522 research outputs found
Design & Implementation of Motion Controller for Industrial Paper Cutting Machine
In order to solve a speed control, Speed measurement & synchronization problem, an effective motion controller is design & develop for paper cutting machine of papermaking plant. PID control algorithm was proposed to solve the problem in this paper. The speed closed-loop control was realized after studying & comparing different control algorithm. According to comparison of industrial application results, the applied control strategy to develop a motion controller truly guide, control & can accurately restrain the load disturbance and improve the control effect of synchronization for the cutter speed. This System proves how it can be a low cost solution in the production practice
Study on control strategy of the rotary synchronous fixed-length cutting system
According to the characteristics of rotating synchronous fixed-length cutting system and the principle of vector coordinate transformation, it respectively analyzes the mathematical model of three loops which are the position loop, speed loop and current loop of the servo fixed-length cutting system in this paper. In view of the different working conditions of the system and its nonlinear problem, it puts forward that the function of the speed loop is realized by the parameter adaptive fuzzy algorithm; the function of the position loop using is realized by feed forward proportional control algorithm; the function of the current loop is realized by the conventional PI control algorithm. It uses MATLAB to make simulation and verification, the results show that the combined control algorithm can make that the fixed-length cutting system has characteristics of fast speed, high precision and strong robustness properties
Novel control of a high performance rotary wood planing machine
Rotary planing, and moulding, machining operations have been employed within the
woodworking industry for a number of years. Due to the rotational nature of the machining
process, cuttermarks, in the form of waves, are created on the machined timber surface. It is
the nature of these cuttermarks that determine the surface quality of the machined timber. It
has been established that cutting tool inaccuracies and vibrations are a prime factor in the
form of the cuttermarks on the timber surface. A principal aim of this thesis is to create a
control architecture that is suitable for the adaptive operation of a wood planing machine in
order to improve the surface quality of the machined timber.
In order to improve the surface quality, a thorough understanding of the principals of wood
planing is required. These principals are stated within this thesis and the ability to manipulate
the rotary wood planing process, in order to achieve a higher surface quality, is shown. An
existing test rig facility is utilised within this thesis, however upgrades to facilitate higher
cutting and feed speeds, as well as possible future implementations such as extended cutting
regimes, the test rig has been modified and enlarged. This test rig allows for the dynamic
positioning of the centre of rotation of the cutterhead during a cutting operation through the
use of piezo electric actuators, with a displacement range of ±15μm.
A new controller for the system has been generated. Within this controller are a number of
tuneable parameters. It was found that these parameters were dependant on a high number
external factors, such as operating speeds and run‐out of the cutting knives. A novel approach
to the generation of these parameters has been developed and implemented within the
overall system.
Both cutterhead inaccuracies and vibrations can be overcome, to some degree, by the vertical
displacement of the cutterhead. However a crucial information element is not known, the
particular displacement profile. Therefore a novel approach, consisting of a subtle change to
the displacement profile and then a pattern matching approach, has been implemented onto
the test rig.
Within the pattern matching approach the surface profiles are simplified to a basic form. This
basic form allows for a much simplified approach to the pattern matching whilst producing a
result suitable for the subtle change approach. In order to compress the data levels a Principal
Component Analysis was performed on the measured surface data. Patterns were found to be
present in the resultant data matrix and so investigations into defect classification techniques
have been carried out using both K‐Nearest Neighbour techniques and Neural Networks.
