Flight Control and Systems Integration

Rotor head of an ARTIS helicopter as the main control element Simplified scheme of the control loop Helicopter tail with sensors, laser reflector, and data links Specified and flown path using the adaptive control system

For unmanned aircraft, the requirements of the flight control and decision system are primarily defined through the payload, which is contrary to the systems within manned aviation. Beside the automatic trajectory following, an efficient use of the physical capabilities is a significant demand to the control system.

Due to the lack of a pilot, a permanent and automatic supervision of the system status is required. Within some limits, the system should be able to handle irregularities automatically. For example, a reactive evasion after the detection of dangerous obstacles becomes possible. Based on the gathered information, it is required to generate a path that avoids the obstacle and to integrate this path into the desired trajectory.

In contrast to manned aviation, extensive system identification makes often no sense from the economic perspective. The large number of possible basic systems in combination with the exchangeable avionic modules allows the adaptation to a variety of application requests. For example, the change of the helicopter platform would require a new and extensive system identification that is beyond any proportion to the cost of the basic system. Hence, an adaptive and learning control concept is favored for the developments. After the identification of a simple basic model, further adaptations to the specific properties of each single aircraft should be done more or less automatic.

The development of an adaptive flight control system

• with a compromise between extensive (and expensive) system identification and the usage of (critical) adaptive elements,
• which is able to use the full performance capabilities (flight envelope) of the aircraft,
• to produce a system that can compensate errors automatically,

includes activities like

• system identification,
• integration of MATLAB Real Time Workshop Code,
• test of robust control techniques,
• selection and integration of adaptive and learning elements.

Beside the research activities within flight control and guidance of unmanned helicopters and fixed-wing aircraft, the group is also doing the work dealing with the integration of all single hardware and software components into a hardware-in-the-loop simulation environment and into the overall system that is capable of flying. Further, the activities include the operation of the aircraft including maintenance and development of the flight test demonstrators, the organization of flight tests and the provision of the operational safety during the flight tests.