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The Clearpath Jackal as GRID drives it — what this robot actually implements, with the signatures it actually accepts. make_robot("<name>") returns a RemoteRobot. Its attributes are the methods and subcomponents below, and every call runs on the robot; the driver behind it is Jackal. Connecting neither starts nor moves the robot — it attaches to one that is already up. A method that fails on the robot arrives as RuntimeError naming the original error in its message. The client packages this page uses are preinstalled in every GRID session workspace and in the Python environment the GRID CLI prepares when you run a program with skill run; there is nothing to install.

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Methods on the robot

Called as robot.<method>(...).

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getBatteryState()

Signature
Return the latest battery-management-system reading. Returns: A dict with voltage (volts), current (amps, negative when discharging), charge_percent (0–100, or None if the BMS does not report it) — or None if no battery message has arrived yet.

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getIMU()

Signature
Return the latest IMU reading. Same keys, units and semantics as Vision60.getIMU. Returns: A dict with orientation (quaternion), angular_velocity (rad/s) and linear_acceleration (m/s²) — or None if no IMU message has arrived yet. Raises: RuntimeError: If IMU data is arriving but does not decode as sensor_msgs/Imu.

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getImage()

Signature
Return the image of camera. Which camera a no-argument call reads is decided by cardinality alone — no robot, config, or class declares a default. A robot with exactly one camera needs no name; a robot with several requires one, so adding a second camera never silently changes which one a bare getImage() returns.
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str
default:"''"
Name of the camera to get image from — either a directly attached camera’s name or a /-separated path through subcomponents to a nested one (left_arm/wrist). May be omitted when the robot has exactly one camera.
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Forwarded to the underlying sensor’s getImage. Lets callers pass camera-specific options (e.g. image_type="depth", compressed=False) without the base class having to enumerate them.
Returns: Image: The captured image. Raises: RuntimeError: If no cameras are configured, or the name is omitted on a robot with more than one camera; the message lists every configured camera path. KeyError: If camera_name is given but names no camera on this robot.

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getLidarPointCloud()

Signature
Get a point cloud from the named LiDAR sensor.
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str
default:"''"
Name of the lidar. If empty, uses the first available lidar.
Returns: Optional[PointCloud]: The point cloud, or None if lidar not found

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getMagneticField()

Signature
Return the latest magnetometer reading in tesla. Returns: Field vector in tesla as a Velocity triple (the shared three-component type; these are not velocities), or None if no magnetometer message has arrived yet.

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getOrientation()

Signature
Return the base orientation as a quaternion, from fused odometry. Yaw is dead-reckoned and drifts; roll and pitch are gravity-referenced via the IMU and do not. Returns: Orientation quaternion, or None if no odometry has arrived yet. Raises: RuntimeError: If odometry is arriving but does not decode as nav_msgs/Odometry.

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getPosition()

Signature
Return the base position in metres, from fused odometry. Dead-reckoned from wheel encoders and IMU by the platform’s EKF, in the odometry frame the stack started in. It drifts without bound and is not an absolute world position. Returns: Position in metres, or None if no odometry has arrived yet. Raises: RuntimeError: If odometry is arriving but does not decode as nav_msgs/Odometry — None means “nothing yet” only.

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getState()

Signature
Get a live state snapshot of this component’s tree. Recursive walk owned by the base class, following the lifecycle template: each class contributes only the protected local hook _local_state, and the walk composes the per-component results into one nested mapping. Subclasses must not replace this method — per-component state belongs in _local_state. With no keys, returns this component’s local state merged with one nested node per subcomponent name — the tree structure is the nesting itself, and the names mirror subcomponents (and therefore serialize() and edge introspection): a two-arm rig returns &#123;"left_arm": &#123;"joint_positions": ...&#125;, "right_arm": &#123;...&#125;&#125;, and a leaf component returns its local state alone. A component whose state could not be read (dead telemetry, not yet started, already shut down) carries an "error" entry — &#123;"error": "&lt;ExceptionType>: &lt;message>"&#125;, with its children still nested alongside — instead of its state keys. Errors are contained per node: one failing component never loses the rest of the snapshot, and the walk still descends into the failing component’s children. "error" is reserved for that purpose, and local state keys must not collide with subcomponent names; a hook violating either is reported as that node’s error. With keys, returns a flat mapping with one entry per match. Each key is a /-separated path through the component tree: every segment names a subcomponent, and the final segment may instead name an entry in that component’s local state. Because structure is the nesting, a literal path is the same as plain indexing — getState(["left_arm/joint_positions"]) returns the value of getState()["left_arm"]["joint_positions"] — and a path ending on a subcomponent yields that component’s full nested node. Segments may use shell-style wildcards over subcomponent names — * matches within one chunk and ** matches any chain of chunks — so "*_arm/joint_positions" fans out to one entry per arm, keyed by the concrete matched path. Wildcards never match state entries; only a literal final segment does. A key that matches nothing raises, so a typo is loud rather than silently absent. A matched component whose state read failed yields &#123;"error": "..."&#125; at its path. Keyed reads are lazy: a hook runs only where a key lands — a literal path executes the final component’s hook alone (not the nodes traversed on the way), a glob executes only the matched nodes, and each component’s hook runs at most once per call however many keys reach it. Components with a selective-read hook (_local_state_entries — every Robot with registered state getters) go further and execute only the getters a key names, so a ** glob probes their registries without touching hardware. The caller pays only for the state actually requested; ** and the no-keys form visit the whole tree because that is the request. State is cheap by convention: local state carries kinematics, status, and health — never bulk sensor payloads (camera frames, point clouds, scans), which stay in their dedicated methods (getImage, getPointCloud, …). Callable on a stopped tree — reading state after a soft e-stop is when it matters most — and on a partially started one, where unstarted components report a per-node error instead of failing the call.
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State paths to read, or None for the full nested snapshot. A single string is shorthand for a one-element list.
Returns: The nested state snapshot when keys is None, otherwise a flat mapping of matched path to state value or nested node. Raises: TypeError: If keys is neither None, a string, nor a list/tuple of strings. ValueError: If a key is empty, has an empty path segment, or matches no subcomponent path or state entry.

