| With the in-depth implementation of China’s Rural Revitalization Strategy,lotus seed industry as a new rural regional characteristic industry has developed rapidly.However,fresh lotus seed dehulling is still manual operation,which is difficult to meet the timeliness requirements of fresh lotus seed processing,and has become a bottleneck problem restricting the large-scale development of lotus seed industry in China.In order to realize the mechanization and automation of fresh lotus seed coring,this paper adopts the method of air extrusion coring,and develops the corresponding pneumatic and control system based on the timing requirements of each mechanical action of fresh lotus seed coring.In this system,the color code sensor is used to identify the fresh lotus seeds,the hollow punching needle is used to insert the lotus seeds and the compressed air is used to extrude the lotus seeds,and the MCU is used to automatically control the feeding,straightening,end identification,clamping,coring and discharging of the fresh lotus seeds,so as to realize the efficient processing of fresh lotus seeds.The main contents of this paper are as follows1.Analysis of control object and control requirement.The working principle of fresh lotus seed coring was analyzed,and the structure and function of the main components of the automatic fresh lotus seed coring machine were analyzed.Based on the working principle of fresh lotus seed coring machine,the working process of fresh lotus seed coring process was analyzed,and the design requirements of control system were put forward according to the working environment and use requirements of fresh lotus seed coring machine.2.The design of pneumatic system of fresh lotus seed coring machine.Based on the characteristics of quick response and flexible control of pneumatic control,compressed air is used as the power source for the mechanical actions such as stirring,sorting,clamping,needle insertion and coring in the process of coring.The pneumatic system of fresh lotus seed coring machine is designed,and the main pneumatic components in the system are calculated and selected.3.The control system design of fresh lotus seed decanter.Based on the time sequence requirements of the fresh lotus seed coring machine,the control scheme of fresh lotus seed coring machine system was designed;Through the analysis of the control object,the MCU hardware system based on pic18f87k22 is designed;At the same time,the selection of main electrical control components such as stepper motor,touch screen,color code sensor and photoelectric switch is completed;The control circuit schematic diagram of fresh lotus seed decanter was designed,and the system control program was compiled,and the human-computer interaction interface of the control system was developed.4.Chain motion control curve design.In order to shorten the moving time of the chain and improve the working efficiency,and avoid the mechanical impact of the chain caused by the rapid starting process in the intermittent movement,a chain motion control curve based on the continuous jump asymmetric modified trapezoidal motion law was proposed.When the chain pitch was 38.1 mm and the moving time of the chain was t=240 ms,The maximum forward acceleration amd=2.508 m/s2,the maximum reverse acceleration ama=3.923 m/s2,which ensures the fast and stable operation of the chain.5.On line test of control system.The experimental results show that the intermittent movement of the chain is stable,the timing sequence of each mechanical action is consistent with the fresh lotus seed heart removal process,and the operation of the system is stable;The test results show that the average comprehensive success rate of fresh lotus seed decanter is 96.07%,the damage rate of lotus seed is only1.47%,the integrity rate of lotus seed is 88.67%,the working rhythm is 0.54 seconds,the test prototype is two stations,the production efficiency is 0.27s/piece,about 7-8skilled workers,the production efficiency meets the design requirements.At present,the fresh lotus seed processor with this control system has completed the technology transfer and entered the mass production stage. |
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