> For the complete documentation index, see [llms.txt](https://yams.yassrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yams.yassrobotics.com/api-reference/java-reference/mechanisms/flywheel.md).

# FlyWheel

**Package:** `yams.mechanisms.velocity`\
**Extends:** `SmartVelocityMechanism`

`FlyWheel` controls a continuously spinning wheel or roller at a target angular velocity. It is not position-controlled; hard limits do not apply.

**See also:** [FlyWheelConfig](/api-reference/java-reference/config/flywheel-config.md) | [C++ FlyWheel](/api-reference/c++-reference/mechanisms/flywheel.md)

***

## Constructor

```java
FlyWheel(FlyWheelConfig config, SmartMotorController smc)
```

| Parameter | Type                   | Description                                                           |
| --------- | ---------------------- | --------------------------------------------------------------------- |
| `config`  | `FlyWheelConfig`       | Flywheel configuration including gear ratio and simulation parameters |
| `smc`     | `SmartMotorController` | Motor controller driving the flywheel                                 |

***

## State Queries

### `getSpeed()`

```java
public AngularVelocity getSpeed()
```

Returns the current wheel velocity from the encoder.

| Name | Type | Description   |
| ---- | ---- | ------------- |
| N/A  | N/A  | No parameters |

**Returns:** `AngularVelocity`: current wheel velocity.

***

## Command Factories

### `run(AngularVelocity target)`

```java
public Command run(AngularVelocity target)
```

Spins the wheel at `target` indefinitely using closed-loop velocity control.

| Name     | Type              | Description            |
| -------- | ----------------- | ---------------------- |
| `target` | `AngularVelocity` | Desired wheel velocity |

**Returns:** `Command`: runs until interrupted.

***

### `runTo(AngularVelocity target, AngularVelocity tolerance)`

```java
public Command runTo(AngularVelocity target, AngularVelocity tolerance)
```

Spins to `target` and ends when the wheel speed is within `tolerance` of the target.

| Name        | Type              | Description                                      |
| ----------- | ----------------- | ------------------------------------------------ |
| `target`    | `AngularVelocity` | Desired wheel velocity                           |
| `tolerance` | `AngularVelocity` | Acceptable speed error for the command to finish |

**Returns:** `Command`: ends when within tolerance.

***

### `set(double dutycycle)`

```java
public Command set(double dutycycle)
```

Runs the flywheel open-loop at the specified duty cycle indefinitely.

| Name        | Type     | Description                            |
| ----------- | -------- | -------------------------------------- |
| `dutycycle` | `double` | Motor output in the range \[-1.0, 1.0] |

**Returns:** `Command`: runs until interrupted.

***

### `set(Supplier<Double> dutycycle)`

```java
public Command set(Supplier<Double> dutycycle)
```

Runs the flywheel open-loop with a duty cycle supplier; the supplier is re-evaluated each loop iteration.

| Name        | Type               | Description                                               |
| ----------- | ------------------ | --------------------------------------------------------- |
| `dutycycle` | `Supplier<Double>` | Supplier returning motor output in the range \[-1.0, 1.0] |

**Returns:** `Command`: runs until interrupted.

***

### `setVoltage(Voltage volts)`

```java
public Command setVoltage(Voltage volts)
```

Runs the flywheel open-loop at a fixed voltage indefinitely.

| Name    | Type      | Description           |
| ------- | --------- | --------------------- |
| `volts` | `Voltage` | Applied motor voltage |

**Returns:** `Command`: runs until interrupted.

***

### `setVoltage(Supplier<Voltage> volts)`

```java
public Command setVoltage(Supplier<Voltage> volts)
```

Runs the flywheel open-loop with a voltage supplier; the supplier is re-evaluated each loop iteration.

| Name    | Type                | Description                              |
| ------- | ------------------- | ---------------------------------------- |
| `volts` | `Supplier<Voltage>` | Supplier returning applied motor voltage |

**Returns:** `Command`: runs until interrupted.

***

## Triggers

### `isNear(AngularVelocity speed, AngularVelocity tolerance)`

```java
public Trigger isNear(AngularVelocity speed, AngularVelocity tolerance)
```

True when the current wheel speed is within `tolerance` of `speed`.

| Name        | Type              | Description                  |
| ----------- | ----------------- | ---------------------------- |
| `speed`     | `AngularVelocity` | Reference speed              |
| `tolerance` | `AngularVelocity` | Maximum acceptable deviation |

**Returns:** `Trigger`

***

### `atSpeed()`

```java
public Trigger atSpeed()
```

Shorthand for `isNear` using the configured target speed and a default 50 RPM tolerance.

**Returns:** `Trigger`

{% hint style="info" %}
Use `atSpeed()` as a command prerequisite when sequencing shooter commands. The default 50 RPM tolerance works for most shooters; use `isNear` to set a tighter bound.
{% endhint %}

***

### `gte(AngularVelocity speed)`

```java
public Trigger gte(AngularVelocity speed)
```

True when the current wheel speed is greater than or equal to `speed`.

| Name    | Type              | Description       |
| ------- | ----------------- | ----------------- |
| `speed` | `AngularVelocity` | Lower bound speed |

**Returns:** `Trigger`

***

### `lte(AngularVelocity speed)`

```java
public Trigger lte(AngularVelocity speed)
```

True when the current wheel speed is less than or equal to `speed`.

| Name    | Type              | Description       |
| ------- | ----------------- | ----------------- |
| `speed` | `AngularVelocity` | Upper bound speed |

**Returns:** `Trigger`

***

### `between(AngularVelocity start, AngularVelocity end)`

```java
public Trigger between(AngularVelocity start, AngularVelocity end)
```

True when the current wheel speed is in the inclusive range `[start, end]`.

| Name    | Type              | Description              |
| ------- | ----------------- | ------------------------ |
| `start` | `AngularVelocity` | Lower bound of the range |
| `end`   | `AngularVelocity` | Upper bound of the range |

**Returns:** `Trigger`

***

### `max()`

```java
public Trigger max()
```

Not applicable to velocity mechanisms. Throws `UnsupportedOperationException`.

**Returns:** `Trigger`: always throws; do not use.

***

### `min()`

```java
public Trigger min()
```

Not applicable to velocity mechanisms. Throws `UnsupportedOperationException`.

**Returns:** `Trigger`: always throws; do not use.

***

## Visualization & Simulation

### `getMotor()`

```java
public SmartMotorController getMotor()
```

Returns the underlying motor controller.

**Returns:** `SmartMotorController`

***

### `simIterate()`

```java
public void simIterate()
```

Advances the flywheel physics simulation by one loop iteration. Call this in `simulationPeriodic()`.

***

### `updateTelemetry()`

```java
public void updateTelemetry()
```

Publishes the current flywheel state to NetworkTables.

***

### `visualizationUpdate()`

```java
public void visualizationUpdate()
```

Updates the Mechanism2d visualization for Shuffleboard or AdvantageScope.

***

## Examples

{% @github-files/github-code-block url="<https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/simple_shooter/java/frc/robot/subsystems/ShooterSubsystem.java#L150-L156>" %}

{% @github-files/github-code-block url="<https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/hooded_shooter/java/frc/robot/subsystems/FlywheelSubsystem.java#L102-L109>" %}