Research On Application Of IPC Control System In Drilling And Measuring Equipments For Geotechnical Engineering

Presently, the automation of general geotechnical engineering construction equipments is still not high in our country. It needs to make comprehensive research on technology and equipments for geotechnical drilling and rock and soil thermophysical properties measuring to make the construction more efficient and economical. It includes geotechnical rig research and in-situ measuring equipment of rock and soil thermophysical properties research. The information, automation and intelligence of the equipments is a direct reflection of geotechnical engineering construction level. Improving the level can raise the construction efficiency and reduce the construction cost to great extent. Also, it becomes a improtant standard of reaching the international leading level.To solve the problem above, this paper makes a deep research on industrial computer control system of the industrial automatic control field in present. And two industrial computer control systems which applied to geotechnical rig and in-situ measuring equipment of rock and soil thermophysical properties have been constructed according to the equipments'characteristics and application requirements.Industrial computer control system is an important part of the industrial automatic control technology. The whole system is composed of control system hardware, control algorithm and upper computer industrial configuration software. The system hardware constructs signal detection and control channels of the whole system. During the application processes, it realizes collection of various parameters, signal processing, control signal output and actuator control. The design of control algorithm makes the automatic control strategy to be realized. And it makes the equipments execute actions according to expected control mode. The development of upper computer configuration software realizes the creatings of software system and engineering database, editing of human machine interfaces. The parameters can be monitored real-timely. Data reports can be generated. And the software system can give alarm when the working conditions are abnormal. The most important is that the development of upper computer configuration software programmes various control procedures of data processing and control functions.In the industrial computer control system hardware of geotechnical rig, an industrial computer is applied as measuring and control core. Various sensors are adopted to collect the drilling parameters, and then the parameters will be processed and analog-digital converted by PLC input module. After data operation by upper computer, the control signal will be digital-analog converted and isolated. Finally, the control signal will be sent to proportional relief valve and variable displacement pump of hydraulic system to control the feeding and rotation system of the rig. In the algorithm design, incremental PID algorithm and its improved algorithm have been designed, according to the principles and models of the proportional relief valve and variable displacement pump and actual conditions. Accumulation compensation method is applied to inhibit integral saturation. Incomplete differential PID method is applied to decrease system oscillation. Differential forward method is applied to avoid system overshoot. PID algorithm with dead zone is applied to avoid frequent movement. The sampling period and control patameters of PID control has been adjusted. It make the feeding and rotation system of the rig realize closed loop PID control. It can much improve the bad situations of slow response, big overshoot and poor stability of the system when the control signal step changes. In the development of upper computer configuration software, Kingview 6.5 is applied to build the software system of the rig control system. Engineering document has been designed and the database has been established. All the configuration functions has been edited, and the parameters calculation formulas and automatic control strategy programs has been programmed. It realizes the functions of drilling parameters measuring and control.In the industrial computer control system hardware of in-situ measuring equipment of rock and soil thermophysical properties, the industrial computer is also applied as measuring and control core. Various sensors are adopted to collect the measuring engineering parameters. And then the parameters will be processed and analog-digital converted by intelligent analog module. After data operation by upper computer, the control signal will be digital-analog converted and isolated. Finally, the control signal will be sent to electric tee valve to control the opening, then to regulate the mixing proportion of high and low temperature flow, furthermore, to control the temperature difference of the ground heat exchanger entry and exit. It can ensure to input constant heat current into the ground heat exchanger. In the algorithm design, a pure time delay control algorithm of Smith predictor combined with incremental PID algorithm has been designed, according to the principles of electric tee valve and actual conditions. The sampling period of pure time delay control algorithm has been adjusted. Temperature difference control has the characteristics of big control inertia and long lag time. The pure time delay control can much improve the dynamic response characteristics of system, make the control more stable and fast, and reduce the overshoot. In the development of upper computer configuration software, MCGS 6.2 is adopted to build the software system of the measuring equipment. The develop process is the same as it of rig industrial computer control system.A series of experimental research of drilling and measuring equipments for geotechnical engineering have been conducted. Firstly, the hardware systems have been installed. The adjusting results show that the hardware communication is normal, signal measuring is accurate, operation state is stable and the functions of actuators are normal. By the no load operation experiment of actuators of rig hydraulic system, the results show that the movements of feeding system and rotation system are normal, the actuators'steady state performance is satisfactory, the linearity of electro-hydraulic proportional control is excellent. A continuous step response test of actuators of the in-situ measuring equipment of rock and soil thermophysical properties has been conducted. The result shows that the control element has the advantages of sensitive reaction and fast action speed. At last, the practical engineering applications were conducted. The results show that the control effects of the two equipments are quite good. And the construction efficiency and safety are improved greatly.To research on application of industrial computer control system in drilling and measuring equipment for geotechnical engineering, in order to improve the geotechnical engineering construction efficiency. In the research of this paper, the key technology of industrial control field was utilized. It provides a new idea of improving the automation level of geotechnical engineering equipments. More industrial automation control technology and theories should be applied in drilling and measuring equipments for geotechnical engineering in the future, so that it can overall improve the automation level of drilling and measuring equipments for geotechnical engineering and construction efficiency of our country.