Learn about the control system/software development environment/communication bus of industrial robots

1. Hardware structure of industrial robot control system

The controller is the core of the robot system, and foreign companies have imposed a strict blockade on my country. In recent years, with the development of microelectronics technology, the performance of microprocessors has become higher and higher, while the price has become cheaper and cheaper. Currently, 32-bit microprocessors with a price of 1-2 US dollars have appeared on the market. Cost-effective microprocessors have brought new development opportunities for robot controllers, making it possible to develop low-cost, high-performance robot controllers. In order to ensure that the system has sufficient computing and storage capabilities, robot controllers are currently mostly composed of chips with strong computing power, such as the ARM series, DSP series, POWERPC series, and Intel series. In addition, since the existing general-purpose chips cannot fully meet the requirements of some robot systems in terms of price, performance, integration, and interfaces in terms of functions and performance, this has created a demand for SoC (System on Chip) technology in robot systems. Integrating specific processors with the required interfaces can simplify the design of system peripheral circuits, reduce system size, and reduce costs. For example, Actel integrates the processor core of NEOS or ARM7 on its FPGA products to form a complete SoC system. In terms of robot motion controllers, the research is mainly concentrated in the United States and Japan, and there are mature products, such as the American DELTATAU company, Japan Pengli Co., Ltd., etc. Its motion controller is based on DSP technology and adopts an open structure based on PC.

2. Industrial robot control system architecture

In terms of controller architecture, the research focuses on the functional division and the specification of information exchange between functions. In the research of open controller architecture, there are two basic structures. One is the structure based on hardware hierarchy division. This type of structure is relatively simple. In Japan, the architecture is divided based on hardware. For example, Mitsubishi Heavy Industries, Ltd. divides the structure of its PA210 portable general intelligent arm robot into five layers. The other is the structure based on functional division, which considers both hardware and software. It is the direction of research and development of robot controller architecture.

3. Control the software development environment

In terms of robot software development environment, most industrial robot companies have their own independent development environment and independent robot programming language, such as Japan's Motoman, Germany's KUKA, the United States' Adept, Sweden's ABB, etc. Many universities have done a lot of research on the robot development environment (Robot Development Environment), providing a lot of open source code, which can be integrated and controlled under some robot hardware structures. Many related experiments have been carried out in laboratory environments. The existing robot system development environments at home and abroad include TeamBots, v.2.0e, ARIA, v.2.4.1, Player/Stage, v.1.6.5.1.6.2, Pyro.v.4.6.0, CARMEN.v.1.1.1, MissionLab.v.6.0, ADE.V.1.0beta, Miro.v.CVS-March17.2006, MARIE.V.0.4.0, FlowDesigner.v.0.9.0, RobotFlow.v.0.2.6, etc. From the perspective of the development of the robot industry, there are two demands for robot software development environments. On the one hand, there is demand from robot end users, who not only use robots, but also hope to give robots more functions through programming. This programming is often implemented using visual programming languages, such as the graphical programming environment of Lego MindStormsNXT and the visual programming environment provided by Microsoft RoboticsStudio.

4. Robot-specific operating system

(1) VxWorks. The VxWorks operating system is an embedded real-time operating system (RTOS) designed and developed by Wind River in the United States in 1983. It is a key component of the Tornado embedded development environment. VxWorks has a scalable microkernel structure, efficient task management, flexible inter-task communication, microsecond-level interrupt processing, support for POSIX1003.1b real-time extension standard, support for multiple physical media and standard, complete TCP/IP network protocols, etc.

(2) Windows CE: Windows CE has good compatibility with the Windows series, which is undoubtedly a major advantage in the promotion of Windows CE. Windows CE provides a feature-rich operating system platform for building dynamic applications and services for handheld devices and wireless devices. It can run on a variety of processor architectures and is generally suitable for devices that have certain restrictions on memory usage.

(3) Embedded Linux, because its source code is open, people can modify it at will to meet their own applications. Most of them comply with GPL, are open source and free. They can be slightly modified and applied to the user's own system. There is a large group of developers, and no specialized talents are needed, as long as they know Unix/Linux and C language. The number of supported hardware is huge. There is no essential difference between embedded Linux and ordinary Linux, and embedded Linux supports almost all hardware used on PCs. In addition, the source code of the drivers for various hardware is available, which greatly facilitates users to write drivers for their own proprietary hardware.

(4) μC/OS-Ⅱ, μC/OS-Ⅱ is a well-known real-time kernel with open source code. It is designed for embedded applications and can be used for 8-bit, 16-bit and 32-bit microcontrollers or digital signal processors (DSPs). Its main features are open source code, good portability, curability, scalability, preemptive kernel, determinism, etc.

(5) DSP/BIOS. DSP/BIOS is a real-time multitasking operating system kernel that can be customized for the TMS320C6000TM, TMS320C5000TM and TMS320C28xTM series DSP platforms. It is one of the components of TI's CodeComposerStudioTM development tools. DSP/BIOS mainly consists of three parts: multi-threaded real-time kernel; real-time analysis tools; chip support library. Using the real-time operating system development program, you can quickly and easily develop complex DSP programs.

5. Robot servo communication bus technology

At present, there is no dedicated servo communication bus for robot systems in the world. In actual application, some commonly used buses, such as Ethernet, CAN, 1394, SERCOS, USB, RS-485, etc., are usually used in robot systems according to system requirements. Most of the current communication control buses can be classified into two categories, namely serial bus technology based on RS-485 and line driver technology and high-speed serial bus technology based on real-time industrial Ethernet.