# Tag Info

### why is quadrotor motion planning hard?

The main problem with motion planning is the time-dimension. Not only that the UAV can move up, down, forward or backward, but the motion is also defined along the time-axis. A motion plan like "up, ...
1 vote

### How to access the true ROS cost map boundaries instead of defaultones?

I think you are confused about the coordinate system that is being used. Please read http://wiki.ros.org/costmap_2d, particularly sections 7 and 8.1.4. Assuming your global costmap is initialized in ...
• 946
1 vote

### Does RRT perform graph search?

I would argue, that it is not graph search. In the implementation, you keep all the nodes in a flat list and check which of the nodes is closest to the sampled point. As all nodes are checked, this ...
• 6,682
1 vote

### Arm path planning with obstacle avoidance in Unity

The steps you have identified are correct. You will need an IK solver if you want to plan in Cartesian space. Cyclic Coordinate Descent is one OK option if you always solve for points which are ...
• 6,682
1 vote

### RRT star Convergence

No, at every iteration your RRT* should give a more optimized path once it has found it. The fluctuations are strange. You should try to get a convergence similar to this one.
• 156
1 vote
Accepted

### How to plan path for robotic arm with RRT?

Maybe there is a bit of misunderstanding about iterative methods for solving IK problems. Actually, an iterative IK solver does not necessarily require timestamps (or anything related to time). The ...
• 1,859
1 vote

### Do the distance function and steering function in an RRT have to be related?

I asked this question on OMPL's mailing list. OMPL is an very popular motion planning library. Here is the response: https://sourceforge.net/p/ompl/mailman/message/35918890/ The answer is yes, they ...
• 111
1 vote

### How to make RRT to work for dynamic systems?

Dynamic Systems are described via system identification. That is a procedure to generate a physic engine on-the-fly. The physic engine can predict the future state of the system. An example: the ...

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