Side-grab Method Of Container Cargo For Intelligent Loading And Unloading Robot

The Intelligent mobile robot for loading and unloading operation is used for loading and unloading of carton goods instead of manual work.The box goods commonly are densely stacked,which can only be fetched by side adsorption,but vacuum adsorption for side grabbing has the problem of low reliability.The side grabbing method with high-reliability is one of the key technologies in the mobile robot,on which is focused in this thesis.The main research work and conclusions are as follows.The scene and requirement for loading and unloading are described and explained in this thesis.Mechanical analysis and simulation analysis are carried out on grabbing the carton goods by side with vacuum.By simplifying the corrugated board into layers and boards,the finite element model of corrugated board under the action of plane stress is established,and the dangerous section of corrugated carton under cantilever condition is analyzed by finite element method.The analysis results show that the corrugated carton has the risk of breakage under the long-term cantilever working condition which verifies that the method of side adsorption carton goods only with vacuum can’t meet the requirement of loading and unloading.The stability conditions of side adsorption with vacuum are studied and analyzed.By establishing the dynamic model of side grabbing,the effect of acceleration of goods movement on the minimum vacuum required for stability is obtained.Furthermore,by establishing the response model of vacuum adsorption system,the specific numerical relationship between vacuum degree and contact clearance height is obtained.The relationship between clearance height,contact force and rubber hardness is obtained by Abaqus simulation.Finally,the relationship between side adsorption stability and motion acceleration,operating time,vacuum response of system is obtained.Based on the above analysis on the stability of side adsorption,a new grasping method based on the combination of side adsorption with vacuum and bottom conveying is proposed.The side adsorption with vacuum provides the initial small displacement of the goods,and the bottom conveying completes the remaining large displacement of the goods.The dynamic model of the goods grabbed in this process is established,and the key parameters such as vacuum degree,motion time and motion acceleration in the side adsorption phase are calculated.The kinematic model of the manipulator is established,and the relationship between the acceleration of the end grabbing mechanism and the joint variables is deduced.The structural parameters of the manipulator and the grasping mechanism for loading and unloading are calculated and analyzed by modules,and the structures are designed in detail.The side grabbing method proposed in this thesis solves the problem of weak adaptability and low stability in the field of automatic loading and unloading at home and abroad,which is also applicable to other vacuum transportation scenarios.