Research On Key Technology Of Automatic Control System In Large-sized Trencher And Pipe-layer

There are about88000000acres of saline land to remake in China,and pipe modified alkali engineering is the efficient way to solve the problem. Pipe laying and drainage is an important content of improving the alkali-saline land engineering. Foreign ditch pipe laying equipment has high production efficiency and good construction quality, but the equipment is so expensive and technical support is much difficult. In China, self-propelled trencher pipe laying machine has small horsepower, low working speed, and the degree of automation is not high. Therefore it is very necessary to develope relavant equipment with independent intellectual property rights that can fit our national condition. The key problems in automatic control system of the trencher and pipe-layer(1KPZ-250) is studied according to the requirements of the subject. Automatic level control, automatic navigation control and ditching depth automatic control are finally realized by use of hydraulic drive technology, electro-hydraulic control technology, sensor technology, GPS technology, human-machine environment engineering modularization technology,and so on. The first two control system are highlighted. The main research contents are as follows,(1) Automatic control system of the trencher and pipe-layer(1KPZ-250) is overall designed. On the basis of summing up the ditch pipe laying machine and related control system at home and abroad, working principle and basic structure of the trencher and pipe-layer(1KPZ-250) is analyzed and automatic control method in automatic level, automatic walking and ditching depth is put forward.(2) The automatic level control system which is based on feedback control theory is designed, and the hardware part includes single axis angle sensor module, AD module, PIC module, power module, and drive load module. Experiments have been done as follows:the angle of sensor module and voltage corresponding relation, leveling control precision and sensitivity, static angle acquisition error, dynamic response, levelling performance. The results show that, the relationship between angle of sensor and voltage is approximately linearity. It is more obvious especially in small angle range.Sample-collecting error can reach0.098%. Dynamic performance indicators of the system are as follows:delay time Td=1.36s, rising time Tr=1.55s, peak time Tp=2.95s, overshoot σ%=0.2%, adjusting time Ts=5.42s.These indicate that the dynamic quality of the system is good. It can satisfy the automatic level control system.(3) GPS automatic navigation control system is developed.lt consists of GPS receiver, vehicle controller, field controller, speed sensor and so on.Vehicle controller is given by the set path walking control strategy, and field controller outputs a control signal to adjust the walking speed and achieves the purpose of walking the line. Field test of the system is completed. Then the results are analyzed and processed. It shows that, GPS automatic navigation control system can accurately control the machine according to the planning path.Even if its initial position and path planning has a large distance, the machine can also realize automatic navigation fastly. Yaw error can be controlled within±10cm, the machine can finally run with maximum yaw distance9.94cm. It proves that GPS differential positioning navigation accuracy can meet the requirements of the machine.