Supervision of several electro-hydraulic actuators operating on a common output

Claim 2

Apparatus for supervising an electro-hydraulic actuator system having a plurality of at least three individual pistoncylinder actuators, wherein the pistons are interconnected to operate on a common load, and each cylinder is pressurecontrolled by a separate electro-hydraulic controller comprising: comparator means connected to each of the cylinders of the plurality to compare the pressure in each of the cylinders of the plurality respectively with the pressure of at least two other cylinders of the plurality for obtaining a closed loop of comparisons, each resulting in an output and wherein at least two output signals indicate in each instance when operations oF a piston of a cylinder actuator differs from the operation of the pistons of the other piston-cylinder actuators of the plurality; and means connected to be responsive to the outut signals for obtaining control of the respective actuator to balance the operation of the respective cylinder or to shut it down in dependence upon the magnitude of the difference in operation as indicated by the output signals of the comparator means.

Claim 3

Apparatus as in claim 1 for more than three actuators wherein the comparator means provide for comparison of each actuator with all other actuators of the plurality.

Claim 4

Apparatus as in claim 1, wherein the comparator means includes a plurality of hydraulic comparators, each comparator having two chambers respectively connected to one side and the other side of a piston therein and connected to two piston chambers respectively of two actuators of the plurality which are being compared in that the respective pistons of the actuators reduce or increase the pressure in the chambers in unison when operated.

Claim 5

Apparatus as in claim 1, wherein the comparator means includes a plurality of double cylinder-double piston units and being connected to duplicate the pressure on the pistons of two actuators and providing a differential displacement.

Claim 6

Apparatus as in claim 1, wherein the comparator means includes individual pressure probes for the actuator cylinders, providing electrical outputs indicative of the operational state of the cylinders; and circuit means for providing for the comparison of each said electrical output as indicative of the operational state of the respectively associated cylinder of the plurality, with the outputs of two other ones of the pressure probes.

Claim 7

Apparatus for supervising a plurality of electro-hydraulic actuators operating on a common output, each actuator having a piston chamber and a piston dividing the piston chamber into a first and second chamber, the first chamber of all piston chambers increasing upon advance of the common output, the actuators of the plurality being connected for control by a common input, comprising: a plurality of electro-hydraulic comparators each including a differential piston, and connected to the actuators wherein the connection includes a differential connection of one of the plurality of comparators between the first chambers of two actuators, a second one of the plurality of comparators being connected differentially between the second chamber of one of the two actuators and the second chamber of a third one of the actuators, a third one of the plurality of comparators being connected between the first chamber of the third one and of another one of the actuators, and wherein a last one of the plurality of actuators has its second chamber connected to the second chamber of the first one of the actuators via a last one of the differential comparators so as to establish a closed loop as between all comparators and all actuators of the respective pluralities; first electrical circuit means connected to the comparators and being adjusted by the respective differentially operated pistons for producing electrical output signals respectively indicative of the disposition of the differentially operated pistons of the comparators; second electrical circuit means connected to the first circuit means, to be responsive to the outputs in pairs as derived from the comparators connected to the same actuator for establishing an electrical criterium for each of the actuators, whether or not the respective actuator is operated; and third circuit means connected to the second circuit means and controlling the actuators individually in dependence upon the established criterium for balancing operation of all actuators of the plurality.

Claim 8

Apparatus for supervising a plurality of electro-hydraulic actuators operating on a common output, each actuator having a piston chamber and a piston dividing the piston chamber into a first and second chamber, the first chamber of all piston chambers increasing upon advance of the common output, the actuators of the plurality being connected for control by a common input, comprising: a plurality of electro-hydraulic comparators each including a differential piston, and connected to the actuators wherein the connection includes a differential connection of one of the plurality of comparators between the first chambers of two actuators, a second one of the plurality of comparators being connected differentially between the second chamber of one of the two actuators and the second chamber of a third one of the actuators, a third one of the plurality of comparators being connected between the first chamber of the third one and of another one of the actuators, and wherein a last one of the plurality of actuators has its second chamber connected to the second chamber of the first one of the actuators via a last one of the differential comparators so as to establish a closed loop as between all comparators and all actuators of the respective pluralities; first electrical circuit means connected to the comparators and being adjusted by the respective differentially operated pistons for producing electrical output signals respectively indicative of the disposition of the differentially operated pistons of the comparators; second electrical circuit means connected to the first circuit means, to be responsive to the outputs in pairs as derived from the comparators connected to the same actuator for establishing an electrical criterium for each of the actuators, whether or not the respective actuator is operated; and third circuit means connected to the second circuit means and controlling the actuators individually in dependence upon the established criterium for balancing operation of all actuators of the plurality.

Claim 9

Apparatus as in claim 6, wherein the first circuit means includes an adjustable circuit element for each of the comparators; the second circuit means including circuitry respectively connected to the adjustable circuiT elements for two comparators being connected to the same actuator of the plurality; the third circuit means including a summing amplifier receiving the command signal, a feed-back signal indicative of the disposition of the actuator and a signal from the circuitry for providing corrective control.

