"In the complex UAV products, four-rotor aircraft for its simple structure, inexpensive and easy to use, cost and other advantages, the first to enter the public's attention. However, this requires the ability to control the aircraft in flight is the highest, it appears to stimulate the large open MEMS sensor based flight control.
How to define open source
Open source (Open Source) The concept of the first to be used in open source software, Open Source Initiative (Open Source Initiative) who used it to describe software source code can be used by the public, and using this software, modification and distribution are not subject to license restrictions.
Every open source project all have their own forum, managed by teams or individuals, forums regularly publish open source code, interested programmers can download the code and modify it, and then upload their results, management to choose the appropriate code from the numerous modifications to improve the program and release a new version again. This cycle, the formation of "common development and common share" a virtuous circle.
The gradual development of open source software combined with hardware, resulting in open source hardware. Hardware and software is different is that in-kind resources should be committed to creating physical goods. Therefore, the production of items under an open source hardware (OSHW) license (product) of the product and the company is not obliged to clear production, sales and authorization before approving the original designer, and do not use any trademark owned by the original designer. Specific format hardware design of the source code can be get others to modify it. While realizing technology free, open source hardware to provide knowledge sharing and encourage open communication hardware design trade.
Open source hardware (OSHW) the definition of 1.0 is defined in the software-defined on the basis of open source. This definition is rather created by Bruce Perens and Debian developers as the Debian Free Software Guidelines. Open source flight control is what things? Understand the concept of open source hardware, the concept of open source flight control will be more easy to understand. The so-called open-source flight control is built on the idea of open source on the basis of automatic flight control project (Open Source Auto Pilot), containing both open source software and open source hardware, and software are included flight control ground station hardware, firmware and software in two parts. Lovers can not only participate in the development of software, hardware can also participate in research and development, not only can buy hardware to develop software, hardware can be made, so you can let more people enjoy the freedom to develop the results of the project. The use of open-source projects have a commercial, so each flight control open source projects will be given an official legal provisions to define the rights of developers and users, different open source flight control its legal definition are different.
Development of open-source flight control
Development of open source flight control can be divided into three generations:
The first generation flight control system using open source Arduino electronic or other open source platform, various MEMS sensors expansion connector, allowing the UAV to fly stably, its main feature is modular and scalable.
The second-generation open source flight control systems mostly have their own open source hardware, environment and community development, the use of fully integrated hardware architecture, all 10DOF sensor, host microcontroller, and even GPS and other devices all integrated in a circuit board in order to improve reliability sex. It uses a three-axis digital MEMS AHRS sensors (IMU); able to control the aircraft to complete autonomous flight routes, while the installation of radio communication with ground stations, initially with complete autopilot function. Such flight control can also support a variety of unmanned devices include fixed-wing aircraft, multi-rotor aircraft, helicopters and vehicles, and have a variety of flight modes, includes flight manual, semi-autonomous and fully autonomous flight flight. The main features of the second generation flight control is a high integration, high reliability, its function has been close to commercial autopilot standards. The third-generation flight control system will be open source innovation in software and artificial intelligence. It joined the cluster fly, image recognition, autonomous obstacle avoidance, automatic flight tracking and other advanced features flight, to machine vision, clustering, platform development process direction. You should not miss the open source flight control Legend
Arduino Flight Control
To talk about the development of the open source flight control we would have to talk from well-known open source hardware projects Arduino. Arduino is an open-source earliest flight control by Massimo Banzi, David Cuartielles, Tom Igoe, Gianluca Martino, David Mellis and Nicholas Zambetti in 2005, was developed in cooperation Italian Institute of Interaction Design. Arduino company first built a flexible open-source hardware platform and development environment for electronics hobbyists, users can get Arduino hardware design documents from the official website, the adjustment circuit boards and components to meet the needs of their actual design. Arduino can be viewed through its support of the Arduino IDE software source code and upload code that I have written, Arduino IDE using the Arduino language is based on C and C ++, and very easy to master, and the Arduino IDE can be in Windows, Macintosh OSX and Linux three It runs on major operating systems. As the platform is gradually accepted by fans, the various functions of the electronic expansion module after another, which is the most complex integrated MEMS sensor flight controller. To get a better flight control design source code, Arduino company decided to open its flight control source code, they opened the way open-source development of flight control. WMC-known open source flight control and flight control Arduino APM is a direct derivative products, still using the Arduino development environment for development.
