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16. Calibrate legs
To adjust the legs exactly, use the programme "Terminal" (if you work with the Windows operating system) or alternatively, the Arduino IDE Terminal.
The aim now is to adjust the legs into an exact basic configuration. When assembling the mechanics, you will not be able to bring the legs 100% into the basic
configuration due to the teeth of the servo disks and the mechanical tolerances. You can use this tool to compensate for these deviations.
Figure 69 shows how the basic configuration should look for each leg.
The fictitious red lines show how to align the leg. The thigh "femur" must be aligned so
that it is parallel to the floor.
The tibia is perpendicular to the floor and makes a 90° angle at the thigh.
If the robot is placed on a flat surface with a mounting aid as shown in the illustration,
the distance between the table and the centre of the M3 cross screws can easily be
measured with a ruler. The angle can also be easily checked with a ruler by using it as
an angle as shown in the illustration. The ruler stands with the short edge on the table
and the long side must coincide with the vertical red line.
Figure 70 shows a ready mounted leg in the basic position. Ideally, the red line would
run exactly in the middle of the screw heads. Since the servo disks do not allow this
due to the toothing and the mounting tolerance, it may be slightly off the mark on some
legs. You can now correct this with the calibration.
Use a mounting aid:
Our mounting aid is ideal for calibrating the legs.
The mounting aid is available as a 3D model for download at www.conrad.com under the product. For printing you need a suitable 3D printer. Alterna-
tively, you can of course also use any other base such as a pot, a sturdy box or similar. It is important that the robot stands stable on it and does not
wobble; the legs must not be obstructed in the movement.
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Figure 69
Figure 70
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