robotics motion functions alec robertson – department dmf – confidential wonderwyler

RoboticsMotion Functions

Alec Robertson – Department DMF – Confidential

WonderWyler



axis 5 0

Wyler

• Levelling method• no robot error

compensation

• low tool0 accuracy compared to nominal

• innacurate recalibration process

X

Z

Ideal tool0Actual tool0

Key

Y

foot 0°

axis 2 90°

axis 3 0

axis 4,6 0

Wyler spread



Wyler Errors

• Existing process• error 0.9mm at tool0• error 1.5mm at TCP (200, 200, 200)

• Error sources• Placement of sensors and plates (55%)

• Tolerance of plates (35%)

• Stochastic (10%)



WonderWyler

• Improve process repeatability• No axis 1 mechanical components

• No mounting plates

• Highly accurate mounting cube

• Absolute measurement not relative

• Automated via RobComm/RAPID

• tool0 deviation 0.4mm



Main Unit

Left view

Bottom view

Wyler Side

Wyler Front

Control spheres

Mounting track

Mounting track

Control spheres

Mounting track and preload spring to accomodate mounting hook (or have spring integrated into hook )

Mounting hook on robot structure



Prototype

• Step 1• Automate via PC• Serial communication with

LevelMeter• RobComm communication

with S4C

• Step 2• Plug into S4C• RAPID automated calibration

LevelMeter 2000

Sensor A

Sensor B

RS232

RobComm



Axis 1

IRB140

IRB1400

50mm

IRB2400L

IRB2400

IRB6400

IRB6400R

50mm

Left or Right side of robot base

No right angle surfaces

60mm

60mm

Left or Right side of robot base


50mm

50mm

Left side of robot base

Right angle surfaces

Machined surface

Mounting button screwed into existing threaded hole

Mounting hook



Axis 2 [1]

IRB1400Front of arm 2


Back of arm 2


50mm

50mm

50mm

50mm

IRB140

Back of arm 2

Right angle surface on right60mm

60mm IRB2400L

IRB2400

IRB4400

Machined surface

Machined surface Mounting button screwed into existing threaded hole

Mounting hook



Axis 2 [2]

Back of arm 2

Right angle surface on left and right50mm

50mm

IRB6400

Front of arm 2

Right angle surface on left

IRB6400R50mm

50mm



Flange [1]

Left Face

Right Face

Interface Plate

Control spheres

Robot flange holes

Robot FlangeWonderWyler Unit

Control cylinders

Control cylinder

Control pin

Mounting hook



Flange [2]

IRB140

IRB1400

IRB2400L

50mm 63mm 125mm 160mm

IRB2400

IRB4400

IRB6400

IRB6400R

WonderWyler unit

Interface plate

Robot flange

315mm

Voyager



Sensors

57mm

90mm

24mm



Overview

• Operator actions• Base, axis 1, lower arm, wrist,

flange placements

• RobComm/RAPID automation• Input angles via serial port

• Calculate axis adjustments

• Recalibrate resolvers

Base (reference)

g

Lower arm (axis 2)

Flange (axis 3–6)



Procedure

• Connect to serial port on cabinet/robot• Run RAPID Program• Sequence

• Base/Foot

• Axis 1

• Axis 2

• Axes 3–4 on wrist

• Axes 3–6 or 5–6 on flange



Base

• Place WonderWyler on base reference plate

• Measure reference values• Wyler Front (FR)

• Wyler Side (SR)

Wyler Front Reference Value (FR)

Wyler Side Reference Value (SR)

g



Axis 1 [1]

• Split kinematic coupling• Determine axis 1 adjustment

from kinematic coupling geometry (scale factor K) 1 = K·F1 - FR

Wyler Front Value (F1)

Wyler Side Value (S1)


Axis 1 adjustment

WonderWyler kinematic coupling

Axis 2 housing

FootKinematic coupling grooves



Axis 1 [2]

• Retrofit REX• Fit plates to Wyler surfaces

• Machine new plates

• Plate material• Strong enough to withstand

factory abuse

• Low friction to allow sliding of WonderWyler spheres

• Integrated mounting button

WonderWyler unit

Axis 1 plate with 2 grooves

Axis 2 plate with 1 groove

Mounting button



Axis 2



• Connect to Axis 2• Run robot to CalPos2 • Measure absolute values

• Front (F2), Side (S2 )

• Axis 2 adjustment 2 = F2 - FR

CalPos2= (0,0,0,0,0,0)



Axis 3 - All Robots

• Connect to flange • Run robot to CalPos3 • Measure absolute value

• Front (F3)

• Axis 3 adjustment 3 = F3 - FRWyler Front Value (F3)


CalPos3= (0,0,0,-90,0,90)



Axis 4 - All Robots

• Run robot to CalPos4• Measure absolute value

• Front (F4)

• Axis 4 adjustment 4 = F4 - SR



CalPos4= (0,0,0,-90,90,90)



• No need to remove tool• Connect to wrist plate• Run robot to CalPos3 • Measure absolute value

• Front (F3)

• Axis 3 adjustment 3C = mass * compliance

3W = F3 - FR

3 = 3W - 3C

Axis 3 - Large Robots

CalPos3= (0,0,0,0,0,0)

3c

no load

sag due to load





Axis 4 - Large Robots

• Measure absolute value• Front (F4)

• Axis 3 adjustment 4C = mass * compliance

4W = F4 - FR

4 = 4W - 4C Wyler Front Value (F3)




Axis 5 and 6 - All Robots

• Run robot to CalPos5• Measure absolute value

• Front (F5), Side (S5)

• Axis 5, 6 adjustments 5 = F5 - FR

6 = S5 - SRWyler Front Value (F5)


CalPos5= (0,0,0,0,0,0)



Quality Check

Quality Check

Parallelogram Effect on Axis 3 Error

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

-60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60

Axis 2 (degrees)

Axi

s 3

Err

or

(Deg

rees

)

Axis 3 Error (with offset adjustment)

Axis 3 Error

Wyler Measured (24-12401)

Parallelogram Model

3=03=+13=-1

Parallel Arm Length OK!

Parallel Bar Length OK!

Predicted Reorientation OK!



Obsolete Methods



Axis 1 [1]

• Use mechanical fork• Trim robot via RAPID

• Acceptable accuracy

Hollow cylinder to match 10 pin on axis 2 housing

Axis 2 housing

Base/Foot/Axis 1 housing

10 pin to fit hole in base reference plate

Calibration tool



Axis 1 [2]

• Improve existing design• Connect axis 1 rocker arm• Measure absolute values

• Front (F1), Side (S1 )

• Axis 1 adjustment 1 = F1 - FR

arm

Wyler front

hinge Wyler Front Value (F1)




Interface Plate [3]

Control spheres

Machined grooves

Robot FlangeWonderWyler Unit

Control spheres magnetically attach (kinematic coupling) to control cylinders

No Interface Plate

robotics motion functions alec robertson – department dmf – confidential wonderwyler

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