Redundant Sensor Tile Protection for Mobile Robots and AGVs
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Solution Overview
Problem
Current safety systems for human-robot collaboration and personal protection in logistics areas, particularly with heavy-duty AGVs and industrial trucks, fail to meet the required Safety Integrity Level (SIL) and Performance Level (PL) standards, as they lack redundancy and self-monitoring capabilities, and are not suitable for all-round protection.
Innovation Solution
A redundant safety sensor system using a combination of optical proximity sensors and tactile sensors, designed to put the device into a safety-limited-speed state or safe operating stop, with continuous self-monitoring and diverse detection capabilities, ensuring SIL 2 and PL d are met, and providing comprehensive protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety sensor system is designed with redundancy and self-monitoring capabilities to meet SIL 2 and PL d standards, then the safety integrity level and performance level are improved, but the device complexity and cost increase
Solution Approach 1:
The safety sensor system is divided into multiple independent channels (at least two channels as required by SIL 2/PL d standards). Each channel processes sensor signals independently and can detect safety-relevant situations autonomously. This segmentation provides redundancy while maintaining manageable complexity through modular architecture.
Solution Approach 2:
The evaluation unit continuously monitors the functional parameters of the sensor system itself (self-monitoring). The system detects its own operational status, signal plausibility, and potential failures automatically without external intervention. This self-service capability ensures continuous safety verification while integrating monitoring functions into the existing system structure.
2Measurement precision
If optical proximity sensors and tactile sensors are combined in a redundant safety sensor system, then the detection capability and safety response are improved, but the device complexity increases
Solution Approach 1:
The system combines optical proximity sensors (for early detection of approaching objects) and tactile sensors (for direct contact detection) into a unified safety sensor system. Both sensor types feed into a common evaluation unit that processes signals from both channels, enabling comprehensive detection coverage while integrating multiple sensor modalities into a single coordinated system.
Solution Approach 2:
The evaluation unit serves multiple functions: it evaluates signals from both optical and tactile sensors, monitors functional parameters of the entire sensor system, determines safety-relevant situations, and triggers appropriate safety responses. This multi-functionality reduces overall system complexity by consolidating control logic into a single versatile component.
3Reliability
If continuous self-monitoring of functional parameters is implemented, then the reliability and safety integrity are improved, but the use of energy and system complexity increase
Solution Approach 1:
The evaluation unit continuously monitors functional parameters of the sensor system without interruption to ensure constant safety verification. This continuous monitoring is integrated into the normal operation cycle, utilizing the same processing resources during regular system operation rather than adding separate dedicated monitoring cycles, thereby minimizing additional energy consumption.
Solution Approach 2:
The self-monitoring function provides continuous feedback about the operational status of sensor components and signal plausibility. This feedback mechanism uses the existing evaluation unit to assess system health in real-time, leveraging the same computational resources already allocated for safety evaluation, thus avoiding the need for separate high-energy monitoring subsystems.
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
The system ensures high operational safety for human-machine collaboration, particularly in industrial robots and AGVs, by effectively detecting and responding to objects and people, preventing collisions and ensuring safe operation even at high speeds.
Implementation Method 1
optical distance sensor (23, 35) for detecting a distance (20, 21) to an object or person
Implementation Method 2
reflection sensor or structured light sensor
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a device for protecting a mobile appliance under machine or automatic control, more particularly a handling device such as a robot (5) or an AGV (60). The device is provided with a safety sensor system for detecting objects in a workspace of, at a distance from, or in surroundings of, the appliance, and also with a safety control system which interacts with an appliance control system of the appliance and thus controls safety-relevant appliance functions as a function of signals from the safety sensor system. The safety sensor system includes a tactile sensor system having at least one first sensor (22, 41, 30, 31, 32, 33) and a proximity sensor system having at least one second sensor (23, 48, 35, 36). The first sensor (22, 41, 30, 31, 32, 33) and the second sensor (23, 48, 35, 36) are each based on an optical measuring principle and/or the safety sensor system is redundantly designed. Furthermore, a tile (62) is proposed for attachment to a surface or for integration into a surface of the mobile appliance under machine or automatic control, as is a method for protecting the appliance.