Research On Structure And Control Of Loading And Unloading Manipulator Based On Multichannel Machine

In recent years,with the rapid development of air-conditioner industry,it has also driven the prosperity of related spare and accessory parts market.Cylinders,flanges,etc.as key components of air-conditioner compressors have also entered a period of rapid development.At present,most of the cylinder and flange production lines in China are using manual loading and unloading production methods.There are some problems such as low automation,high labor costs,and unstable processing quality of parts,which greatly restrict the development of air-conditioner compressor manufacturers.With the increasing combination of industrial automation technology and loading and unloading technology,it is becoming more and more common for manipulators to undertake the task of loading and unloading in the field of automation,playing an important role in connecting different facility in series and improving production efficiency.This research project is to design manipulator of multichannel machine(cylinder,flange production line)for performing efficient and stable loading and unloading tasks,to achieve automated production of cylinders,flanges and other rotary parts.This research project firstly designed overall structure of the loading and unloading manipulator,including selection of overall structure type,determination of work procedure,design of mechanical structure,research of driving system,and so on.And the software,SolidWorks,was used for building 3D model of manipulator.Subsequently,the rigid multi-bodies model of manipulator was established by RecurDyn-SolidWorks platform.The meshing stiffness and contact stiffness were calculated based on Hertz theory for ensuring the accuracy of parameters.The modal flexible body of beam(RFlex)and node flexible body of sliding platform(FFlex)were set up by two different flexibility approaches,the rigid-flexible coupling multi-bodies dynamic model of the loading and unloading manipulator was built based on RecurDyn-ANSYS co-simulation platform at last,the rigid-flexible coupling model focuses on coupling effect between elastic deformation of key components and overall system motion,which is closer to the actual model of large,light,high speed and high precision mechanical system.And the dynamic characteristics of the loading and unloading manipulator were analyzed bysimulating actual running flow path.After simulation of dynamic characteristics the results of driving torque amplitude and motion velocity are obtained respectively,which not only show that the nominal torque of retarders selected by theoretical calculation meets requirements of the required torques,but also reveal that the running speed of machine meets the technical requirement of 60m/min,and the fluctuation of speed is small.Then the motion accuracy of manipulator is evaluated by measuring deviation between actual trajectory in rigid-flexible coupling model and ideal trajectory in rigid multi-bodies model,which shows that trajectory deviations in X and Z directions which are small can be neglected.While the trajectory deviations in Y direction is-0.72~+0.39 mm,which can evaluate that motion accuracy of manipulator is ±0.72 mm,the result don’t meet technical requirement of ± 0.2mm.And when manipulator is running at the end of beam the deviation amplitude of 0.4mm is greater than its 0.2mm in front of beam,in line with the engineering phenomenon that cantilever beam mainly generates up and down swing deformation so that the movement deviation of manipulator is under the influence.Meanwhile it also shows that the beam stiffness isn’t sufficient.In order to further diagnose the weak parts of overall structure,the modal analysis of structure system was carried out.The result shows that the vibration mode is dominated by the vibration of beam structure.It can be seen that beam as structural part has greatest influence on low-price vibration mode of the whole structure system.In order to enhance stiffness of beam and improve the performance of machine,the analysis method of multi-objective optimization is adopted to optimize the structural dimensions of beam,which acts as a key component of the loading and unloading manipulator.The cross-section dimensions,mass and static maximum deformation of beam are parameterized.A multi-objective optimization analysis model with constraints and objective functions is established.Not only the sensitivity analysis of the parameters for quality and static maximum deformation of beam but also the optimal analysis scheme can be obtained.Combing the engineering application,the cross beam structure needs to be redesigned.The beam structure with integral height of 155 mm,integral width of 150 mm,upper wall thickness of 20 mm and right wall thickness of 15 mm is adopted.The comparative analysis shows that the maximum deformation of theoptimized beam in static analysis is reduced by 74.9% compared with that before optimization,which further indicates that the stiffness of beam has been enhanced effectively.The rigid-flexible coupling multi-bodies dynamic analysis of the optimized manipulator system is carried out again,the result shows that the motion deviation of the end-effector in Y direction is-0.72~+0.39 mm,the motion deviation amplitude reduces77.5%.At last the optimized motion accuracy is evaluated to be ± 0.17 mm,which satisfies the technical requirement,which shows that the dynamic characteristics and operation performance of the manipulator are significantly improved after structural optimization.Then the physical prototype is built based on the optimized model.Finally,the control system is designed.The Inovance H3U-3232 MR is used as the core controller,and the Inovance IT60707 touch screen is configured as the upper computer,so the overall control platform is built in the way of “PLC+HMI”.The modular design method is used to complete the overall electrical design of the manipulator,and wiring and installation of the control cabinet are completed.The PLC program is programmed according to the loading and unloading work process,the multi-axis and multi-modes operation pattern of the manipulator is designed.And the user-centered human-machine interface with the functions of operation,monitoring and diagnosis is designed.Combined with the peripheral equipment(stock bin,multichannel machine,etc.),the manipulator runs and debugs in the industrial field,a large number of experimental results show that running speed and positionaI accuracy of the loading and unloading manipulator based on multichannel machine respectively meet technical requirements of 60m/min,± 0.2mm.It can meet the requirement of high speed,high precision,stable and reliable industrial application.