In the field of industrial automation, the repeatability accuracy of industrial robots is one of the key indicators for measuring their performance. This parameter is crucial as it directly affects the accuracy and efficiency of the robot's task execution. Repetitive positioning accuracy refers to the precision that a robot's end effector (such as a fixture or welding gun) can achieve at the same position while repeatedly performing the same task. Usually, this parameter is measured in millimeters or micrometers.
To better understand the accuracy of repeated localization, let's take a simplified example. Assuming that the robot needs to move an object from point A to point B, the required movement distance is 100 millimeters. The first time the robot moved, it may have slightly exceeded target point B by 100.02 millimeters. During the second movement, it may have been slightly shorter, moving 99.8 millimeters. So the repeated positioning accuracy of the robot is 0.04 millimeters (100.02-99.8=0.04mm).
Factors affecting the accuracy of repeated positioning
1. Joint drive accuracy and stability: The joints of a robot are usually composed of servo motors and reducers, and the accuracy and stability of these components are key to ensuring that the robot can accurately control its position.
2. Sensor resolution: Robots rely on sensors, such as encoders, to detect the position of their joints. The higher the resolution of the sensor, the more accurate its measured position accuracy.
3. Structural rigidity: If the arm and joints of the robot have high rigidity, they can minimize deformation during movement, which is beneficial for improving the accuracy of repetitive positioning.
4. Environmental factors: Changes in the environment, such as temperature, humidity, and vibration, may affect the positioning accuracy of robots.
Application case: Automotive welding assembly line
In the automotive manufacturing industry, industrial robots on the welding line need to accurately weld the exterior panels of the car body to the frame. This type of application typically requires a repeat positioning accuracy within ± 0.1 millimeters to ensure the quality and aesthetics of the weld seam. For example, the repeated positioning accuracy of a welding robot is ± 0.05 millimeters, which means that the position repeatability of its end effector can be controlled within ± 50 micrometers, which is completely sufficient for precise welding of large workpieces.
In contrast, if the repetitive positioning accuracy of a robot is only ± 0.3 millimeters, it may cause significant positional deviation during the welding process, thereby affecting the welding quality. This type of robot is more suitable for assembly or handling tasks with lower precision requirements.
Repetitive positioning accuracy is not only an important parameter for measuring the performance of industrial robots, but also determines which specific automation production scenarios robots can be applied to. High precision repetitive positioning enables robots to perform process tasks that require high repeatability, such as precision assembly, high-quality welding, etc., thus playing a key role in automated production. Therefore, when designing and selecting industrial robots, the accuracy of repeated positioning is an important consideration that cannot be ignored.