CN113391589B

CN113391589B - Unified access and protocol conversion integrated circuit board for heterogeneous equipment of unmanned aerial vehicle

Info

Publication number: CN113391589B
Application number: CN202110727282.5A
Authority: CN
Inventors: 李晓娟; 周兴社; 张羽; 吕双超; 林满; 姚远; 刘慧霞
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2022-12-27
Anticipated expiration: 2041-06-29
Also published as: CN113391589A

Abstract

The invention provides a unified access and protocol conversion board card for heterogeneous equipment of an unmanned aerial vehicle, which comprises an FPGA module, a power supply module, a clock module, a photoelectric conversion module, a storage module, an interface circuit module and a connector module; the board card supports SDI, CAN, asynchronous RS422, synchronous RS422, 1000Base-T Ethernet port, optical fiber Rapid and PCIe interface; the board card provides a PCIe interface as a uniform interconnection interface of the access board card and a main processing card of the task computer; the board card supports the conversion of the physical level of each interface into a general TTL level; the board card supports the physical layer protocol and transmission protocol analysis of various interfaces; the board card supports parallel data receiving and sending of various interfaces. The invention meets the requirement of diversification of the interface of the airborne equipment; the design and development of the equipment access system are simplified; the efficiency of data transmission between the devices is improved; supporting flexible use of the load device.

Description

Unified access and protocol conversion integrated circuit board for heterogeneous equipment of unmanned aerial vehicle

Technical Field

The invention relates to the field of airborne computers of unmanned aerial vehicles, in particular to a unified access and protocol conversion board card for airborne heterogeneous equipment of an unmanned aerial vehicle.

Background

Existing drone systems typically require the interconnection of a variety of sub-devices, including flight control devices, mission computers, communication devices, and a large number of mission loads (devices equipped to the aircraft to accomplish some kind of mission). In the traditional method, devices needing interconnection are connected in a point-to-point mode, for example, an asynchronous RS422 interface is adopted to connect devices with small data volume transmission, and a synchronous RS422 interface is adopted to connect devices with large data volume transmission; or the equipment is connected to a main control computer by adopting a bus technology. With the improvement of processing performance of the onboard computer and the development of the onboard equipment, the existing interconnection method of the onboard equipment cannot meet the requirement of an onboard system.

In recent years, unmanned aerial vehicle systems are rapidly developed, and besides various devices and task computers need to be interconnected, more and more kinds of task loads need to be carried, so that different application functions are realized, and the demand that the unmanned aerial vehicle realizes multifunctional integration by simultaneously loading various loads is met. The types of equipment interfaces are different, and the fixed static interface types and the fixed static interface number of the existing system cannot meet the requirements of various interface types and numbers and dynamic variability; secondly, the communication topology between the airborne equipment of the unmanned aerial vehicle is determined in the design process aiming at specific application, different software and hardware systems need to be designed for different equipment in the process of adapting the equipment, once the equipment is replaced and added, a hardware interface circuit and a corresponding driving program need to be redesigned, the system maintenance cost is high, and the equipment is difficult to be compatible.

The unmanned aerial vehicle system connects multiple heterogeneous equipment, and the equipment interface is various, but unmanned aerial vehicle's bearing capacity is limited, and task execution can not carry on all equipment, and the interface type that the unified access board supports limit kind and quantity.

Disclosure of Invention

In view of the above defects, in order to solve the problems in the prior art, the invention aims to provide an access board for unified access of unmanned aerial vehicle-mounted equipment to an unmanned aerial vehicle task computer, so that the unmanned aerial vehicle can carry heterogeneous and heterogeneous multiple devices through the unified access board, the access system time is faster, the development time is shorter, the data transmission efficiency is higher, and the devices can be flexibly loaded and replaced.

The technical scheme of the invention is as follows: a unified access and protocol conversion board card for heterogeneous equipment of an unmanned aerial vehicle comprises an FPGA module, a power supply module, a clock module, a photoelectric conversion module, a storage module, an interface circuit module and a connector module; the board card supports SDI, CAN, asynchronous RS422, synchronous RS422, 1000Base-T Ethernet port, optical fiber Rapid and PCIe interface; the board card provides a PCIe interface as a unified interconnection interface of the access board card and a main processing card of the task computer; the board card supports the conversion of the physical level of various interfaces into a universal TTL level; the board card supports the physical layer protocol and transmission protocol analysis of various interfaces; the board card supports parallel receiving and sending of data of various interfaces.

