411 |
Mechanical looseness is a different matter; it suggests |
Mechanical looseness is a different matter; it suggests |
412 |
the following design rules: |
the following design rules: |
413 |
|
|
414 |
- No frictionless pins. For controllers, the frictionless pins are next to useless |
- No frictionless pins. |
415 |
except in special circumstances due to their looseness. |
For controllers, the frictionless pins are next to useless |
416 |
|
|
417 |
|
except in special circumstances due to their looseness. |
418 |
|
|
419 |
- A high gear ratio right after the gear attached to the |
- A high gear ratio right after the gear attached to the |
420 |
control stick is vital |
control stick is vital |
421 |
to alleviate the looseness in gears after that. |
to alleviate the looseness in gears after that. |
422 |
|
|
423 |
- Axles used in gear trains must be supported at several points, |
- Axles used in gear trains must be supported at several points, |
424 |
far enough from each other. |
far enough from each other. |
425 |
|
|
426 |
- All moving |
- All moving |
427 |
joints should be designed |
joints should be designed |
428 |
symmetrically, using e.g. 3-long pins with friction. |
symmetrically, using e.g. 3-long pins with friction. |
429 |
This is similar |
This is similar |
430 |
to taking the numerical derivative of a function |
to taking the numerical derivative of a function |
431 |
|
|
432 |
.. raw:: latex |
.. raw:: latex |
433 |
|
|
434 |
$f(x)$ |
$f(x)$ |
435 |
|
|
436 |
at |
at |
437 |
|
|
438 |
.. raw:: latex |
.. raw:: latex |
439 |
|
|
440 |
$x$ |
$x$ |
441 |
|
|
442 |
as |
as |
443 |
|
|
444 |
.. raw:: latex |
.. raw:: latex |
445 |
|
|
446 |
$(f(x+\epsilon/2) - f(x-\epsilon/2)) / \epsilon$ |
$(f(x+\epsilon/2) - f(x-\epsilon/2)) / \epsilon$ |
447 |
|
|
448 |
instead of |
instead of |
449 |
|
|
450 |
.. raw:: latex |
.. raw:: latex |
451 |
|
|
452 |
$(f(x+\epsilon) - f(x)) / \epsilon$ |
$(f(x+\epsilon) - f(x)) / \epsilon$ |
453 |
|
|
454 |
Even if it is a horrifying thought to LEGO purists, bricks |
- Even if it is a horrifying thought to LEGO purists, bricks |
455 |
can be glued together to obtain an even sturdier structure. |
can be glued together to obtain an even sturdier structure. |
456 |
However, this is seldom necessary. |
However, this is seldom necessary. |
457 |
|
|
458 |
Handles |
Handles |
459 |
------- |
------- |