Search found 21 matches

by Erik Dijkstra
Thu Feb 19, 2015 2:31 pm
Forum: OpenSim
Topic: URGENT! Advanced API, Actuator, Plugin, SO
Replies: 7
Views: 2117

Re: URGENT! Advanced API, Actuator, Plugin, SO

The four vertical force actuators are able to generate the 50N each. For other motions it might be that the 'force-length' and 'force-velocity' relations make the maximum force an actuator can generate zero, but looking at the motion i use now they are within their force producing ranges. I guess fo...
by Erik Dijkstra
Thu Feb 19, 2015 2:58 am
Forum: OpenSim
Topic: Inverse Dynamics: Plots are upside down?
Replies: 1
Views: 444

Re: Inverse Dynamics: Plots are upside down?

Hi Jas, I think the different joint sign conventions in the model are the reason for the curves to be "upside down" for you. We have seen similar things when directly comparing Vicon results with results from OpenSim plots. You can easily check this by looking at the kinematics. Hope this helps, Erik
by Erik Dijkstra
Thu Feb 12, 2015 1:41 am
Forum: OpenSim
Topic: URGENT! Advanced API, Actuator, Plugin, SO
Replies: 7
Views: 2117

Re: URGENT! Advanced API, Actuator, Plugin, SO

1. Sorry that is my bad. The actuators without a direction specification are for the vertical Y direction. If there where no actuators acting for the vertical direction the forward simulation would have shown the block falling through the 'floor', which is undesirable. 2. I am not sure I understand ...
by Erik Dijkstra
Wed Feb 11, 2015 2:40 am
Forum: OpenSim
Topic: URGENT! Advanced API, Actuator, Plugin, SO
Replies: 7
Views: 2117

Re: URGENT! Advanced API, Actuator, Plugin, SO

Hi, I made a simple environment of a block moving on the floor with the new actuators on the four base corners. At first I tested a forward simulation and this looks good. Next I ran some static optimizations of motions resulting from the forward dynamic simulation and some self made motions. This a...
by Erik Dijkstra
Tue Feb 03, 2015 11:45 pm
Forum: OpenSim
Topic: URGENT! Advanced API, Actuator, Plugin, SO
Replies: 7
Views: 2117

Re: URGENT! Advanced API, Actuator, Plugin, SO

Hi Ayman, Thanks for your reply. About the removal of all actuators except muscles, residuals and GRF; How come PointActuators do appear in the results of a StaticOptimization? Are they then somehow considered as residuals? The New Actuator was only added in the model file. I did not specify anythin...
by Erik Dijkstra
Mon Jan 26, 2015 7:37 am
Forum: OpenSim
Topic: URGENT! Advanced API, Actuator, Plugin, SO
Replies: 7
Views: 2117

URGENT! Advanced API, Actuator, Plugin, SO

Hi support, I am trying to implement a new type of PointActuator (I call it: PointGRFActuator) that has an extra position and velocity factor that adjusts the amount of force it can produce. The position factor is from an exponential function using the vertical distance between the PointGRFActuator'...
by Erik Dijkstra
Thu Sep 25, 2014 12:18 am
Forum: OpenSim
Topic: PointActuator location as event trigger in a simulation
Replies: 0
Views: 250

PointActuator location as event trigger in a simulation

Dear all, Is there a way to access the information(through API) on the location of a PointActuator? When creating the PointActuator you can set the location, 'point', which I would like to use in an event trigger to change the optimal force of the actuator if it crosses a certain plane. Best regards...
by Erik Dijkstra
Wed Aug 27, 2014 2:48 am
Forum: OpenSim
Topic: Inverse Dynamics Algorithm
Replies: 0
Views: 323

Inverse Dynamics Algorithm

Hi, I was wondering what kind of algorithm is used in the Inverse Dynamics tool. When looking at the code it seems like a least squares static optimization method. Is it the same as described by Kuo, A least-squares estimation approach to improving the precision of inverse dynamics computations in J...
by Erik Dijkstra
Thu May 15, 2014 10:52 am
Forum: OpenSim
Topic: SimmSpline data interpolation 100 to 1000Hz
Replies: 0
Views: 306

SimmSpline data interpolation 100 to 1000Hz

Hi all, I am trying to spline fit kinematic data to get it with a sample frequency equal to the ground reaction forces (1000Hz) but I am not succeeding very well with this. I think I successfully managed to create the simmsplines with the following SimmSpline rSpline, lSpline; for(int i=1; i<MTime.g...
by Erik Dijkstra
Fri Mar 14, 2014 9:11 am
Forum: OpenSim
Topic: developer guide for static optimization
Replies: 2
Views: 523

Re: developer guide for static optimization

Hi Yoann,

You could have a look at the source code of OpenSim and perhaps also SimBody. In the source code you can find the cpp files that are used for the StaticOptimization in OpenSim, and more general the Optimizer in SimBody.

Best regards,
Erik