Study On Control System Of Mobile Wood Chipper

Mobile wood chipper is one of the more efficient equipments processing the disperse forestry bioresources. At present, the domestic mobile wood chipper requires manual intervention of feeding when the cutting load goes beyond the maximal value. Because it lacks of effective feeding control technology. This paper designs a set of automatic control system based on the self-designed mobile wood chipper, the system can automatically stop feeding when cutting drum is overloaded and restart feeding when it goes down, in that way it can effectively prevent the engine flameout; it can also adjust the feeding speed according to the different diameter of wood. The main research contents and results were summarized as follows:1. A feeding experiment based on mobile wood chipper experimental prototype was done. The test showed that cutting speed decreased significantly when cutting large diameter wood, which can easily cause engine flameout. The test also shows that the steady cutting speed of cutting drum is different when cutting different diameter wood.2. Completing the design of control solution. The cutting load is represented by the speed of cutting drum. The system will stop feeding when the decreasing speed of cutting drum is closed to the minimum speed, which is1520r/min; it can also adjust feeding speed in line with different diameter of wood referring to the test data,50r/min,37r/min and23r/min by the small, medium and large diameter wood. There is a manual rod designed for the controlling of feeding roller working state,such as feed, reverse and stop.3. R&D of software and hardware. Hardware system which is based on ATmega16microcontroller, can read speed sensor’s data by sampling circuit and calculate the speed of cutting drum and feed roller; using the output power amplifier circuit the system can control solenoid valve and proportional flow valve. The software of the control system consists of the minimum cutting speed control program, feeding speed control program and manual control rod state reading program.4. Debugging and testing of the control system. Tests show that under the control of the system mobile wood chipper is stable and reliable; the system effectively help avoide the engine flameout caused by peak cutting load over the normal level and improve the cutting efficiency; the pass rate of wood chips reaches95.52%.