Electro-hydraulic robot positioning system

Claim 2

Electro-hydraulic control system for robot devices of the type having work actuating means comprising a closed-loop hydraulic circuit having a liquid delivery side and a liquid return side, means for pumping hydraulic liquid into the delivery side of said circuit while simultaneously receiving hydraulic liquid from the return side thereof, and a plurality of hydraulic actuators operatively connected to the delivery and return sides of said hydraulic circuit through individually controlled valve means and adapted to be connected to said work actuating means to actuate the same, said valve means being independently operable to move said work actuating means selectively in either of two directions or to hold said work actuating means stationary.

Claim 3

In an electro-hydraulic control system for robot devices of the type having work actuating means, the improvement comprising a self-contained, closed-loop hydraulic circuit having a pair of separate conduit means through which hydraulic liquid flows in the circuit and including a plurality of hydraulic motor means each having a cylinder and a movable actuator in said cylinder dividing the latter into separate chambers, said conduit means being connected to respective chambers of said hydraulic motor means and permitting flow of hydraulic liquid between said hydraulic motor means, at least one of said hydraulic motor means comprising drive motor means and said drive motor means being operative to pump hydraulic liquid at relatively high pressure alternately into said conduit means, other of said hydraulic motor means comprising driven motor means operative by the pressure of liquid from said drive motor means to manipulate the work actuating means of said robot device, main valve means connected to said conduit means between said drive motor means and said driven motor means operable to direct hydraulic liquid from said drive motor means always to one of said conduit means for delivery to said driven motor means, whereby the other of said conduit means between said main valve means and said driven motor means returns hydraulic liquid to said drive motor means, control valve means connected to said conduit means between said main valve means and said driven motor means for controlling the flow of hydraulic liquid to and from said driven motor means, and accumulator means connected to said return conduit means between said main valve means and said driven motor means for maintaining a predetermined minimum pressure in said hydraulic circuit and operative to accommodate variations in the amount of hydraulic liquid in the delivery and return sides of said hydraulic circuit due to operation of said hydraulic motor means.

Claim 4

In an electro-hydraulic control system for robot devices of the type having work actuating means, the improvement comprising a self-contained, closed-loop hydraulic circuit having a pair of separate conduit means through which hydraulic liquid flows in the circuit and including a plurality of hydraulic motor means each having a cylinder and a movable actuator in said cylinder dividing the latter into separate chambers, said conduit means being connected to respective chambers of said hydraulic motor means and permitting flow of hydraulic liquid between said hydraulic motor means, at least one of said hydraulic motor means comprising drive motor means and said drive motor means being operative to pump hydraulic liquid at relatively high pressure alternately into said conduit means, other of said hydraulic motor means comprising driven motor means operative by the pressure of liquid from said drive motor means to manipulate the work actuating means of said robot device, main valve means connected to said conduit means between said drive motor means and said driven motor means operable to direct hydraulic liquid from said drive motor means always to one of said conduit means for delivery to said driven motor means, whereby the other of said conduit means between said main valve means and said driven motor means returns hydraulic liquid to said drive motor means, control valve means connected to said conduit means between said main valve means and said driven motor means for controlling the flow of hydraulic liquid to and from said driven motor means, and accumulator means connected to said return conduit means between said main valve means and said driven motor means for maintaining a predetermined minimum pressure in said hydraulic circuit and operative to accommodate variations in the amount of hydraulic liquid in the delivery and return sides of said hydraulic circuit due to operation of said hydraulic motor means.

Claim 5

The invention as defined by claim 2 including actuator means, and speed reducer means driven by said actuator means, and wherein said drive motor means comprises a cylinder and a piston mounted for reciprocation in said cylinder, said piston having rods extending through both ends of said cylinder connected to and actuated by said speed reducer means.

Claim 6

The invention of claim 2 including a direct current servomotor having a drive shaft operatively connected to said drive motor means.

Claim 7

The invention of claim 2 wherein the actuator of said drive motor means is in the form of a reciprocable piston, and including a reversible, direct current servomotor having a rotatable drive shaft, and speed reducing means having a driven connection with the shaft of said servomotor and a driving connection with the piston of said drive motor means, said speed reducing means being operable to translate rotary motion from said servomotor to reciprocatory travel of said piston.

Claim 8

The invention of claim 2 wherein the actuator of said drive motor means is in the form of a reciprocable piston, and including a reversible, direct current servomotor having a rotatable drive shaft, and speed reducing means having a drive screw connected to the drive shaft of said servomotor, and a carriageconnected to the piston of said drive motor means including nut means on and movable linearly along said drive screw.

Claim 9

The invention of claim 2 wherein the actuator of said drive motor means is in the form of a reciprocable piston, and including a reversible, direct current servomotor having a rotatable drive shaft, and means operable by said servomotor for translating rotary motion of said servomotor drive shaft into reciprocatory motion of said drive motor means.

Claim 10

The invention as defined in claim 2 wherein said hydraulic circuit is provided with a plurality of said driven motor means each having a cylinder and a movable actuator in said cylinder, and wherein said delivery conduit means is connected to the cylinder of each driven motor means at one side of the actuator in said cylinder and said return conduit means is connected to the cylinder of each driven motor means at the other side of the actuator in said cylinder.

Claim 11

The invention as defined by claim 8 including a plurality of said control valve means, one for each of said driven motor means, each of said control valve means being operatively connected to a respective one of said driven motor means and operable individually to connect said delivery conduit means selectively to the cylinder of its respective driven motor means at either side of the actuator in said cylinder or to block the flow of hydraulic liquid completely to said cylinder, whereby said driven motor means can be selectively actuated individually and successively in predetermined sequence.

