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Design And Control Of A Wire-Driven Parallel Working Platform For Outside Wall Cleaning

Posted on:2013-05-09Degree:MasterType:Thesis
Country:ChinaCandidate:X L JiangFull Text:PDF
GTID:2248330392950608Subject:Mechanical engineering
Abstract/Summary:PDF Full Text Request
Three main methods for outside wall cleaning are used in recent years, including"spider-man", railway glass rubbing machine and climbing cleaning robot. Forshortcomings of the methods, a new way, applying wire driven parallel technology toa working platform, with high safety factor, low cost, low labor intensity but highefficiency is proposed. By actuating cables, the platform can move from one locationto a cleaning point quickly and safely. While workers are cleaning, it can also moveslowly to ensure that they can have enough time finishing the task.In low speed case, the inverse kinematic, workspace analysis, static stiffnessanalysis, prototype building and testing are analyzed. Inferences of the sizes on theworkspace are also analyzed, which results in selecting initial sizes of the mechanism.First, from the point of view of decreasing interferences between wires andsaving cost, URPM4-3R3T which can only control the working platform in threetranslational dimensions steadily is selected. Without influencing the wire lengthcalculating precision, the catenary model is simplified to be Pseudo-Curve model.Based on the model simplification, the inverse kinematic and the statics are analyzedto formulate the wire tensions.Based on a tension constraint optimization algorithm, workspaces of themechanism with different mechanism sizes on the main working planar surface areobtained.Least Square-Support Vector Machine (LS-SVM), a global optimization method,is adopted to enhance the static stiffness. Deducing the incremental expression of thestatic stiffness matrix theoretically, stiffness matrix of a point in the workspace is alsoreported. Using LS-SVM to fit discrete points of stiffness matrix into surface, thestiffness distribution is depicted on the main working planar surface. In order toincrease the weakest stiffness, optional mechanism sizes are optimized again. In thisway, the optimized mechanism size is finally determined.At last, according to the defined size, a1:10prototype is built. It is tested to complete the communication between its hardware and software, and finish thescheduled work trajectory by position control method. The experiment not onlyverifies the correctness of theoretical analysis and motion simulation, but also lays afoundation for the latter to carry out the dynamic analysis and control of themechanism.
Keywords/Search Tags:Wire-Driven, Under-Restrained Parallel, Manipulator, Pseudo-Curvemodel, Least Square-Support Vector Machine, Kinematic Level Control
PDF Full Text Request
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