CVP Hub Passive Calibration Using Backlash Detection
Find Innovative SolutionsGenerate Solutions
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 excessive force on physical end stops.
Innovation Solution
A passive calibration method using an Automatic Hub Interface (AHI) that monitors transmission speed ratios and shift driver positions, allowing for calibration during normal vehicle operation with minimal user input, and avoiding physical end stops by detecting backlash and adjusting accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used to establish 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 backlash through iterative actuator movements and monitoring transmission speed ratios. The AHI independently identifies FUD and FOD positions without requiring external calibration tools or extensive human intervention, enabling the system to calibrate itself during normal operation.
Solution Approach 2:
The calibration process performs preliminary actions by first identifying backlash through iterative downshifting and upshifting movements before establishing the final calibration parameters. This preliminary detection of mechanical clearances allows subsequent calibration steps to be more accurate and efficient.
2Adaptability or versatility
If the actuator continuously operates without calibration to adjust transmission speed ratios, then the system remains adaptable, but physical end stops may be damaged due to excessive force
Solution Approach 1:
The system uses feedback from transmission speed ratio sensors to detect when the actuator approaches physical end stops. By continuously monitoring the relationship between actuator position and transmission speed ratio, the system identifies calibration parameters that prevent excessive force application, thereby protecting end stops while maintaining operational adaptability.
Solution Approach 2:
The calibration process establishes software limits and operational parameters beforehand that cushion against physical end stops. By pre-defining FUD and FOD positions through backlash detection, the system creates a protective buffer zone that prevents the actuator from applying excessive force to physical end stops during normal operation.
3Measurement precision
If manual calibration procedures are implemented to account for manufacturing tolerances and aging, then individual system accuracy is improved, but user experience deteriorates due to complex interaction requirements
Solution Approach 1:
The system automatically adapts to individual manufacturing variations and aging effects through self-calibration. The AHI independently detects backlash and establishes calibration parameters specific to each system's mechanical characteristics, eliminating the need for users to perform complex manual calibration procedures while maintaining individual system accuracy.
Solution Approach 2:
The calibration system dynamically adapts to changing mechanical conditions including manufacturing tolerances and aging. By continuously monitoring transmission speed ratios and actuator positions, the system adjusts calibration parameters to account for wear and manufacturing variations, maintaining accuracy without requiring user intervention.
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.