LookAt¶

level_1

Goal - Make Pepper look at a specific location with his head and his mobile base.

// Get the target frame to look at.
val targetFrame: Frame = ...

// Build the action.
val lookAt: LookAt = LookAtBuilder.with(qiContext)
                             .withFrame(targetFrame)
                             .build()

// Run the action asynchronously.
val lookAtFuture: Future<Void>? = lookAt?.async()?.run()
// ...
// Request cancellation to stop the execution.
lookAtFuture?.requestCancellation()

// Get the target frame to look at.
Frame targetFrame = ...;

// Build the action.
LookAt lookAt = LookAtBuilder.with(qiContext)
                             .withFrame(targetFrame)
                             .build();

// Run the action asynchronously.
Future<Void> lookAtFuture = lookAt.async().run();
// ...
// Request cancellation to stop the execution.
lookAtFuture.requestCancellation();

Typical usage - You want Pepper to look at something/someone and track it.

How it works¶

Looking at a location¶

To configure where Pepper should look at, use a Frame.

Get a Frame and build the LookAt action with it:

val targetFrame: Frame = ...

val lookAt: LookAt = LookAtBuilder.with(qiContext)
                           .withFrame(targetFrame)
                           .build()

Frame targetFrame = ...;

LookAt lookAt = LookAtBuilder.with(qiContext)
                             .withFrame(targetFrame)
                             .build();

You can refer to the Frame reference page to see how to get a Frame.

Note

Pepper will track the target frame while the action is running. For example, if the target frame is a Human head frame, and the human moves with respect to the robot, Pepper will automatically update his posture to keep looking at the human.

Setting the movement policy¶

When Pepper looks at a location, you can choose if he should use only his head or also move his mobile base by setting the LookAtMovementPolicy.

By default, the LookAtMovementPolicy is set to HEAD_AND_BASE, but it can be set to HEAD_ONLY.

If you choose HEAD_ONLY, Pepper will only turn his head to look at the specified Frame. However, if you use HEAD_AND_BASE, Pepper will be able to also turn his base.

val lookAt: LookAt = ...
lookAt.policy = LookAtMovementPolicy.HEAD_AND_BASE

lookAt.async().run()

LookAt lookAt = ...;
lookAt.setPolicy(LookAtMovementPolicy.HEAD_AND_BASE);

lookAt.async().run();

Managing base availability¶

If you run a LookAt action with the movement policy set to HEAD_AND_BASE while the robot base is not available, the action execution will fail and throw an exception. In that case, you can try to set the movement policy to HEAD_ONLY and rerun the LookAt action.

Use cases¶

Track a human¶

To make Pepper track a Human:

Step	Action
	Get the human head `Frame` (see Human).
	Build the `LookAt` action with it.

Performance & Limitations¶

Animate or LookAt?¶

You can make Pepper move his head and turn himself with both Animate and LookAt.

Use Animate to perform a constant movement with no variation except for obstacle avoidance.
Use LookAt to create a dynamically adaptive movement based on a target.