Rotatory conveyor synchronisation

    Hello Everyone,


    We are doing form pouring project with Kawasaki ZX165 robot and E02 controller, so our mold is on rotary conveyor and conveyor diameter is 11.35 meter. We have total 15 number of station on rotary conveyor and we are using Posital make incremental encoder.


    We done the encoder wiring with 1SQ board and checked the encoder feedback, it coming properly.


    We checked Conveyor operation manual and according to manual input the data but still my robot not track properly, I have some doubt regarding conveyor synchronisation.


    1. How to calculate the resolution for Rotatory conveyor??? (i already check manual but in the manual no calculation formula or method mentioned).

    2. In Environment data other details also required i.e. (Maximum speed, Maximum position, Gain for conveyor speed Bias, etc), so how to calculate this data???


    Request to everyone, If anyone having idea related this issue, please support.


    Thank you in advance.

    • AD

    Kawasaki themselves can also offer assistance if you don't get any responses offered by other members, whom dedicate some free time (without charge) here at Robot Forum, you of course may need to pay for that assistance, but if you are getting paid for the job, then you wont be out of pocket by at least contacting them.


    I suspect setting the conveyor parameters is similar to setting up a rotary positioner on an external axis which just needs some number crunching based on your installation.


    In effect, the conveyor is a 'flywheel' attached to the end of a central motor and if your encoder is fitted to the motor then:

    - How many bits are provided by the encoder for one revolution of encoder travel.

    - How many revolutions of the encoder does it take to rotate the conveyor one revolution.

    - This will provide how many bits in total per one revolution of the conveyor.

    - Work out the circumference of the conveyor (radius from motor to centre of conveyor).

    - Divide the circumference by how many bits per one revolution of the conveyor.

    - This should provide bits/mm for the encoder setting.

    - If you have 15 stations you then have 24 equal positions around the circumference of the conveyor.

    - So divide the circumference by 15 and you will have the distance in mm of each station centre.

    - You should then have equal distances between each station centre then.

    - So if the bits/mm is correct, you should be able to find each station based on the encoder value.


    I believe the above will put you in the ball park, ages since I did any of this, so I may not be 100% accurate.

    Dear sir,


    First of all thank you for your reply,


    -Encoder mm/bit is calculate according to the manual formula = distance travel by conveyor (mm) divide by

    (Encoder value after the motion (bit) - encoder

    value before the motion (bit))

    -I checked encoder bit value by using Where25 command.

    - Conveyor radius is 5523mm.

    - One station to another station distance is 1940mm.


    For your reference I attached one drawing layout, please check once and give your feedback.


    Thank you for your reply.

    Dear Kawasaki sir,


    Please help to solve conveyor tracking issue,


    I am badly stuck in middle of this project.


    Thank you in advance.

    So what are your values for each point I wrote?

    Quote from kwakisaki

    So what are your values for each point I wrote?

    Dear Kawasaki sir,


    - How many bits are provided by the encoder for one revolution of encoder travel :- Encoder PPR (1-16384), this data provided by encoder OEM.

    - How many revolutions of the encoder does it take to rotate the conveyor one revolution ;- 269110597 bit.

    - This will provide how many bits in total per one revolution of the conveyor:- according to the formula

    = distance travel by conveyor (mm) divide by

    (Encoder value after the motion (bit) - encoder

    value before the motion (bit), we get resolution 4.264544 mm/bit

    - Work out the circumference of the conveyor (radius from motor to centre of conveyor):- diameter of conveyor is 11537, so circumference is πxdiameter= 36223.04.

    - Divide the circumference by how many bits per one revolution of the conveyor.

    - This should provide bits/mm for the encoder setting.

    - If you have 15 stations you then have 24 equal positions around the circumference of the conveyor.

    - So divide the circumference by 15 and you will have the distance in mm of each station centre:- 2415.53mm

    - You should then have equal distances between each station centre then.

    - So if the bits/mm is correct, you should be able to find each station based on the encoder value.


    Dear Kawasaki sir,


    According your all point, i input all the data but when I try to track the robot it's not follow the conveyor.


    Sample program for conveyor tracking :-


    Sir,

    If any point is wrong from my side, please suggest.

    Who has installed the rotary conveyor?

    What is driving the conveyor motor?

    Is the motor coupled to the conveyor via a gearbox at all?

    Where is the encoder mounted to?

    What tests/checks have you made to ensure your values are correct?

