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Wheel rolling problem

Question asked by Kumararaja Eedara on May 29, 2011
Latest reply on May 30, 2017 by Nayan Jyoti Baishya

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Hii..

I've a problem in simulating rolling motion of a wheel on a surface.When i added motor the wheel is not rolling forward.It is just rotating about its axis only.

Please help me.I'm attaching the assembly too.

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wheel2.SLDASM.zip255.3 KB
practicewheel_surface.SLDPRT.zip105.3 KB
practice-wheelSLDPRT.SLDPRT.zip63.2 KB

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Deepak Gupta May 29, 2011 8:45 AM
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Welcome to SW forums Kumararaja

Are you just looking for the animation or some simulation for these two parts.

Also please delete the other two similar post of yours.

You might also find this post helpful for your future reference.
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- Kumararaja Eedara @ Deepak Gupta on May 29, 2011 10:29 AM
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  Thanks for ur quick response deepak.
  I'm NOT looking just for animation.
  I want to perform simulation, like by varying the surface (Road) texture differant forces acted on it etc.
  But for me to proceed any more i need to be first able to achieve that motion.
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  - John Sutherland @ Kumararaja Eedara on May 30, 2011 3:02 AM
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    You need 3D contact between wheel and road.
    
    I was never able to have friction in 3D contact, so instead of putting motors on the wheels just give the vehicle an initial velocity.
    
    SW was unable to do everything I wanted with wheeled vehicles.
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Jim Boland May 31, 2011 10:20 AM
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In the attached files I have the wheel rolling across the plate in a general diagonal direction. Some things to note about this solution:
- The problem with the wheel not rolling in your original problem is the tangent mate. Remember that you are using SW Motion to solve the physics of the problem, that means that the interaction of the wheel on the plate is a result of the mass of the wheel, gravity, contact and friction, not a tangent mate. So, while the tangent mate is OK to get the initial position of the wheel, it needs to be suppressed during the motion study.
- As you have a single wheel, it is not going to roll across an undulating surface without falling over, so you need to have a mate or some geometry to hold it upright. In your original problem you used a parallel mate to hold it upright. The problem with this is that it doesn't allow the wheel to take a path that is in any other direction, such as across the diagonal of the plate, or to change direction as dictated by the physics of the problem. I changed the mate to make the rotational axis of the wheel parallel to the bottom face of the plate. This allows the wheel to roll in other directions as well as change direction based on the physics of the interactions.
- The amount of friction is controlled in the Contact PropertyManager. I had to crank the value up realtively high to get the wheel to get over the hill because it is a very steep hill. With lower values, the wheel would get part way up the hill and then just slip.
- I slowed the motor down and lengthened the animation to be able to see the motion better.
- I added an appearance to the sides of the wheel to be able to see the rotation easier.
- You can see the wheel piecing the surface of the plate which at first may appear to be incorrect, but this is a result of SW Motion being a "rigid body" solver where the bodies cannot deform. In the physical world, a wheel rolling on a surface will cause deformation in both the wheel and surface with that deformation acting as a spring force (equal and opposite) to achieve equilibrium. As the bodies cannot deform in the analysis, the bodies overlap with the amount of overlap proportional to the spring constant set in the options. While this may not look great in animations, it should not make any difference in the analysis solution.
Hope this helps.
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- wheel2.avi7.4 MB
- wheel2.zip655.0 KB
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- Nayan Jyoti Baishya @ Jim Boland on May 30, 2017 8:14 AM
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  Dear Sir,
  In regards to above problem, can we find reaction forces on the wheel by the surface. Kindly, help me with a method to find the reaction forces.
  Best Regards
  Nayan
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  - Nayan Jyoti Baishya @ Nayan Jyoti Baishya on May 31, 2017 10:22 AM
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    Sir,
    I figure out the solution. Its using contact forces.
    Thank You
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Wheel rolling problem

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