Locator Tutorial: Setting up Locator to work with UR robots

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Users are strongly recommended to read Locator Tutorial: Introduction prior to installation of specific robot interface

1. Prerequisites

Prior to setup, please ensure that your UR controller meets the following criteria:

- CB3.1 or E-series Controller

- System version 3.2 and higher

Click Menu -> About to verify your controller System Version (see figure below):


Locator Setting Up Guide About 2.png

2. UR Controller Setup

2.1 Set IP Address of Ethernet Port

The first step of the process is to configure the IP address of the Robot Controller.

Using the Teach Pendant, press Menu -> System -> Network:

Amend the IP Address and Subnet Mask to match the network configuration of the Vision Controller running Locator and click Apply:


Setting UP Guide Locator URCap Network.png


3. Locator UR Cap Setup

The Locator UR Interface is available as an URCap and three basic program templates. All of these files need to be copied to the Robot Controller.

As the first step, URCap needs to be installed. Extract the Locator URCap archive (.zip file) to the USB stick and plug it into the Teach Pendant.

Press Menu -> System -> URCaps:


Setting UP Guide Locator URCap Active.png


Select the Locator URCap file from USB and click Open:


Setting UP Guide Locator URCap Installation 1.png


Locator URCap should appear in the list of active URCaps. As usual, Restart is needed in order to enable proper functionality of newly installed URCap.


Setting UP Guide Locator URCap Installation 2.png


After restart, Locator URCap should be ready for use:


Setting UP Guide Locator URCap Installation 3.png


As the last step before Calibration, copy the LocatorTemplate.urp progrm from USB Stick to the Robot Controller:


Setting UP Guide Locator URCap Load Program.png


4. Calibration

Robot Camera Calibration is a crucial step in Locator configuration. Accurate calibration guarantees that object positions will be calculated directly in Robot Base coordinates.

Photoneo Robot Camera Calibration for URCap is configured to search for the sphere object, which radius is known. Usually, Ping-Pong or Snooker ball is used for this purpose. Sphere object can be attached to the gripper using peg, suction cup two-finger gripper or another method. The pose of the ping pong ball is not important (doesn't need to be in axis) the only condition is that is should be mounted firmly so it does not move during transitions between waypoints and it is visible from the scanner in each waypoint.

NOTE: Tool Point setting does not affect the calibration process, therefore, it is not necessary to clear tool pose configuration before starting the calibration.

4.1 Robot - Camera Calibration

Mount the Scanner firmly, ensure that the scene is properly captured from the final scanner position and open the Calibration tab on the Installation page:


Setting Up Guide Locator UR Calibration Step 0.png


As the first step set the IP address of Vision Controller and press the Connect button to establish a connection to the Calibration Tool:


Setting Up Guide Locator UR Calibration Step 1 up.png


As the second step of the calibration insert and set Sphere radius (Standard Ping Pong Ball = 20mm, Snooker Ball = 26.25mm):


Setting Up Guide Locator UR Calibration Step 2.png


The third step requires Scanner ID to be set. Both old & new notations are supported. (Old notation example: 1703001 / New notation example: 2018-03-001-LC3)


Setting Up Guide Locator UR Calibration Step 3.png


You are now ready to start adding calibration points. Hold the Enable button and manually or use the Jog menu to move the robot to the first calibration pose. The recommended procedure is to cover all four corners of the scanning volume/bin + two positions in the center of the scanning volume. Change the orientation of the tool in all axes to achieve a wider range of input values.

Press the Capture button to trigger the scan and store the current calibration position. Repeat the same procedure for all 6 calibration points:

NOTE: If calibration ball has not been detected properly or the calibration pose is too close to existing one a popup window notifies the user that calibration point needs to be changed and recaptured!


Setting Up Guide Locator UR Calibration Step 4.png


If all 6 points have been added successfully it is a time to calculate calibration matrix and store result to the scanner. Press Calibrate to finalize the calibration procedure:

NOTE: If calibration error is too high it is necessary to repaet the whole calibration with different calibration waypoints!


Setting Up Guide Locator UR Calibration Step 5.png


4.2 Tool Configuration

After finalizing Robot Camera calibration it is necessary to configure the Tool Point.

Browse to Menu -> Setup -> Frames and select the tool frame you want to use within your program.


Setting UP Guide Locator URCap Z Tool 1.png


Set the X,Y,Z coordinates which denote the position of the tool point of the current gripper with respect to the flange:


Setting UP Guide Locator URCap Z Tool 2.png


5. Runtime

5.1 Reteach Application poses

Once the Robot-Camera and Tool calibration processes have been completed, application poses needs to be retaught. Prior to starting this process, please ensure that you have selected the correct Tool Frame.

Go through the LocatorTemplate program and reteach Home Start, End + Placing positions using the standard procedure as shown in the figure below:


Setting UP Guide Locator URCap Set Position Small.png


5.2 Locator Configuration

Gripper commands must be implemented by the user.

Replace the following comments in the UR Script code by specific commands for attaching the object to the gripper:

Setting UP Guide Locator URCap Gripper Attach.png

Repeat the same step with the gripper Detach command:

Setting UP Guide Locator URCap Gripper Detach.png

Locator URCap always works in Multiple Result Mode. The parameter in locator_trigger(num_of_results) command specifies how many results should locator return from a single scan:

EXAMPLE: PLCF Stop Criteria is configured to Total time 20000ms. Let's assume that Localization finds 32 objects during this period. Locator Best Result Selector is set to Max X criteria. Locator receives 32 results from localization, sorts them according to the X coordinate and transmits 20 top results to the URCap. URCap Receives 20 results and starts picking objects one by one. If only 15 objects are found by Localization, Locator transmits 15 results to the URCap even despite the fact that the requested amount was 20.

Setting UP Guide Locator URCap Num Of Results.png


When picking objects, it is recommended to approach the object linearly. The parameter in get_coordinates(z_axi_offset) specifies the approaching height. The Approaching height is always specified in milimeters.


Setting UP Guide Locator URCap Z Offset.png


5.3 Run Locator

You are now ready to run the program. Switch to T1 mode and select 10% speed; this option is recommended for safety reasons.

Ensure that you are ready to stop the motion execution immediately if something goes wrong.

Select the LOC_SINGLE/LOC_MULTIPLE program or another program which you have prepared your own.


[[File: ]]

If everything is working correctly, you should that the scan has been triggered, the result from Locator has been transmitted to the Robot Controller and the robot is approaching the object.