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Национальная ассоциация ученых (НАУ) # 77, 2022
ТЕХНИЧЕСКИЕ НАУКИ
DEVELOPMENT OF PRINCIPLES FOR CONSTRUCTION OF A MODERN CONTROL SYSTEM
FOR A MANIPULATION ROBOT.
Aliyeva Y.N., Valiyeva, A.I.
Azerbaijan State Oil and Industry University
РАЗРАБОТКА ПРИНЦИПОВ ПОСТРОЕНИЯ СОВРЕМЕННОЙ СИСТЕМЫ УПРАВЛЕНИЯ
МАНИПУЛЯЦИОННЫМ РОБОТОМ
Алиева Е.Н., Валиева А.И.
Ат^ллск
Of the above approaches to the creation of a modern MR CS that meets the performance and functionality requirements, the option using a CD as a control unit and a PC to create a terminal device allows the most efficient organization of the MR CS hardware and software structure. The proposed structure of the system and application software and the approach to the implementation of the task priority system are the basis for building a MR control system with wide functional and technical capabilities that meets the high requirements of contour-positional movement imposed by modern industry.
АННОТАЦИЯ
Из рассмотренных выше подходов к созданию современной СУ МР, соответствующей требованиям производительности и функциональности, вариант с использованием КД в качестве блока управления и ПК для создания терминального устройства позволяет наиболее эффективно организовать структуру аппаратных и программных средств СУ МР. Предложенная структура системного и прикладного ПО и подход к реализации системы приоритетов выполняемых задач являются базой для построения системы управления МР с широкими функционально-техническими возможностями, отвечающей высоким требованиям контурно-позиционного движения, предъявляемых современной промышленностью.
Key words: manipulator, architecture, component, electricdrive, kinematics, operator.
Ключевые слова: манипулятор, архитектурa, компонент, электропривод, кинемати^, оператор.
In order for the control system to meet the requirements of modern production, it must be adaptable for use in technological operations using various types of manipulators and peripheral equipment. To ensure this, the development of MR CS should be based on the principles of modularity and open architecture. The principle of modularity lies in the possibility of completing the final control system with a set of components that are most suitable for the task. The main components presented in (Fig. 1.) are modules, the composition and implementation of which can be determined by a specific task performed by the MR. The principle of open architecture consists in the possibility of configuring and creating individual CS components by the end user, using open data exchange protocols and providing access to software modules for developing custom programs and algorithms. The
specific implementation of the CS using these principles depends, first of all, on the hardware architecture and its underlying implementation. The main components of the hardware architecture of a modern MR control system (Fig. 1.) are the following:
1. Control unit (CU);
2. Terminal device (TD) user interface;
3. Power modules;
4. Peripheral equipment.
The control unit is the main component responsible for performing displacement calculations, monitoring the state of the system as a whole, its individual components and peripheral equipment, and executing user and system programs. CU includes means of interaction between individual components of the control system.
Figure.1. Hardware architecture of CS MR
The task of the terminal device is to ensure the interaction of the operator with the control system. To do this, it must have effective means of input/output of information. The operator console implements the functions of exchanging information with the control system, turning the system on / off, starting and executing user programs, selecting and configuring the modes of operation of the MR, signaling its status. In addition to system tasks, the operator's console must ensure the interaction of the operator with the TS software. In particular, it must have the means to enter control programs, switch software operation modes, and interact with software components. An important element of a modern MR control system, which largely determines its main quality indicators, is an electric drive. The electric drive control system of a modern MR must have a digital implementation. Without fulfilling this condition, it is impossible to ensure high rates of dynamics and movement accuracy. An effective tool for solving the problem of controlling an electric drive is its functional and physical division into two components: a power module (SM) and a software-
implemented control algorithm. Such a solution will allow the most simple and accurate synchronization of the control of the MR axes, access to state variables in real time, and dynamically change the structure and parameters of the controllers.
When performing a number of technological operations, the MR CS may face additional tasks related to the need to control peripheral devices. Such devices may include various sensors, meters and sensing tools used in the creation of advanced system and control programs. Such tasks include, for example, surface treatment with a given force of the working body or its positioning according to the readings of the vision system. The current approaches to the creation of the CS hardware base are based on the use of two main classes of devices: industrial computers (PC) and motion controllers (CD). [4, 5, 6]. The following options can be distinguished (Fig. 2.).
When using a PC, it is possible to create an easily portable system that can be implemented on a wide range of compatible devices.
Figure. 2. ALTERNATIVE ARCHITECTURES OF CONTROL SYSTEM OF MR.
The main disadvantage of this approach is the need to create the entire CS within a single device, which requires the use of a real-time operating system in which the CS components will work as separate tasks synchronized by system tools. This approach does not allow separating control and interface tasks, which increases the likelihood of hardware or software errors.
