AVIEW: initial conditions for a manipulator with stiffness
AVIEW: initial conditions for a manipulator with stiffness
(OP)
I am using ADAMS view 12.0, Im trying to do a simulation of a manipulator. The manipulator holds a heavy payload, and they are connected by bushing. I set the initial conditions that are rotation displacements for each joint, and if I run the simulation for 0.2sec, the joint rotate unexpextedly due to the stiffness by the bushing connected with the heavy payload, so I can not make an expected initial pose. In the case of rigid connection, there is no problem. How can I solve this problem?.
Thank you in advance.
Thank you in advance.
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RE: AVIEW: initial conditions for a manipulator with stiffness
The effect you see is real, we see it all the time on large models, so our custom pre-processor actually goes through a static convergence funnel (as it is known) every time.
In effect we assemble the car in mid air, then drop the car onto the ground from a small height and let it sort itself out, then we start testing.
MSC support probably has some articles on the subject, here's our funnel
! Static Funnel
equil/maxit=75, err=10000, imb=10000, stab=10000
con/fun=user(1010,555)
equil/maxit=75, err=1000, imb=1000, stab=100
con/fun=user(1010,555)
equil/maxit=75, err=100, imb=100, stab=10
con/fun=user(1010,555)
equil/maxit=75, err=0.1, imb=0.1, stab=0.1
con/fun=user(1010,555)
equil/maxit=75, err=1.0000e-03, imb=1.0000e-01, stab=5.0000e-02
The other solution is to work out the correct, static, geometry and then entering preloads in the bushes. Not very easy.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.