These sample skills will walk you through different features of the Jibo SDK Behavior Editor. Each sample builds on the previous one, so make sure to do them in order. Refer to the Jibo SDK Documentation for further tools usage and API reference.
You will need a GitHub account and an SSH key to clone this repository.
If you downloaded a ZIP file of the sample code, unzip it and skip to Step 2.
git clone git@github.jibo.com:sdk/sample-code.git
cd ~/<path>/sample-code
npm install
atom .
If you don't npm install, the Behavior Tree Tool cannot render the behaviors!
- Press cmd-r (Macs) or ctrl-r (PCs) to run the sample behavior tree in the Jibo simulator.
- To view the debugger, press cmd-opt i (Macs) or ctrl-alt-i (PCs), or click View > Developer > Developer Tools.
- Press cmd-r (Macs) or ctrl-r (PCs) to stop the simulator.
- Open the
sample-codeskill in Atom.
- If you don't see the Project pane, click View > Toggle Tree View to open it.
-
Click src > main.js in the Project pane to open the skill's main.js file.
-
Change the following line of code from:
let root = factory.create('../behaviors/01-sequence');to
let root = factory.create('../behaviors/xx-behavior-tree-name);where
xx-behavior-tree-nameis the name of the next behavior tree.
Plays two animations in sequence.
Plays an animation and an audio file in parallel.
Animations (.keys files) have the ability to dispatch generic events at specific keyframes.
An Event layer is included in animations/greeting-with-event.keys. Click the keyframe at frame 30 on the Event layer; you'll see that it is set to dispatch an event called blink in the Name property. The animation system dispatches the event on an emitter that the StartOnAnimEvent decorator is listening for. This decorator will start the PlayAudio behavior when the blink event is heard.
This allows a developer to synchronize logic with exact keyframes in an animation.
A WhileCondition is a decorator that restarts a behavior that succeeds if a condition is met. In this example, the WhileCondition is restarting a sequence that plays two animations. Since the WhileCondition decorator always succeeds, these animations are played forever in sequence.
In this example, the WhileCondition decorates a PlayAnimation behavior directly. It creates a self.count variable in its initialization function and decrements the variable each time its condition function is called. When the conditional returns false (self.count is not 0), the WhileCondition allows the PlayAnimation behavior to succeed and a sound is played. As soon as self.count is decremented to 0, the PlayAnimation stops repeating.
The LookAt behavior has two modes. In this example, the behavior is set to single-shot mode, which means that getTarget is called once and the behavior succeeds once Jibo does a best-effort look at that target. TimeoutJs is a behavior that does nothing for an amount of time. The whole sequence is repeated.
In this example, LookAt is set to continuous mode. This means that getTarget will be called every frame to ask for a new target. In this mode, the behavior never succeeds; it always remains in progress until a decorator forces it to succeed or fail, or if a parent explicitly stops it.
This sample is similar to example 06. In this example, the LookAt sequence executes in parallel with an other sequence that makes Jibo blink at random intervals.
A Switch allows for branching logic within behavior trees and operates similar to a switch/case statement. The Switch attempts to play its children in sequence until one succeeds. The Case decorator fails a behavior before it has started if its conditional returns false, forcing the Switch to move on to its next child.
In this example, an ExecuteScript behavior sets a property on notepad that the Case decorators check against. One of two animations will be played.
A Subtree allows for encapsulation within other behaviors trees. They treat a whole .bt file as a single behavior.
The getNotepad argument allows a parent tree to pre-populate a Subtree's notepad, allowing a behavior trees to pass arguments to a subtree. The behaviors/10-subtrees/choose-animation.bt plays an animation according to a property on its notepad, which is set by its parent tree.
Subtrees can also return results. Every tree has a result object scoped to a single .bt file. Any function argument can add properties to this object. When the subtree returns, its parent tree gets that result object. This is how behavior trees deal with return values. If, for example, you had subtree called get-persons-name.bt, that subtree might be highly complex and encapsulate a range of behaviors, such as voice recognition, facial identification, and text-to-speech. From the point of view of the parent tree, the mechanism by which that subtree obtains a person's name is a black box, but the end result is that that subtree returns the appropriate information.
SucceedOn decorators force a behavior to succeed. They may force success from an event emitted from an animation or emitter, a conditional, or a timeout. More sophisticated SucceedOn decorators might succeed a behavior if Jibo hears "Hey Jibo" or any arbitrary parsed rule.
In this example, there are three subtrees that all point to the idle behavior tree, which never succeeds unless decorated or explicitly stopped by a parent. The first subtree succeeds after 5 seconds, and then the robot zeros itself, blinks, and plays a sound. The second subtree succeeds when an event is emitted from the emitter object, available globally. The third subtree saves its start time and forces success after a period of time has passed.
Decorators can also control when a behavior starts.
StartOnAnimEvent was introduced in example 3, and prevents its behavior from starting until an event is dispatched from an animation.
StartOnCondition is the most generic and flexible of the StartOn decorators, and will only start a behavior when the condition argument returns true. In this example, the PlayAudio behavior is started after a random amount of time between 2 and 6 seconds. The second PlayAudio behavior only starts after the start event is emitted from the global emitter.
In addition to the built-in behaviors and decorators included in the Jibo SDK, developers can create their own custom ones. A custom behavior consists of two parts: the behavior code (src/behaviors/center-robot.js) and the schema (schema/center-robot.json). You must also require the behavior JavaScript file after jibo.init returns. See src/main for details.
In this example project, a custom behavior called CenterRobot is included. This behavior will center the robot either globally or locally. Globally centering Jibo will face him away from his cord in the back. Locally centering him will make Jibo sit upright in whatever direction he last procedurally looked at. In behaviors/13-custom-behaviors.bt, the robot first looks right, then it centers globally, then looks right again, and then centers locally.
