ADAPTIVE VARIABLE SUSPENSION SYSTEM


  1. OUTLINE


    1. An Adaptive Variable Suspension System (AVS) is used.

    2. The AVS controls the damping force of the shock absorbers for all 4 wheels in accordance with the driving conditions and road surface conditions. In this way, it achieves a comfortable ride, excellent driveability and high levels of stability.

    3. The AVS is a semi-active type of suspension. Its suspension control ECU estimates the vehicle conditions based on the signals from the sensors and the switch. Then, the suspension control ECU actuates the absorber control actuator, varies the flow of the oil and controls the damping force. This achieves pinpoint control due to superior response performance.

    4. By operating the absorber control switch*1 or drive mode select*2, the driver can select 3 types of damping forces for the shock absorbers.


      • *1: Models without drive mode select

      • *2: Models with drive mode select

    5. Non-linear H∞ control is used for the basic control of the damping force.

      Tech Tips


      • H∞ control is a theory for designing a controller that meets the control specifications that are represented by the H∞ norm (a measurement unit of the transfer function in the system). When this is expanded into a non-linear system, it is called "non-linear H∞ control".

      • The "H" is the initial letter of the mathematician named Hardy (who studied the stability of control systems) who advocated the mathematical space that is handled by this control logic. The "∞" represents the ∞ norm, which is one of the mathematical units used for measuring the size of the signals.

  2. MAIN FEATURES


    1. Riding Comfort


      1. As vibrations in the roll direction can cause discomfort, repercussion control (nonlinear H∞ control) has been provided as a result of a focus on body control in the roll direction.

      2. Under repercussion control, the 4 wheels work simultaneously to suppress vibrations in the heave, roll and pitch directions. As a result, vibration suppression in the roll and pitch directions is ensured while conventional vibration suppression in the heave direction is maintained.

        Figure 1. Repercussion Control (New)

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        *1 Heave Direction
        *2 Roll Direction
        *3 Pitch Direction

        Figure 2. Repercussion Control (Previous)

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        *1 Heave Direction