Further, the unified access and protocol conversion board card of the heterogeneous equipment of the unmanned aerial vehicle supports data receiving and sending of the synchronous RS422, the asynchronous RS422 and the CAN interface through a PCIe data channel, the size of a single transmission data block is specified by a user and is 4KByte at the maximum, and complete transmission of an equipment data frame is ensured. The board card supports SDI and 1000Base-T, rapid board interfaces to receive and transmit data through a PCIeDMA data channel, the size of a data block transmitted at a time is 4KByte, and transmission of equipment data is guaranteed.

Further, the unified access and protocol conversion board card of the heterogeneous equipment of the unmanned aerial vehicle supports transparent data transmission from one path of synchronous RS422 to another path of synchronous RS422 interface.

Further, the unified access and protocol conversion board card of the heterogeneous unmanned aerial vehicle device supports PCIe interface for protocol conversion of the device access interface.

Further, the unified access of the heterogeneous equipment of the unmanned aerial vehicle and the corresponding Linux driver of the protocol conversion board card provide data receiving and sending operations of a PCIe interface driver and an equipment interconnection interface.

Further, an interface of the unmanned aerial vehicle heterogeneous device, which is uniformly connected to the protocol conversion board card and connected with the airborne device, detects that data is received, the interface controller performs protocol analysis on the received data, extracts effective data from an interface data packet or a data frame, and writes the data into a data cache. Each interface corresponds to an independent data receiving storage space, the interface receives data, writes the data into the data buffer area, changes the buffer state and triggers an interrupt to be sent to the PCIe, and the PCIe controller receives the interrupt, judges the interface to which the received data belongs, reads the data from the corresponding interface, packages a data packet of a PCIe protocol, and sends the data through the PCIe controller.

Further, when an onboard task computer sends data to certain onboard equipment, a PCIe data packet carrying the sent data is sent to a board interface card, a PCIe controller receives the data, PCIe protocol analysis is carried out on the data, effective data are extracted, a target interface of the data is checked, and the data are written into a sending buffer area of a corresponding interface; and the interface controller starts data to be sent to the connecting equipment, extracts the data from the corresponding buffer, performs protocol encapsulation and sends the data according to the protocol format of the corresponding interface.

Further, the connector module realizes external interconnection, and the connector is a VPX connector.

Further, the FPGA module comprises a logic part and an ARM part; the ARM part connects the controller with the logic function part through asynchronous interconnection management; and each memory of the logic part carries out secondary synchronization on data of different interfaces.

The invention provides a unified access and protocol conversion board card for heterogeneous equipment of an unmanned aerial vehicle, which provides a set of software and hardware scheme, and can enable various airborne equipment and an airborne task computer to be seamlessly connected together, such as flight control equipment, data terminal equipment, task load and the like, and data exchange is carried out between the equipment through protocol conversion of a unified access board. Compared with the prior art, the invention supports airborne equipment with various interfaces, including synchronous RS422, asynchronous RS422, SDI, CAN, 1000Base-T, rapidIO, and meets the demand of airborne equipment interface diversification; the design development of the equipment access system is simplified, and the equipment access system is designed once and reused; the efficiency of data transmission between the devices is improved; supporting flexible use of the load device.

Drawings

Fig. 1 is a schematic diagram of a unified access and protocol conversion board card module of an unmanned aerial vehicle heterogeneous device;

fig. 2 is a schematic diagram of a circuit module of a unified access and protocol conversion board card interface of an unmanned aerial vehicle heterogeneous device;

fig. 3 is a schematic diagram illustrating an implementation principle of an unmanned aerial vehicle heterogeneous device unified access and protocol conversion board FPGA module;

fig. 4 is a schematic diagram of a data processing flow implemented by a unified access and protocol conversion board FPGA module of an unmanned aerial vehicle heterogeneous device;

fig. 5 is a schematic diagram of protocol conversion of an unmanned aerial vehicle heterogeneous device unified access and protocol conversion board card based on an FPGA.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, a unified access and protocol conversion board card for heterogeneous devices of an unmanned aerial vehicle comprises an FPGA module, a power module, a clock module, a photoelectric conversion module, a storage module, an interface circuit module, and a connector module; the board card supports SDI, CAN, asynchronous RS422, synchronous RS422, 1000Base-T Ethernet port, optical fiber Rapid and PCIe interface; the board card provides a PCIe interface as a uniform interconnection interface of the access board card and a main processing card of the task computer; the board card supports the conversion of the physical level of various interfaces into a universal TTL level; the board card supports the physical layer protocol and transmission protocol analysis of various interfaces; the board card supports parallel data receiving and sending of various interfaces.

