System Architecture of HALAS - A Helicopter Slung Load Stabilisation and Positioning System

Abstract

To support helicopter pilots during slung load operations currently a pilot assistance system called Hubschrauber- Außenlast-Assistenzsystem (HALAS) is being developed within a cooperation of the German Aerospace Centre (DLR) and iMAR Navigation GmbH. The objective of this research is the demonstration of an automatic slung load stabilisation and positioning system during the flight test with DLR’s research helicopter Active Control Technology/ Flying Helicopter Simulator (ACT/FHS). The automatic slung load control system is being designed to extend the functionalities of the helicopter’s stability, control and augmentation system. The control system will be able to handle the challenges of rescue hoist operations. This means compensation of additional roll, pitch and yaw moments created by a significant distance of the load suspension point to the helicopter’s centre of gravity and the handling of a variable cable length. To measure the slung load motion, an optical-inertial sensor is being developed by iMAR Navigation GmbH. In this paper, the overall system architecture of HALAS as well as the hardware integration into the ACT/FHS is explained. The optical-inertial sensor used for the slung load dynamics measurement and estimation is described in detail. Furthermore, a first system analysis of a simulation model used for the later controller design is presented. The focus of the stability analysis is laid on variations of cable length, load mass and load suspension point position. The control law development process itself is not part of this paper but will be published later.