The Implement of Hydraulic Control System for Large- Scale Railway Maintenance Equipment Based on PLC

Transcription

1 Sensors & Transduers 2014 by IFSA Publishing, S. L. The Implement of Hydrauli Control System for Large- Sale Railway Maintenane Equipment Based on PLC Junfu YU, * Hairui WANG Information and Automation Building, Kunming University of Siene and Tehnology, Chenggong Distrit, Kunming, Yunnan Provine, China milady987@163.om Reeived: 20 Marh 2014 /Aepted: 30 April 2014 /Published: 31 May 2014 Abstrat: Programmed Logi Controller (PLC) is the digital alulation operation system, whih is speially designed for industrial working environment. This paper proposed the implement of hydrauli ontrol system for large-sale railway maintenane equipment based on PLC. This implement pursued the purpose of aurate ontrol of hydrauli working units of large-sale railway maintenane equipment. Large-sale railway maintenane equipment should always work in effiient statement. Fousing on this requirement, the reliability design of hardware for urrent leakage and impulse urrent whih is proposed in the paper is neessary. This paper proposed Triple Modular Redundany (TMR) for relative horizontal hek of working units linking bridge. This paper also proposed the method to prevent the urrent leakage and impulse urrent. As for hydrauli valves, this paper proposed PID algorithm to realize the ontrol of Analogue Closed-Loop. Copyright 2014 IFSA Publishing, S. L. Keywords: Large-sale railway maintenane equipment, Hydrauli ontrol, PLC, TMR, PID. 1. Introdution A Programmable Logi Controller, PLC or Programmable Controller is a digital omputer used for automation of eletromehanial proesses, suh as ontrol of mahinery on fatory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and manufature industries. Unlike general-purpose omputers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to eletrial noise, and resistane to vibration and impat. Programs to ontrol mahine operation are typially stored in battery-baked-up or non-volatile memory. A PLC is an example of a hard real-time system sine output results must be produed in response to input onditions within a limited time, otherwise unintended operation will result. In the late 1960 s, PLC s were developed to eliminate the large ost involved in hanging ompliated relay based mahine ontrol systems. These systems were inflexible and ompliated, whih their major rewiring or omplete replaement was neessary every time as the prodution requirements hanged and ontrol sequenes had to be modified. Frequent requirement hanges made the ost unaeptable. In this situation the thought of replaing relay systems with flexible miroproessor based on Programmable logi ontrollers (PLC) was a revolutionary step in the industrial ontrol area. The real PLC whih is seleted as the implement of the system in this paper is shown in Fig. 1. PLC s have been used for several years at different areas appliations. They are the main ontrol elements of several subsystems whih require relatively slow data monitoring: the radiation ontrol, 222 Artile number P_2062

2 personal safety, fire and smoke alarm. All these subsystems are very effetive and have great reliability. omponent had a disadvantage of urrent leakage as the urrent usage higher than the threshold value. In this situation, arranging a parallel resistane between sensors and PLC an solve this problem, shown as Fig. 2. Fig. 2. The hardware design for input urrent leakage. The eq. (1) shows how to alulate the resistane value and the power usage of the resistane. Fig. 1. MITSUBISHI F1-40MR PLC. Large-sale railway maintenane equipment is mainly used for the onstrution of onrete pouring and railway works. Large-sale railway maintenane equipment or a ballast tamper or tamping mahine is a mahine used to tamp the trak ballast under railway traks to make the traks more durable. Prior to the introdution of mehanial tampers, this task was done by manual labor with the help of beaters. As well as being faster, more aurate, more effiient and less labor-intensive, tamping mahines are essential for the use of onrete sleepers sine they are too heavy (usually over 250 kg) to be paked into the ballast by hand. As the sleepers of the railway gets heavier, hydrauli ontrol system was the way to do the heavy work. Hydrauli ontrol system mainly about 4 parts: 1) The relative horizontal ontrol of working units linking bridge; 2) The pressure ontrol of hydrauli pump; 3) The ontrol of hydrauli eletromagneti station valves; 4) The speed ontrol of the hydrauli driven wheels; all four parts are used PLC as the ontrol system omponent [1]. 2. The Hardware Design for Reliability of Current Leakage and Impulse Current 2.1. The Hardware Design for Reliability of Input Current Leakage As the sensors of limit swith of the PLC ontrol system are used for input omponents, the usage of input urrent threshold value is 1.3 ma, as this R K w W, (1) 3.43 I 5 R The formula shown in Eq. (1) are the resistane value and power usage alulation formulas, I represents the input devie urrent, R represents the resistane and W represents the power usage of the resistane The Hardware Design for Reliability of Output Current Leakage It may have some mistaken ations whih ause output urrent leakage of the PLC load iruit. In this situation, arranging a bypass parallel resistane between load power supply and PLC an solve this problem, shown as Fig. 3. Fig. 3. The hardware design for output urrent leakage. The eqn. (2) is the bypass resistane value alulation formulas, I represents the output leakage urrent, R represents the bypass resistane and U ON represents the start pressure of the load power supply. U ON R, (2) I 223