The existing small unmanned aerial vehicle has PPM, SBUS, serial port (including TTL,232, 422, 485), SPI, I2C, CAN, USB and the like at the equipment interface, and the equipment interface of the medium-sized and large-sized unmanned aerial vehicle refers to an airborne data bus. Wherein, the medium and low speed data bus has: the STD-1553B data bus is used for a multi-channel data bus of time division commands in the aircraft; ARINC429 data bus for transmitting digital information; an RS485 data bus; the synchronous RS422 data bus and the asynchronous RS422 data bus are used for serial transmission of digital information; the CAN bus is used for establishing a thread bus of the controller area network; and so on. The medium-high speed data bus has: an IEEE1394 data bus for high performance serial data transmission; the SDI data bus is used for transmitting video data; and so on. The high-speed data bus has: the AFDX bus can carry out high-speed transmission on data, images and multimedia services by the avionic full-duplex switched Ethernet; triggering an Ethernet data bus by TTE time; the Ethernet data bus has simple network and high data transmission reliability. Considering that a medium-large unmanned aerial vehicle has more requirements for task replacement equipment and covers application requirements of the medium-large unmanned aerial vehicle for reconnaissance by using radars and cameras, designing a device unified access board card supporting limited types and covering more applications, selecting an RS422 interface, a CAN interface and an SDI interface as interface types supported by the interface board, connecting SAR radars through RS485 or RS422 interfaces, connecting flight control equipment mainly through the CAN interfaces, connecting video equipment mainly through the SDI interfaces, and selecting an Ethernet interface as an inter-system interconnection interface of the unmanned aerial vehicle, thereby realizing supporting application coverage as much as possible by limited resources.

1. Power module, clock module, memory module

The power module, the clock module and the storage module belong to a function support module and provide necessary conditions for realizing functions.

1. Power supply module

The power module provides power support for the whole board, and the 12V input is converted into a required power supply of each chip in the board by adopting DC-DC (direct current-direct current): +1.0V, +3.3V, +2.5V, +1.8V, +1.5V, +1.2V.

2. Clock module

The clock module generates the required 50MHz, 100MHz, 125MHz, 185MHz, 184.35MHz and 25MHz clocks for the FPGA.

3. Memory module

The storage module provides external storage for the FPGA, comprises NorFlash and is used for storing the FPGA to load the configuration file in parallel; the EEPROM is used for storing the FPGA serial loading configuration file; DDR3, ARM running program for FPGA.

2. Photoelectric conversion module, interface circuit module and FPGA module

The photoelectric conversion module, the interface circuit module and the FPGA module belong to the functional module of the access board card.

1. Photoelectric conversion module

The photoelectric conversion module converts the Rapid board electric signal of the FPGA into an optical signal.

2. Interface circuit module

The interface circuit module adopts an interface chip to realize the physical layer signal conversion of CAN, SDI, RS232, asynchronous RS422 and synchronous RS422 interfaces, and the converted signal CAN be connected with the FPGA.

The interface circuit module includes a circuit portion for performing physical layer signal conversion for different interfaces, as shown in fig. 2. The 1000Base-T interface circuit is composed of an Ethernet PHY and a network transformer, the Ethernet PHY realizes the conversion from RGMII signals of the FPGA to 1000Base-T signals of the network interface, and the network transformer enhances the signals, protects a chip and improves the anti-interference capability. The synchronous RS422 and asynchronous RS422 interface circuit comprises an RS422 receiving circuit and an RS422 generating circuit, the RS422 receiving circuit converts the differential RS422 level signal into a single-end receiving signal, and the RS422 generating circuit converts the single-end transmitting signal into a differential signaling conforming to the RS422 standard. The synchronous RS422 and the asynchronous RS422 use the same circuit, and the synchronous RS422 converts the clock signal more than the asynchronous RS 422. The CAN interface circuit comprises a CAN isolation transceiver circuit, the CAN isolation transceiver circuit realizes the transceiving and isolation of CAN signals, converts the logic level of a CAN controller into the differential level of a CAN bus and has the isolation function. The SDI interface circuit comprises an SDI cable equalizer and rectifies an SDI signal.

