Transmission Shift Torque Error Discrimination for NVH Control
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Solution Overview
Problem
Conventional vehicle transmission control systems incorrectly assume that torque errors are due to clutch torque, leading to inappropriate adjustments and potentially worsening shift quality, as they fail to distinguish between engine/motor torque and transmission clutch torque errors.
Innovation Solution
A control system that uses a transmission model to differentiate between torque generating system errors and transmission clutch torque errors by measuring and analyzing the accelerations of the output shafts, employing third-order Kalman filtering and linear algebra to adjust clutch actuation accordingly, thereby mitigating noise, vibration, and harshness (NVH) during shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional transmission control systems assume torque errors are due to clutch torque and only adapt clutch torque/pressure, then the control system maintains simplicity, but the shift quality deteriorates when the actual error source is engine/motor torque
Solution Approach 1:
The patent segments the torque error analysis into two distinct sources: engine/motor torque errors and transmission clutch torque errors. By using two separate acceleration sensors (one on the torque generating system output shaft and one on the transmission output shaft) and applying a transmission model with linear algebra, the system can independently identify and compensate for errors from each source, rather than assuming all errors come from the clutch.
Solution Approach 2:
The system implements feedback by continuously monitoring accelerations of both the torque generating system output shaft and transmission output shaft during shift operations. The controller compares measured accelerations with target accelerations, identifies error sources through the transmission model, and adjusts clutch torque/pressure accordingly to compensate for identified errors, creating a closed-loop control system that adapts to actual error sources.
2Reliability
If the control system uses a transmission model with two acceleration sensors to discriminate error sources, then shift quality improves through accurate error identification, but device complexity increases
Solution Approach 1:
The system uses the existing transmission components and sensors in a novel way. The two acceleration sensors measure accelerations that already exist during normal operation, and the transmission model uses the inherent mechanical relationships within the transmission to identify error sources. The system essentially uses its own operational data and structural characteristics to diagnose and correct its own performance issues without requiring external diagnostic equipment.
Solution Approach 2:
The patent changes the approach from assuming a single error source to analyzing multiple torque parameters (engine/motor torque and clutch torque) separately. By introducing acceleration measurements as a new parameter and using the transmission model to relate these accelerations to torque errors through linear algebra, the system transforms the control approach from simple clutch adaptation to multi-parameter error discrimination and compensation.
Data Source
AI summary
Control systems and methods for a vehicle transmission initiate a shift operation of the transmission and, during the transmission shift operation, determine an acceleration of a torque generating system output shaft based on its measured rotational speed and determine an acceleration of the transmission output shaft based on its measured rotational speed, identify an error source using a transmission model that maps differences between the determined and target accelerations back to torque generating system error and/or transmission clutch torque error and, based on the identified error source, adjust the actuation of at least some of the plurality of clutches to compensate for the torque generating system error and/or transmission clutch torque error to mitigate or eliminate noise/vibration/harshness (NVH) caused by the transmission shift operation.