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1 Line Track Description

Linear tracking is the chain speed tracking we often hear, mainly used to deal with the picking and placing of moving workpieces, the speed and direction of moving objects to the robot, the robot controller after algorithm processing, so that the robot moving speed and moving objects are the same, so as to ensure that the robot and moving objects are relatively stationary, and finally achieve accurate pick and place.

Linear tracking not only allows the robot to follow a linear running mechanism, but also allows the robot to follow a circular motion mechanism.

Figure 1 Linear motion mechanism tracking

Figure 1 20 Ring kinematics tracking

2 What Meaning

Linear tracking, literally expressed clearly.

Linear: Refers to linear or circular motion.

Chase: The robot walks after a linear kinematic structure.

Track: Refers to the trail of a moving mechanism walking.

The robot runs after the sports mechanism, and wherever the movement mechanism runs, the robot follows in time.

3 How to use

Linear tracking involves independent motion mechanisms outside the robot, such as a belt conveyor, if the robot wants to run with the belt conveyor, the robot must know the speed of the belt conveyor, and the conveying speed can be calculated by the ratio of the number of rotary encoder pulses to the actual conveyor data.

First, set the encoder parameters in the FANUC robot teach pendant, as shown in the following table:

Second, set the linear tracking related parameters, as shown in the following table:

Finally, write the linear tracing program, the programming steps are as follows:

1. Create a new master program (usually named job) to open the tracking encoder

2. Move the robot to the home point or wait point

3. Wait for the trigger signal when the workpiece comes

4. Record the value of the conveyor encoder (need to record immediately after the trigger signal to ensure that the robot and the conveyor are synchronized)

5. Store the encoder value

6. Select the linear trace boundary

7. Execute a linear tracking program (usually named tracking)

8. Exit linear tracking

9. Mission accomplished

Example of how to use the FANUC robot linear tracking function:

Main Program Job:

LINE[1] ON Note: Turn on linear tracking and the encoder enables Turn on Encoder

LBL[1] Note: Call the subroutine M0250021 move the robot to the home point or wait point

CALL M0250021

LBL[2] Note: Wait for a part detect trigger

WAIT DI[32]=ON

Note: Read the line count and rate for the output encoder

LINECOUNT[1] R[1] Note: Read the line count and rate for output encoder rate

LINERATE[1] R[2] Note: Determine whether the conveyor line is moving forward based on the encoder rate Make sure the conveyor moves fwd

IF R[2]<0, JMP LBL[2]  Note: Set the linear tracking progress number trigger value Store the trigger value

SETTRIG LNSCH[1] R[1]  Note: Select a boundary set

SELBOUND LNSCH[1] BOUND[1]  Note: The action command in the execution subroutine MO250022 Move to track the conveyor

CALL MO250022 

JMP LBL[1]

Subroutine M0250021 (back to origin)

J P[1] 100% FINE 

Subroutine M0250022 (action instructions during tracking)

L P[1] 800mm/sec FINE 

WAIT .50(sec) 

L P[2] 800mm/sec FINE

L P[3] 800mm/sec CNT100

L P[4] 800mm/sec CNT100

L P[5] 800mm/sec FINE

C P[6]

    P[7] 800mm/sec FINE

C P[8]

    P[9] 800mm/sec CNT100

C P[10]

    P[11] 800mm/sec FINE