Developers can also create custom decorators. In this example, SucceedOnTouch will force a behavior to succeed when Jibo's face is touched. In the simulator, click directly on Jibo's face to simulate touch input.
Decorators are very similar to behaviors in how to code them and hook them up. The biggest difference is is the update function:
A behavior only needs to return a status to the behavior tree engine.
update() {
return Status.IN_PROGRESS;
}
When the engine runs its update cycle, it first updates the behavior before updating its decorators. The result of the behavior is passed into the update function of its decorators. Each decorator then has the opportunity to modify or change the status of the behavior its decorating:
update(result) {
if(this.doForceSuccess) {
return Status.SUCCEEDED;
}
return result;
}
update(result) {
if(result === Status.SUCCEEDED) {
return Status.FAILED;
}
else if(result === Status.FAILED) {
return Status.SUCCEEDED;
}
return result;
}
Multiple decorators can be added to one behavior. The engine first updates the behavior, then updates the decorators in order from top to bottom. The first decorator to return either Status.FAILED or Status.SUCCEEDED wins, and all decorators on that behavior are stopped.
In this example, a subtree is decorated with both a FailOnTouch and SucceedOnTouch decorator. The subtrees are under a Sequence and a Switch. In order for RobotCenter1 to be executed in the Sequence, the sibling above it must finish with Stats.SUCCEEDED. Since SucceedOnTouch is first, it wins, and succeeds the subtree. In order for CenterRobot2 to be executed in the Switch, the sibling above it must finish with Status.FAILED. (Remember that Switch executes its children in order until one succeeds.) Since FailOnTouch is first, it wins, and fails the subtree, allowing the robot to center.
A Switch will play all of its behaviors in sequence until one succeeds.
Jibo can listen for speech through Audio Speech Recognition (ASR). He has two types of listening capabilities:
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The first is embedded phrase-spotting. Phrase-spotting tends to be faster and more accurate, but is quite limited in what it can listen for. For now, Jibo only has one phrase he can spot: "Hey Jibo".
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The second is cloud-based, which can listen for any arbitrary speech, but tends to take a bit longer to process than the embedded type.
In this example, Jibo idles until he hears "Hey Jibo," at which point he centers himself and does an excited dance. The SucceedOnEmbedded decorator forces the idle subtree to succeed when Jibo hears "Hey Jibo".
Launch the simulator, click on the Chat tab, and type Hey Jibo in the Speak to Jibo here box, press enter, and watch him dance. Jibo will hear Hey Jibo even if you type other things before and afterwards. If you type Hey Jibo and continue typing, he will hear it as soon as you enter a space.
This is a small interaction where you ask Jibo to make a reservation. The Listen behavior points to the order.rule file. Rule files are explained in the Speech Recognition section of the developer documentation. You can test the rule in the .rule file Test pane by typing the following:
please reserve me a flight to boston massachusetts
The test should return the following:
{
"Input": "please reserve me a flight to boston massachusetts",
"NLParse": {
"state": "ma",
"book": "air",
"city": "boston"
},
"heuristic_score": 36
}
The Listen behavior in the behavior tree will listen for any strings that match the rule created in the order.rule file. The Listen behavior is in parallel with a sequence of an idle behavior and an ExecuteScript that centers the robot and turns on the LED. In the Listen behavior, Jibo listens for a 'hey-jibo' event and dispatches the 'listen' event that calls order.rule, which triggers the SucceedOnEvent decorator.
When the Listen behavior gets a valid NLParse, notepad.results is set, which is later used in the TextToSpeechJs behavior to produce a response.
.bt files get transpiled to JavaScript files through behaviorify/register at runtime. Since they are JavaScript, they can require external .js files like any other node module. While function arguments are very useful as the glue that helps behaviors and decorators communicate, having too much code in a single argument can be cumbersome. In these circumstance, refactoring the code into an external file can help.
This behavior tree contains an ExecuteScript which requires src/look-and-dance.js. This file blends a static and a procedural animation. This animation combines a continuous mode LookAt that fixes Jibo's eye on one point while looping a dance animation on his body DOFs. Once the dance is over, the LookAt instance is stopped and the callback is called. In the behavior tree, the success callback is executed, the robot centers, and the tree returns with Status.Succeeded.
In this example, we access Jibo's Local Perceptual Space to continuously look at a moving target (face) in the environment. We begin by calling jibo.lps.getClosestVisualEntity() to get the closest item that Jibo believes is a human. This gives us back an Entity object.
From this object, we extract the position of the closest visual entity. Just like the Continuous LookAt in example 7, we return the position of the entity. If no entity is found, we return a constant position for him to look at. Because we have the LookAt behavior set to continuous mode, Jibo will constantly be updating and looking for a target.
To see Jibo look at a target, launch the simulator and click the LPS tab. Click Add a Target in the LPS pane. A target will appear in Jibo's environment. You can manipulate the position of this target using the keyboard shortcuts shown in the LPS pane. You can also see the target's ID, x, y, and z position.
Just like a physical robot, Jibo is able to both see and listen to his environment in the simulator. In this example, Jibo tracks a target using the 19-lps.bt subtree until he hears hey jibo. We then use a Parallel behavior to simultaneously execute a TextToSpeechJs, which randomly selects from a few greeting phrases, and two Random behaviors. Random behaviors randomly choose one of their children to execute.
To see this in the simulator, launch the skill and add a target to the scene like we did in example 19. You can manipulate the target because you are accessing it via a subtree. To see the rest of the skill, click the Chat tab and type hey jibo into the chat box. He will say one of the phrases we've put in the TextToSpeechJs and randomly execute one of the PlayAudio and PlayAnimation children of the Random behavior. Then, since the whole sequence has a WhileCondition, the tree will restart.