Control Code Generation Research Articles

Fabrication of randomly distributed V grooves on the great circles of a spherical surface using ultra-precision five-axis milling

Multi-axis ultra-precision milling is a powerful technology which enables the manufacturing of various complicated curved surfaces. However, in the fabrication of an undetermined and random micro-structured surface, the conventional manufacturing mode from a given geometry model to the final surface machining is no longer applicable. Therefore, this work presents an integrative numerical control (NC) code generation method for fabricating randomly distributed V grooves on the great circles of a spherical surface firstly, in which the tool path generation is integrated into the geometry design process. The randomness of the V grooves refers to the geometric feature that the normal vectors of all the planes of the great circles are randomly generated, which are uniformly distributed towards the corresponding points on a unit sphere. Besides, the singular movements in five-axis milling of the randomly distributed V grooves on the great circles are analyzed. It is revealed that there are two distinct mechanisms of the singularity problem. One is the singular configuration of the machine tool, and the other is the discretization of the generated tool path. Subsequently, a general post-processing algorithm is contributed to solve the singularity problem, which enables the generation of NC code with error control. Furthermore, in five-axis milling of the randomly distributed V grooves on the great circles, the position error of tool virtual center can also significantly influence the machining accuracy. Therefore, a two-point calibration method is proposed to accurately determine the position of tool virtual center. Finally, a high-precision random V groove-structured sphere is machined by using the proposed NC code generation method and the tool virtual center calibration method. The maximum depth error of the V grooves is controlled less than 3.3 μm. The proposed methods in this work enable five-axis milling of high-precision random micro-structures on a spherical surface.

Formal modelling of a sheet metal smart manufacturing system by using Petri nets and first-order predicate logic

This study introduces a developed method to a smart computer-aided design/manufacturing (CAD/CAM) system, where layout design, process planning, and comprehensive computerized numerical control (CNC) code generation can be implemented to satisfy laser cutting holes, tapping, irregular and complicated profile processing, engraving, and burr back-scraping. The smart CAD/CAM(SCAM) system is developed as a commercial software product or application and firstly applied to flexible sheet metal machining center (BGL 130R). In this study, a formal modeling method involving Petri nets and first-order predicate logic is proposed to develop the smart manufacturing system. High-level Petri nets are employed to achieve the formal application architecture design of data flow for various functions, and the first-order logic used to represent the process plan is defined and deduced according to the machining methods. The developed system possesses the following characteristics: (1) a sound and complete deductive system to implement various types of trajectory planning, automatic generation, and validation of the CNC code; (2) a convenient design input environment and readiness for re-design and modification by adding specific design functions and using standard design procedures on a widely used CAD/CAM package; (3) helpful for designers in sheet metal layout designing, layout interference detection, process planning validation, preprocess manufacturing operation of CNC code generation, and autodefinition of storable file names; and (4) formal and simple in human–computer interaction, automatic and intelligent in process operations, and satisfactory in terms of the requirements of the flexible sheet metal machining center (BGL 130R).

A classification framework for automated control code generation in industrial automation

Software development for the automation of industrial facilities (e.g., oil platforms, chemical plants, power plants, etc.) involves implementing control logic, often in IEC 61131-3 programming languages. Developing safe and efficient program code is expensive and today still requires substantial manual effort. Researchers have thus proposed numerous approaches for automatic control logic generation in the last two decades, but a systematic, in-depth analysis of their capabilities and assumptions is missing. This paper proposes a novel classification framework for control logic generation approaches defining criteria derived from industry best practices. The framework is applied to compare and analyze 13 different control logic generation approaches. Prominent findings include different categories of control logic generation approaches, the challenge of dealing with iterative engineering processes, and the need for more experimental validations in larger case studies.

Distributing Sequential Control for Manufacturing Automation Systems

Recent trends in manufacturing require the use of reconfigurable equipment that facilitates rapid and cost-effective change of functionality through modular design, which supports fast integration. Intelligent devices (e.g., sensors, actuators) with integrated computation and communication capabilities enable high-level modularity, not only with the respect to hardware components but also in terms of control functionality; this can be achieved by distributing control to different network-connected devices. Thus, to enable fast and reliable system reconfigurations, in this brief, we introduce a method for distribution of control tasks and generation of control code for the devices in the control network. Our approach is based on the control interpreted Petri nets (CIPNs) formalism. We start from a CIPN capturing the centralized (overall) control system, and the mapping of input and output signals to local controllers (LCs) (i.e., smart devices) that have direct physical access to system sensors and actuators. From these, our method automatically designs distributed control tasks for LCs in the network, as well as generates control code for each LC. The applicability of the proposed method is experimentally verified on two real-world case studies.

