scholarly journals Estimation of Internal Maximum Thermal Stress of Tunnel Side Wall Lining Concrete During Construction Period

2021 ◽  
Author(s):  
Y H Duan ◽  
H M Yang ◽  
J P Yuan ◽  
L Su ◽  
W T Li

Thermal cracks in lining concrete of large section hydraulic tunnel usually occur in side walls during construction, and most of them are harmful penetrating cracks. In order to meet the needs of real-time rapid control for engineering design in construction period, nine influencing factors of maximum tensile of side wall lining concrete σmax during construction period are determined on the basis of comprehensive analysis of temperature stress effects and finite element simulations, and their influencing regularities are analyzed. Then the estimation formula of σmax and real-time control method of thermal crack are put forward. Through the application of real-time temperature control and crack prevention control of lining concrete in flood discharge tunnel, the estimation formula of σmax and the real-time thermal crack control method are proved to be correct and applicable.

2012 ◽  
Vol 594-597 ◽  
pp. 738-741 ◽  
Author(s):  
Yin Duan ◽  
Xing Hong Liu ◽  
Xiao Lin Chang

Main factors of the temperature control and crack prevention in arch dams are summarized. The Space-time Dynamic Control method in pipe cooling process and the Temperature Real-time Control and Decision Database System are introduced to help for temperature real-time control and rapid analysis. Successful application of these new techniques in the construction of Dagangshan arch dam indicates that the proposed method are of significant effectiveness on the temperature control and crack prevention, and have good application prospect in practical project.


1986 ◽  
Vol 108 (2) ◽  
pp. 146-150 ◽  
Author(s):  
P. G. Backes ◽  
G. G. Leininger ◽  
Chun-Hsien Chung

A joint coordinate self-tuning manipulator control method is presented which uses Cartesian setpoints. The method is capable of both position and hybrid control. Position and force errors are transformed from Cartesian coordinates to position and force errors at the joints. The position and force errors at each joint are combined into one hybrid error that is eliminated using pole-placement self-tuning. Real time position and hybrid control results are given. No prior knowledge of manipulator or load dynamics is required and real time control results show that the goal of consistent control with changing load dynamics is achieved. The major cause of error in position and hybrid control is the large friction effects in the joints.


2010 ◽  
Vol 42 ◽  
pp. 263-267
Author(s):  
Xin Long Kang ◽  
Dong Man Yu ◽  
Xue Ling Yang ◽  
Di Wang

This paper presents the methods and applications for the real-time control of CNC machining process quality in detail and clarifies the objectives of SPC for CNC machining, in order to enhance the understanding of the factors that cause instability to process system. Also, this paper adopts the methods and procedures for SPC to effectively serve the production of high-precision products for enterprises, in order to meet customers’ requirements and expectations.


2012 ◽  
Vol 241-244 ◽  
pp. 1392-1395
Author(s):  
Kun Qi Wang ◽  
Jing Wei Yang ◽  
Li Qun Lei

A new real-time control method for software CNC based on PC is proposed, and the data exchange methods are given. Both external and system clock interrupt are adopted as interpolation cycle to make up software CNC on PC. The data between the front procedures, interpolation module, and background procedures, application module, is exchanged by WDM. The method is verified in experiment, and the resolves show that the speed control and the interpolation operator are right, and whole software CNC is significantly improved.


2007 ◽  
Vol 129 (4) ◽  
pp. 527-533 ◽  
Author(s):  
G. Colin ◽  
Y. Chamaillard ◽  
G. Bloch ◽  
A. Charlet

This paper describes a real-time control method for non-linear systems based on model predictive control. The model used for the prediction is a neural network because of its ability to represent non-linear systems, its ability to be differentiated, and its simplicity of use. The feasibility and the performance of the method, based on on-line linearization, are demonstrated on a turbocharged spark-ignited engine application, where the simulation models used are very accurate and complex. The results, first in simulation and then on a test bench, show the implementation of the proposed control scheme in real time.


2012 ◽  
Vol 256-259 ◽  
pp. 1320-1324
Author(s):  
Da Wei Tong

Underground powerhouse of hydraulic and hydroelectric engineering is a large cavern group structure. Construction process of underground powerhouse is a complex system, whose construction schedule is associated with construction quality. It is necessary to arrange construction schedule adopting construction simulation method and combining with tunnel stability analysis, which can advance the level of construction organization design. By using real-time control theory and methodology, the real-time control model of construction schedule and quality was established, considering construction procedure, geological conditions and resource limitation. The real-time control method of construction schedule and quality was presented, and the practical control procedure was studied. Good effect is obtained through the application of the real-time control method for construction schedule and quality in one real underground powerhouse.


Author(s):  
Tri Cong Phung

Controlling accurately the position and velocity of robots in a given time is an important requirement in the industry. The open-source real-time operating systems not only have more advantages than the normal operating systems in both economy and flexibility but also meet the needs. This paper concentrates on building algorithms for controlling the robot trajectory in time using a modern real-time operating system called Linux-Xenomai. Firstly, the paper analyzes several advantages of the real-time operating system Linux-Xenomai comparing general operating systems and other real-time operating systems. Secondly, a real-time controller of a 5 degree-of-freedom (DOF) robot is built based on the real-time operating system Linux-Xenomai. After that, the paper proposes algorithms to test the ability of working in time of the robot. Finally, the real experiments are done to verify the proposed algorithms.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Hu Zhang ◽  
Shuzhi Zhao ◽  
Yang Cao ◽  
Huasheng Liu ◽  
Shidong Liang

In a traditional transit system, passenger arrival time and bus running time are typically random and uncoordinated. This randomness gives the appearance of unbalanced passenger demand and unreliable transit services. Therefore, this paper proposes a real-time control method for bus routes. In our method, buses skip some stations and turn back at appropriate stations, in order to balance passenger demand along the bus route and improve the overall transit service. Our real-time control method considers the typical changes in passenger demand and the stochastic travel time of buses. In this paper, the number of controlled vehicles at any given time is determined, and the bus holding time at the turn-back station is adopted. When implemented correctly, the optimal scheme indicates which stations should be skipped, where it is suitable for buses to turn back, and how long the holding time should be at turn-back stations, which in turn will minimize the total cost of a transit system. This paper formulates such an integrated strategy, presents the solution method of the formulation, and proves the validity of the real-time control method.


Sign in / Sign up

Export Citation Format

Share Document