Structural Parameter Optimization And Dynamic Performance Test Of The Hydraulic Rotary Vane Actuator

The basic working principle of the rotary vane actuator,generally referred to as RVA,is to use hydraulic pressure to push the rotating vane in the closed oil chamber,thus realising the conversion of hydraulic pressure into torque output.As a driving device,the RVA has the advantages of good controllability,smooth output torque,high mechanical efficiency and tight mechanical structure.When it is used in heavy duty applications,the smooth dynamic performance of the RVA output becomes particularly important.The key structural parameters involved need to be optimised in order to achieve further functions such as low starting oil pressure,high pressure resistance with good sealing properties and a stable output torque.Therefore,this paper focuses on the optimisation of the key structural parameters of the pendulum cylinder and its dynamic performance in combination with each other,mainly carrying out the following work.(1)A detailed analysis of the sealing mechanism of the RVA is developed and mathematical modeling of the starting pressure is carried out in conjunction with the analysis.Firstly,the axial pre-compression of the face seal and the rounded edge pre-compression of the blade seal block are modelled mathematically respectively,and the strain and stress in the seal contact are derived using the relevant elastodynamic theory.Then,the strain and stress distribution changes of the seal contact are deduced by combining the elastic modulus corresponding to different pre-compression amounts.Finally,the start-up pressure of the RVA is mathematically modelled and the variation of the start-up pressure of the face seal and the vane seal under different pre-compression amounts is shown.The aim is to provide a better in-depth analysis of the correlation between the structural parameters of the RVA seal and its dynamic performance.(2)In order to improve the stability and reliability of the dynamic performance of the RVA,the key structural parameters are analysed using the instability caused by vibration during operation as the starting point.Amongst other things,the friction generated by the seal contact in the RVA during relative movement is often the cause of vibration,involving important structural parameters such as the coefficient of friction and the pre-compression of the seal members.In addition,the speed of the RVA and the radius of the transition arc of the coupling surface of the rigid seal contact can also lead to crawling and low frequency chattering.For this reason,the complex eigenvalues of the RVA system are solved using the complex eigenvalue analysis method,combining important parameters such as friction coefficient,pre-compression,rotational speed and transition radius.Based on whether the value of the real part of the complex eigenvalue is positive or not,the instability of the RVA is determined and the relevant important parameters are optimized to improve the stability and reliability of the operation of the RVA.(3)Analysis of the dynamic output angular velocity of the RVA.Combined with the above-mentioned optimisation results for the relevant structural parameters of the RVA,the most direct effect can be seen in the angular velocity variation curve of the RVA during dynamic operation.Firstly,the flow equation,the flow continuity equation and the dynamic moment balance equation for the control valve of the RVA are used to derive the dynamic characteristic transfer function of the RVA.Then,the SIMULINK module in MATLAB is used to simulate its dynamic characteristics.Finally,the influence of different structural parameters on the dynamic performance of the RVA is analyzed,and the relevant structural parameters are further optimized.(4)Experimental verification of the feasibility and accuracy of the above theoretical analysis.Firstly,using the axial pre-compression of the end seal ring as a variable,the start-up pressure of the RVA was tested and recorded to verify the theoretical analysis of the start-up pressure of the RVA.Then,using the spool displacement of the flow control valve and the axial pre-compression of the face seal ring as variables,the change in the rotational angular velocity of the RVA was tested and recorded to verify the accuracy of the theoretical analysis of the dynamic performance of the RVA.Finally,the combination of experimental results and theoretical analysis to determine the value of the relevant structural parameters.