The main advantage of using multiple PCs is the ability to share tasks between them. The first PC, on which the CU is implemented, solves the problems of "real time" control, and the second PC implements the functions of the terminal device. Interaction between computers is provided on the basis of various industrial protocols.
The disadvantage of this approach is the redundancy and duplication of individual components. Such a solution turns out to be inefficient in terms of the resources used.
The other two approaches are to use a dedicated motion controller as the underlying architecture.
The use of one CD requires the implementation of both control and interface components on it. The main problem in this case is that the creation of a full-fledged user interface requires significant processing by the developer of the internal CD software to obtain the required functionality. In addition, as in the case of
using one PC, it becomes necessary to implement several CS components on one device, which can lead to instability of its operation.
To solve these problems, CD can be used in combination with a terminal device that provides control of its operation and user interface. Any device or system that provides the necessary capabilities to create a user interface can be used as a terminal. The easiest solution in this case would be to use a PC. .Unlike the previous approaches, in this case, the use of a specialized OS on a PC is not required, since the processes performed in real time are implemented in the motion controller. At the same time, the functions of the PC and CD are not duplicated, since each of them performs separate tasks. For interaction between them, you can use an industrial data interface such as EtherCAT, ModBus, PROFINET, Ethernet/IP. [7].
Of the above approaches to the creation of a modern MR CS that meets the requirements for performance and functionality, the option using a CD as a control unit and a PC to create a terminal device allows the most efficient organization of the MR CS structure. In the structure of the software (Fig. 3.) it is necessary to distinguish two classes: software for design documentation and software for technical specifications.
Figure. 3. Structure of software design documentation
The CD software includes elements designed to ensure the operation of the control unit and interaction with the hardware of the MR control system. It includes components that provide the following tasks:
1. Hardware support;
2. Electric drive control;
3. Planning and calculation of the trajectory of movement;
4. Monitoring the state of the system;
5. Execution of system programs;
6. Execution of user control programs;
7. Interaction with the terminal device. Hardware support refers to components designed
to solve such problems as polling various sensors, organizing the operation of data transfer interfaces, polling the state of the MR and other elements of the control system. This software component also includes the synchronization of processes running on CD. Control electric drive includes polling of feedback channels, algorithms of coordinate transformations,
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calculation of regulator parameters, generation of control signals, switching of power switches.
Engine control algorithms are implemented directly in the CD. In addition to control, they should allow obtaining information about the state variables of the motors (current, torque, speed, position, positioning error). They can be used to create complex control algorithms and monitor the current state of the MR.
Due to the fact that kinematic and dynamic constraints have a significant impact on the operation of the MR, it may be necessary to create an adaptive control system to ensure the required characteristics. First of all, this applies to elastic systems, as well as systems in which the influence of nonlinear elements, such as gaps and dry friction, is significant. To control them, more complex types of regulators are required [8].
The set of tools for planning and calculating the trajectory of motion includes such components as a trajectory planner (PT), programs for calculating direct and inverse problems of kinematics, and a system for processing control programs [9].
The task of the trajectory planner is to calculate the main types of trajectories used in the work of the MR: linear, circular, spline. For their implementation, appropriate interpolators are required that interact with the programs for calculating the MR kinematics.
The use of kinematics calculation programs is necessary to transfer the given movements from the coordinate system used in the control program to the coordinate system used in the manipulator and vice versa. Due to the fact that a number of complex spatial transformations are required for multi-link manipulators, computational algorithms must be optimized in terms of speed.
The monitoring tools for the system state include such components as a watchdog timer, means for monitoring the state of system emergency sensors, levels of physical quantities and other tools that allow you to determine operability of the control system and take measures to prevent and eliminate malfunctions.
Maintaining the MR control system in working condition is the task of system programs executed in the CD. They are designed to update various data, monitor the characteristics of the control system and synchronize processes in user programs.
The control program processing system provides analysis of the UE transmitted by the user and its translation into a system of CD commands. The set of tools used in writing the UE should include commands for controlling motion, transforming coordinates between CSs, and interacting with peripheral equipment.
The means of interaction with the terminal device are designed to exchange data and control information with the user. These include various buffers for transmitting information, interface tools with system state variables. First of all, you should decide on the main I / O interface.
Due to the fact that most proprietary protocols are more or less closed, the main one should be chosen based on an open standard, such as Ethernet [1, 2, 3] in industrial design (Profinet, EtherCAT, EtherNet/IP ).
Based on the foregoing, it can be concluded that a modern MR control system should be built on the basis of the principles of modularity and openness using hardware solutions that allow real-time implementation, as well as provide a set of control algorithms that provide the ability to control the manipulator in complex technological tasks.
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