Develop a model for the Hydraulic Active Suspension system to investigate the performance of the system (Quarter Car Method)

Author: Kushagra Mandwal

Mandwal, Kushagra, 2020 Develop a model for the Hydraulic Active Suspension system to investigate the performance of the system (Quarter Car Method), Flinders University, College of Science and Engineering

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The continuous technical progressions are necessary for every field to provide better quality and comfort to consumers. In this way, automotive industries are playing an important role. Where continuous inventions could be led by quality ride, vehicle safety improvements and provide luxury to customers. Also, the vibration is generated from the uneven condition of the road can cause injuries like fatigue, mental stress and back pain. To overcome these vertical forces and unevenness, the excellent suspension system is a necessary part of all vehicles. The investigation of vehicle performance regarding vehicle suspension and increase safety of the passengers, many lumped parameter models of the suspension system such as the quarter car, half car and full car model are in use. But this research is based on the quarter car model (Single tyre suspension). Also, there are many types of the suspension system are using in the vehicles: passive, semi-active and fully active suspension. But, get topmost results, active suspension system would be the best. The development of the full hydraulic active suspension system and its different part is the primary objective of this research. The developed model is based on the bond graph model technique. State-space equations are derived from the modelled bond graph. These equations are simulated with the help of MATLAB/Simulink software environment. For hydraulic unit following components: the reservoir, speed-controlled motor, positive displacement pump, accumulator, bypass or relief valve, four-way spool valve and hydraulic piston-cylinder arrangement has been modelled from the bond graph technique. For the suspension unit, the quarter car model of the suspension system has been used and modelled with the help of bond graph technique. In respect to the chapter of this thesis, introduction and background of the suspension is outlined in chapter one. The reviewed of the previous relevant researches are written in the second chapter. While the various suspension system and theory behind it are in chapter three. Bond graph modelling technique and its essential elements are described in chapter four. The fifth chapter is about the mathematical representation of the passive and active suspension system (on quarter car model). Also, the initial behaviour of these systems is in this chapter. The whole system model, mathematical equations and brief theory of different components are mentioned in chapter six. The derived state-space equations from the system bond graph have used to design the MATLAB/Simulink model has been described in chapter seven. The results and discussion of the simulated results are explained in chapter eight. The concluding remark has been formed, and possible future scopes are suggested in chapter nine. The results show that the hydraulic active suspension system could perform better and minimise the vertical acceleration and velocity better than the passive and semi-active suspension. But there are some minor errors in results that could be fixed with the use of the proper controller technique. Also, this work only for the left moving position of the direction control valve which could also be analysed for right moving position and controller could be used to get proper direction control in future works. Fundamentally, this research work provides the physics model platform that could help to control engineers to design proper control algorithm to get the desired output from this system.

Keywords: Quarter Car Suspension System, Mathematical Modeling, Active Suspension System, Hydraulic Active Suspension System, MATLAB, Simulink

Subject: Engineering thesis

Thesis type: Masters
Completed: 2020
School: College of Science and Engineering
Supervisor: Dr Amir Zanj