KR102173535B1 - Embedded board based on android enhenced real time response - Google Patents

Abstract

The present invention relates to an Android-based embedded board with improved real-time performance. According to the present invention, the Android-based embedded board with improved real-time performance comprises: a board which operates based on an Android operating system; a CPU installed on the board to control the board; a network card; and a case having the board installed therein. According to the present invention, real-time performance can be significantly improved.

Description

Android-based embedded board with improved real-time performance {EMBEDDED BOARD BASED ON ANDROID ENHENCED REAL TIME RESPONSE}

The present invention relates to an Android-based embedded board, and more specifically, the kernel layer of the Android operating system is composed of a real-time kernel and a real-time dual kernel of a non-real-time kernel, so that real-time performance is improved and other devices It relates to an Android-based embedded board with improved real-time performance that is compatible with the system.

The embedded board refers to a board used in embedded systems used in the entire industry, from factory automation machines to kiosks.

Existing embedded boards were prepared in the x86 series corresponding to Microsoft's Windows operating system, but the x86 series of embedded boards has a problem that the price of the entire device increases because the Windows operating system must be separately purchased.

Accordingly, Android, an open platform, is attracting attention as an operating system of an embedded system, and demands for applications in the industrial control systems (ICS) field are also increasing.

In accordance with this trend, manufacturers of embedded boards are developing and manufacturing various systems using the form factor of the ARM series corresponding to the Android operating system.

However, since Android was developed for the purpose of providing a platform for a mobile device, there is a problem in that it does not have the real-time processing capability required in the industrial control system field, and it has low compatibility with other devices.

An object of the present invention is to solve the above-described conventional problem, and the kernel layer of the Android operating system is composed of a real-time kernel and a real-time dual kernel, thereby improving real-time performance and It is to provide an Android-based embedded board with improved real-time performance with high device compatibility.

The object is, according to the present invention, a board operated based on the Android operating system; A CPU installed on the board and controlling the board; A network card installed on the board so that the board can exchange information with an external device, and configured to correspond to an EtherCAT (Ethernet for Control Automation Technology) communication method; And a case in which the board is installed therein, wherein the CPU is provided with an ARM-series CPU, and the kernel layer constituting the operating system is provided with a Linux kernel to process a non-real-time task. And, a real-time kernel formed by transplanting Xenomai into the Linux kernel and processing a real-time task received through the EtherCAT communication method independently from the non-real-time kernel, wherein the real-time kernel is It has a higher priority, and the EtherCAT master in the EtherCAT communication method is provided as an IgH EtherCAT master and is interlocked with the network device driver through a generic driver method, and the board is a flow path through which water can be moved. And a dehumidifying unit installed on the substrate to be connected to the flow path and collecting and condensing water vapor inside the case, and a dehumidifying unit disposed under the CPU and installed on the substrate to be exposed to the flow path, A heat dissipation part that absorbs heat generated from the CPU by vaporizing water supplied from the flow path, and a discharge that is installed on the substrate and forms a discharge passage so that the steam vaporized from the heat dissipation part can be discharged to the outside of the case Real-time performance including wealth is achieved by an improved Android-based embedded board.

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In addition, the board may be provided in a Mini-ITX form factor.

According to the present invention, an embedded board with significantly improved real-time performance required in the industrial control system field can be provided.

In addition, according to the present invention, there is an effect that it can be mounted in a case corresponding to the form factor of the x86 series Mini-ITX used in conventional industrial sites.

Meanwhile, the effects of the present invention are not limited to the above-mentioned effects, and various effects may be included within a range that will be apparent to a person skilled in the art from the contents to be described below.

1 is a diagram showing the overall configuration of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention,
2 shows a hierarchical structure of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention,
3 is a diagram illustrating a communication process between Android and Xenomai of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating the structure of an IgH EtherCAT Master, a network device driver, and a generic device driver of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention.
5 is a graph and a table showing an analysis result of a task periodicity of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention.
6 is a diagram illustrating an experimental process of an Android-based embedded board with improved real-time performance and a performance analysis result for an EtherCAT Control Task according to an embodiment of the present invention.
7 is a conceptual diagram and analysis result of the execution time of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention.
8 is a diagram illustrating an insertion module 110a of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention,
9 illustrates a board of an Android-based embedded board with improved real-time performance according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, it should be noted that the same elements are assigned the same numerals as possible even if they are indicated on different drawings.

