README.md

Assignment 03

Using inverse kinematics

• Start the MoveIt Noetic container for a UR3e on your laptop
• Use the RosClient to load the robot
• Taking a robot and a list of frames as parameter, calculate a feasible configuration for each of the frames
• Try to find an optimal start_configuration for each so that the motion from one config to the next is minimized
• Store all found configurations in a JSON file using compas.json_dump or compas.json_dumps
• Commit the assignment_03.py AND the assignment_03.json file in your submission

How to start

Use the following code as a starting point for your assignment:

"""Assignment 03: Using inverse kinematics
"""
import os
import compas
from compas_fab.backends import RosClient
from compas_fab.robots import Configuration

from compas.geometry import Frame
from compas.geometry import Point
from compas.geometry import Vector


# Step 1: Inside this function, complete the main part of the solution for the assignment:
#  - Taking a robot and a list of frames as parameter, calculate a feasible configuration for each of the frames
#  - Try to find an optimal start_configuration for each so that the motion from one config to the next is minimized
def calculate_ik_for_frames(robot, frames):
    configs = []
    # ...
    return configs


# Step 2: store all found configurations in a JSON file using compas.json_dump or compas.json_dumps
def store_configurations(configurations, filename):
    # ...
    pass

# Use the following to test from the command line
# Or copy solution_viewer.ghx next to the folder where you created assignment_03.py to visualize the same in Grasshopper
if __name__ == '__main__':

    frames = [
        Frame(Point(-0.329, 0.059, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(-0.260, 0.129, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(-0.186, 0.194, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(-0.106, 0.252, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(-0.020, 0.299, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(0.074, 0.329, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(0.172, 0.330, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(0.263, 0.295, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(0.339, 0.233, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(0.400, 0.155, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000)),
        Frame(Point(0.448, 0.070, 0.082), Vector(1.000, 0.000, 0.000), Vector(0.000, -1.000, 0.000))]

    # Loads the robot from ROS
    with RosClient('localhost') as client:
        robot = client.load_robot()

        # Step 1: calculate IK solutions for each frame
        configurations = calculate_ik_for_frames(robot, frames)
        print("Found {} configurations".format(len(configurations)))

        # Step 2: store all configurations in a JSON file
        filename = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'assignment_03.json')
        store_configurations(configurations, filename)
        print("Stored results in {}".format(filename))

Expected result

How to submit your assignment

1. You should have forked this repository last week, if not, check assignment submission instructions in lecture 02.

2. Make sure your local clone is up to date

   (fs2022) git checkout main
   (fs2022) git pull origin
   

3. Use a branch called assignment-03 for this week's assignment

   (fs2022) git checkout -b assignment-03
   (fs2022) git push -u assignments assignment-03
   

4. Create a folder with your name and last name, eg. david_bowie (make sure it is inside the current assignment folder)

5. Create a Python file named assignment_03.py and paste the starting point code.

6. For visual inspection, copy the file solution_viewer.ghx in the same folder of your assignment_03.py.

7. Solve the coding assignment and commit both the Python file and the JSON file

   (How do I commit?)

   Usually, commits are done from a visual client or VS code, but you can also commit your changes from the command line:

   (fs2022) git add lecture_04/assignment_03/david_bowie/\* && git commit -m "hello world"
   

8. Once you're ready to submit, push the changes:

   (fs2022) git push assignments
   

9. And create a pull request (What's a pull request?)

   1. Open your browser and go to your fork
   2. Create the pull request clicking Compare & pull request and follow the instructions