Electro-hydraulic Steering Control System with Dual-Input Validation
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Solution Overview
Problem
Existing steering control systems for work vehicles, such as tractors, are prone to undesirable steering actions due to electro-hydraulic or electrical failures, which can occur before the system can initiate a corrective response, leading to unintended vehicle movements.
Innovation Solution
An electronically controlled electro-hydraulic steering system that requires both electro-hydraulic and driver-initiated actions to steer the vehicle, incorporating a pilot system with piloted control valves and pressure control valves to ensure safe and controlled steering, even in the event of system failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electro-hydraulic valve is used to control steering, then steering responsiveness is improved, but the risk of unwanted steering action due to system failure increases
Solution Approach 1:
The system performs preliminary validation by requiring dual independent inputs (electronic command and driver steering input) before actuation. The controller continuously monitors both the electronic steering command and the actual steering wheel position, and only activates the electro-hydraulic valve when both inputs corroborate the intended steering action, preventing unwanted actuation from single-point failures
Solution Approach 2:
The system implements feedback by continuously monitoring the steering wheel position sensor and comparing it with the electronic steering command. This closed-loop feedback allows the controller to detect discrepancies between intended and actual steering inputs, identifying potential failures and preventing unwanted steering actions by requiring corroboration from multiple independent sources
2Reliability
If a corrective signal is generated after detecting undesirable steering action, then system safety is improved, but the response time is too long to prevent unintended steering
Solution Approach 1:
The system performs preliminary validation by requiring dual independent inputs (electronic command and driver steering input) before actuation. The controller continuously monitors both the electronic steering command and the actual steering wheel position, and only activates the electro-hydraulic valve when both inputs corroborate the intended steering action, preventing unwanted actuation from single-point failures
Solution Approach 2:
The system applies preliminary anti-action by implementing a fail-safe mechanism that prevents unwanted steering action before it can cause harm. The dual-input validation system actively counteracts potential failures by requiring corroboration from multiple independent sources, and the正常情况下 the system maintains a ready-to-activate corrective state that can immediately counteract any detected anomalies
3Productivity
If steering control is fully automated with electro-hydraulic valves, then productivity is improved, but the system becomes vulnerable to electrical and electro-hydraulic failures
Solution Approach 1:
The system applies local quality by implementing redundancy specifically at the critical decision-making point (the controller's input validation logic) rather than duplicating the entire steering system. The electronic steering command and steering wheel position sensor provide localized backup validation at the control signal level, maintaining high productivity while adding targeted failure resistance where it is most needed
Solution Approach 2:
The system implements feedback by continuously monitoring the steering wheel position sensor and comparing it with the electronic steering command. This closed-loop feedback allows the controller to detect discrepancies between intended and actual steering inputs, identifying potential failures and preventing unwanted steering actions by requiring corroboration from multiple independent sources
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
Prevents undesirable steering actions by ensuring that steering actions are only initiated with both driver input and system validation, reducing the likelihood of unintended vehicle movements and enhancing safety.
Implementation Method 1
A pilot system includes a pilot line operatively connected to the steering input device. A piloted system includes a direction control valve, operatively connected to the pilot line
Implementation Method 2
A first pressure control valve operatively connected to the first pilot line and having a first pressure control valve output, a second pressure control valve operatively connected to the second pilot line and having a second pressure control valve output
Data Source
AI summary
A steering system for a work vehicle having a steerable wheel. The steering system includes a steering input device configured to provide a first steering input and a second steering input to move the steerable wheel. A pilot system is operatively connected to the steering input device and includes a first pilot line operatively connected to the first steering input and a second pilot line operatively connected to the second steering input. A piloted system is operatively connected to the pilot system and includes a direction control valve operatively connected to each of the first and second pilot lines and to a steering cylinder. The steering cylinder is coupled to the steerable wheel. The direction control valve responds to each of the pressure signals of the first and second pilot lines to adjust the position of the steering cylinder which in turn moves the steerable wheel.