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Analysis And Design For Hexapod Robots With Parallel Mechanical Legs

Posted on:2016-09-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y RongFull Text:PDF
GTID:1108330479450982Subject:Mechanical Manufacturing and Automation
Abstract/Summary:PDF Full Text Request
At present, hexapod robot is one of the hot topics in the field of robot. The existing hexapod robots are generally designed with 6 serial mechanical legs on there trunks. Hexapod robots with this kind of structure are very thin and fragile to ensure that their structures are compact. Or their volumes are very large to ensure that they have great bearing capacity. In this paper, parallel mechanisms have been applied to the mechanical legs of hexapod robots, so deficiencies of serial mechanical legs can be improved. Parallel mechanical legs can make hexapod robots have great bearing capacities and movement flexibilities, and they also have compact structures. This can improve the environment adaptability and practicability of hexapod robots.The hexapod robot’s overall configuration has been analyzed in this paper, so the number and type of mechanical leg’s degree of freedom has been determined. Mechanical legs are divided into two classes: point contact and surface contact, based on the contact forms between foots and ground. The screw theory has been used for configuration analysis, 2-UPS+UP parallel mechanism was chosen as the initial mechanism,(U+UPR)P+UPS parallel mechanism was obtained as the final mechanism for the point contact mechanical leg by decoupling optimized. And then 3-UPS parallel mechanism was chosen as the initial mechanism, 2-UPS+UPU parallel mechanism was obtained as the final mechanism for the surface contact mechanical leg by decoupling optimized.The position negative solutions formulas of(U+UPR)P+UPS parallel mechanism have been established. The kinematics, statics and dynamics of(U+UPR)P+UPS parallel mechanism have been analyzed, and the mechanisms performances of(U+UPR)P+UPS parallel mechanism have been evaluated by defining the performance evaluation indexes. Relations between structural parameters and performance evaluation indexes have been revealed. An excellent set of structural parameters have been found by Monte Carlo method. A new kind of 3-DOF parallel mechanical leg has been designed based on(U+UPR)P+UPS parallel mechanism. The error model and sensitivity of(U+UPS)P+UPS parallel mechanism(it has the same topological structure with(U+UPR)P+UPS parallel mechanism) have been analyzed, considering the error tolerance and technological factors.The position negative solutions formulas of 2-UPS+UPU parallel mechanism have been established. The kinematics, statics and dynamics of 2-UPS+UPU parallel mechanism have been analyzed, and the mechanisms performances of 2-UPS+UPU parallel mechanism have been evaluated by defining the performance evaluation indexes. Relations between structural parameters and performance evaluation indexes have been revealed. An excellent set of structural parameters have been found by Monte Carlo method. A new kind of 5-DOF parallel mechanical leg has been designed based on 2-UPS+UPU parallel mechanism.The virtual prototype of a new kind of hexapod robot with decoupling structure has been designed based on the(U+UPS)P+UPS parallel mechanism leg. The instantaneous equivalent parallel mechanism of the hexapod robot with(U+UPS)P+UPS parallel mechanism legs was obtained, and its kinematics has been analyzed. The gait planning of the hexapod robot with(U+UPS)P+UPS parallel mechanism legs has been analyzed by double-triangle gait, and its motion simulation has been done. The curves of drive parameters have been obtained.A new kind of hexapod robot’s experimental prototype with 2-UPS+UP parallel mechanism legs has been designed. Considering the mechanical manufacturing process, the experimental prototype was manufactured. The concept of hexapod robot with parallel mechanism legs has been validated. These findings extend the application fields of hexapod robot.
Keywords/Search Tags:hexapod robot, parallel mechanical leg, decoupling mechanism, performance evaluation index, structural optimization design, experimental prototype
PDF Full Text Request
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