Motor-Adjustable Steering Column Control for Noise Reduction
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Solution Overview
Problem
Existing motor-adjustable steering column control systems are plagued by noise issues due to frequency modulations caused by tolerance deviations and external influences, leading to an inadequate acoustic impression and manufacturing quality perception.
Innovation Solution
A control method for a motor-adjustable steering column that regulates the adjustment drive using a control unit based on a predetermined speed profile, with a sensor determining the adjustment speed and a control loop correcting inconsistencies, employing a PID controller and pulse width modulation to maintain a constant adjustment speed and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the actuating drive operates at high speed to improve adjustment productivity, then the adjustment speed increases, but noise in the audible frequency range increases due to frequency modulations
Solution Approach 1:
The patent applies dynamics by making the actuating drive speed variable rather than constant. The control unit dynamically adjusts the rotational speed of the electric motor during the adjustment process, accelerating at the beginning and decelerating near the target position. This dynamic speed variation reduces noise in the audible frequency range while maintaining high overall adjustment speed, resolving the contradiction between productivity and noise generation.
Solution Approach 2:
The patent implements periodic action through controlled acceleration and deceleration phases during the adjustment process. By periodically varying the speed profile (accelerating then decelerating), the system avoids continuous high-speed operation that generates audible noise, while still achieving fast overall adjustment. This periodic variation in speed eliminates the harmful frequency modulations.
2Reliability
If a complex control system with disturbance feedforward is used to reduce speed dependence on external parameters, then speed stability improves, but control inertia increases making it impossible to counteract frequency modulations
Solution Approach 1:
The patent applies preliminary action by pre-defining speed profiles and using feedback control to adjust the actuating drive speed in real-time. Instead of relying on complex disturbance feedforward calculations, the system proactively controls the speed based on predetermined profiles and actual position feedback, achieving both speed stability and rapid response to counteract frequency modulations.
Solution Approach 2:
The patent implements feedback control where the control unit continuously monitors the actual position of the actuating unit and adjusts the motor speed accordingly. This feedback mechanism provides both speed stability and rapid response capability, eliminating the control inertia problem associated with complex disturbance feedforward systems while maintaining reliability.
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 solution significantly shortens the response time to changing conditions, corrects irregularities, and improves the acoustic impression by maintaining a constant fundamental frequency, reducing noise and enhancing the overall quality of the steering column adjustment.
Implementation Method 1
The actuating drive comprises an electric motor operatively connected to a spindle drive
Implementation Method 2
a spindle drive, which converts the rotary motion of the electric motor's rotor shaft into a translational motion
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for operating a motor-adjustable steering column (1) for a motor vehicle, comprising a supporting unit (2) and an actuation unit (3), which is supported by the supporting unit (2) and in which a steering spindle (33) is rotatably mounted and which can be adjusted relative to the supporting unit (2) by means of at least one adjustment drive (5, 6), the adjustment drive (5, 6) being controlled by means of a control unit (10) and an adjustment speed (9) brought about by the adjustment drive (5, 6) being determined on the basis of measurement data of a sensor (8), the control unit (10) controlling the adjustment drive (5, 6) in a control loop on the basis of a control deviation between a specifiable speed profile and the determined adjustment speed (9). The invention also relates to a motor-adjustable steering column (1) designed for implementation of the method.