Transformations in V+, VAL3, and TPP

Sebastian van Delden

USC Upstate

svandelden@uscupstate.edu

V+

Defining Transformations The built-in V+ trans function creates

a new transformation:

trans(X, Y, Z, Yaw, Pitch, Roll)

Related V+ Functions set curpos = HERE The here function returns a transformation that represents the current

location of the tool frame (NOTE: set needs to be used to populate location variables).

decompose curvals[ ] = curpos The decompose function can be used to return the 6 position values.

dx (location) Returns X value of location

dy (location) Returns Y value of location

dz (location) Returns Z value of location

inverse (transformation) Return the inverse of its parameter

Related V+ Functions RX(angle)

Create a pure rotation transformation of angle degrees around X.

RY(angle) Create a pure rotation transformation of angle degrees around

Y. RZ(angle)

Create a pure rotation transformation of angle degrees around Z.

SHIFT(transformation BY x_shift, y_shift, z_shift) Return a transformation resulting from shifting the translation

values of the transformation parameter.

scale(transformation BY factor) Returns a scaled transformation

Applying Transformations Transformations can be multiplied together using a

colon(:) to create a new location. move trans(10,2,30,90,0,0):rx(30):a

ORDER MATTERS: move rx(30):trans(100,0,0,0,0,0)

Make a 30 degree rotation around robot world X and then translate 100 mm down this direction.

I.e. rotation happen around world frame move trans(100,0,0,0,0,0):rx(30)

Translate 100 mm down the original world X, and then a 30 degree rotation

I.e. rotation happen around tool frame

Defining Tool Transformations/Frames The tool frame is

located on the tool flange.

Usually the tool frame is moved to an appropriate location in the tool. Allows for better tool control

tool trans(X,Y,Z,Yaw,Pitch,Roll) X,Y,Z,W,P,R are manually determine by user.

Tool Transformations

IMPORTANT: Always assign the tool transformation before you teach points AND before you visit those points.

All motion instructions after the tool trans declaration use that tool frame.

The tool can be redefined at any point in the program with another tool trans statement

Tool Transformation Example

What is the tool trans for this tool?

Original tool frame on flange

Desired location of tool frame

Defining Generic Frames A coordinate system, or frame, can be

created in V+ by teaching 3 locations An origin, origin. A location on the X axis, x. A location on the Y axis, y.

set f = frame(origin, x, y, origin) The first parameter is where X and Y cross. This

is usually the origin, but you can move this up or down.

More on Frames Be careful when moving to a frame. Consider trying to touch the origin of the

frame in the picture with the tip of tool. move f

Will crash the arm in the box move f:trans(0,0,0,0,180,0)

Will align Zs properly

Approaching and Departing Locations appro(A, 50) or appros(A,50)

Go to a location 50 mm “above” A, where “above” is along the Z axis associated with A

depart(50) or departs(50) Move 50 mm away from the current location along

the location’s Z axis.

VAL3

Defining Tool Transformations/Frames Any number of tool transformations can be

defined as global variables

1. Cursor to “flange”

2. Press “New” Key

- Give the tool transformation a name, for example, “mytool”

Manually Enter X, Y, Z, W, P, R…

Tool Transformation and Motion

Every motion instruction must include a tool transformation as a parameter: movej(somePoint, mytool, motionDescription) movel(somePoint, mytool, motionDescription) movec(viaPoint, somePoint, mytool, motionDescription)

No guesswork!

• Transformation Variable trsf enables to make computation on

Cartesian points• Ex : Approach on point, Shift in pallet, Compose a new point, ….

• 6 numeric field : x, y, z, rx, ry, rz

• If trsf trShift is defined, two possible ways to populate it with values:

trShift={0,0,-100,0,0,0}

or trShift.x=0 trShift.y=0 trShift.z=-100 trShift.rx=0 ...

Defining Transformations

Not possible to make motions on trsf!! Used ONLY for computation on Cartesian !!

POINT ← appro(POINT,TRSF) APPRO computes a Cartesian point related to a point on which is applied a transformation

Apply a Transformation using APPRO

pX

Z tool

X pPick-100

Or: movej(appro(pPick,trShiftz),tGrip,mFast)

Or:movej(appro(pPick,{0,0,-100,0,0,0}),tGrip,mFast)

POINT p POINT pPick TRSF trShiftz NUM nDistance=100 are definedtrShiftz={0,0,-nDistance,0,0,0}

p=appro(pPick,trShiftz)

movej(p,tGrip,mFast)

Transformation Example 1

100

180 12

X

ZpPick 3

movej(appro(pPick,{180,0,-100,0,0,0}),tGrip,mSlow) 1

3movel(pPick,tGrip,mSlow))

2movel(appro(pPick,{0,0,-100,0,0,0}),tGrip,mSlow)

Transformation Example 2

movel(pPick,tGrip,mSlow) 1

1

Z

X

pPick

X

ZpPick

2- 20°

2movel(appro(pPick,{0,0,0,0,-20,0}),tGrip,mSlow)

(Blend =off)

Defining Generic Frames

Importance:

The robot is in production,

The application is working at

full capacity, but ….

