Machine Tool Simulation Research Articles

자기베어링 스테이지의 동적 거동 통합 시뮬레이션을 통한 제어 설계

The dynamic simulation of machine tools and motion control systems has been widely used for optimization, design verification, control design, etc. There are three main streams in dynamic simulation: structural dynamic analysis based onthe finite element method, dynamic motion analysis based on equations of motion, and control system analysis based on transfer functions. Generally, one of these dynamic simulation methods is chosen and employed for specific purposes. In this study, an integrated dynamic simulation is introduced, in which the structure, motion, and control dynamics are combined together. Commercially well-known software is used in the integrated dynamic simulation: ANSYS, ADAMS, and Matlab/Simulink. Using the integrated dynamic simulation, the dynamics of a magnetic bearing stage is analyzed and the causes of oscillation and noise are identified. A controller design for suppressing a flexible dynamic mode is carried out and verified through the integrated dynamic simulation.

A method for thermal performance modeling and simulation of machine tools

The development of precision machine tools requires an accurate understanding of the thermal be- haviour of the tools. Therefore, by developing highly accurate machine tool thermal behaviour simulations, it can accurately forecast the functional performance of a machine tool at the prototype design stage and provide guidance on its design and performance optimization. To improve the accuracy of the thermal simulation of machine tools, it proposed whole-machine temperature field and thermal deformation modeling and a simula- tion method for vertical machining centers. Based on the studies of thermal-structure coupling finite-element data flow and its critical conditions, it also proposed design and computational methods for obtaining the heat-source power, when various rotational speeds, the forced convection heat transfer coefficient between a rotating surface and the air, the combined heat transfer coef- ficient between a stationary surface and the air/environment, and key contact surface thermal resistances were considered. Furthermore, this paper performed finite-element simulation analysis based on the constructed whole-machine thermal model, and the temperature characteristics and heat deforma- tion mechanism/state were obtained. After comparing the simulation and experimental results, it verified the effective- ness of the finite-element simulation model and the relevant methods and confirmed that the simulation accuracy for both the temperature characteristics and the thermal defor- mation had been improved significantly, with a simulation error less than 10 %.

Physically Consistent Parameter Optimization for the Generation of Pose Independent Simulation Models Using the Example of a 6-axis Articulated Robot

In the context of shortening product life cycles, simulation of machine tools is more and more in the conflict between economic efficiency and technical requirement. Due to this both complex simulation tools and simulation methods with minimal effort are used. In the model alignment – an essential part of simulation – the highly parameterized models are adapted to the measurement data using adequate fitting algorithms from optimization theory. Thereby the pose dependence of the adapted simulation models is the result and thus multiple model alignments in the other relevant poses of the researched machine are necessary. This is associated with a high measuring expenditure, a high personal expenditure and an increasing development time of the machine.In this paper a method for the generation of pose independent simulation models by the example of a 6-axis articulated robot is presented. Basically, the model alignment is done in a way that the fitting model parameters are disturbed systematically with respect to physical sense and the resulting models have to be proved in terms of their physical plausibility. First of all, simulation models with different optimal parameter configurations related to the measured data are generated. After this, the resulting parameters are analyzed concerning their behavior in all poses and physically consistent parameter configurations of every pose are identified. Finally, the discovered configurations are used to create an exclusive parameter configuration respectively an exclusive simulation model. The pose independence of this model is postulated and the developed method is verified by the example of a 6-axis articulated robot. The implementation of the method is based on a new way of modeling mechatronic multi body dynamics using the bond graph theory. Therefore it also contains the description of the machine structure by symbolic equations of motion. This enables a transfer of the method to other machine structures without consideration of special software tools.