Model for Web-Application based Configuration of Modular Production Plants with automated PLC Line Control Code Generation

The international competition leads manufacturers in high-wage countries to focus more on high-value products, which often come at the disadvantage of small batch sizes. To remain competitive, the plant engineering for should be time and cost effective. One approach to achieve this are modular production lines. In the presented contribution, a product orientated web- service for the configuration of a modular production plant investigated. The resulting model then is interpreted by a code generator to generate a PLC line control. The approach is validated with a plant of metal hybrid carbon fiber seat rests.

A Semiautomatic, Cleaning Room Grinding Method for the Metalcasting Industry

This paper presents a semi-automated grinding system for the postprocessing of metalcastings. Grinding is an important procedure in the “cleaning room” of a foundry, where the removal of gate contacts, parting line flash, surface defects, and weld-repaired areas is performed, and almost always manually. While the grinding of repetitive locations on medium to high production castings can be automated using robotics or otherwise, it is not as practical for larger castings (e.g., > 200 kg) that are typically produced in smaller production volumes. Furthermore, automation is even more challenging in that the locations of the required grinding are not a constant depending on the unique conditions and anomalies of each pouring of a component. The proposed approach is intended for a simple x−y−z positioner (gantry) device with a feedback controlled grinding head that enables automated path planning. The process begins with touch probing of the surfaces that contain the anomaly requiring grinding, and then the system automatically handles the path planning and force control to remove the anomaly. A layer-based algorithm for path planning employs a search-and-destroy technique where the surrounding geometry is interpolated across the grind-requiring surface patch. In this manner, each unique condition of the casting surface after initial torch or saw cutting can be handled cost effectively without the need for human shaping and the egregious ergonomic problems associated. Implementation of the proposed grinding control is prototyped at a lab scale to demonstrate the feasibility and versatility of this strategy. The average error for the prototype was on the order of 0.007 in (0.2 mm) with a flatness of the ground surface within 0.035 in (0.9 mm), which is within the cleaning room grinding requirements, as per ISO and ASTM dimensional and surface tolerance requirements. A significant contribution of the work is the layer-based algorithm that allows an effective automation of the process planning for grinding, avoiding robot programming or numerical control code generation altogether. This is a key to addressing the largely unknown and unpredictable conditions of, for example, the riser contact surface removal area on a metalcasting.

Automation of tool path generation in multi-process micromachine tool for micromachining of prismatic and rotational parts

ABSTRACTComputer numerical control (CNC) code generation is an inimitable activity of a Computer-aided manufacturing (CAM) system. Tool path formulation is considered as a machine-dependent activity, and expertise is essential to make attuned for a specific micromachine tool. This paper describes research for retrofitting of a multi-process micromachine tool for automatic CNC code generation for 2.5D micromachining. Micro turning, micro drilling and micro end milling processes are all considered. The proposed system comprises of three main elements: (i) part feature extraction through an extensible mark-up language (XML) schema, (ii) manufacturing logic formulation and CNC code generation by means of mathematical logic and (iii) online integration. XML-based feature extraction ensures trouble-free integration with the decision-making system. Automation of CNC code generation eliminates the need of human expertise, avoids compatibility issues and minimises program creation time. The developed system integrated with the micromachine tool through communication interface for real-time micromachining. The proposed system is intended for 2.5D machining of miniature and micro parts with external step, hole and slot features. The developed system performance has been validated through case study implementations.

Design and Implementation of Cascade LQR Controller for Stabilization of Two-Wheeled Robot

Abstract In this paper the developed two-wheeled robot and cascade LQR controller, Kalman filters, PI and PID controllers are presented. The cascade LQR controller stabilizes the two-wheeled robot in upright position. The PID controller ensures good tracking of wheel position reference and the PI controller steers two-wheeled robot rotation around the vertical axis. A software in MATLAB®/Simulink environment intended for design and generation of control code which is embedded in a Texas Instruments Digital Signal Controller is developed. Simulation and experimental results of system performance are given that confirm the efficiency of the control system developed.

Supervisory control theory applied to swarm robotics

Currently, the control software of swarm robotics systems is created by ad hoc development. This makes it hard to deploy these systems in real-world scenarios. In particular, it is difficult to maintain, analyse, or verify the systems. Formal methods can contribute to overcome these problems. However, they usually do not guarantee that the implementation matches the specification, because the system’s control code is typically generated manually. Also, there is cultural resistance to apply formal methods; they may be perceived as an additional step that does not add value to the final product. To address these problems, we propose supervisory control theory for the domain of swarm robotics. The advantages of supervisory control theory, and its associated tools, are a reduction in the amount of ad hoc development, the automatic generation of control code from modelled specifications, proofs of properties over generated control code, and the reusability of formally designed controllers between different robotic platforms. These advantages are demonstrated in four case studies using the e-puck and Kilobot robot platforms. Experiments with up to 600 physical robots are reported, which show that supervisory control theory can be used to formally develop state-of-the-art solutions to a range of problems in swarm robotics.

