Recent Activity

Dongho Kang posted a new thread.

Energy conservation of robot simulation.

Hello, I am trying to simulate 18 DOF quadrupedal robot (the model is as the following image) using MuJoCo. (GUI was developed by...

Forum: Simulation

Emo Todorov replied to the thread Include wrl file in mujoco model.

You should include the STL files in assets, and then create a mesh geom for each STL file and attach all of them to the same body. The...

Emo Todorov replied to the thread Simulating a nima 17 stepper motor.

MuJoCo does not have a native actuator type to simulate such effects. You could approximate it with a position actuator, and then when...

Emo Todorov replied to the thread Center of mass jacobian.

Yes, this is how you do it.

Emo Todorov replied to the thread How to create pure torque source? d->qfrc_applied and d->ctrl.

Assuming you define a motor (so that d->ctrl corresponds to force) the two approaches are equivalent.

Emo Todorov replied to the thread Penetration of Objects when Controlling a Robot with Mocap.

mocap body positions are treated as constants by the simulator, even though you can change them at runtime. So if you set the mocap...

Emo Todorov replied to the thread Change the gravity for some bodies on the model.

Gravity is the same for all bodies. However you can add external forces to each body that compensate for gravity, using xfrc_applied.

Emo Todorov replied to the thread URDF with compile.cpp.

The joints in MuJoCo define a kinematic tree. If you want to have loop joints, you should add them as equality constraints. So in order...

Emo Todorov replied to the thread Modelling Human Muscles.

Currently there is no default muscle model, but it will be added eventually. Importing from OpenSim is complicated because the OpenSim...

Emo Todorov replied to the thread Error of kinematic positions.

How exactly are you computing your CoM (p_G)? subtree_com is the CoM of each subtree, so I am guessing you are comparing to a different...

Emo Todorov replied to the thread How to fix some joints and only allow other joints to move.

Not quite sure what you mean (and I cannot load your model because STL files are missing), but in general you can restrict the motion in...

Emo Todorov attached a file to the thread Trouble with a closed Kinematic loop.

Looks like you connected the bodies at the wrong place. The red sphere in the image shows your anchor point. There is a model of this...

Emo Todorov replied to the thread Camera sensor in mujoco model.

You can define model cameras with the <camera> element in the XML. Then at runtime, you have to switch to rendering from the model...

Emo Todorov attached a file to the thread Modeling Wheels - Troubleshooting.

There were several issues with your model - you specified very low geom density (5, while the density of water is 1000) resulting in a...

Emo Todorov replied to the thread PID actuator.

If you are not sufficiently familiar with MuJoCo's actuation model, it may be easier for you to simulate a PID controller in your code,...