component flexibility it is possible to include flexible bodies generated with FEA codes.

Benefits With VI-Motorcycle it is possible to make design decisions in the shortest possible time at minimum cost, allowing you to:

• Beat the competition by finding the optimal set-up and advancing your technology faster.

• Save Time in the testing process by shifting tests into the virtual world before getting to the track or in the lab.

• Cut cost by reducing the number of prototypes.

• Improve stability and safety.

With the use of VI-Motorcycle, the specialized dynamic simulation environment for motor-cycle design and testing, an engineering team can quickly build and simulate a complete parameterized motorcycle model and select fundamental design options. Additionally, existing designs can be refined and production problems solved early in the development process, prior to building physical prototypes. By using a virtual rider, you can also mini-mize the risk in the testing process and increase the precision. Your testing process be-cause more effective, allowing more focus on design refinement.

VI-Motorcycle enables common modeling and design-methods throughout corporations and suppliers for ride, handling, stability and durability. In addition, VI-Motorcycle can be quickly adapted to your develop-ment process, since it is build upon an extendable and customizable architecture. Well beyond existing inter-faces to import CAD data, VI-Motorcycle allows you to create complete interfaces to your existing in-house tools. Because the software results have been proven out in many projects, users can be confident their motorcycle

and its subsystems will function properly when they actually do build and test their first hardware prototypes. Based on the renowned MSC ADAMS technology, VI-Motorcycle is continuously enhanced and validated by VI grade’s technical team, which stands ready to support you with services ranging from hotline to funded development programs.

Template Files

Course Data File

Suspensions

Frame Brakes

...

Component Data Files

Dampers

Bushings

Tires

Engine Map

Springs

MO

TO

RC

YC

LE

Motorcycle+Road+Driver System

RO

AD

DA

-

2D or 3D profile

Driver path

Racing Line Max Xls

System & Analysis Configuration

Tire Testrig Suspension Testrig

Steering Pad Step Steer

Double Lane Data Driven

CO

NF

IGU

RA

TIO

N

VI-MotorCycle/

Model Chains

Simulation In VI-Motorcycle you replicate your real world tests, which you usually conduct in a costly hardware based environment. The tests are conducted in the following disciplines: Stability • Impulsive steering torque

• Instant braking

• Steering bar release

• Hands off event in all driving conditions

• Weave & Wobble Modes Analysis (shown below)

• Stability procedure / stability indexes

Handling and agility • Straight line acceleration and braking

• General path trajectory following:

• applied to standard handling maneuvers such as lane change or j-turn.

• parametric transition curve section for continuity in the lat-eral acceleration diagram

• corner cutting and curvature minimization

• Constant radius cornering with vertical disturbance:

• parametric vertical profile height change on the track width

• analyse effects of vertical/longitudinal disturbance on vehi-cle stability, in both closed or open loops

• 2D or 3D (long wave) road

• Running full laps to optimize performance (shown below)

Durability Besides accurately predicting the motion of the bike, VI-Motorcycle provides loads and strain at any location in the system. Obtain data from critical locations that would be difficult to meas-ure in the real world, without making assumptions about the load transfer path. Being able to include flexible representations of some components such as the fork or the frame not only allows more accurate prediction of the stability of the motorcycle, but also allows direct loads and stress calculations within VI-Motorcycle. You may include flexible components from any of the popular FEA packages. The image on the right shows an example, which includes flexible bodies for the front fork, the frame and the swing arm. Stress time histories, which can be used for fatigue life assessment, are com-puted automatically on the fly.

Rider One of the key advantages of using VI-Motorcycle is the advanced rider model, which can function as an open or closed loop control-ler. The rider can direct any of the maneuvers, including following any 2D or 3D road profile.

First, a maneuver is defined using the model, road data, and some user input describing the rider characteristic such as preview time, all as inputs to the Task Planner. Next, the Trajectory Planner uses a reference model to calculate a state trajectory over the reference path and speed profile. Finally, the position of the de-tailed model is projected on the previously computed trajectory in order to calculate the control action to bring the detailed bike state over the reference state, taking into account the dynamic feasibil-ity of the control maneuver. The rider controls the steering, gear, throttle, and brake actuation channels and is even robust enough to deal with a sliding condi-tion.

