Motorized Steering Column Speed Feedback for Voltage Saturation Control
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Solution Overview
Problem
The predefined adjustment speed of motor-adjustable steering columns in vehicles often results in voltage signals exceeding the supply voltage, leading to saturation of the onboard electrical system, noticeable speed fluctuations, and audibly oscillating motor noise due to insufficient operating voltage.
Innovation Solution
A method and control unit that adjust the setpoint value of the adjustment speed based on actual speed detection, reducing it until the voltage signal falls below the maximum supply voltage to prevent saturation and compensate for speed fluctuations using pulse width modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the predefined adjustment speed is used to drive the electric motor, then the desired adjustment speed is achieved, but the voltage signal exceeds the supply voltage causing saturation and speed fluctuations
Solution Approach 1:
The patent applies dynamics by making the voltage signal dynamically adjustable based on actual operating conditions. The controller continuously monitors the actual adjustment speed and adjusts the voltage signal amplitude accordingly, transitioning from a static predefined voltage to a dynamic adaptive voltage that prevents saturation while maintaining desired speed performance.
Solution Approach 2:
The patent implements feedback control by detecting the actual adjustment speed of the actuating unit and using this information to adjust the voltage signal. The controller compares the actual speed with the desired speed and modifies the voltage amplitude to eliminate deviations, thereby preventing voltage saturation and ensuring reliable operation.
2Reliability
If the voltage signal is reduced to stay within supply voltage limits, then saturation is avoided, but the adjustment speed falls below the desired speed
Solution Approach 1:
The system dynamically adjusts the voltage signal amplitude based on real-time feedback about actual adjustment speed. Rather than using a fixed reduced voltage, the controller continuously optimizes the voltage level to maintain desired speed while staying within supply voltage limits, resolving the trade-off between reliability and speed performance.
Solution Approach 2:
The patent changes the voltage parameter dynamically based on operating conditions. By adjusting the voltage amplitude in response to feedback about actual speed and comparing it with desired speed, the system optimizes the voltage parameter to achieve both reliability and desired adjustment speed simultaneously.
3Productivity
If the predefined adjustment speed is maintained, then the adjustment function is efficient, but audible oscillating motor noise and speed fluctuations occur
Solution Approach 1:
The feedback control system detects actual adjustment speed and adjusts the voltage signal to eliminate speed fluctuations. By continuously monitoring and correcting speed deviations, the system maintains efficient adjustment while preventing the oscillating motor noise that would otherwise occur during saturation conditions.
Solution Approach 2:
The dynamic voltage adjustment prevents the motor from operating in saturation, which eliminates the oscillating noise. The system maintains high productivity by adapting the voltage in real-time to ensure smooth, fluctuation-free motor operation throughout the adjustment process.
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
Ensures uniform adjustment movement and reduced motor noise, enhancing the acoustic quality and perceived processing quality for vehicle occupants by stabilizing the adjustment speed within the available supply voltage limits.
Implementation Method 1
compensate for speed fluctuations using pulse width modulation
Data Source
AI summary
The disclosure relates to a method for operating an adjustment drive of a motor-adjustable steering column for a motor vehicle, said steering column comprising an actuating unit with a rotatably mounted steering spindle, to which a steering wheel is attached, wherein the actuating unit is adjustable by at least one adjustment drive for setting a longitudinal position and/or height position of the steering wheel, wherein in the method: a) a setpoint value of an adjustment speed of the actuating unit is predefined; b) on the basis of the setpoint value, the at least one adjustment drive is driven with a voltage signal by way of at least one controller; c) an actual value of the adjustment speed of the actuating unit is detected after a predetermined time period and is compared with the setpoint value; and d) the setpoint value is reduced depending on the result of the comparison between setpoint value and actual value until the voltage signal for driving the adjustment drive lies below the maximum value of a supply voltage, in particular an onboard electrical system voltage of the motor vehicle.