Working Machine Lever Neutral Detection With Dual Tilt Sensors
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Solution Overview
Problem
Existing control devices for work equipment may operate inappropriately due to abnormalities in the detection of tilt angles from the neutral position of operation levers, leading to potential safety issues.
Innovation Solution
A control device that utilizes two detection sensors for the operation lever, repeatedly checks for signals corresponding to the neutral position at startup, outputs alarms for abnormal conditions, and controls the work equipment based on valid signals before a predetermined time elapses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the control device operates work equipment at faster speed as the tilt angle from neutral position is larger, then productivity is improved, but reliability deteriorates when abnormality occurs in detection signals
Solution Approach 1:
The control device performs preliminary verification of detection signals at startup before normal operation begins. By checking whether both detection signals indicate the neutral position at startup, the system proactively identifies potential sensor abnormalities before they can cause inappropriate high-speed operation, thus preventing reliability issues while maintaining productivity during normal operation
Solution Approach 2:
The control device continuously monitors detection signals from both tilt amount sensors and uses feedback from the startup verification to determine operational parameters. When abnormality is detected through signal inconsistency, the system provides feedback to limit operation speed, ensuring reliable control while maintaining fast operation under normal conditions
2Measurement precision
If the control device uses two detection units with opposite characteristics, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The control device merges the outputs from two detection units with opposite characteristics into a unified control system. By combining both sensors and their signals, the system achieves higher measurement precision through cross-verification while managing complexity through integrated signal processing that compares both readings to determine appropriate operation parameters
3Reliability
If the control device outputs alarm and stops operation when abnormality is detected, then reliability is improved, but productivity decreases due to operation interruption
Solution Approach 1:
The control device applies local quality control by differentiating between complete shutdown and limited operation based on the specific abnormality detected. Instead of uniformly stopping all operations, the system selectively limits only the work equipment operations that could be unsafe, while allowing other non-critical functions to continue, thus maintaining partial productivity while ensuring safety
Data Source
AI summary
The control device includes an acquisition unit configured to repeatedly acquire a first detection signal output according to a tilt amount of an operation lever by a first tilt amount sensor configured to detect the tilt amount of the operation lever of the work equipment tilted from a neutral position in a first direction or a second direction opposite to the first direction, and a second detection signal output according to the tilt amount by a second tilt amount sensor configured to detect the tilt amount, and a control unit configured to repeatedly determine whether or not the first detection signal and the second detection signal are a value corresponding to the neutral position at a time of start of the work machine, and output an alarm indicating that both of the first detection signal and the second detection signal are not the value corresponding to the neutral position.