Search found 99 matches
- Wed Apr 03, 2013 6:17 pm
- Forum: OpenSim
- Topic: Why does HuntCrossleyForce apply torques?
- Replies: 3
- Views: 799
Why does HuntCrossleyForce apply torques?
Hi, I just understood that the HuntCrossleyForce contact model applies both forces and torques to the contact sphere, While according to this paper, it should only be a spring and damper force actuator (not a torque actuator). http://www.stanford.edu/group/nmbl/publications/pdf/Sherm2011.pdf When I ...
- Sun Mar 24, 2013 4:13 pm
- Forum: OpenSim
- Topic: FD returns "Unknown exception" when using wrapping cylinder
- Replies: 4
- Views: 795
Re: FD returns "Unknown exception" when using wrapping cylin
Hi Ayman,
the Osim files are attached
Tnx
the Osim files are attached
Tnx
- Thu Mar 21, 2013 7:34 pm
- Forum: OpenSim
- Topic: FD returns "Unknown exception" when using wrapping cylinder
- Replies: 4
- Views: 795
Re: FD returns "Unknown exception" when using wrapping cylin
Hi Ayman and Thank you, Here is the simple version. If DefaultModel (line 8) contains wapping cylinders, this code will generate an error, but it will work if the loaded model on line 8 does not have wraping objects. thanks Sina P.S: How can I send you the osim files that I am using? I cannot upload...
- Mon Mar 18, 2013 4:31 pm
- Forum: OpenSim
- Topic: FD returns "Unknown exception" when using wrapping cylinder
- Replies: 4
- Views: 795
FD returns "Unknown exception" when using wrapping cylinder
Hi all. I am using a model which uses wrapping cylinders for some of the muscles. I am using this model to solve a dynamic optimization problem and I have two problems. First, let's have a look at my algorithem: - Load the Osim File - for i=1:1000 --- create a random muscle excitation pattern for ea...
- Mon Feb 25, 2013 10:14 pm
- Forum: OpenSim
- Topic: CoordinateLimitForce - nonLinear region
- Replies: 2
- Views: 585
Re: CoordinateLimitForce - nonLinear region
Thank you Sherm
- Mon Feb 25, 2013 9:00 pm
- Forum: OpenSim
- Topic: CoordinateLimitForce - nonLinear region
- Replies: 2
- Views: 585
CoordinateLimitForce - nonLinear region
Hi everyone. I am using CoordinateLimitForce to represent ligaments in my model. I know that this force has a constant stiffness except through the transition region which uses a non-linear function to change the stiffness smoothly from zero to the specified stiffness. I was wondering if I can know ...
- Wed Feb 13, 2013 9:07 pm
- Forum: OpenSim
- Topic: Does OpenSim report state equations?
- Replies: 33
- Views: 10393
Re: Does OpenSim report state equations?
Thankyou Ajay.
- Mon Feb 11, 2013 9:30 pm
- Forum: OpenSim
- Topic: Does OpenSim report state equations?
- Replies: 33
- Views: 10393
Re: Does OpenSim report state equations?
Hi again, I reckon it shouldn't be that tricky, because the forward dynamic tool needs the same ydot vector in order to integrate the state equations forward in time. Something like y(t+h) = y(t) + h*ydot( t, y(t), u(t) ) which is a first order Euler method. Of course the FD tool uses more accurate ...
- Mon Feb 11, 2013 6:01 pm
- Forum: OpenSim
- Topic: Does OpenSim report state equations?
- Replies: 33
- Views: 10393
Re: Does OpenSim report state equations?
Hi Sherm. In General, an optimal control problem is to find the optimum control u* which causes the system: ydot(t) = f (y(t), u(t), t) (eq.1) To follow the optimum trajectory y* that minimizes/maximizes a cost function. In (eq. 1) y is the state vector, u is the control vector and t is the independ...
- Sun Feb 10, 2013 10:23 pm
- Forum: OpenSim
- Topic: Does OpenSim report state equations?
- Replies: 33
- Views: 10393
Re: Does OpenSim report state equations?
Hi Sherm and thank you for the reply. I am using the OpenSim API to solve an optimal control problem and I am using an open source optimizer which is written in C++. (Everything is happening in C++). I will try my best to avoid a super technical question! I am trying to solve a constraint problem wh...