PUGH CHART

Design Objectives and Concept Evaluation

Design Objectives	Weights	Design 1	Design 2	Design 3	Design 4
Safety	9	+	+	Datum	+
Ease of use	7	++	++	Datum	+
Portability	5	-	-	Datum	-
Use of standard parts	6	+	+	Datum	+
Cost	6	+	++	Datum	-
Score (+)		31	41	0	22
Score (-)		5	5	0	11
Total		26	36	0	11

5.1 Justification for score given

Design No.	Objective	Score Allocated	Justification for the Score
1	Safety	9	Motor-wheel arrangement has fewer complicated moving parts, reducing the chance of failure.
1	Ease of use	14	Simple to operate because wheels are directly driven by standard motors.
1	Portability	-5	Wheels and motors arrangement adds some weight and makes the design heavy to carry.
1	Use of standard parts	6	Uses commonly available DC motors, wheels, shafts and basic electrical components.
1	Cost	6	Requires inexpensive and easily available motors, wheels and construction materials.
2	Safety	9	It operates at low speed and can be covered with cardboard to prevent contact with moving parts.
2	Ease of use	14	Provides simple and reliable arm movement for presenting the gift.
2	Portability	-5	Additional arm mechanism and supporting structure slightly increase size and weight.
2	Use of standard parts	6	Uses standard DC motors, shafts, pins and linkages.
2	Cost	12	Mechanism is mainly made from cardboard and inexpensive standard components.
3	Safety	0	Selected as a reference for comparing other designs.
3	Ease of use	0	Selected as a reference for comparing other designs.
3	Portability	0	Selected as a reference for comparing other designs.
3	Use of standard parts	0	Selected as a reference for comparing other designs.
3	Cost	0	Selected as a reference for comparing other designs.
4	Safety	9	It can be enclosed and operated at low speed, providing safe operation.
4	Ease of use	7	Its arrangement provides controlled movement even if the system is more complex.
4	Portability	-5	The conveyor, motor and additional components make the robot slightly larger and heavier.
4	Use of standard parts	6	Uses commonly available servo motors, DC motors, sensors and electronic components.
4	Cost	-6	Requires additional motors, sensors and conveyor components, increasing overall cost.

5.2 Selected Design

5.3 Product Architecture

Product Architecture – Welcome Robot

The product architecture of the Welcome Robot describes its main components and how they work together to welcome visitors.

Input Unit: Detects visitors using sensors or receives input through buttons.

Processing Unit: A microcontroller such as Arduino processes the input.

Output Unit: A speaker gives welcome messages, while LEDs and a display provide visual information.

Power Supply: Provides electrical power to the robot.

Mechanical Structure: Includes the robot's body, head, base, and supporting frame.

Software Unit: Controls the sensor, greeting message, and output functions.

User Interaction Unit: Allows visitors to interact with the robot and receive information.

Product Architecture Diagram

Working principle: Input → Processing → Output. The sensor detects a visitor, the controller processes the signal, and the speaker plays a welcome message.

5.4 Function Clustering

5.5 Interaction between subsystems

Activity 3: Interaction Details

Subsystem 1

Parameter	Subsystem 2	Subsystem 3
Spatial	Guest position	Gift holding position
Data	Guest detection signal	Sending alert to offer gift
Material	Electrical sensor signal	Electrical signal sensor

Interaction Details

• Detect guest and get alert signal to welcome and interaction system.
• Detect guest position and alert themselves to offer gifts.
• Send information detected by sensor to control unit.

---

Subsystem 2

Parameter	Subsystem 1	Subsystem 3
Spatial	Guest position	Hold hamper and move it securely
Data	Detection signal	Hamper offering command
Material	Electrical signal	Electrical control signal

Interaction Details

• Coordinates the position of guest and hamper.
• Initiates the gift-hamper offering sequence.
• Activates the gift hamper offering mechanism and controls it.

---

Subsystem 3

Parameter	Subsystem 1	Subsystem 2
Spatial	Guest position	Hamper position
Data	Position information	Offering status
Material	Electrical control signal	Electrical control signal

Interaction Details

• Gets information about guest position.
• Ready to offer gift hamper.
• After handing gifts to guest, it will return to its initial state.