3. FPGA module

The FPGA module is a core module of the whole access board card, and all functions except signal physical layer conversion are realized.

The FPGA module takes an FPGA chip as a core, and the FPGA has the following characteristics: support for

The core-A9 core is provided with a large number of logic units, supports a high-speed transceiver, supports PCIe and supports a DDR memory interface. The FPGA module comprises two parts, a logic part and an ARM part, and the module is formed and realized as shown in figure 3. The ARM part realizes asynchronous RS422, RS232, CAN and 1000Base-T controllers and connects the controllers with the logic function part through asynchronous interconnection management. The logic part realizes the secondary synchronization of SDI, rapid board, synchronous RS422 controller, FIFO memory, data buffer memory, FIFO memory and data buffer memory to different interfaces. A large amount of data of 1000Base-T, SDI and RapidIO interfaces are stored in corresponding DDR memory space through a multiplexing selector realized through logic. Meanwhile, the logic realizes the storage monitoring of each interface and is used for generating PCIe interrupt. The PCIe controller is also implemented by logic for receiving the interrupt read data and sending out the data or writing the received data into the corresponding interface for storage and generating an interrupt.

And the FPGA logic realizes the mapping relation between the data received by the interface board interconnection equipment through different types of interfaces and the PCIe data packet through PCIe interrupt buffering. When the device interface buffer is full, generating PCIe interrupt with different interrupt numbers, buffering the PCIe interrupt, determining an interrupt source by the PCIe controller according to the PCIe interrupt numbers, receiving data buffer reading data from different devices to form a PCIe data packet, and adding a device interface identifier in the PCIe data packet. And one-to-one data receiving and sending are realized by establishing a mapping relation.

The interface controller and the buffer of the interface board card FPGA jointly realize the conversion of an interface protocol, and the interface protocol comprises PCIe-CAN, PCIe-synchronous RS422, PCIe-asynchronous RS422, PCIe-1000Base-T, PCIe-SDI and PCIe-Rapid boards. As shown in fig. 5.

3. Connector module

The connector modules realize external interconnection, and the connector is in the form of a VPX connector.

It is worth pointing out that, in this embodiment, the board card supports data transceiving of the synchronous RS422, the asynchronous RS422, and the CAN interface through the PCIe data channel, the size of the data block for single transmission is specified by the user, and is 4KByte maximum, and complete transmission of the device data frame is ensured. The board card supports SDI and 1000Base-T, rapid board interfaces to receive and transmit data through a PCIeDMA data channel, the size of a data block transmitted at a time is 4KByte, and transmission of equipment data is guaranteed.

The equipment unified access board card supports data transmission between one path of synchronous RS422 and the other path of synchronous RS422, that is, data is directly transmitted between two synchronous RS422 interfaces without passing through a task computer during data receiving and transmitting.

The board card supports PCIe interface for protocol conversion of equipment access interface. The board card is provided with a corresponding Linux drive program and provides data receiving and transmitting operation of a PCIe interface drive and an equipment interconnection interface.

The processing flow of the FPGA on the data in the invention is shown in FIG. 4. The interface of connecting airborne equipment detects that there is data reception, and interface controller carries out protocol analysis to the received data, draws valid data from interface data package or data frame, writes into data cache with data, and the mode of writing into data cache to different interfaces is different: the CAN, asynchronous RS422 and RS232 interface controllers are realized by ARM, received data are firstly written into FIFO realized by logic through data interconnection management and then written into a data buffer, and secondary synchronization is carried out on the data; the 1000BASE-T controller is also realized by ARM, and data transfer is carried out by adopting a DMA mode; the SDI and Rapid board controllers are realized by logic, and data of three high-speed interfaces of 1000BASE-T, SDI and Rapid boards are written into the DDR memory through a high-speed multiplexing selection switch; the synchronous RS422 interface controller is realized by logic, and received data is directly written into the data buffer. Each interface corresponds to an independent data receiving storage space, the interface receives data, writes the data into the data buffer area, changes the buffer state and triggers an interrupt to be sent to the PCIe, and the PCIe controller receives the interrupt, judges the interface to which the received data belongs, reads the data from the corresponding interface, packages a data packet of a PCIe protocol, and sends the data through the PCIe controller.

