As the robots advance rapidly and are applied in various domains, it is essential to ensure that the robots have high performance, quality, and reliability.
The robots need to undergo a calibration process to ensure their accuracy and performance before being delivered to the customers.
Robots also require periodic calibration to maintain their accuracy, as they may deviate from their intended paths over time. Calibration ensures that the robots perform reliably and consistently for intricate tasks.
Robot calibration is the process of improving the accuracy of robots, which includes joint angle calibration, kinematic calibration and non-kinematic calibration.
Joint Angle Calibration: Compensate the position and orientation of the robot’s joints to match the desired motion. It improves the accuracy and repeatability of the robot’s movements.
Kinematic Calibration: Kinematic calibration concerns the entire geometric robot calibration which includes angle offsets and joint lengths.
Non-kinematic Calibration: It models errors besides geometric defaults such as stiffness, joint compliance, and friction.
Scantech’s M-Track intelligent robotic path planning and guiding system can be used to obtain the robots’ positions accurately and verify their poses quickly. It enables engineers to calculate key D-H parameters such as coupling ratio, reduction ratio, zero location of each axis, and rod length.
Let’s find out how Scantech 3D system M-Track can be used to ensure the precision of cobots.
Calibrating Desktop Cobots
UFACTORY, a pioneer in developing desktop open-source cobots, uses Scantech’s M-Track system to calibrate cobots with high precision and efficiency.
The company has deep expertise and years of experience in various aspects of cobot design, such as underlying algorithms, servo systems, control systems, joint mechanisms, and appearance aesthetics. Its cobots are widely used in areas such as education and research, unmanned retail, automated inspection and more.
Before delivering the products to the customers, accuracy calibration is a crucial step for UFACTORY. Traditional methods can only adjust the accuracy of the cobot’s poses in one dimension, which is not only inefficient but also prone to errors and variations, affecting the product quality and consistency.
By using Scantech’s M-Track system, the calibration process becomes more precise and efficient, reducing the delivery time and enhancing the accuracy and reliability of the cobot.
Customer Requirements
The customer wants to measure the tool center point (TCP) under different poses and locations and use the deviation value from the theoretical value to adjust and correct the robot’s parameters within the system, thereby improving the cobot’s position accuracy.
Conventional Method
Line drawing method: This method can only compensate for one dimension, and has low accuracy (up to 3-5mm) and poor stability.
Commonly used laser trackers: This method is very expensive.
Solution and Workflow
M-Track Intelligent Path Planning and Guiding System
M-Track is composed of three components: a 3D tracking system i-Tracker, a tool simulator, and path planning software. The customer used i-Tracker and the software to acquire the 6D poses of the cobot’s tool center point (TCP).
This solution overcomes the challenges of high labor costs, inefficient human-machine interaction, and low productivity, and significantly improves product quality.
Create a model from background reference points: Use i-Tracker to detect the background points and establish the correct geodetic coordinate system.
Create a model of object: Use the M-Track software to input the end effector model and create the model of object.
Track the object and output the coordinates: Use the API to automatically track the object and output its actual coordinate value.
Compensate and correct the cobot’s motion parameters: Use the compensation software to input the actual and theoretical coordinate points and obtain the compensation value, which is used to correct the cobot’s motion parameters.
Advantages of Using M-Track for Calibrating Cobots
The tracking system uses stereoscopic vision technology to track the cobot’s path accurately and efficiently. It can get the 6D pose of the tool center point with high precision.
M-Track ensures that the cobots are calibrated and operated safely with its high-precision tracking. The tracking accuracy is 0.064 mm for a 10.4 m³ range and 0.078 mm for an 18 m³ range.
M-Track is a system that can improve product accuracy by reducing the errors caused by the cobots’ poses and motions. It captures the cobots’ poses and compare them with the desired poses.
This allows engineers to verify and adjust the cobots’ parameters and correct their deviations quickly and easily. As a result, the cobots can perform more precise and consistent tasks.
It can increase the profitability by saving time and resources. By using i-Tracker, engineers can calibrate the cobots faster and easier than using traditional methods.
This can reduce the labor and material costs of the calibration process, as well as the downtime and maintenance costs of the cobots. Therefore, the manufacturing of cobots can be more efficient and productively, and generate more revenue for the company.
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