Coordinate Systems and Output Requests
Tydex-C Axis System
The “C” is for wheel center, and the C axis system has these properties:- The origin of the C-Axis system is the wheel center.
- The X axis lies in the wheel plane and is parallel to the ground plane and points in the forward direction.
- The Y axis is perpendicular to the wheel plane and points towards the vehicle’s left side so that a positive rotation of the wheel and tire about the Y axis rolls the tire forward.
- The Z axis lies in the wheel plane, differs from vertical by inclination angle, and is perpendicular to the X and Y axes (Z = X x Y).
Tydex-W Axis System
The “W” is for wheel. The Tydex-W axis system considers the local slope of the road where the tire contacts the road, rather than assuming the road is flat. The Tydex-W axis system has these properties:- The origin of the W axis system lies at the ideal contact point between the wheel plane and local road plane, which is the intersection of the Tydex C System Z axis with local road plane.
- The X axis points forward along the line of intersection between the wheel plane and the local road plane.
- The Z axis is parallel to the local road normal and hence perpendicular to the local road plane.
- The Y axis is the projection of the wheel spin axis (Tydex C-Axis System Y) into the local road plane. The Y axis is perpendicular to both the X and Z axis (Y = Z x X).
SAE System
- X is forward
- Y is to the right
- Z is down
- Tire rolling states
- (Branch ID 1)
-
Component Name Units x rolling radius model units y omega rad/sec z omega free rad/sec - Tire kinematic properties in TYDEX-W (ISO) axis system
- (Branch ID 2)
-
Component Name Units x longitudinal slip % y lateral slip angle radians z inclination angle radians - Tire contact patch forces in TYDEX-W (ISO) axis system
- (Branch ID 3)
-
Component Name Units x longitudinal force model units y lateral force model units z vertical force model units r1 residual overturning moment model units r2 rolling resistance moment model units r3 aligning moment model units - Tire contact patch forces in SAE axis system
- (Branch ID 4)
-
Component Name Units x longitudinal force model units y lateral force model units z vertical force model units r1 residual overturning moment model units r2 rolling resistance moment model units r3 aligning moment model units - Tire kinematic properties in SAE axis system
- (Branch ID 5)
-
Component Name Units x longitudinal slip % y lateral slip angle radians z inclination angle radians - Tire forces at hub in TYDEX-C axis system
- (Branch ID 6)
-
Component Name Units x longitudinal force model units y lateral force model units z vertical force model units r1 residual overturning moment model units r2 rolling resistance moment model units r3 aligning moment model units - Contact patch locations along the plane of the tire in the GFORCE rm marker
- (Branch ID 10)
-
Component Name Units x road contact point x location model units y road contact point y location model units z road contact point z location model units r1 tire radial penetration into the road surface model units - Hub velocities of the tire in the GFORCE rm marker
- (Branch ID 11)
-
Component Name Units x rim center velocity in longitudinal direction model units y n/a n/a z rim center velocity in vertical direction, along road normal model units
<Post_Request
id = "70000063"
comment = "Tire - Front Rad, OmegaActual, OmegaFree (left)"
type = "USERSUB"
usrsub_param_string = "USER(902,1,11001)"
usrsub_dll_name = "mbdtire.dll"
usrsub_fnc_name = "tireReq"
/>