Gearbox Actuator Position Control via Inertia Observer
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Solution Overview
Problem
Hybrid gearboxes with sliding-type shift actuators lack mechanical synchronization means, requiring precise control of driving sources to manage speed differences for gear changes, but existing methods rely on physical sensors and are prone to errors due to noise in RPM measurements, leading to untimely deceleration or acceleration during gear shifts.
Innovation Solution
A method that estimates the inertia of the gearbox shaft by integrating the torque and speed measurements, using a low-pass filter to smooth the signal and an inertia observer to detect failures, ensuring the convergence of measured and observed speeds without relying on derivative operations that amplify noise, thereby securing the neutral position and preventing untimely gear changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical sensors are used to detect gearbox actuator position, then measurement information is available, but device complexity and cost increase
Solution Approach 1:
The patent replaces physical sensors with a mathematical observer that estimates actuator position and neutral state based on torque and speed measurements. The inertia observer uses the relationship between torque, speed, and inertia to infer gearbox state without mechanical sensors, thereby reducing device complexity while maintaining measurement capability
Solution Approach 2:
The patent introduces an intermediate computational model (inertia observer) that mediates between available measurements (torque, speed) and the desired information (actuator position, neutral state). This observer acts as a virtual sensor that processes existing data to provide the needed measurement information
2Measurement precision
If derivative operations are used to calculate acceleration from speed measurements, then acceleration information is obtained, but noise amplification occurs
Solution Approach 1:
Instead of calculating acceleration from speed (derivative operation that amplifies noise), the patent inverts the approach by using torque and speed directly in the inertia observer equations. The observer estimates acceleration implicitly through the relationship T = J*α + B*ω, avoiding explicit differentiation of noisy speed signals
Solution Approach 2:
The inertia observer uses feedback from torque and speed measurements to continuously estimate the system state. By feeding back the estimated inertia and comparing it with expected values, the system reliably determines neutral position without amplifying noise through derivative operations
3Productivity
If clutch release is not ensured during gear change, then synchronization can proceed, but untimely deceleration or acceleration occurs
Solution Approach 1:
The inertia observer continuously monitors the gearbox actuator position before the actual gear engagement occurs. By detecting the neutral position in advance through inertia estimation, the system ensures clutch release is properly executed before synchronization begins, preventing untimely deceleration or acceleration during the gear change
Solution Approach 2:
The system uses feedback from the inertia observer to verify clutch release status and actuator position throughout the gear change process. This continuous monitoring ensures that synchronization only proceeds when the clutch is properly released, maintaining reliable gear shift execution
Data Source
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AI summary
The invention relates to a method for controlling the position of a gearbox actuator in charge of engaging a ratio at the end of a preliminary phase of synchronizing two shafts of the gearbox via a torque-driven traction machine to bring the speed difference of the two shafts within a range enabling the mechanical coupling thereof. The invention is, characterized in that it is ensured that the speed measured on one of the two shafts converges with a speed observed as a function of the inertia value observed on this shaft relative to the value expected as a function of the gearbox actuator, and of an estimation of the machine torque.