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getVelocity()

Signature
Return the measured body-frame linear velocity in m/s. Measured, not commanded — use it to close the loop on moveByVelocity. Angular velocity is available from getIMU() or getState(). Returns: Body-frame linear velocity in m/s, or None if no odometry has arrived yet. Raises: RuntimeError: If odometry is arriving but does not decode as nav_msgs/Odometry.

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isEmergencyStopped()

Signature
Report whether the platform emergency stop is currently engaged. Raises rather than returning None when the state is unknown: a caller writing if robot.isEmergencyStopped() would read an unknown state as “clear to move”, which is exactly backwards for a safety interlock. Returns: True when the stop is engaged and motion is inhibited, False when it is clear. Raises: RuntimeError: If the emergency-stop state is unknown — either nothing has arrived on the topic, or what arrives does not decode as std_msgs/Bool. The second case warns once on first read, not at bring-up.

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moveByVelocity()

Signature
Command a body-frame twist. Non-blocking: returns immediately, and the command is republished at _CMD_RATE_HZ Hz until superseded by another call, until stop(), or until duration seconds elapse — the platform MCU halts the wheels when commands stop arriving, so continuous republish is what holds a velocity. The Jackal is a differential-drive base: it cannot translate sideways. linear_velocity.y and .z are ignored, as are angular_velocity.x and .y.
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required
Body-frame linear velocity in m/s; only x (forward-positive) is actuated.
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required
Body-frame angular velocity in rad/s; only z (counter-clockwise-positive yaw) is actuated.
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default:"'body'"
Reference frame. Only "body" is supported.
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default:"1.0"
Seconds to hold the command. None republishes indefinitely until stop() or the next command.
Raises: NotImplementedError: If frame == "world". The platform accepts only body-frame twists; compose a world-frame move from getOrientation() and repeated body-frame commands. ValueError: If frame is neither "body" nor "world", if duration is negative, or if a commanded speed exceeds max_linear_speed / max_angular_speed.

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stop()

Signature
Halt all motion across this component’s tree (soft e-stop). Recursive walk owned by the base class: every subcomponent is stopped first (children before their parent, leaf-to-root; siblings in subcomponents insertion order), then this component’s own _stop_self hook runs. The walk is best-effort — a failing component never prevents the rest of the tree from being stopped; failures are collected and raised together after the walk completes. Components (and their subtrees) that have already been shut down are skipped. Safe to call repeatedly: stopping an already-stopped tree re-runs the hooks, which must tolerate that. Blocks until every hook has returned. Stops motion only; resources stay live and the component remains usable — telemetry and every other public method keep working on a stopped tree. Use shutdown to release resources. Stopping re-arms each visited component, so a later start re-runs the bring-up hooks — that is the stop-then-start restart path — but it does not revoke callability: only shutdown does that. Subclasses must not replace this method — per-component stop behavior belongs in _stop_self. An override may only extend the walk (adding a driver-specific mode, as UR5e does with its immediate escape hatch) and must delegate to super().stop() for the normal path; it must never re-implement the recursion. Raises: ComponentStopError: If one or more stop hooks raised. The walk still visited every component; the exception carries every (component_path, exception) pair.

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Properties on the robot

Read as robot.<property>; each read runs the getter on the robot.
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str
Velocity-command topic: the platform twist_mux input.
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Optional[BatteryState]
The most recent battery-management-system message, or None.
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Optional[bool]
Whether the emergency stop is engaged, or None if unknown.
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Optional[Imu]
The most recent IMU message, or None if none has arrived.
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Optional[JointState]
The most recent wheel joint-state message, or None.
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Optional[MagneticField]
The most recent magnetometer message, or None.
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Optional[Odometry]
The most recent fused-odometry message, or None if none has arrived.
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str
Fused (EKF) odometry topic.

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Lifecycle and configuration

The driver’s own bring-up and configuration hooks. The edge runs them when the robot comes up; do not call them from a program. Note that robot.shutdown() on the proxy is not the method below — it is RemoteRobot.shutdown(), which closes your connection and leaves the robot as it was.
  • addSensor() — Add an external sensor to the robot.
  • addSubcomponent() — Attach a child component under a name.
  • builtin_subcomponents() — Declare the children this class always ships with (customization point).
  • configHash() — Hash this component’s serialized config subtree.
  • config_schema()
  • from_config() — Construct this component and its config-declared subtree.
  • getIdentity() — Get this component’s own hardware identity (serial, model, version, MAC).
  • getRobotId() — Stable, readable identifier for a robot or rig, for a database key.
  • serialize() — Serialize this component tree back to its config envelope.
  • setup_shutdown_handlers() — Register the process-wide atexit and signal handlers for safe teardown.
  • shutdown() — Shut down this component’s tree, halting motion and releasing resources.
  • start() — Bring this component’s tree online (connect, enable, arm).
The contract these methods implement is Robot interface; values returned are grid-types (camera reads return Image — call decode() for an ndarray). You reach the robot through make_robot.