NDEV

Input

Integer

NDEV must specify the logical output device for error messages. USRMES and ERRMES can be used in place of writing to NDEV device.

ISWTCH

Input

Integer

ISWTCH is a copy of USE_MODE which a variable in Tire property file. USE_MODE is a user controlled variable to select among the different operating modes of tire.

If a user has different kinds of tire model than in JOBFLG = 11 the User Tire Interface will send the ISWTCH as a input to the tire subroutine and at this JOBFLG specific algorithm is selected depending on the value of the ISWTCH.

Example:

USE_MODE

0: Evaluation of Fz only

1: Evaluation of all forces

10: Steady state behavior

20: Include relaxation behavior

100: Smooth road contact

200: Road contact for 3D roads

If USE_MODE = 121 than it means that the ISWTCH value at JOBFLG = 11 is 121 and this value specifies

In a similar manner, ISWTCH can be defined so that by addition of digits which represents the corresponding evaluation schemes can be represented by this parameter.

JOBFLG

Input

Integer

The User Tire Interface calls the User Tire model several times during the simulation with different JOBFLG. The JOBFLG variable decides the execution model (initialization, reading tire property file, initial condition) of TYRE. The User Tire Interface expects some variables to be updated according to the JOBFLG value. The JOBFLG is called in following order:

JOBFLG = 1 initialization mode

This mode is for initialization of the tire, it will be called once for each tire.  After this call the User Tire Interface expects the tire model to return the maximum array size for the arrays to store the tire properties, road properties, state variables and output variables.

Outputs:

NTYPAR, NDEQVR, NVARS, NWORK, NIWORK, NROPAR

JOBFLG = 2 reading tire and road property files

In this mode tire model reads the tire and road property files and stores the parameters in TYPARR, ROPAR and WRKARR array.

Inputs:

NCHTDS, CHTDST, NCHRDS, CHRDST, ISWTCH, IDTYRE

Output:

TYPARR, ROPAR, WRKARR

JOBFLG = 11, actual array size

Depending on the ISWTCH or depending on the parameters in tire property file the number of differential equations can vary which in turn changes the number of states therefore User Tire Interface needs to be updated about the size of the state and work arrays.

Input:

ISWTCH

Output:

NTYPAR, NDEQVR, NVARS, NWORK, NIWORK

JOBFLG = 6, initial conditions

In this call depending on the kinematic inputs (position, velocity, orientation) of the wheel center, the initial conditions for state variables can be calculated.

Inputs:

ISWTCH, TIME, DIS, TRAMAT, ANGTWC, VEL, OMEGA, OMEGAR, DEQVAR, TYPARR, ROPAR

Output:

DEQINI

JOBFLG = 0, normal call

In this call tire model calculates the force and moments on tire.

Inputs:

ISWTCH, TIME, DIS, TRAMAT, ANGTWC, VEL, OMEGA, OMEGAR, DEQVAR, TYPARR, ROPAR Outputs: FORCE, TORQUE, DEQDER, VARINF, WRKARR, and IWRKAR

JOBFLG = 99, final call

This is the final call to tire model and is used to inform tire model to free allocated memory, etc.

IDTYRE

Input

Integer

Specifies the tire ID.

TIME

Input

Real

Current simulation time.

DIS

Input

Real array (3)

Specifies the x, y, z coordinates of the wheel carrier at the wheel center with respect to the earth-fixed axis system expressed in the earth-fixed axis system. Earth fixed axis system and Road reference marker coordinate system are same.

TRAMAT

Input

Real array (3,3)

Specifies the transformation matrix to transform data from the wheel Carrier coordinate system to the earth-fixed axis system.

ANGTWC

Input

Real

Specifies the rotation angle of the rim w.r.t. the wheel carrier (used for positioning /triggering of non-uniformities of the tire).

VEL

Input

Real array (3)

Specifies the translational velocities of the wheel career at the wheel center with respect to the earth-fixed axis system expressed in the C-frame (defined in the TYDEX - Format).

