Installation manual

Chapter 6 Programming
6-21
６．４．２．２ Singularity Avoidance Motion
Singularity avoidance algorism in PA10 customized on the basis of the SC
(singularity – Consistency) method discoursed by Professor Tsumaki, Tohoku
university. Its outline is explained below.
If needed exceeding velocity to any axis during RMRV control, the SC method –
the algorism – lowers the tip velocity and maintains its position and posture. During
RMRC control, in PA10, the operation is always controlled by the SC method. If any
axis exceeds the rated velocity, the tip velocity is decelerated without any alert. It
is not good for the operations needed to maintain velocity.
Conditions Contents
Wrist Singularity
W1 axis angle 0
singularity
If the W1-axis passes through around 0 degree, the E2 and the
W2-axis are laid in a straight line. It creates an enormous reverse
velocity command.
To previously find this singularity, the W1-axis angle is always
observed. If entering into the range designated by the parameter, a
limit velocity defined by the SC method is lowered. The lowering range
is designated in the separated section “Parameter.”
(As the result of lowering a limited velocity, the arm tip motion velocity
is affected. But, the position and the posture are maintained.)
Shoulder Singularity
W1 axis position
singularity
If the W1-axis locates around the S1-axis position, it is needed to
actuate the S1-axis to alter the posture. The low velocity S1-axis
becomes the standard for motion velocity.
To previously find this singularity, W1-axis angle is always observed.
If entering into the range designated by the parameter, a limit velocity
defined by the SC method is lowered. The lowering range is designated
in the separated section “Parameter.”
(As a result of lowering a limit velocity, the arm tip motion velocity is
affected. But, the position and the posture are maintained.)
Elbow Singularity
E1 axis angle 0
singularity
If the E1-axis passes through 0 degree, it creates an enormous
velocity command for the E1-axis.
By restricting the arm movable range in the RMRC control, this
singularity can be avoided. It stops in error with “exceeded arm length
(*1).”
The singularity avoidance processing acs avoiding an undesirable emergency
such as arm hazardous motion. If arm motion is in teach and playback mode, it
is most important NOT TO TAKE those positions and posture.
Remark