Design And Experimental Study Of Single Hanger Rail Sprayer In Greenhouse

In order to solve the problem that the laying of the track of the ground track sprayer occupies the ground resources of the greenhouse and is not conducive to the ground operation of the greenhouse.In this paper,a single hanger rail greenhouse sprayer is designed.The dynamic response of the sprayer during its operation is studied.The influence of running speed,liquid loading and span of the rail on the bending deformation and the vibration of the sprayer-hanger system is analyzed through experiments.According to vibration law,the sprayer is redesigned to reduce vibration.The main research contents include the following four aspects:(1)Structure design of single-rail greenhouse sprayerA single hanger rail greenhouse sprayer is designed,which mainly includes the running mode of the sprayer,the combination scheme of the driving wheel and the track,the scheme of the transmission system,the design of the frame and the construction scheme of the track to meet the operation requirements of the greenhouse.The overall dimensions of the prototype are 720mm×380mm×760mm,weight: 30 kg,running speed: 0.2~0.8m/s,tank capacity: 48 L,spray width: 3 m.(2)Establishing dynamic response of the hanging rail under the moving loadThe bending deformation mechanical model of the hanger rail under the action of the sprayer and the vibration model of the sprayer-rail system are established.According to the mechanical model,the corresponding motion equation is deduced for theoretical analysis.The results show that the bending deformation of the rail and the vibration of the sprayer-rail system are affected by the span of the rail,the running speed of the sprayer and the liquid loading.It provides a theoretical basis for deflection measurement test of hanger rail and vibration test of sprayer-rail system.(3)Deflection measurement test of hanger rail under moving loadAccording to the characteristics of the sprayer running on the hanger rail,a suitable deflection measurement scheme is selected,and the principle of deflection measurement is analyzed.The real-time angle changes of each measuring point during the operation of the sprayer are obtained through experiments.According to the relationship between the inclination angle and deformation of the simply supported beam,the conversion from inclination angle to deformation is realized through Matlab programming,and then the test results are analyzed.The test results show that the maximum deflection of the rail first increases and then decreases with the increase of the speed of the sprayer.Compared with low speed and high speed,when the speed is medium speed,the maximum deflection appears at the mid-span of the suspension rail.The maximum deflection is 83.14 mm when the suspension rail is 6 meters and 37.63 mm when the suspension rail is 4 meters.(4)Vibration test and damping design of sprayer system under working conditionsThe three-way acceleration sensor is used to measure the motion acceleration at different measuring points of the sprayer and the hanger rail.The DH5902 dynamic signal analysis system is used to obtain the time domain response and frequency domain response.The test results show that the acceleration values in three directions at high speed are significantly higher than those at low speed when the sprayer is running on the rail at half load.At high and low speed,the acceleration values in X and Z directions are obviously greater than that in Y direction;The vibration of the two measuring points on the rail and the measuring points at the support plate of the sprayer has regularity in the vertical direction,and the first-order natural frequencies are very close.Based on this,the corresponding vibration reduction design is carried out.The vibration reduction efficiency of the three measuring points on the main excitation frequency after vibration reduction is 66.9%~75%,66.7%~69.6%,64.6%~65.1%,respectively,with obvious vibration reduction effect.