Dual sliding mode contouring control with high accuracy contour error estimation for five-axis CNC machine tools

A-axis is an essential assembly in the five-axis CNC machine tools, and its positioning precision directly affects the machining accuracy and surface quality of the parts. Considering the influence of parameters perturbation and uncertain cutting force on the control precision of the A-axis, a nonlinear dynamics model of the A-axis system is established, which reveals the relationships among the drive torque, the load torque, the motion direction and the system parameters. Then, two adaptive sliding mode controllers (ASMC) are designed. The first one is based on the bipolar sigmoid function, which can adjust the switching gain and the boundary layer thickness adaptively, then, equilibrium between the tracking error and the chattering can be achieved. The second one is a compound adaptive controller constituted by the traditional sliding mode controller (TSMC) and an internal controller that is based on the hyperbolic tangent function. When the state trajectory comes into the boundary layer, the TSMC will be replaced by the internal controller, thus, the adaptive controller can continuously switch between these two controllers, which can effectively eliminate the high-frequency chattering in the TSMC. Stability of these two controllers is guaranteed by the Lyapunov theory. Experimental results demonstrate the effectiveness and feasibility of the proposed ASMC, which can smooth the input chattering and reduce the tracking error by 16.62% and 21.44%, respectively.

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Using ADAMS Application on Mechanism Simulation of New Multiaxis Machines

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.479-480.396 ◽

2013 ◽

Vol 479-480 ◽

pp. 396-400 ◽

Cited By ~ 1

Author(s):

Yi Ming Lee ◽

Kuei Shu Hsu ◽

Shyue Bin Chang

Keyword(s):

Machine Tools ◽

Aerospace Industry ◽

High Accuracy ◽

Manufacturing Industries ◽

Cnc Machine Tools ◽

Kinematics Analysis ◽

Cnc Machine ◽

New Model ◽

Five Axis ◽

Real Machine

Aerospace industry or manufacturing industries might demand high class more-axis CNC machine tools for the high accuracy needs for machining. The multiaxis CNC machine development in simulation of the new model application seems to be necessary for the market. The main purpose of this paper is to study the mechanisms of new model multiaxis CNC machine tools and build process to develop the characteristics of machine tools. Through the computer simulation and graphic animation, users can observe their relationships of each movement on the new model multiaxis CNC machine tools. Using ADAMS to realize the motion commands and coordinate the kinematics is proposed. The prototype demonstrates the feasibility and kinematics analysis of new model five-axis CNC for real machine.

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Modeling and Control of Contouring Errors for Five-Axis Machine Tools—Part II: Precision Contour Controller Design

Journal of Manufacturing Science and Engineering ◽

10.1115/1.3123336 ◽

2009 ◽

Vol 131 (3) ◽

Cited By ~ 25

Author(s):

Burak Sencer ◽

Yusuf Altintas

Keyword(s):

Machine Tools ◽

High Speed ◽

Sliding Mode ◽

Kinematic Model ◽

Cnc Machine Tools ◽

Sculptured Surfaces ◽

Cnc Machine ◽

Control Approach ◽

Tool Paths ◽

Five Axis

The accurate tracking of tool-paths on five-axis CNC machine tools is essential in achieving high speed machining of dies, molds, and aerospace parts with sculptured surfaces. Because traditional CNCs control the tracking errors of individual drives of the machine, this may not lead to desired contouring accuracy along tool-paths, which require coordinated action of all the five drives. This paper proposes a new control approach where the tool tip and tool orientation errors, i.e., the contouring errors, are minimized along the five-axis tool-paths. The contouring error and kinematic model of the machine, which are presented in Part I of the paper, are used in defining the plant. A multi-input–multi-output sliding mode controller, which tries to minimize path tracking and path following velocity errors, is introduced. The stability of the system is ensured, and the proposed model is experimentally demonstrated on a five-axis machine tool. The path errors originating from the dynamics of five simultaneously active drives are significantly reduced.

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Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽

10.3390/ma14112913 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2913

Author(s):

Rafał Gołębski ◽

Piotr Boral

Keyword(s):

Machine Tools ◽

Coordinate Measuring Machine ◽

Optical Microscope ◽

Numerical Control ◽

Cnc Machine Tools ◽

Cnc Milling ◽

Cnc Machine ◽

Cylindrical Gears ◽

Measuring Machine ◽

Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

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