## Search found 14 matches

Thu May 09, 2019 5:29 pm
Forum: PyBullet Support and Feedback
Topic: Position control for robot base?
Replies: 13
Views: 9053

### Re: Position control for robot base?

"However, when comparing read vs. sent velocities at the base, they were constantly downscaled by a factor of 5, and rotations around x and y had to be multiplied by -1 to make them comply with the right-hand-rule." Maybe you can add a small piece of code with the strange behavior you see. Preferab...
Wed Mar 06, 2019 5:33 pm
Forum: PyBullet Support and Feedback
Topic: Position control for robot base?
Replies: 13
Views: 9053

### Re: Position control for robot base?

If you want to give velocities and angular velocities instead of position and orientation, then I think you can calculate the position and orientation in the next time step from your velocities and angular velocities and the time step duration (delta_t) . e.g.: x_new = x_current + delta_t* x_velocit...
Sun Jan 20, 2019 5:31 pm
Forum: Applications, Games, Demos or Movies using Bullet
Topic: Pybullet: A dog robot and a spinning top
Replies: 2
Views: 4212

### Re: Pybullet: A dog robot and a spinning top

I found some interesting work on hopping robots which are a good step towards naturally walking robots. So I created a hopper in PyBullet:
Hopper.JPG (42.33 KiB) Viewed 3343 times
Sat Nov 17, 2018 2:16 pm
Forum: PyBullet Support and Feedback
Topic: Varying the center of mass of an object
Replies: 3
Views: 3128

### Re: Varying the center of mass of an object

A not-so-elegant solution may be to add a fixed-linked cube to you mesh object and position it inside the mesh-object. You can then position it where you want the center of mass to be. Then you give almost all the mass to that little cube and reduce the mass of the mess-object. Your moments of inert...
Sun Nov 11, 2018 3:04 pm
Forum: PyBullet Support and Feedback
Topic: Realistic tri-axial-accelerometer behavior for Inertial Measurement Unit
Replies: 3
Views: 2102

### Realistic tri-axial-accelerometer behavior for Inertial Measurement Unit

Many legged robots have Inertial Measurement Units (IMU's) on them to determine whether they are falling over or other. Usually these IMU's have accelerometers in them to determine the direction of gravity. This gravity direction is then be used to work out the robot tilt angle. For Pybullet models ...
Sun Nov 11, 2018 2:30 pm
Forum: PyBullet Support and Feedback
Topic: Rotate Object to Face Origin/Point
Replies: 1
Views: 1857

### Re: Rotate Object to Face Origin/Point

I would do the same as you using the spherical coordinates and then transform to quaternion. I found however that with the Euler angles the order of the angle operations is important (first roll around the world-x, then yaw around the world-z, finally pitch around the world-y). In addition for the r...
Sun Nov 04, 2018 12:53 pm
Forum: Applications, Games, Demos or Movies using Bullet
Topic: Procedural Destruction of convex shapes.
Replies: 4
Views: 4047

### Re: Procedural Destruction of convex shapes.

Your work became a lot clearer to me when I had a look at more of your videos on Youtube. I assume you want to make a nice 3D version of Flank-that-Tank. I think it would be cool especially if you use cool camera angles from outside the tank and not just first person from inside the tank. Personally...
Sun Oct 14, 2018 4:05 pm
Forum: PyBullet Support and Feedback
Topic: Defining a Kinematic Object
Replies: 2
Views: 1777

### Re: Defining a Kinematic Object

I'm not sure, but I noticed that setting an objects mass to zero results in the object staying fixed to its environment. You can still change its position but apparently according to some other post if you use "resetBasePositionAndOrientation" for that it will be a none physical change: https://pybu...
Sat Oct 06, 2018 6:59 pm
Forum: Applications, Games, Demos or Movies using Bullet
Topic: Pybullet: A dog robot and a spinning top
Replies: 2
Views: 4212

### Re: Pybullet: A dog robot and a spinning top

I'm also trying to make a robot that can walk up the stairs using Arduino, toy motors etc. PyBullet allowed to make a quick model.
A 3-minute video showing the very simple code and modeling result is here:
Mon Oct 01, 2018 6:00 pm
Forum: PyBullet Support and Feedback
Topic: Use mouse to control camera view in opengl window
Replies: 4
Views: 4658

### Re: Use mouse to control camera view in opengl window

Yes that works great! I definitely thought I had tried that before without result but apparently not.
Fri Sep 28, 2018 5:41 pm
Forum: PyBullet Support and Feedback
Topic: Use mouse to control camera view in opengl window
Replies: 4
Views: 4658

### Re: Use mouse to control camera view in opengl window

I think most of us have found the same issue and then turned to programmatically work around it. I think it will be improved in a future version. Hope the example below helps you a bit further. Example of moving the camera around programmatically with the keys (not the mouse sorry) while staying dir...
Fri Sep 28, 2018 5:29 pm
Forum: PyBullet Support and Feedback
Topic: Programmatically create a multi-body chain
Replies: 2
Views: 3079

### Re: Programmatically create a multi-body chain

Not sure I understand it perfectly but I maybe my example video: https://www.youtube.com/watch?v=F-Pj9AV6wfo can help you. The sourcecode is found at https://github.com/richardbloemenkamp/Robotdog/blob/master/robotdog.py . Basically I use extra small objects as joint elements. There may be better wa...
Fri Sep 28, 2018 5:15 pm
Forum: PyBullet Support and Feedback
Replies: 6
Views: 3288

### Re: Car Simulation for Radar

Your story is a bit complicated to me and maybe some code would clarify. I have experienced difficulties myself with torque driven motors. I tried a few work arounds, played with various friction components, but still my torque motor did not meet perfectly with analytical calculations. If you do not...
Tue Sep 18, 2018 7:59 pm
Forum: Applications, Games, Demos or Movies using Bullet
Topic: Pybullet: A dog robot and a spinning top
Replies: 2
Views: 4212

### Pybullet: A dog robot and a spinning top

All,

Just to let you know I had some fun with Pybullet creating keyboard controlable 4-leg dog robot and a spinning top. Both with free-to-use single file source code.