Robot Safety Control Circuit With Non-Overlapping Test Pulses
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Solution Overview
Problem
Existing safety control systems for industrial robots rely on simple logic comparison for diagnosing the connection between external safety-input devices, which may not comprehensively detect malfunctions, failing to meet the functional safety standards set by ISO 13849-1 and ISO 10218.
Innovation Solution
A safety control system and method that generates non-overlapping test signals through dual interface circuits and channels, allowing for redundant detection of abnormalities in safety-input device connections, ensuring compliance with ISO 13849-1 and ISO 10218 standards by accurately identifying and addressing any issues in the safety channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple logic comparison is used for diagnosing safety-input device connections, then the device complexity is reduced, but the measurement precision and reliability of malfunction detection deteriorates
Solution Approach 1:
The diagnosis system is segmented into multiple independent test signal channels (first test signal channel and second test signal channel), each with dedicated interface circuits. This segmentation allows comprehensive testing of different signal paths without requiring a monolithic complex system, thereby maintaining detection precision while managing complexity through modular architecture.
Solution Approach 2:
The system performs preliminary testing by transmitting test signals through safety channels before actual safety-critical operations. This preliminary action enables proactive detection of potential malfunctions in signal transmission channels, interface circuits, or safety-input devices, improving detection precision without adding complexity to the operational safety system.
2Device complexity
If a single reference signal is used for diagnosis, then the device complexity is reduced, but the reliability of comprehensive malfunction detection deteriorates
Solution Approach 1:
Different test signals with distinct characteristics are applied to different signal transmission channels and safety-input devices. This local quality approach allows tailored testing for specific channel properties, improving detection reliability by capturing channel-specific anomalies that a single reference signal would miss, while maintaining manageable complexity through targeted rather than universal testing.
3Loss of time
If test pulses of multiple test signals overlap, then the testing process is faster, but the difficulty of detecting and measuring abnormalities increases
Solution Approach 1:
Test signals are transmitted in periodic, non-overlapping pulses through different channels. This periodic action with temporal separation allows clear distinction between signals from different channels, enabling easy detection and measurement of abnormalities without signal interference, while still completing comprehensive testing in reasonable time through efficient sequential pulsing.
Data Source
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AI summary
A safety control system, a safety control circuit, and a safety control method for an industrial robot are provided. The safety control circuit includes: a control circuit, configured to generate a first test signal and a second test signal, wherein a test pulse of the first test signal does not overlap with a test pulse of the second test signal; a first interface circuit and a second interface circuit, connected to the control circuit. The first interface circuit and the second interface circuit respectively transmit the first test signal to the first signal transmission channel and transmit the second test signal to the second signal transmission channel; transmit a first feedback signal fed back from the first signal transmission channel to the control circuit and transmit a second feedback signal fed back from the second signal transmission channel to the control circuit. The control circuit determines, based on the first feedback signal and the second feedback signal, whether the first interface circuit and the first signal transmission channel are abnormal, and whether the second interface circuit and the second signal transmission channel are abnormal; and control the industrial robot to execute a safety strategy in response to abnormality occurring. In this way, safety control of the industrial robot is achieved.