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Assignment

Modified 2018-08-28 by Josh Roy

Configuration Space

Modified 2018-08-28 by Josh Roy

1.1. Imagine an arm moving in three dimensions with three joints, \theta_1 and \theta_2 , and \theta_3 . What is the configuration space?

1.2. Imagine a 1.5\mbox{m} diameter circular robot moving in a room with four walls, one at x=-20 , a second at x=30 , a third at y=-10 and a fourth at y=0 . The robot’s position is indexed at its center and it is omnidirectional (that is, it can move in any direction without turning). All these coordinates are in meters. What is the robot’s configuration space?

Manual Motion Planning

Modified 2018-08-31 by Josh Roy

The following problems will use the arm.py code(in the Github Classroom). First we ask you to perform motion planning manually. This is surprisingly useful for understanding the robot’s degrees of freedom and what it can do. It is also notable that manual motion planning is how the Canada Arm on the International Space Station is used today. They check each plan manually and tweak it by hand, because collisions between the arm and the station would be catastrophic.

  1. Move the arm from its start location to as close as possible to x=8, y=0 so that it does not collide with the circle. Describe how you had to move the arm in words (for example using words like clockwise and counter clockwise) and also submit four images showing the sequence of positions the arm went through.

Implementing the RRT

Modified 2018-09-29 by Theo Guerin

Implement the skeleton methods for a 2d RRT in python following this paper and rrt.py(found in the Github Classroom).

Use the RRT to find a motion plan for a 2d robot for the same point as above. The r key starts running the RRT to expand it, and then pressing r again stops it from expanding.

3.1. First run the RRT for a second or two. Describe in words what the RRT does, and submit four images showing its intermediate progress.

3.2. Now run it for a long time, 10 or 20 seconds. Describe in words what the RRT does, and submit four images showing its intermediate progress.

3.3. The motion of the robot with the RRT should differ from your planned motion/ideal motion. Does it find the shortest path of the arm to the goal? Why or why not?

3.4. How does the motion of the robot with the RRT when run for a short time differ from when run for a long time?

Handin

Modified today by sageshoyu

When you are done, use this link to create your Motion Planning Github Repo. Commit and push the relevant files:

  • answers.md
  • All images, named by question number and
  • Any python files that you implemented your RRT