Design and implementation of integrated cockpit display control system

O Introduction

In modern avionics systems, the integrated cockpit display control system undertakes the centralized display and centralized management of the avionics system, enabling pilots to efficiently obtain the required information and effectively reducing the pilot's workload. At present, domestic general aircraft and helicopters are equipped with mechanical instruments, or the flight displays are small in size and low in resolution, with fewer flight parameters displayed on a single screen, relatively heavy in weight, and low system reliability.

The integrated cockpit display control system introduced in this article absorbs the concept of "glass cockpit" and presents a large amount of complex sensor data to the pilot through a large-screen high-resolution LCD display after collection, processing and fusion, replacing the traditional electromechanical instruments. At the same time, the integrated cockpit display control system uses a high-speed data network to realize data transmission, task synchronization and data comparison, which can flexibly handle various fault modes of the system, so that the system has the ability to work under a certain fault level, thereby improving the reliability and safety of the system.

1 Design Concept

1.1 Integration

Adopting a highly integrated integrated design, the integrated cockpit display and control system integrates universal modules, standard buses, high-speed networks and real-time embedded operating systems into a high-performance computing platform, providing powerful data processing, signal processing, interface processing and graphics processing capabilities, and has multiple functions such as comprehensive processing of sensor input data, data fusion, mission calculation, video information generation, navigation calculation, plug-in management, electronic countermeasures, communication management, system control and fault detection, reconstruction, etc., fully embodying the characteristics of information integration, display integration, function integration, hardware integration, software integration and detection integration.

1.2 Generalization

The cockpit display systems of different aircrafts have diverse characteristics, which is mainly due to the different uses of aircrafts, different requirements of airworthiness regulations and operating regulations. In order to improve the versatility of the integrated cockpit display system and make it suitable for various types of military and civil aircraft, the universal integrated cockpit display control system should have high-performance information integrated processing and integrated display functions, some of the most basic sensor equipment functions and strong sensor equipment interface expansion capabilities.

1.3 Miniaturization

Miniaturization design reduces the size and weight of equipment through reasonable system structure, advanced display technology and reinforcement methods. Through system optimization, it reduces the waste of redundant software and hardware resources, and at the same time uses technologies such as large-scale integrated circuits and active matrix liquid crystal displays to reduce hardware weight and volume.

2 System Design

2.1 System structure

The integrated cockpit display control system includes two large-size, high-resolution integrated displays and a multi-function control panel. It adopts a highly integrated integrated design, integrating airborne data processing, avionics task management and graphic image display inside the flight display. There is no separate display control task computer, which makes the entire display control system rationally composed, reduces the structural weight, and simplifies the helicopter cockpit layout and instrument panel layout.

As shown in Figure 1, the data from various sensors on the aircraft are first processed by the data acquisition processing unit of the integrated display and organized into network data frames, and then the data frames are transmitted to the display processing unit of the integrated display through the network. After receiving the data frames, the display processing unit performs data fusion and image processing, and finally completes the image display. The integrated cockpit display control system adopts a modular design method, which is divided into a display processing unit, a data processing unit and a multi-function control panel according to function. The functional unit is composed of universal field replaceable modules, with a high degree of standardization, which improves the maintainability of the system. The functional units are connected through a data network. This loose coupling method can not only provide flexible scalability and testability, but also improve the fault tolerance of the system.

2.2 System fault tolerance mechanism

The fault-tolerant mechanism of the integrated cockpit display control system is that multiple integrated flight displays are of the same configuration and work independently. Each integrated display integrates flight data processing, avionics task management and graphic image display functions, that is, the software and hardware configurations are the same, the operating tasks are different, they work independently and back up each other. The integrated displays realize task cycle synchronization between the two aircraft and cross-transmission of data between flight displays through display synchronization data network and cross-comparison data network. Each integrated display can obtain the aircraft information collected by another integrated display, and on this basis, realize comparative monitoring of flight parameter data. When the difference exceeds a certain range requirement, the system will give an alarm prompt. It is conducive to early detection of faults, determination of fault sources, elimination of fault spread, suppression of fault impact, and improvement of system task reliability.

According to the system comparison monitoring results and the equipment BIT monitoring results, as shown in Figure 2, if a serious fault occurs in the data acquisition and processing part of the integrated display, the main and co-pilot integrated displays can be reconstructed through the fault switching logic, and the flight display data source can be automatically switched to the data processing module of another flight display without fault. The data processing part can achieve a single fault working capability under a certain fault level. At the same time, the pilot can manually switch the data source displayed by the main and co-pilot flight displays through the multi-function control panel.

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2.3 Display interface design

In order to develop a graphical interface on an embedded operating system, the VxWorks operating system is combined with the Idata and OpenGL graphics driver development kits to achieve a good human-machine interface. The message queue, interrupt processing and task scheduling functions of the VxWorks operating system are used to realize system task management and user interaction; the GUI editor provided by the visual graphics development tool IData is used to draw the display screen, complete the situation awareness fusion display, user interactive display and advanced system display, and better realize the display functions such as flight instruments, map navigation, layered overlay of graphics, and graphic special effects, so that the message-driven multi-window display technology can achieve practical results. As shown in Figure 3, the main flight interface is divided into two areas, the upper area displays important flight parameters such as heading attitude, flight guidance, and atmospheric data; the lower area displays information such as horizontal attitude indication, route, and engine parameters.

2.4 Software Architecture

Integrated cockpit Display control The system software mainly includes three parts: system software, ground support software and application software. The software system structure is shown in Figure 4.

The application software (OFP software) runs on the VxWorks 5.1 operating system as the core part of the integrated cockpit display control software architecture. It is developed using the standard C language and is responsible for completing the integrated display and control of flight status and parameters, display key operation processing, data acquisition, network communication, periodic self-test, fault warning and processing functions, data loading, system maintenance and other functions, and realizes the control, conversion and information display of the working status and working mode defined in the pilot operation procedure. The data processing software realizes the data exchange between the integrated cockpit display control system and the carrier aircraft sensor equipment, and sends it to the display processing unit after being fused with the system status data. The display processing software receives the display instructions sent by the data processing software through the network and generates the corresponding screen according to the display instructions.

System software includes operating system, middle-layer software and device driver software. Application software and system software are installed in the program memory of the integrated display control system. Ground support software includes Tornado integrated development environment (IDE), various online simulation debugging equipment and software (ICE), burning and curing tools, project management tools (such as version management software), system comprehensive simulation test equipment software (ATE), ground route editing software and database, etc. They are installed in ground maintenance equipment or development equipment.

3 Conclusion

From the above discussion, it can be seen that the integrated cockpit display control system adopts advanced system architecture and software architecture to realize the graphical integrated display control function of cockpit information. The system has a high degree of integration, good ergonomics, high safety, strong versatility, and is compatible with multiple aircraft platforms. It conforms to the development trend of highly integrated cockpit display and control systems and has good application prospects.