A Control System for Chatter Avoidance by Ramping the Spindle Speed

1998 ◽  
Vol 120 (4) ◽  
pp. 674-683 ◽  
Author(s):  
E. Soliman ◽  
F. Ismail
Keyword(s):  
Control System ◽  
High Speed ◽  
Spindle Speed ◽  
Cutting Process ◽  
Statistical Indicator ◽  
Speed Range ◽  
Force Signal ◽  
On Line ◽  
Full Immersion ◽  
R Value

This paper presents a new control system for chatter avoidance in milling. The control system monitors the cutting process using a statistical indicator named the R-value which is computed from the cutting force signal. When chatter is detected, the control system ramps the spindle speed in search of a speed at which chatter ceases. The system does not involve time consuming computations and therefore is suitable for on-line implementation. Also, it does not interrupt the cutting process by halting the feedrate or the spindle speed. Simulations showed that the control system has a significant chatter avoidance potential in the high speed range, and also for partial and full immersion cuts. The system was implemented successfully to avoid chatter in slotting and half immersion down milling.

Some Applications of State and Parameter Estimation to Machine Tool Problems: I—Applications of Nonsequential Estimation

1970 ◽  
Vol 92 (3) ◽  
pp. 633-646 ◽  
Author(s):  
Russell F. Henke
Keyword(s):  
Machine Tool ◽  
Dynamic Model ◽  
High Speed ◽  
Metal Cutting ◽  
Sequential Estimation ◽  
Cutting Process ◽  
Damping Factor ◽  
Process Data ◽  
Identification Schemes ◽  
On Line

A general introduction to the area of off-line and on-line identification of systems is given, and applications of these techniques to machine tool problems, especially adaptive or optimal control, are discussed. The problem of identifying the dynamic model of the metal cutting process is given special emphasis. A general formulation of the nonsequential or off-line estimation problem is presented using state variable notation, so that nonlinearities and time varying parameters may be present. Two techniques tailored to the use of the high-speed digital computer are developed to solve this general problem. The first utilizes a direct multivariable search to match the output, of an assumed dynamic model to actual experimental observations in a least squares sense. The second method uses a modified quasilinearization procedure. Controlled digital experiments are used to refine and test the proposed techniques. The two algorithms are then applied to actual experimental cutting process data. Estimates of the cutting stiffness and damping factor in the dynamic model of the cutting process are obtained, thus demonstrating the effectiveness of the developed nonsequential identification schemes, and showing that the assumed linear dynamic model adequately represents the cutting process. A later paper will consider sequential estimation applications.

Development of an On-Line Bowl-Shaped Diamond Grinding Wheel Dresser

2006 ◽  
Vol 304-305 ◽  
pp. 545-549
Author(s):  
Jia Shun Shi ◽  
Guang Qi Cai ◽  
Ming Hu ◽  
Q.Y. Liang
Keyword(s):  
Control System ◽  
High Speed ◽  
Control Method ◽  
Wheel Speed ◽  
Grinding Wheel ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
On Line ◽  
And Control

In this paper, a new on-line diamond grinding wheel dresser, which is comprised of high-speed rotatory dressing wheel, micro-feed mechanism and control system, is presented. The principle of micro-feed machine working at requiring dressing depth, the control method of the dressing wheel speed adjusting and dressing depth, and structure of the control system are also introduced. The experiments we have done show that the dresser reach the goal of diamond grinding wheel on-line dressing.

A State-Space Model for Monitoring Thermally Induced Preload in Anti-Friction Spindle Bearings of High-Speed Machine Tools

1994 ◽  
Vol 116 (3) ◽  
pp. 372-386 ◽  
Author(s):  
J. L. Stein ◽  
J. F. Tu
Keyword(s):  
State Space ◽  
Machine Tools ◽  
High Speed ◽  
The State ◽  
Spindle Speed ◽  
Spindle System ◽  
Thermally Induced ◽  
On Line ◽  
Bearing Preload ◽  
High Speed Machine

