YoComposite

What is a YoComposite?

A YoComposite is an abstract data structure composed of several YoVariables, for more information on YoVariables YoVariable wiki, which can represent a more complex type of data such as a 2D or 3D point.

A YoComposite is attributed a name and a pattern, following the example of a 3D point composite, the name would be Point3D and the pattern would be: x, y, and z. Using the pattern, SCS 2 can then search throughout all the control variables to retrieve any set of YoVariables that represents a Point3D, allowing then direct interaction with a point rather than its coordinates.

By default, SCS 2 defines a small set of predefined YoComposites that are:

• YoTuple2D representing any 2D points and vectors. It uses the following pattern: x, and y.
• YoTuple3D representing any 3D points and vectors. It uses the following pattern: x, y, z.
• YoQuaternion representing any unit-length quaternion. It uses the following pattern: qx, qy, qz, and qs.
• YoYawPitchRoll representing any orientation described as the yaw, pitch- and roll angles. It uses the following pattern: yaw, pitch, and roll.

The use of YoComposites instead of YoVariables when searching control variables greatly reduces the size of the search result.

Search example when searching for YoVariables:

Same keywords but searching for YoTuple3Ds:

How to create a new YoComposite?

SCS 2 comes an editor for creating new YoComposites accessible from the menu:

This open the following dialog:

Let's create a new YoComposite for the spine joints of Atlas. Start by clicking Add...:

Enter the name of composite, we will call it Spine in this example:

The names for the joints are: back_bkz, back_bky, and back_bkx which is what we will use for the component identifiers, i.e. the pattern of the composite. Add the identifiers using the "plus" button:

and name them after each joint to obtain the result:

Now save:

The new composite is now available in the search panel:

Note the check for enabling cross-registry search:

This optional feature, when enables, consider `YoComposite`s that have their components registered across multiple `YoVariableRegistry`s. This feature however is more computationally expensive especially for composites with a few identifiers which is why it is disabled by default.

Additional features available with YoComposite

In addition to enable searching for composites, a YoComposite can also declare a preferred chart configuration that simplifies the process of plotting multiple YoVariables. Going back to our example with the spine composite for Atlas, open the composite editor dialog and add a preferred chart configuration:

Let's name this first configuration "Horizontal":

Modify the column field for each component as follows:

Now save the modifications and close the editor. Create 3 charts:

Search for any spine composite, then drag and drop a composite in the first chart:

Additional preferred configurations can be added to the same YoComposite in which case when plotting the composite a popup window will request which configuration to use:

Save/Load YoComposite

Upon closing the application, SCS 2 will automatically saves your custom YoComposite patterns such that the next time a session for the same robot and same controller is opened, they are automatically loaded. You can find the save file in: /home/SCS2/Configurations/RobotName/ControllerName/YoComposite.scs2.yoComposite.

However, if desired, YoComposite patterns can be saved at any moment: