Vibration Control of Relative Tool-Spindle Displacement for CNC Lathe With Pipe Frame Structure

2012 ◽  
Author(s):  
Yoshitaka Morimoto ◽  
Naohiko Suzuki ◽  
Yoshiyuki Kaneko ◽  
Minoru Isobe
Keyword(s):  
Machine Tool ◽  
Vibration Control ◽  
Machine Tools ◽  
Active Vibration Control ◽  
Relative Displacement ◽  
Frame Structure ◽  
Truss Structures ◽  
Welded Steel ◽  
Space Problem ◽  
Cnc Lathe

A new CNC lathe with a pipe frame bed has been developed. One requested improvement for machine tools is their downsizing by minimizing the number of mechanical parts. Some researchers aim to construct a desktop factory. This trend has been attracting a lot of attention lately in the industrial field. When a machine tool bed is designed using castings and/or welded steel plate structures to comply with this request, it is difficult to ensure space for chip evacuation because of the space limitations of solid body components. This led us to develop another type of structure for machine tools. A pipe frame bed has the ability to solve this problem. As represented by bridge trusses and flexible space structures, truss structures are traditional and fundamental in their design. This structure is expected to have enough space between the truss bars to solve the space problem. However, rigidity is the most significant issue for machine tools. Therefore, the desired rigidity is ensured by the use of diagonal braces. Based on this design concept, a CNC lathe whose frame consists of pipes, joints, and diagonal braces has been developed with enough rigidity and space utility for chip evacuation. From the viewpoint of machine tool usage, the rigidity and stable dynamic characteristics of the structure must be obtained. Then, real-time vibration control theory is applied to the relative displacement between the tool post and the spindle. Active vibration control is used to suppress specific relative vibration modes. In this paper, the effects of vibration control are evaluated by comparing the relative vibratory motion between the tool post and the spindle. Over 50% suppression has been achieved by applying vibration control to the target vibration mode. Additionally, using this control, the machined profile has been improved, and the roundness and harmonic analysis of the workpiece showed over 30% improvement.

Vibration Control of Relative Tool-Spindle Displacement for Computer Numerically Controlled Lathe With Pipe Frame Structure

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Yoshitaka Morimoto ◽  
Naohiko Suzuki ◽  
Yoshiyuki Kaneko ◽  
Minoru Isobe
Keyword(s):  
Control Theory ◽  
Machine Tool ◽  
Vibration Control ◽  
Machine Tools ◽  
Relative Displacement ◽  
Frame Structure ◽  
Vibration Modes ◽  
Space Problem ◽  
Cnc Lathe ◽  
Computer Numerically Controlled

A new computer numerically controlled (CNC) lathe with a pipe frame bed has been developed. This structure is expected to have enough space between the truss bars to solve the space problem and have enough rigidity for machine tools. Therefore, a CNC lathe whose frame consists of pipes, joints, and diagonal braces has been developed with enough rigidity and space utility for chip evacuation. From the viewpoint of machine tool usage, real-time vibration control theory is applied to control the relative displacement between the tool post and the spindle to suppress specific relative vibration modes.

Simulation-Based Dimensioning of the Required Actuator Force for Active Vibration Control

2018 ◽  
Vol 12 (5) ◽  
pp. 658-668 ◽  
Author(s):  
Robin Kleinwort ◽  
◽  
Philipp Weishaupt ◽  
Michael F. Zaeh
Keyword(s):  
Machine Tool ◽  
Vibration Control ◽  
Machine Tools ◽  
Active Vibration Control ◽  
Depth Of Cut ◽  
Force Model ◽  
Machining Processes ◽  
Simulation Based ◽  
Active Vibration ◽  
The Right

The material removal rates of machine tools are often limited by chatter, which is caused by the machine’s most flexible structural modes. Active vibration control systems mitigate chatter vibrations and increase the chatter-free depth of cut. The systems can be used for already-in-use machine tools in particular as a retrofit solution. Unfortunately, no dimensioning techniques exist to help in finding the right actuator size required for a specific machine tool. This publication presents a simulation-based dimensioning methodology that determines, based on a stability analysis, the required actuator force and bandwidth. First, the critical machining processes, based on machine tool specific parameters, are identified. Then, the required actuator force and bandwidth are determined with the help of a coupled simulation model that consists of a cutting force model, the machine’s structural dynamics, and a model of the active vibration control system.

scholarly journals Active vibration control for a CNC milling machine

2013 ◽  
Vol 228 (2) ◽  
pp. 230-245 ◽  
Author(s):  
DG Ford ◽  
A Myers ◽  
F Haase ◽  
S Lockwood ◽  
A Longstaff
Keyword(s):  
Control System ◽  
Tool Wear ◽  
Machine Tool ◽  
Vibration Control ◽  
Surface Finish ◽  
Machine Tools ◽  
Active Vibration Control ◽  
Milling Machine ◽  
Cnc Machine ◽  
Active Vibration

There is a requirement for improved three-dimensional surface characterisation and reduced tool wear when modern computer numerical control (CNC) machine tools are operating at high cutting velocities, spindle speeds and feed rates. For large depths of cut and large material removal rates, there is a tendency for machines to chatter caused by self-excited vibration in the machine tools leading to precision errors, poor surface finish quality, tool wear and possible machine damage. This study illustrates a method for improving machine tool performance by understanding and adaptively controlling the machine structural vibration. The first step taken is to measure and interpret machine tool vibration and produce a structural model. As a consequence, appropriate sensors need to be selected and/or designed and then integrated to measure all self-excited vibrations. The vibrations of the machine under investigation need to be clearly understood by analysis of sensor signals and surface finish measurement. The active vibration control system has been implemented on a CNC machine tool and validated under controlled conditions by compensating for machine tool vibrations on time-varying multi-point cutting operations for a vertical milling machine. The design of the adaptive control system using modelling, filtering, active vibration platform and sensor feedback techniques has been demonstrated to be successful.

Development of Pipe Structure Frame for CNC Lathe – Adaptation of Thermal Displacement Control

2012 ◽  
Vol 523-524 ◽  
pp. 503-508
Author(s):  
Naohiko Suzuki ◽  
Yoshitaka Morimoto ◽  
Yoshiyuki Kaneko ◽  
Hiroyuki Sugino ◽  
Minoru Isobe ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Machine Tool ◽  
Machine Tools ◽  
Frame Structure ◽  
Displacement Control ◽  
Thermal Displacement ◽  
Nc Machine Tool ◽  
Cnc Lathe ◽  
Nc Machine ◽  
Industrial Level

The miniaturization of many machine parts for machine tools is desired for the purpose of effective utilization of space, energy saving, and realization of desktop factory. To develop a compact and miniaturized NC machine tool, new downsized small parts such as hydraulic parts, pneumatic parts, electric parts and mechanical parts must be developed. These parts are not always satisfied for the practical usage in the present industrial level. Therefore, in spite of many requirements toward the miniaturization of the machine tool from the market, the miniaturized NC machine tool has not been put to practical use. The old-style structure of machine tools is one of the reasons of obstacle to solve this problem. We have proposed a newly developed ultra small size CNC lathe by using the pipe frame structure. The heat transfer between pipe elements and connecting block is affected strongly to the axial displacement. Therefore, the heat transfer between pipes can be insulated by the heat control on the connecting block. The thermal displacement control is realized by using the Peltier devices set on the connecting block. The results on the thermal displacement control of this structure and the effects on the cutting results are reported.

scholarly journals Experimental Active Vibration Control in Truss Structures Considering Uncertainties in System Parameters

2008 ◽  
Vol 2008 ◽  
pp. 1-14 ◽  
Author(s):  
Douglas Domingues Bueno ◽  
Clayton Rodrigo Marqui ◽  
Rodrigo Borges Santos ◽  
Camilo Mesquita Neto ◽  
Vicente Lopes
Keyword(s):  
Vibration Control ◽  
Dynamic Model ◽  
Electromechanical Coupling ◽  
Active Vibration Control ◽  
Experimental Methodology ◽  
Truss Structures ◽  
Linear Matrix ◽  
System Parameters ◽  
Identification Method ◽  
Active Vibration

This paper deals with the study of algorithms for robust active vibration control in flexible structures considering uncertainties in system parameters. It became an area of enormous interest, mainly due to the countless demands of optimal performance in mechanical systems as aircraft, aerospace, and automotive structures. An important and difficult problem for designing active vibration control is to get a representative dynamic model. Generally, this model can be obtained using finite element method (FEM) or an identification method using experimental data. Actuators and sensors may affect the dynamics properties of the structure, for instance, electromechanical coupling of piezoelectric material must be considered in FEM formulation for flexible and lightly damping structure. The nonlinearities and uncertainties involved in these structures make it a difficult task, mainly for complex structures as spatial truss structures. On the other hand, by using an identification method, it is possible to obtain the dynamic model represented through a state space realization considering this coupling. This paper proposes an experimental methodology for vibration control in a 3D truss structure using PZT wafer stacks and a robust control algorithm solved by linear matrix inequalities.