A STEP-compliant computer numerical control based on real-time Ethernet for circuit boardmilling

With the globalisation of manufacturing industry, extendable and networked computer numerical control systems that can support bidirectional and seamless data exchange are in urgent need. This paper presents a STEP-NC compliant controller based on Real-time Ethernet technologies, which consists of functional modules such as General Interpreter, Machining Manager, Tool Path Generation, Machine Tool Model, Simulation and Real-Time Ethernet Interface. The proposed controller is implemented for circuit board milling. In the controller, STEP-NC is utilised as the data format, as well as a part of the controller's software structure. The late binding together with object oriented polymorphism and iteration, which can accomplish general functions, is used in developing the interpreter. This, together with the Reflection mechanism, also realises the general function of creating and modifying some of the STEP data. This controller is then tested on a circuit board milling machine, with ISO 14649 files generated by a CAM module developed in association with this work, in which some AP210 entities are added to represent circuits’ geometry and translated to machining features in the STEP-NC format. Moreover, machining a single feature with multi tools is discussed and the concept of final features is adopted; all contribute to some effective milling strategies.

Sensitivity analysis and adaptive multi-point multi-moment model order reduction in MEMS design

We present a model order reduction algorithm for linear time-invariant descriptor systems of arbitrary derivative order that incorporates sensitivity analysis for network parameters in respect to design parameters. It is based on implicit moment matching via rational Krylov subspace methods with adaptive choice of expansion points and number of moments based on an error indicator. Additionally, we demonstrate how parametric reduced order models can be obtained at nearly no extra costs, such that parameter studies are extremely accelerated. The finite element model of a yaw rate sensor MEMS device has been chosen as a numerical example, but our method is also applicable to systems arising in modeling and simulation of electromagnetics, electrical circuits, machine tools, heat conduction and other phenomena.

Research on Function Simulation of Web-Based Virtual Grinding Machine Tool

The paper presents a Web-based virtual machine tool system construction method. The key technologies required to build the system were analyzed. A simulation platform is built with ASP technology, and the geometric simulation is researched by using VRML, JavaScript, and JavaApplet. The physical simulation is researched by using Matlab Web Server, The object of the virtual machine tool simulation system is ultra-high speed grinding test bench. The developed system can realize virtual assembly, CNC code identification, material removal simulation, grinding force calculation and optimization.

Development of integrated rotorcraft design and virtual manufacturing framework

PurposeThe purpose of this paper is to develop an integrated rotorcraft design and virtual manufacturing framework. The framework consists of two major sub‐frameworks which are e‐design and virtual manufacturing frameworks. This paper aims to describe the process of generating a specific framework for helicopter design and manufacturing in general, and a method for main rotor blade design.Design/methodology/approachThe e‐design process integrates a pre‐conceptual, conceptual and preliminary design phases and includes many high accuracy physics‐based analysis tools and in‐house codes. The development of analysis programs and integration of flow data are discussed under the e‐design process. The virtual manufacturing process discusses physical three‐dimensional (3D) prototypes using rapid prototyping, virtual process simulation model development using Delmia Quest, virtual machine tool simulation and process‐based cost model. Vehicle geometry is modelled parametrically in computer‐aided 3D interactive application (CATIA) V5 to enable integration between the e‐design and virtual manufacturing processes, and then saved in Enovia SmartTeam which is commercial software for product data management (PDM). Data saved in Enovia SmartTeam are used as a database for the virtual manufacturing process.FindingsThe integration framework was constructed by using Model Center software. A multi‐disciplinary design optimization loop for rotor blade considering manufacturing factors is discussed to demonstrate the robustness and efficiency of the framework.Practical implicationsThe manufacturing (practical factors) could be considered at an early stage of the rotor blades design.Originality/valueThe gap between theoretical (engineering design: aerodynamic, structural, dynamic, design, etc.) and practical aspects (manufacturing) is bridged through integrated product/process development framework. The modern concurrent engineering approach is addressed for helicopter rotor blade design throughout the case study.

