scholarly journals A Real-Time Dressing Method for Metal Lapping Pads Based on the Thermal-Deformation Effect

2021 ◽  
Author(s):  
Lingyu Zhao ◽  
Huiying Zhao ◽  
Hairong Wang ◽  
Ruiqing Xie ◽  
Mingchen Chao ◽  
...  
Keyword(s):  
Real Time ◽  
Thermal Deformation ◽  
Surface Shape ◽  
Coolant Temperature ◽  
Deformation Model ◽  
Real Time Control ◽  
Dressing Method ◽  
Deformation Effect ◽  
Material Loss ◽  
Time Control

Abstract The surface shape and accuracy of the metal lapping pad are important factors that affect the performance of the lapping process for flat optical components. A real-time control system for metal-lapping-pad surface shape (RCLPS) based on the bimetal thermal-deformation effect is proposed. Unlike traditional dressing methods (e.g., turning dressing with a diamond tool), real-time dressing based on the RCLPS system is a material-loss-free and in-process dressing method. A full-aperture lapping turntable based on the RCLPS system was designed, and the working heat was analyzed. A thermal-deformation model was established through regression analysis. Finally, experiments were conducted to verify the functionality of the RCLPS system. During turning dressing (turntable rotational speed nm = 100 rpm), the thermal-deformation error caused by the working heat of the turntable-shaft system was compensated by the RCLPS system. During the lapping process for optical elements (nm ≤ 20 rpm), the real-time dressing of the lapping-pad surface shape was controlled by the coolant temperature of the RCLPS system, permitting optimization and adjustment of the process performance of the plane optical component. The effectiveness and practicality of the RCLPS system were demonstrated experimentally.

Control-Oriented Modeling of Thermal Deformation of Machine Tools Based on Inverse Solution of Time-Variant Thermal Loads with Delayed Response

2004 ◽  
Vol 126 (2) ◽  
pp. 286-296 ◽  
Author(s):  
S. Fraser ◽  
M. H. Attia ◽  
M. O. M. Osman
Keyword(s):  
Control System ◽  
Real Time ◽  
Thermal Deformation ◽  
Heat Conduction Problem ◽  
Integrated System ◽  
Machining Accuracy ◽  
Delayed Response ◽  
Frequency Noise ◽  
Real Time Control ◽  
Time Control

With the new emerging technologies of high performance machining and the increasing demand for improved machining accuracy in recent years, the problem of thermal deformation of machine tool structures is becoming more critical than ever. The major problem in implementing real-time control systems is the difficulty of measuring the relative thermal displacement between the tool and the workpiece during machining. Therefore, the design of a generic multi-axis control system requires the development of control-based models to estimate the transient thermal load and the thermal deformation of the structure in real-time. To satisfy the stringent accuracy and stability requirements of the control system, a new inverse heat conduction problem IHCP solver is developed. This solution is capable of including the inertia effect and the delay in the thermal response, in order to accommodate situations where the measured points cannot be located near the heat source, which may be buried into the structure. Experimental validation of these models showed their inherent stability even when the temperature measurements are contaminated with random errors. The excellent computational efficiency of the integrated system, which is well suited for real-time control applications involving multi-dimensional structures, was achieved by incorporating an inverse numerical Laplace transformation procedure. The results also showed that the thermal deformation transfer function behaves as low-pass filters, and as such it attenuates the high frequency noise associated with temperature measurement error.

Control-Oriented Modeling of Thermal Deformation of Machine Tools Based on Inverse Solution of Time-Variant Thermal Loads With Delayed Response

Manufacturing ◽  
2003 ◽  
Author(s):  
S. Fraser ◽  
M. H. Attia ◽  
M. O. M. Osman
Keyword(s):  
Control System ◽  
Temperature Measurement ◽  
Real Time ◽  
Thermal Deformation ◽  
Integrated System ◽  
Machining Accuracy ◽  
Delayed Response ◽  
Frequency Noise ◽  
Real Time Control ◽  
Time Control

