| ·With planting area of tomatoes and chilies in Xinjiang growing,the demand for plug seedlings automatic transplanter is increasing.The plastic film mulching transplanting work in Xinjiang basically relies on manual operation,some semi-automatic machines included,that labor is short in transplanting period.The picking-up technology for plug seedling is the key to automatic transplanter,and it is of great significance to develop an efficient and low damage automatic picking-up seedling mechanism for reducing labor intensity and emancipating the productive forces.At present,the research on the automatic transplanter for plug seedling in China is mostly in the experimental stage and there is still a large gap compared with developed countries especially in dry land transplantation.In this paper,an automatic picking seedling transplanting mechanism of acupoint planter was designed,and its structure and control system were studied.(1)In view of the design requirements of the whole row automatic picking seedling mechanism,the overall design scheme of the picking seedling transplanting device of the seedling transplanter was put forward and its working principle was analyzed.In this paper,the whole row of seedling manipulator,the whole row of picking seedling locating mechanism,the offering seedling mechanism and the dividing seedling mechanism were designed,respectively,and the parameters of the end-effector rod of the whole row of seedling manipulator were optimized.Based on VB's human-computer interaction optimization interface was designed and developed,and optimized objective function was established with target of centre-to-centre distance of the seedling needle,the key parameters were obtained in the MATLAB environment.In this paper,a set of mechanism parameters which met the requirements of automatic picking seedling of tomato acupoints were obtained.The 3d model was established based on the optimized bar parameters,and then the 3d model was imported to ADAMS to verify its seedling trajectory.The motion was in line with the expectation,and the simulation analysis was basically consistent with the theoretical analysis.This paper analyzed the law of lifting motion,and drived the lifting motion with the first order function motion law,and obtained the seedling trajectory coordinating with the clamping track.(2)Based on the structure characteristics of the automatic seedling mechanism,the control requirements of the whole row of seedling location control and the whole row of seedling control were analyzed,and the control scheme was designed respectively.For the whole row of seedling location control,the impact of the accumulated error in the process of movement to the positioning accuracy is bigger,horizontal positioning control has great influence on the success rate of seedling,accuracy of lifting and positioning control has bigger influence on the injury rate.The automatic seedling mechanism works in the field environment,and has higher requirements on system stability.According to gripping control requirements of the row type seedling hands,the cylinder was chosen as the original power,and 4*4 scheme was adopted to group the cylinders,two 5-pass solenoid valves were used to control the cylinder,and the pneumatic transmission circuit was designed.The stepping motor was selected as the dynamic element of the positioning movement,the external positioning of the open-loop control to complete the positioning control of the stepping motor was adopted by the lifting motion control,horizontal positioning adopted closed loop control with position calibration.Horizontal positioning control and lifting positioning control simultaneously selected the way of increasing the external positioning link,and the reciprocating motion process was calibrated several times,which greatly reduced the influence of accumulated error.(3)In view of the importance of the horizontal motion positioning of the whole row of seedling mechanism in the whole control system of the seedling mechanism,an adaptive fuzzy PID control scheme was proposed for the control of this part.The mathematical model of the horizontal positioning closed-loop control system was constructed,the fuzzy control rules were analyzed and formulated,and the adaptive fuzzy controller was designed.In MATLAB,simulink control box was called to complete the PID control model and fuzzy PID control model of the horizontal positioning control system of the automatic seedling mechanism,adjusting KP,KI,KD parameters with standard step signal as input signal,and then the output response under PID control was obtained.The corresponding comparison can be obtained compared with adaptive fuzzy PID control,adaptive fuzzy PID control model made the whole row automatic seedling mechanism more stable in horizontal positioning control.After the disturbance,the stable state can be recovered more quickly,and there's no overtones.The adaptability of the positioning control of transplanting machine in the field was better,and it provided the theoretical guidance for the seedling mechanism to adapt to the complicated and changeable fieldwork environment.(4)The hardware design and software program development of the control system of the automatic seedling control system.With PLC as the controller,selection of components and allocation of PLC pin were carried out,and hardware connection was designed.The software program of the control system of the seedling mechanism was developed.In GXworks2 integrated development environment,step ladder diagram was adopted to develop software,and the process flow chart of each part was designed.The realization of fuzzy PID algorithm was realized by calling the special PID instruction of mitsubishi PLC.In the design environment of GTWORKS3 interface,the man-machine interaction interface of the control system of the whole row automatic seedling control system was designed,and the overall system design was reliable.The whole row automatic seedling mechanism test bed was set up and the bench test was conducted.The whole row of seedling manipulator can complete the seedling movement according to the predetermined process,and the positioning was more accurate,which greatly improved the seedling efficiency,and the overall operation of the mechanism was stable. |
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