| In the whole logistics warehousing industry,stacker is the core handling equipment of intelligent three-dimensional warehouse.Performance of the stacker affects the whole logistics system greatly,and directly determines the access efficiency and cost.At present,the stacker industry is developing rapidly.In order to make full use of the storage space,the column height is becoming higher and higher,the running speed is getting faster and faster.The stacker with the traditional motion control algorithm will lead to the column amplitude is getting larger than before,and this will greatly affect the motion stability and efficiency,reduce the life of the stacker.Therefore,the stacker which can respond to the operation instructions quickly is in urgent need,which can not only reach the specified running speed and reduce the start time quickly,but also maintain stability at highly moving speed and reduce the flexible impulse.The research of motion control algorithm of high stacker is meaningful and useful.The main research work of this thesis is as follows:(1)Firstly,the structural stress diagram of the stacker is established,and then the mechanics analysis of the structural on the column is carried out.The vibration equation of the free end of the column of the stacker is finally derived.The analysis shows that the column amplitude of the stacker is related to the horizontal acceleration,the vertical acceleration and the horizontal speed of the stacker.At the same time,the acceleration rate —— jerk determines the sudden impact of instantaneous amplitude.These main influencing factors which are considered when studying the column vibration of stacker will provide theoretical basis for the subsequent algorithm design.(2)The structural scheme of the double-column stacker is researched and the threedimensional models are constructed by using Solid Works,and the static analysis and modal analysis of the stacker frame and fork model of the loading platform are carried out by using Ansys.The simulation results were verified and optimized with the relevant data of the design safety manual,and then the rationality of the design scheme was checked.The virtual prototype of the double column stacker is built by using multibody dynamics software Adamto simulate the real movement process of the stacker to access goods.The dynamic simulation analysis is carried out to verify the reasonableness of the design scheme of the stacker According to the simulation force and motion characteristics of the stacker virtual prototype,it can provide a reliable basis for the subsequent relevant optimization design and short the design periods.(3)In order to improve the operation stability of the stacker and to solve the sudden impact problem of the traditional S-curve acceleration and deceleration control algorithm which affects the instantaneous amplitude of the stacker column due to the discontinuous jerk,a new acceleration and deceleration control algorithm of the Positive Vector Square(PVS)curve is proposed in this thesis.By deducing the vibration equation of the column structure of the stacker,the velocity algorithm model with the PVS function as the core is constructed,and the Simulink vibration simulation model is built.All the velocity,acceleration and jerk curves of the PVS acceleration and deceleration control algorithm are continuous.After that,the new proposed algorithm and the traditional Scurve acceleration and deceleration control algorithm are substited into the Simulink vibration model for comparison and simulation,and then the amplitude results of the column were analyzed.The results show that the acceleration and deceleration control algorithm of the Positive Vector Square(PVS)curve can suppress the swing amplitude of the column effectly.The stacker based on this propesed algorithm can not only take into account the stability,but also reduce the amplitude of the column.The control result is better than that of the other algorithms. |
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