Integrated multiple actuator electro-hydraulic units
Integrated multiple actuator electro-hydraulic systems as well as their methods of use are described. Depending on the particular application, the integrated electro-hydraulic systems may exhibit different frequency responses and/or may be integrated into a single combined unit.
1. An active suspension unit of a motor vehicle, the active suspension unit comprising:
a first active suspension actuator with an internal volume and a first piston that is slidably received in the internal volume and travels along a first axis, wherein the first actuator is interposed between a vehicle body and a wheel assembly;
a second actuator with an internal volume containing hydraulic fluid and a piston with a second axis of travel, wherein a pressure of the hydraulic fluid induces a force on the piston along the second axis of travel, wherein the second actuator is interposed between the vehicle body and the wheel assembly;
a first pressure source with at least a first port that is in fluid communication with the internal volume of the first actuator; and
a second pressure source with at least a first port that is in fluid communication with the internal volume of the second actuator;
wherein the two actuators are controlled to cooperatively apply a net force on the vehicle body and the wheel assembly;
wherein the first pressure source is a first hydraulic pump that is reversible; and
wherein the first actuator has a faster response than the second actuator.
2. The active suspension unit of claim 1 , wherein the first axis and the second axis are operatively in parallel.
3. The active suspension unit of claim 1 , wherein the second pressure source is a second hydraulic pump.
4. The active suspension unit of claim 3 , wherein the first hydraulic pump and the second hydraulic pump are the same device.
5. The active suspension unit of claim 3 , wherein at least one of the first hydraulic pump and the second hydraulic pump is a hydraulic motor-pump.
6. An integrated motion control unit, comprising:
a first actuator that includes a housing with an internal volume separated into a compression volume and an extension volume by a double-acting piston and a piston rod attached to the piston;
a hydraulic pump that has a first port that is in fluid communication with the extension volume, and a second port that is in fluid communication with the compression volume; and
a second actuator that includes a first volume and a second volume and a double acting piston with a first surface acted on by the fluid in the first volume and a second surface acted on by the fluid in the second volume, wherein the first volume is in fluid communication with the first port of the hydraulic pump and the second volume is in fluid communication with the second port of the hydraulic pump;
wherein the first actuator and the second actuator are operatively in parallel to each other, and interposed between a first and a second structure, and wherein the first actuator has a faster response than the second actuator.
7. The integrated motion control unit of claim 6 , further comprising at least one low pass hydraulic filter located along a flow path between the hydraulic pump and the second actuator.
8. The integrated motion control unit of claim 7 , further comprising a spring that is operatively in parallel with the first actuator and operatively in series with the second actuator.
9. The integrated motion control unit of claim 7 , wherein the first actuator has a bandwidth extending to an upper limit of at least 10 Hz and the second actuator has a bandwidth extending to an upper limit of no more than 3 Hz.
10. The integrated motion control unit of claim 9 , wherein the first actuator has a bandwidth extending to an upper limit of at least 20 Hz and the second actuator has a bandwidth extending to an upper limit of no more than 3 Hz.
11. The integrated motion control unit of claim 7 , further comprising a third actuator that includes a first volume and a second volume and a double-acting piston with a first surface acted on by the fluid in the first volume and a second surface acted on by the fluid in the second volume, wherein the first volume is in fluid communication with the first port of the hydraulic pump and the second volume is in fluid communication with the second port of the hydraulic pump, and wherein the third actuator has a slower response than the second actuator.
12. The integrated motion control unit of claim 11 , wherein the third actuator has a bandwidth extending to an upper limit of no more than 0.5 Hz.
13. The integrated motion control unit of claim 6 , wherein the first structure is a vehicle body of a vehicle and the second structure is a wheel assembly of the vehicle.
14. The integrated motion control unit of claim 6 , wherein the first actuator has a bandwidth up to at least 20 Hz and the second actuator has a bandwidth up to no more than 3 Hz.
15. The integrated motion control unit of claim 6 , wherein the hydraulic pump is a hydraulic motor-pump.