When an airborne task computer sends data to certain airborne equipment, a PCIe data packet carrying the sent data is sent to a board interface card firstly, a PCIe controller receives the data, PCIe protocol analysis is carried out on the data, effective data are extracted, a target interface of the data is checked, and the data are written into a sending buffer area corresponding to the interface: if the interface is CAN, asynchronous RS422 and RS232 interface, the data are transmitted to the corresponding interface controller through data interconnection management, ARM interrupt is generated, the ARM is notified, and the interface controller sends data to the equipment; if the interface is a 1000BASE-T, SDI and Rapid board interface, writing valid data into a corresponding address of the DDR memory, detecting the data by an interface controller, and starting data transmission; if the interface is the synchronous RS422 interface, the valid data is written into the corresponding data buffer, and the synchronous RS422 interface controller directly reads the data from the data buffer for sending. And the interface controller starts data to be sent to the connecting equipment, extracts the data from the corresponding buffer, performs protocol encapsulation and sends the data according to the protocol format of the corresponding interface.

Claims

1. A unified access and protocol conversion board card for heterogeneous equipment of an unmanned aerial vehicle comprises an FPGA module, a power module, a clock module, a photoelectric conversion module, a storage module, an interface circuit module and a connector module; the method is characterized in that: the board card supports SDI, CAN, asynchronous RS422, synchronous RS422, 1000Base-T Ethernet port, optical fiber Rapid and PCIe interface;

the board card provides a PCIe interface as a uniform interconnection interface of the access board card and a main processing card of the task computer;

the board card supports the conversion of the physical level of various interfaces into a universal TTL level;

the board card supports the physical layer protocol and transmission protocol analysis of various interfaces;

the board card supports the parallel receiving and sending of data of various interfaces;

the board card supports a PCIe interface for protocol conversion of a device access interface;

the board card is provided with a corresponding Linux drive program and provides PCIe interface drive and data transceiving operation of an equipment interconnection interface;

the interface controller performs protocol analysis on the received data, extracts effective data from an interface data packet or a data frame, and writes the data into a data cache;

each interface corresponds to an independent data receiving storage space, the interface receives data, writes the data into a data buffer area to change a buffer state and triggers an interrupt to be sent to PCIe, and the PCIe controller receives the interrupt, judges the interface to which the received data belongs, reads the data from the corresponding interface, performs data packet encapsulation of a PCIe protocol, and sends the data through the PCIe controller;

when an airborne task computer sends data to certain airborne equipment, a PCIe data packet carrying the sent data is sent to a board interface card, a PCIe controller receives the data, carries out PCIe protocol analysis on the data, extracts effective data, checks a target interface of the data, and writes the data into a sending buffer area of a corresponding interface; and the interface controller starts data to be sent to the connecting equipment, extracts the data from the corresponding buffer, performs protocol encapsulation and sends the data according to the protocol format of the corresponding interface.

2. The unified access and protocol conversion board card of the heterogeneous equipment of unmanned aerial vehicle of claim 1, characterized in that: the board card supports data receiving and sending of the synchronous RS422, the asynchronous RS422 and the CAN interface through a PCIe data channel, the size of a single transmission data block is specified by a user and is 4Kbyte at most, and complete transmission of a device data frame is guaranteed.

3. The unified access and protocol conversion board card of the heterogeneous equipment of unmanned aerial vehicle of claim 1, characterized in that: the board card supports SDI and 1000Base-T, rapid board interfaces to receive and transmit data through a PCIeDMA data channel, the size of a data block transmitted at a time is 4KByte, and transmission of equipment data is guaranteed.

4. The unified access and protocol conversion board card of the heterogeneous equipment of unmanned aerial vehicle of claim 1, characterized in that: the board card supports transparent data transmission from one path of synchronous RS422 to the other path of synchronous RS422 interface.

5. The unified access and protocol conversion board card of the heterogeneous equipment of unmanned aerial vehicle of claim 1, characterized in that: the connector module realizes external interconnection, and the connector is in a VPX connector form.

6. The unified access and protocol conversion board card of the heterogeneous equipment of unmanned aerial vehicle of claim 1, characterized in that: the FPGA module comprises a logic part and an ARM part; the ARM part connects the controller with the logic function part through asynchronous interconnection management;

and each memory of the logic part carries out secondary synchronization on data of different interfaces.