By : Dipl.-Ing. Endri Rachman
Introduction & Objective
Autonomous motions of an unmanned system, like the guided missile, the aircraft equipped with autopilot, the UAV, the underwater, are controlled and navigated by an embedded controller hosting the autonomous algorithms/ flight control laws. During the development process, the embedded controller must be tested in laboratory environment using so called Hardware In-The-Loop Simulator (HILS) before entering the testing in the real flight, see figure 1.
Figure 1 : Step by Step procedure in designing and developing the autonomous algorithms for UAV's Autopilot.
The HILS allows the testing of the autonomous control laws regarding their mission functionality, their operational scenario, and their robustness against changing parameter. Although HILS can’t replace the testing of embedded controller in the real flight condition, it measurably reduces the likelihood of controller’s failure by detecting bugs and deficiencies of the control laws in the laboratory. Hence, the risk of unmanned system’s failure and its associated danger the people, property, and the infrastructure during the flight can be avoided .
To facilitate such difficult and complex functions, a low cost and unique HILS for Unmanned System has been designed and developed, see figure 2. This HILS is versatile so that it can be applied on any unmanned system.
Figure 2 : Set-up of HILS for Unmanned System
In order to achieve the above objective, HILS for Unmanned System has following capabilities, see figure 3 :
- Doing rapid prototyping of the controller (running the flight controller in real time )
- Producing the real-time flight of aircraft in quasi real 3D-flight environment,
- Displaying the flight information as real as possible in cockpit- format
- Mapping the aircraft position
- Managing different useful signals/ information seamlessly
Figure 3: Monitor displays of HILS
This HILS has used a latest ICT technology, namely Grid Computing Technology. Instead of using one very expensive Super Computer to implement the capabilities mentioned above, this HILS uses four low cost computers connected to each other using Internet/ Local Area Network and serial communication RS232. Each computer has own unique IP address and plays different roles, see Figure 4:
- 1st Computer is a real time target controller/ embedded controller PC 104/+ . It serves as a real-time flight controller hosting the autonomous control laws.
- 2nd Computer is a real-time target simulator producing the flight motion/sensor data during the flight.
- 3rd Computer is a Host Simulator used for visualizing the flight of the aircraft in 3D – real flight environment, for displaying the flight information on the standard six cockpit’s display panels, for controlling the flight operation of the aircraft and for down-loading the model of the aircraft dynamics model into the real time flight simulator.
- 4th Computer is a Host controller. It is used for down loading the autonomous flight control law into the target controller/ embedded controller PC 104/+ and for mapping the aircraft position using the Google-earth.
Figure 4: System architecture of HILS for Unmanned System
There are three types of communication protocols used to exchange data/information between the computers:
- the internet protocols TCP/IP are utilized for downloading the equation of motion (dynamic model) from the host simulator into the target simulator, the control laws from the host controller into the target controller/ embedded controller PC 104/+.
- the internet protocols UDP/IP are used to exchange their data between the host simulator and the target simulator .
- the Serial communication RS232 is applied for exchange sensor and actuator data between the target simulator and the target controller/ embedded controller in real-time.
Awards for HILS
- The Malaysian Association of Research Scientist has awarded the best -award and the gold medal during the 7th –Invention and Innovation Competition for the category “aerospace and aviation with the product “ Hardware In-The Loop Simulator for Unmanned System” regarding Malaysia Technology Exhibition (MTE) 2009 on February 29 – 21, at Putra World Trade Centre in Kuala Lumpur - Malaysia .
- The International jury of IENAhas awarded the bronze medal for the product during the international trade fair "Ideas-Inventions-New Products" -IENA 2009, on November 7, 2009 , Nurenberg -Germany .