## Search found 387 matches

Tue May 05, 2020 11:34 am
Forum: OpenSim
Topic: How large are the residual joint moments and residual actuator forces predicted by CMC as a percentage of the body weigh
Replies: 1
Views: 247

### Re: How large are the residual joint moments and residual actuator forces predicted by CMC as a percentage of the body w

I think converting body mass to weight first so that it's in units of N is correct. I also think that while calculating the residual forces as a percent of body weight makes sense. Percent body weight makes a little less sense with residual moments since the units aren't the same, but on the whole s...
Mon Apr 20, 2020 1:25 pm
Forum: OpenSim
Topic: Reserve actuators optimal force value
Replies: 6
Views: 1125

### Re: Reserve actuators optimal force value

I believe that is referring to the peak joint torques for the motion (such as the output when you run inverse dynamics) rather than the peak joint torque of the model.
Sun Apr 19, 2020 10:07 pm
Forum: OpenSim
Topic: Reserve actuators optimal force value
Replies: 6
Views: 1125

### Re: Reserve actuators optimal force value

Yes, in general you want to have reserve actuators' optimal forces to be small. One other reason for this is how the static optimization problem is posed. If the optimal forces of the reserve actuators are high, then it's "cheap" to use in the cost function of static optimization. Thus, they should ...
Thu Apr 16, 2020 10:01 am
Forum: OpenSim
Topic: Apply new external force over measured kinematics and GRFs
Replies: 5
Views: 1097

### Re: Apply new external force over measured kinematics and GRFs

Trying to predict how the GRF changes due to an external perturbation is really difficult. You're taking a very interesting approach, but as you see this leads to some big residuals because it's hard to know how to change the COP. You might be able to do some of this through trial-and-error or tryin...
Thu Apr 16, 2020 9:21 am
Forum: OpenSim
Topic: Inverse Dynamics - Torque and Forces
Replies: 2
Views: 474

### Re: Inverse Dynamics - Torque and Forces

No worries at all, I don't know where this would be in the documentation. Overall, you're correct. Depending on the type of each individual joint in the model, inverse dynamics will return a moment or force, or both for each joint. And as you noted, if the coordinate related to a joint is rotational...
Thu Apr 09, 2020 3:11 pm
Forum: OpenSim
Topic: Passive joint moment that's a function of coordinates at multiple joints
Replies: 7
Views: 909

### Re: Passive joint moment that's a function of coordinates at multiple joints

Unfortunately, I think the provided classes in OpenSim don't give a clear way to implement your problem using MATLAB. Creating a class to do this in C++ would likely work but may not be trivial to do. I wonder if there could be a way around this by implementing your equations in MATLAB. Depending on...
Thu Apr 09, 2020 3:00 pm
Forum: OpenSim
Topic: get the adjusted marker positions after inverse kinematics
Replies: 1
Views: 278

### Re: get the adjusted marker positions after inverse kinematics

I can't think of any way to easily do this off the top of my head. One possible way to work around this would be to use the Analyze tool with a PointKinematics analysis where you specific points that coincide with the markers of interest.
Wed Apr 08, 2020 10:00 am
Forum: OpenSim
Topic: Creating Custom Controller in Matlab
Replies: 3
Views: 760

### Re: Creating Custom Controller in Matlab

I looked through the TugOfWar code from 4.1, and I see the controls section between L260 and L275. It looks like it's also using a PrescribedController as you are using with a linear function. Is this what you're referring to? If so, I think it should be doable. LinearFunction should be available in...
Tue Apr 07, 2020 5:06 pm
Forum: OpenSim
Replies: 2
Views: 587