Appendix I: Example Performance Level Evaluation For The Pfdd - Brooks PreciseFlex DD 6-Axis Service Manual

Brooks Automation
Part Number: 628651 Rev. A
Appendix I: Example Performance Level Evaluation for the
PFDD
Example Workcell description: A PFDD4 moves 100-gram plastic trays from storage racks to an
instrument and back to the storage racks. Gripper is an electric parallel jaw gripper with maximum
23 N of gripping force for plastic trays and is spring loaded so it will not drop trays if power fails.
Robot motion is programmed with approach point 50 mm above the instrument tray and final motion
into instrument is made at 50 mm/sec. Lowest storage rack position is 50 mm above table surface.
Normal Operator Interaction with robot:
Teaching locations in workcell by hand guiding or teach pendant. Maximum robot forces under
manual control from PFDD Table 1 are 105 N. Pausing robot and removing racks from workcell with
safety interlocks in workspace. Robot is stopped.
Possible Low Frequency (rare) Interaction with Robot:
Untrained operator reaches into workcell while robot is moving and robot collides with operator.
Maximum free space collision force from PFDD Table 1 is 182 N, which is below free space collision
for 500 ms maximum of 280 N. Untrained operator reaches into workcell while robot is moving into
instrument tray and hand is trapped between robot and instrument tray. From PFDD Table 1 max
trapping force in downwards Z direction at 60 mm/sec (10% of max speed of 600 mm/sec) is 77N.
Performance Level: From the above, based on ISO 13849-1:2006:
S is S1, as possible operator collision forces will not injure operators.
l
F is F1 as normal operation does not involve collisions with robot.
l
P is P1 as the robot does not make unexpected motions
l
So PL is "a," and even a Category B controller is sufficient given the low speeds and small possible
collisions forces involved which cannot injure an operator. (See 5.2.3 under
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Appendix I: Example Performance Level Evaluation for the PFDD

Example PF400 Workcell: Courtesy of Biosero
Appendices
EN/ISO 10218-1:2011).
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