For the liquid storage system shown in Fig. E15.4, the control objective is to regulate liquid level h₂ despite disturbances in flow rates, q₁ and q₄. Flow rate q₂ can be manipulated. The two hand valves have the following flow head relations: 

Do the following, assuming that the flow transmitters and the control valve have negligible dynamics. Also assume that the objective is tight level control.
(a) Draw a block diagram for a feedforward control system for the case where q₄ can be measured and variations in q₁ are neglected.

(b) Design a feedforward control law for case (a) based on a steady-state design (Eq. 15-40)

(c) Repeat part (b), but consider dynamic behavior.
(d) Repeat parts (a) through (c) for the situation where q₁ can be measured and variations in q₄ are neglected.