Virtual Processing Research on Auto Control Valve Cylinder Mold

Especially from the perspective of geometric simulation, through the combination of CAD/CAM software Pro/e with professional numerical control machine tool simulation software Vericut, achieve the virtual processing of cylinder mold. Numerical control programs will be transferred to the virtual machine tool, producing products meet the requirements. Proving the combination of Pro/e and Vericut for the research of virtual machine technology is a possible method.

Development of Virtual Machine Tool for Simulation and Evaluation

AbstractMachine tools play an important role in manufacturing, but it is not easy to ensure efficiency and low cost, for machine tools. A machine tool simulation and evaluation system is urgently required. This paper presents an integrated machine tool simulation and evaluation system, which incorporates 3-D motion simulation and collision detection. The evaluation system incorporates post-processor and volumetric error analysis, for the evaluation of preliminary manufacturability and cutting force simulation. Using integrated virtual machine tool technologies, a variety of engineering activities in the product cycle can be performed digitally, to assess the characteristics of the real machine tool.

Machine tool simulation based on reduced order FE models

Abstract Numerical simulations of the behavior of machine tools are usually based on a finite element (FE) discretization of their mechanical structure. After linearization one obtains a second-order system of ordinary differential equations. In order to capture all necessary details the system that inevitable arises is too complex to meet the expediency requirements of real time simulation and control. In commercial FE simulation software often modal reduction is used to obtain a model of lower order which allows for faster simulation. In recent years new methods to reduce large and sparse dynamical systems emerged. This work concentrates on the reduction of certain FE systems arising in machine tool simulation with Krylov subspace methods. The main goal of this work is to discuss whether these methods are suitable for the type of application considered here. Several Krylov subspace methods for first or second-order systems were tested. Numerical examples comparing our results to modal reduction are presented.

Simulation of parallel kinematic machine tools with minimal effort

New innovative machine tool concepts like parallel kinematics require the development process to be continuously supported by simulation. Otherwise it will be impossible to exploit their full potential due to the complexity of the kinematic and dynamic behavior. Nevertheless, machine tool manufacturers often refrain from employing simulation tools because of the high effort and expenses expected for the introduction of this technology. It is against this backdrop that the paper presents a method to support the development process of parallel kinematic machine tools with a minimum of effort. An analysis of the development process identifies the machine characteristics that have to be determined for each stage. A simulation method is developed based on these results and on the requirements for a seamless integration of the simulation techniques into the different stages of the process. It is implemented and tested by the example of a parallel kinematic machine tool that has already been successfully introduced in industry.

Optimization of multi-stage closed-die forging processes by coupled simulation of the machine and the forging processes

The use of finite element analysis in the development of closed-die forging processes is widely established in industry. However, the simulated and the real workpiece dimensions differ from each other in a significant way, as the interactions between the forging process and the production machine are not adequately considered in the simulation. As a result, multi-stage dies in particular often need to undergo an experimental time-consuming optimization process on the production machine. In this paper a method is presented that allows the coupling of the forging simulation with external machine tool simulation systems and nonlinear-elastic press models in order to consider the interactions between the process and the machine, and to improve the accuracy of the forging simulation. This method of coupled simulation was integrated into a software tool and may be used for single-stage as well as for multi-stage processes in closed-die forging operations. It allows simulation-aided optimization of the dies as early as the design stage as well as individual adaptation to the particular production press well in advance of the test phase of the dies on the press.

Non-Contact Measuring Modeling and Simulation of CNC Machine Tools under High Feed Rate Condition

This article sets forth a new precision measurement method of CNC machine tools. The method incorporates the laser interferometer and the measurement principle of the double ball bar (DBB), and can measure the machine tool precision under the high feed rate condition. The generalized measurement model of three-axis has been built. Data analysis software is developed to simulate the run condition of machine tools. The repeatable experiment results proves that the method is feasible and its precision is higher than DBB`s.

