base

modular_policy_base

StepIt plugin for composing control policies from modules.

Provided Interfaces

• stepit::modular_policy::Actuator: defines how to apply actions to the robot.
• stepit::modular_policy::Module: provides fields according to input fields.

Provided Factories

• stepit::Policy:

  • modular: module-based control policy.

• stepit::modular_policy::Actuator:

  Name	Description
  position	Translates actions to joint position commands.
  velocity	Translates actions to joint velocity commands.
  torque	Translates actions to joint torque commands.
  hybrid	Translates actions to a combination of joint commands.

• stepit::modular_policy::Module:

  Name	Description
  action_history	Provides history of action commands.
  action_filter	Applies low-pass filtering to action commands.
  action_reordering	Reorders action commands.
  field_ops	Applies generic field operations.
  joint_reordering	Reorders joint states.
  time_source	Provides step count and current policy time.

Mechanisms

Module

Classes derived from Module require to declare their input dependencies (requirements) and output fields (provisions) by registering named fields through a global FieldManager. FieldManager assigns a unique ID to each field and merges its declared size and scalar data type. At runtime, modules sequentially produce or process values identified by FieldId.

ModularPolicy

ModularPolicy orchestrates a set of Module instances into a policy pipeline. It:

1. Loads YAML configuration, reads user‐specified modules and adds a configured Actuator.
2. Ensures the action field has a source, then resolves dependencies by creating modules from unresolved requirements.
3. Resolves execution order from declared requirements/provisions, and reports circular or duplicate providers.
4. On reset(), calls reset() on each resolved module.
5. In each act() step, sequentially invokes update(), takes action from the field map, and sends it to the robot through the Actuator.
6. After act() returns and the low-level command is handed off, runs a post-act phase for module state latching and slower work such as publishing configured fields.