Research on the detection system for impact energy of pneumatic drill based on stress wave technique

The impact energy is very important as a performance parameter for pneumatic drill to optimize structure and improve performance. The method to detect impact energy of pneumatic drill with stress wave technology is used widely. According to the one dimension wave method, the working process of pneumatic drill is a process of energy transmission and conversion which in the form of stress wave, and the impact energy could be obtained accurately by detecting the stress wave through any point in the drill rod when piston collides drill rod. In which, the collecting and processing of waveform data is the key technology. In this paper, the theoretical foundation of stress wave technology is analyzed by using one dimension wave theory. According to this theory, the detection system for impact energy of pneumatic drill is designed and developed by using advanced micro computer measuring technology which based on electronic and computer technology. This system consists of calibration device, energy-absorbing device, signal collecting and processing system and PC control software. The calibration device and the energy absorbing device are used in getting calibration factor and reducing the influence of reflected wave respectively and they could meet the relevant requirements of GB5621-2008. The signal collecting and processing system is the most important part of the whole design and the stm32 single ship microcomputer with UCOSII micro operating system is used as control center of it to control the data collecting and processing. The PC control software written by VB could realize the interaction of human and this system. Under the standard experiment condition: atmosphere pressure is 101kPa, the temperature is 16 °C, the pressure of compression air is 0.4MPa., the impact energy of a Kaishan YO18 pneumatic drill is tested by using this system which developed by ourselves, and the stress waveform, the impact energy and impact frequency could be obtained and which indicate this system could collect the stress wave on the drill rod efficiently and calculate the values of impact energy and impact frequency. All of the experimental results could meets the factory index of this machine and the reliability of this system could be proven.