CVP Hub Passive Calibration Using Ratio and Backlash Detection
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Solution Overview
Problem
Current calibration methods for continuously variable planetary (CVP) systems in vehicles are time-consuming and require excessive human interaction, leading to potential damage from actuator overloading due to lack of knowledge about physical end stops and varying manufacturing tolerances.
Innovation Solution
A passive calibration method using an Automatic Hub Interface (AHI) that detects transmission speed ratios and shift driver positions through minimal user input, allowing for automatic detection of full underdrive and overdrive positions, and continuous monitoring to adjust and maintain optimal calibration during vehicle operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used to determine absolute positions and transmission speed ratios, then calibration accuracy can be achieved, but the process becomes time-consuming and requires excessive human interaction
Solution Approach 1:
The system performs self-calibration by automatically detecting transmission speed ratios and shift driver positions during normal operation. The AHI (Automatic Hub Interface) monitors the relationship between actuator position and actual transmission ratio, automatically adjusting calibration parameters without requiring user intervention or manual procedures, thus resolving the contradiction between accuracy and time consumption.
2Ease of operation
If the actuator is used to adjust transmission speed ratio without calibration information, then the system can operate, but the actuator may overload by hitting physical end stops and causing damage
Solution Approach 1:
The system implements feedback by continuously monitoring the relationship between actuator position and transmission speed ratio. The AHI detects when the transmission mechanism approaches physical end stops by monitoring for stalling events or abnormal current draw, and automatically adjusts the actuator's travel limits to prevent overloading, thus maintaining both operability and reliability.
Solution Approach 2:
The system performs preliminary calibration actions by automatically establishing safe operating boundaries for the actuator before normal operation begins. The AHI detects physical end stops and backlash characteristics during initial operation, pre-configuring the control system to prevent future overloading, thereby ensuring reliability while maintaining ease of operation.
3Measurement precision
If manufacturing tolerances and aging are accounted for through individual calibration, then system accuracy is maintained, but the calibration process becomes complex and requires user intervention
Solution Approach 1:
The system automatically adapts to manufacturing tolerances and aging effects through continuous self-calibration. The AHI monitors actual transmission speed ratios against expected values and automatically adjusts calibration parameters to compensate for wear and manufacturing variations, maintaining accuracy without requiring complex user-driven calibration procedures.
Data Source
AI summary
A continuous variable planetary (CVP) system includes a CVP hub, which includes a shift mechanism including a shift driver element, and a processing server system to calibrate the CVP system and detect errors within the CVP system. The processing server system performs continuously monitoring or obtaining a transmission speed ratio of the CVP hub. Upon detecting that the transmission speed ratio reaches a particular value, the processing server system records a corresponding position of the shift driver. The processing server system calibrates the CVP system based on the particular value, the corresponding position, and a known relationship between transmission speed ratios and positions of the shift mechanism. The processing server system determines or verifies a full underdrive (FUD) position by iteratively reducing a transmission speed ratio from the particular value until an onset of a backlash condition is detected and determines or verifies a full overdrive (FOD) position.