 Hello everyone welcome to this session I am Priyanka Bansode and today we are going to study about introduction of control system. These are the learning outcomes of this video lecture. At the end of this session students will be acquainted with basics of control system and identify various control systems. These are the contents we will be covering in this session. Before moving towards control system let us start with some definitions. So first one input, input is the stimulus or excitation applied to a system from an external source in order to produce the output then output. So output is the actual response obtained from the system. So you can see in figure 2 when input is applied to the system output will generate accordingly. After input and output we will see the system. System is a combination or arrangement of different physical components which act together as an anti-unit to achieve certain objective. Let us take an example of classroom a room that is along with the combination of benches, blackboards, fan, lighting all these arrangements etc. So it can be called as classroom and second one a lamp made up of glass filament. So it is also physical system. Now we are moving towards control. So control means to regulate, to direct or we can say to command a system so that the desired objective is attained or the desired objective is achieved. Now we have to combine these two words that is control plus system. It becomes control system. So it is an arrangement of different physical elements connected in such a manner so as to regulate, direct or command itself or some other system. Let us consider the example of control system. First one if in a classroom professor is delivering the lecture the combination becomes a control system as he or she tries to regulate the command the students in order to achieve the objective which is to impart the good knowledge to the students. And the second example is a lamp. So lamp is switch is nothing but it is a control system. Now before moving towards pause this video for few seconds and you have to think and write down requirements of good control system. These are the requirements of good control system. So first one for good control system accuracy should be very high then it should be very sensitive to the input signals. Then third noise it should be insensitive to the input signals then the fourth one it is stable for all the variations occurred in the system. Then bandwidth should be very large and a good control system should have the high speed that is the output of the system as fast as possible. And the last one for good control system oscillation of output should be constant. Now we will move towards classification of control system. Control system is broadly classified as follows. So here these are the types of control systems. Let us see each control system in detail. First one natural control system. The biological systems inside the human beings are of natural type. One body is the good example of the natural system. Then second manmade control system. The various control systems we are using in our day to day life and which are designed and manufactured by the human beings only. So manmade control systems again is divided into two parts that is manual and automatic control system. For example vehicles, switches, accelerator, braking system etc. So these are the examples of the manmade control system. Then third combinational control system from the name it is the combination of natural and the manmade. So example driver driving the vehicle means for successful operation of system it is very necessary that natural systems of driver along with the system in vehicle must be active. Next type will be time variant system. Here all the parameters in the system vary with respect to time are called time variant system. Example is space vehicle whose mass decreases with time as it leaves earth. So the mass is parameter of the space vehicle system. Next time invariant system all the parameters in the system are constant and the parameters does not vary with respect to time is known as time invariant system. So here different electrical networks consisting of resistance, inductance, capacitance. So all these parameters are time invariant system. As the values of these elements are constant and these are not the function of time. Then linear and long linear system. So linear means a system in which the principle of superposition is valid. Here it has to follow the two properties, additivity and the homogeneity. So first additive property means what for example f of x plus y is equal to we can write f of x plus f of y. So here x and y belongs to the domain of the function f. Then second example f of alpha x is equal to alpha into f of x. Here alpha is the scalar constant. Now non-linear systems. So here a system in which the principle of superposition is not valid. For example f of x is equal to x square. So x is replaced by x1 plus x2. So we can write the equation f of x1 plus x2 is equal to x1 plus x2 bracket square. But this is not equal to x1 square plus x2 square. So this is non-linear system. Next will be continuous time and discrete time system. So continuous time means all the system variables are function of a continuous time variable t. Example analog system. Then discrete time means one or more system variables are known as discrete interval of time. For example digital system. So this is continuous time signal and this is discrete time signal. Now the next one deterministic and stochastic control system. So deterministic means system in which the output can be predicted due to the changes in the input entering into the system. Means here the response of the system to the input as well as the behavior to the external disturbances is predictable and it's repeatable then the system is said to be deterministic. And stochastic means a system in which output cannot be predicted due to changes in the input. So the system is said to be stochastic in nature. Now we will see the lump parameter and the distributor parameter. So lump parameters means are the systems in which whose equation of operation is ordinary differential equation. For example in electrical networks we use the differential equation with different parameters like resistance and inductance and distributor parameter means these are the systems in which whose equation of operation is partial differential equation. So for example in transmission line we use differential equation with its parameters like resistance inductance these are totally distributed along it. So in short you have to remember lump parameters are based on ordinary differential equation and the distributor parameters are based on partial differential equation. Now single input single output control system. So system having only one input and only one output and MIMO means multiple input multiple output control system. A system having multiple inputs and multiple outputs it's called multiple input multiple output control system. Now this is important classification of control system, open loop and closed loop control system. So open loop and closed loop system you can see in the figure open loop means a system in which input signal is independent on the output signal is known as open loop control system and the closed loop means a system in which input signal is dependent on the output signal is known as closed loop control system. So these are the types of control systems. These are the references of this video lecture. Thank you.