Tuesday, June 18, 2013

TECHNIC Liftarms: Angles Built In

How are you LEGO Mindstorms NXT hobbyist? I hope, You still remember about Tilting the LEGO World: Diagonal Bracing. This posting continue it. As noted earlier, over the past several years LEGO has introduced a number of new TECHNIC parts that divert from the concept of straight beams and 90-degree connectivity. We could review numerous parts here, but there simply is not enough room in the my posting for this. Some of the more popular ones fit in the common group of studless beams, called l/ftarms. They come in many shapes and sizes, you can use them to connect parts at differing angles, and you often see them in robot grabbers, fingers, ball casters, and so on. Figure 1.9
shows a sample ofliftarms from the TECHNIC line.

Figure 1.9 A Variety of Liftarms

Liftarms are quite versatile parts that often come to the rescue when you're trying to connect components in odd ways. You will see several samples that use liftarms in differing ways. Some use them to connect motors at odd angles, and others use them for bracing. Figure 1.10 shows some examples of how you can use liftarms to brace a structure. Using your own parts, try to re-create this sample.You will notice that you can connect the liftarms at only certain holes and angles; not every combination works. However, by using different types of liftarms, you can see how each one connects a little differently, thus providing a number of ways to brace your robot.

It is also important to think outside the box here. With many of the newer TECHNIC parts, your models do not have to follow the traditional square or rectangular building approach. For example, using Figure 1.10, you could extend one of the liftarms upward to mount a sensor, or use it to connect a servo motor to provide a drive mechanism mounted at an angle. Try to experiment with connecting liftarms and beams together and see how you can brace your structure or extend components of your robot at odd angles. The important thing to remember here is that you don't always have to follow the traditional approach of connecting beams and bricks at 90-degree angles.

Figure 1.10 Liftarm Bracing

Lego mindstorms NXT hobbyist, now we finished our discuss about understanding LEGO geometry. Lets, we review it. Did you survive the geometry? You can see it doesn't have to be that hard once you get familiar with the basics. First, it helps to know how to identify the beams by their proportions, counting the length and width by studs, and recognizing that the vertical unit to horizontal unit ratio is 6 to 5. Thus, according to the simple ratio, when you're trying to find a locking scheme to insert axles or pins into perpendicular beam holes, you know that every five bricks in height, the holes of a crossed beam match up. Also, because three plates match the height of a brick, the most compact locking scheme is to use increments of two plates and a brick, because it gives you that magic multiple of 5. If you stay with this scheme, the standard grid, everything will come easy: one brick, two plates, one brick, two plates... To fit a diagonal beam, use the Pythagorean theorem. Combinations based on the triad of 3-4-5 constitute a class of easy-to-remember distances for the beam to make a right triangle, but there are many others.You also were exposed to the TECHNIC liftarm, which offers countless connectivity options for your robots. Remember to think outside the box and not assume that you have to build via the traditional square or rectangular approach. Explore with the parts you have in your kit, and discover new ways to connect parts using studless building techniques.You will soon find that this way of building offers great flexibility in design.

Ok.. lego mindstorms NXT hobbyist, I hope you have understanding LEGO geometry, Now. 
Next, I will post about playing with gear.Do you know gear? follow next posting... see you!

No comments:

Post a Comment