APM Flight Control
APM (ArduPilotMega) was launched in 2007 by the DIY UAV community (DIY Drones) flight control products, is the most mature open source hardware projects. APM based Arduino open source platform, made of many hardware improvements, including accelerometers, gyroscopes and magnetometers of inertial measurement unit (IMU). As good APM customizable, APM spread rapidly on a global model aircraft enthusiasts range open. Mission Planner by open source software, developers can configure the settings for APM, accepts and displays sensor data, use google map complete autopilot and other functions, but the Mission Planner only supports windows operating system. Currently APM flight control flight control has become a mature open source benchmark that can support multi-rotor, fixed wing, helicopters and unmanned aerial vehicles and other unmanned devices. For multi-rotor, APM Flight Controller supports a variety of four, six, eight-axis products, and later be able to connect an external GPS sensor augmentation, and complete autonomous takeoff and landing, independent airline flight home, set high, fixed-point and other rich flight mode. APM ultrasonic flow sensor and a light sensor can be connected to external, and high in the room to achieve a given point of flight. PX4 and PIXHawk
PX4 is an open source hardware and software project (to comply with the BSD license), aims to provide a low cost for the academic, hobby and industry groups, high-performance high-end autopilot. The project stems from the Zurich Federal Institute of Technology Computer Vision and Geometry Lab, autonomous systems and laboratory automation laboratory PIXHawk project. PX4FMU autopilot modules running efficient realtime operating system (RTOS), Nuttx provide a Portable Operating System Interface (POSIX) type environment. For example: printf, pthreads, / dev / ttyS1, open, write, poll, ioctl like. Software can use USB bootloader update. PX4 by MAVLink same ground station communication, compatible ground stations have QGrounDControl and Mission Planner, all open source software and abide by the BSD license. 3DR APM Group and by the Joint PX4 group launched in 2014 PIXHawk flight control flight control is an upgraded version of PX4, PX4 and APM has two sets of firmware and the corresponding ground station software. The flight control flight control product is currently the world's highest in the hardware specifications of the product, is currently the hottest products in the hands of enthusiasts.
PIXHawk has the operating frequency of 168MHz, and breakthrough using integrated hardware floating point core Cortex-M4 microcontroller as the master chip, two built-in gyro and accelerometer MEMS sensor, complementary correction, built-axis magnetic field sensors and can add a triaxial magnetic field sensor, while the main one can add a two GPS sensors, automatic switching in case of failure.
Based on its core and high-speed floating-point arithmetic operations, PIXHawk use the most advanced high given algorithm, it can be fixed within 1 meter height alone barometric altimeter put aircraft. It supports almost all multi-rotor type, and even includes three rotors and H4 irregular structures such products. It makes a variety of aircraft has flight mode, support autonomous route, key points around the mouse guide, "FollowMe", the flight-to-tail and other senior flight mode, and the ability to complete independent parameter adjustment.
Open PIXHawk flight control very well, hundreds of parameters are all open to the players to adjust, after commissioning on the basis of a simple model can fly. PIXHawk integration of multiple electronic map enthusiasts can choose according to local conditions.
OpenPilot and Taulabs
OpenPilot by OpenPilot community launched in 2009 autopilot project, designed to provide low-cost but powerful stable autopilot for the community. The project consists of two parts, including OpenPilot autopilot its matching software. Among them, the firmware part autopilot is written in C language, and the ground station is written in C ++, and runs on Windows, Macintosh OSX and Linux three major operating systems. OpenPilot most important feature is hardware architecture is very simple, from a number of hardware design it can be seen currently has its unique place. The official release of the flight control hardware includes CC, CC3D, ATOM, Revolution, Revolution nano, etc., derived hardware includes Sparky, Quanton, REVOMINI, and even use the STM32 development board that contains a direct extension to the FlyingF3, FlyingF4, DescoveryF4, etc., which have been CC3D the following is a 300mm wheelbase and ultra-small through the machine of choice for indoor model aircraft flight control, and DiscoveryF4 been widely used in fans for flight control, Quanton is to become the first choice of hardware Taulabs. Below us, say Openpilot's most popular hardware CC3D. This flight control using only one plate of 72MHz and a 32-bit microcontroller STM32 MPU6000 can be completed four rotors, fixed wing, helicopter flight attitude control (note that the hardware is available for attitude control three degrees of freedom, rather than by stability), the board size of only 35mm × 35mm.
