Research On Design And Optimization Of The New Rotary Hydraulic Self-servo Joint

Hydraulic robot joints are the basic components of hydraulic robot, whoseperformance have a direct impact on the overall performance of hydraulic robot.Hydraulic rotary self-servo technology which used small size and small torque motor tocontrol large output torque angle by hydraulic servo mechanism combines hydraulicservo technology with motor control technology. This technology which has beensuccessfully used in hydraulic robot joints can reduce the size of the hydraulic jointsand implement oil channel built-in. According to the current problems and deficienciesof the hydraulic rotary self-servo technology, a new type of the rotary hydraulicself-servo joint was designed. The structure of the joint was optimized, and the joint’srelative characteristics were researched. These work will make due contributions topromote the development and application of hydraulic robots. The main work andconclusions of this dissertation are as follows:（1）Designed a new type of rotary hydraulic self-servo joint, and gave the maintechnical parameters and performance indicators of the joint.（2）Established the dynamic model and system simulation model of the joint, andoptimized the structure of the joint by genetic algorithm, the optimization parameters ofjoint’s working chamber were achieved. Dynamic simulation and characteristic analysiswere carried out based on the optimized joint, the results showed that the optimizedjoint had better follow performance and greater output torque.（3）The dynamic numerical simulation of internal flow field in the optimized jointwas conducted by the dynamic mesh model and UDF technology, and the instantaneousvariation law of the pressure, flow rate, and leaves’ force of its internal flow field wereanalyzed. And some important factors which affected the dynamic responsecharacteristies of the joint were discussed.（4）The simulation analysis of internal annular gap flow between spool and valvesleeve in the optimized joint was conducted by Fluent software. The relationshipbetween gap film thickness and the amount of leakage was obtained, and therelationship between gap film thickness and viscous friction torque was obtained. Finally, the optimal value of the film thickness was gotten.（5）The finite element model of the body and cylinder in the optimized joint wereestablished, and the static and dynamic analysis of them were conducted by the finiteelement method.And obtained the distribution of stresses and displacements in the joint,and got the natural frequencies and mode shapes of the body and cylinder, whichprovided a theoretical basis for optimized design and experiment of the joint.