Catastrophic and premature bearing failure caused by excessive thermally induced bearing preload is a major design problem for spindle bearings of high-speed machine tools. Due to a lack of a low cost and easy to maintain on-line preload measuring technique, the traditional solution is to limit the maximum spindle speed and the initial bearing preload. This solution is incompatible with the need to increase machining productivity, which requires increasing the spindle speed, and to increase product quality (surface finish, dimensional accuracy), which requires increasing (or at least not decreasing) the preload to keep the spindle system stiff. This paper proposes a dynamic mathematical model of the spindle system, which can be used as part of a model-based monitoring system for estimating the spindle bearing preload. The model is derived from physical laws of heat transfer and thermoelasticity and represents the transient preload behavior induced by uneven thermal expansions within a bearing. The state-space structure of the model provides for efficient sensor selection and easy conversion into a state observer for on-line preload estimation. The state variables defined in the model are the temperatures of the outer ring/housing, the rolling elements, and the inner ring, while the induced preload is an algebraic function of these states. The model, which is successfully validated for two typical configurations of high speed spindle assemblies, provides a tool for understanding the basic mechanics of induced preload as a function of initial preload, spindle speed, and housing cooling conditions. Most importantly, the model meets the requirements as the basis of a preload observer developed by the authors. While the observer is not presented in this paper, basic issues related to its development are discussed.

scholarly journals Stall Inception and the Prospects for Active Control in Four High Speed Compressors

1997 ◽  
Author(s):  
I. J. Day ◽  
T. Breuer ◽  
J. Escuret ◽  
M. Cherrett ◽  
A. Wilson
Keyword(s):  
Control System ◽  
Active Control ◽  
High Speed ◽  
Rotating Stall ◽  
Collaborative Project ◽  
Stall Inception ◽  
Speed Range ◽  
Full Speed ◽  
Stall Warning ◽  
Stall Control

As part of a European collaborative project, four high speed compressors were tested to investigate the generic features of stall inception in aero-engine type compressors. Tests were run over the full speed range to identify the design and operating parameters which influence the stalling process. A study of data analysis techniques was also conducted in the hope of establishing early warning of stall. The work presented here is intended to relate the physical happenings in the compressor to the signals that would be received by an active stall control system. The measurements show a surprising range of stall related disturbances and suggest that spike-type stall inception is a feature of low speed operation while modal activity is clearest in the mid speed range. High frequency disturbances were detected at both ends of the speed range and non-rotating stall, a new phenomenon, was detected in three out of the four compressors. The variety of the stalling patterns, and the ineffectiveness of the stall warning procedures, suggests that the ultimate goal of a flightworthy active control system remains some way off.

Fuzzy Control of Spindle Torque in High-Speed Milling Processes

2006 ◽  
Vol 128 (4) ◽  
pp. 1014-1018 ◽  
Author(s):  
Rodolfo Haber-Guerra ◽  
Steven Y. Liang ◽  
José R. Alique ◽  
Rodolfo Haber-Haber
Keyword(s):  
Control System ◽  
Feed Rate ◽  
High Speed ◽  
Fuzzy Controller ◽  
Removal Rate ◽  
Spindle Speed ◽  
Torque Control ◽  
Numerical Control ◽  
Open Architecture ◽  
High Speed Milling

This paper presents the design and implementation of a two-input/two-output fuzzy logic-based torque control system embedded in an open architecture computer numerical control (CNC) for optimizing the material removal rate in high-speed milling processes. The control system adjusts the feed rate and spindle speed simultaneously as needed to regulate the cutting torque using the CNC’s own resources. The control system consists of a two-input (i.e., torque error and change of error), two-output (i.e., feed rate and spindle speed increment) fuzzy controller, which is embedded within the kernel of a standard open control. Two approaches are tested, and their performance is assessed using several performance measurements. These approaches are a two-input/two-output fuzzy controller and a single-output (i.e., feed rate modification only) fuzzy controller. The results demonstrate that the proposed control strategy provides better accuracy and machining cycle time than other strategies, thus increasing the metal removal rate.

Delayed Reference Control for Hotwire Cutting of Expandable Polystyrene Foam

2005 ◽  
Vol 128 (1) ◽  
pp. 360-365 ◽  
Author(s):  
Paolo Gallina
Keyword(s):  
Time Delay ◽  
Force Control ◽  
Interaction Force ◽  
Cutting Process ◽  
Practical Implementation ◽  
Theoretical Predictions ◽  
Force Signal ◽  
On Line

This paper presents the ideation and implementation of a 2-axes robotic system for hotwire cutting of polystyrene plates. In particular, since the quality of the cutting process is strongly affected by, among others, the interaction force between the hotwire and the workpiece, an accurate force control is required. The force control module, which is referred to as delayed reference control (DRC) belongs to the category of nontime based controllers. According to the DRC theory, the desired input reference xd is a function of time and a variable, which plays the role of a time delay: xd(t−T). The time delay T is properly calculated on-line according to the measured force signal in such a way to improve the cutting process quality during the interaction phase. DRC theory and its practical implementation on a 2-axes robot are presented as well as an accurate description of the cutting process. In fact, experimental results validate theoretical predictions.

