Design And Simulation Of Robotic Mobile Platformfor Kiwi Fruit Harvesting Robot

China has the largest kiwifruit growing area in the world. It needs to invest a lot of labor in the kiwi picking. Therefore, it has very far-reaching significance to study the automatic picking kiwi technology which can be used to improve productivity, reduce farmers’ burden and to achieve the industrialization of kiwifruit growing. At present, there are some results of the kiwi fruit identification and damage mechanics research. Besides, the methods of extracting kiwi from complex background, as well as non-destructive harvesting and picking arm and end effector has been developed successfully. Therefore, the study of mobile platform which can move in orchards and allow the picking arm and end effector to achieve a wide range of picking scope has practical significance.In this paper, under the conditions of standardized kiwi planting pattern, It designed and studied on kiwi picking robot mobile platform. The main contents are follows:The working conditions of Kiwifruit picking robot mobile platform was illustrated and determined a preliminary program of the mobile platform. At beginning, we surveyed the scaffolding patterns, characteristics, topography and environmental conditions of the field.The mechanical relationship between the platform wheels and the ground was discussed. And then, the basic functions and the main designing parameters of the platform were determined according to the working conditions. Finally, a brief description of prototype first generation mobile platform was given and mainly focused on the overall design of the main structure and working principle of the second-generation mobile platform.Design and choose the main parts and modules of the mobile platform based on the working conditions and requirements. First, through the analysis of the tire ground mechanics,we determined the rotational torque value which allow mobile platform to travel and selected proper wheel motors, designing steering torque mechanical amplification mechanism.Secondly, the level adjustment mechanism of the platform was designed and presented. A rational geometric model was established to analyze the relationship between the height and adjustment features angle. And then, the mechanical analysis to adjustment mechanism found the load parts. The ANSYS was used to do statics simulate to determine a reasonable design parameters of the risk parts. Finally, three-dimensional design model and the overall assemblyof the entire platform have done in PROE.The thesis also simulated and analyzed the kinematics and dynamics models of the four-wheel independent steering mobile platform. First, on the basis of Akermann kinematic model, we analyzed the relationship between the turning angles of each tire and simulated the variations of turning angles which is vary with the variables of turning radius and turning input angle. Based on the turning relations on the basis of Akermann kinematic model, A four-wheel independent steering system each wheel rotation angle calculation graphical user interface was developed. Then, The main expressions of dynamic quantities,such as a tire lateral force, slip angle, longitudinal acceleration and lateral acceleration, were deduced.Finally, according to the dynamic differential equation of the mobile platform and using the MATLAB / Simulink as a tool, we build the dynamic simulation modules. Besides, combined with MATLAB / GUI, we established a mobile platform dynamics simulation graphical user interface, which make it convenient to optimize parameter of mobile platform. Using the developed dynamic simulation GUI, we simulated and analyzed the dynamic behavior of mobile platform, by observing the responses of the platform roll angle, yaw rate and lateral speed.Based on the prototype simulated and analyzed the influence of the centroid height changes posed on platform’s stability. First, the mechanical parameter such as centroid height was obtained. Combined with the former simulation method, by changing the height of the center of mass, analyzing the steering stability of prototype. Then compare the simulation results of the second generation platform and the prototype under the same conditions.