Joe is driving the forklift and ...

!!!! DISASTER !!!!!

… one day for re teaching locations..

Except if ...

Frame Creation

Local Coordinate system :

• to make points re teaching easier

• used to duplicate locations

• shift of points in a pallet

Frame Teaching

fPallet

X

YX

Y

World

Axis x

Axis y

Origin

Defined with 3 points to teach :

• Use a precise tool : pointer

• Define this tool as current

• Teach points as far as possible

each other (+ accurate)X

Y

POINTS IN A FRAMETeach points using the frame so that they are created in the tree branch of the frame.

• During teaching coordinates are displayed in frame reference

• For the move instruction, it is not

needed to specify the frame:

movej(pA ,tGrip, mFast)

fPallet

X

YX

Y

World

pA

Setting a Frame in the Program

nError = setFrame(pOrigin, pX, pY, fRef)

Frame to compute(A Pass-by-Reference Parameter)

3 points O, X, Y

Error Code :

0 : no error-1 : ptX too close to ptOrigin-2 : 3 points are nearly aligned

Compose can be used to define a new point in the frame

5080

fPallet

X

Y

Compose(point,frame,trsf) : compute a point shifted

by trsf expressed in frame

X

Y

World

p=compose(pFirst,fPallet,{160,50,0,0,0,0})

movel(p ,tGrip,mSlow)

Using 2 Identical Frames

fRef1X

Y

To use a point with same

coordinates in 2 frames :

• Create a point in each frame

• Teach one of the point

• Copy trsf of point in second one

X

Y

World

fRef2

XY

pRef2.trsf=pRef1.trsf

TPP

Defining the Tool Transformation/Frame The tool coordinate system is defined by

using the frame setup screen or changing the following system variables.

Ten tool coordinate systems can be defined. The desired one can be selected. $MNUTOOL [ 1, i ] (Frame number i = 1 to 10) is

set the value. $MNUTOOLNUM [ group ] is set the used tool

frame number. Three ways to set a tool frame.

Navigate to the Tool Offset Menu Press the MENU key on the teach pendant and then

navigate to SETUP -> FRAMES.

You can define up to 10 tool frames Select the one you want to define and click DETAIL.

SETIND sets the current tool frame.

Choose which method you want to use to define the tool frame

Direct (Manual) Method – just type in the X, Y, Z, W, P, R values

Three Point Method Defines the only X, Y, Z location of the tool

center point (TCP). Teach three points that approach the TCP

from different angles The bigger difference in the angles the better.

Use a stationary point. There is no “built-in” three point method in V+

… Exercise: Figure out how to do this in V+/VAL3

The Three Point Method Idea

Think about the Geometry/Math

TPP walks you through the three point method

The three points to be taught

Six Point Method

Setting the Tool Frame in a Program A taught location can only be revisited if the

active tool frame is the same one it was taught with. The program will generate a run time error if a

different tool frame is active. The tool frame can be changed in the

program using the UTOOL_NUM = … command. To find this, press [INST], then:

Setting the Tool Frame in a Program Set the appropriate

tool frame before the motion instruction

Taught using tool frame 2

Taught using tool frame 1

Defining Generic Transformations/Frames In TPP, you can define “offsets” which can be

applied to any motion command. It can be inserted directly in the motion

command. Example - move to location p[1] with an offset

located in position register 2 (pr[2]):

Step-by-Step Example: Offsets

Recall the previous program a couple slides back:

Let’s add an offset/transformation so that the point P[3] is visited with a -50 Z translation and a 20 degree Yaw rotation (around X).

Defining the Offset in a Position Register.

1) Press Data Key

2) Press |TYPE| (F1) and cursor to Position Reg

Enter the values: 0,0,-50,20,0,0 and press done when finished

Modifying the Motion Instruction

Press Edit key to get back to program and cursor over to the end of the desired motion instruction. Then press CHOICE.

Navigate to Offset, PR[…]

Finish Inserting the Offset P[3] is now visited with an offset of -50 in tool Z

and a Yaw of 20 degrees.

Offset VERSUS Tool_Offset

Offset Performs the transformation w.r.t the world

coordinate system Tool_Offset

There is also a “Tool_Offset” that you can navigate using the menus which performs the transformation w.r.t the tool coordinate system.

Defining Generic Frames Called User Frames in TPP, these frames are defined

and used almost exactly like how tool frames are. Like with tool frames, navigate to Frames:

If you are still looking at the tool frames, press the |OTHER| function key and choose User Frame

Manually Enter in the User Frame data or use one of the built-in methods

Selecting the User Frame

Just go back to your program, and insert the

UFRAME_NUM = …

command similar to how a tool frame is declared in the program.