3 2.3. The Hardware Design for Reliability of Impulse Current The transistors or bidiretional thyristor inside in PLC an suffer the impulse urrent 10 times than itself rated urrent. To forbidden too muh impulse urrent to the load iruit, there are two ways to solve this problem, this paper proposed serials-resistane. In this situation, arranging a serial resistane between load power supply and PLC an solve this problem, shown as Fig. 4. Fig. 5. The tamping unit of the ballast temper. Fig. 4. The hardware design for impulse urrent. 3. The Relative Horizontal Control of Working Units Linking Bridge As the ballast tamper working, for eah rail there is a tamping unit attahed to the main frame by means of vertial guide olumns and a lift/lowering hydrauli ylinder. The tamping unit onsists of tamping tool whih is as known as arms, a hydrauli vibration motor, a vibration shaft and an eentri flywheel. For eah sleeper, a tamping unit is provided with four pairs of tamping arms: one eah side of the sleeper, 16 tamping arms are used for tamping a single sleeper. All of these arms are onneted to the linking bridge, shown as Fig. 5. PLC takes the relative horizontal angle as the feedbak variable, to alulate this relative horizontal angle by the ontrol algorithm to identify the temper arming working statement information as PUSH or PULL. By the working statement information, PLC an ensure the requirement of relative horizontal angle less than 1. The relative horizontal ontrol [2, 3] an guarantee the quality of the railway maintenane. To seure the relative horizontal ontrol of the linking bridge, this paper proposed to arrange two sensors for measuring the relative horizontal to the ground of the linking bridge; and arrange another two sensors at the bottom of the working ar of the ballast tamper for measuring the relative horizontal to the ground of the ballast temper. PLC ontrol system got the input signals for all the sensors to alulate the relative horizontal. This paper proposed Triple Modular Redundany (TMR) [6, 7] for data olletion and Markov Model [4, 5] for testing Triple Modular Redundany reliability. Assuming eah tunnel module failure rate is a onstant λ; Fault diagnose sale is C; maintenane rate is μ; and at one moment there was only one module failed. There are three modules in this system: 1) PLC; 2) Sensors for relative horizontal detetion; 3) Hydrauli ontrol valve. The Markov Model state proess desription is shown as below: 1) State 0 represents normal working state of the system; 2) Stare 1 represents one of the three tunnel module prediable system failure, system an deide by the priniple of two taken two; 3) State 2 represents two of the three tunnel modules having prediable system failure, system ould not deide the system working state, whih means system ould not distinguish whih tunnel module has unpreditable failure, in another way State 2 also represents Failure-Suess state; 4) State 3 represents one of the three tunnel modules having unpreditable failure, system an deide by the priniple of three taken two, it also means reliable suess state; 5) State 4 represents two of the three tunnel modules having failure, one of the two failed tunnel modules has the preditable failure and has been shut down, another failed tunnel module has the unpreditable failure, system annot deide by the priniple of two taken two; 6) State 5 represents all of the three tunnel modules having failure whether preditable or unpreditable, system is highly dangerous. The state transition diagram is shown as Fig. 6. pj(t) represents system State j ( j {0,1,2,3,4,5} ) at the time t, pj(t) initialization is pj(0) {1,0,0,0,0}, the probability of pj(t) is alulated by matrix equation P ' (t) P(t) A. 224