3D Road and Path The road profiles are generated with the Road Builder in VI-Motorcycle. There are a number of predefined tracks and road sections available in the database delivered with the product. To create your own road you can assemble a complete profile with different sections based on measured data or analytical descrip-tions. You can drive the bike on:

• Race tracks

• Thru chicanes

• Flat and uneven roads

The optimal path for the bike to follow is generated automatically based on the 3D road profile. Taking the bike to the limit and assessing the performance means

that you need accurate tire models. One practical challenge in accurate tire simulation is not so much the mathematical model but the identification of the tire model parameters. VI-Motorcycle can be used for this as well. By following standard test procedures in the real world and replicating them in the virtual world using the virtual tire testrig in VI-Motorcycle, you can identify the parameters for your model. The testrig allows you to conduct the following tests:

• Lateral slip variation

• Longitudinal slip variation

• Combined (Constant Longitudinal Slip)

• Cornering Input

• Free Input

The automatic postprocessing generates all required plots. The plot below shows the lateral force variation with lateral slip angle for a lateral slip variation test.

Tire Testrig

Tires The tire is one of the key components of the motorcycle as it repre-sents the interface between the road and the bike. VI-grade offers virtual tire solutions with the following characteristics:

• Lateral force as function of slip angle, roll angle and vertical load

• Longitudinal force as function of longitudinal slip and vertical load

• Auto aligning torque as function of lateral slip and vertical load

• Combined slip mode

• Relaxation Length (time lag for tire response on impulse input)

• Contact point geometry as func-tion of roll angle and vertical load point, which is essential for cor-rectly capturing the rolling radius variation and the overturning mo-ment effect

Two Post Analysis With VI-Motorcycle, your bike can also be virtually tested on a two post rig just as if you would run a physical test in the lab. In this way, loads can be deter-mined or parameters rele-vant for comfort and stability can be compared. Standard tests include:

• Heave mode analysis

• Pitch mode analysis

• General vertical motion input

To learn more about our products and services please contact: Worldwide Web: www.vi-grade.com

Germany: VI-grade GmbH Zum Rosenmorgen 1-A D-35043 Marburg Germany Tel: +49 6421 30 92 18 E-mail: info@vi-grade.com

Italy: VI-grade srl Via L'Aquila 1c I-33010 Tavagnacco (UD) Italy Tel: +39 0432 68 91 51 E-mail: info@vi-grade.com

USA: VI-grade LLC 7648 Beebalm Court Dexter, MI 48130 USA Tel: +1 734 42 42 040 E-mail: info_us@vi-grade.com

Japan: VI-grade Japan 3-7-1Shinjuku Tochi Tatemono No.10 Bldg. 6F, 3-9-1, Shinjuku, Shinju-ku, Tokyo 1600022 Tel.:+ 81 3 6457 8503 E-mail: info_japan@vi-grade.com

In the case shown in the picture below an off-road bike was simulated to identify problems with suspension in terms of com-fort.

Application Examples

In the dynamics of the motorcycle–rider system, the rider has an important effect, which is influ-enced by:

• Rider mass (from 1/3 to 1/2 of the total)

• Rider capability to dynami-cally alter the position of the center of mass location of the entire system

• Rider flexibility due to joints and muscles

Often the rider is taken into account by attaching a rigid body with mass and inertia properties to the bike. Sometimes, more accurate results are required and a more realistic model of the human body including its joints and muscles is needed. When considering the vertical loads, the rider acts as a damped sys-tem and influences the overall dynamics significantly. With VI-Motorcycle, you can take advantage of the human body model and anthropometric database that comes with LifeMODTM of-fered by The Biomechanics Research Group, Inc.

A low damping in the front suspension causes the “pumping effect” that makes this scooter uncontrollable. VI-Motorcycle allows investigation of this effect and automatically produces the required output to assess the stability.

Human Rider

Engine and Drivetrain The engine is modeled with rigid bodies in VI-Motorcycle, which currently con-sider the rotating part inertia. Torque is produced as a function of RPM and throttle position, which is controlled by the rider model. The drivetrain includes a conceptual clutch, a gear box and a simple chain model that induces the appropriate pulling effects.

By defining an uneven road, the user can generally induce real-istic excitations into the system for comfort or durability studies. In the example below, the smooth 3D road was refined with PSD road data. Similarly, deterministic disturbances can be added. The upper plot shows the tire forces. The lower plot shows ve-

locity and roll angle as well as some driver demands: throttle and brake. The maneuver was a lane change like event.

The controller is not always responsible for instabilities …