Rear Axle Steering Actuator Sensor Feedback for Thermal Compensation
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Solution Overview
Problem
Existing rear axle steering systems face challenges in accurately adjusting steering angles due to temperature-related deformations of components, which affect the actual steering angle compared to the target specification, leading to inconsistent vehicle handling.
Innovation Solution
Incorporating a rotor position sensor and a linear sensor into the actuator of a rear axle steering system, coupled with a control and analysis unit, to detect and compensate for thermal expansion of components by adjusting the steering angle based on known material-specific coefficients of thermal expansion, using a defined zero point and temperature data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal expansion of steering linkage is considered in the control method, then steering angle precision is improved, but device complexity increases due to additional sensors and control unit
Solution Approach 1:
The control unit receives signals from both the rotor position sensor and linear sensor, continuously monitors their readings, and adjusts the steering angle based on the comparison between expected and actual positions. This feedback mechanism compensates for thermal expansion effects dynamically, maintaining precision without requiring mechanical redesign.
Solution Approach 2:
Instead of using complex mechanical compensation mechanisms for thermal expansion, the patent substitutes a sensor-based detection and electronic control system. The rotor position sensor and linear sensor with control unit replace potential mechanical adjustment mechanisms, reducing mechanical complexity while achieving the same precision goal.
2Manufacturing precision
If two sensors (rotor position sensor and linear sensor) are used for detection, then steering angle accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The control unit serves multiple functions: it processes signals from the rotor position sensor, signals from the linear sensor, compares the readings, calculates thermal expansion effects, and generates correction signals. This multi-functionality consolidates what could be separate components into a single control unit, reducing overall system cost despite using two sensors.
Solution Approach 2:
The system uses the existing rotor position sensor (already present for motor control) and adds a linear sensor to create a self-compensating system. The control unit automatically performs the comparison and adjustment without external intervention, making the system self-correcting for thermal effects without requiring expensive manual calibration mechanisms.
3Reliability
If thermal expansion compensation is implemented, then vehicle handling consistency is improved, but energy consumption increases due to continuous sensor operation and control processing
Solution Approach 1:
The control unit continuously monitors both sensor signals and automatically adjusts the steering angle without interruption. This continuous operation ensures consistent vehicle handling across varying temperatures without requiring periodic manual adjustments or system shutdowns, maintaining reliability while using energy efficiently through continuous rather than intermittent operation.
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
Precise adjustment of steering angles is achieved, ensuring consistent vehicle handling by compensating for temperature-induced component deformations, thereby improving the accuracy and reliability of the rear axle steering system.
Implementation Method 1
in consideration of a thermal expansion of at least the steering linkage, operates the actuator in order to adjust the steering angle
Data Source
AI summary
The disclosure relates to a method for steering a vehicle via a rear axle steering system that includes an actuator having a steering linkage at least indirectly operable by a threaded drive and longitudinally displaceable within a chassis-fixed housing. The actuator includes a rotor position sensor for detecting a rotor position of a rotor of an electric motor designed for actuating the threaded drive and a linear sensor for detecting an axial position of a target arranged on the steering linkage. The two sensors are connected to a control and analysis unit configured to carry out a comparison between the rotor position and the axial position of the target when there is a defined zero point of an axial position of the steering linkage relative to the housing and, in consideration of a thermal expansion of at least the steering linkage, operating the actuator to adjust the steering angle.