Semi-active suspensions have drawn particular attention due to their superior performance over the other types of suspensions. One of their advantages is that their damping coefficient can be controlled without the need for any external source of power. In this study, a handful of control approaches are implemented on a car models using MATLAB/Simulink. The investigated control methodologies are skyhook, groundhook, hybrid skyhook-groundhook, Acceleration Driven Damper, Power Driven Damper, H∞ Robust Control, Fuzzy Logic Controller, and Inverse ANFIS. H∞ Robust Control is an advanced method that guarantees transient performance and rejects external disturbances. It is shown that H∞ with the proposed modification, has the best performance although its relatively high cost of computation could be potentially considered as a drawback. Also, the proposed Inverse ANFIS controller uses the power of fuzzy systems along with neural networks to help improve vehicle ride metrics significantly.
In this study, a novel approach is introduced to analyze and fine-tune semi-active suspension control algorithms. In some cases, such as military trucks moving on off-road terrains, it is critical to keep the vehicle ride quality in an acceptable range. Semi-active suspensions are used to have more control over the ride metrics compared to passive suspensions and also, be more cost-effective compared to active suspensions. The proposed methodology will investigate the skyhook-groundhook hybrid controller. This is accomplished by conducting sensitivity analysis of the controller performance to varying vehicle/road parameters. This approach utilizes sensitivity analysis and one-at-a-time methodology to find and reach the optimum point of vehicle suspensions. Furthermore, real-time tuning of the mentioned controller will be studied. The online tuning will help keep the ride quality of the vehicle close to its optimum point while the vehicle parameters are changing. A quarter-car model is used for all simulations and analyses. / Ph. D. / Passenger safety and comfort have always been two major concerns in designing and engineering vehicles. Suspensions play a vital role in this regard. They are there to ensure a very smooth and comfortable ride experience. Many technologies have been developed to increase performance of suspension and customize their functionality. However, only a few developments led to a new family of suspensions and opened a broad field in automotive engineering for researchers to do their twist and tweaks. One fascinating technology that was developed a few decades ago, was semi-active suspensions. Their advantage over conventional ones is that its stiffness can be adjusted on the fly. This property can be combined with a control methodology in order to improve the ride experience further more compared to conventional suspensions.
In this dissertation, some novel control methodologies are developed and compared with existing ones. The results are discussed exclusively for each controller.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/73445 |
| Date | 14 November 2016 |
| Creators | Ghasemalizadeh, Omid |
| Contributors | Mechanical Engineering, Taheri, Saied, Roan, Michael J., Ahmadian, Mehdi, Singh, Amandeep, Sandu, Corina |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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