1.) Introduction

An HC Series Robot will have a Torque Sensor on the output side of every axis gear reducer.  These need to be calibrated when the robot is first set up and occasionally during the life of the robot as their output values can drift slightly due to changes in temperature, hard stopping situations, changes to the robot mounting, etc.

2.) Overview

Calibrating the Torque Sensor Origin Position requires special robot loading and posture in software version earlier than YRC1000 System Version YAS 2.95 or YRC1000micro System Version YBS 2.32.  Software versions later than those can be calibrated with any posture as described below.

Calibrating the Torque Sensor Origin Position requires the controller to be in SAFETY SECURITY MODE.

The calibration process involves three main steps:

1. Select a Tool Data File with the correct tool and loading condition.
2. Move the TCP of the selected tool a minimum of 5mm.
3. Calibrate the Torque Sensor Origin Position.

Before starting the procedure below, it is important to note that the position at which the user sets the torque sensor origin can significantly impact the performance of safety functions. Setting the torque sensor origin at different locations will result in varying force readings by the robot. Conduct a risk assessment prior to implementing a torque sensor calibration.

3.) Procedure for Standard Pendant

1.  Select a Tool Data File

a. The calibration must be performed with the correct Tool Data File for the tool and loading condition that is currently on the robot.  Calibration with an incorrect Tool Data File can cause the controller to calibrate to incorrect values and lead to PFL errors and incorrect Pull Back behavior.

b. Press and hold the SHIFT key and then the COORDINATE key to bring up the TOOL NO. SELECT list.  Cursor to the correct Tool Data File and press SELECT.  The selected Tool Data File number will be shown in the upper right-hand corner of the display.

2. Move the TCP of the selected tool a minimum of 5mm

a. Upon changing a Tool Data File, the robot controller will temporarily mute any errors that can be caused by improper tool conditions until the TCP has moved at least 5mm.  Calibrating without moving the robot a minimum of 5mm may cause the calibration to be performed with the previously selected tool data and result in incorrect calibration.

3. Calibrate the Torque Sensor Origin Position

a. Select SAFETY FUNC. and then select TORQUE SENSOR ORG POS

4. Select EDIT to display the SELECT ALL AXIS icon.

5. Select SELECT ALL AXIS to display the confirmation window.

6. Select YES to complete the calibration.

4.) Procedure for Smart Pendant

1. From the Smart Pendant home screen select the side bar.

2. Upgrade Security to “Safety”

3. Click on “Safety Settings” and then select “Torque Sensor Calibration”

 
4. Once the torque sensor calibration tab opens, ensure that the correct tool is selected.

a. The robot will judge its current forces based on the mass that is recorded in the tool file, so it is important to ensure that the correct tool file is selected, and the tool file contains the correct tool mass
b. Upon changing a Tool Data File, the robot controller will temporarily mute any errors that can be caused by improper tool conditions until the TCP has moved at least 5mm. Calibrating without moving the robot a minimum of 5mm may cause the calibration to be performed with the previously selected tool data and result in incorrect calibration.

 
5. Once the user has confirmed the tool data is correct, select on “CALIBRATE ALL TORQUE SENSORS”.

6. The Smart Pendant will ask the user if tool data is correct. If this is true, select “YES, CALIBRATE”.

 
7. Select “READBACK”.

8. Select “WRITE”.

 
9. The user can now select “VERIFY CALIBRATION” to view the “Force/Torque Watch” screen to verify that forces have now settled near 0N.