Bearing Load Sensing via Dual-Path Signal Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing load sensing technologies for rolling element bearings face challenges in accurately determining mechanical loads due to variations in sensor signal amplitudes caused by the high hardness of bearing components and small diameter rolling elements, leading to fluctuations that are not accounted for by current filtering methods, which neglect dynamic contributions to the load.
Innovation Solution
A load determining system that combines a first signal processing path for low-pass filtering to determine an average contribution to the mechanical load and a second signal processing path for band-pass filtering to determine a dynamic contribution, with cut-off frequencies adjusted based on the ball-pass frequency to account for both low-frequency variations and high-frequency dynamic changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current filtering methods are used to process sensor signals, then the processing is simple, but the measurement precision deteriorates because dynamic contributions to the load are neglected
Solution Approach 1:
The sensor signal processing is segmented into two distinct paths: a first signal processing path that applies low-pass filtering to determine average load contributions, and a second signal processing path that applies band-pass filtering to determine dynamic load contributions. This segmentation allows each path to be optimized for its specific function while collectively achieving comprehensive load measurement.
Solution Approach 2:
The system dynamically adapts the cut-off frequencies of the filters based on the ball-pass frequency. The first cut-off frequency is set substantially equal to the ball-pass frequency, while the second cut-off frequency is set higher than the ball-pass frequency. This dynamic frequency adaptation ensures accurate capture of load variations across different operating conditions.
2Measurement precision
If low-pass filtering is applied to determine average load contribution, then low-frequency variations are captured, but high-frequency dynamic changes are lost
Solution Approach 1:
The signal processing is divided into two segments: the first signal processing path uses low-pass filtering with a cut-off frequency substantially equal to the ball-pass frequency to extract average load contributions, while the second signal processing path uses band-pass filtering to extract dynamic load contributions. This segmentation ensures that both average and dynamic information are preserved and processed appropriately.
Solution Approach 2:
The system dynamically adjusts the cut-off frequencies based on operating conditions. The first cut-off frequency is set substantially equal to the ball-pass frequency to capture low-frequency variations, while the second cut-off frequency is set higher to preserve high-frequency dynamic information. This dynamic frequency selection optimizes the capture of different load components.
3Measurement precision
If band-pass filtering is applied to determine dynamic load contribution, then high-frequency dynamic changes are captured, but low-frequency variations are lost
Solution Approach 1:
The signal processing is segmented into two parallel paths: the second signal processing path applies band-pass filtering with cut-off frequencies set to capture dynamic load contributions, while the first signal processing path simultaneously applies low-pass filtering to capture average load contributions. This segmentation allows both frequency ranges to be processed independently and then combined for comprehensive load determination.
4Device complexity
If the cut-off frequencies are fixed, then the filter design is simple, but the measurement precision deteriorates when operating conditions vary
Solution Approach 1:
The system dynamically adapts the cut-off frequencies of both filters based on the ball-pass frequency, which varies with operating conditions. The first cut-off frequency is set substantially equal to the ball-pass frequency, while the second cut-off frequency is set higher than the ball-pass frequency. This dynamic frequency adaptation ensures optimal performance across varying operating conditions without requiring complex adjustable filter designs.
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
This approach allows for a more accurate determination of the total mechanical load on rolling element bearings by averaging out fluctuations and accounting for dynamic contributions, improving the precision of load measurement by considering both average and dynamic contributions simultaneously.
Implementation Method 1
The load on the rolling element bearing causes an elastic deformation of the rolling element bearing. The deformation is sensed by one or more strain sensors accommodated at the rolling element bearing.
Implementation Method 2
The first signal processing path is configured for low-pass filtering the sensor output with a first cut-off frequency; and for processing the low-pass filtered sensor output as representative of the local deformation induced by a passing of the rolling elements past the specific location
Implementation Method 3
The second signal processing path is configured for band-pass filtering the sensor output with a second cut-off frequency, substantially equal to the first cut-off frequency, and with a third cut-off frequency higher than the second cut-off frequency
Implementation Method 4
The local deformation changes dynamically as a result of the repetitive passing of rolling contact forces (also referred to as 'Hertzian contact forces'). The repetitive passing of the rolling contact forces is characterized by the ball-pass frequency.
Data Source
AI summary
The mechanical load on a rolling element bearing is determined from the deformation of the rolling element bearing. The local deformation caused by the rolling contact forces is used to determine an average contribution to the mechanical load in order to average out the effect on the deformation as a result of the spread in diameter of the rolling elements of the bearing. The global deformation of the rolling element bearing is determined to calculate a dynamic contribution to the mechanical load. The dynamic contribution takes into account the variations of the mechanical load on the relevant time-scales that have been omitted from the average contribution as a result of the averaging operation. The total mechanical load is the sum of the average contribution and the dynamic contribution.