Suspension Controller Damping Force Current Regulation

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Solution Overview

Problem

Existing suspension controllers for vehicles fail to effectively adjust damping force in real-time due to limitations in current control methods, particularly in managing solenoid coil temperature and power supply fluctuations, leading to inefficiencies in damping force regulation.

Innovation Solution

A suspension controller system that includes a target current setting unit, current limitation setting unit, current detector, duty ratio setting unit, and current outputting unit, which dynamically adjusts the current limitation value based on detected current and duty ratio to optimize the damping force control, ensuring appropriate current supply to solenoids despite variations in power supply voltage and temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the duty ratio in PWM control is adjusted to control current supplied to the solenoid, then the damping force can be controlled, but the solenoid coil temperature increases and power supply fluctuations affect control precision

Engineering Contradiction:
Improvedamping force controlVSAvoidcontrol precision
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the actual current supplied to the solenoid is detected and compared with the target current. Based on this comparison, the duty ratio is adjusted to minimize the difference between target and actual current. This closed-loop feedback system compensates for power supply fluctuations and temperature effects, maintaining control precision while enabling effective damping force regulation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the duty ratio parameter in PWM control based on detected current values and target current requirements. By changing the duty ratio parameter in response to system conditions, the system maintains optimal current supply to the solenoid despite power supply fluctuations and temperature variations, thereby preserving control precision.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the current supplied to the solenoid is increased to improve damping force response, then the damping force control is enhanced, but the solenoid coil temperature increases

Engineering Contradiction:
Improvedamping force responseVSAvoidsolenoid coil temperature
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The patent employs dynamic current control where the target current and duty ratio are continuously adjusted based on system conditions and damping force requirements. This dynamic approach allows the system to provide sufficient current for rapid damping force response when needed while reducing current when full power is not required, thereby managing solenoid coil temperature through adaptive, condition-based control.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the duty ratio is adjusted to compensate for power supply voltage fluctuations, then the current control precision is improved, but the system complexity increases

Engineering Contradiction:
Improvecurrent control precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a feedback-based PWM control system where the actual current is detected and compared with the target current. The duty ratio is automatically adjusted based on this feedback to maintain precise current control despite power supply voltage fluctuations. This feedback mechanism achieves high measurement precision through a relatively simple additive structure that monitors and corrects current in real-time.

Inventive Principle:
Principle #23Feedback

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

The system provides precise and adaptive control of damping forces, enhancing vehicle stability and ride comfort by maintaining optimal current levels to solenoids, even under varying conditions such as power supply fluctuations and temperature changes.

Implementation Method 1

a solenoid configured to control a damping force of a suspension

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Implementation Method 2

a current detector configured to detect a current value of a first current supplied to the solenoid

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The suspension controller adjusts a duty ratio in a pulse width modulation (PWM) control to control current supplied to the solenoid

Methodology Applied
Scientific EffectPulse width modulation:

Data Source

PatentEP3225437B1Suspension controller and suspension apparatus
Publication Date: 2019.07.24 SHOWA CORP
  • EP3225437B1 patent drawingFigure 1
  • EP3225437B1 patent drawingFigure 2
  • EP3225437B1 patent drawingFigure 3A~3B

AI summary

A suspension controller includes a target current setting unit (631A) configured to set a target current value, a current limitation setting unit (632A) configured to set a current limitation value, a current detector (633A) configured to detect a current value of a first current supplied to a solenoid (51A) that is configured to control a damping force of a suspension, a duty ratio setting unit (634A) configured to set a duty ratio based on the target current value, based on the current limitation value, and based on the current value detected by the current detector; and a current outputting unit (635A) configured to supply the solenoid (51A) with a second current that corresponds to the duty ratio set by the duty ratio setting unit (634A) and to a power supply voltage. The current limitation setting unit (632A) is configured to change the current limitation value based on the duty ratio set by the duty ratio setting unit (634A).