Card 25 - Steer Degree-of-Freedom: Veh1

The effects on vehicle motions of responses of undamaged steering systems to external forces can be significant during spinout motions. This option has been added to permit the inclusion of those effects on the vehicle trajectory. The inputs are on Cards 25 and 26.

M-edit includes the provision to include the effects of a steer degree-of-freedom (SDOF) steering system during a simulation run. The steer degree-of-freedom was included to model the effects of an undamaged steering system during spinout subsequent to a collision. The model is similar to the SDOF included in the Highway Vehicle Object Simulation Model (HVOSM) program (e.g., Ref. 15).

 

 

XIPS1

CPSP1

OMGPS1

AKPS1

EPSPS1

XPS1

PSIF1

PSIFD1

TSDOF1

 

25

 

Card:  Field

Variable

 

Description

Original Units

Metric Units

 

25:1

 

XIPS1

 

Vehicle #1 Steer degree-of-freedom Option Inputs

Steering system moment of inertia about the wheel steering axes. (range approx. 200-1000 lb-sec-in)

 

 

lb-sec-in

 

25:2

CPSP1

 

Steering system coulomb friction torque, effective at the wheel steering axes. (range approx. 500-2000 lb-in)

lb.-in

 

25:3

OMGPS1

 

Front wheel steer angle at which steering limit stops are engaged.

(range approx. 20-30 degrees)

Degrees

 

25:4

AKPS1

 

Stiffness of the steering limit stops, effective at the front wheel steering axes. (range approx. 50,000-100,000 lb-in/rad).

lb-in/rad

 

25:5

EPSPS1

 

Friction lag in the steering system. (range approx. 2-17 deg/sec)

Deg/sec

 

25:6

XPS1

 

Front wheel pneumatic trail. (range approx. 0.50-1.50)

inches

 

25:7

PSIF1

 

Initial steer angle used if TSDOF1 = 0.0.

degrees

 

25:8

PSIFD1

 

Initial steering system velocity, used if TSDOF1  =  0.0.

deg/sec

 

25:9

TSDOF1

 

Start time for steer-degree of freedom.

seconds

 


More:

Card 25, Seq 1 - Steer Degree-of-Freedom: Veh 1