    What settings have you actually made?

    Are you getting any errors?

    What is actually happening aside from 'it doesn't track'?

    Have you read the manual and confirmed things in line with the documentation?

    There is setup and programming procedures, have you followed them?


    When you are looking for assistance, please provide more details as no-one reading your posts are seeing what you are seeing, as they are not there, so if you post, make sure it is full of as many details as possible.................the more details the better.

    Dear Kawasaki sir,


    First of all, Thank you for your reply.


    Requested details is below,


    - Who has installed the rotary conveyor:- Third party system integrator install conveyor.

    - What is driving the conveyor motor:- Siemens Induction motor drive the conveyor and controlled by siemens VFD.

    - Is the motor coupled to the conveyor via a gearbox at all:-Yes, Motor is couple with the gearbox and gear ratio is 1:111.

    - Where is the encoder mounted to:- Encoder mounted at the center of conveyor and Encoder is open collector type (Incremental) (Encoder make:-POSITAL).

    - What tests/checks have you made to ensure your values are correct:- Mark the point at the conveyor measure the fixed distance manually and then reset conveyor axis data and run the conveyor till the marked point match the manual data and axis data, found 20-25mm variation.

    - What settings have you actually made:- setting i made that is in attached photo.

    - Are you getting any errors:- No, whenever I tried to track the conveyor at that time robot move opposite direction of conveyor moving and move till its maximum axis data.

    - What is actually happening aside from 'it doesn't track:- Whenever i tried to track the conveyor robot not follow the conveyor, the robot is left behind and the conveyor overtakes it and if we increase the robot speed then robot overtake the conveyor.

    - Have you read the manual and confirmed things in line with the documentation:- I have conveyor synchronization manual, according the manual only I insert the data, only I have doubt about how to calculate 1. Gain for conveyor speed bias? 2. Ineffective pitch?

    - There is setup and programming procedures, have you followed them:- According to the manual procedure only I did the programing.


    Dear Sir,


    I am trying to give all the information but rather than if I missed something please ask, I will try to provide all the details.


    once again thank you so much for your reply and support.

    Please describe process of conveyor operations in detail?

    What is application and walk through step by step of operation requirement?


    Who enabled conveyor synchronization option?

    - Was it already enabled by Kawasaki (supplied) or has someone else done it?

    - If someone else has done it, have they done it correctly with Kawasaki assistance?


    I always advise, before application to test connection is all working first without any calculation:

    - After conveyor synchronization option is available and installed and before characteristic settings.

    - Connect encoder to robot.

    - Leave encoder uncoupled so you can rotate encoder by hand.

    - Rotate encoder positive and negative to confirm increase and decrease in values happen.

    - This ensures controller is registering pulses.


    Then to make very small tests based on encoder shaft circumference and then a known flywheel:

    - Make small mark on shaft as marker for 1 revolution visual.

    - Measure shaft diameter and calculate circumference of encoder shaft.

    - So 1 revolution of encoder shaft = circumference distance of encoder shaft.

    - So 1 revolution of encoder bits = 1 revolution of encoder shaft circumference distance.

    - Set calculation values and test 1 rotation of the encoder matches to CONV1 value.

    - Tweak the value a little if there is a variation.

    - Then attach a known circumference flywheel to it and repeat.

    - This way you know and prove the calculations are correct.

    - Then I would couple it up to the application and then set it up again.

    - This ensures the base settings are correct.


    What did you do as an initial setup to confirm things, did you carry out any tests like I have said above?


    It could be your initial settings need tweaking a little, as your values don't seem correct to me.

    Speculation on my part, as I do not have access to the physical environment and all information.


    What circumference are you tracking for the robot?

    - the conveyor is a set width, so you have an outer, inner and centre circumference.

    - from memory, I always use the centre circumference (ie the middle of the conveyor).


    Is it tracking in a circular plane - ie following the circumference as opposed to linearly?


    I could do with seeing a video of what is happening, which shows:

    1. Robot and TCP

    2. Conveyor and 'marked' position you are starting to track from before robot moves.

    3. Then robot and TCP moving to 'marked' track point and during tracking.

    4. Then robot and TCP moving away after tracking finished.


    Please respond to ALL my questions, as I don't wish to keep having to repeat myself.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account
Sign up for a new account in our community. It's easy!
Register a new account
Sign in
Already have an account? Sign in here.
Sign in Now