viam.components.motor.motor

Module Contents

Classes

Motor

Motor represents a physical motor.
class viam.components.motor.motor.Motor(name: str)[source]

Bases: viam.components.component_base.ComponentBase

Motor represents a physical motor.

This acts as an abstract base class for any drivers representing specific motor implementations. This cannot be used on its own. If the __init__() function is overridden, it must call the super().__init__() function.

from viam.components.motor import Motor
class Properties[source]
position_reporting: bool
SUBTYPE: Final
abstract async set_power(power: float, *, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs)[source]

Sets the “percentage” of power the motor should employ between -1 and 1. When power is negative, the rotation will be in the backward direction.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Set the power to 40% forwards.
await my_motor.set_power(power=0.4)
Parameters:

power (float) – Power between -1 and 1 (negative implies backwards).

abstract async go_for(rpm: float, revolutions: float, *, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs)[source]

Spin the motor the specified number of revolutions at specified rpm. When rpm or revolutions is a negative value, the rotation will be in the backward direction. Note: if both rpm and revolutions are negative, the motor will spin in the forward direction.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Turn the motor 7.2 revolutions at 60 RPM.
await my_motor.go_for(rpm=60, revolutions=7.2)
Parameters:

  • rpm (float) – Speed at which the motor should move in rotations per minute (negative implies backwards).

  • revolutions (float) – Number of revolutions the motor should run for (negative implies backwards).

abstract async go_to(rpm: float, position_revolutions: float, *, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs)[source]

Spin the motor to the specified position (provided in revolutions from home/zero), at the specified speed, in revolutions per minute. Regardless of the directionality of the rpm this function will move the motor towards the specified position.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Turn the motor to 8.3 revolutions from home at 75 RPM.
await my_motor.go_to(rpm=75, revolutions=8.3)
Parameters:

  • rpm (float) – Speed at which the motor should rotate (absolute value).

  • position_revolutions (float) – Target position relative to home/zero, in revolutions.

abstract async reset_zero_position(offset: float, *, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs)[source]

Set the current position (modified by offset) to be the new zero (home) position.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Set the current position as the new home position with no offset.
await my_motor.reset_zero_position(offset=0.0)
Parameters:

offset (float) – The offset from the current position to new home/zero position.

abstract async get_position(*, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs) → float[source]

Report the position of the motor based on its encoder. The value returned is the number of revolutions relative to its zero position. This method will raise an exception if position reporting is not supported by the motor.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Get the current position of the motor.
position = await my_motor.get_position()
Returns:

Number of revolutions the motor is away from zero/home.

Return type:

float

abstract async get_properties(*, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs) → Properties[source]

Report a dictionary mapping optional properties to whether it is supported by this motor.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Report a dictionary mapping optional properties to whether it is supported by
# this motor.
properties = await my_motor.get_properties()

# Print out the properties.
print(f'Properties: {properties}')
Returns:

Map of feature names to supported status.

Return type:

Properties

abstract async stop(*, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs)[source]

Stop the motor immediately, without any gradual step down.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Stop the motor.
await my_motor.stop()
abstract async is_powered(*, extra: Dict[str, Any] | None = None, timeout: float | None = None, **kwargs) → Tuple[bool, float][source]

Returns whether or not the motor is currently running.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Check whether the motor is currently running.
powered = await my_motor.is_powered()

print('Powered: ', powered)
Returns:

A tuple containing two values; the first [0] value indicates whether the motor is currently powered, and

the second [1] value indicates the current power percentage of the motor.

Return type:

Tuple[bool, float]

abstract async is_moving() → bool[source]

Get if the motor is currently moving.

my_motor = Motor.from_robot(robot=robot, name="my_motor")

# Check whether the motor is currently moving.
moving = await my_motor.is_moving()
print('Moving: ', moving)
Returns:

Whether the motor is moving.

Return type:

bool

classmethod from_robot(robot: viam.robot.client.RobotClient, name: str) → typing_extensions.Self

Get the component named name from the provided robot.

Parameters:

  • robot (RobotClient) – The robot

  • name (str) – The name of the component

Returns:

The component, if it exists on the robot

Return type:

Self

abstract async do_command(command: Mapping[str, ValueTypes], *, timeout: float | None = None, **kwargs) → Mapping[str, ValueTypes]

Send/Receive arbitrary commands to the Resource

command = {"cmd": "test", "data1": 500}
result = component.do(command)
Parameters:

command (Mapping[str, ValueTypes]) – The command to execute

Raises:

NotImplementedError – Raised if the Resource does not support arbitrary commands

Returns:

Result of the executed command

Return type:

Mapping[str, ValueTypes]

async get_geometries(*, extra: Dict[str, Any] | None = None, timeout: float | None = None) → List[viam.proto.common.Geometry]

Get all geometries associated with the Component, in their current configuration, in the frame of the Component.

geometries = await component.get_geometries()

if geometries:
    # Get the center of the first geometry
    print(f"Pose of the first geometry's centerpoint: {geometries[0].center}")
Returns:

The geometries associated with the Component.

Return type:

List[Geometry]

classmethod get_resource_name(name: str) → viam.proto.common.ResourceName

Get the ResourceName for this Resource with the given name

# Can be used with any resource, using an arm as an example
my_arm_name = my_arm.get_resource_name("my_arm")
Parameters:

name (str) – The name of the Resource

Returns:

The ResourceName of this Resource

Return type:

ResourceName

get_operation(kwargs: Mapping[str, Any]) → viam.operations.Operation

Get the Operation associated with the currently running function.

When writing custom resources, you should get the Operation by calling this function and check to see if it’s cancelled. If the Operation is cancelled, then you can perform any necessary (terminating long running tasks, cleaning up connections, etc. ).

Parameters:

kwargs (Mapping[str, Any]) – The kwargs object containing the operation

Returns:

The operation associated with this function

Return type:

viam.operations.Operation

async close()

Safely shut down the resource and prevent further use.

Close must be idempotent. Later configuration may allow a resource to be “open” again. If a resource does not want or need a close function, it is assumed that the resource does not need to return errors when future non-Close methods are called.

await component.close()