OMEGA

Input

Real array (3)

Specifies the angular velocities of the wheel carrier with respect to the earth-fixed axis system expressed in the wheel carrier (C-frame) axis system.

OMEGAR

Input

Real

Specifies the rotation speed of the rim with respect to the wheel carrier.

NDEQVR

Input

Integer

Specifies the dimension of the DEQVAR array. It is the number of states required by tire model.

DEQVAR

Input

Real array (NDEQVR)

DEAQVAR contains the integrated values of the DEQDER. The initial values are given by DEQINI.

NTYPAR

Input

Integer

Specifies the dimension of the TYPARR array. If NTYPAR is equal to zero than TYPARR contains no available values.

TYPARR

Input

Real array (NTYPAR)

It contains the parameters of the current tire model. If TYPARR is not available than NTYPAR must be 0 and in this case tire parameters can be read from a data file specified in CHTDST.

NCHTDS

Input

Integer

Specifies the dimension of CHTDST array. If NCHTDS is 0 than CHTDST contains no file name and in this case the simulation will be terminated as tire property file is used to inform User Tire Interface about the Tire subroutine name and the library name.

CHTDST

Input

Character array
(NCHTDS)

It contains the tire property file name which has tire parameters stored in it.

ROAD

Input

Function Pointer

It contains the road subroutine which is called by the tire subroutine to calculate normal of the road and the tire contact point with the road.

IDROAD

Input

Integer

Specifies which road model is used. Currently this parameter is not supported in User Tire Interface.

NROPAR

Input

Integer

Specifies the array size of ROPAR. If NROPAR is 0 than the road properties are read from a file specified in CHRDST.

ROPAR

Input

Real array
(NROPAR)

It contains the road parameters. If ROPAR is not available than NROPAR should be set to 0.

NCHRDS

Input

Integer

Specifies the dimension of CHRDST array. If NCHRDS is 0 than CHRDST contains no file name.  If the road function from MotionSolve is used CHRDST should contain the name of the road property file otherwise the simulation will be terminated as road property file contains the name of the road function which is being used.

CHRDST

Input

Character array
(NCHRDS)

It contains the name of the file which contains the road parameters. It should contain the name of the road function and “mbdtire” as the library name while using the road function from MotionSolve.

FORCE

Output

Real array (3)

It contains the force applied by the tire onto rim at the center of the wheel. It is expressed in wheel career axis system (C-frame).

TORQUE

Output

Real array (3)

It contains the torque applied by the tire onto the rim. It is expressed in the wheel career axis system (C-frame).

DEQINI

Output

Real array
(NDEQVR)

Initial conditions of the DEQVAR. At JOBFLG = 6 the tire model should return the initial conditions for the DEQVAR. The value of DEQINI is ignored at other JOBFLGS.

DEQDER

Output

Real array
(NDEQVR)

It contains the derivative of the DEQVAR that needs to be integrated by the MotionSolve. At JOBFLG =0 and JOBFLG = 6, the tire subroutine should return the derivative of the DEQVAR in DEQDER array.

TYRMOD

Output

Character array (256)

It contains the information about name, type, release of the tire model.

NVARS

Output

Integer

Specifies the dimension of the VARINF array.

VARINF

Output

Real array
(NVARS)

It contains the information about the internal variables of the tire model. These are values like slip angle, longitudinal slip, etc.

Click here to see a complete list:

NWORK

Output

Integer

Specifies the dimension of the real work array (WRKARR).

WRKARR

Output

Real array
(NWORK)

It is for the internal use by the tire model, generally contains the last content of the work array.

NIWORK

Output

Integer

Specifies the dimension of the real work array (IWRKAR).

IWRKAR

Output

Integer array
(NIWORK)

Same as WRKARR but for integers.

IERR

Output

Integer

It contains an integer value that specifies the type of error.

0: No error

1: Warning

2: Error- don’t use the actual results

3: Fatal error- Calling program should stop.