Joystick Return-to-Center Control for Speed-Adaptive Hydraulic Steering
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Solution Overview
Problem
Existing hydraulic steering systems lack the ability to dynamically adjust the restoring force on the joystick handle based on vehicle parameters, such as speed, to enhance safety and prevent rapid steering movements that could lead to dangerous situations.
Innovation Solution
A hydraulic steering system with a controller and motor, such as a stepper motor, that adjusts the restoring force on the joystick handle based on vehicle parameters, including speed, to ensure safe and precise steering, and includes a mode for automatic steering control via GPS when the handle is not being held.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant restoring force is used on the joystick handle, then the operator can easily control the steering at low speeds, but rapid steering movements cannot be prevented at high speeds
Solution Approach 1:
The restoring force is made dynamic rather than constant. The return-to-center means adjusts the restoring force in real-time based on vehicle speed parameters. At higher speeds, the restoring force increases to prevent rapid steering movements, while at lower speeds, the force decreases to maintain ease of operation. This dynamic adjustment resolves the contradiction between ease of operation and safety.
Solution Approach 2:
The system changes the parameter of restoring force magnitude based on vehicle speed. The controller modifies the restoring force parameter dynamically according to detected vehicle speed, increasing it when speed is high and decreasing it when speed is low. This parameter change allows the system to adapt to different operating conditions and resolve the contradiction between ease of steering and prevention of rapid movements.
2Reliability
If the restoring force is increased to prevent rapid steering movements, then safety is improved, but the operator must exert more force to steer
Solution Approach 1:
The system dynamically adjusts the restoring force based on real-time vehicle speed detection. When the vehicle is moving fast, the restoring force increases to prevent dangerous rapid steering movements. When the vehicle is moving slowly or is stationary, the restoring force decreases, making it easier for the operator to steer. This dynamic behavior allows the system to provide high safety when needed while maintaining ease of operation when rapid steering is not a risk.
3Extent of automation
If return-to-center means are used to move the handle to neutral position, then the vehicle can be automatically centered, but the handle cannot indicate steering direction when GPS control is active
Solution Approach 1:
The joystick handle serves multiple functions depending on the operational mode. When GPS automatic steering is active, the handle remains in the neutral position indicated by the return-to-center means, providing automated control. When the operator takes manual control, the handle visually indicates the steering direction through its position. The system switches between these functions based on mode detection, allowing both automation and manual indication capabilities to coexist.
Solution Approach 2:
The system uses feedback from mode detection (via switch or sensor) to determine how the handle should behave. When automatic GPS steering mode is detected, the system feedbacks by maintaining the handle in the neutral position through the return-to-center means. When manual control mode is detected, the system feedbacks by allowing the handle to indicate steering direction. This feedback mechanism resolves the contradiction by adapting the handle's function based on the current operational context.
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
The system provides enhanced safety by varying the restoring force on the joystick handle according to vehicle speed, preventing rapid steering movements and ensuring precise control, while allowing for automatic steering when the handle is not in use.
Implementation Method 1
return to center means (7) comprising a controller (9) and a motor (10) acting on the handle (5) of the joystick (3)... the motor (10) produces a restoring force on the handle (5)
Implementation Method 2
hydraulic steering system (1) comprises a steering motor (2) and a joystick (3)... Means for supplying hydraulic fluid to the steering motor (2) are not shown separately
Data Source
AI summary
A hydraulic steering system (1) is described. The hydraulic steering system (1) comprises a steering motor (2) and a joystick (3) having a housing (4), a handle (5) mounted movably to the housing (4), a handle angle sensor (6) and return to center means (7) producing a restoring force on the handle (5). Such a system should help an operator to steer a vehicle in a safe manner. To this and the return to center means (7) comprises an input (8) for a parameter of a vehicle to be steered and produces a variable restoring force depending on a signal at the input and/or of an angle of the handle (5).