In addition, in describing an embodiment of the present invention, if it is determined that a detailed description of a related known configuration or function interferes with an understanding of the embodiment of the present invention, a detailed description thereof will be omitted.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the embodiment of the present invention. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term.

Hereinafter, with reference to the accompanying drawings, an Android-based embedded board 100 with improved real-time performance according to an embodiment of the present invention will be described in detail.

1 is a diagram showing the overall configuration of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention, and FIG. 2 is a layer of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention. 3 is a diagram illustrating a communication process between Android and Xenomai of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention, and FIG. 4 is a real-time diagram according to an embodiment of the present invention. The structure of the IgH EtherCAT Master, the network device driver, and the generic device driver of an Android-based embedded board with improved performance is shown. FIG. 5 is a diagram of a task of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention. The analysis results for periodicity are shown in graphs and tables, and FIG. 6 shows the experimental process of the Android-based embedded board with improved real-time performance according to an embodiment of the present invention and the performance analysis results for the EtherCAT Control Task, 7 is a conceptual diagram and analysis result of the execution time of an Android-based embedded board with improved real-time performance according to an embodiment of the present invention, and FIG. 8 is an Android-based Android-based with improved real-time performance according to an embodiment of the present invention. It shows the insertion module (110a) of the embedded board.

As shown in FIG. 1, an Android-based embedded board 100 with improved real-time performance according to an embodiment of the present invention includes a board 110, a CPU 120, and a network card 130.

The board 110 is operated based on the Android operating system, is provided with a printed circuit board (PCB), and a CPU 120 and a network card 130 to be described later are installed. The board 110 may be used to control industrial automation devices such as machine tools and robots, and may be used to control special devices used in general industries such as kiosks and bus billboards.

This board 110 transfers data from the network card 130 to be described later to the CPU 120 to be described later, or transfers the data processed by the CPU 120 to the network card 130, which is a Mini-ITX form factor standard. It is provided with.

The Mini-ITX form factor standard is prepared in an area of 17cm*17cm, and is the most widely distributed standard as a small board equipped with Intel's x86 series CPU. However, since the ARM series embedded board on which the Android operating system is mounted has a different area from the above-described x86 series form factor standard, the ARM series of the ARM series are installed in the case (Mini-ITX form factor standard case) where the conventional x86 series board is mounted. Since it is impossible to mount an embedded board, there is a problem in that a case corresponding to the form factor standard of the ARM series must be separately manufactured when using the ARM series embedded board.

Accordingly, according to the board 110 provided in the Mini-ITX form factor standard, an embedded board capable of being mounted in a case corresponding to the conventional x86 series Mini-ITX form factor is provided.

On the other hand, the operating system (OS) installed on the above-described board 110 is provided with Android, which has greater openness and lower price than Windows, and mobile devices and other various systems It is an open source platform that is widely used in

In this case, as shown in FIG. 2, the kernel layer constituting the Android operating system includes a real-time kernel R for processing real-time tasks transmitted and received through the EtherCAT protocol, and a non-real-time kernel for processing non-real-time tasks. It is composed of (NR) Real-Time Dual Kernel structure.

In more detail, here, the non-real-time kernel (NR) means the existing Linux kernel (hereinafter referred to as'Linux kernel'), and the real-time kernel (R) is a kernel formed by transplanting Xenomai to the existing Linux kernel ( Hereinafter referred to as'Xenomai kernel').

Xenomai is a development framework to support real-time elements in Linux, and Xenomai provides a variety of real-time application programming interfaces (APIs) to a Linux-based platform to build a real-time operating system environment based on Linux.

