Hydraulic Steering Priority Control via Activation Sensor
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Solution Overview
Problem
In hydraulic steering systems with feedback properties, the steering initiator, typically a steering handwheel, moves undesirably when the vehicle is steered via an auxiliary-force activated steering valve, preventing driver intervention and potentially leading to dangerous situations.
Innovation Solution
Integration of an activation sensor that deactivates the feedback suppressing device when the steering initiator is activated, ensuring the steering handwheel has priority over the steering valve by using a torque or rotation angle sensor to determine steering intent and an electrically activated brake to prevent feedback from the steering motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the feedback suppressing device is activated to prevent steering handwheel movement during automatic steering, then the stability of the steering system is improved, but the driver's ability to intervene in steering is lost
Solution Approach 1:
The brake's clamping force on the steering shaft is made dynamically adjustable. During automatic steering, the brake is activated to prevent handwheel movement. When the driver activates the steering unit, the brake force is reduced or released, allowing the driver to override the automatic steering. This dynamic adjustment of brake force resolves the contradiction by adapting the restraint level to the current operating mode.
Solution Approach 2:
The system incorporates feedback through the activation sensor that continuously monitors the steering unit's activation state. When the sensor detects that the driver is activating the steering unit (by turning the handwheel), it sends a signal to deactivate the brake. This feedback mechanism ensures that the brake only suppresses handwheel movement when the driver is not attempting to steer, thus maintaining both stability during automatic steering and driver intervention capability when needed.
2Ease of operation
If the steering handwheel is allowed to move during automatic steering, then the driver can intervene when necessary, but the steering handwheel moves undesirably causing disturbance
Solution Approach 1:
The brake acts as an intermediary element between the steering shaft and the steering handwheel. It provides a controlled restraining force that prevents unwanted handwheel movement during automatic steering while still allowing the driver to overcome this resistance when intentionally steering. The brake mediates between the automatic steering system's need for stability and the driver's need for intervention capability.
Solution Approach 2:
The brake applies a preliminary restraining force to the steering shaft before the driver can turn the handwheel during automatic steering. This preliminary anti-action prevents the harmful effect of unwanted handwheel movement. When the driver activates the steering unit, the brake force is reduced, allowing the driver's steering input to overcome the restraint. This preliminary restraint eliminates disturbance while preserving intervention capability.
3Stability of the object's composition
If the brake force is increased to completely prevent steering shaft movement, then the feedback suppression is improved, but the driver cannot activate the steering unit when needed
Solution Approach 1:
The brake force is dynamically controlled rather than fixed. During automatic steering, the brake applies sufficient force to prevent handwheel movement and ensure feedback suppression. When the driver activates the steering unit, the brake force is immediately reduced or released, allowing the steering shaft to move freely. This dynamic force adjustment maintains both feedback suppression effectiveness and steering mode switching capability.
Solution Approach 2:
The braking torque parameter is changed based on the operating mode. The control device adjusts the brake's clamping force parameter: high during automatic steering for effective feedback suppression, and low or zero when the steering unit is activated to allow driver control. This parameter change enables the system to maintain feedback suppression effectiveness while adapting to different steering modes as needed.
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
This solution allows the steering handwheel to have priority over the steering valve in all operating situations, enabling driver control when needed, while maintaining feedback properties for driving comfort without unnecessary steering handwheel movement.
Implementation Method 1
the activation sensor is a torque sensor. A torque sensor determines when a force is acting in the rotation direction
Implementation Method 2
an electrically activated brake is easily activated or deactivated
Data Source
AI summary
The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavored to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.