Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

At least one controller configured to control an actuator of an active suspension system. The at least one controller includes circuitry configured to determine an actuator state, and apply the actuator state and a commanded state to an inverse model of the actuator to produce an actuator command. The circuitry is configured to produce the actuator command by a process that includes performing low pass filtering and phase compensation to correct a phase introduced by the low pass filtering.

A method for reshaping an electric drive signal of a real-time damper in a sprung mass system includes detecting a periodic frequency and magnitude of a target periodic vibration of a sprung mass. The periodic vibration has velocity and elasticity components that are 90 degrees out-of-phase. An electric drive signal to the real-time damper is reshaped by a controller depending on polarity of the velocity component to thereby generate a composite drive signal. The damper is energized using the composite drive signal to modify a damper force. Reshaping the electric drive signal includes injecting a force and/or an intermittent drive suppression component onto the electric drive signal based on the frequency and magnitude. The sprung mass system may have a frame and body, motion and wheel speed sensors, the real-time dampers, road wheels, and a controller programmed to perform the method.

A method for ascertaining the instantaneous roadway roughness in a vehicle. In the method, the frequency-dependent amplitude response is determined from the wheel speed, and a roughness characteristic variable is ascertained as a measure of the roadway roughness.

The present invention relates to a method for determining a functional status of a vehicle shock absorber arrangement (100). The method determines a difference between force values during compression and expansion of the vehicle shock absorber arrangement (100), whereby the shock absorber arrangement (100) can be determined to be degraded if the difference is below a predetermined threshold.

A method for adjusting the damper hardness of a vibration damper of a wheel of a transportation vehicle, wherein the transportation vehicle body movement signal is generated by a control device of the transportation vehicle from a first sensor signal of the first sensor unit connected fixedly in to a transportation vehicle body, a wheel movement signal is generated from a second sensor signal of a second sensor unit which detects a wheel position of the wheel with respect to the body, a speed signal which describes a speed of the transportation vehicle body is generated based on the transportation vehicle body movement signal, and the wheel movement signal and an actuation signal for setting the damper hardness is generated based on the speed signal. The transportation vehicle body movement signal is filtered by a first filter unit and/or the wheel movement signal is filtered by a second filter unit.

A control system (300) for controlling an active suspension system (104) of a vehicle (100), the active suspension system comprising suspension actuators (502), the control system comprising one or more controller (301), wherein the control system is configured to: in dependence on an activation signal (904), provide (908) a control signal to the active suspension system to cause the suspension actuators of the active suspension system to repetitively pulse vertical force through wheels (FR, FL, RR, RL) of the vehicle in a controlled pattern determined by the one or more controller, to vary wheel-to-surface contact patch forces, wherein the pattern comprises repetitively pulsing vertical force through at least one of the wheels at a first phase and through at least one other of the wheels at a second phase.

An axle/suspension system for a heavy-duty vehicle including a wheel and a sensor. The sensor is operatively connected to an air spring mounted on the axle/suspension system and is capable of detecting a condition of a road or the heavy-duty vehicle. The air spring has a stiffness capable of being altered in response to the sensor and to reduce resonant load variation on the wheel.

A motion sickness control system for a vehicle includes a vibrator. The motion sickness control system includes a sensor configured to measure vibration of the vehicle. The motion sickness control system includes a computer having a processor and a memory storing instructions executable by the processor to actuate the vibrator at a target frequency based on the measured vibration of the vehicle. The target frequency attenuates the measured vibration of the vehicle.

A vibration control element includes a nanovoided polymer layer having a first damping coefficient and a first resonance frequency in a first state and a second damping coefficient and a second resonance frequency in a second state, where the first damping coefficient is different from the second damping coefficient and the first resonance frequency is different from the second resonance frequency.