Claim 10

Apparatus for supervising a plurality of electro-hydraulic actuators operating on a common output, each actuator having a piston chamber and a piston dividing the piston chamber into a first and a second chamber, the first chamber of all piston chambers increasing upon advance of the common output, the actuators of the plurality being connected for control by a common input, comprising: a plurality of electro-hydraulic comparators, each having a pair of pistons on a common piston rod, each piston disposed in differential chambers, the comparators connected with one of the differential chambers of the first and second chamber of one of the actuators, and with the respective other differential chambers of the first and second chambers of another one of the actuators, so that the comparators interconnect the actuators for establishing a closed sensing loop in which each actuator is connected to two comparators; a plurality of adjustable circuit elements respectively connected to and operated by the piston rods of the comparators; circuit means connected to the adjustable circuit elements to be responsive to the adjustments thereof and providing output signals, respectively representing the adjustment of two adjustable elements connected to two comparators, which are connected to the same actuator of the plurality; and means for controlling the actuators respectively in response to said output signals.

Claim 11

Apparatus for supervising a plurality of electro-hydraulic actuators operating on a common output, each actuator having a piston chamber and a piston dividing the piston chamber into a first and a second chamber, the first chamber of all piston chambers increasing upon advance of the common output, the actuators of the plurality being connected for control by a common input, comprising: a plurality of electro-hydraulic comparators, each having a pair of pistons on a common piston rod, each piston disposed in differential chambers, the comparators connected with one of the differential chambers of the first and second chamber of one of the actuators, and with the respective other differential chambers of the first and second chambers of another one of the actuators, so that the comparators interconnect the actuators for establishing a closed sensing loop in which each actuator is connected to two comparators; a plurality of adjustable circuit elements respectively connected to and operated by the piston rods of the comparators; circuit means connected to the adjustable circuit elements to be responsive to the adjustments thereof and providing output signals, respectively representing the adjustment of two adjustable elements connected to two comparators, which are connected to the same actuator of the plurality; and means for controlling the actuators respectively in response to said output signals.

Claim 12

Apparatus as in claim 8, including additional circuitry for controlling shut down of an actuator of the plurality on response to output signals indicative of faulty actuator operation.

Claim 13

Apparatus as in claim 9, including a plurality of additional, similarly constructed comparators, so that together with the first mentioned plurality of comparators each actuator is connected to all other actuators via one of the comparators of the pluralities.

Claim 14

Apparatus for supervising a plurality of electro-hydraulic actuators, each having a piston and cylinder, the pistons of the several actuators being interconnected to provide for a common displacement output, the combination comprising: a plurality of comparators, each connected to compare the hydraulic pressure state of a cylinder of one actuator with the hydraulic pressure state of a cylinder of another actuator, whereby each actuator of the plurality is connected to two different comparators of the plurality to obtain a closed comparison loop, each comparator providing an electrical output; circuit means respectively connected for combining the outputs of the two comparators connected to the same actuator to obtain an electrical signal indication of the operational condition of the actuator; means responsive to the electrical signal indication when indicating a relatively small error for controlling the respective actuator; and means responsive to the electrical signal indication when indicating a relatively large error to turn the actuator off.

Claim 15

Apparatus for supervising a plurality of electro-hydraulic actuators, each having a piston and cylinder, the pistons of the several actuators being interconnected to provide for a common displacement output, the combination comprising: a plurality of comparators, each connected to compare the hydraulic pressure state of a cylinder of one actuator with the hydraulic pressure state of a cylinder of another actuator, whereby each actuator of the plurality is connected to two different comparators of the plurality to obtain a closed comparison loop, each comparator providing an electrical output; circuit means respectively connected for combining the outputs of the two comparators connected to the same actuator to obtain an electrical signal indication of the operational condition of the actuator; means responsive to the electrical signal indication when indicating a relatively small error for controlling the respective actuator; and means responsive to the electrical signal indication when indicating a relatively large error to turn the actuator off.

Claim 16

Apparatus as in claim 11, wherein the comparators each include a differential piston arrangement operatively connected to the respective two comparator cylinders; and an adjustable circuit element operated by the differential piston to provide an electrical output indicative of the comparator output.

Claim 17

Apparatus as in claim 12, wherein each comparator has two serially connected differential pistons, each of the latter pistons being respectively operated from both sides of the actuator piston in the respective actuator cylinder.

Claim 18

Apparatus as in claim 12, wherein each comparator as connected to the respective two actuator cylinders is connected to comparable sides of the respective pistons therein.

Claim 19

ApparatuS as in claim 11, wherein the comparators each include two pressure sensing devices, respectively connected to the actuator cylinders and providing an electrical output, and circuit means combining the outputs of the pressure sensing device to obtain the respective comparator output.

Claim 20

Apparatus as in claim 15, wherein the comparators connected to the same actuator of the plurality share the respective pressure sensing device.