This report will describe a possible project to be developed using the LEGO Dacta kits. In developing this project idea, the goal has been to include concepts and ideas from several different branches of engineering so as to better inform incoming fresh man engineers of the characteristics of their chosen fields.
The description below includes not only a general overview of the project, but also an explanation of some of the engineering
concepts that are examined. Also, a description of how the project could be presented in an educational atmosphere is provided.
Project Description
The proposed project is a mobile, self-adjusting artillery cannon. Students would be required to design and build the machine, including the trigger mechanism and a range-finding device. Extensive software control would have to be developed, reacting t o sensory inputs and adjusting the action of the vehicle accordingly.
There are many engineering concepts involved in this project. The most obvious is simple Newtonian physics. The equations governing projectile flight are well understood, and freshmen engineers will have been introduced to them in their entry-level phy sics courses. Students would be required to measure the muzzle velocity of the projectile, and the firing angle. A range-finder is somewhat more difficult to develop, and may require additional equipment not included in the kit (see below).
The mobile nature of the vehicle would require some knowledge of gearing systems and other mechanical engineering concepts. In addition, the software control requires real-time programming, which should allow potential computer science majors to explo re their area of interest.
Because the artillery unit must be self adjusting, it must be able to examine sensory inputs and adjust to an ever-changing environment. This is a crucial engineering problem applicable to all fields. In most systems, some sort of feedback is used to r egulate the operation of the device. The artillery unit is no different. If a potential target moves, the vehicle must be able to track it and adjust the firing parameters in order to be successful in targeting the opponent.
One of the more important educational aspects of this project is the integration of all of these diverse concepts into a functional system. Taken by themselves, each of the requirements is relatively easy to satisfy. Making the separate devices work to gether is a completely different problem. Another important educational goal is to develop the students' problem-solving abilities. They must be able to break the problem down into sub-problems and integrate the solutions of the sub-problems. This is a nother technique common to all fields of engineering.
The team concept is central to this project. Each sub-problem can be assigned to a different team member. One person may be
responsible for the ranging device, while another controls the firing angle. Each would be required to write the code for his o
r her module, with a third person writing the "wrapper" code that runs the system.
Competition
Competition is fun. It also inspires the contestants to think creatively to get the edge over everyone else. Competition could
easily be integrated into this project. Vehicles could be pitted against each other, with the first to score a hit being dec
lared the winner. This also brings up the possibility of students incorporating clever diversionary tactics into their designs. While this may or may not involve new engineering aspects, it does require creativity, which is essential to all engineering
designs.
Extra Equipment and Project Modifications
As mentioned above, this project may require additional parts not included in the LEGO Dacta kits. Specifically, a sonar or other ranging device may be needed if it is not possible to judge distances with the given equipment. More LEGO sensors, especia lly light and angle sensors would be extremely helpful. However, one must be careful not to provide too many resources. After all, the real world does not contain infinite raw materials.
As stated before, an accurate directional sensor is needed to track the target. The LEGO Lamp/Light Sensor pair is fairly accurate, but only at short distances (less than one foot). The MIT Infrared transmitter/receiver would be ideal if it could be ad apted to use the LEGO control box.
The project could easily be modified to enhance the requirements. For example, drag forces on the projectile could be taken into
account. If a mobile unit proves to be too difficult to design (hitting a moving target is a VERY difficult problem), fixed
-position units could be substituted. The competition could be modified. Cannons could fire at a fixed position, and the design that hits closest to the target is declared the winner.
Conclusion
The mobile artillery cannon includes engineering concepts from many fields, and should give freshmen engineers an opportunity to explore the various disciplines. Students will also learn how to work together, and what makes an effective team. Competiti on will drive creativity. Most of all, the students should have a lot of fun.