Lash Crossing Detection Using Shaft Torque Sensor
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Solution Overview
Problem
Current methods for detecting lash crossing in motor vehicle drivelines, particularly using speed sensors, face challenges such as numerical and resolution issues, sensitivity to noise, and accuracy problems at low speeds, leading to difficulties in reliably predicting and mitigating drivability issues caused by backlash.
Innovation Solution
A method involving the measurement of torque and twist across torsional discontinuities, using a ratio of driveline twist to torque and inverse driveline stiffness to determine backlash zones, and adjusting reference values based on measured twist and torque, which combines torque and speed sensor data to improve detection accuracy and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If speed sensors are used to detect lash crossing, then the detection method is simple and widely available, but numerical and resolution problems occur especially at low speeds and the system is sensitive to noise factors
Solution Approach 1:
The patent combines multiple measurement approaches (speed sensor data, torque sensor data, and driveline twist calculations) into a unified detection system. This integration allows the system to leverage the simplicity of speed sensors while compensating for their limitations through additional measurement dimensions, thereby resolving the contradiction between ease of manufacture and measurement precision.
Solution Approach 2:
The patent introduces torque sensors and driveline twist calculations as intermediary measurements that bridge the gap between simple speed sensor data and accurate lash crossing detection. These intermediaries provide additional information that helps resolve numerical and resolution problems, especially at low speeds, without requiring complete replacement of the existing sensor system.
2Ease of operation
If speed sensor position readings are used for torque estimation, then the method is straightforward, but resolution problems and sensitivity to synchronization errors and noise occur
Solution Approach 1:
The patent merges speed sensor position readings with torque sensor measurements and driveline twist calculations to create a more reliable torque estimation method. This combination maintains the straightforward operation of using available sensors while significantly improving reliability by compensating for resolution problems and noise sensitivity through multiple measurement sources.
Solution Approach 2:
The patent implements feedback mechanisms where torque sensor measurements and driveline twist data are used to validate and correct torque estimates derived from speed sensor readings. This feedback loop enhances reliability by continuously comparing multiple estimation approaches and adjusting for synchronization errors and noise, while maintaining the simplicity of the original method.
3Adaptability or versatility
If traditional speed sensor-based methods are used, then existing sensors can be utilized, but detection accuracy deteriorates at low speeds and in noisy conditions
Solution Approach 1:
The patent combines existing speed sensor data with additional torque sensor measurements and driveline twist calculations to maintain adaptability to existing sensor systems while dramatically improving backlash detection precision. The merged approach allows the system to work with available sensors across various operating conditions, particularly enhancing performance at low speeds and in noisy environments.
Solution Approach 2:
The patent adds new measurement dimensions (torque magnitude and driveline twist) to the traditional speed sensor approach. This dimensional expansion enables accurate backlash detection across all operating conditions, particularly where traditional single-dimension methods fail, while still兼容 with existing sensor infrastructure.
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 effectively avoids the limitations of speed sensor-based methods by providing robust backlash detection and adjustment, reducing sensitivity to noise and improving drivability control, especially at low speeds and in noisy conditions.
Implementation Method 1
measuring torque transmitted between components across a torsional discontinuity
Implementation Method 2
the shaft twist to torque relationship could have been expressed using the torsional spring equation (Hooke's law): t=Ks q
Data Source
AI summary
A method for detecting backlash and adjusting driveline variables, includes measuring torque transmitted between components across a torsional discontinuity, measuring driveline twist across the discontinuity, using a ratio of driveline twist divided by torque and an inverse of driveline stiffness to determine whether the driveline is entering, exiting or in a backlash zone, and using measured driveline twist and torque at the backlash zone to adjust reference values of driveline twist and torque.