hi Sherm,

Thanks for the reply. I found it worked well if I removed the delay component.
I wonder if the Measure::Delay needs to be initialized, and how delay component affects
system initialization and the cache values?

Thanks in advance,
Jiang

hi Sherm,

Thanks very much for your reply. I have checked my code and found the udot vector
in state vector has some elements whose value are NaN. Do you have any idea about
this problem?

Thanks in advance

jiang

hi all, I have a question about how integrator selected the step size. I run the same simulation for several times, finding that the integrator choose different step size. Sometimes step size was big and simulation time is short, but sometimes step size is very small and simulation time is very long...

hi Sherm,

Thank you very much for your reply.
That is very helpful for me to understand SimTK::vector and Array.

best regards,
jiang

hi, I have created a SimTK：：Vector and a std::vector. I found that the resize() method was different. if we have two empty vector SimTK：：Vector a and std::vector b now, a.resize(10) will return a vector with ten elements but without any default value (the value is random). b.resize(10) will return a...

hi, Your attachment is good . Actually I would like to ask if you are conducting forward dynamics simulation in your objective function. x[0] was constrained to 25 all the time during FD simulation? or you are not conducting forward dynamics simulation in your objective function? like simple optimiz...

hi, Very difficult to understand what is your question. What is [X]? What is X[0]? Is X a vector and X[0] is the first element of it? Are you trying to fix the value of X[0] to 25 at the final time of the simulation? or you are trying to fix it as a constant 25 all the time during the simulation? be...

hi,

There are some method like getAcceleration() or getSpeed() available in OpenSim to access coordinate or body acc. and speed.
w=(Theta(i)-Theta(i-1))/(Time(i)-Time(i-1)) is not precise linear approximation.

best regards,
jiang

hi nithin, I dont think marker is necessary to calculate the vector. You can try: SimTK::Vec3 B_com, B_cominGround; Model aModel("aModel"); OpenSim::Body B_body = aModel.getBodySet().get("B_body"); B_body.getMassCenter(B_com); SimTK::State s = aModel.initSystem(); aModel.getSimbodyEngine().transform...

hi, I read the following document and understood how to calculate the joint torque. http://wiki.simtk.org/opensim/FrontPage?action=AttachFile&do=get&target=HowToComputeMuscleMomentArm.pdf Now i want to calculate d τθ/ d θ, where τθ is joint torque at θ, θ is the joint angle. Is there any guidance fo...