Monday, November 10, 2008

Building Strategies

(NOTE: This entry is a work in progress)

Chapter six of the Lego Robotics book emphasizes the importance of the structure of your Lego Robot. When creating a robot, the main goals you want to keep in mind, are that you want to keep the robot as lightweight as possible - using minimal amounts of bricks - without sacrificing the structural integrity of your robot and making it very vulnerable to forces such as compression and tension (unless you have alternative intentions for your robot). Compression is a force exerted on structures that pushes and tries to make the structure smaller, while Tension is the opposite; it stretches and tries to elongate the structure. To counter both forces and to make your robot more 'economical' by using less parts for more strength, a variety of different supports must be used in combination (ex: beams and 'L-beams' must be used together).

When it comes to structural integrity, protecting the gears and motors of your robot are vital, as in relation to the human body, they are the heart of your robot; driving it forwards and turning it into the unstoppable monster, or lithe dragster that it is. The important thing to remember with gear and wheel placement is that the closer the gear/wheel is to its supporting beam the better. Having the gear/wheel closer to its supporting beam means that less force (generated by the mass of the robot for example) will be pushing down on the axles and pushing your gears apart. Another point to remember when supporting gears is to mount supports in line with the gears, as illustrated in 6.10, 6.11 of the robotics book. This means that if your gears are operating horizontally - match parallel support beams horizontally. Having the axles snap under multiplied pressure, or your gears failing to function as they slide apart are realities that can be easily solved by remembering these points.

Also, when constructing a robot it is also important to remember to balance the robots weight between both the driving wheels and any other wheels on the robot (generally slightly more weight on driving wheels) so the robot isn't off balance.

Finally, another important thing to remember is to build your robot with modularity. This means that you should construct portions of the robot together so that you can easily attach and detach certain portions of the robot to easily remake the structure. When building a robot using both the Technic and Mindstorms kits, also known as a hybrid, modularity is one advantage the robot has compared a purley Mindstorms kit in most cases (Hybrid robots also tend to be heavier and more stable) .

1 comment:

hksong said...

Clear and obvious explanation. It was really helpful for my summary and building a totally new one last time ^^