propulsionwhile

Propulsionwhile (PW) is a conceptual control technique in propulsion engineering. It describes maintaining propulsion operation as long as a specified predicate remains true, analogous to a while loop in programming. PW emphasizes conditional persistence of thrust under real-time sensor feedback and safety constraints.

Origin and scope: The term arises in discussions of automated propulsion control for complex systems such as spacecraft, aircraft, and marine vessels, where thrust must be sustained or adjusted while certain operational conditions hold. It is not a formal standard across all propulsion literature but appears in modeling and simulation as a descriptive pattern.

Mechanism: PW relies on a closed-loop controller that evaluates a predicate at regular intervals. The predicate can be velocity or altitude targets, distance to a boundary, or propellant state. When true, thrust is commanded according to a throttle schedule or setpoint; when false, control transitions to another mode, such as coast, brake, or shutdown. This approach integrates safety limits and energy optimization within the predicate boundary.

Applications: PW is used in simulation and onboard control systems for electric propulsion, chemical propulsion in autonomous missions, and marine or unmanned aerial platforms. It provides a modular way to encapsulate repetitive thrust behavior under conditional constraints.

See also

- Control theory

- Feedback control

- Propulsion

- Throttle management

- State machine control