Search found 8 matches

by allan
Wed Sep 08, 2021 8:49 pm
Forum: PyBullet Support and Feedback
Topic: Simple model not working, please help
Replies: 2
Views: 5289

Re: Simple model not working, please help

Since torque control of the motor is not working, as a workaround I can calculate the expected acceleration from the torque, integrate for the velocity, and use velocity control of the rotor. I am using this in another application (not the one I posted above), where I calculate the torque from aerod...
by allan
Wed Sep 08, 2021 6:16 pm
Forum: PyBullet Support and Feedback
Topic: Simple model not working, please help
Replies: 2
Views: 5289

Re: Simple model not working, please help

Problem partly solved. I had not used the URDF_USE_INERTIA_FROM_FILE flag in loadURDF, so PyBullet was defaulting to an inertia tensor of zero. When I included the flag, I got an error message "Bad inertia tensor properties, setting inertia to zero for link", apparently because in my URDF ...
by allan
Tue Sep 07, 2021 1:50 am
Forum: PyBullet Support and Feedback
Topic: Simple model not working, please help
Replies: 2
Views: 5289

Simple model not working, please help

I have created an extremely simple model of a rotor rotating around the z-axis. The base link is a heavy rectangular box, the rotor is a single link representing two opposing rotor blades, and there is a continuous joint with a vertical axis between the links. When I use velocity control of the join...
by allan
Mon Aug 30, 2021 4:34 am
Forum: General Bullet Physics Support and Feedback
Topic: Problem simulating an autorotating rotor
Replies: 2
Views: 2220

Re: Problem simulating an autorotating rotor

Unfortunately, this did not solve the problem. At first I thought that it had, but then I realized that I had reverted the program back to velocity control, and when I go back to torque control I still can't get an angular velocity greater than 81 rpm (which is a lot less than 100 radians/sec anyway).
by allan
Sun Aug 29, 2021 7:50 pm
Forum: General Bullet Physics Support and Feedback
Topic: Problem simulating an autorotating rotor
Replies: 2
Views: 2220

Re: Problem simulating an autorotating rotor

I did some more searching and found a possible answer on this forum. By default, the maximum angular velocity of a joint is limited, with the default limit being 100 radians/sec. This can be changed using:
p.changeDynamics(body_name, joint_index, maxJointVelocity=10000)
I'll give this a try
by allan
Sun Aug 29, 2021 5:42 am
Forum: General Bullet Physics Support and Feedback
Topic: Problem simulating an autorotating rotor
Replies: 2
Views: 2220

Problem simulating an autorotating rotor

I am trying to build a model rocket that would land by deploying free-wheeling rotor blades from its nosecone, rather than the usual parachute, basically converting the rocket into a gyro-glider under radio control. I have worked out the basic aerodynamics of the rotor blades, and created a simple s...
by allan
Fri Jul 30, 2021 5:13 pm
Forum: PyBullet Support and Feedback
Topic: Can't modify the example .urdf files
Replies: 1
Views: 3819

Re: Can't modify the example .urdf files

I found the problem. During installation of PyBullet, the "pybullet_data" folder apparently gets copied into
"\Users\<myname>\AppData\Roaming\Python\Python39\site_packages\", which is where the files get loaded from. Now I can edit the files.
by allan
Wed Jul 28, 2021 6:10 pm
Forum: PyBullet Support and Feedback
Topic: Can't modify the example .urdf files
Replies: 1
Views: 3819

Can't modify the example .urdf files

I am getting started with PyBullet on Windows 10. I entered the "Hello PyBullet World" script from the Quickstart Guide and it runs fine, using the r2d2.urdf file. When I tried running it using other sample .urdf files from the pybullet_data folder, that also worked. But when I created my ...