BB.Ufactory.Actuator.Joint (bb_ufactory v0.1.0)

Joint-space position actuator for xArm joints.

One instance runs per joint. On receiving a %BB.Message.Actuator.Command.Position{} command, the actuator clamps the angle to joint limits and writes the target set_position into the controller's ETS table. The controller's 100 Hz loop reads all pending set_position values and batches them into a single cmd_move_joints frame.

Commands are accepted via two delivery paths:

• Pubsub (BB.Actuator.set_position/4): arrives as handle_info({:bb, [:actuator | path], msg}, state).
• Direct cast (BB.Actuator.set_position!/4): arrives as handle_cast({:command, msg}, state).

Both paths share the same clamping and ETS write logic.

ETS Write

The actuator reads the current ETS row first to preserve current_position and current_torque written by the controller's report socket handler, then writes only the set_position field.

BeginMotion

A BB.Message.Actuator.BeginMotion message is published to [:actuator | bb.path] after each position command so that the open-loop position estimator can track expected arrival.