The Development Of Classifier For Small Jujubes Based On Electromagnetic Synchronous Actuator

In order to improve the grading accuracy and speed of jujube classifier,the third generation of jujube grading machine is developed on the basis of the second generation of(pneumatic)jujube sorting machine.The third generation of jujube grading machine use size,shape,color and other external comprehensive characters as grading standards for the rapid automatic non-destructive testing of jujube grading.In this paper,the jujube classifier based on electromagnetic synchronous actuator is designed.The whole machine is composed of roller conveyor chain,dialing chain,electromagnet,synchronous transmission sprocket,STM32F407 image processor and STM32F103 coprocessor for the controlling execution of the actions.The grading unit is synchronized with the roller conveyor,and the highly sensitive electromagnet is used to absorb the switch of the pinch plate and perform the action.The research works in this paper mainly focus on the following aspects:1.The integrated design of the actuator of the third generation of jujube grading machine.In this chapter,it mainly describes the operating principle of the whole equipment,and focuses on the working principle of the grading actuator.The structure unit of the grading actuator is determined,and each part of the actuator is briefly introduced,mainly including the synchronization mechanism,the base plate,the dial plate,the buckle plate,the tension spring,the electromagnet resetting device and the switch protection.2.The study of the cooperation between the grading actuators.By experimenting,the axle is adopted to link the bottom plate,the dial plate and the buckle plate.The sizes of the bottom plate,the dial plate and the buckle plate are determined after calculation.Based on the hysteresis loop,magnetic material in the buckle plate should be the silicon steel sheet.The dial spacing device is designed(angle and size).The shape of the hanging spring device is designed like a horn.The length of the spring is determined.3.The selection of the electromagnet and the determination of its install location.The external dimension and the physical parameters of the electromagnet are determined by theoretical calculation and experiment.The install position of the electromagnet is determined by calculation.The DC electromagnet with advantages of high stability,strong magnetic absorption and little magnetic remanence is adopted.4.The design of the resetting device and switch protection.During the test,it is found that the effect of the rigid resetting device is poor and the damage is caused to the dial plate.Therefore,the resetting wheel is designed,which has obvious effect that it avoids the damage caused by the rigid resetting device.The edge of the resetting wheel is designed as involute of a circle,for the movement track of the working dial plate is involute of a circle.In order to prevent the damage from the dial plate that can not be properly returned,the switch protection is designed.5.The test of the reliability and grading speed of the device.The speed of image processing is 50ms/frame.The time of the actuator action is 40ms.The roller conveying speed is 320mm/s.The jujube grading speed is 20 jujubes/s.It can realize three grading levels of the size of red jujubes and one grading level of green ones.The accuracy rate of grading is 93.7%.The lossless rate is 100%.The maximum capacity is 1000kg/h,which is twice as fast as that of the second generation jujube grading machine.The fatigue experiment of the prototype shows that the prototype has reached the original design goals.