| Hydro-pneumatic suspension can be divided into separate hydro-pneumatic suspension and inter-connected hydro-pneumatic suspension based on the suspension cylinders connected or not. For the connected hydro-pneumatic suspension, the suspension cylinders are inter-connected with oil pipes and kinds of valves, which can make the load evenly distributed among the suspension cylinders, that is why connected hydro-pneumatic suspensions are popular used among engineering vehicle, limousine and military vehicle.At present, it is rarely research about connected hydro-pneumatic suspension, and only a little theoretical study and simulation analysis focused on the special vehicle in the domestic. In this paper, based on the analysis of connected hydro-pneumatic characteristics, it is proposed one semi-active control system for connected hydro-pneumatic suspension and has done following research work.(1) The simulation model of connected hydro-pneumatic suspension is built in this paper with the software AMESim. And with simulation, it is analyzed the static and dynamic properties of connected hydro-pneumatic. Moreover, it is analyzed the influences of orifice size, accumulator volume and the pre-charged pressure of accumulator on the characteristics of connected hydro-pneumatic suspension in details.(2) The nonlinear mathematic model of connected hydro-pneumatic suspension is built, and based on differential geometry theory, the nonlinear system of connected hydro-pneumatic suspension is transformed to a linear one. What’s more, it is realized the decoupling and inverter between the control variables and system outputs, which makes the transition from complex nonlinear semi-active hydro-pneumatic suspension mathematic model to an exact linear mathematic model.(3) For the exact linear system of semi-active hydro-pneumatic suspension, it is designed the LQR controller. And with software Matlab/Simulink, it is analyzed the control system for the exact linear suspension model and compared with the passive connected suspension.(4) The co-simulation model of semi-active connected hydro-pneumatic suspension is built with software AMESim and Simulink. It is designed feedback exact linearization and PID control system and LQR control system respectively for the semi-active connected hydro-pneumatic suspension. From the results of AMESim/Simulink co-simulation and the analysis of the data, it is proved that both the PID control system and LQR control system improve the connected hydro-pneumatic suspension vibration performance obviously, compared with the passive connected hydro-pneumatic suspension.In this paper, with theoretical derivation, it is realized the transition from complex nonlinear semi-active hydro-pneumatic suspension mathematic model to an exact linear mathematic model. Based on feedback exact linearization, it is designed PID control system and LQR control system for semi-active connected hydro-pneumatic suspension, which will provide much theory basis for the semi-active control of connected hydro-pneumatic suspension and have much theoretical value and practical application significance. |
PDF Full Text Request