Unmanned aircraft connected via a Vector interface to CANoe and Virtual Flight Test Environment
How can you reduce system and human failures in unmanned aviation? How can UAS be tested with conventional drone hardware and software? And how can real flight tests in the training of UAS pilots be reduced?
Find out more in the following case study that was created together with AlphaLink Engineering!
AlphaLink Engineering GmbH is a spin-off from Technische Universität Berlin. AlphaLink is specialized in the development and implementation of mechatronic systems. The focus is on the system design of mechatronic systems in aviation, which includes the modeling and control of the entire aircraft, but also of its individual components. With the "Flying Lab" and the "Virtual Flight Test Environment", AlphaLink offers two products in the field of Flight Control for Unmanned Aircraft Systems (UAS).
Hardware-in-the-loop simulators (HIL) have been used in manned aviation for a long time to reduce the risk of system failures and pilot errors. A HIL enables testing of the entire system with actuators and displays and training of pilots on aircraft with new flight control systems and/or displays. A variety of solutions for HIL exists for UAS, but a high level of safety is required in aviation. The goal was to establish a toolchain for the most widely used flight control computer, the Pixhawk, to test the system safely with commercial software and hardware that is already used in manned aviation. For this purpose, the Pixhawk ought to be connected to CANoe via a CAN interface.
Building a Digital Twin and Linking the Digital World With the Real World via a Can Interface
Two main components are needed to build a high-quality HIL:
a digital twin of the UAS with all its components such as flight dynamics, sensor models, and actuator models, and
a bridge between the digital world and the real existing flight control system (FCS) with all its components, such as data link and remote control.
The digital twin was replicated in a Simulink model. In system identifications, the real behavior of flight dynamics, sensors and actuators were determined and formulated into mathematical models in Simulink. The Simulink model was linked to CANoe. The Pixhawk has a CAN interface that can be configured for different operating modes. However, a direct connection to CANoe was not possible. Therefore, the Flight-Stack was modified. In addition, software modules that normally read out the sensors were adapted so that the measurement data like IMU and GPS were replaced by the corresponding CAN messages from CANoe. Commands from the FCS to the actuators are transmitted via CAN messages back to CANoe and thus also to the Simulink model. This allows to simulate a flight with all components. In addition, specific error cases can be implemented. To visualize the flight movement, the Virtual Flight Test Environment is used, which provides a three-dimensional view of the UAS flight in a real environment presented in the web browser.
Implementation of the Hardware-in-the-Loop Simulator (Photo: AlphaLink Engineering GmbH)
Reduction of System and Human Failures in Unmanned Aviation
Increase safety for UAS and payload by reducing risks of system failures and human error in real-world operation
Testing with valid state-of-the-art test software and hardware to ensure a high-quality standard of safety
Applicability of the entire concept to any UAS that has a Pixhawk flight control computer
Testing of UAS with conventional drone hardware and software
Training of UAS pilots on aircraft with new flight control systems and/or displays to reduce costs for real flight tests