Model Based Prediction and Control of Machining Deflection Error in Turning Slender Bars

2011 ◽  
Author(s):  
Parikshit Mehta ◽  
Laine Mears
Keyword(s):  
Control Strategies ◽  
Process Models ◽  
Machining Process ◽  
Open Architecture ◽  
Cnc Machine Tools ◽  
Effective Control ◽  
Machining Accuracy ◽  
Machining Processes ◽  
Model Based Control ◽  
Model Based

Model based control of machining processes is aimed at improving the performance of CNC systems by using the knowledge of machining process to reduce cost, improving machining accuracy and improving overall productivity. In this paper, real time control of the machining process to maintain dimensional quality when turning a slender bar is addressed. The goal is to actively control the machining feed rate to maintain constant and predicable deflection through a combined force-stiffness model integrated to the process controller. A brief review is presented on manufacturing process models, process monitoring, and model based control strategies such as Model Predictive Control (MPC). The main objective of this paper is to outline a method for deploying such models to process control. To demonstrate this, model of the deflection of the workpiece under tool cutting forces is developed. Unknown process parameters have been calculated using series of FEA simulations and verified with basic experimental data. A simple but effective control strategy has been formulated and simulated. In the initial results, the diameter of bar is maintained within 1.04% error with controller as opposed to up to 4% error without controller. Ultimately, the goal is to deploy such control strategies in the industrial control system. With the continual development in physical understanding of machining processes and affordable computing technology (both software and hardware) coupled with Open Architecture Control (OAC) applied to CNC machine tools, such approaches are now computationally feasible. This will be an enabling factor to deploy model based control in an industrial environment. The last section discusses the proposed hardware architecture to achieve this. The paper concludes with a brief plan for the future work and a summary.

Lyapunov Control Strategy for Thermoelectric Cooler Activating an Ice-Clamping System

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Alexandra Mironova ◽  
Paolo Mercorelli ◽  
Andreas Zedler
Keyword(s):  
Manufacturing Systems ◽  
Control Strategies ◽  
Industrial Applications ◽  
Machining Process ◽  
Free Form ◽  
Cooling Power ◽  
Machining Processes ◽  
Clamping System ◽  
Ice Strength ◽  
Free Form Surfaces

Deformation-free clamping plays an important role in manufacturing systems helping to ensure zero-defect production. The fixture of workpieces during machining processes poses challenges not only for microparts but also for thin-walled pieces or free-form surfaces in macromanufacturing. To address this challenge, a nontraditional adhesive technique, using frozen water to clamp, is introduced in this paper. By increasing the cooling power and thus reducing the temperature of the clamping plate, higher adhesive ice strength and, therefore, a safer clamping system during machining process, can be achieved. The objective of this investigation is to ensure a stable low temperature and to compensate for thermal disturbances. Thanks to their structural robustness, Lyapunov-based control strategies demonstrate an appropriate capability to achieve these results in real industrial applications. Model design of the clamping system as well as simulation and experimental results are shown and discussed.

scholarly journals Modified Mechanistic Model Based on Gaussian Process Adjusting Technique for Cutting Force Prediction in Micro-End Milling

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Xiaoping Liao ◽  
Zhenkun Zhang ◽  
Kai Chen ◽  
Kang Li ◽  
Junyan Ma ◽  
...  
Keyword(s):  
Gaussian Process ◽  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Mechanistic Model ◽  
Machining Process ◽  
Mechanistic Models ◽  
Machining Processes ◽  
Model Based ◽  
Micro End Milling

Micro-end milling is in common use of machining micro- and mesoscale products and is superior to other micro-machining processes in the manufacture of complex structures. Cutting force is the most direct factor reflecting the processing state, the change of which is related to the workpiece surface quality, tool wear and machine vibration, and so on, which indicates that it is important to analyze and predict cutting forces during machining process. In such problems, mechanistic models are frequently used for predicting machining forces and studying the effects of various process variables. However, these mechanistic models are derived based on various engineering assumptions and approximations (such as the slip-line field theory). As a result, the mechanistic models are generally less accurate. To accurately predict cutting forces, the paper proposes two modified mechanistic models, modified mechanistic models I and II. The modified mechanistic models are the integration of mathematical model based on Gaussian process (GP) adjustment model and mechanical model. Two different models have been validated on micro-end-milling experimental measurement. The mean absolute percentage errors of models I and II are 7.76% and 6.73%, respectively, while the original mechanistic model’s is 15.14%. It is obvious that the modified models are in better agreement with experiment. And model II performs better between the two modified mechanistic models.

scholarly journals Model-Based Control Strategy for Autonomous Vehicle Path Tracking Task

2020 ◽  
Vol 12 (1) ◽  
pp. 35-45
Author(s):  
Ahmad Reda ◽  
József Vásárhelyi
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Autonomous Vehicle ◽  
Steering System ◽  
Model Based Control ◽  
Model Based ◽  
Common Control ◽  
Vehicle Path ◽  
And Performance ◽  
Robust Systems

AbstractDespite the advanced technologies used in recent years, the lack of robust systems still exists. The automated steering system is a critical and complex task in the domain of the autonomous vehicle’s applications. This paper is a part of project that deals with model-based control strategy as one of the most common control strategies. The main objective is to present the implementations of Model Predictive Control (MPC) for an autonomous vehicle steering system in regards to trajectory tracking application. The obtained results are analysed and the efficiency of the use of MPC controller were discussed based on its behaviour and performance.

Monitoring and Control of Thermal Expansion Effect on Machining Process of Aluminum Alloy Parts

2015 ◽  
Vol 809-810 ◽  
pp. 33-38 ◽  
Author(s):  
Ştefan Adrian Moldovan ◽  
Vasile Năsui
Keyword(s):  
Thermal Expansion ◽  
Aluminum Alloy ◽  
Milling Process ◽  
Machining Process ◽  
Machining Accuracy ◽  
Technological Problem ◽  
Monitoring And Control ◽  
Machining Processes ◽  
Thermal Expansion Effect ◽  
Expansion Effect

In this paper we present a technological problem encountered in the machining accuracy of the parts for aerospace made of aluminum alloy extruded profile with length up to 10 meters. Those parts have very tight tolerances and on milling process appear several factors that influence the repeatability of machining processes, the main one being the thermal expansion effect.

Research on Fault Knowledge Base Technology of High-End CNC Machining System

2011 ◽  
Vol 308-310 ◽  
pp. 35-40
Author(s):  
Xiao Li Xu ◽  
Bin Ren ◽  
Yun Bo Zuo ◽  
Guo Xin Wu
Keyword(s):  
Knowledge Base ◽  
Cutting Tool ◽  
Cnc Machining ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Construction Technology ◽  
Test Platform ◽  
Machining System ◽  
Wear Condition

In the high-end CNC machining process, the stability and reliability of the running state of the machining system directly affects the machining accuracy and work-piece quality. In order to effectively ensure the reliable, stable, safe operation of the high-end CNC machining system, the fault knowledge base technology construction for the cutting tool system is carried out. It focuses on the high-end CNC machine tools, and build the condition monitoring system test platform with cutting tool system as the core; the fault sample acquisition method based on the rough set theory is proposed; a knowledge base model construction technology is conducted; and the network-based sample acquisition test platform is established, so as to provide users with data information on the operation of cutting tool system, and provide the key test techniques for the generation mechanism of the dynamic performance and wear condition of the operation of cutting tool system and for the analysis of the intrinsic correlation between the characteristic parameters and wear condition of cutting tools.

Sign in / Sign up

Export Citation Format

Share Document