# `BB.ExampleRobots.PlanarRover`
[🔗](https://github.com/beam-bots/bb/blob/main/test/support/example_robots.ex#L1063)

A rover whose base moves in the ground plane, plus a revolute mast.

The `:base` joint is `:planar` with a vertical surface normal, so the chassis
has three degrees of freedom — two in-plane translations and yaw. The mast
above it is an ordinary revolute joint, which makes this a chain where a
multi-DoF joint and a single-DoF joint compose.

# `child_spec`

```elixir
@spec child_spec(Keyword.t()) :: Supervisor.child_spec()
```

Returns a child specification for starting this robot under a supervisor.

# `robot`

```elixir
@spec robot() :: BB.Robot.t()
```

Returns the optimised robot representation.

This struct is built at compile-time from the DSL definition and contains:
- All physical values converted to SI base units (floats)
- Flat maps for O(1) lookup of links, joints, sensors, and actuators
- Pre-computed topology metadata for efficient traversal

## Examples

    robot = Elixir.BB.ExampleRobots.PlanarRover.robot()
    {:ok, link} = BB.Robot.get_link(robot, :base_link)
    {:ok, joint} = BB.Robot.get_joint(robot, :shoulder)

# `start_link`

```elixir
@spec start_link(Keyword.t()) :: Supervisor.on_start()
```

Starts the robot's supervision tree.

## Options

All options are passed through to sensor and actuator child processes.

---

*Consult [api-reference.md](api-reference.md) for complete listing*