the revolting bridge designed by leonardo da vinci
DESCRIPTION
In his design of the revolting bridge, Leonardo relies on an antique pretext but solves the problem of defending the structure against the peril of enemies in a fancy way: with hostile troops advancing, the bridge could swing around a pylon, separating it from the shore. The enemy could then no longer cross the river. Simple, but completely efficient. Interesting projects designed and programmed by my Junior High studentsTRANSCRIPT
By: Yusuf Juan & Jeffer
Leonardo da Vinci (1452-1519), Florentine artist, one of the great masters of the High Renaissance, celebrated as a painter, sculptor, architect, engineer, and scientist. His profound love of knowledge and research was the keynote of both his artistic and scientific endeavors. His innovations in the field of painting influenced the course of Italian art for more than a century after his death, and his scientific studies—particularly in the fields of anatomy, optics, and hydraulics—anticipated many of the developments of modern science. Microsoft ® Encarta ® 2007. © 1993-‐2006 Microsoft Corporation. All rights reserved.
� Bridges have always been important to human societies as a means to cross obstacles such as rivers, lakes, or abysses. Stable and reliable bridges have made the transportation of people and goods possible, establishing long-‐range economical connection on a large scale. In particular, in medieval ages, with roads and rivers providing the major means of inland transportation, bridges were crucial.
� Bridges were also important for military reasons. They could form a bottleneck that hampered enemy troops laden with heavy artillery. Bridges were of paramount importance in military strategies because they formed a point of defense against advancing enemies, as well as represented primary targets for hose very adversaries.
� Leonardo drew the revolting bridge in Milan in the 1580s, and the drawing is today contained in the Codex Atlanticus. In his letter t Duke Ludovico, he talks of “plans for very light yet stable bridge.”
� Figure 1-‐1, Leonardo’s drawing of the Revolting bridge
� In his design of the revolting bridge, Leonardo relies on an antique pretext but solves the problem of defending the structure against the peril of enemies in a fancy way: with hostile troops advancing, the bridge could swing around a pylon, separating it from the shore. The enemy could then no longer cross the river. Simple, but completely efficient.
� Generally speaking, building a bridge with LEGO is not the most complex thing in the world, with Leonardo’s revolting bridge, however, the fulcrum it swings around poses a particular challenge. The fulcrum is the only point from which the whole structure is suspended. This means everything must be in balance and stable while allowing for movement.
� For the implementation of the fulcrum with LEGO, we use a turntable that is fixed at base plate. This provides both the required stability and flexibility needed (Figure 1-‐2).
� Figure 1-‐3 shows the complete revolting bridge robot. Note that we have added an ultrasonic sensor to Leonardo’s original design on the far-‐side base of the bride. It is used to automatically swing the bridge when the sensor spots approaching enemies – a contraption Leonardo certainly would have liked.
Not surprisingly, the general flow of the program for the bridge is not very complex (Figure 2-‐1):
� Wait for enemies to approach the structure � Once the ultrasonic sensor has detected enemy tanks, moves the bridge to the side by running the two motors,
� Wait until the sensor does not detect anything anymore.
� Reset the bridge to its original state
� LEGO MINDSTORMS NXT Software � Again, we start with a loop block that turns forever (Figure 2-‐2)
� Now we wait the ultrasonic sensor detects an approaching object. Therefore, we insert a loop block again, this time appropriately configure by the ultrasonic sensor (Figure 2-‐3).
� Once an object is detected, switch the bridge away by running the two motors that operate the winches. For synchronizing these two motors, use a Move block that is configured to run them in opposite directions (Figure 2-‐4).
� Now that the bridge is switching away, wait for the ultrasonic sensor to detect that there is no object, which means that the possible enemies have retreated. As before, use a loop block configured by the ultrasonic sensor; this time, the stop criterion is vice versa (Figure 2-‐5).
� Once no object can be detected any longer, the bridge is switched back by an appropriated configured Move Block (Figure 2-‐6).
� And we’re done. Figure 2-‐7 shows the complete NXT-‐G program.
� In this Leonardo da Vinci’s revolting bridge project, we were acquainted with another type of NXT sensor: the ultrasonic sensor. We know what to use if for, how to use it, and how to access it programmatically in NXT-‐G programming language.
� Furthermore and most importantly, we know about how to use a turntable which provides both the required stability and flexibility needed for the fulcrum which is the only point from which the whole structure is suspended. We also learn about how to synchronizing motors and have seen how to use strings to transfer motor control to remote hardware components.
� We would like to thank Mr. Haoken, our Science Teacher and robotics trainer, for his guidance in hardware and software challenges. A special “Thank You” to our principal Ms. Ilbeth for her kind assistance. Lastly, we would like to thank our family for supporting our project!