Electromagnetic Damper Load Control for Vehicle Suspension
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Solution Overview
Problem
Existing vehicle suspension systems using electromagnetic dampers face challenges in minimizing system size and simplifying control mechanisms while maintaining ride quality and road tracking performance, especially when encountering transient inputs like short bumps, leading to the need for additional hydraulic dampers and complex control mechanisms.
Innovation Solution
A vehicle suspension system incorporating an electromagnetic damper with a control unit that computes demand loads for both the sprung and unsprung members, adjusting the target load based on resonance frequencies and cornering conditions to optimize damping forces, thereby minimizing system size and simplifying control by reducing the absolute value of the sprung member demand load when in the unsprung member resonance frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If damping force control is restrained in frequency range lower than unsprung member resonance frequency to prioritize ride quality, then skyhook control dominance is improved, but road tracking performance deteriorates when transient input is applied
Solution Approach 1:
The control system dynamically adjusts the sprung member demand load based on the detected sprung member frequency. When the frequency is determined to be in the unsprung member resonance frequency range, the system automatically reduces the sprung member demand load to allow unsprung member demand load to dominate, improving road tracking performance while maintaining ride quality control in other frequency ranges.
2Reliability
If additional hydraulic damper is provided in parallel with electromagnetic damper to handle transient inputs, then road tracking performance is improved, but system size increases
Solution Approach 1:
The electromagnetic damper is designed to perform multiple functions by dynamically adjusting its control strategy based on operating conditions. It can provide both ride quality control (skyhook control) and road tracking control (damping control) by switching between different control modes, eliminating the need for separate hydraulic dampers and reducing overall system size.
Solution Approach 2:
The system changes the control parameters of the electromagnetic damper based on the detected sprung member frequency. By adjusting the sprung member demand load parameter dynamically, the single electromagnetic damper can adapt to different road conditions and frequency ranges, providing both ride quality and road tracking performance without requiring additional components.
3Reliability
If additional hydraulic damper is provided in parallel with electromagnetic damper to handle transient inputs, then road tracking performance is improved, but control mechanism complexity increases
Solution Approach 1:
The control system uses dynamic frequency detection and adaptive load adjustment to manage different control modes. By continuously monitoring the sprung member frequency and automatically adjusting the sprung member demand load, the system achieves both ride quality and road tracking performance with a single unified control mechanism, avoiding the complexity of coordinating multiple dampers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances both ride quality and road tracking performance by allowing the electromagnetic damper to generate appropriate damping forces without the need for additional dampers, reducing system size and complexity, and adapting to various driving conditions.
Implementation Method 1
an electromagnetic damper (7) provided with a sprung member (8) and an unsprung member (9) of a vehicle (1) to apply a drive force and a damping force between the sprung member and the unsprung member
Data Source
AI summary
A vehicle suspension system (3) includes an electromagnetic damper (7) provided with a sprung member (8) and an unsprung member (9) to apply a drive force and a damping force between the sprung member and the unsprung member, and a control unit (10) for controlling the electromagnetic damper. A target load for the electromagnetic damper is determined based on the unsprung member demand load that attenuates a vertical vibration of the unsprung member, and the sprung member demand load that restrains a vertical displacement of the sprung member. An absolute value of the sprung member demand load is reduced when a sprung member frequency is in an unsprung member resonance frequency range.