Active Anti-rattle Noise Control in Electromechanical Steering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electromechanical power steering systems experience noise and vibration issues due to torque shocks from uneven roads, which current countermeasures attempt to mitigate through reduced play and restricted degrees of freedom, but result in increased friction, cost, and wear.
Innovation Solution
An electromechanical power steering system with a compensation controller that uses a torque sensor to detect reactive torque and generate a compensating signal to the electric motor, adjusting motor currents to counteract torque shocks, thereby reducing noise and vibration by ensuring the drive side works with the load, avoiding shocks in the transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If current countermeasures reduce play and restrict the snail's degrees of freedom, then rattling noise is reduced, but friction increases, installation space requirements increase, and wear increases
Solution Approach 1:
The patent replaces mechanical restriction measures (reducing play, restricting degrees of freedom) with an active control system using a compensation controller that generates counteracting torque signals. This substitutes mechanical complexity with electronic control, reducing physical constraints while eliminating rattling noise through active compensation of torque shocks in the 10-30 Hz frequency range.
Solution Approach 2:
The compensation controller continuously monitors torque shocks in the transmission and generates real-time compensating signals to the electric motor. This feedback mechanism detects torque variations caused by road irregularities and actively counteracts them, preventing rattling noise without requiring mechanical play reduction or degree of freedom restrictions.
2Object-affected harmful factors
If the snail's degrees of freedom are severely restricted, then rattling noise is reduced, but friction increases and wear increases
Solution Approach 1:
The patent replaces mechanical restriction measures (reducing play, restricting degrees of freedom) with an active control system using a compensation controller that generates counteracting torque signals. This substitutes mechanical complexity with electronic control, reducing physical constraints while eliminating rattling noise through active compensation of torque shocks in the 10-30 Hz frequency range.
Solution Approach 2:
The compensation controller anticipates and counteracts torque shocks before they propagate through the transmission to cause rattling. By detecting torque variations early and generating compensating signals, the system prevents the harmful effects (noise and wear) before they occur, rather than relying on mechanical restrictions that increase wear.
3Object-affected harmful factors
If mechanical restrictions are applied to reduce rattling, then noise is reduced, but installation space requirements increase
Solution Approach 1:
The patent replaces mechanical restriction measures (reducing play, restricting degrees of freedom) with an active control system using a compensation controller that generates counteracting torque signals. This substitutes mechanical complexity with electronic control, reducing physical constraints while eliminating rattling noise through active compensation of torque shocks in the 10-30 Hz frequency range.
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 effectively reduces noise and vibration by compensating for torque shocks in the 10-30 Hz frequency range, enhancing steering feel and reducing rattling noises without increasing friction or wear.
Implementation Method 1
a torque sensor which is arranged between an upper steering shaft connected to the steering wheel and the lower steering shaft and detects a steering torque applied by the driver and a torque reacting from the lower steering shaft to the upper steering shaft
Implementation Method 2
the control device has a compensation controller, which impresses a signal on the rotor of the electric motor as a function of the retroactive torque measured by the torque sensor, so that a relative movement between a drive side facing the electric motor and an output side facing the lower steering shaft, which is caused by the retroactive torque in the transmission, is compensated
Implementation Method 3
The ideal rotor angle and the required motor torque are calculated by vector control, transmitted electrically to the motor in the form of phase currents in the power stage and physically generated in the motor by the resulting magnetic fields
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an electromechanical motor vehicle steering system (1) having a steering pinion (5) which is connected to a lower steering shaft (4) and is in engagement with a toothed rack (6) which is mounted in a housing so as to slide along a longitudinal axis for the purpose of steering wheels (8), having an electric motor (9), which has a rotor, for the purpose of assisting the steering force, that drives the lower steering shaft (4) by means of a gear mechanism, having a torque sensor (11) which is arranged between an upper steering shaft (3) connected to the steering wheel and the lower steering shaft (4), and senses a steering torque (TTS) applied by the driver and a torque (TSTR) reacts from the lower steering shaft (4) to the upper steering shaft (3), and having a control device (14) which comprises a steering control system (12) and an engine closed-loop control system (13) of the electric motor (9), wherein the steering control system (12) calculates a motor setpoint torque (TD) and passes it on to the motor closed-loop control system (13), wherein the motor closed-loop control system (13) determines motor currents for operating the electric motor (9), wherein the control device (14) has a compensation controller which imposes a signal on the rotor of the electric motor (9) as a function of the reactive torque (TSTR) measured by the torque sensor (11), with the result that a relative movement, arising as result of the reactive torque (TSTR), in the gear mechanism between a drive side facing the electric motor (9) and an output side facing the lower steering shaft (4) is compensated.