Hydraulic Steering Control for Automated Mode Transition
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Solution Overview
Problem
Existing steering systems for vehicles with caster-mounted rear wheels face complexity in transitioning between manual and automated steering modes due to mechanical links, which impede efficient control and automation of front and rear wheel steering.
Innovation Solution
A hydraulic steering system that eliminates mechanical links between the steering input device and steering control devices, using valve assemblies and hydraulic circuits to control wheel speed and direction, allowing for seamless transition between manual and automated steering modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If mechanical links (rack and pinion, Ackermann linkage) are used to connect steering input device to steering control devices, then steering control can be achieved, but the system complexity increases and transition between manual and automated modes becomes difficult
Solution Approach 1:
The patent removes the mechanical link (rack and pinion or Ackermann linkage) that traditionally connects the steering input device to the steering control devices. By extracting this mechanical connection, the system eliminates the conflict between manual and automated mode operation, allowing the automated steering controller to directly control the steering actuators without mechanical interference from the steering wheel linkage.
Solution Approach 2:
The patent replaces the mechanical linkage system with an electronic control system. The steering input device remains for manual operation, but its mechanical connection to the control devices is removed. Instead, an automated steering controller uses electronic signals to control the steering actuators, substituting the mechanical transmission path with an electronic control architecture that enables seamless mode transitions.
2Ease of operation
If mechanical links are used for steering control, then steering function is achieved, but the ease of operation deteriorates due to interference between manual and automated control
Solution Approach 1:
By removing the mechanical link between the steering input device and the steering control devices, the patent eliminates the physical conflict that occurs when trying to switch between manual and automated modes. The driver can operate the steering wheel normally for manual control, or the automated system can take over without mechanical resistance, significantly improving ease of operation.
Solution Approach 2:
The patent introduces an electronic control system as an intermediary between the driver's steering input and the actual steering actuators. This electronic mediator can interpret the driver's intentions, determine whether automated or manual control should be active, and smoothly transition between modes without the mechanical conflict that would otherwise impede easy operation.
3Measurement precision
If dedicated hydraulic machines are provided for each front wheel to enable independent driving, then steering precision is improved, but the device complexity increases
Solution Approach 1:
The patent combines the control of multiple steering actuators under a single automated steering controller. Instead of having separate control systems for each hydraulic machine, the controller integrates the control logic and coordinates the operation of all steering actuators through a unified electronic control architecture, reducing overall system complexity while maintaining the precision benefits of independent wheel control.
Solution Approach 2:
The automated steering controller serves multiple functions: it controls all steering actuators, manages mode transitions between manual and automated operation, monitors system status, and coordinates the operation of dedicated hydraulic machines. This multi-functional controller reduces the need for separate control systems for each component, simplifying the overall hydraulic and control system architecture.
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
Enables efficient and precise control of both front and rear wheels, improving steering accuracy and ease of operation by allowing for automated steering without mechanical interference, enhancing vehicle stability and maneuverability.
Implementation Method 1
An operational pressure at the valve assembly may be determined with a pressure sensor
Data Source
AI summary
A steering system and method are described for a vehicle having steerable wheels, with steering of the wheels controlled, at least in part, by a valve assembly. A ground speed of the vehicle may be determined. Whether a steering command is being provided to a valve assembly may also be determined. An operational pressure at the valve assembly may be determined with a pressure sensor. A threshold pressure may be determined based upon the ground speed and/or whether a steering command is currently being provided. The operational pressure may then be compared with the operational pressure, and steering control with the valve assembly disabled based upon the comparison.