Mecademic Meca500 R3, Programming Manual

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10 Programming manual for Meca500 (for firmware 9.2.x)
BASIC THEORy ANd dEfINITIONS
Figure 7: By crossing singularities, the Meca500 can execute longer linear movements
(a) A
↔
B via Z1, only possible with
AutoConf
(1)
(b) C
↔
D1 via Z2, with
AutoConf
(1) (c) C
↔
D2 via Z2 and stationary
re-orientation, with
SetConf
(1,1, −1)
Figure 8: Crossing a wrist singularity with
AutoConf
(1) or with a desired posture configuration
Similarly, consider Figure 8 b , where AutoConf is enabled, the robot starts from position C, passes
without any interruption through the singular configuration Z2 (where θ
1
= θ
2
= θ
3
= θ
5
= 0°, θ
4
= 90°,
θ
6
= −90°) and goes to robot position D1, all with a single
MoveLin
command. In the process, the
robot changes posture parameter c
w
from −1 to 1. However, as shown in Figure 8 c , if you execute
SetConf
(1,1,−1), then request the robot to move to the end-effector pose D1, starting from robot
position C, the robot will execute the
MoveLin
command, but when it reaches configuration Z2, joint 4
will rotate −180° and joint 6 will rotate 180°, at the same time while the end-effector will remain
stationary. After that, the robot will continue its linear motion and reach the robot position D2 (which
corresponds to the same pose as D1).
In contrast, since shoulder singularities are much less frequent, yet much more complex to handle, the
robot can currently cross them only in AutoConf. More precisely, when executing a linear move, the
robot will never stop at a shoulder singularity to reorient its joints 1, 4 and 6 while keeping the end-
effector stationary. Thus, the motion sequence shown in Figure 9 a cannot be executed with a single
MoveLin* command, whatever the state of posture configuration selection. However, in AutoConf, you
can cross a shoulder singularity, as shown in Figure 9 b .
To experiment with shoulder singularities, simply execute
SetTRF
(0,0,−70,0,0,0), to bring the TCP at the
wrist center, then
SetWRF
(0,0,0,0,0,0), and then bring the TCP to a position where its coordinates x and y
are zero.