Vehicle Suspension Control Using Calculated Acceleration
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Solution Overview
Problem
Existing suspension controlling apparatuses for vehicles react too sensitively to acceleration sensor detection values, leading to difficulty in controlling damping force with a desired amount, resulting in delayed vehicle body behavior responses.
Innovation Solution
A suspension controlling apparatus with a control unit that calculates acceleration based on operation input and target damping force, using a damping force map and differentiation values, and includes features like traveling resistance calculation, engine speed, and brake operation detection to accurately control damping force, eliminating the need for direct acceleration sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suspension controlling apparatus reacts highly sensitively to the acceleration sensor detection value, then the responsibility to vehicle body behavior is enhanced, but it becomes difficult to control the damping force with a desired controlling amount
Solution Approach 1:
The patent introduces an intermediary calculation process that computes acceleration from operation input amount and traveling resistance rather than directly using acceleration sensor values. This intermediary calculation acts as a mediator between the raw sensor data and the damping force control, filtering out excessive sensitivity while maintaining responsiveness to actual vehicle dynamics.
Solution Approach 2:
The patent changes the parameter used for control from direct acceleration sensor values to calculated acceleration values derived from operation input amount and traveling resistance. This parameter transformation allows for smoother control characteristics while maintaining the desired responsiveness to vehicle body behavior.
2Ease of operation
If a filter process is carried out for the acceleration sensor detection value, then the suspension controlling apparatus does not react highly sensitively, but delay occurs with respect to the behavior of the vehicle body
Solution Approach 1:
The patent replaces the mechanical filter process with a calculation-based approach. Instead of filtering acceleration sensor values, the system calculates acceleration from operation input amount and traveling resistance, eliminating the time delay associated with filter processes while still achieving smooth control characteristics.
Solution Approach 2:
The calculation of acceleration from operation input and traveling resistance serves as an intermediary that naturally smooths the control signal without introducing delay. This intermediary approach provides both smoothness and responsiveness simultaneously, resolving the contradiction between filtering and real-time response.
3Ease of operation
If acceleration is calculated based on operation input amount and traveling resistance, then the damping force can be controlled with desired controlling amount, but the device complexity increases
Solution Approach 1:
The control unit performs multiple functions including detecting operation input amount, calculating traveling resistance from vehicle speed, and computing acceleration. By making the control unit multi-functional, the patent avoids adding separate dedicated devices for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent merges the acceleration calculation function with the existing control unit that already handles damping force control. By combining multiple functions in a single control unit, the system achieves the desired controllability without significantly increasing overall device complexity.
Data Source
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AI summary
To make it possible, in a suspension controlling apparatus for a vehicle which includes a suspension whose damping force is variably settable and a control unit capable of controlling the damping force of the suspension on the basis of a target damping force, to control the damping force of the suspension with a desired control amount and a high responsibility. [Solving Means] A control unit 28 includes acceleration calculation means 45A for calculating an acceleration in a forward and rearward direction of a vehicle on the basis of an operation input amount to the vehicle and target damping force setting means 47 for determining a target value of damping force on the basis of a damping force map determined in advance in response to the acceleration and a differentiation value of the acceleration.