Suspension Device Steering Initial Stage Damping Control
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Solution Overview
Problem
Existing suspension devices struggle to sufficiently suppress vehicle body roll at the initial stage of steering, leading to poor ride quality due to delayed damping force generation and reliance on roll rate, which becomes minimal when the vehicle is straight, resulting in inadequate lateral movement control.
Innovation Solution
A suspension device with a damper, damping force adjustment mechanism, control device, lateral acceleration detection unit, roll angular velocity detection unit, and steering angular velocity detection unit, which calculates a maximum damping force based on steering, lateral, and roll angular velocities to generate an additional damping force at the initial stage of steering, ensuring timely and effective roll suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If damping forces are generated based on roll rate, then the system responds to vehicle body roll, but the roll rate is very small at the initial stage of steering, making it difficult to suppress roll effectively
Solution Approach 1:
The control device calculates a steering initial stage additional damping force based on steering angular velocity before the roll rate becomes significant. This preliminary action compensates for the delayed roll response, ensuring damping forces are generated timely to suppress roll at the initial stage of steering.
Solution Approach 2:
The system dynamically switches between different control modes: using steering angular velocity for additional damping force calculation during the initial steering stage (when steering angular velocity exceeds dead band), and relying on roll rate for normal operation. This dynamic adaptation resolves the contradiction by adjusting the control strategy according to the steering phase.
2Reliability
If the proportional gain is increased based on steering speed, then roll during steering can be suppressed, but the roll rate becomes almost 0 when running straight, causing damping force to become lowest and lateral swinging movements to persist
Solution Approach 1:
The control device dynamically adjusts the damping force calculation mode based on steering conditions. When steering angular velocity exceeds the dead band, it calculates additional damping force from steering angular velocity. When running straight (steering angular velocity within dead band), it relies on roll rate and lateral acceleration, ensuring stable damping force generation in both scenarios.
Solution Approach 2:
The system changes the control parameters based on operating conditions: using steering angular velocity as the basis for additional damping force during steering, and switching to roll rate and lateral acceleration when running straight. This parameter adaptation resolves the contradiction by optimizing the control strategy for each operational phase.
3Device complexity
If damping force is calculated only from roll rate, then the system structure remains simple, but the damping force becomes insufficient when roll rate is minimal, deteriorating ride quality
Solution Approach 1:
The control device calculates a steering initial stage additional damping force based on steering angular velocity and lateral acceleration before the roll rate becomes significant. This preliminary calculation ensures sufficient damping force is available early in the steering maneuver, improving reliability without requiring complex additional hardware.
Solution Approach 2:
The control device uses feedback from steering angular velocity sensors to determine when to apply the steering initial stage additional damping force. This feedback mechanism allows the system to automatically adjust damping forces based on steering conditions, improving reliability while maintaining relatively simple system structure.
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 suspension device effectively suppresses vehicle body roll and improves ride quality by generating increased damping forces in response to steering speed, preventing lateral swinging and maintaining ride quality even when the vehicle is straight.
Implementation Method 1
a damper interposed between a vehicle body and a wheel in a vehicle and adapted to exert a damping force for suppressing relative movements of the vehicle body and the wheel in a vertical direction
Implementation Method 2
the control device sets a maximum damping force out of a damping force calculated from the steering angular velocity, a damping force calculated from the acceleration in the lateral direction and a damping force calculated from the roll angular velocity as a steering initial stage additional damping force
Data Source
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AI summary
A suspension device includes damper interposed between vehicle body and wheel in vehicle and exerted damping force for suppressing vertical movements of vehicle body and wheel, damping force adjustment mechanism adjusts damping force, control device controls damping force adjustment mechanism, lateral acceleration detection unit detects an lateral acceleration acting on vehicle body, roll angular velocity detection unit detects roll angular velocity of vehicle body, and steering angular velocity detection unit detects steering angular velocity of steering wheel. The control device sets maximum damping force out of damping force calculated from steering angular velocity, damping force calculated from lateral acceleration and damping force calculated from roll angular velocity as steering initial stage additional damping force, calculates final damping force of damper using steering initial stage additional damping force and performs steering initial stage control of controlling damper when steering angular velocity exceeds predetermined dead band.