Weld seam tracking technology for welding robots

As a key research direction in industrial automation, the core value of weld seam tracking technology lies in real-time perception of the spatial position of the weld seam and dynamic correction of the robot's motion trajectory to achieve precision welding. This technology effectively solves the problem of welding quality fluctuations caused by workpiece assembly errors, thermal deformation, etc. in traditional teaching programming, and becomes an important support for the intelligent manufacturing system.

The system consists of a closed-loop control system consisting of a sensor unit, a control unit, and an execution unit:

1. Sensor unit

Laser vision sensor: emits laser stripes and collects deformation images, and analyzes the three-dimensional coordinates of the weld seam based on triangulation (accuracy of ±0.05mm)

Arc sensing: inverts the weld seam position through welding current/voltage fluctuations, suitable for strong interference scenarios such as submerged arc welding

Ultrasonic sensing: monitors deep penetration status and specializes in thick plate welding quality control

2. Control unit

Integrates PID algorithm and intelligent control strategy (such as fuzzy control, neural network), processes sensor data in real time, and generates correction instructions. Taking a certain automobile welding line as an example, the adaptive PID algorithm compresses the response time to 10ms.

3. Execution unit

The six-axis welding robot accurately executes trajectory correction instructions. Some high-end models integrate force control modules to achieve contact-type adaptive deviation correction. Multi-sensor fusion resists smoke and splash interference; intelligent algorithms predict thermal deformation trajectory deviation; six-axis linkage achieves 0.1mm level real-time deviation correction.

This technology increases the tolerance of workpiece assembly from ±0.5mm to ±2mm, greatly reducing the rework rate. In the welding of engineering machinery booms, the system successfully overcomes the 3.5mm thermal deformation deviation, and the weld pass rate is increased to 99.3%.