Hardware-in-the-loop simulation of machine tools and manufacturing systems

Simulation methods play an important role in the design loop of sophisticated machine tools. In this paper we present a different type of simulation strategy, a method that integrates control hardware within a simulation model of the machine tool. For motion control software developers, the benefits are twofold: a simulation test bed becomes available before the machine is available, while the quality of the software migration process can be improved using automated regression tests.

A virtual machine concept for real-time simulation of machine tool dynamics

When designing CNC machine tools it is important to consider the dynamics of the control, the electrical components and the mechanical structure of the machine simultaneously. This paper describes the structure and implementation of a concept for real-time simulation of such machine tools using a water jet cutting machine as an application. The concept includes a real control system, simulation models of the dynamics of the machine and a virtual reality model for visualisation. The real-time capability of the concept, including the simulation of electrical and rather detailed mechanical component models is proofed. The validation process indicates good agreement between simulation and measurement, but suggests further studies on servo motor, connection and flexibility modelling. However, already from the initial simulation results presented in this paper it can be concluded that the influence of structural flexibility on manufacturing accuracy is of importance at desired feeding rates and accelerations. The fully automated implementation developed in this work is a promising base for dealing with this trade-off between productivity and accuracy of the manufacturing process through multidisciplinary optimisation.

Hardware-in-the-loop simulation of machine tools and manufacturing systems

Hardware-in-the-loop simulation of machine tools and manufacturing systems

“Hardware in the Loop” Simulation of Machine Tools

This paper describes a time-deterministic model for the real-time simulation of machine tools using a real CNC. The realized virtual machine tool was validated by comparing the simulated milled work piece with a machined one. The results demonstrate that despite the real-time demands an accurate representation of the machine tool's behavior can be achieved.

INTEGRATION OF REAL-TIME CONTROL SIMULATION TO A VIRTUAL MANUFACTURING ENVIRONMENT

This paper presents a new integrated approach for simulation developed to improve the accuracy of virtual manufacturing environments. While machine tool simulation and virtual manufacturing for factory simulation have been frequently used in early stage plant development, each of these technique has been researched and implemented separately. This paper focuses on the utilization of real-time simulation of machine tools or active axes in manufacturing systems and integration of this simulation capability with virtual manufacturing environments. Machine-level simulation results are generated in real-time with a real machine tool controller and are fed to a virtual manufacturing environment. To integrate these two simulation techniques, system-level software is utilized as a communication platform. This system-level software was originally developed to control and configure whole manufacturing systems. The method has been successfully implemented within a testbed with full-scale machine tools. The results demonstrate that the proposed method advances the virtual manufacturing environments toward improved accuracy of factory level simulation, reduced effort for modeling and expanded functionality of machine-level simulations.

Modeling, simulation and control of high speed machine tools using robotics formalism

This paper deals with the modeling, simulation and numerical control of high speed machine tool axes. A new way of modeling is introduced by using the description of robotic manipulators. The dynamics of rigid bodies, the elasticity of the bodies and the mechanical transmission, the dynamics and saturations of the electric actuators, the effect of the numerical control as delays and quantization are considered for the simulation. The cascade PI speed loop and P position loop controller is designed using a frequency approach and an optimization procedure taking into account the lumped model and the effects of digital control. An experimental validation on real machine tool axis is presented and compared with the simulated results.

A SHAPE AND SIZE OPTIMIZATION ALGORITHM FOR MACHINE TOOL ELEMENT DESIGN

A shape and size optimization algorithm is developed to incorporate the shape and size variables in a recently developed machine tool simulation and design methodology known as Integrated Machining Process Design Simulator (IMPDS). This shape optimization algorithm, using coordinates of master nodes, parameters of geometric equations, coordinate linking and symmetry option approaches presents a general and flexible way of controlling and optimizing the structural shape of machine tool elements. An application of the proposed shape and size optimization algorithm indicates that the shape and size parameters have significant effects on the structural characteristics and the dynamic behavior of machine tool elements.