ATTHeS - A HELICOPTER IN-FLIGHT SIMULATOR WITH HIGH BANDWIDTH CAPABILITY

The demands to extend the operational capabilities of helicopters are driving the need to implement advanced high authority flight control systems. These control systems will allow the designers to tailor the handling qualities with respect to the flight task. The complexity of these systems recommends an integrated design approach using both ground based and in-flight simulation. Based on a fly-by-wire / fly-by-light BO 105, the helicopter in-flight simulator ATTHeS (Advanced Technology Testing Helicopter System) was developed. The onboard computer system consists of two computers. One computer is responsible for the data collection, telemetry and data storage, the second one handles the flight control task. Program code and data transfer can be accomplished by different computer systems via a network. Before undergoing any flight tests, a realtime hardware/software-in-the-loop simulation with a nonlinear helicopter simulation program has to be successfully performed. An explicit model following control system with a dynamic feedforward, based on the identified parameters of an extended mathematical model of the host helicopter, and an optimized feedback control system, is developed. In a first utilization, Right tests with ATTHeS were performed to generate handling qualities data with decoupled rate command/attitude hold and attitude command models. The analysis of the flight tests demonstrate the high fidelity and flexibility of the control system. Especially the decoupling performance and the flexibility of the system to simulate the various configurations with a bandwidth between 1 and 5 rad/s in the roll axis is underlined with the flight test results.