Arc Welding Robot Timing Control for Predictable Arc Start
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Solution Overview
Problem
Existing arc welding robot systems face challenges in predicting and optimizing the precedence time for issuing welding start instructions due to uncertain elements such as variations in the distance between the weld tip and the workpiece, wire burn-back amounts, and wire feed speeds.
Innovation Solution
An arc welding robot system with a robot controller that includes a measuring unit to determine the time from sending a welding start instruction to arc generation, a storage unit to store measurement values, and a precedence time determination unit to calculate the optimal precedence time for issuing welding start instructions based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed precedence time is used for issuing welding start instructions, then the control system is simple, but the takt time cannot be optimized due to uncertain elements in waste time
Solution Approach 1:
The system performs preliminary measurements of waste time at each welding position before actual welding operations. The measuring unit records the time from when the welding start instruction is sent to when the arc is actually generated, and these measurements are stored in advance for later use in calculating optimized precedence times.
Solution Approach 2:
The system implements a feedback mechanism where measured waste time data from previous welding operations is used to adjust and optimize the precedence time for subsequent operations. The precedence time determination unit continuously refines the timing based on accumulated measurement data, creating a closed-loop control system that improves productivity while maintaining manageable complexity.
2Productivity
If the welding start instruction is issued earlier to reduce waste time, then productivity improves, but welding quality may deteriorate due to unpredictable arc generation timing
Solution Approach 1:
The system performs preliminary measurements of waste time at each welding position before actual welding operations. The measuring unit records the time from when the welding start instruction is sent to when the arc is actually generated, and these measurements are stored in advance for later use in calculating optimized precedence times.
Solution Approach 2:
The system dynamically adjusts the precedence time parameter based on measured waste time data. By changing the timing parameter according to actual measurements rather than using a fixed value, the system optimizes welding speed while ensuring reliable arc generation and maintaining welding quality.
3Measurement precision
If multiple measurements are taken to determine accurate precedence time, then welding precision improves, but the setup time and system complexity increase
Solution Approach 1:
The robot controller is designed to perform multiple functions: it controls the welding robot, sends welding start instructions, measures waste time, stores measurement data, and calculates optimized precedence times. By making the controller multi-functional, the system achieves high measurement precision without adding separate dedicated measurement devices, thus avoiding increased system complexity.
Solution Approach 2:
The system performs self-measurement of waste time using its own controller and existing hardware resources. The measuring unit utilizes the robot controller's internal timing capabilities to measure the waste time, eliminating the need for external measurement equipment and reducing overall system complexity while maintaining high measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for the optimization of the precedence time for issuing welding start instructions, thereby reducing takt time and improving welding efficiency even in situations where predicting waste time is difficult.
Implementation Method 1
an arc welding robot system, which performs arc welding by operating an arc welding robot equipped with a welding torch
Data Source
AI summary
An arc welding robot system includes: a robot on which a welding torch is mounted; a robot control device; and a welding power supply that supplies power to the welding torch. The robot control device includes: a welding command unit that outputs a command to the welding power supply; a measuring unit that measures, a plurality of times for each welding location, an amount of time from when the welding command unit sends a welding start-up command to the welding power supply in accordance with a welding start command of an arc welding program until a notification signal indicating generation of an arc is returned from the welding power supply; a storage unit that stores a plurality of measured measurement values for each welding location; and a preceding time determination unit that determines, for each welding location, a preceding time for outputting the welding start-up command in advance of a timing at which the welding torch arrives at a welding start point corresponding to the welding start-up command, the determination being made on the basis of the values of the plurality of times of measurements for each welding location stored in the storage unit.