This article describes how to perform eye-hand calibration for a three-axis Robot in an Eye-to-hand scenario.

1. Pin Tool Contact-Point Calibration

1.1 Preparations Before Calibration

Before performing eye-hand calibration, complete the following preparations:

(1) Complete the hardware setup of the 3D Vision Guidance Kit

Please refer to 3D Vision Guidance Kit Hardware Setup to complete the installation and connection of the Robot, Camera, and IPC

(2) Create a Project and a task

Please refer to Project Operation Guide and Task Operation Guide to create a Project and a task.

(3) Complete Camera connection and parameter tuning, then configure it in the task information

Please refer to Camera Connection and Parameter Tuning Guide to connect the Camera, perform camera imaging quality adjustment, verify Camera accuracy, and configure it in the task information.

(4) Complete Robot communication configuration

Please refer to Robot Configuration and Communication Operation Guide to establish communication between the Robot and PickWiz.

(5) Prepare the materials required for calibration

• Please ensure that the Calibration Board is flat and clear, with no obvious scratches, dirt, bending, or deformation

• If the calibration method is random pose sampling calibration, please ensure that the Calibration Board is placed on the work platform and is within the Camera field of view.

1.2 Calibration Information Configuration

Go to the eye-hand calibration interface, click Add Eye-Hand Calibration, and enter the calibration information configuration interface.

• Calibration Name can be used to name the current calibration configuration

• Calibration ID is used by the Robot to switch calibration configurations

• Camera is the IP address of the currently connected Camera

• Camera Brand is the brand of the currently connected Camera

• Robot Type must be consistent with the Robot type in Robot Configuration

• For Camera Installation Method, select Eye-to-Hand

• For Calibration Board Type, select the current Calibration Board type

A suitable Calibration Board is mainly determined by the Robot type and Camera height. Please select an appropriate Calibration Board according to the actual application scenario and the table below.

Robot Type	Camera Mounting Height	Select Calibration Board
6-Axis Robot	Below 0.5 m	A6 Multi-Concentric-Circle Calibration Board
	Below 1.5 m	A5 Multi-Concentric-Circle Calibration Board
	1.5 m -- 2.5 m	A4 Multi-Concentric-Circle Calibration Board
	Above 2.5 m	A3 Multi-Concentric-Circle Calibration Board
3-Axis/4-Axis Robot	Below 0.5 m	A6 Multi-Concentric-Circle Calibration Board
	Below 1.5 m	A5 Multi-Concentric-Circle Calibration Board
	1.5 m -- 2.5 m	A4 Multi-Concentric-Circle Calibration Board
	Above 2.5 m	A3 Multi-Concentric-Circle Calibration Board

• For Calibration Method, select Pin-Tip Touch Calibration

• If the Robot has a corresponding calibration program and needs to run it to send the pose to PickWiz while sampling the Calibration Board, then for Get Coordinates Online** select Yes; if the Robot does not have a corresponding calibration program and the Robot Tool pose must be entered manually while sampling the Calibration Board, then for Get Coordinates Online **select No.

1.3 Checks Before Calibration

• Ensure that the Robot base is securely installed

Before performing eye-hand calibration, carefully check the installation of the Robot base. If the Robot base is not securely installed, the Robot may shake noticeably during movement, affecting Robot accuracy and thus the calibration results.

Check whether the Robot base installation meets the requirements as follows:

First, the surface on which the Robot base is installed must be flat and clean;

Second, operate the Robot to translate or rotate over a large range at 100% speed and observe whether there are signs of shaking. If shaking occurs, readjust and secure the Robot base to ensure that no displacement or tilting occurs during Robot movement;

Third, check whether the Robot body and base are tightly connected, and tighten the screws to prevent loosening.

• Ensure that the Camera and its bracket are securely installed

Before performing eye-hand calibration, carefully check the installation of the Camera and its bracket. If the Camera and its bracket are not securely installed, Camera imaging quality will be affected, which in turn will affect the calibration results.

Check whether the Camera and its bracket installation meets the requirements as follows:

First, check whether the Camera bracket is a machined part, and avoid using aluminum profiles for the bracket material;

Second, shake the bracket and observe whether there is obvious wobbling. If wobbling occurs, readjust and secure the bracket;

Third, shake the Camera and observe whether there is obvious wobbling to ensure that the Camera is securely installed.

• Ensure that the Calibration Board is stably placed within the Camera field of view

For the Eye to hand Camera installation method, the Calibration Board must be mounted on the Tool to ensure that it is within the Camera field of view.

• Ensure that Robot accuracy meets the project requirements

If Robot accuracy does not meet the project requirements, please refer to Calibration Verification to correct Robot accuracy.

1.4 Collect Samples

1.4.1 Collect the Calibration Board and Robot Coordinates

(1) Adjust the position of the Calibration Board, place it in the target object placement area, and click Start Sampling.

(2) Click Add Sample. If the sample is valid, a Saved Successfully message appears; if the sample is close to an existing sample, the sample is invalid and a save failure message appears.

(3) Check the detection results. If all detection items are green icons, coordinate axes and feature points appear in the visualization window, and all circle centers are green, the current pose meets the requirements.

The detection is divided into 4 aspects:

1.4.2 Touch the Calibration Board with the Needle Tip

(1) Click Start Sampling, control the Robot to move, and touch the centers of the corresponding concentric circles with the needle tip in the numerical order marked in the visualization window.

(2) Click Add Sample to collect the Robot coordinates during touch-point sampling.

(3) Repeat the above steps to collect at least 3~6 concentric-circle touch-point samples.

• Click Next

1.4.3 [Optional] Add a Calibration Position

During the calibration sampling stage, the system uses single-pose calibration mode by default. However, in specific application scenarios, it can be extended to a multi-position calibration strategy to improve calibration robustness and system adaptability under complex working conditions:

• To address accuracy deviations caused by depth-of-field changes in wide-angle vision systems, layered sampling along the Z-axis can effectively balance the error distribution across different focal planes;

• In work environments with limited space, when more than 3 feature points cannot be collected from a single Calibration Board placement, multiple Calibration Board placements and staged sampling can be used to accumulate the minimum required sample size.

Click Add Position to add a new calibration position, then repeat 1.4.1 Collect the Calibration Board and Robot Coordinates and 1.4.2 Touch the Calibration Board with the Needle Tip to collect calibration samples and perform Calibration Board touchpoint sampling.

1.4.4 Calculate Calibration Results

Click Calculate Results. PickWiz calculates the calibration results based on the collected samples. If the calibration error does not meet the requirements, perform Calibration Result Inspection and Analysis.

1.5 Select the eye-hand calibration configuration

After the Calibration Workflow is complete, return to the Run Configuration interface, click Job Information, open the Eye-Hand Calibration drop-down list, and select the corresponding eye-hand calibration configuration.

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