Sensorless Cutting Force Estimation in Large Scale Ball-Screw-Driven Machine Tool

2016 ◽  
Vol 1136 ◽  
pp. 645-650 ◽  
Author(s):  
Yuki Yamada ◽  
Yasuhiro Kakinuma ◽  
Takamichi Ito ◽  
Jun Fujita ◽  
Atsushi Tada ◽  
...  
Keyword(s):  
Machine Tool ◽  
Cutting Force ◽  
Control Systems ◽  
Friction Force ◽  
Large Scale ◽  
Metal Cutting ◽  
Estimation Method ◽  
Ball Screw ◽  
Force Estimation ◽  
Non Linear

The cutting force is widely regarded as being the most valuable information when observing a metal cutting process. Considering practicability, indirect cutting force measurement methods which forego additional sensors have been studied in academic field. Disturbance observer-based cutting force estimation method was known as a typical example, and its validity was verified in linear motor driven stage. However, accurate cutting force estimation is still difficult in ball-screw driven stage because of non-linear friction and resonance. In this study, feasibility of sensorless cutting force estimation was verified by using large scale commercial machine tool. Considering that the motion of rotational and translational elements independently, cutting force observer (CFOB) was modeled as two-degree-of-freedom system. The CFOB was mounted to control systems of both stage and spindle head which were driven by ball-screw and servo motor. While friction force and torque have non-linear position dependence, high repeatability was confirmed. Thus, their non-linearity could be attenuated by identifying friction force and torque beforehand machining operation. From experimental results, it was shown that tooth-pass frequency and second harmonics component of the cutting forces could be estimated accurately by using the CFOB. The results were acquired from control systems of both stage and spindle head.

Sensorless Cutting Force Estimation in Ball-Screw-Driven System Using Triple-Inertia Model

2014 ◽  
Vol 1017 ◽  
pp. 619-623
Author(s):  
Yuki Yamada ◽  
Yasuhiro Kakinuma ◽  
Takamichi Ito ◽  
Jun Fujita ◽  
Makoto Sawazaki ◽  
...  
Keyword(s):  
Cutting Force ◽  
Estimation Method ◽  
Ball Screw ◽  
Accurate Estimation ◽  
Force Estimation ◽  
Resonance Frequencies ◽  
Driven System ◽  
Output System ◽  
Simulation Results ◽  
Inertia Model

In this paper, we propose cutting-force-estimation method for a ball-screw-driven system using triple inertia model. In many cases, dual-inertia model is applied to describe the dynamic behavior of the ball-screw-driven system. In this paper, triple-inertia model is applied and cutting force was estimated without additional sensors, such as dynamometer. The cutting force observer is designed, regarding the ball-screw-driven system as two input and three output system. Simulation results indicate that the proposed method enables accurate estimation around the resonance frequencies. Experimental results showed that the proposed method could monitor external force without being interrupted by the inertia forces.Nomenclature

Numerical Simulation of Metal Cutting Process Based on ANSYS/LS-DYNA

2015 ◽  
Vol 727-728 ◽  
pp. 335-338 ◽  
Author(s):  
Song Jie Yu ◽  
Di Di Wang ◽  
Xin Chen
Keyword(s):  
Cutting Force ◽  
Metal Cutting ◽  
Plastic Material ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Machining Process ◽  
Linear Deformation ◽  
Deformation Problem ◽  
Non Linear ◽  
Elastic Plastic Material

Cutting process is a typical non-linear deformation problem, which involves material non-linear, geometry non-linear and the state non-linear problem. Based on the elastic-plastic material deformation theory, this theme established a strain hardening model. Build the simulation model of two-dimensional orthogonal cutting process of workpiece and tool by the finite element method (FEM), and simulate the changes of cutting force and the process of chip formation in the machining process, and analyzed the cutting force, the situation of chip deformation. The method is more efficient and effective than the traditional one, and provides a new way for metal cutting theory, research of material cutting performance and cutting tool product development.

