Vehcile Co-ordinate System
Vehcile Co-ordinate System
(OP)
Does each OEM has different vehicle co-ordinate system?
Each has vehicle co-ordinate system with respect to C.G. of a vehicle?
While doing vehicle testing what should be the component position? with respect to C.G or with respect to ground level?
Each has vehicle co-ordinate system with respect to C.G. of a vehicle?
While doing vehicle testing what should be the component position? with respect to C.G or with respect to ground level?





RE: Vehcile Co-ordinate System
RE: Vehcile Co-ordinate System
I was talking the component position while doing the initial assembly & mentioned the CG as a reference point for a static condition of vehicle.(C.G. won't move)
Each vehicle has Vehicle coordinate. SO WHAT IS THE REFERENCE FOR A VEHICLE COORDINATE?
RE: Vehcile Co-ordinate System
- some point x distance in front of the car
- where transmission and drive train are connected
- center of windshield
- center of front or rear axle at nominal loading
Almost always, the origin is on the car's median symmetry plane.http://www.EsoxRepublic.com
RE: Vehcile Co-ordinate System
TTFN
RE: Vehcile Co-ordinate System
RE: Vehcile Co-ordinate System
There is the SAE standard coordinate system detailed in SAE J670 Vehicle Dynamics Terminology. It is not widely used, however, for vehicle development. I use:
X positive reward; origin at the front axle position.
Z positive up; origin at convenient position on vehicle (on a structural fame perhaps, depends on the vehicle).
Y positive left; centered on symmetry plane.
For the vehicle dynamics work, it is different.
X positive forward; origin at the front axle position.
Z positive up; origin at ground plane
Y positive right; centered on symmetry plane.
Best regards,
Matthew Ian Loew
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Vehcile Co-ordinate System
In my experience, all the platforms I have worked on have tended to have Z=0 at floor level and Y=0 along the centreline of the vehicle. X however has been a different issue - some companies have had it at the bottom of the oil sump - some level with the centreline of the front wheels. Others preferring to have it on the front most point of the bumper at Y=0.
When I first entered into OEM design for FMC, I used to use PDGS which automatically set up the XYZ datum depending upon which car program you were working on. Nowadays with Catia and IDEAs - it seems that the global co-ordinate system is used as a datum. I have never personally come across an OEM program that has used the occupant or COfG as the datum position. Some powertrain applications however and standard parts are drawn in a local co-ordinate system and then moved appropriately to their equivalent position on the vehicle.
hope this helps
Sean
RE: Vehcile Co-ordinate System
The coordinate axis needs to be fixed relative to something that doesn't move much during or between successive programs, I believe the crease where the firewall hits the floor may be the ancestral location that was regarded as fixed.
Cheers
Greg Locock
RE: Vehcile Co-ordinate System
One of the "big three" uses the following dimensions when
locating the Vehicle Origin from where all vehicle dimensions are taken from.
The X plane runs from front to back of vehicle when viewed in side view ( front of vehicle pointing left).
The Y plane runs from side to side of vehicle ( door mirror to door mirror) when viewed in front, rear or plan view.
note: the right hand side of vehicle is always positive Y and the left hand side of vehicle is always negative Y.
This is irrespective of the actual drive of the vehicle.
The Z plane runs vertical from the bottom to top of vehicle when in side view.
X 0 = 2000mm from the vehicle centreline section, of the IP rear most point.
Y 0 = Centre line of Vehicle.
Z 0 = 500mm below the lowest point of the front door seal.
Regards
Samanthajane
RE: Vehcile Co-ordinate System
some few questions associated to this forum:
1. Before starting the solid model how do one make sure that the model will be in a vehicle co-ordinate position?
I mean to say before the any new vehicle program starts the OEM people know the each subassembly co-ordinates?
Do you think it is appropriate to put the component in a vehicle position after the solid model is done?
Thanks in advance,
RE: Vehcile Co-ordinate System
One was a military vehicle manufacturer, where each part was modeled at the coordinate system, them mated to the proper placement at the assy level.
Aircraft manufacturers I have worked at do it the other way. The parts are modeled in space at their position in the finished aircraft (except of course fasteners and related hardware). The parts were still properly mated, but even without the mating, they would appear in the correct location.
The logic seems simple. If the part is going to be used in multiple assembles, each at a different location, then model at the coordinate system. If the parts are unique and used only at one location on one vehicle, then model relative the vehicle absolute coordinates.
RE: Vehcile Co-ordinate System
You can build your model in any coord system you like, it's when you want to talk to other people you need to move it and spin it into global.
Cheers
Greg Locock
RE: Vehcile Co-ordinate System
As ewh quite rightly points out it's logical to model the Part / Assembly in it's vehicle line position so as to check mating issues.
Within C3P Ideas, the option is available to model the component either in vehicle line position or at global.
The question come's as to how other users of the component or other designers trying to match to the "new" component, know the part /assembly is in it's correct vehicle position.
This can be made known by making a Master Package, which has all components as sub-assemblies as instances, that can be moved into their correct vehicle positions but will not move the original components.
Therefore other users will know that if they reference the Master Package the components within will be in vehicle line.
Regards
Samanthajane
RE: Vehcile Co-ordinate System
RE: Vehcile Co-ordinate System
x=fore/aft or front to back
y= cross car or from centerline of vehicle outbnoard
z=up/down
US OE's use xyz coordinate convention
some Japanese use t,b,h for x,y,z but is just change of letters.
RE: Vehcile Co-ordinate System
I've seen the most convenient origins at the center of the front wheel spindles.
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Hydroformer