With the new emerging technologies of high performance machining and the increasing demand for improved machining accuracy in recent years, the problem of thermal deformation of machine tool structures is becoming more critical than ever. The major problem in implementing real-time control systems is the difficulty of measuring the relative thermal displacement between the tool and the workpiece during machining. Therefore, the design of a generic multi-axis control system requires the development of control-based models to estimate the transient thermal load and the thermal deformation of the structure in real-time. To satisfy the stringent accuracy and stability requirements of the control system, a new inverse heat conduction problem IHCP solver is developed. This solution is capable of including the inertia effect and the delay in the thermal response, in order to accommodate situations where the measured points cannot be located near the heat source, which may be buried into the structure. Experimental validation of these models showed their inherent stability even when the temperature measurement are contaminated with random errors. The excellent computational efficiency of the integrated system, which is well suited for real-time control applications involving multi-dimensional structures, was achieved by incorporating an inverse numerical Laplace transformation procedure. The result also showed that the thermal deformation transfer function behaves as low-pass filters, and as such it attenuates the high frequency noise associated with temperature measurement error.

A Real Time Control Architecture for Continuously Managing Patients in a Care Unit

1995 ◽  
Vol 34 (05) ◽  
pp. 475-488
Author(s):  
B. Seroussi ◽  
J. F. Boisvieux ◽  
V. Morice
Keyword(s):  
Real Time ◽  
Linear Time ◽  
Treatment Plan ◽  
Control Architecture ◽  
Real Time Control ◽  
Time Representation ◽  
Time Control ◽  
Continuous Support ◽  
Definition Of ◽  
Computerized System

Abstract:The monitoring and treatment of patients in a care unit is a complex task in which even the most experienced clinicians can make errors. A hemato-oncology department in which patients undergo chemotherapy asked for a computerized system able to provide intelligent and continuous support in this task. One issue in building such a system is the definition of a control architecture able to manage, in real time, a treatment plan containing prescriptions and protocols in which temporal constraints are expressed in various ways, that is, which supervises the treatment, including controlling the timely execution of prescriptions and suggesting modifications to the plan according to the patient’s evolving condition. The system to solve these issues, called SEPIA, has to manage the dynamic, processes involved in patient care. Its role is to generate, in real time, commands for the patient’s care (execution of tests, administration of drugs) from a plan, and to monitor the patient’s state so that it may propose actions updating the plan. The necessity of an explicit time representation is shown. We propose using a linear time structure towards the past, with precise and absolute dates, open towards the future, and with imprecise and relative dates. Temporal relative scales are introduced to facilitate knowledge representation and access.

Real-time Control for Mobile Robot Considering Environmental Changes

2007 ◽  
Vol 73 (12) ◽  
pp. 1369-1374
Author(s):  
Hiromi SATO ◽  
Yuichiro MORIKUNI ◽  
Kiyotaka KATO
Keyword(s):  
Mobile Robot ◽  
Real Time ◽  
Environmental Changes ◽  
Real Time Control ◽  
Time Control

Using graphs to construct a math model of a microcontroller-based system for preset rate control of a flywheel motor to be used in high-dynamics spacecraft

2020 ◽  
pp. 126-134
Author(s):  
Vladimir V. NEKRASOV
Keyword(s):  
Real Time ◽  
Rotation Rate ◽  
Control Function ◽  
Real Time Control ◽  
Math Model ◽  
The Real ◽  
Time Control ◽  
Power Matrix ◽  
High Dynamics ◽  
Stated Problem

Developing a microcontroller-based system for controlling the flywheel motor of high-dynamics spacecraft using Russian-made parts and components made it possible to make statement of the problem of searching control function for a preset rotation rate of the flywheel rotor. This paper discusses one of the possible options for mathematical study of the stated problem, namely, application of structural analysis based on graph theory. Within the framework of the stated problem a graph was constructed for generating the new required rate, while in order to consider the stochastic case option the incidence and adjacency matrices were constructed. The stated problem was solved using a power matrix which transforms a set of contiguous matrices of the graph of admissible solution edge sequences, the real-time control function was found. Based on the results of this work, operational trials were run for the developed control function of the flywheel motor rotor rotation rate, a math model was constructed for the real-time control function, and conclusions were drawn about the feasibility of implementing the results of this study. Key words: Control function, graph, incidence matrix, adjacency matrix, power matrix, microcontroller control of the flywheel motor, highly dynamic spacecraft.

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