请教如何确定执行机构的初始位置？呵呵

planar8514

前几天搭建了魔方机器人mindcuber，然后借用那个结构自己试着写程序。发现一个问题，就是电机的初始位置如何设置。测试网上的执行程序时，感觉作者也没有太多的处理这个问题。比如转台运行若干次后，会出现角度偏差，这时再把魔方放到上面的话，运行就会出问题，出现机械臂不能成功翻转魔方的情况。

我想请教一下，搭建机器人的时候，类似这种机械臂或转台的初始位置，只能靠搭建保证，而很难实现系统的自动修正？

ccxl

查找mindcuber的文档，你就会发现有相关的说明，在程序运行让你放入魔方时，如果不放入魔方，而是按NXT上左右按钮，就可以调节转台的初始位置，机械臂好象不用调的，不过，初始位置有放对。

ccxl

How to: Robot operations  

MindCuber can solve a standard 3x3x3 Rubik’s Cube. It works best with cubes with the standard colors, red,
orange, green, blue, yellow and white but will work with some other combinations. The cube must be very
smooth and easy to turn.
Select and run the “MindCuber” software file on the NXT. MindCuber starts by moving the “tilt arm” and
then the “scan arm” as far as it can to determine where they are. The color sensor flashes red during this
process to show that it is running. If there is a Rubik’s Cube in the turntable, MindCuber detects this and
display a message asking you to remove the cube.
When MindCuber detects that there is no cube present, it stops flashing the color sensor and displays a
message asking you to insert a scrambled cube.
You must make sure that the “turntable” is correctly aligned so that its front edge is in the same direction
as the frame since MindCuber is unable to do this itself. Use the left button on the NXT to rotate the
turntable anti-clockwise and the right button to rotate it clockwise. Short presses will rotate by small steps
for fine adjustment. A long press will continuously rotate the turntable for larger adjustments. When the
motor is stopped, the turntable can rotate a little because of the gears between it and the motor. Try to
rotate the turntable very gently by hand. Check that you can rotate it by the same amount each way past
the correct position. The turntable usually only needs to be aligned once each time the program is started
but you can adjust it at any time when MindCuber is waiting for the cube to be inserted.
Place the scrambled Rubik’s Cube in the turntable. MindCuber uses the ultrasonic sensor to detect when the cube is present and starts automatically. It scans the cube a square at a time using the color sensor.
After all 6 faces of the cube have been scanned, MindCuber flashes the color sensor red while it attempts
to determine the colors and then flashes it blue while it works out a solution. The software takes up to 10
seconds to calculate a solution and usually finds one of between about 40 and 45 moves.
Once MindCuber has calculated a solution, it then tilts and turns the cube to solve it. At the end the arms
are moved away and the cube spins and the color sensor flashes green to indicate that it has finished. The
flashing stops when you remove the cube.
The time is displayed continuously in the corner of the screen during and after the solve. MindCuber usually
takes between 2 and 3 minutes for the complete solve process.
MindCuber is now ready for you to insert another scrambled cube to solve.
Tips:
Watch when the cube is tilted to make sure that it tilts over and slides back correctly every time. If it
sometimes tilts back instead of sliding back, make sure that the stickers are placed in the turntable as
indicated in the build instructions to help the cube slide easily. If the cube has particularly sharp edges, you may find that larger stickers help
If MindCuber cannot work out the colors correctly, it rescans the cube automatically up to three times. If it
still fails to determine the right colors, it will move the arms away, continue to flash the color sensor red
and wait for you to remove the cube to try again. If there are bright or changing lights shining on
MindCuber, it can make it harder to sense the colors correctly. Try moving MindCuber away from the lights.
If the scan still does not work well and you can solve one face of the Rubik’s Cube yourself, you can
calibrate the color sensor to match the white on the cube to help. When the red light is flashing red waiting
for you to remove the cube, press the center orange button before removing the cube. MindCuber displays
“Calibrate white” on the screen. Solve the white face of the cube yourself and put the cube into the
turntable with the white face upwards. MindCuber will then scan just the white face and use that to
calibrate the sensor so which may improve scan. This calibration will be used until you re-calibrate or
restart the program.
If the cube is not the standard colors it may also prevent it from scanning correctly.