Power Steering Differential Angle Sensor Actuator Control
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Solution Overview
Problem
Existing power steering assemblies for motor vehicles lack effective monitoring and control mechanisms to enhance driving safety and steering assistance, particularly in influencing steering force assistance characteristics independently of applied torque, which is crucial for advanced features like lane departure warning and haptic feedback.
Innovation Solution
A power steering assembly with a servo controller, a rotatable actuator, and a sensor system for measuring differential angles between the actuator and input/output shafts, allowing for real-time evaluation and monitoring of steering force assistance characteristics, eliminating the need for additional elasticity and steering angle sensors, and enabling self-test functionality and adjustment for optimal steering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor system for measuring differential angles is added to monitor steering assistance, then driving safety and control precision are improved, but device complexity increases
Solution Approach 1:
The differential angle sensor system serves multiple functions: it monitors steering assistance characteristics, detects actuator position, enables self-test functionality, and provides data for various driver assistance features. By making the sensor system multi-functional, the patent achieves improved reliability and safety without proportionally increasing device complexity, as a single sensor infrastructure supports multiple monitoring and control objectives.
Solution Approach 2:
The sensor system enables self-test functionality where the actuator can check the full functionality of the system by rotating through its adjustment range before the journey starts. This self-diagnostic capability improves reliability without requiring additional external monitoring systems, as the system monitors and tests itself using the same sensor infrastructure.
2Adaptability or versatility
If the actuator position is adjusted independently of applied torque to influence steering force assistance characteristics, then adaptability and control flexibility are improved, but device complexity increases
Solution Approach 1:
The patent implements a dynamic adjustment mechanism where the actuator can change the steering force assistance characteristics in real-time based on vehicle conditions (speed, load, steering angle). The torsion system between the input shaft and actuator allows dynamic adjustment of the valve actuator position, enabling variable steering assistance that adapts to different driving situations without requiring multiple fixed systems.
Solution Approach 2:
The system changes the steering force assistance characteristics by adjusting the relative angle between the actuator and output shaft, which modifies the valve opening characteristics. By changing the actuator position parameter independently of torque, the system achieves variable steering assistance with different characteristics (e.g., city mode, highway mode) using a single adjustable parameter rather than multiple fixed systems.
3Measurement precision
If a second elasticity (T-bar) is added between input shaft and output shaft for conventional torque sensing, then measurement capability is improved, but steering feel is worsened
Solution Approach 1:
The patent extracts the torque sensing function from the mechanical torsion bar system and relocates it to the differential angle sensor system. Instead of using a second physical elasticity element (T-bar) for torque measurement, the system uses sensors to measure the differential angle between shafts and calculates torque information, thereby avoiding the negative impact on steering feel while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical torque sensing system (second elasticity/T-bar) with an electronic sensor-based measurement system. The differential angle sensors measure angular positions and the control unit calculates torque information, substituting direct mechanical coupling with electronic measurement and calculation, thus preserving steering feel while achieving torque sensing capability.
4Measurement precision
If steering angle sensor is integrated close to steering wheel in steering column, then steering angle measurement accuracy is improved, but installation space and cost increase
Solution Approach 1:
The patent merges the steering angle measurement function with the existing differential angle sensor system near the steering gear. Instead of adding a separate steering angle sensor in the steering column, the system uses the same sensor infrastructure to measure angles between shafts, combining multiple measurement functions into a single sensor location and reducing overall system complexity and installation space requirements.
Data Source
AI summary
The invention relates to a power steering assembly for power steering motor vehicles, comprising an input shaft (21) for connection to a steering wheel, an output shaft (29) which is coupled to the input shaft (21) for operational engagement with a steering rod, the coupling between the input shaft (21) and the output shaft (29) permitting a relative rotation therebetween, a servo controller which has a rotatable final control element (24) that is in engagement with the output shaft (29) and is driven by the output shaft (29), the steering force assistance being controlled depending on the relative rotation between the input shaft (21) and the final control element (24), the engagement between the output shaft (29) and the final control element (24) providing for a relative displacement therebetween, the invention further comprising an actuator for relatively displacing the final control element (24) in relation to the output shaft (29) in order to influence the steering force assistance characteristic, a sensor (20, 28) for measuring at least one differential angle between the final control element (24) and the output shaft (29) or between the final control element (24) and the input shaft (21), and an evaluation unit for evaluating the measurement values that are provided by the sensor (20, 28).