Conceptual design

Pentagraph leg

• Servo motors are used for movement
• Arduino is used for input command
• The bot shows walking mechanism
• Obstacles are sensed by IR sensors.

Mammalian leg

• DC motors are used for movement
• Bluetooth module is used for instructing.
• voice command is given.
• The bot shows crawling motion

Pantograph Leg

• Touch sensor is used to detect obstacles
• wheels are used for movement.
• touch sensor is used.
• The bot shows rolling motion

Simple two-link leg

• Stepper motor is used for movement of bot
• input is given through arduino
• The bot shows walking mechanism
• Ultrasonic sensor is used .

Identified and prioritised objectives

1. safety
2. battery efficiency
3. user friendly
4. cost efficient
5. compact

Weightage of objectives

Objectives	Weightage
safety	9
user friendly	8
cost efficient	7
battery efficiency	6
compact	5

PUGH chart

objectives	Simple two-link leg	Mammalian leg	Pantograph Leg	Pentagraph leg
safety	++	+	-	DATUM
cost efficiency	-	+	++	DATUM
user friendly	+	-	+	DATUM
compact	++	--	+	DATUM
battery efficiency	++	-	+	DATUM
+ score	34	19	31	-
- score	7	14	8	-
total	28	5	23	0

the best concept selected is Simple two-link leg.

Justifications

Simple two-link leg

Objectives	Score given	Justification
Safety	8	The bot is most safe to use
Cost efficient	6	It is expensive because the input is given using arduino
User friendly	7	A person should know how to program using arduino
compact	7	It is compact and does not consume a lot of space
Battery efficiency	9	Its charging and battery lasting capacity is long (4-5) and does not have any issues with battery

Mammalian leg

Objectives	Score given	Justification
Safety	7	The bot is safe to use
Cost efficient	5	it is a little expensive
User friendly	6	the students should be guided and accompanied by a supervisor
compact	5	the bot is a little big
Battery efficient	5	The bot's charge does not last for to long

Pantograph Leg

Objectives	Score given	Justification
safety	6	It is not very safe because touch sensors are very delicate
Cost efficient	7	it is cheaper compared to pentagraph leg mechanism and mammalian leg mechanism
User friendly	8	The bot is easy to use for students
compact	6	The bot is of average size and does not require special extra space
battery efficiency	6	The battery lasts up to 2-3 hours after continuous use

Pentagraph leg

Objectives	Score given	Justification
Safety	9	DATUM
Cost effective	8	DATUM
User friendly	9	DATUM
compact	7	DATUM
battery efficiency	7	DATUM

identified list of sub-functions

• power supply
• storage and processing of data
• accepting instructions
• oscillation of limbs and movement of bot
• sensing the obstacles

Function tree vs Component hierarchy

Subsystem tree

System interaction table

	interaction	giving instructions	Movement and oscillation	sensing
power supply	data	-	-	-
	energy	yes	yes	yes
	spatial	-	-	-

	interaction	power supply	Movement and oscillation	sensing
giving instructions (input)	data	-	yes	yes
	energy	-	-	-
	spatial	yes	yes	-

	interaction	power supply	giving instructions	sensing
Movement and oscillation	data	-	yes	yes
	energy	yes	yes	yes
	spatial	-	yes	yes

	interaction	power supply	giving instructions	Movement and oscillation
sensing	data	-	-	yes
	energy	yes	-	-
	spatial	-	yes	yes