An "active" suspension system provides two parallel force-transmitting paths between the body and wheel of a vehicle. The first path has a main spring (41), and the second path includes an actuator (42) and a spring (43). LVDT's (53,55) are arranged to monitor the displacements of the actuator (42) and the spring (43). The actuator is arranged in a high-gain closed position or velocity servoloop. The actual force (F.sub.w) exerted by the suspension system on the body is determined and compared with a desired force (F.sub.c) to produce a force error signal (F.sub.e). The force error signal (F.sub.e) is converted to a command signal supplied to the servoloop. The servoloop operates the actuator (42) so as to continuously drive the force error signal (F.sub.e) toward zero.
An active system for isolating vibrations includes: at least one first vibratio-isolating device, arranged between a load and a sstanding surface, for at least partially decoupling the static and dynamic forces acting between the load and the standing surface, the first vibration-isolating device includes a passively isolating coupling element for mechanically decoupling the static and dynamic forces including a natural frequency; at least one second vibration-isolating device, assigned to the load, for imparting control forces to the load for actively damping the substantially decoupled dynamic forces, the second fibratio-isolating device including a coupling element for dynamically coupling said second vibration-isolating device to the load and the first isolating device<the coupling element including a natural frequency; means for tuning the control forces of the second vibratio-isolating device and the natural frequencies, wherein the control forces of the second vibration-isolating device and the natural frequencies are determined by means of characteristic curves describing the functional dependency of the control forces to the natural frequencies of the passively isolating doupling element and the ratio of the natural frequencies.
A suspension system for motor vehicles is disposed between body (1) and wheel (2) and is provided with a damper (4) with integrated resonance dampers (40, 48) for improved insulation of transmission of road unevenness to the body. The resonance damper is formed in that the casing (40) of the damper (4) forms a moving mass m.sub.40 between the body (1) and the wheel (2), the casing being connected to the wheel via a spring (48) harmonized with the mass m.sub.40. The pistons (41, 42) of the damper are connected via piston rods (43, 44, respectively) to the body (1) and the wheel (2), respectively. By a fixed adaptively regulated flow between the chambers (5--7) formed in the damper (4) in response to parameters dependent upon the oscillation cycle, there will be obtained improved insulation primarily in those resonance ranges which are typical for suspension systems for motor vehicles,
An active suspension system for an automotive vehicle includes a mono-tube shock absorber for passively absorbing impact from a wheel, an actuator formed around the mono-tube shock absorber, the actuator acting as a cylinder for a mono-tube shock absorber, a coil spring mounted around the actuator for assisting the mono-tube shock absorber and suspending a vehicle body, a servo amplifier connected to the actuator for adjusting hydraulic pressure, a servo valve connected to the servo amplifier for duty control by selectively activating the actuator, and a on/off valve electrically connected to the servo valve for selectively activating the actuator.
An elevator hoistway rail profile is made by summing a doubly integrated car horizontal acceleration signal with a relative rail-car displacement signal and storing the summed signal according to the vertical position of the car in the hoistway.
A method and apparatus for actively counteracting a disturbing force acting on a suspended elevator cab in a frame moving vertically in a hoistway is disclosed. A manifestation of the disturbing force such as acceleration is sensed and counteracted, for example, by effectively adding mass to the cab in proportion to the sensed acceleration. This may be accomplished by using an electromagnet actuator for actuating the suspended cab in response to a control signal from a control means which is in turn responsive to the sensed signal. Whatever type of actuator is used, it may be used as well to bring the suspended cab to rest with respect to a hoistway sill prior to transferring passengers. The control means may be analog or digital or a combination of both. A preferred analog-digital approach is disclosed in which the digital part is responsive to accelerometer signals, the analog part is responsive to a force command signal from the digital part and provides a position feedback signal in return. In a preferred embodiment, four electromagnet actuators are situated in the corners of the cab between the floor of the frame and the bottom of the suspended cab. Each actuator may act along a line which intersects the walls of the cab at a forty-five degree angle. A single axis embodiment is also disclosed.