An Implementation of Intelligent CNC Machine Tools

2010 ◽  
Vol 44-47 ◽  
pp. 557-561 ◽  
Author(s):  
Chen Sheng Wang ◽  
Tjamme Wiegers ◽  
Joris S.M. Vergeest
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Tool Design ◽  
Cnc Machine Tools ◽  
Preliminary Evaluation ◽  
Machining Efficiency ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Machine Tool Design ◽  
Cnc Lathe

Improving the machining efficiency of CNC machine tools by introducing intelligence is now gaining more attention from both researchers and entrepreneurs. Based on the assessment of existing strategy of intelligent machine tool design, an implementation and preliminary evaluation of an intelligent CNC lathe has been reported in this paper. Techniques discussed in this paper are expected to benefit CNC machine tool researchers and designers in terms of the development of intelligent CNC machine tools.

scholarly journals INVESTIGATION OF LOCAL AND MODAL BASED ACTIVE VIBRATION CONTROL STRATEGIES ON THE EXAMPLE OF AN ELASTIC SYSTEM

2019 ◽  
Vol 19 (2) ◽  
pp. 32-45 ◽  
Author(s):  
Christoph PEUKERT ◽  
Patrick PÖHLMANN ◽  
Marcel MERX ◽  
Steffen IHLENFELDT ◽  
Jens MÜLLER
Keyword(s):  
Vibration Control ◽  
Machine Tools ◽  
Degrees Of Freedom ◽  
Elastic System ◽  
Control Strategies ◽  
Active Vibration Control ◽  
Modal Control ◽  
Control Approach ◽  
Control Loops ◽  
The Impact

Nowadays, feed axes are often equipped with multiple parallel-acting actuators in order to increase the dynamics of the machine tool. Also, additional actuators for active damping are widely used. Normally, the drives or actuators are controlled independently without consideration for the impact on each other. In contrast, by using the modal space control, the system can be decoupled and the modal control loops can be adjusted independently. This control approach is particularly suitable for motion systems, such as machine tools, which have more drives or actuators than degrees of freedom of movement. This paper deals with the pre-investigation of the modal-based vibration control for machine tools with additional actuators. The object of investigation is an elastic system with a movable saddle. The modal-based control is compared with a local control approach. The results obtained experimentally on the test rig are presented. The modal control is superior since, with the modal approach, each control loop corresponds to a specific vibration mode, and the control law for this loop is designed to provide the desired performance of the control system at the corresponding resonance frequency. The parameterisation of the control loops is simplified by modal control, since the modes can be controlled independently.

An adaptronic approach to active vibration control of machine tools with parallel kinematics

2008 ◽  
Vol 3 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Alexandra Ast ◽  
Steffen Braun ◽  
Peter Eberhard ◽  
Uwe Heisel
Keyword(s):  
Vibration Control ◽  
Machine Tools ◽  
Active Vibration Control ◽  
Parallel Kinematics ◽  
Active Vibration

Active Vibration Control for a Machine Tool With Parallel Kinematics and Adaptronic Actuator

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
Alexandra Ast ◽  
Peter Eberhard
Keyword(s):  
Machine Tool ◽  
Vibration Control ◽  
Position Control ◽  
Active Vibration Control ◽  
Linear Quadratic Regulator ◽  
Parallel Kinematics ◽  
Linear Quadratic ◽  
Control Approach ◽  
Authority Control ◽  
Active Vibration

The use of adaptronic components opens up interesting new possibilities for modern machine tools such as parallel kinematics. In this paper, two active vibration control concepts are designed for an adaptronic component of a parallel kinematic machine tool. The machine tool is modeled as a flexible multibody system model including a nonlinear flatness-based position control. Both the combination of a frequency shaped linear quadratic regulator with an active damping concept in a high authority control/low authority control approach and the H2 optimal control with gain scheduling show a high potential in the simulation to significantly increase the disturbance rejection or the tracking performance of the machine tool.

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