Walking Control Technology And Equipment For Greenhouse Operation Vehicle

Nowadays,agricultural robots are widely used in material transport and information collection in greenhouse.With the development of domestic and aboard researches on agricultural vehicle navigation,the agricultural vehicle navigation based on the greenhouse non-structural characteristics become one of key technologies.According to the characteristics of narrow space between ridges in our country's greenhouse,a magnetic guide type of collaborative vehicle control system and equipment which used magnetic navigation between greenhouse ridges was designed.Fuzzy PID path tracking algorithm was applied to improve the navigation accuracy.The simulation analysis was conducted by MATLAB/Simulink.Besides,the weighted fusion algorithm was used to improve the measurement accuracy of the ranging module to make the accurate tracking of the vehicle.In order to verify the feasibility of the control system,this paper designed and developed the hardware of the control system of the magnetic guided vehicle.Combined with the design and debugging of software system,the experiment was carried out between greenhouse ridges.The main contents of this paper are as follows:(1)According to the performance index of walking mechanism for greenhouse operation vehicle,the crawler type walking mechanism was served to implement automatic navigation of the vehicle in the greenhouse.According to the greenhouse operation vehicle steering control problem,the proposed control system of Tracked Vehicle Based on greenhouse habitat information collection,according to the characteristics of magnetic navigation sensor is established as the state variable operating vehicle left and right wheel differential steering motion model based on the path of lateral deviation and lateral deviation change rate.(2)According to the design requirements of magnetic type greenhouse tracked vehicle collaboration and designated cruise function,the vehicle control system of the main structure are introduced,and the main controller,a control system of the magnetic navigation module,location module,positioning module,drive module,power supply module selection and circuit design.The main controller module and sensor module are analyzed and described in detail.The design of STC15W4K56S4 MCU minimum system circuit,including power circuit,clock circuit and reset circuit.Due to the unstable state of the control system or the program deviation in the running process,the external control circuit is used to restore the working state of the control system manually.16 Holzer sensors are used to detect the whole column,and the stability of navigation information detection is improved.On the basis of the hardware design of the walking control system,the software of the walking control system is constructed,which can coordinate the running of each function module.For each function module realization process given magnetic type greenhouse operation vehicle control system software architecture,using C language to program in the Keil Vision4 compiler development environment selection.(3)The design and Simulation of the walking control system of greenhouse operation vehicle.Weighted fusion algorithm is used to fuse the measured values of different sensors.By using the fuzzy PID algorithm as the vehicle navigation algorithm,according to the motion model of walking system for greenhouse vehicles,vehicle path tracking simulation system based on MATLAB/Simulink platform,results show that the control system can walk according to the deviation signal within 0.5 s driving signal producing students stable;when the spike pulse signal into system to reach the steady state system,to restore stability in the 0.5 s,verify the feasibility and effectiveness of the algorithm.(4)A navigation experiment was carried out in the greenhouse of the Jiangsu University,which was based on the crawler greenhouse information collection vehicle.The test results show that the ground between the ridges in the greenhouse,when the vehicle speed is 1m/s,the man-machine operation vehicle following distance error is less than 5cm;when the vehicle speed is 0.4-1m/s,fixed cruise parking vehicles after the center and set the habitat information monitoring points of the distance is less than 0.3cm;when the operation of the vehicle speed is 1 m/s when the 5m line segment transverse navigation error is less than 2.6 cm;when the vehicle is in the greenhouse for Longtou to the radius of circular curve path following 0.75 m operation,the vehicle speed is less than 0.3m/s,the maximum lateral deviation of 2.2 cm.The experimental results show that the control algorithm has good robustness and real-time performance.