Vehicle Damping Control With Phase-Advanced Unsprung Displacement
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Solution Overview
Problem
Current damping control methods for vehicles, particularly those using preview damping control, face challenges in effectively damping the sprung portion at medium and high frequencies, leading to increased energy consumption, actuator durability issues, and heat generation, when calculating the target damping control force as a value proportional to unsprung displacement or its derivative.
Innovation Solution
A damping control device and method that calculates the target damping control force as a value proportional to the road surface displacement related value with an advanced phase, which is closer to the sum of control components proportional to the time derivative and unsprung displacement, improving damping performance at frequencies equal to or higher than medium frequencies while reducing energy consumption and actuator stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target damping control force is calculated as a value proportional to the time derivative of unsprung displacement, then vibration components proportional to unsprung displacement can be damped, but the target damping control force increases in high-frequency range causing increased energy consumption and actuator stress
Solution Approach 1:
The patent changes the parameter relationship by calculating the target damping control force as proportional to unsprung displacement (z1) rather than its time derivative, and introduces phase advance to optimize the frequency response characteristics, thereby reducing high-frequency amplification while maintaining damping effectiveness
Solution Approach 2:
The patent dynamically adjusts the phase of the road surface displacement related value to advance it by a predetermined amount, creating a frequency-dependent control force that adapts to different vibration conditions without requiring direct measurement of high-frequency components
2Use of energy by moving object
If the target damping control force is calculated as a value proportional to unsprung displacement, then energy consumption is reduced, but vibration components proportional to time derivative of unsprung displacement cannot be damped
Solution Approach 1:
The patent transforms the control parameter from unsprung displacement alone to phase-advanced road surface displacement related value, which maintains the low energy consumption benefit while improving damping effectiveness across a broader frequency range through phase optimization
3Reliability
If the target damping control force is calculated as the sum of control components proportional to time derivative and unsprung displacement, then damping performance is improved, but device complexity and calculation complexity increase
Solution Approach 1:
The patent simplifies the control parameter relationship to a direct proportionality between target damping control force and phase-advanced road surface displacement related value, eliminating the need for complex derivative calculations while achieving improved damping performance through phase optimization
Solution Approach 2:
The patent applies phase advance to the road surface displacement related value in advance, preparing the control signal optimally before it is used to generate the damping control force, thereby achieving effective damping without requiring complex real-time derivative computations
Data Source
AI summary
A control unit configured to control a control force generating device configured to generate a control force for damping a sprung portion of a vehicle controls the control force generating device based on a target control force Fcit for damping the sprung portion when a wheel passes through a predicted wheel passing position. The control unit acquires an unsprung displacement z1i at the predicted wheel passing position, and calculates the target control force as a value proportional to an unsprung displacement z1ai that is the unsprung displacement z1i having a phase that has been advanced to advance a phase of a transfer function from the unsprung displacement z1i to the target control force by a phase advance amount larger than 0 degrees and smaller than 180 degrees.