Lei feng’s network (search for “Lei feng’s network”, public interest): the author drones channel (ID:auscor), concerned the drones.
Is the core of UAV flight control system control unit, equivalent to the drone’s brain, fitted with flight control system model is no different from that of common air, an important symbol.
After early r/c flying in, and its navigation and intelligent flight control modes have been developed for autonomous flight. Navigation changes on accuracy of the flight control computers put forward higher requirements; with the increasing complexity of UAV mission, flight control computer requirements are also higher operational speed and miniaturization requires flight control computer power and volume are also put forward higher requirements. High precision not only requires a computer with a high control precision, but also capable of running complex control algorithms, miniaturization requires UAV’s small size, good mobility, and control the size of the smaller the better.
Many processor chips, the most suitable for small flight control computer CPU chips are the TI company TMS320LF2407, their speed and numerous peripheral interface is great for complete real-time control functions of the UAV.
It used Harvard structure, and multilevel line operation, on data and instruction while for read, tablets within since with resources including 16 road 10 bit A/D conversion device and with automatically sort function, guarantee up 16 road has conversion in same conversion during for, and not increased CPU of overhead; 40 road can separate programming or complex with of General entered/output channel; 5 a external interrupted; integrated of serial communications interface (SCI), can makes its has and system within other controller for asynchronous (RS 485) communications of capacity ; 16-bit synchronous serial peripheral interface (SPI) can easily be used to communicate with other peripherals; also offers watchdog timer module (WDT) and CAN communication modules.
Flight control system modules OtterBox iPad Mini Case
Fly control system real-time collection the sensor measurement of flight State data, and received radio control Terminal transmission of by ground control station uplink channel sent to of control command and the data, by calculation processing, output control instruction to implementation institutions, achieved on no machine in the various flight die state of control and on task equipment of management and control; while will no machine of State data and the engine, and airborne power system, and task equipment of work state parameter real-time transfer to airborne radio data terminal, Radio downlink is sent back to the ground control station.
Divided according to function, the flight control system hardware including: main control module, signal processing and interface modules, data acquisition module and servo-driven module.
All function module combination in with, constitute flight control system of core, and main control module is fly control system core, it and signal conditioning module, and interface module and rudder machine drive module phase combination, in only need modified software and simple changes peripheral circuit of based Shang can meet series small no machine of flight control and flight management function requirements, to achieved once development, more model using, reduced system development cost of purpose. System complete the following functions:
(1) complete the high-precision acquisition of analog signals, including fog, heading signal signal, rudder angle, engine speed, cylinder temperature, hydrostatic sensor signals, power supply voltage, and so on.
Due to the CPU comes with a/d converter precision and number of channels is limited, so use an alternate data acquisition circuit, chip select and control signal is generated by EPLD decoding circuit.
(2) output digital signals, analog signal and PWM signal can adapt to different implementing agencies (such as the rudder, aileron servos, airway and lifting rudder, throttle servos, etc) control requirements.
(3) the use of multiple communication channels, respectively and airborne data terminals, GPS signal communication devices, digital sensors and related tasks. Due to the SCI CPU serial channel configuration does not meet the system requirements, use a serial port expansion chip design 28C94 to extend the 8 serial ports.
System software design OtterBox iPad Mini Case
The software design is divided into 2 parts, namely logic circuit chip EPLD decoding program design and application design of flight control system.
Logic circuit design
EPLD used to form digital logic circuits, complete decoding and isolation, as well as to provide A/D,D/A,28C94 chip select signals and read/write function of the control signal.
The software design using schematic hybrid design and VERILOG HDL language programming, follow the design input design → implementation → verification → device programming processes. System uses two ispLSI1048 chips which are used to achieve the A/D,D/A control and control of serial port expansion chip 28C94, parameters derived from wing net interest drones.
System application design
Application, system, programs written in c language can not only, but also directly controls on computer hardware as an assembly language, programs written in highly portable. Because the DSP core design involved a large number of foreign based port operations, as well as considering subsequent transplantation work, so applications choose BC 3.1lai flight control system design, realization of flying control and flight management functions, respectively.
Software by function is divided into 4 modules: time management, data acquisition and processing module, communication module, a module to calculate the control law.
Through time management module in milliseconds level time within on no machine for real-time control; data acquisition module collection no machine of flight State, and attitude parameter and flight parameter, and flight State and the flight parameter for telemetry coding and through serial interface transfer to airborne data terminal, through wireless data channel sent to ground control station for flight monitoring; attitude parameter through software internal interface sent control law solutions is module for solutions is, and will results through D/A channel sent airborne servo system, control rudder machine run, reached adjustment, and The purpose of aircraft attitude; communication module to complete the flight control computers and other data exchange between onboard peripherals function.
Using high-speed DSP control chip in control law calculation and data processing aspects of advantage and rich of external resources, tie mass can programming logic devices CPLD and serial interface extended chip 28C94 design small airborne fly control computer, to its for core design of small no machine fly control system has function full, volume small, weight light, power low of features, is good to meet has small no machine on fly control computer high precision, and miniaturization, and low cost of requirements. The design has been successfully applied to a verify that the unmanned aircraft systems.