Design And Study On The Two-wheel Equipment For Traveling Speed Measurement Of Agricultural Machinery

The traveling speed is a very important parameter in the performance research and identification experiment of agricultural machinery.The typical measurement speed methods are mark post measurement method, fifth wheel method, radar speed measurement method and so on in our country. The mark post measurement method which is used as a simple measurement and fifth wheel method which is used as a formal measurement are used widely in the study and identification of agricultural machinery. According to the measurement principle and practice, the fifth wheel method is perfect to be used to measure speed on the hard and flat road. Therefore, the method has been adopting in the Auto trade widely. But if this method is used in the field(the surface of field is undulated, soft and covers with straw and stubble), which will bring biggish error and fluctuation.The purpose of this project is to study a two—wheel equipment which orients to measure speed and distance in the field. The idea is expelling the random error by the surface of field and getting exact result by the two-wheel speed signal's on-line treatment. It is improved to the single-wheel structure of conventional fifth wheel device.Firstly, a two-wheel equipment is designed and processed specially with the purpose of adopting sensor fixing and fitting the feature of two-wheel measurement.Secondly, on the basis of the scope of agricultural machinery's traveling speed, incremental rotary encoder (360rpm) is used as speed sensor in order to approach to transient speed. By way of fixing encoder and coaxial degree adjustment bridge-shape bracket and claw-shape linker are designed and processed.Thirdly, measurement device fixes the controlling core—single-chip microprocessor system , data output device—subminiature printer, power supply— storage battery(12v) and voltage stabilization circuit. From the structure to the function, all the device can meet the requirement of the data collection and on-line continuous speed measurement. The measurement system's hardware structure design and related software design have been introduced in this paper.Thirdly, a mass of experiments are proceeded in order to master systemic error and stochastic error of the system, these errors' brought factors are analyzed, some schemes are addressed by way of weakening error.Fourthly, comparing single wheel's experiment with two wheels', a two-wheel optimal algorithm is gained. Making use of analysis of variance and similar method sum up the fact that value of measurement nears to the real value by the algorithm. The measurement precise can be 1%. .Finally, for improving security of system, this paper introduces some anti-disturbance measures.