Grappler Overload Protection via Arm Spread Estimation
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Solution Overview
Problem
Existing safety systems for devices like aerial equipment fail to effectively prevent overload conditions that can lead to equipment damage or personnel harm, as they lack real-time load monitoring and alert mechanisms to prevent unsafe load-bearing situations.
Innovation Solution
A grappler overload protection system that includes sensors to measure the spread of grappler arms and estimate the load weight, with a controller determining if the load exceeds safety limits, preventing further operation and alerting users of potential overloads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing safety systems are used for aerial equipment, then basic safety functions are provided, but real-time load monitoring and overload prevention capabilities are lacking
Solution Approach 1:
The system performs preliminary load assessment by measuring grappler arm spread before the aerial device attempts to lift or bear the load. The controller estimates the load weight based on the measured spread and compares it against predetermined safety limits, preventing overload conditions before they occur rather than reacting after overload has occurred.
Solution Approach 2:
The system continuously monitors grappler arm spread using sensors and feeds this information back to the controller, which estimates load weight and compares it to safety limits. This closed-loop feedback mechanism enables real-time load monitoring and dynamic adjustment of device operation to maintain safety while preventing information loss about actual load conditions.
2Reliability
If load monitoring and prevention mechanisms are added, then equipment damage and personnel harm are prevented, but device complexity increases
Solution Approach 1:
The system uses grappler arm spread as an intermediary measurement that indirectly indicates load weight without requiring direct weight sensors on the aerial device. By measuring the geometric configuration of the grappler arms and using this as a proxy for load estimation, the system achieves load monitoring with simpler, more integrated components rather than adding complex direct weight measurement systems.
Solution Approach 2:
The grappler arm spread measurement serves multiple functions: it characterizes the grappler configuration for its primary gripping function, and simultaneously provides the basis for load weight estimation for safety monitoring. This multi-functionality allows the system to gain overload protection capabilities using existing structural elements and measurements rather than adding dedicated, separate monitoring hardware.
3Reliability
If real-time load assessment is implemented, then unsafe operating conditions are avoided, but measurement and control requirements increase
Solution Approach 1:
The system employs grappler arm spread as an intermediary parameter that is easily measurable using standard position sensors already present on the aerial device. Instead of directly measuring difficult-to-obtain load weight, the system measures the accessible and easily monitored grappler arm configuration, which serves as a reliable proxy for load assessment.
Solution Approach 2:
The system replaces complex mechanical weight measurement systems with electronic sensing of grappler arm positions combined with computational estimation. By using sensors to measure arm spread angles and positions, and then calculating load weight through control algorithms, the system achieves accurate load monitoring without the mechanical complexity of direct weight measurement apparatus.
Data Source
AI summary
A grappler overload protection system uses a load-measuring device to provide a first load indication for preventing the grappler from bearing an unsafe load when the first load indication exceeds a first limit. A grappler overload protection method determines a spread of grappler arms based on information from a first sensor, determines an expected weight of the load based on the spread of the grappler arms, and compares the expected weight to a first limit for preventing the grappler from bearing an unsafe load. The method may optionally determine an angle of a boom supporting the grappler for determining an expected torque on the boom based on the boom angle and the expected weight of the load. The method may take preventative measures to prevent the grappler from bearing the load when the expected weight exceeds the first limit or when the expected torque exceeds a second limit.