4 1 3 3 (1 ) (1 ) 1 ( ) 2 (1 ) 2 (1) Fig. 6. The state transition diagram of Markov Module for Triple Modular Redundany. Aording to Fig. 6, the state transition diagram of Markov Module for Triple Modular Redundany shows that State 0, State 1 and State 3 an guarantee the system reliability; State 0, State 1, State2, State 3 and State 4 represent system at safety working state. The probability of system reliability R(t) alulation formula is shown in eqn. (3). R(t) p0(t) p1(t) p3(t), (3) 4. The Software Design of PLC Control System for Hydrauli Pump The hydrauli pump drives the ballast tamper tamping units arms at the right hydrauli pressure, PLC ontrol system for hydrauli pump is the ore system of the whole PLC ontrol system. To enhane the hydrauli pump operation pressure auray, this paper proposed PID algorithm [8, 9, and 10] for PLC ontrol system. PLC ontrol system for hydrauli pump mainly inluded four parts: 1) PLC; 2) the pressure sensors; 3) the proportional amplifier; 4) the proportional relief valve. The main struture of PLC ontrol system for hydrauli pump is shown in Fig of the omputation. The ontrol algorithm main proesses are: 1) As V>0, the real pressure is higher, PLC ontrols the proportional relief amplifier to turn the proportional relief valve down until the V=0; 2) As V<0, the real pressure is higher, PLC ontrols the proportional relief amplifier to turn the proportional relief valve up until the V=0; PID represents Proportional, Integration and Differential. The PLC ontrol system for hydrauli pumps is a lose iruit ontrol system; PID algorithm is responsible to the output ontrol of the iruit whih means PID algorithm works on ontrolling the signal from PLC to Hydrauli Pumps. 1) represents the differene value (V) of real pressure (PV) and rated pressure (RP). 2) U is the output variable, U(t) is the funtion of time (t), the U(t) is the ombination of Proportional, Integration and Differential, its equation is shown in eqn. (4). 3) K represents the gains of output. 4) U initial represents the initialization value of U. t U(t) Kn Ki dtu K / 0 initial d dt, (4) As PLC omputation is disrete omputation, PID equation must be disretization the disrete equation of U(t) is shown in eqn. (4). 1) Un represents the output alulation value at the n sampling time. 2) n represents the differene value at the n sampling time. represents the differene value at the n-1 3) n 1 sampling time. 4) K D represents the oeffiient of Differential. 5) K I represents the oeffiient of Integration. n U K K U K ( ), (5) n n I i initial D n n 1 i1 And PID algorithm program flow hart is shown as Fig Conlusions Fig. 7. Struture of PLC ontrol system for hydrauli pump. PLC is responsible to ollet the signals from the pressure sensors. When the system starts, the pressure sensors send input signals, whih represent the real pressure of eah hydrauli pump, to PLC. Then PLC ompares these real pressure signals with the rated pressure signals, there is a differene value (V) This paper proposed the implement of PLC hydrauli ontrol system for Large-Sale railway maintenane equipment. The reliability hardware designs make PLC more stable and reliable at working time. Triple Modular Redundany for relative horizontal hek of tamping units linking bridge make the linking bridge at relative horizontal, guarantee the tamping arms working at the proper status. Based on the PID algorithm PLC an aurately ontrol the hydrauli units, whih tamping arms work at the aurate step, make the whole railway maintenane proess more effiieny and aurate. 225

5 Fig. 8. PID algorithm program flow hart. Aknowledgements This work is supported by the National Natural Siene Foundation of China (Grand No ) and Yunnan Provinial Department of Eduation Researh Fund (Grand No ). Referenes [1]. Yousif I. Al Mashhadany, Design and implement of a programmable logi ontroller (PLC) for lassial ontrol laboratory, Intelligent Control and Automation, Vol. 3, Issue 1, 2012, pp [2]. Yang Jihua, Sheng Qian, Zhang Yumin, Influene fator study on relative horizontal displaement of underground rok powerhouse under earthquake, in Proeedings of the International Conferene on Consumer Eletronis, Communiations and Networks (CECNet), XianNing, April 2011, pp [3]. Ryszar Malarski, Kamil Nagórski, Marek Woźniak, Appliation of inlinometer measurements for relative horizontal displaement investigations on landslide grounds, Reports on Geodesy and Geoinformatis, Vol. 94, Issue 1, 2013, pp [4]. Wen Zhang, Ding Liu, Rui-Rui Ji, The appliation of hidden Markov model in building geneti regulatory network, Journal of Biomedial Siene and Engineering, Vol. 3, Issue 6, 2010, pp [5]. Steven L. Sott, Gareth M. James, Catherine A. Sugar, Hidden Markov models for longitudinal omparisons, Journal of the Amerian Statistial Assoiation, Vol. 100, Issue 470, 2005, pp [6]. Jian-Xiao Zou, Zheng-Qian Zhang, Hong-Bing Xu, Design of heartbeat invalidation deteting mehanism in triple modular redundany multi-mahine system, COMPEL: The International Journal for Computation and Mathematis in Eletrial and Eletroni Engineering, Vol. 29, Issue 2, 2010, pp [7]. Gong Rui, Chen Wei, Liu Fang, Dai Kui, Wang Zhiying, Modified triple modular redundany struture based on asynhronous iruit tehnique, in Proeedings of the 21 st IEEE International Symposium on Defet and Fault Tolerane in VLSI Systems (DFT' 06), 2006, pp [8]. Mohammad A. K. Alia, Using PLC for ustomdesign of a PID/PWM program to ontrol a heater temperature, Amerian Journal of Applied Sienes, Vol. 4, Issue 5, 2007, pp [9]. Zhan Lei, Zhao Jing, Implement of inrement-model PID ontrol of PLC in onstant-pressure water system, in Proeedings of 8 th International Conferene on Eletroni Measurement & Instruments (ICEMI 2007), [10]. Jia Minzhi, Guo Chao, Shi Xiaomin, Study on the appliation of the single neuron adaptive PID ontroller in prestressed tension devie, in Proeedings of the IEEE 10 th International Conferene on Eletroni Measurement & Instruments (ICEMI 2011), Measurement Touh the World, 2011, Vol.4, pp Copyright, International Frequeny Sensor Assoiation (IFSA) Publishing, S. L. All rights reserved. ( 226