Technological-based project A Comparison of the MOTION and the MECHANISM among the Mechanical Dog (71101), the Mechanical Giraffe (71105), and the.

Technological-based project

A ComparisonA Comparison

of the of the MOTIONMOTION and the and the MECHANISMMECHANISM among the Mechanical Dog (71101), the among the Mechanical Dog (71101), the

Mechanical Giraffe (71105), and the Mechanical Giraffe (71105), and the Mechanical Turtle (71106)Mechanical Turtle (71106)

Prepared by Prepared by Ng Siu Keung (24)Ng Siu Keung (24)Ng Tsz Fung (25)Ng Tsz Fung (25)Tang Chi Yung (29)Tang Chi Yung (29)Tsang Hing Siu (31)Tsang Hing Siu (31)

Project ObjectivesProject Objectives

1.1. UnderstandUnderstand the mechanism of T the mechanism of Tamiya robots.amiya robots.

2.2. CompareCompare the mechanical perf the mechanical performance of selected Tamiya roormance of selected Tamiya robots. bots.

3.3. Learn to Learn to conductconduct a a technological based project. technological based project.

4.4. UpgradeUpgrade the mechanical the mechanical performance of existing performance of existing robots.robots.

Our learning methods

• Build up the mechanical robots

• Observe their mechanism

• Observe their motions

• Design and conduct experiment to support the findings

• Group discussion

• Literature review

The Mechanical DogThe Mechanical Dog

The Mechanical GiraffeThe Mechanical Giraffe

The Mechanical TurtleThe Mechanical Turtle

Interesting Topics

1. Are the gear ratios correct

2. The relationship between the gear ratio and robot speed

3. The relationship between the gear ratio and the driving force

4. There are still rooms to upgrade the selected robots

Investigate the Gear ratio of the #71105

We observed the gearbox.

A schematic drawing was made and shown below.

4-step reduction

Gear Ratio =42/8×42/12×42/12×42/12

=21/4×7/2×7/2×7/2

=203

The calculation matched the given figure in the manual.

We repeated the calculation, and accepted all gear ratios on the manual are correct.

ExperimentExperiment DesignDesign

Experiment Design

• Speed :

How fast do they run on 1m?Findings :Speed of the giraffe

=1m/50s=0.02m/s.Speed of the dog =1m/40s=0.025m/s. (correct to 2 sig. fig.)

Speed of the turtle=1m/60s=0.016m/s(correct to 2 sig. fig.)

Experiment Design

• Driving force : How long do they push 4 of chesses on 1m?

Findings :Time taken for the giraffe = 65sTime taken for the dog = 70sTime taken for the turtle = 61s

Conclusion:The blocks reduce the speed of the giraffe, dog and turtle .

Experiment Design

How strong do they have?

• Findings: The giraffe stopped

The dog stopped

The turtle went on

Conclusion:

The turtle is the most powerful

Summary of the selected Summary of the selected robotsrobots

Mechanical Dog

Mechanical Giraffe

Mechanical Turtle

Gear Ratio 16.6 58 203

Type Walking Walking Crawling

Speed m/s 0.025 0.02 0.016

Ranking of walking force

3 2 1

Conclusions

• The higher the gear ratio , the slower the movement

• The slower movement , the more driving force from the engine

• The calculation of the gear ratio is simple

Means to improve themechanical performance

After the observation and group discussion, we made the following resolutions:

• Increase the length of the legs

• Change the voltage supply

• Redesign the boots shape

• Apply WD-40 into the gear box

THE ENDTHE END