HVE White Papers
||EDVDS (Engineering Dynamics Vehicle Dynamics Simulator)
||EDVDS is an HVE-compatible 3-D simulation of the dynamic response of a commercial vehicle to driver inputs and 3-D road conditions. A tow vehicle and up to three trailers may be simulated. EDVDS is an extended version of the Phase 4 program developed at the University of Michigan. Extensions include full 3-dimensional simulation capability, an updated suspension model with jounce/rebound stops, an updated tire model that supports 360° slip angles and 2-step radial tire stiffness, and the ability of each tire to respond to an arbitrary 3-D terrain. These advancements extend the capabilities of researchers to study real world highway safety issues involving commercial vehicles.
The user enters initial position, velocity and driver controls (steering, braking, throttle) for the tow vehicle. Trailers and dollys are automatically positioned according to connection locations. An optional payload may be assigned for the tow vehicle and each trailer. EDVDS then predicts the motion of each vehicle's sprung mass (X, Y, Z, roll, pitch, yaw), the motions of the unsprung masses (wheel deflections, spin velocities), suspension dynamics (spring forces and deflections, axle accelerations), tire dynamics (forces, moments and slip angles at the tire/road interface), and current brake system parameters at each wheel (air pressure, brake torque, lining temperature).
Vehicle design engineers and safety researchers can use EDVDS to perform detailed studies involving vehicle handling and controllability. Typical human factors issues include driver inputs and speed; vehicle factors include brake system and suspension design, loading conditions, and tire properties; and environment factors include superelevation and slippery road conditions.
EDVDS employs full 3-dimensional engineering models with up to 23 degrees-of-freedom for each vehicle. The program supports up to 4 axles per vehicle, solid and tandem axle suspension-types with inter-tandem load transfer, and single and dual tires. Combination vehicles are connected using fixed and converter dollys with rigid or hinged drawbars.
The small angle assumption in the Phase 4 program has been eliminated in EDVDS, allowing for simulation of complex roll-over events. In addition, EDVDS has been extended to include a comprehensive drivetrain model with engine performance parameters, multi-gear transmissions and differentials.
Tire vs terrain interaction is modeled transparently to the user. This powerful capability allows the user to create a detailed, 3-D environment (using HVE's 3-D Editor or any popular modeling package), then drive a vehicle on it. At each timestep, the EDVDS tire model queries the environment to use the current elevation, surface normal vector and friction beneath each tire.
If you would like to see an example of how to use EDVDS, download the Tutorial from the EDVDS Physics Manual. (Download time for this 1.9 MB Adobe PDF file is about 2 - 5 minutes, depending upon your connection speed.)
- Selectable from HVE's built-in databases, according to Type, Make, Model, Year and Body Style
- Tires selectable from HVE's built-in databases, according to Type, Manufacturer, Model, and Size.
- Several Database Sources (Generic, EDVDB, User and others) for both vehicles and tires
- Solid and Tandem Axle Suspension types with roll center height, lateral spring spacing, ride rates, damping rates, anti-sway bars, jounce/rebound stops, and roll steer
- Inter-vehicle Connections (fifth wheel/king pin, pintle eye/hook)
- Brake System with lag/rise time, brake torque ratio and proportioning at each wheel
- Drivetrain with engine power vs torque curves, transmissions with up to 12 numerical ratios, and differentials with up to 3 numerical ratios
- All data are user editable
- Complete vehicle model specification published in SAE 950308
- 3-D Terrain Model (from DXF file or several other sources) with user-definable friction zones for tire-road interaction
- Local Gravitational Constant
- 3-D drag-and-drop positioning of vehicles in the environment
- Open-loop Driver Control Tables (steering, braking, throttle, gear selection)
- Simulation Controls (integration time-steps, maximum simulation time, output time interval and termination conditions)
- Vehicle Kinematics (position, velocity, acceleration vs time)
- Vehicle Kinetics (summation of forces and moments vs time on sprung mass from suspension and inter-vehicle connections vs time)
- Tire Data (contact patch coordinates, forces, moments, radius, longitudinal slip, slip angle, skid status, terrain properties at the contact patch vs time)
- Wheel Data (coordinates, steer angle, spin velocity, suspension force and deflection, drive and brake torque, air chamber pressure, lining temperature vs time)
- Driver Data (throttle, brake pedal force, treadle valve pressure, steering wheel angle vs time)
- Collision Pulse (acceleration vs time history for occupant simulation)
- Connection Data (articulation angles, moments and forces vs time at each inter-vehicle connection)
- 3-D Visualization of vehicle motion at user-specified time intervals
- Accident History (initial and final positions and velocities)
- Driver Controls (steering, braking, throttle, gear selection)
- Simulation Controls (numerical integration parameters)
- Vehicle Data (dimensions, inertias, suspension properties, steering system properties, brake system properties at master cylinder and wheels, tire properties)
- Messages (event-related diagnostics)