5.1 Pugh chart

Design Objectives	Weights	Design 1	Design 2	Design 3	Design 4
Safety	9	Datum	+	0	+
Ease of use	7	Datum	+	+	0
Portability	5	Datum	+	+	+
Use of standard	6	Datum	0	+	0
Cost	6	Datum	+	+	+
Score(+)		0	27	24	20
Score(-)		0	0	0	0
Total		0	27	24	20

5.2 Selected Design

Design No.	Objective	Score Allocated	Justification for the Score
Design 1	Safety	Datum	Reference design used for comparison
Design 1	Ease of use	Datum	Reference design used for comparison
Design 1	Portability	Datum	Reference design used for comparison
Design 1	Use of standard parts	Datum	Reference design used for comparison
Design 1	Cost	Datum	Reference design used for comparison

Design 2	Safety	8	Improved safety compared with the datum design
Design 2	Ease of use	8	Simple controls and easy operation
Design 2	Portability	8	Compact and easy to carry
Design 2	Use of standard parts	7	Uses standard components where practical; similar to datum
Design 2	Cost	8	Expected to be more cost-effective than the datum

Design 3	Safety	7	Safety is comparable to the datum design
Design 3	Ease of use	8	Simple mechanism makes it easy to operate
Design 3	Portability	8	Compact structure supports portability
Design 3	Use of standard parts	8	Uses commonly available standard parts
Design 3	Cost	8	Standard parts help keep cost manageable

Design 4	Safety	8	Improved safety compared with the datum design
Design 4	Ease of use	7	Ease of use is comparable to the datum design
Design 4	Portability	8	Compact design is easy to move
Design 4	Use of standard parts	7	Standard-part use is comparable to the datum design
Design 4	Cost	8	Expected to be more cost-effective than the datum

Subsystem 1	Subsystem 2	Subsystem 3	Interaction Details
Spatial	yes	yes	The body unit and the sensing unit are connected to the leg unit to work as a system.
Data	yes	no	The leg unit and sensing unit interact or work through signals, but it is not connected to the body.
Material	no	yes	The leg unit is connected to the body unit by joints to make a mechanism.

Subsystem 2	Subsystem 1	Subsystem 3	Interaction Details
Spatial	no	yes	The sensing unit is physically mounted on the body unit.
Data	yes	yes	The body unit or leg unit move because of the sensing unit, which gives or transfers signal.
Material	yes	no	The body provides mechanical support to the sensing unit.

Subsystem 3	Subsystem 1	Subsystem 2	Interaction Details
Spatial	yes	yes	The sensor is mounted on the body and the leg unit is physically connected to the body.
Data	no	yes	The sensor communicates through signals with body whereas leg unit doesn't communicate with body through signals.
Material	yes	yes	Both are connected through joint linkages to the body unit.