Wednesday, October 5, 2016

Design and simulation of Automobile active suspension system

INTRODUCTION: -

the suspension system in the car is provided to absorb the shocks in the vehicle and prevent any damage in the components of automobile by these shocks. It helps to make the ride comfortable to the occupant. It is an important mechanism to control the dynamic aspects of the automobile and make its control easy and stable.

In the mechanism of suspension system of a vehicle, the components efficiency of the vehicles is an important factor. Basically the mechanism is about keeping the car frame and car wheels apart from each other. For good suspension the dynamics control is necessary. For this purpose all the three movement i.e. pitching, rolling and yawing should be consideration while designing a suspension system. These three movements occur in the three axes of vehicle.

As in this project we want to design an active suspension system and then simulate it on a testing or simulation software, so we will study about the necessary parameters and information to design such system.

NEED OF THE PROJECT:-

 Now a days new technologies are coming day by day and the wold is moving very fast. New methods has been developed for suspension as well. But we are trying to get an efficient system which complies with almost all aspects related with economy and efficiency.

The most use method of suspension is called passive suspension. It can also be said as a conventional method of suspension. In the passive suspension the springs are used. The stiffness of spring and dumping are the parameters to be considered.

 Another method which is advance to this is active suspension method. But this method is quite expansive as it needs a separate energy source in the suspension system which makes it less economical. That is why we need a suspension system that have the properties of being efficient and economical at the same time.

 The semi active suspension system is able to fulfill these requirements. In the semi active suspension system properties of both passive suspension and active suspension system is utilized.

Process of performing the tests and reaching to a result of project-
·         This is a project about developing an active suspension system of an automobile.

·         In a car model two input parameters are considered i.e. damper rate and stiffness of spring.
·         For the study of nature of these parameters the experiments are performed, for the experiment one parameter is set constant and other is kept variable.

·         One by one both the parameters are examined by keeping both the parameters as constant and variable for once.

·         As the higher damper rate is responsible for better suspension system, so to measure the maximum result the damper rate is kept at its peak value and stiffness of spring is maintained to the minimum value.

·          These test are simulated in a simulation or testing software such as Mat lab or Ansys etc.

VARIOUS ELEMENTS IN THE PROCESS OF SIMULATION

1. SEMI ACTIVE SUSPENSION SYSTEM: -

The controlled action of suspension is referred as active or semi active suspension system. In the semi-active suspension system various devices are used for advancement such as air spring, hydraulic suspension devices, self-levelling devices etc. the semi active suspension can be improved by using more control systems. At the time of design or when incorporating new system the factors like weight, size, cost, material etc. should be considered.

In the semi active suspension system a special technology magneto-Rheological dampers (MR dampers) are used. These dampers are used in commercial vehicle as well as in locomotives. It makes the design of actuator precise and simple.

3. CONTROL SYSTEM USED IN SEMI ACTIVE SUSPENSION SYSTEM:-

Control system is the main element of any suspension system to make it an advance system. In a passive suspension system, the automated control system will be added to make it an active suspension system. This is basically the combination of devices whose function is to manage, adjust or control the other system. To build a control system logical control, sequential series, algorithms are used such as on-off systems, logic gates systems, feedback system etc.  

 2. SIMULATION AND TESTING: -

The simulation of the system is performed in attesting software such as Matlab. For which a model of the suspension is developed in a modeling software. During the modeling of system appropriate blocks should be used to simulate he suspension for different types of system.
For the testing of this system a road track is also designed in which lot of irregularities and turbulences are introduced for better testing.
In the testing or study of behavior of semi active suspension system, the two important parameters are studied. Damper rate and stiffness of spring. DAMPER is the element which act as a shock absorbent in suspension system. And damper rate is the measure in the spring of the oscillation to be diminished after a disturbance is created. Stiffness is described as the resistance to deflection in the spring. So these two parameters are to be studied with reference to each other. For the calculation, one of these parameters is kept at a constant value and the behavior of other is measured. Then the second value is kept constant and the behavior of first is examined. A graphical representation and study should be done for better understanding of the results.

CONCLUSION: -

 At the end of the project the feasibility study is done. And the result is defined that whether the system I feasible to adopt or not. The confirmation is done between the simulation result and the result found by experiments. The capacity of dampers will be defined for successful implementation. And material to be used is determined for appropriate stiffness. More researches are going on to make the system more reliable, more comfortable and economical.

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