Through Xenomai's porting, the kernel layer in the Android operating system has a Real-Time Dual Kernel structure. The real-time dual kernel refers to a structure in which a Linux kernel that processes non-real-time tasks or threads and a Xenomai kernel that processes real-time tasks or threads coexist and run.

In order to implement the dual kernel structure of the Linux kernel and the Xenomai kernel, first, the ADEOS/I-Pipe kernel patch for managing real-time tasks independently of the Linux kernel must be applied to the existing Linux kernel. Here, ADEOS (Adaptive Domain Environment for Operating System) refers to a resource virtualization layer that allows each domain to operate on the same hardware platform. ADEOS domains receive system-generated tasks through pipelines. Tasks delivered through the pipeline are gradually reduced from the higher priority domain to the lower priority domain.

After the aforementioned ADEOS/I-Pipe kernel patch, when Xenomai is transplanted to the existing Linux kernel, the Linux kernel and the Xenomai kernel coexist. At this time, the Xenomai kernel (that is, the real-time kernel (R)) becomes the Linux kernel (that is, , Non-real-time kernel (NR)) has a higher priority, so that the task created in the system is received first.

According to the board 110 as described above, since real-time tasks transmitted and received through the EtherCAT protocol can be effectively processed, real-time performance of the embedded board is improved.

On the other hand, between Android applications, IPC (Inter-Process Communication) can be implemented through AIDL (Android Interface Definition Language), but the aforementioned Xenomai kernel is a separate kernel that also uses memory space through ADEOS. Communication is impossible. Therefore, as shown in FIG. 3, using the Cross-Domain Datagram Protocol (XDDP), which is a communication protocol between a real-time task and a non-real-time task, can effectively implement a communication interface between Android and Xenomai.

The CPU 120 is installed on the board 110 to control the board 110 and is provided as an ARM-based CPU 120. Here, the ARM series is a series of CPU 120 in the form of RISC (Reduced Instruction Set Computer) manufactured by ARM Holdings, a manufacturer of CPU 120 in the UK, and uses about 95% or more of the mobile CPU 120 processor. It is occupied CPU 120 series. It is known that the ARM-based CPU 120 is inexpensive and consumes low power to produce high efficiency.

The CPU 120 performs a function of controlling an external device by exchanging data with an external device through the above-described board 110 and a network card 130 to be described later.

The network card 130 allows the board 110 to exchange data with an external device, and is installed on the board 110.

In more detail, the network card 130 receives data from the board 110 and transmits it to an external device, or receives data from an external device and transmits the data to the board 110. The network card 130 It is prepared to correspond to the EtherCAT (Ethernet for Control Automation Technology) communication method.

EtherCAT refers to a communication method between a master and a slave using Real-Time Ethernet, and is known to have features such as guaranteed real-time data transmission time, high transmission bandwidth, and high-precision synchronization using a distributed clock technique.

On the other hand, the EtherCAT master in the EtherCAT communication method is provided as an IgH EtherCAT master. In other words, EtherCAT communication is achieved by interlocking the IgH EtherCAT master with the network device driver.

IgH EtherCAT Master is compatible with real-time Linux such as Xenomai, RTAI and RT_PREEMPT, and is known to provide real-time device drivers for various Ethernet devices.

At this time, the IgH EtherCAT master and the network device driver are interlocked through the generic driver method.

In more detail, as shown in FIG. 4, the generic driver method is a method in which the IgH EtherCAT master stack and the network device driver are interlocked using a generic driver. In other words, the generic driver method is to additionally use the generic driver, that is, the EtherCAT driver, without modifying the Ethernet driver. According to this generic driver method, it is possible to implement EtherCAT communication without additional modification of the network device driver.

In order to verify the real-time performance of the Android-based embedded board 100 with improved real-time performance of the present invention, experiments were performed in the following specifications.

