INDEPENDENT AND CROSS-LINKED HYDRAULIC ACTUATOR SYSTEMS
Apparatus and methods are described where multiple linear and/or rotary actuators operate cooperatively in, for example, cross-linked arrangements to control the motion of sprung and unsprung masses in a vehicle. The actuators may include linear primary suspension actuators, spring perch actuators and/or rotary roll-bar actuators that, in some operating modes, are driven directly or indirectly by one or more hydraulic machines.
1 . A suspension system for a vehicle, comprising:
a first linear actuator interposed between a sprung mass of the vehicle and an unsprung mass of the vehicle; and
a first rotary actuator;
wherein the first linear actuator and the first rotary actuator are configured and positioned to cooperatively apply a roll moment on a vehicle body of the vehicle.
2 . The system of claim 1 , wherein the sprung mass is a vehicle body.
3 . The system of claim 2 , wherein the first linear actuator is a hydraulic actuator that includes a first compression volume and a first extension volume.
4 . The system of claim 3 , wherein the first rotary actuator is a rotary hydraulic actuator capable of applying a moment to a first roll bar of the vehicle.
5 . The system of claim 4 , further comprising a first hydraulic device, selected from the group consisting of a pump and a hydraulic motor, configured and positioned to apply a first differential pressure between the first compression volume and the first extension volume, and to apply the first differential pressure between a first chamber and a second chamber of the first rotary actuator.
6 . The system of claim 5 , further comprising a second linear actuator that is a hydraulic actuator that includes a second compression volume and a second extension volume.
7 . The system of claim 6 , wherein a second hydraulic device is configured and positioned to apply a second differential pressure between the second compression volume and the second extension volume, and to apply the second differential pressure between a third chamber and a fourth chamber of the first rotary actuator.
8 . The system of claim 7 , wherein the first roll bar is one of a front roll bar of the vehicle or a rear roll bar of the vehicle.
9 . The system of claim 5 , further comprising a pressure intensifier, wherein the first hydraulic device is configured and positioned to apply a first differential pressure between the first compression volume and the first extension volume, and to apply the first differential pressure between a first chamber and a second chamber of the pressure intensifier, and wherein a pressure differential produced by the pressure intensifier is applied between a first chamber and a second chamber of the first rotary actuator.
10 . An active suspension system comprising:
a first hydraulic actuator assembly that includes a first primary hydraulic actuator directly driven by a first hydraulic device, wherein the first primary hydraulic actuator includes a first compression volume and a first extension volume;
a second hydraulic actuator assembly that includes a second primary hydraulic actuator directly driven by a second hydraulic device, wherein the second primary hydraulic actuator includes a second compression volume and a second extension volume;
a rotary hydraulic roll bar actuator operatively coupled to a roll bar and configured to be driven by a combination of the first and second hydraulic devices;
wherein, in at least one mode of operation, the first primary hydraulic actuator, the second primary hydraulic actuator and the rotary hydraulic roll bar actuator are configured and positioned to cooperatively apply a roll moment to a vehicle body.
11 . The system of claim 10 , wherein the rotary hydraulic roll bar actuator includes a first chamber that is in fluid communication with the first compression volume, a second chamber that is in fluid communication with the first extension volume, a third chamber that is in fluid communication with the second compression volume, and a fourth chamber that is in fluid communication with the second extension volume and wherein in at least one mode of operation the first hydraulic device produces a pressure differential between the first and the second chambers that induces a first roll moment in the roll bar and the second hydraulic device produces a pressure differential between the third and the fourth chambers that induces a second roll moment in the roll bar.
12 . The system of claim 11 , wherein the first and second roll moments are in the same direction.
13 . A method of controlling a suspension system of a vehicle, the method comprising:
actuating a first linear actuator interposed between a sprung mass of the vehicle and an unsprung mass of the vehicle; and
actuating a rotary actuator; and
cooperatively applying, by the first linear actuator and the rotary actuator, a roll moment to a vehicle body of the vehicle.
14 . The method of claim 13 , wherein the sprung mass is a vehicle body, and wherein the first linear actuator is a linear hydraulic actuator.
15 . The method of claim 14 , wherein the rotary actuator is a rotary hydraulic actuator.
16 . The method of claim 15 , wherein actuating the first linear actuator comprises operating a first hydraulic device, selected from the group consisting of a pump and a hydraulic motor, to establish a first differential pressure between a first compression volume and a first extension volume of the first linear actuator.
17 . The method of claim 16 , wherein actuating the rotary actuator comprises operating the first hydraulic device to establish the first differential pressure between a first chamber and a second chamber of the rotary hydraulic actuator operatively coupled to a first roll bar of the vehicle.
18 . The method of claim 17 , further comprising actuating a second linear actuator that includes a second compression volume and a second extension volume.
19 . The method of claim 18 , further comprising operating a second hydraulic device to apply a second differential pressure between the second compression volume and the second extension volume, and applying the second differential pressure to a third chamber and a fourth chamber of the rotary actuator.
20 . The method of claim 19 , wherein the first linear actuator, the second linear actuator, and the rotary actuator cooperatively apply a roll moment to the body of the vehicle.
21 . The method of claim 16 , further comprising directing the first differential pressure to a pressure intensifier, and applying, by the pressure intensifier, a second differential pressure to a first chamber and a second chamber of the rotary actuator, wherein the second differential pressure is higher than the first differential pressure.