Intelligent Quality Control System Based on Machine Vision of Multi-Line

2014 ◽  
Vol 513-517 ◽  
pp. 1192-1196
Author(s):  
Ju Bao Qu ◽  
Shu Juan Wang
Keyword(s):  
Quality Control ◽  
Control System ◽  
Machine Vision ◽  
High Speed ◽  
Image Acquisition ◽  
Quality Control System ◽  
On Line ◽  
Working Principle ◽  
Software And Hardware ◽  
Industrial Software

Testing for a variety of different industrial objects, this paper designed a multi on-line machine vision based on intelligent quality control system solutions. Microvision based on the company introduced the MV-8002 image acquisition card and the MV-VS1394 camera visual inspection of industrial software and hardware structure and the working principle of a high-speed online learning model of intelligent foreign recognition, it described the image acquisition card and the camera with the application and the software development. by the applications case, and the further evidence of the reliability of this system.

Update on High-Speed Milling Dynamics

1990 ◽  
Vol 112 (2) ◽  
pp. 142-149 ◽  
Author(s):  
S. Smith ◽  
J. Tlusty
Keyword(s):  
High Speed ◽  
Metal Removal ◽  
Removal Rate ◽  
Spindle Speed ◽  
Stability Lobe ◽  
Milling Operations ◽  
Force Signal ◽  
The Stability ◽  
Milling Dynamics ◽  
Selection Of

As spindle speeds and power have increased, the possibility of using the stability lobe phenomena to substantially increase the metal removal rate has become more attractive, and selection of optimum spindle speeds has become an important consideration. It is shown that, for many milling operations, it is desirable to set the tooth frequency equal to the natural frequency. At this spindle speed, the development of resonant forced vibration is actually inhibited by regeneration of waviness. An algorithm is presented for automatically selecting the optimum spindle speed based on the cutting force signal.

Automatic Calibration of Clamp-On Ultrasonic Flowmeter Based on Fieldbus Control System

2011 ◽  
Vol 301-303 ◽  
pp. 1730-1734
Author(s):  
Qing Qiang Hou ◽  
Yong Mei Huang ◽  
Zhi Liang Zhang ◽  
Bin Sun
Keyword(s):  
Control System ◽  
High Speed ◽  
Electromagnetic Flowmeter ◽  
Ultrasonic Flowmeter ◽  
Practical Significance ◽  
Automatic Calibration ◽  
Calibration System ◽  
Non Invasive ◽  
Comparison Results ◽  
On Line

In practical application, some flowmeters are not allowed to be calibrated off-line periodically, thus on-line calibration is necessary to be implemented in workplace [1]. As a non-invasive flowmeter, the clamp-on ultrasonic flowmeters are widely used in on-line calibration system. As a master flowmeter, ultrasonic flowmeters must be calibrated before or during using. Based on multiple fieldbus control system, an automatic calibration system for the ultrasonic flowmeter was designed. The comparison results between ultrasonic and electromagnetic flowmeter obtained during the process of calibrating manifest that the automatic calibration system is effective and reliable. Because of the good interoperability of the multiple fieldbus, other flowmeters with different protocols can be connected into this system easily. With the high speed development of fieldbus technology, this has great practical significance in flowmeter calibration.

scholarly journals Stall Inception and the Prospects for Active Control in Four High-Speed Compressors

1999 ◽  
Vol 121 (1) ◽  
pp. 18-27 ◽  
Author(s):  
I. J. Day ◽  
T. Breuer ◽  
J. Escuret ◽  
M. Cherrett ◽  
A. Wilson
Keyword(s):  
Control System ◽  
Active Control ◽  
High Speed ◽  
Collaborative Project ◽  
Stall Inception ◽  
Speed Range ◽  
Full Speed ◽  
Stall Warning ◽  
Stall Control ◽  
Engine Type

As part of a European collaborative project, four high-speed compressors were tested to investigate the generic features of stall inception in aero-engine type compressors. Tests were run over the full speed range to identify the design and operating parameters that influence the stalling process. A study of data analysis techniques was also conducted in the hope of establishing early warning of stall. The work presented here is intended to relate the physical happenings in the compressor to the signals that would be received by an active stall control system. The measurements show a surprising range of stall-related disturbances and suggest that spike-type stall inception is a feature of low-speed operation while modal activity is clearest in the midspeed range. High-frequency disturbances were detected at both ends of the speed range and nonrotating stall, a new phenomenon, was detected in three out of the four compressors. The variety of the stalling patterns, and the ineffectiveness of the stall warning procedures, suggests that the ultimate goal of a flightworthy active control system remains some way off.

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