CPU(120) I.MXD SabreSD Android Android 6.0.1 Marshmallow Kernel Android Linux 4.1.15 Real-time OS Xenomai 3.0.7 ADEOS/I-Pipe ipipe-core-4.1.18-arm-9 EtherCAT Master IgH EtherCAT Master 1.5.2 Toolchain arm-linux-androideabi-4.9

First, the real-time performance of the Android-based embedded board 100 with improved real-time performance of the present invention was analyzed through a latency test provided by the Xenomai user library. Latency test is to check the periodicity of tasks performed during the set runtime. In this experiment, the runtime was set to 1 hour and the task was set to 1 ms. Jitter means the difference between the actual period of the current task and the set period.

As shown in FIG. 5, when the average, maximum, minimum and deviation of the jitter are analyzed, the results are shown in the table, and the figure shows the distribution of the results.

In addition, as shown in (a) of FIG. 6, the four EtherCAT slaves are connected to the Android-based embedded board 100 with improved real-time performance of the present invention with CAT8 gigabyte LAN cables. After that, the Velocity Profile is created in Xenomai ProfileTask based on the target speed set in the Android GUI application. It transfers this to the EtherCAT Control Task, drives each EtherCAT slave every 1ms, and records the result of performance analysis for the EtherCAT Control Task for 10 minutes.

As shown in (b) of FIG. 6, it can be seen that the value actually measured by the encoder of each device through the EtherCAT Control Task tracks the Velocity Profile value (reference value) created in the ProfileTask.

7(a), Expected Cycle means the set period of real-time task, Actual Cycle means the actual period of real-time task, and Execution Time is a new Dataframe from the time EtherCAT Dataframe is received from the buffer of the Ethernet device. It means the time it takes to send it to the buffer of the Ethernet device after making it, and Jitter means the difference between the actual cycle of the real-time task and the set cycle.

As shown in (b) of FIG. 7, it can be seen that the real-time performance of the Android-based embedded board 100 with improved real-time performance of the present invention is guaranteed according to the average and deviation values of the EtherCAT Control Task.

According to the Android-based embedded board 100 with improved real-time performance according to an embodiment of the present invention including the board 110, CPU 120 and network card 130 as described above, in the field of industrial control systems An embedded board with significantly improved real-time performance required can be provided.

In addition, according to the present invention, there is an effect that it can be mounted in a case corresponding to the form factor of the x86 series Mini-ITX used in conventional industrial sites.

On the other hand, the fastening member is coupled to the insertion hole formed in the board 110 in the form of a screw, and if the fastening member is repeatedly screwed for maintenance, the diameter of the insertion hole increases, so that the fastening member cannot be firmly coupled and the board ( 110) may shake.

Therefore, as shown in FIG. 8, if the insertion hole is formed in a separate insertion module 110a, and the insertion module 110a is configured to be detachably inserted into the board 110 in a sliding manner, maintenance is performed. When the diameter of the insertion hole increases due to the repeated detachment of the board 110 for repetitive attachment, the existing board 110 can be continuously used by replacing only the insertion module 110a without replacing the entire board 110. There is an effect.

Meanwhile, an elastic member 110b may be installed around the insertion hole on the upper or lower surface of the insertion module 110a. At this time, the elastic member (110b) is preferably provided with a high heat-resistant material to withstand the elevated temperature of the board (110). Accordingly, when the insertion module 110a is fastened to the case by the fastening member, it can be effectively prevented that the insertion module 110a is damaged by an external force applied to the fastening member.

Further, a plurality of positive/negative patterns may be formed on the bottom surface of the elastic member 110b. Accordingly, since the frictional force of the bottom surface of the elastic member 110b is increased, there is an effect that the fastening member can more stably fix the insertion module 110a and the case.

From now on, an Android-based embedded board 200 with improved real-time performance according to another embodiment of the present invention will be described.

9 is a diagram illustrating a board of an Android-based embedded board 200 with improved real-time performance according to another embodiment of the present invention.

Android-based embedded board 200 with improved real-time performance according to another embodiment of the present invention includes a board 210, a CPU 120, a network card 130, and a case in which the board 210 is installed. .

Here, since the CPU 120 and the network card 130 are the same as the Android-based embedded board 100 having improved real-time performance according to an embodiment of the present invention, a redundant description will be omitted.

