EDSVS Engineering Dynamics Single Vehicle Simulation

EDSVS™ is a simulation of the response of a motor vehicle to driver throttle, braking and steering inputs. It is based on a program called TBST, developed at the University of Michigan Transportation Research Institute. As a simulation, the user provides a set of initial conditions and a table of driver inputs. EDSVS determines how the vehicle responds to inputs by generating the path, velocity, acceleration, tire forces and other data as a function of time. The path of the vehicle is also visually displayed on a scaled crash site diagram.

EDSVS is a 3-degree of freedom (yaw plane) analysis; suspension jounce/rebound is ignored. Suspension effects are modeled using the vehicle’s roll couple distribution. Longitudinal and lateral load transfers are calculated on a quasi-static basis. The program is particularly well suited to low-to-moderate road friction regimes. It also serves as an excellent first-order approximation for higher friction regimes.

EDSVS has a robust tire model that includes static and dynamic friction and the Fiala tire model. EDSVS also allows the user to model dual tires and tandem axles with inter-tandem load transfer.

Accident investigators can use EDSVS to determine how a driver may have lost vehicular control. Through adjustments of the vehicle’s throttle, braking and/or steering input values, the user will converge on those driver inputs that match crash site evidence. EDSVS can also be used to study the handling effects due to changes in vehicle weight distribution, wheelbase, track width, CG height, tire friction and cornering stiffness, payload weight and location and other parameters.

EDSVS has been extended and refined since its introduction in 1984. The program has a history of successful application in many types of vehicle dynamics problems. Validation studies are published in the technical literature.

If you would like to see an example of how to use EDSVS, download the Tutorial from the EDSVS Physics Manual. (Download time for this 1.1 MB Adobe PDF file is about 1 - 5 minutes, depending upon your connection speed.)

Input

Vehicle

• Selectable from HVE-2D’s built-in databases, according to Type (Passenger Car, Pickup, Sport-Utility, Van, Truck), Make, Model, Year, Body Style.
• Several Vehicle Database Sources (Generic, EDVDB™, User and others).
• All parameters are user-editable.

Environment

• Work directly on a scaled crash site diagram.
• User-definable friction zones such as asphalt, gravel, grass, standing water, oil spill . . .
• Local Gravitational Constant.

Event

• Drag-and-drop positioning of vehicles in the environment.
• Open-loop driver control tables (throttle, braking and steering).
• Simulation Controls (integration timesteps, convergence criterion, termination velocities, maximum simulation time, output time interval).
• Payload Data (location, weight, yaw inertia).

Output

Variable Output

• Vehicle Kinematics (position, velocity, acceleration vs. time).
• Tire Data (contact patch coordinates, forces, slip angle, skid status vs. time).
• Wheel Data (coordinates, steer angle vs. time).
• Driver Data (steering wheel angle vs. time).

Trajectory Simulation

• Visualization of vehicle motion on the crash site diagram at user-specified time intervals.

Reports

• Accident History (initial and final/rest positions and velocities).
• Driver Controls (throttle, braking and steering).
• Simulation Controls (numerical integration parameters).
• Vehicle Data (dimensions, inertias, tire properties).
• Messages (event related diagnostics).