Control Systems - Block Diagram Reduction Basics & primary seven rules for block diagram reduction

1. Block Diagram Reduction
- Ameya P. Nijasure
napradeep@mes.ac.in

2. Block Diagrams
● Representation of system function by blocks connected by lines.
● Represents relationship between systems & subsystems.
● Applications include engineering in hardware design, electronic design, software design,
and process flow diagrams.
Consider an example
● There is an input & output.
● Direction of function can
be either forward(i/p to
o/p) or feedback(o/p to
i/p).
● G & H are representation
of Transfer functions(t.f.)
of each sub system.
● Lines represents
relationships between
subsystems.

3. Block diagram components

4. Block diagram Reduction
R(s) Y(s)Converting these complex systems into
Simple systems
● One t.f representing components of
all subsystems.
● Using standard rules
Points to remember
● The product of the transfer function in the feed forward direction must remain same.
● The product of transfer functions around the loop must remain same.

5. BLOCK DIAGRAM REDUCTION RULES
NOTE : BLOCKS IN PARALLEL MUST HAVE
SAME DIRECTION.

6. BLOCK DIAGRAM REDUCTION RULES

7. BLOCK DIAGRAM REDUCTION RULES

8. BLOCK DIAGRAM REDUCTION RULES
NOTE :
● TO ELIMINATE FEEDBACK LOOP WE NEED ONE FORWARD PATH TF , ONE FEEDBACK TF, ONE
SUMMING POINT & ONE TAKEOFF POINT.
● G1 & H1 CAN BE UNITY FUNCTIONS..

9. Thank you….!!
- Ameya P. Nijasure
napradeep@mes.ac.in