Active Steering Torque Phase Control for Nibble Cancellation
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Solution Overview
Problem
Steering nibble, a rotational vibration experienced by vehicle drivers due to front wheel imbalances, is not effectively mitigated by existing technologies, leading to an undesirable driving experience.
Innovation Solution
An active steering system that includes an electric motor coupled to a steering column and a computer programmed to isolate a nibble signal, applying a phase shift based on vehicle-wheel frequency using an all-pass filter or time delay to generate a motor torque that cancels out the nibble, thereby reducing its magnitude and frequency across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional steering systems are used without active compensation, then the steering system structure remains simple, but steering nibble vibrations are not effectively reduced
Solution Approach 1:
The system applies preliminary anti-action by generating a compensatory torque signal that is opposite in phase to the detected nibble vibration signal. This compensatory torque is applied in advance to counteract the harmful vibrations before they reach the steering wheel, effectively reducing steering nibble while maintaining system complexity at an acceptable level through electronic control rather than mechanical modifications.
2Object-affected harmful factors
If phase compensation is applied to reduce steering nibble, then steering nibble is reduced across a wide range of frequencies, but the system requires complex phase compensation algorithms
Solution Approach 1:
The system utilizes mechanical vibration principles by generating a compensatory torque that vibrates at the same frequency as the detected nibble signal but with opposite phase. This vibrational approach allows the system to cancel out harmful vibrations across a wide frequency range through resonance compensation, achieving effective nibble reduction without requiring overly complex algorithms.
3Object-affected harmful factors
If active steering control is implemented to cancel nibble, then steering nibble is reduced, but additional sensors and control systems are required
Solution Approach 1:
The system implements feedback by continuously monitoring the steering column torque through an existing torque sensor and using this information to generate real-time compensatory torque signals. The feedback loop processes the detected nibble vibrations and adjusts the compensatory torque accordingly, enabling effective nibble reduction while utilizing existing system components to minimize additional hardware requirements.
4Measurement precision
If torque sensor data is processed to isolate nibble signal, then accurate nibble detection is achieved, but signal processing complexity increases
Solution Approach 1:
The system applies preliminary action by pre-processing the torque sensor data through calibrated filtering algorithms that are tuned to detect nibble vibrations at specific frequencies. This preliminary signal processing prepares the data in advance for accurate nibble isolation, achieving high detection precision while keeping the processing complexity manageable through pre-established filter parameters and algorithms.
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 system effectively reduces steering nibble across various frequencies, improving the driving experience by minimizing vibrations transmitted to the steering wheel, regardless of the vehicle's wheel speed.
Implementation Method 1
instruct the electric motor to output a motor torque based on the nibble signal shifted by a phase shift, the phase shift based on a vehicle-wheel frequency
Implementation Method 2
an electric motor drivably coupled to a steering column... instruct the electric motor to output a motor torque
Data Source
AI summary
A steering system includes an electric motor drivably coupled to a steering column, and a computer communicatively coupled to the electric motor. The computer is programmed to isolate a nibble signal in data representing a torque of the steering column, and instruct the electric motor to output a motor torque based on the nibble signal shifted by a phase shift, the phase shift based on a vehicle-wheel frequency.