With the development of the manufacturing industry, robot welding technology has become a crucial tool for many manufacturing companies. One of the key elements in robot welding technology is seam tracking, which enables real-time detection of the position and shape of the weld seam during welding and then makes real-time adjustments based on the detection results to ensure welding accuracy and stability.
The seam tracking system primarily consists of three components: sensors, control systems, and actuators. Sensors are the most critical part of this system. Using a laser seam tracking system, it can guide the welding robot to locate the welding gap and complete the welding work. It can detect seams as fine as 0.1mm with a horizontal error of less than 0.04mm and a height error of less than 0.018mm, making it suitable for precision welding. Using a laser seam tracking sensor in conjunction with a welding robot is akin to giving the robot “eyes” that can accurately guide it in welding positioning.
To achieve welding automation and intelligence, the primary challenge is to automate seam detection and real-time tracking and positioning. Robot seam tracking with real-time compensation involves several steps:
- Seam Detection: The first step in robot seam tracking is seam detection, which typically requires the use of sensors. Sensors can monitor the real-time position and shape of the weld seam and transmit this information to the robot control system.
- Coordinate Transformation: Since the coordinate system of the robot and the weld seam often do not match, coordinate transformation is required during robot seam tracking. Specifically, the weld seam information detected by the sensor needs to be transformed into coordinates in the robot’s tool coordinate system. This involves geometric transformations such as rotation and translation. Mathematical models are commonly used for coordinate transformation in practical applications.
- Deviation Calculation: Through coordinate transformation, detected seam information is converted into coordinates in the robot’s tool coordinate system. The next step is to calculate the deviation between the robot and the weld seam. This is usually achieved by calculating the Euclidean distance between the robot’s current position and the seam’s position. If the distance between the robot and the seam exceeds the allowable error range, real-time compensation is required.
- Real-Time Compensation: Once the deviation is calculated, real-time compensation can be performed. The goal of real-time compensation is to reduce the deviation by controlling the robot’s motion trajectory. This includes determining the compensation direction (left, right, up, or down) and calculating the compensation distance based on the magnitude of the deviation. The compensation distance and direction need to be translated into commands that the robot control system can understand to perform real-time compensation operations.
- Welding Control: Execute the welding task according to the planned welding path. By implementing real-time compensation, the robot can more accurately locate the weld seam and perform precise welding. During the welding process, the distance between the robot and the weld seam may continuously change, so feedback control is necessary. By continuously detecting deviations during welding and applying real-time compensation, the robot can more precisely control the welding path, ensuring welding quality and compliance.
Robot seam tracking with real-time compensation is a complex process that involves multiple steps. As the manufacturing industry advances, there are increasing demands for seam tracking systems to ensure high precision, reliability, stability, strong interference resistance, adaptability to different environments, and continuous operation for extended periods of time.
