Electromagnetic Suspension Spring Force Control
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Solution Overview
Problem
Existing electromagnetic suspension apparatuses lack the ability to adjust spring force in response to the stroke position of the electromagnetic actuator, which affects ride comfort and stability, especially on varying road slopes and load conditions.
Innovation Solution
Incorporating an information acquisition unit to process time-series information about the stroke position, filtering out low-frequency components and passing higher-frequency information, and a driving force control unit to adjust the target driving force, ensuring the spring force is weakened when the stroke position is in a neutral region, thereby improving ride comfort across different road slopes and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the spring constant of the spring member is increased to improve vehicle stability, then ride comfort deteriorates because the spring force becomes too stiff for neutral position adjustments
Solution Approach 1:
The patent applies dynamics by making the spring force adjustable rather than fixed. The driving force control unit dynamically modifies the spring force based on the stroke position detected by the information acquisition unit. When the stroke position indicates the vehicle is on neutral ground, the system weakens the spring force to improve ride comfort; when on slopes or under load, it maintains stronger spring force for stability. This dynamic adjustment resolves the contradiction between fixed spring stability and variable ride comfort needs.
Solution Approach 2:
The patent changes the parameter of spring force based on operating conditions. By detecting stroke position and determining whether the vehicle is on neutral ground, slopes, or under varying loads, the system adjusts the spring force parameter accordingly. This allows the same spring member to provide different effective spring constants depending on the situation, resolving the contradiction between needing high stability (high spring constant) and good ride comfort (low spring constant).
2Ease of operation
If the spring force is weakened to improve ride comfort on neutral ground, then vehicle stability deteriorates on slopes or under varying loads
Solution Approach 1:
The patent implements feedback by using the information acquisition unit to continuously monitor the stroke position of the electromagnetic actuator. This feedback information is processed by the driving force control unit, which determines whether the vehicle is on neutral ground, slopes, or under varying loads. Based on this feedback, the system automatically adjusts the spring force to maintain both ride comfort and stability appropriate for the current condition, preventing the deterioration of stability that would occur with permanently weakened spring force.
Solution Approach 2:
The system dynamically adjusts spring force based on real-time detection of operating conditions. Rather than using a fixed weak spring force that would compromise stability on slopes, the system activates weakened spring force only when neutral ground is detected, and maintains stronger force when slopes or load variations are detected. This dynamic behavior resolves the contradiction between ride comfort and stability.
3Ease of operation
If the electromagnetic actuator continuously adjusts spring force to maintain ride comfort under all conditions, then power consumption increases
Solution Approach 1:
The patent uses periodic action by having the information acquisition unit detect stroke position at specific intervals and only adjusting spring force when changes in operating conditions are detected. Rather than continuously adjusting spring force, the system periodically monitors conditions and makes adjustments only when necessary (when transitioning between neutral ground, slopes, or load conditions). This reduces power consumption while maintaining ride comfort under varying conditions.
Solution Approach 2:
The system applies partial action by weakening spring force only partially and only when needed (on neutral ground), rather than continuously or excessively adjusting spring force under all conditions. The driving force control unit applies corrections selectively based on detected conditions, reducing unnecessary power consumption while still improving ride comfort when the stroke position indicates neutral ground.
4Ease of operation
If the spring force is adjusted based on unprocessed stroke position information including low-frequency components, then unnecessary corrections occur on slopes causing instability
Solution Approach 1:
The patent applies taking out by extracting and removing the low-frequency components from the stroke position time-series information before processing. The information acquisition unit detects the full stroke position signal, but the driving force control unit extracts only the relevant higher-frequency components for spring force adjustment decisions. This extraction process removes the misleading low-frequency information that would indicate false slope conditions, preventing unnecessary spring force corrections and maintaining vehicle stability.
Solution Approach 2:
The patent uses an intermediary process (signal processing/filtering) between the raw stroke position detection and the spring force control decision. The intermediate step of removing low-frequency components acts as a mediator that filters out false information about slope conditions, allowing the system to make accurate spring force adjustments based only on relevant stroke position changes. This intermediary processing prevents instability caused by reacting to misleading low-frequency signals.
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 solution maintains good ride comfort regardless of the spring constant preset, road slope, vehicle load, and operational conditions, preventing instability and unnecessary power consumption.
Implementation Method 1
an electromagnetic actuator which is provided in parallel with a spring member between a vehicle body and a wheel of a vehicle and generates a driving force involving vibration damping of the vehicle body
Implementation Method 2
The electromagnetic actuator is configured to include a ball screw mechanism in addition to the electric motor. The electromagnetic actuator operates to generate the driving force involving the vibration damping of the vehicle body by converting rotational motion of the electric motor into linear motion of the ball screw mechanism
Data Source
AI summary
The electromagnetic suspension apparatus includes: an electromagnetic actuator provided in parallel with a spring member between a vehicle body and a wheel of a vehicle and configured to generate driving force involving vibration damping of the vehicle body; an information acquisition unit configured to acquire, through a high-pass filter, time-series information about a stroke position of the electromagnetic actuator; and an ECU configured to calculate target driving force of the electromagnetic actuator and use the calculated target driving force to execute driving force control of the electromagnetic actuator. The ECU corrects the target driving force such that when the stroke position on the basis of the high-pass-filter-processed time-series information, from which low-frequency components (steady state deviation) have been removed, is present in a neutral region including a neutral position, spring force of the spring member is made weaker than when the stroke position is present in a non-neutral region.