Introduction: 【Joint Institute2019 | Group5: Infinity】Deployable Bridge

Who are we?

- We are 2019 freshmen, and our team name is ‘Infinity’ which means that our imagination and creativity as engineers are infinite and limitless.

About Joint Institute

- The UM-SJTU Joint institute (JI) was cooperatively established by Shanghai JiaoTong University and the University of Michigan in 2006 in Minhang, Shanghai, China. The goal of this Joint Institution is to build a world-class teaching and research institute in China, nurturing innovative leaders with global visions.

Step 1: About the Competition

Competition is a situation where people challenge each other in order to reach a higher goal than other people. During the competition, people strive to make their work best and overtake the others. Hence, it is also an opportunity of enhancement and promotion of oneself.

All the freshman in VG 100 is divided into twenty groups to make bridges until October 16. After every team has finished making their own bridges, there would be a competition on Wednesday, October 16 (also called ‘game day). During the ‘competition’, each team will show their bridges’ operation and compete against each other based on their operations according to some given rules.

Step 2: Rules for the Competition


Length: 700mm – 750mm

Size: 160mm – 200mm

Load: 1000g or 3.33 times of bridge

Deployment: Should be automatically within 1minute

Retraction: Should be retracted within 1 minute

Bonus: Aesthetic, Uniqueness and originality, Greatest ration of load/bridge weight, and other aspects


I. Every team must be using balsa wood and wood glue to construct their bridges. Cables are allowed to use, but must be loosen during the Load test part. Other metals can only be used with TA or instructor’s written permission.

II. The length of the bridge should be at least 700mm. If the bridge is longer than 700mm, then the distance between two abutments can be adjusted.

Grading Rules

There are five main parts of grading rules: Size, Deployment, Retraction, Load, and Bonus.

Step 3: Materials

Step 4: Concept Diagram

The bridge is consisted of two parts, there are two micro servo motors in the middle, so that it makes the bridge can be retracted and deployed. Also, there is another gear motor at the end of the bridge which makes the bridge able to deploy all the way up to the end (so that it can be fitted in the box).

Step 5: Component Fabrication

Step 6: Insert ‘basis 2’ to ‘basis 1’

Step 7: Repeat Step 6 for Another 4 Times

Step 8: Insert Two Wood Battens Into the Holes on the ‘basis 2’

Step 9: Repeat Steps 6~8 to Make Another Half of the Bridge.

Step 10: Stick the Board to the Main Body of Bridge

Step 11: Use Micro Servo to Connect Two Main Bodies of the Bridge.

Step 12: Connect the Gear Motor Part With the Main Part of the Bridge

Step 13: Final Front View

Step 14: Final Left-side View

Step 15: Final Top View

Step 16: Result

Though we tried our best, our team only ranked 19th out of twenty teams. However, after the game day we made second model of bridge to prove that we can make deployable bridge, if we got just little bit of time. The link (URL) below is the place where the readers can watch our bridge’s working on Youku.


Step 17: Manual