The application of these novel approaches has yielded a higher system performance, for no
additional cost to the mechanical components of the wood planing machine, both in terms of
wood throughput and machined timber surface quality
On the investigation of the energy efficiency using PID and fuzzy logic controllers in a marble machine
Energy consumption is the main cost item in the cutting machines with diamond segmented circular sawblade. Therefore, there are many benefits of taking measures for reducing the energy consumption. The aim of presented experimental study is to develop control methods to reduce energy consumption in marble cutting process. In the study, cutting experiments were performed with a fully computer controlled test rig for three natural rocks (Burdur beige and Usak green marbles and Afyon travertine). The experiments were carried out on two modes (manual and automatic). While travel speed is kept fixed in manual mode as usual in industry, it is controlled by a controller embedded closed control loop during the cutting process in automatic mode. Other machine parameters, such as sawblade rotation speed, cutting depth and flowing speed of cooling water, are kept fixed in all experiments. In designed closed control loop, PID and FL controllers widely used in industry were used to control travel speed. Obtained results show that if the travel speed is controlled during cutting process, energy saving can be ensured by of controllers for the three rocks
Robust, reliable and applicable tool wear monitoring and prognostic : approach based on an Improved-Extreme Learning Machine.
International audienceAlthough efforts in this field are significant around the world, real prognostics systems are still scarce in industry. Indeed, it is hard to provide efficient approaches that are able to handle with the inherent uncertainty of prognostics and nobody is able to a priori ensure that an accurate prognostic model can be built. As for an example of remaining problems, consider datadriven prognostics approaches: how to ensure that a model will be able to face with inputs variation with respect to those ones that have been learned, how to ensure that a learned-model will face with unknown data, how to ensure convergence of algorithms, etc. In other words, robustness, reliability and applicability of a prognostic approach are still open areas. Following that, the aim of this paper is to address these challenges by proposing a new neural network (structure and algorithm) that enhances reliability of RUL estimates while improving applicability of the approach. Robustness, reliability and applicability aspects are first discussed and defined according to literature. On this basis, a new connexionist system is proposed for prognostics: the Improved-Extreme Learning machine (Imp-ELM). This neural network, based on complex activation functions, enables to reduce the influence of human choices and initial parameterization, while improving accuracy of estimates and speeding the learning phase. The whole proposition is illustrated by performing tests on a real industrial case of cutting tools from a Computer Numerical Control (CNC) machine. This is achieved by predicting tool condition (wear) in terms of remaining cuts successfully made. Thorough comparisons with adaptive neuro fuzzy inference system (ANFIS) and existing ELM algorithm are also given. Results show improved robustness, reliability and applicability performances
Motion control and synchronisation of multi-axis drive systems
Motion control and synchronisation of multi-axis drive system
Dynamic Modeling of a Belt Driven Electromechanical XY Plotter Cutter
Current industrial XY plotter cutters that use a belt driven gantry for the X motion and media feed for the Y motion sometimes have performance issues in cutting out high quality shapes. Mathematical models for these plotter cutters are not publicly available and thus the parameters critical to cut quality are not well understood. This thesis develops a dynamic, electromechanical model for the gantry arm and media feed using first principles and a non-linear friction model. These models are independently simulated and experimentally verified. In order to verify the effectiveness of the individual models, they are combined with a control system and trajectory generation algorithm. A rectangle, star and oval are simulated with the combined system using both a detuned and tuned controller and compared to experimental results. The effectiveness of the model is demonstrated with good agreement between theoretical and experimental results for both controllers. The resulting model can be used to improve and optimize the performance of XY plotter cutters
Investigation into vibration assisted micro milling: theory, modelling and applications
PhD ThesisPrecision micro components are increasingly in demand for various engineering industries,
such as biomedical engineering, MEMS, electro-optics, aerospace and communications. The
proposed requirements of these components are not only in high accuracy, but also in good
surface performance, such as drag reduction, wear resistance and noise reduction, which has
become one of the main bottlenecks in the development of these industries. However,
processing these difficult-to-machine materials efficiently and economically is always a
challenging task, which stimulates the development and subsequent application of vibration
assisted machining (VAM) over the past few decades. Vibration assisted machining employs
additional external energy sources to generate high frequency vibration in the conventional
machining process, changing the machining (cutting) mechanism, thus reducing cutting force
and cutting heat and improving machining quality. The current awareness on VAM technology
is incomplete and effective implementation of the VAM process depends on a wide range of
technical issues, including vibration device design and setup, process parameters optimization
and performance evaluation. In this research, a 2D non-resonant vibration assisted system is
developed and evaluated. Cutting mechanism and relevant applications, such as functional
surface generation and microfluidic chips manufacturing is studies through both experimental
and finite element analysis (FEA) method.