Claim 12

An electro-hydraulic control for a robot device of the type having a movable work actuating member comprising at least one hydraulic actuator means having individual chambers separated by a movable actuator element, said actuator element adapted to be connected to said work actuating member to operate the latter in use, a reversible, direct current servomotor, a stationary cylinder normally filled with hydraulic liquid, a double rod piston mounted for reciprocation in said cylinder, means driven by said servomotor operatively connected to said piston to slidably actuate the latter in one direction or the other in said cylinder depending on the direction of rotation of said motor, and a closed loop hydraulic system having delivery and return sides connected to said stationary cylinder at opposite sides of said piston and to respective chambers of said hydraulic actuator means at opposite sides of said movable actuator element.

Claim 13

An electro-hydraulic control for a robot device of the type having a movable work actuating member comprising at least one hydraulic actuator means having individual chambers separated by a movable actuator element, said actuator element adapted to be connected to said work actuating member to operate the latter in use, a reversible, direct current servomotor, a stationary cylinder normally filled with hydraulic liquid, a double rod piston mounted for reciprocation in said cylinder, means driven by said servomotor operatively connected to said piston to slidably actuate the latter in one direction or the other in said cylinder depending on the direction of rotation of said motor, and a closed loop hydraulic system having delivery and return sides connected to said stationary cylinder at opposite sides of said piston and to respective chambers of said hydraulic actuator means at opposite sides of said movable actuator element.

Claim 14

The invention as defined in claim 10 including flow diverter valve means connected to the delivery and return sides of said hydraulic system operative to establish communication between said stationary cylinder at either side of said double rod piston and the chambers of said hydraulic actuator means.

Claim 15

1 2. The invention as defined by claim 10 including piston-type accumulator means connected to the return side of said hydraulic system for assuring a relatively constant pressure in said hydraulic system and for accommodating variations in volume of hydraulic liquid in said system due to actuation of said movable actuator element.

Claim 16

An electro-hydraulic control for a robot device of the type having a movable work actuating means comprising a plurality of hydraulic actuators individually operable to impart different predetermined motions to said work actuating means, each of said hydraulic actuators having pressure chambers separated by a movable actuator element adapted to be operatively associated with and connected to said work actuating means, a reversible electric drive motor, a power cylinder normally filled with hydraulic liquid, a piston mounted for reciprocation in said cylinder defining individual pressure chambers at opposite sides thereof, connecting means driven by said motor operatively connected to said piston to slidably actuate the latter in one direction or the other depending on the direction of rotation of said motor, and a closed loop hydraulic system normally filled with hydraulic liquid and through which hydraulic liquid passes between said power cylinder and said hydraulic actuators, said hydraulic system having delivery and return sides connected to the pressure chambers of said power cylinder and to the individual pressure chambers of said hydraulic actuators, and valve means for connecting the pressure chamber into which said piston is moving always to the delivery side of said hydraulic system and for blocking flow of hydraulic liquid to said hydraulic actuators or for connecting the delivery side of said system selectively to the pressure chamber at one side or the other of the movable actuator element of each hydraulic actuator.

Claim 17

An electro-hydraulic control for a robot device of the type having a movable work actuating means comprising a plurality of hydraulic actuators individually operable to impart different predetermined motions to said work actuating means, each of said hydraulic actuators having pressure chambers separated by a movable actuator element adapted to be operatively associated with and connected to said work actuating means, a reversible electric drive motor, a power cylinder normally filled with hydraulic liquid, a piston mounted for reciprocation in said cylinder defining individual pressure chambers at opposite sides thereof, connecting means driven by said motor operatively connected to said piston to slidably actuate the latter in one direction or the other depending on the direction of rotation of said motor, and a closed loop hydraulic system normally filled with hydraulic liquid and through which hydraulic liquid passes between said power cylinder and said hydraulic actuators, said hydraulic system having delivery and return sides connected to the pressure chambers of said power cylinder and to the individual pressure chambers of said hydraulic actuators, and valve means for connecting the pressure chamber into which said piston is moving always to the delivery side of said hydraulic system and for blocking flow of hydraulic liquid to said hydraulic actuators or for connecting the delivery side of said system selectively to the pressure chamber at one side or the other of the movable actuator element of each hydraulic actuator.

Claim 18

The invention as defined by claim 13 wherein said drive motor is a direct current servomotor.

Claim 19

1 5. The invention as defined by claim 1 3 or claim 14 wherein said connecting means comprises a speed reducer.

Claim 20

1 6. The invention as defined by claim 1 3 wherein said drive motor is a direct current servomotor having a rotatable drive shaft, and wherein said connecting means comprises a rotaryto-linear motion conversion mechanism interconnecting the drive shaft of said servomotor and said piston.

Claim 21

1 7. The invention as defined by claim 1 3 wherein said drive motor is a direct current servomotor having a rotatable drive shaft, and wherein said connecting means comprises a ball screw speed reducer mechanism including a screw shaft having a driven connection with the drive shaft of said servomotor, a ball nut advanceable and retractable on said screw shaft depending on the direction of rotation of said drive shaft, and a carriage connected to and movable with said nut having a driving connection with said piston and operable in use to reciprocably actuate the same in said cylinder, whereby to pump hydraulic liquid alternately from said cylinder at opposite sides of said piston to the delivery side of said hydraulic system.

Claim 22

The invention as defined by claims 13 or 1 7 wherein said valve means includes a plurality of control valves operably associated with said plurality of hydraulic actuators for controlling the flow of hydraulic liquid thereto and being selectively operable individually in predetermined sequence to impart their respective motions to said work actuating means. 1 9. An electro-hydraulic control system for robot devices, such control system being constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.