Work Vehicle Brake Control via Dual Position Sensors
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Solution Overview
Problem
Malfunctions in position sensors can cause work vehicles to abruptly start traveling or have their brakes released incorrectly, leading to unintended movement due to erroneous position determinations of control levers.
Innovation Solution
A work vehicle configuration that includes travel and stop operation pathways for the steering lever, with dedicated sensors to detect positions and a control unit that ensures the brake is only released when the lever is confirmed to be at a neutral position, preventing erroneous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single position sensor is used to detect control lever position for both brake release and travel control, then the device complexity is reduced, but the reliability decreases due to potential malfunction causing erroneous brake release
Solution Approach 1:
The patent divides the position detection function into two separate sensors: a first position sensor for detecting brake release conditions and a second position sensor for detecting travel control conditions. This segmentation allows independent verification of each function, preventing a single sensor malfunction from causing both brake release and travel control errors, thus resolving the contradiction between device simplicity and operational reliability.
Solution Approach 2:
The control unit acts as an intermediary that receives signals from both position sensors and independently processes them. It requires confirmation from both the first position sensor (for brake release) and the second position sensor (for travel readiness) before allowing vehicle operation. This intermediary processing ensures that no single sensor can falsely trigger both functions simultaneously.
2Ease of operation
If the brake is released based solely on position sensor detection, then the ease of operation is improved, but the safety deteriorates due to potential abrupt vehicle movement
Solution Approach 1:
The system applies preliminary anti-action by requiring dual confirmation before brake release: the first position sensor must detect the control lever in the released position, and the second position sensor must confirm the vehicle is ready for travel. This preliminary verification prevents unintended vehicle movement by ensuring the brake is only released when both conditions are genuinely met, counteracting potential sensor malfunctions before they can cause harm.
Solution Approach 2:
The control unit implements feedback by continuously monitoring both position sensors and using their combined information to control brake release. The system only releases the brake when feedback from both sensors confirms appropriate conditions, creating a safety loop that prevents abrupt or erroneous vehicle movement while maintaining ease of legitimate operation.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A brake control unit (35) configured to control a brake (36) to a braked state in response to a brake position sensor (32) having detected that a steering lever (18) has been operated to a stop position and to a released state in response to the brake position sensor (32) having detected that the steering lever (18) has been operated from the stop position toward a travel operation pathway and a travel position sensor (30) having detected that the steering lever (18) is at a neutral position, at which the steering lever (18) is placeable to stop travel.