Module controlled-components

This module houses components that utilize sensor feedback to transform sensor readings and/or control actuators.

Model viam:controlled-components:sensor-controlled

The sensor-controlled model is a base that combines movement sensors with PID controls to actuate a base component.

Configuration

The following attribute template can be used to configure this model:

{
"base": <string>,"movement_sensor": [<string>, <string>],
"control_frequency_hz": <float>,"control_parameters": [
{
"type": "linear_velocity",
"p": <float>,"i": <float>,"d": <float>,
},
{
"type": "angular_velocity",
"p": <float>,"i": <float>,"d": <float>
},
]
}

The combination of movement sensors must provide the AngularVelocity and LinearVelocity endpoints. Providing the Position, Orientation, and CompassHeading endpoints will also improve the behavior of the base, but are not required.

Attributes

The following attributes are available for this model:

Name	Type	Inclusion	Description
base	string	Required	The name of the base that we want to apply PID controls to
movement_sensor	[]string	Required	the movement sensors that will be used for controls. The combination of movement sensors must provide the AngularVelocity and LinearVelocity endpoints. Providing the Position, Orientation, and CompassHeading endpoints will also improve the behavior of the base, but are not required.
control_frequency_hz	float64	Optional	the frequency that the PID controller will run at. Ensure this frequency is less than or equal to the movement sensor's supported frequency. Default is 10 Hz
control_parameters	[]object	Required	an array of objects that provide the gains of the PID controller. Two must be configured.

The control parameter object has the following parameters. Setting the PID gains to all be 0 will put the base in PID tuning mode.

Name	Type	Inclusion	Description
type	string	Required	specifys what the PID values are controlling. Must be linear_velocity or angular_velocity
p	float	Required	the proportional gain for PID controls
i	float	Required	the proportional gain for PID controls
d	float	Required	the proportional gain for PID controls

Example Configuration - Automatically tune the base

To configure your base to automatically tune, use the following configuration:

{
"base": "my-wheeled-base",
"movement_sensor": ["my-wheeled-odometry"],
"control_parameters": [
{
"type": "linear_velocity",
"p": 0,
"i": 0,
"d": 0,
},
{
"type": "angular_velocity",
"p": 0,
"i": 0,
"d": 0
},
]
}

WARNING: Please have your base in a safe location, as it will begin moving once the machine finishes configuring.

After tuning is completed, update the PID values in your config. The PID values can be found in the machine's logs or via the DoCommand.

Example Configuration - Using tuned parameters

If you already have tuned PID values, the configuration should look like:

{
"base": "my-wheeled-base",
"movement_sensor": ["my-wheeled-odometry"],
"control_parameters": [
{
"type": "linear_velocity",
"p": 236.8709,
"i": 708.7561,
"d": 0
},
{
"type": "angular_velocity",
"p": 0.76573,
"i": 2.30213,
"d": 0
}
]
}

DoCommand

Get the Tuned PID gains of the base

This command will retrieve the tuned PID gains of the base when tuning has completed.

{
"get_tuned_pid": ""
}