BB.Actuator.Server (bb v0.23.0)

Wrapper GenServer for actuator callback modules.

This module manages the lifecycle of user-defined actuator modules, handling:

Parameter reference resolution at startup
Subscription to parameter changes
Subscription to the actuator's own command topic
Delegation of GenServer callbacks to user module
Automatic safety registration

User modules implement the BB.Actuator behaviour and define callbacks. This server wraps them, providing the actual GenServer implementation.

The inbound command pipeline

Commands reach an actuator by three transports - published to [:actuator | path], cast via BB.Process.cast/3, or called via BB.Process.call/4. All three converge here and pass through the same checks before the driver sees them:

The robot must be armed. BB.Message.Actuator.Command.Stop is exempt, since stopping is the fail-safe direction and a supervisor must be able to stop a joint it didn't arm.
The payload is translated from joint-space into motor-space using the joint's transmission.

The driver then receives it in BB.Actuator.handle_command/2, and its reply is routed back to whichever transport delivered the command. Messages from topics the driver subscribed to itself are not part of this pipeline - they reach BB.Actuator.handle_info/2 untouched.

Summary

Types

t()

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

Types

t()

@type t() :: %BB.Actuator.Server{
  actuator_name: atom() | nil,
  bb: %{robot: module(), path: [atom()]},
  callback_module: module(),
  command_topic: [atom()],
  joint: map() | nil,
  joint_name: atom() | nil,
  param_subscriptions: %{required([atom()]) => atom()},
  raw_opts: keyword(),
  resolved_opts: keyword(),
  transmission: BB.Transmission.t() | nil,
  transmission_subscriptions: %{required(atom()) => [atom()]},
  user_state: term()
}

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.