A method of on-demand energy delivery to an active suspension system comprising an actuator body, hydraulic pump, electric motor, plurality of sensors, energy storage facility, and controller is provided. The method comprises disposing an active suspension system in a vehicle between a wheel mount and a vehicle body, detecting a wheel event requiring control of the active suspension; and sourcing energy from the energy storage facility and delivering it to the electric motor in response to the wheel event.

Active vehicle suspension system

A vehicle suspension system including: (a) a suspension spring interconnecting a vehicle body and a wheel; (b) an actuator having an electric motor, such that the actuator is capable of generating, based on a force of the electric motor, an actuator force forcing the body and the wheel toward and away from each other, and causing the generated actuator force to act as a damping force against displacement of the body and the wheel; and (c) a control device for controlling the actuator force generated by the actuator, by controlling operation of the electric motor. The control device is capable of establishing a constant-force generating state in which the actuator force is constantly generated as a constant actuator force by the actuator with supply of an electric power thereto from a battery as an electric power source of the electric motor such that the generated constant actuator force acts in a rebound direction or a bound direction. The control device controls the constant-force generating state, based on a charge state of the battery.

Vehicle suspension system

A wheel vibration information signal detected by an acceleration sensor (11) mounted on a wheel (1) or an in-tire gas pressure fluctuation information signal detected by a pressure sensor (31) mounted in a tire is subjected to frequency analysis by frequency analysis means (14 (34)), so as to detect the vibration spectrum or the pressure fluctuation spectrum band value. The vibration level of the detected band is compared to a vibration level correspondence table (15T) showing the relationship between the road surface friction coefficient μ stored in the vibration level storage means (15) and the vibration level. Alternatively, the detected pressure level is compared to a pressure fluctuation level correspondence table (35T) showing the relationship between the road surface friction coefficient μ stored in the pressure fluctuation level storage means (35) and the pressure fluctuation level. Thus, it is possible to accurately estimate the value of road surface friction coefficient μ, thereby improving the vehicle safety.

Method and apparatus for estimating road surface state and tire running state, ABS and vehicle control using the same

By passing the vertical acceleration through a phase adjusting filter and a gain adjusting filter, the phase of the vertical acceleration is advanced by 49 degrees so that the phase difference with respect to the actual relative velocity becomes 180 degrees in the neighborhood of the vehicle body resonance point, thereby making the phase of the vertical acceleration, in effect, coincident with the phase of the relative velocity In the neighborhood of the vehicle body resonance point (1 Hz), the gain of the estimated relative velocity takes a small value In frequency regions other than the neighborhood of the vehicle body resonance point, the gain of the estimated relative velocity is increased Consequently, the controlled variable in the neighborhood of the vehicle body resonance point increases, and the controlled variable in higher frequency regions decreases Damping force is adjusted in correspondence to the controlled variable Thus, it is possible to improve ride quality in the neighborhood of the vehicle body resonance point (1 Hz)

Suspension control system

A variable shock absorber assembly of the adaptive or semi-active type or an active actuator wherein the actuator, sensors, electronic controller and valving are integral to and integrated into one assembly and comprise one compact integral unit. Feedback control provides a signal proportional to and indicative of the actuator position and velocity. The compact system is temperature compensated by incorporating temperature sensors into the integrated assembly. The integrated system also provides diagnostics integral to the assembly and an LED mounted on the assembly for providing a visual indication of system condition.

Variable shock absorber with integrated controller, actuator and sensors

A suspension control system for automotive vehicles automatically adjusts the damping strength of variable shock absorbers or other dampers in accordance with road surface conditions as recognized by frequency analysis of a vehicle height or vibration sensor signal. The sensor signal reflects vertical displacement of the vehicle body from the road surface and includes high-frequency components due solely to displacement of the wheels or unsprung mass relative to the road surface and low-frequency components due to displacement of the vehicle body or sprung mass. The sensor signal is filtered into these separate frequency bands, the amplitude of each of which is compared to a corresponding reference level. The results of comparison give an indication of the degree and scale of irregularities in the road surface; specifically, a high-amplitude low-frequency component indicates larger-scale bumps and dips capable of bouncing the vehicle whereas a strong high-frequency component reflects a rough-textured road surface, such as gravel. The comparison information is sent to a suspension system controller which causes actuation of the shock absorbers to a stiffer mode of operation when the low-frequency sensor signal components are relatively strong.

Tohru Takahashi

Papers

Automotive suspension control system with road-condition-dependent damping characteristics