Q4. (4 marks) A control system has the following transfer functions in its block diagram: y(s)=(20s+1)15e12su(s)+(6.0s+1)5e2sd(s)AssumeGt=Gm=Gv=1.0 Where, in deviation variables, y is the process output variable, u controller output and d is the disturbance. Design a feedforward controller based on dynamic models to achieve 'perfect' control for this process. Is this feedforward controller physically realizable? If the answer is no, what approximation can be used to obtain a physically realizable feedforward control law. Justify your