A Comprehensive Vehicle and Tire Dynamics Simulation Model
VDANL (Vehicle Dynamics Analysis, Non Linear) is a comprehensive vehicle dynamics simulation program that runs under Windows 95/98/NT/2000 and is intended for the analysis of passenger cars, light trucks, articulated vehicles and multi-purpose vehicles. The simulation model is designed to permit analysis of virtually all driver induced maneuvering up through limit performance conditions defined by tire saturation characteristics, and includes driver feedback control features.
The Vehicle Model
Model equations cover the full range of lateral/directional and longitudinal motions up through large angles experienced in spin out and rollover. The vehicle model includes components for sprung and unsprung masses, suspension, steering, braking, power train, drive train, and tires. The model includes a comprehensive tire model and properly accounts for the effects of maneuver induced load transfer. The vehicle and tire models are based on past research and have been extensively validated.
- Tires - Tire characteristics play a dramatic role in vehicle dynamics since they respond to vehicle maneuvering. The tire model generates lateral and longitudinal tire forces and aligning moments as functions of normal load, slip and camber angle and includes appropriate interactions between these input variables including force saturation.
- Suspension - Composite suspension characteristics are designed to represent wheel steer and camber motions relative to the sprung mass and squat/lift forces resulting from tire ground plane forces acting on the suspension geometry. Wheel steer also arises from compliance in response to tire side force and aligning torque.
- Steering - Steering Model includes Ackerman steer effects and compliance, and a composite second order characteristic to simulate steering dynamics in response to steering and aligning torque inputs.
- Power and Drive Train - Power and drive train model includes engine, transmission, differentials and torque splitting between the front and rear axles. Front, rear and four-wheel-drive can be accommodated.
STI Tire Model Compared with Field Test Data - Brakes - Brake model includes simulation of vacuum boost run-out and a nonlinear proportioning valve between the front and rear axles. Also includes a generic ABS system. Truck brakes include trailer pneumatic lag and fade due to over heating.
Capabilities and Features
VDANL can be used in a variety of ways to analyze vehicle maneuvering motions, handling and stability. Input control commands (e.g. steering, braking, throttle, aerodynamic) can be applied directly to the open loop vehicle. Under driver model closed loop control the simulation can be excited with r oad curvature, lane position and speed commands. A large number of vehicle input and response variables can be saved to a file for subsequent analysis and/or plotted using time history and XY formats. An external Windows based plotting utility (WinEP by Mechanical Simulation Corporation, Ann Arbor, MI) is provided for data display and analysis.
Program control is achieved through a Windows? point and click interface. The program can also be controlled with command files containing sequences of program commands. Built in help features provide on-line display of the user's guide and technical reference.
 Strip Chart Plot of Sample VDANL Results |
 XY Plot of Sample VDANL results |
Applications Include
- Dynamic response and stability
- Low-g and limit performance handling
- Traction control and braking
- Suspension design and load transfer
- Closed loop driver/vehicle response problems
- Accident reconstruction
- Trailer Towing
Additional VDANL Features
- Common vehicle dynamics with the STISIM Drive® driving simulator. Vehicle models can be developed using VDANL, then run in the real-time, driver-in-the-loop simulator.
- A 3D terrain model allows a multi-lane roadway to be defined using simple commands. Horizontal and vertical curves can be defined along with roadway cross-slopes. Surface attributes can be assigned to portions of the roadway, which are recognized by the vehicle tire model, allowing changing tire/roadway characteristics based on position on the roadway. This 3D terrain is common with STISIMDrive™.
- Open Module option allows users to write code to be integrated into the VDANL simulation, enabling custom simulations to be created. Hardware-in-the-loop simulation is possible using the Open Module and STISIM Drive®.
- MATLAB? binary file output allowing post-processing and plotting within MATLAB.
Hardware Requirements
VDANL is designed to run on a PC with an Intel? Pentium class processor or compatible with Windows 95/98? or Windows NT/2000?.
Further Information
VDANL and the STI Tire Models Reference List
Narendran, D. B. Pape, J. A. Hadden, J H. Everson, and D. A. Pomerleau, "Analytical Methodology for Design and Performance Assessment of Run-Off-Road Collision Avoidance Systems, " SAE Paper 970455, 1997.
Chrstos, Jeffrey P., and Gary J. Heydinger, "Evaluation of VDANL and VDM RoAD for Predicting the Vehicle Dynamics of a 1994 Ford Taurus, " SAE Paper 970566, 1997.
