BASIC SIMULINK

AIM:

1. To evaluate the equation by using simulink blocks.

2. Suspension system comparison using simulink.

KEYWORDS: Shock absorber, Damping co-efficient, stiffness, sprung mass and unsprung mass.

SOFTWARE: Matlab, Simulink

OBJECTIVE:

• To calculate the equation by using simulink.
• Run the suspension systems and compare the systems according to the graph obtained.

INTRODUCTION: Inorder to solve the equation, we can use sum, subtract and product (individual operator) or function operator. By using function operator block, it is easy to model and take less time to create a model.

STUDY 1:-

In the above model is discrete system which is varying with respect to time. The ramp block is given as input , function block is given for the expression which solves quickly, the result of the above model is shown by display block and the variation wrt time is shown by scope block.

In the above model, the input is taken constant block ia given as 2. i.e., (x = 2) by theoritically the value of y(x) at x = 2 is equal to 49, the result shown in siimulink as same. By using display block for output of the equation.

STUDY 2:-

In the above simulink suspensions system, there are 3 different suspensions are used to compare and study the suspension systems.

1. Nonlinear Spring: A nonlinear spring has a nonlinear relationship between force and displacement. A graph showing force vs. displacement for a nonlinear spring will be more complicated than a straight line, with a changing slope.

2. Variable Spring: A linear spring is one with a linear relationship between force and displacement, meaning the force and displacement are directly proportional to each other. A graph showing force vs. displacement for a linear spring will always be a straight line, with a constant slope.

3. Shock absorber: The spring mass damper system consists of discrete mass nodes distributed throughout an object and interconnected via a network of spring and damper.

4. Damper: It resists the motion via viscous friction. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation.

5. Stiffness: The stiffness, k, of a body is a measure of the resistance offered by an elastic body to deformation.

6. Sprung & unsprung mass: In an automobile, the sprung mass act as very important role which refers the part which is dependent on the spring is called as sprung mass. The parts which is independent to suspension is known as unspring mass.

7. The natural frequency is the rate at which an object vibrates when it is not disturbed by an outside force.

The above model which includes the spring block, stiffness block, damper block, mass block, velocity source block, solver configuration block, sensor block, spectrum analyzer and scope block.

The above model is input velocity for all the suspension system, in which sine wave and pulse generator are used to create the input velocity. The simulink - PS convertor block is used to convert the block value to physical system value to the model. This value is used to velocity source which is common for all the suspension systems. The block represents an ideal source of velocity that generates a velocity differential at its terminals proportional to the input physical signal. The source is ideal in a sense that it is assumed to be powerful enough to maintain specified velocity regardless of the force exerted on the system. The velocity refers to suspension movement which indirectly the vehicle moving in uneven road surface which creates vibration. Inorder to avoid the vibration, the 3 different systems are used to study the variation of wheel with respect to the time and displacement. The velocity source uses common reference which defines that is fixed wrt the velocity. The input velocity passes to all the suspension system which defines the variation of the suspension system wrt time and displacement. In variable spring system, the spring used as linear spring only difference is pitch rate and damping system which is connected parallely. When vibrates, the spring compressed and the damper resist the motion of spring. In nonlinear spring, the spring coil diameter is varing and gives more vibration by using nonlinear damping system. In spring mass damper system, the system connected in series way which reduces the oscillations more when compare to the other two suspension system.

OUTPUT:

STUDY 1:-

STUDY 2:-

CONCLUSION:

• The equation calculated by using simulink and obtained the result.
• By comparing all 3 suspension system, the variable system is sudden incresing and sudden decreasing wrt the displacemnt and time. But in nonlinear and spring mass damper system, the variation is fluctuates accordingly to the damping system.