Steering Torque Feedback Control With a Single Torsion Bar
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heavy vehicles and farming vehicles face challenges with steering systems due to the need for high steering assistance, which often results in weak column stiffness, poor steering response, and conflicts between assistance and disturbances, leading to issues like noise suppression and torque steer.
Innovation Solution
A steering system with a single torsion bar equipped with a torsion-bar torque sensor and an electrical feedback torque actuator above the hydraulic assistance actuator, using closed-loop current control to measure and control the torque, allowing for improved controllability and steering feel without the need for additional torsion bars or torque sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two assistance actuators are used in series (hydraulic actuator plus feedback torque actuator), then controllability for functions like Lane Keeping Aid is improved, but column stiffness becomes approximately half its stiffness compared to using only one torsion bar, leading to poor steering response
Solution Approach 1:
The patent extracts the torque measurement function from a separate sensor and integrates it into the existing single torsion bar structure. By using the torsion bar both for mechanical assistance and for torque sensing, the system eliminates the need for a second torsion bar while maintaining full controllability through the feedback torque actuator.
Solution Approach 2:
The single torsion bar serves dual functions: providing mechanical assistance through the hydraulic actuator and serving as the sole torque sensor for the feedback control system. This multi-functionality reduces component count while maintaining both steering response and controllability.
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 configuration enhances steering controllability and feel by accurately measuring and applying torque, reducing the need for multiple torsion bars and sensors, thereby improving the overall steering experience while minimizing disturbances.
Implementation Method 1
only the torsion bar of the steering assistance actuator comprises a torsion-bar torque sensor
Implementation Method 2
the feedback torque actuator does not comprise neither a torsion bar nor a torsion bar torque sensor
Data Source
AI summary
The present invention relates to a system and a method for controlling a feedback torque actuator in a steering system. The steering system comprises a steering assistance actuator (140) with a torsion bar (128) and a feedback torque actuator (130) with an Electric Control Unit, ECU, for giving feedback to a driver, a steering wheel (120) to which the driver applies a driver torque, TD. Only the torsion bar of the steering assistance actuator (140) comprises a torsion-bar torque sensor, and a target torque for the feedback torque actuator (130) is a target steering feel torque compensated for torque sensed in the torsion bar (128).