Lee, Allan Y. and Alan T. Marriott, Nhan T. Le, "Variable Dynamic Testbed Vehicle: Dynamics Analysis, " SAE Paper 970560, 1997
Allen, R. Wade, Theodore J. Rosenthal, and Jeffrey P. Chrstos, "A Vehicle Dynamics Tire Model for Both Pavement and Off-Road Conditions," SAE 970559, 1997
Allen, R. Wade, Theodore J. Rosenthal, David H. Klyde, Fritz G. Anderson, Jeffery R. Hogue, and Jeffrey P. Chrstos, "A Vehicle Dynamics Model for Low Cost, PC Based Driving Simulations," Proceedings of the Third Driving Simulation Congress, ETNA, 242 Boulevard Voltaire 75011 Paris, July 1997.
Allen, R. Wade, T. J. Rosenthal, and J. R Hogue, "Modeling and Simulation of Driver/Vehicle Interaction, " SAE Paper 960177 presented at 1996 SAE International Congress & Exposition, Cobo Center, Detroit, MI, Feb. 1996, pp. 26-29.
Gruening, James, K. A. Williams, Kurt Hoffmeister, and J. E. Bernard, "Tire Force and Moment Processor, " SAE Paper 960182, 1996.
Allen, R. W., R. E. Magdaleno, T. J. Rosenthal, D. H. Klyde, and J. R. Hogue, "Tire Modeling Requirements for Vehicle Dynamics Simulation," SAE Paper No. 950312, presented at the 1995 SAE Inc., Jan. 1995.
Allen, R. W. and T. J. Rosenthal, " Requirements for Vehicle Dynamics Simulation Models, " SAE Paper No. 940175, presented at the International Congress and Exposition, Detroit, MI, Feb. 28 - Mar. 3, 1994.
Allen, R. W., and T. J. Rosenthal, "A Computer Simulation Analysis of Safety Critical Maneuvers for Assessing Ground Vehicle Dynamic Stability," Vehicle Dynamics and Simulation, SAE SP-950, 1993, pp. 1-16.
Bowman, E. J., and E. H. Law, "A Feasibility Study of an Automotive Slip Control Braking System, " Vehicle Dynamics and Simulation, SAE SP-950, 1993, pp. 17-43.
Clover, C. L., and J. E. Bernard, "The Influence of Lateral Load Transfer Distribution on Directional Response," Vehicle Dynamics and Simulation, SAE SP-950, 1993, pp. 45-51.
McGuire, M.K., and D. A. Guenther, "Longitudinal Suspension Compliance Modeling with ADAMS," Vehicle Dynamics and Simulation, SAE SP-950, 1993, pp. 53-66.
Heydinger, G.J., P. A. Grygier, and S. Lee, "Pulse Testing Techniques Applied to Vehicle Handling Dynamics, " Vehicle Dynamics and Simulation, SAE SP-950, 1993, pp. 117-131.
Vedamuthu, S., and E. H. Law, "An Investigation of the Pulse Steer Method for Determining Automobile Handling Qualities, " Vehicle Dynamics and Simulation,SAE SP-950, 1993, pp. 133-162.
Allen, R.W., T. J. Rosenthal, D. H. Klyde, K. J. Owens, and H. T. Szostak, "Validation of Ground Vehicle Computer Simulations Developed for Dynamics Stability Analysis, " Vehicle Dynamics and Rollover Propensity Research, SAE SP-909, 1992, pp. 59-78.
Garrott, W.R., and G. J. Heydinger, "An Investigation, via Simulation, of Vehicle Characteristics that Contribute to Steering Maneuver Induced Rollover," Vehicle Dynamics and Rollover Propensity Research, SAE SP-909, 1992, pp. 151-166.
Allen, R.W., H. T. Szostak, T. J. Rosenthal, D. H. Klyde, and K. J. Owens, "Characteristics Influencing Ground Vehicle Lateral/Directional Dynamic Stability," Vehicle Dynamics and Electronic Controlled Suspensions, SAE SP-861, 1991, pp. 23-48.
Chrstos, J.P., "A Simplified Method for the Measurement of Composite Suspension Parameters," Vehicle Dynamics and Electronic Controlled Suspensions, SAE SP-861, 1991, pp. 1-13.
Heydinger, G.J., W. R. Garrott, and J. P. Chrstos, "The Importance of Tire Lag on Simulated Transient Vehicle Response," Vehicle Dynamics and Electronic Controlled Suspensions, SAE SP-861. 1991, pp. 49-61.