Formal representation of GRAFCET to automatically generate control code

Within the engineering of control code, model-based approaches become more and more important. Basically GRAFCET serves as a suitable modeling language but lacks an exhaustive formal representation of its structure and dynamic behavior since current approaches only consider subclasses of GRAFCET. Within this article the authors depict a systematic approach for an exhaustive formal model of GRAFCET, specifically by taking enclosing steps, forcing orders and time constraints into account. Based on this formal model of GRAFCET a method together with a tool framework are presented allowing for the automatic generation of control code.

The Control System for Metal Forming Based on Computer Aided Design

This paper presents the design of control system of direct metal deposition forming software. The system which is designed by VC++ software employs the ideas of object-oriented and data stream. The metal parts are abstracted into objects and classes to realize the reusability and scalability. The software control system has realized from the machine initialization, digital control code generation, forming process control, process parameter management module. The control system can improve the forming quality and achieve the best forming process control, saving the metal parts of the development time and cost of development.

Autonomic Wireless Sensor Networks: A Systematic Literature Review

Autonomic computing (AC) is a promising approach to meet basic requirements in the design of wireless sensor networks (WSNs), and its principles can be applied to efficiently manage nodes operation and optimize network resources. Middleware for WSNs supports the implementation and basic operation of such networks. In this systematic literature review (SLR) we aim to provide an overview of existing WSN middleware systems that address autonomic properties. The main goal is to identify which development approaches of AC are used for designing WSN middleware system, which allow the self-management of WSN. Another goal is finding out which interactions and behavior can be automated in WSN components. We drew the following main conclusions from the SLR results: (i) the selected studies address WSN concerns according to the self-*properties of AC, namely, self-configuration, self-healing, self-optimization, and self-protection; (ii) the selected studies use different approaches for managing the dynamic behavior of middleware systems for WSN, such as policy-based reasoning, context-based reasoning, feedback control loops, mobile agents, model transformations, and code generation. Finally, we identified a lack of comprehensive system architecture designs that support the autonomy of sensor networking.

Automatic Feature Extraction and CNC Code Generation in a CAPP System for Micromachining

Feature extraction from a part model and Computer Numerical Control (CNC) code generation for machine tool control are the two extreme activities of a typical CAPP system. The present work discusses about a new methodology for automatic part feature extraction and CNC code generation for the invention of micro features in tool based micromachining processes. It has two main components; the first one deals with Extensible Mark-up Language (XML) based feature extraction from feature based model and interactive feature recognition. The second one deals with autonomous CNC code generation based on manufacturing features using various mathematical logic. Feature extraction through XML files avoids complex feature extraction process and automation of CNC code generation avoids human expertise and compatibility issues. The developed system integrated with micromachine tool through RS 232 communication interface. Hence for the given micro features, CNC code generation take place automatically and transferred to the micromachine tool in online with minimal user interface. The application of the proposed system verified with a case study. The developed system is limited to the parts having micro external step and drill features. Incorporation of more micro features, consideration of various other process planning activities and its part program generation ensures a complete CAPP system for micromachining.

Robot control code generation by task demonstration in a dynamic environment

Within mobile robotics, one of the most dominant relationships to consider when implementing robot control code is the one between the robot’s sensors and its motors. When implementing such a relationship, efficiency and reliability are of crucial importance. The latter aspects often prove challenging due to the complex interaction between a robot and the environment in which it exists, frequently resulting in a time consuming iterative process where control code is redeveloped and tested many times before obtaining an optimal controller. In this paper, we address this challenge by implementing an alternative approach to control code generation, which first identifies the desired robot behaviour and represents the sensor-motor task algorithmically through system identification using the NARMAX modelling methodology. The control code is generated by task demonstration, where the sensory perception and velocities are logged and the relationship that exists between them is then modelled using system identification. This approach produces transparent control code through non-linear polynomial equations that can be mathematically analysed to obtain formal statements regarding specific inputs/outputs. We demonstrate this approach to control code generation and analyse its performance in dynamic environments.

