| Comments on CHRONO example robot_anthrop_learn.r3d |
| Perform motion of a typical 6-DOF robot |
| What to do: load the file, open the control panel, press the play button on the animation timeline (watch at least 6 seconds of simulation!). Be sure that time slider is at frame 0 (beginning) when you load the project. |
Here you can see the simulation of a 6 degrees-of-freedom (6DOF)
robot, a typical manipulator which is used in many factories as a
device for painting, welding, etc.
Note that the robot is in 'learn' mode, that is, its motion
does not happen because the 6 motors are moving it, but rather because
its end effector (ex.the welding torch) is 'pulled' by a reference which
moves in space, hence obtaining an inverse-kinematic movement.
In fact, if you open the property window of the 6 motors ('motor link'
objects in 'System' level), you see that their 'learn motion' flag is ON,
meaning that they are switched off and they just record their rotation
in the 'a(t) recorder' ChFunction.
By the way, since motors are in 'learn motion' mode, how is this device moved?
Note that there is a 'lock for teach marker' link in System level, which constrains
the position of the tool tip to a moving marker. Hence the moving marker,
performing as a 'teacher' which pulls the robot arm, is in 'ground BODY', and
you can open its property window to see how its motion has been set in x,y,z
space by means of three ChFunctions of type 'Sequence'.
Interesting remark for engineers: after you performed 6 seconds of this simulation,
the motors have learnt their rotation, so you could go back to the beginning
of the simulation and do the following: set 'disabled' ON for the 'lock for teach marker' flag,
set 'learn mode' OFF for the six 'motor link' objects. Than play simulation again,
and you see that robot motion is the same (but this time is imposed by motors in
joints, so you can use Probes to record the needed torques and speeds).
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