Modeling and Simulation of Process and Structure Interactions Considering Turning Operations

2009 ◽  
Author(s):  
Michael F. Zaeh ◽  
Florian Schwarz
Keyword(s):  
Machine Tool ◽  
Cutting Force ◽  
Metal Cutting ◽  
Material Behavior ◽  
Force Model ◽  
Machine Tool Structure ◽  
Simulation Based ◽  
Turning Center ◽  
Simplifying Assumptions ◽  
Input Variables

A consideration of the dynamic interaction between the machine tool structure and the cutting process is required for the prediction and optimization of machining tasks through simulation. This paper outlines a modular, analytical cutting force model applicable to common turning processes. It takes into account the dynamic material behavior and nonlinear friction ratios on the rake face as well as heat transfer phenomena in the deformation zones. In order to overcome simplifying assumptions in analytical cutting force descriptions and to incorporate the chip formation process into the analysis, specific input variables are determined in a metal cutting simulation based on the Finite Element Method (FEM). On the machine tool structure side, the setup of a parametric FEM model is presented. The accuracy of both the machine tool and cutting force models was verified experimentally on a turning center.

Precise Cutting Force Estimation by Hybrid Estimation of DC/AC Components

2020 ◽  
Author(s):  
Taiki Sato ◽  
Shuntaro Yamato ◽  
Yasuhiro Imabeppu ◽  
Naruhiro Irino ◽  
Yasuhiro Kakinuma
Keyword(s):  
Cutting Force ◽  
Thrust Force ◽  
End Milling ◽  
Moving Average ◽  
Low Frequency ◽  
Friction Model ◽  
Ball Screw ◽  
Estimation Accuracy ◽  
Force Estimation ◽  
Feed Direction

Abstract External sensor-less cutting force estimation using a load-side disturbance observer (LDOB) has potential to estimate the cutting force with high accuracy in both feed and cross-feed directions. However, the accuracy of its low frequency components in feed direction decrease due to effect of the friction and heat of a ball-screw-driven stage. In this study, DC and AC components of the cutting force is estimated by different methods; friction-compensated motor thrust force and LDOB, and the cutting force was estimated in real time by hybridizing them. In particular, regarding the friction model, the dynamic and static characteristics of the friction force in each axis (X, Y, Z) were identified from the idling test results. In addition to the model that depends on the velocity, the characteristics of the friction that depend on the position was also identified and considered when compensating for the motor thrust force. Then, a simple moving average filter with an appropriate window length is applied to the cutting force by LDOB and motor thrust force, and the DC component error of LDOB is corrected by that of motor thrust force. The validity of the proposed method was evaluated through end-milling tests. The experimental results showed that estimation accuracy of cutting force using the proposed method can be greatly improved in feed directions. On the other hand, in cross-feed direction, the cutting estimation was performed using the conventional LDOB.

Evaluation of DC Servo Machine Tool Feed Drives as Force Sensors

1986 ◽  
Vol 108 (4) ◽  
pp. 279-288 ◽  
Author(s):  
J. L. Stein ◽  
D. Colvin ◽  
G. Clever ◽  
C.-H. Wang
Keyword(s):  
Machine Tool ◽  
Cutting Force ◽  
Force Sensor ◽  
Lumped Parameter Model ◽  
Ball Screw ◽  
Model Parameters ◽  
Cnc Machine ◽  
Feed System ◽  
Feed Force ◽  
System Components

Unmanned machine tools as part of an automated factory require reliable, inexpensive sensors to provide machine and process information to the controller. The electric current in the DC motor of a CNC machine tool can be inexpensively measured and used to calculate the tool/workpiece cutting force and the forces associated with drive system components. In order to characterize the bandwidth, sensitivity and accuracy of current monitoring on the feed system of a CNC lathe, a dynamic lumped parameter model of this sensor system is developed. The model is used to identify the system components that have a dominant effect on the behavior of the sensor. Tests were conducted in order to determine the model parameters, verify the model, and determine the signal-to-noise (S/N) ratio of the sensor. The bandwidth of this sensor is predicted to be 80 Hz. Tests show that the S/N ratio is low but can be improved by a trade-off with the system bandwidth. The bandwidth is limited by the characteristics of the SCR amplifier. In addition, the sensitivity and accuracy of calculating the feed force component of the cutting force from the total current used by the feed motor is limited by the pitch of the ball screw and friction coefficient variations in the slide. Feed system design changes, to improve the S/N ratio of the feed system as a tool and machine force sensor, are discussed.

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