Paver Ultrasonic Ranging System

Ultrasonic non-contact balance beam is a mobile leveling benchmarks which based on the principle of ultrasonic distance measurement, With advantages of high accuracy easy installation, simple operation, safety and reliableness, etc. It can minimize the outside interference for equipment, thus ,obviously ,the speed and quality of asphalt concrete paver can be improved and the waste of raw materials and human is reduced. In this paper I analyses and compares a variety of commonly used ultrasonic ranging system, and Independently design and develope a high-precision ultrasonic ranging system applied to asphalt concrete paver balance beam.In this paper, I introduce the history and development of ultrasonic distance measurement and the working principle and commonly used detection methods of displacement detection based on ultrasonic technology,and analyse characters of Piezoelectric ultrasonic transducer. Theory of measurement based on ultrasonic and some usual means were mentioned. Key point which affect the precision of measurement was analysised and the high-precision measurement methods were mentioned. Introduce the process of the project in theory analysis, system collectivity design, system hardware circuit design and system software circuit design.This ranging system suggests a plan using a single-chip, CPLD and some analog circuits, and Comparising with the method only using single-chip and some analog circuits; it effectively improves the system precision and anti-interference ability. Using complex programmable logic device CPLD achieves ultrasonic transmitting and receiving, accurate record of echo time, and overcome the speed limits on single-chip microcomputer. Its measurement accuracy depends on the count frequency of CPLD. Single-chip is only responsible for read time from data port and computing, display, communication. Single-chip running speed will not impact the accuracy of test results, thus can reduce the level and cost of the single-chip, and avoided the shortage of traditional measurement depended on single-chip's frequency. Combination of the advantages of single-chip and CPLD, make the system circuit structure simple and reliable. In the same time the accuracy of ultrasonic distance detection improved significantly makes ultrasonic application and promotion in the field of precision measurement to be possible.