Incremental Nonlinear Dynamic Inversion for the Apache AH-64 Helicopter Control

摘要

INDI is a promising technique for controlling highly nonlinear dynamic systems. An INDI controller was developed and tested in a simulator environment for the Apache AH-64D helicopter to provide improved HQs for hover/low-speed flight in DVEs. The INDI controller was implemented into the Boeing FLYRT flight mechanics model running in the SRS at Delft University. The FLYRT model is the Boeing high-fidelity Apache flight dynamics model enhanced with AFCS. The INDI control scheme proposed in this paper requires using measurements of angular accelerations by sensor-based rotational accelerometers mounted on the vehicle structure instead of use of a complete on-board aerodynamic model. Among the advantages of sensor-based INDI technique one can mention (1) the control structure is simple; (2) reallocation of control power and the reconfiguration of control laws can be achieved conveniently and rapidly; (3) it is a semimodel free approach; (4) no model identification is needed; (5) the controller is inherently robust. However, the sensor-based INDI technique also faces major challenges: (1) the measurement of angular acceleration is often noisy and requires filtering. This filtering introduces a delay in the measurement, which needs to be compensated. (2) The method relies on inversion and therefore needs a control effectiveness model.