With all the open source flight control different, it does not require GPS or a magnetic field sensor fusion participate amended, attitude control can be maintained over time. All the above functions all use a firmware, you can change the settings by aircraft type, flight mode, support PTZ augmentation and other functions.
It compiled firmware required capacity is only about 100KB, code efficiency amazing, all flight control programmers learning model. Its ground station software integrates a complete electronic map, can be monitored in real time by radio condition of the aircraft.
TauLabs is OpenPilot flight control flight control of derivatives. Current TauLabs most popular hardware called the Quanton, former OpenPilot flight control team members independently.
It inherits the characteristics OpenPilot simple and efficient, and extends the barometric altimeter and a triaxial magnetic field sensor, the host microcontroller core Cortex-M4 upgraded with hardware floating-point operations. This was the first flight control parameter adjustment support automatic flight control of open-source product, with the model identification algorithm, capable of self-tuning PID control parameters attitude in flight. TauLabs able to complete many advanced flight mode, the GPS can connect an external multi-rotor with fixed high, fixed, home and other functions. Integrated flight control electronic map, and the interface is very friendly, wizard mode initialization, beginners can easily get started.
Multi Wii Copter (MWC) flight control is a typical Arduino derivative products, is designed for the development of low-cost multi-rotor flight control, it is to retain the integrity of the Arduino IDE Arduino development and use of methods and equipment upgrades. Due to the low cost, simple structure, firmware relatively mature, so the flight control has a lot of fans at home and abroad. In addition to supporting the common four, six, eight rotor outside, the most important feature of the flight control that supports many strange type of aircraft, such as a triple rotor, Avatar aircraft (BIcopter avatar style), Y4 multi-rotor (which the two-axis vertically on opposite ), etc., so that the flight control development interest is strong, easy to win everyone's favorite. KKMulti Copter
Autoquad flight control from Germany, as an early open source flight control, Autoquad very powerful, but limited by the time of the sensors, it had to use a lot of analog MEMS sensors.
The so-called analog sensor means is a sensor chip is not integrated internal digital to analog converter (ADC) and processor cores, will vary directly micromechanical sensor and hardware filtering the amplified voltage output in the form required by the master MCU AD acquisition.
Since the sensor at different temperatures, the output value will be affected, to simulate the MEMS sensor calibration parameters of a lot of trouble. Many players at the first use of the flight control, had to be carried out by means of refrigerator sensor calibration, and some manufacturers in order to ensure the stability of the product batch, only heating of the circuit board on the aircraft, to keep the temperature constant .
However, this calibration method has brought extra fun as some of the senior players, but a lot of people this way. For most ordinary fans, this really is a work of no small difficulty. With the popularity of digital sensors with factory-calibrated, Autoquad as the accumulation of history, also completed its mission.
However, another branch of the open source project ESC32 ESC has gradually been accepted in the player. The ESC is the first digital interface control power transfer products, the player can control the motor speed through the serial port, I2C and CAN interface, which is many times faster than conventional PWM speed interface information. ESC common PWM waveform update rate of four hundred per second, while the update speed digital interface can reach millions. Especially for powerThis high-speed communication is very necessary to change very sensitive multi-rotator. The electrical tone also supports the speed shuttle and can be adjusted for the motor for detailed adjustments, which are unmatched by conventional model electrical tones.
Of course, AutoQuad is also progressing, which released a new flying control product Autoquad M4, which has been fully upgraded to the main control microcontroller and sensor, using common STM32F4 microcontroller and digital sensor. But in the face of Pixhawk, APM, etc. has been mature for many years, it has fallen from the elders as the show.
WeChat public number search "" Love Board Network "", pay attention, daily latest development board, intelligent hardware, open source hardware, activities, etc., you can make you full. Recommended attention!
[WeChat scanning picture can be directly paid]
Related reading:
Take you to spyken - TPU / NPU / CPU / GPU under artificial intelligence
The omnipotent Raspberry Party, let the engineers are incomparable? "
Our other product:
