COSMOSMotion Simulation -- y it fails?

Hi, guys, I am back with my tracked car.


Now, I've succeed to make a part of it move , that is one of its four wheels, which, however, is made of a gear wheel and an idle wheel, connected by a track--let's call it a tracked-wheel. The track is itself an assembly with 30 basic track pads -- It is really a heavy work to assemble the whole vehicle.


I can make that tracked-wheel move alone(without the body and the other three tracked-wheels), no problem. But once the simulation is carried out onto the whole vehicle (one body plus four tracked-wheels), it always fails.


COSMOSMotion always gives five possible failure causes to the user, they are all the same everytime, and you will never know which exactly causes the failure. That's why i am here. I would like to listen to any idea about y it fails for a whole rover while it always works for one of the tracked-wheels?


btw, i've also tried a half car, which is composed of the body and only two tracked-wheels, and it also failed.


any idea...I've got stuck again


cheers
Edited by: swstudy

Seems to me that CM is getting bound up by having two or more of the same mechanisms working simulataneously. Your model works ok with one mechanism but fails with more than one because CM is 'feeling' overconstrained. Have you tried putting a bushing (non-rigid constraint) anywhere in your mechanisms? CM cannot easily cope with sharing loads so bushings are there to help. Are you using 2008 or an earlier version? I ask this because 2008 has a switch to make all constraints as bushings and this could be invoked as a simple test.

thanks, i am using version 2007, and I have added a spring to connect the front half and the rear half of the vehicle, but it still failed.


My car has four wheels, but not as the common wheels. Now a single wheel can move, a half-body with two wheels, each on one side, can move too. but for a whole car with four wheels, it always fails. I split the car body into two half, and add a spring to connect them, but it doesnt work.


What is wrong? any good idea?