The board 210 is operated based on the Android operating system and is provided with a printed circuit board (PCB), and a CPU 120 and a network card 130 are installed.

As shown in FIG. 9, such a board 210 includes a substrate part 211, a dehumidifying part 212, a radiating part 213, and a discharge part 214 in more detail.

The substrate part 211 forms a space in which the above-described CPU 120 and the network card 130 can be installed, and a passage that is a passage through which water condensed in the dehumidification unit 212 to be described later can be moved ( a) is formed.

The dehumidifying part 212 collects and condenses water vapor inside the case in which the board 210 is installed, and is installed on the substrate part 211 but is installed to be connected to the flow path (a). In this case, the water condensed in the dehumidifying unit 212 moves along the flow path a and is vaporized in the heat dissipation unit 213 described later.

The heat dissipation part 213 is provided with a metal material to exchange heat generated from the CPU 120 with the outside, and is installed on the substrate part 211, and is disposed under the CPU 120 to be generated from the CPU 120. Absorbs heat

The heat dissipation part 213 is installed so as to be exposed to the flow path a formed inside the substrate part 211. According to this heat dissipation part 213, the liquid water is vaporized into water vapor, which is generated in the CPU 120. Heat can be absorbed.

The discharge part 214 forms a discharge passage (o) so that the steam vaporized in the heat dissipation part 213 can be discharged to the outside of the case, and is installed on the substrate part 211 but is installed under the heat dissipation part 213 do.

According to the board 210 having the structure as described above, since moisture that may remain inside the case can be removed and heat generated from the CPU 120 can be effectively absorbed, the life of the board 210 is increased. The effect that can be made is expected.

In the above, even if all the constituent elements constituting an embodiment of the present invention are described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all the constituent elements may be selectively combined and operated in one or more.

In addition, terms such as "include", "consist of" or "have" described above mean that the corresponding component may be present unless otherwise stated, excluding other components It should not be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined, to which the present invention belongs. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

And the above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the technical field to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention.

Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: Android-based embedded board with improved real-time performance according to an embodiment of the present invention
110: board
R: Real-time kernel
NR: Non-real-time kernel
110a: insertion module
110b: elastic member
120: CPU
130: network card
200: Android-based embedded board with improved real-time performance according to another embodiment of the present invention
210: board
211: substrate portion
a: Euro
212: dehumidification unit
213: radiator
214: discharge part
o: discharge passage

Claims (5)

A board operated based on the Android operating system;
A CPU installed on the board and controlling the board;
A network card installed on the board so that the board can exchange information with an external device, and configured to correspond to an EtherCAT (Ethernet for Control Automation Technology) communication method; And
Including a case in which the board is installed inside,
The CPU,
It is prepared with ARM series CPU,
The kernel (Kernel) layer constituting the operating system,
A non-real-time kernel prepared as a Linux kernel to process non-real-time tasks, and a real-time kernel formed by implanting Xenomai into the Linux kernel and processing real-time tasks received through the EtherCAT communication method independently from the non-real-time kernel, and ,
The real-time kernel,
It has a higher priority than the NRT kernel when processing tasks,
The EtherCAT master in the above EtherCAT communication method,
It is prepared as an IgH EtherCAT master and interlocks with the network device driver through a generic driver method.
The board,
A substrate portion in which a flow path through which water can be moved is formed; a dehumidifying portion installed in the substrate portion to be connected to the flow path and collecting and condensing water vapor inside the case; and a dehumidifying portion disposed below the CPU, the flow path A heat dissipation unit installed on the substrate to be exposed to and absorbing heat generated from the CPU by vaporizing water supplied from the flow path, and a heat dissipation unit installed on the substrate unit and discharge vaporized water vapor from the heat dissipation unit to the outside of the case Android-based embedded board with improved real-time performance including an exhaust part that forms an exhaust passage so that it can be used. delete delete delete The method according to claim 1,
The board,
Android-based embedded board with improved real-time performance, characterized in that it is provided in a Mini-ITX form factor.

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