Using the Stick to Collect Data

Things to consider

The following are good tips to keep in mind. You don't have to follow them very judiciously.

1. Have a lot of variations to the data. We encourage collecting around 20-25 demonstrations per task and environment. Try to make each demonstration different from the other. Ideally vary the starting points as shown in the graphic below.

   

   Starting from a grid to collect demos.
2. Make sure the relevant objects are always visible in the frame while collecting the demos. The relevant objects can be the door/ door handle for task “Door Opening”, or the object you have to pick (Eg: Cup) in the task “Pick and Place”. This is usually helpful for visual servoing policies.

3. Another thing to keep in mind while collecting demos is to make sure to start and stop recording the demo at the right times. Ideally, you would want to start recording just before starting the demo and stop recording immediately after the demo is finished.

4. Be aware of the limitations of the robot while collecting demos. For example as humans we may be able to operate around tight spaces using the stick but the robot may not due to its base/ arm not being as flexible. Also tasks that may require long extension of arm can also be limiting since the hello-stretch’s arm can only extend for so long. Always good idea to double check the robots capabilities before collecting demos to avoid wasting time on trajectories that are just not possible to run on the hardware

5. Finally while recording the demos, try to keep your motion as smooth and stable as possible. Try to avoid shaking or having any noisy movements during the demos.

How to collect demos

1. Video Link explaining how to collect demonstrations: Video link

2. Make sure the iPhone is installed in the correct orientation. When holding the stick straight, the camera lens should be on the bottom right side.

   

   This is how the stick should look when the camera is installed right.
3. Make sure the camera mount is roughly at 75 degree tilt from the horizontal stick axis to get the same distribution of data as in HoNY. To confirm this tilt you can use iPhone app called Precise Level.

   

   iPhone holder tightened at approximately 75 degrees.
4. Steps to collect 1 trajectory demo:

   1. Open the Record3D app and go to "Record" panel

   2. Align your stick to the appropriate “starting” orientation and position for the trajectory.

   3. Press the “Red” record button to start recording and immediately start moving the stick according to your demonstration.

   4. Once the demonstration is complete, immediately press the “Red” button to stop recording

5. Repeat the above for multiple demonstration with varying starting positions and trajectory motions