**2.1.4 Implementation**

Designing the avionics box and packing the box appropriately under the fuselage of the helicopter are two main tasks to implement of the RUAV system.

Fig. 1. The avionics control system

In the actual flight environment, the weight and the size of the avionics box are strict limited. Our airborne control box, which is shown in Figure 1, is a compact aluminum alloy package mounted on the landing gear. The center of gravity of the box lies on the IMU device where is not the geometry center of the system that ensure the navigation data form IMU accurate. The digital compass and the IMU are installed on the same line, which are taken as the horizontal center of the gravity of the avionics system to locate and the other components.

The original landing gear of the model helicopter is plastic, in which is no enough room to install the designed avionics system in the fuselage of the helicopter. While, we re-design a landing gear with aluminum alloy and make a larger room under the fuselage of the model helicopter for the control box. To avoid the disciplinary vibration about 20Hz caused by characteristic of the helicopter, ENIDINE aviation wire rope isolators which are mounted between the avionics box and the changed landing gear are chosen. They are comprised of stainless steel stranded cable, threaded through aluminum alloy retaining bars, crimped and mounted for effective vibration isolation. The assembled RUAV system with the necessary components is shown in Figure 2.

Fig. 2. Implemented ServoHeli-20 RUAV

616 Advances in Wavelet Theory and Their Applications in Engineering, Physics and Technology

To our flight control system, a real-time operation system (RTOS) is required for the onboard computer system. After carefully consideration and comparison, QNX Neutrino RTOS is selected as the operation system, which is ideal for embedded real-time applications. It can be scaled to very small size and provide multitasking threads, prioritydriven pre-emptive scheduling, and fast context-switching–all essential ingredients of an embedded real-time system. The applied program can be coded and debugged in the remote windows-host computers and can be executed in the airborne computer system independently, which provides great convenience during the flight experiments without

Designing the avionics box and packing the box appropriately under the fuselage of the

In the actual flight environment, the weight and the size of the avionics box are strict limited. Our airborne control box, which is shown in Figure 1, is a compact aluminum alloy package mounted on the landing gear. The center of gravity of the box lies on the IMU device where is not the geometry center of the system that ensure the navigation data form IMU accurate. The digital compass and the IMU are installed on the same line, which are taken as the horizontal center of the gravity of the avionics system to locate and the other

The original landing gear of the model helicopter is plastic, in which is no enough room to install the designed avionics system in the fuselage of the helicopter. While, we re-design a landing gear with aluminum alloy and make a larger room under the fuselage of the model helicopter for the control box. To avoid the disciplinary vibration about 20Hz caused by characteristic of the helicopter, ENIDINE aviation wire rope isolators which are mounted between the avionics box and the changed landing gear are chosen. They are comprised of stainless steel stranded cable, threaded through aluminum alloy retaining bars, crimped and mounted for effective vibration isolation. The assembled RUAV system with the necessary

modifying the program in onboard computer.

helicopter are two main tasks to implement of the RUAV system.

**2.1.4 Implementation** 

Fig. 1. The avionics control system

components is shown in Figure 2.

components.

The full duplex wireless-LAN equipments are installed in the ground station and the airborne system to exchange data between them including receiving commands from the ground system and reporting the operating status or possible damages to the ground station. The architecture of the RUAV control system is presented in Figure 3.

Fig. 3. Architecture of the RUAV control system