고정폐색 열차제어시스템 속도제어코드 설계에 관한 연구

Kyung-Bu High Speed Railway is operated in train control system(tcs) of fixed block operated in a way of dividing track circuits into several blocks in accordance with operation circumstances such as rolling stocks, grade, curves and facilities. The TCS of fixed block system refers to a continuous train control system, which transfers operational information such as entry and exit speed, distance-to-go, and deceleration etc. into on-board train control equipment on the basis of block occupancy of a preceding train. It guarantees a safe operation of trains by giving an emergency braking order, in case that a train exceeds an entry and exit speed of a corresponding block. In this paper, we analyze the speed control code deducing in accordance with maximum operation speed and characteristics of rolling stocks by analyzing principles of generation of speed control code allocated in blocks for safe operation, then train operational efficiency was analyzed by means of analysis of operation headway in accordance with the deduced speed control code. This study will be used to design in case of getting an increase in speed for existing high speed line or new high speed line TCS.

Specification and implementation of a Hierarchical and Modular meta-model for manufacturing system Control

AbstractThe paper presents a research work proposing the definition of a new approach to design and test the control logics for manufacturing systems. Starting from the Object-Oriented paradigm, a modular and hierarchical meta-model for the control specification and design is proposed. The core of the new approach is the control module, a basic standard reusable functional entity which permits to design and implement a portion of larger control logics focusing only on the behaviour of single component. The interface standardization and the hidden information concepts allow facilitating the overall control architecture design, the testing of the developed logics, a high level of reuse of the pre-designed control modules and finally an automatic control code generation. The paper describes an application of the proposed methodology for a real application, the machine SPI, providing an overview on the GUI editor and on the control code generator for a commercial soft PLC.

Model-Driven Flow for Assistive Home Automation System Design

AbstractPeople with disabilities sometimes have considerable difficulties, or even physical incapacities, performing daily tasks independently. Many research works have introduced home automation as a useful way to overcome these activity limitations. However, very few of these accomplishments have focused on the design of intelligent systems which would allow nonexperts to model and to adapt a home automation environment for the disabled. This design work is currently restricted to technicians, rather than occupational therapists or others who are able to best understand the needs of those with mobility or cognitive impairments. To take up these challenges, this paper proposes a design flow including a component approach for modeling system architecture and a range of services to meet the needs of both developers and users. Based on model driven engineering, it automates the control code generation for home automation systems.

Rapid Control Prototyping Platform for the Design of Control Systems for Automotive Electromechanical Actuators

This article introduces and discusses the development of a low-cost Rapid Control Prototyping Platform (RCPP). The aim of RCPP is to automate design of control algorithm of electromechanical actuators and simultaneous implementation it into a target microprocessor. The RCPP is stand-alone system containing software tools and electronic hardware in order to provide all development steps from system identification, model-based control design and code generation up to hardware implementation. The system can be used for development of a torque, speed or position controller for low power electromechanical actuators especially in the area of automotive application. The hardware of the platform is based on a 16-bit microcontroller and includes essential power semiconductor switches, sensors and communication interfaces. The presented RCPP system supports Real-Time-Work interface of MATLAB/Simulink and Calibration Protocol for CAN-Bus communication.

Automation of Process Planning for Boring of Turned Components With Arbitrary Internal Geometry From a Semi-Finished Stock

This paper describes a novel method for automated process planning for boring of turned components with arbitrary internal geometry from a semi-finished stock. Earlier work has been reported on process planning for boring of components with monotonic internal geometry made from bar stock. This paper addresses the more general problem of process planning of parts with nonmonotonic internal geometry from arbitrary given the initial geometry, i.e., from a casting or from a semi-finished stock. With the algorithms developed, we are able to achieve full automation of all aspects of the process plan, including operations sequencing, parameter selection, numerical control (NC) code generation, etc. Thus, it becomes possible to go from design to NC code in a fully automated fashion. In the present work we focus on a tightly defined part family, which results in very simple but robust automation algorithms. This is in contrast to much of the reported work on automated process planning, which generally targets broad part families, leading to complex algorithms that fall short of complete design-to-NC automation.

A Contribution of Graph Grammar Techniques to the Specification, Verification and Certification of Code Generation Tools

The software and hardware quality of safety-critical embedded systems in avionics and the automotive sector is currently ensured by extensive assurance procedures (e.g. certification). In this application area the use of models in the development of embedded systems has become increasingly important. These models are used from the early development stages through to implementation to verify desired software behaviour (model-based development). New approaches allow automatic generation of compact controller code directly from the software model via so-called code generators. However, certifying a code generator (as well as a compiler) premises a complete and comprehensible description of the translation process from the model to the generated code. This paper proposes the use of different graph grammar techniques as a basis for the specification and verification of the transformation process as a contribution to the certification of code generation tools.