A new two-dimensional piezoelectric actuator driven vibration stage is proposed and
prototyped. A double parallel four-bar linkage structure with double layer flexible hinges is
designed to guide the motion and reduce the displacement coupling effect between the two
directions. The compliance modelling and dynamic analysis are carried out based on the matrix
method and lagrangian principle, and the results are verified by finite element analysis. A
closed loop control system is developed and proposed based on LabVIEW program consisting
of data acquisition (DAQ) devices and capacitive sensors. Machining experiments have been
carried out to evaluate the performance of the vibration stage and the results show a good
agreement with the tool tip trajectory simulation results, which demonstrates the feasibility and
effectiveness of the vibration stage for vibration assisted micro milling.
The textured surface generation mechanism is investigated through both modelling and
experimental methods. A surface generation model based on homogenous matrices
transformation is proposed by considering micro cutter geometry and kinematics of vibration
assisted milling. On this basis, series of simulations are performed to provide insights into the
effects of various vibration parameters (frequency, amplitude and phase difference) on the
generation mechanism of typical textured surfaces in 1D and 2D vibration-assisted micro
milling. Furthermore, the wettability tests are performed on the machined surfaces with various
surface texture topographies. A new contact model, which considers both liquid infiltration
effects and air trapped in the microstructure, is proposed for predicting the wettability of the
fish scales surface texture. The following surface textures are used for T-shaped and Y-shaped
microchannels manufacturing to achieve liquid one-way flow and micro mixer applications,
respectively. The liquid flow experiments have been carried out and the results indicate that
liquid flow can be controlled effectively in the proposed microchannels at proper inlet flow
rates.
Burr formation and tool wear suppression mechanisms are studied by using both finite element
simulation and experiment methods. A finite element model of vibration assisted micro milling
using ABAQUS is developed based on the Johnson-Cook material and damage models. The
tool-workpiece separation conditions are studied by considering the tool tip trajectories. The
machining experiments are carried out on Ti-6Al-4V with coated micro milling tool (fine-grain
tungsten carbides substrate with ZrO2-BaCrO4 (ZB) coating) under different vibration
frequencies (high, medium and low) and cutting states (tool-workpiece separation or nonseparation). The results show that tool wear can be reduced effectively in vibration assisted
micro milling due to different wear suppression mechanisms. The relationship between tool
wear and cutting performance is studied, and the results indicate that besides tool wear
reduction, better surface finish, lower burrs and smaller chips can also be obtained as vibration
assistance is added
Research on Self-balancing Two Wheels Mobile Robot Control System Analysis
The paper presents the research on self-balancing two-wheels mobile robot control system analysis with experimental studies. The research problem in this work is to stabilize the mobile robot with self-control and to carry the sensitive things without failing in a long span period. The main objective of this study is to focus on the mathematical modelling of mobile robot from laboratory scale to real world applications. The numerical expression with mathematical modelling is very important to control the mobile robot system with linearization. The fundamental concepts of dynamic system stability were utilized for maintaining the stability of the constructed mobile robot system. The controller design is also important for checking the stability and the appropriate controller design is proportional, integral,and derivative – PID controller and Linear Quadratic Regulator (LQR). The steady state error could be reduced by using such kind of PID controller.The simulation of numerical expression on mathematical modeling was conducted in MATLAB environments. The confirmation results from the simulation techniques were applied to construct the hardware design of mobile robot system for practical study. The results from simulation approaches and experimental approaches are matched in various kinds of analyses. The constructed mobile robot system was designed and analyzed in the control system design laboratory of Yangon Technological University (YTU)
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