Fluidic position limit control

Claim 2

A fluidic function generator which comprises: a valve structure comprising an enclosed housing, a sleeve disposed in said housing, and a piston disposed in said sleeve and movable with one degree of freedom relative to said sleeve, said piston comprising a hollow cylindrical member having at least one closed end; input means for moving said piston comprising a shaft extending from said closed end through said housing and sealingly engaged with said housing for movement relative thereto; a pair of porting means in said valve, each porting means comprising a first port extending through the wall of said piston and a second port extending through the wall of said sleeve, said first and said second ports being located and oriented with respect to each other so that movement of said piston will result in movement of said first and second ports with respect to each other to provide a flow area across a said porting means which is defined by two opposed edges of said first port and two opposed edges of said second port; and fluid inlet means for supplying inlet fluid to the interior of said piston.

Claim 3

The function generator recited in claim 1 wherein at least one of said first and second ports included in at least one of said porting means has a varying height which is variably exposed by movement of said piston.

Claim 4

The function generator recited in claim 2 wherein said second port has a varying height exposed by movement of said piston and said first port has a constant height along a line normal to the motion of said piston.

Claim 5

The function generator recited in claim 3 wherein said piston is adapted for rotation only.

Claim 6

The function generator recited in claim 3 wherein said piston is adapted for translational movement only.

Claim 7

The function generator recited in claim 3 wherein each said porting means includes a variable height second port, the said second ports being oriented with respect to each other so that the rate of change of area of said first porting means is the negative of the rate of change of the second porting means.

Claim 8

In a position control system including an actuator for positioning a controlled element and control means therefor, a fluidic position limit control comprising: a. a pair of fluid amplification means each having a power nozzle connected to a source of pressurized fluid and adapted to convert said pressurized fluid to a controllable fluid stream, output means, and a pair of opposed control ports disposed on opposite sides of the axis of said power nozzle; b. a first function generator adapted to generate a fluidic signal proportional to a lower position limit; c. a second function generator adapted to generate a fluidic signal proportional to an upper position limit; d. a third fUnction generator adapted to generate a fluidic signal proportional to the position of said actuator; e. lower limit conduit means connecting said first function generator to the first of said fluid amplifiers and adapted to impress the lower position limit signal upon at least one of the control ports of said first fluid amplification means to promote a corresponding signal from its said output means; f. upper limit conduit means connecting said second function generator to the second of said fluid amplification means and adapted to impress the upper position limit signal upon at least one of the control ports of said second fluid amplifier to promote a corresponding signal from its said output means; g. feedback conduit means connecting said third function generator to each said fluid amplification means and adapted to impress the actuator position signal upon at least one control port in each fluid amplification means to oppose the effect of the said lower and upper position limit signals on the first and second fluid amplification means respectively, whereby a first output signal from the output means of said first fluid amplification means will result which indicates deviation of the actuator position from its lower limit and a second output signal from the output means of said second fluid amplification means will result which indicates deviation of the actuator position from its upper limit; h. override means included in said control means for overriding the effect thereof on said actuator in response to a fluidic signal; and i. means for routing said first and second output signals to said override means so that said first output signal will oppose tendency of the said control means to decrease the position of said actuator and said second output signal will oppose tendency of the said control means to increase the position of said actuator.

Claim 9

In a position control system including an actuator for positioning a controlled element and control means therefor, a fluidic position limit control comprising: a. a pair of fluid amplification means each having a power nozzle connected to a source of pressurized fluid and adapted to convert said pressurized fluid to a controllable fluid stream, output means, and a pair of opposed control ports disposed on opposite sides of the axis of said power nozzle; b. a first function generator adapted to generate a fluidic signal proportional to a lower position limit; c. a second function generator adapted to generate a fluidic signal proportional to an upper position limit; d. a third fUnction generator adapted to generate a fluidic signal proportional to the position of said actuator; e. lower limit conduit means connecting said first function generator to the first of said fluid amplifiers and adapted to impress the lower position limit signal upon at least one of the control ports of said first fluid amplification means to promote a corresponding signal from its said output means; f. upper limit conduit means connecting said second function generator to the second of said fluid amplification means and adapted to impress the upper position limit signal upon at least one of the control ports of said second fluid amplifier to promote a corresponding signal from its said output means; g. feedback conduit means connecting said third function generator to each said fluid amplification means and adapted to impress the actuator position signal upon at least one control port in each fluid amplification means to oppose the effect of the said lower and upper position limit signals on the first and second fluid amplification means respectively, whereby a first output signal from the output means of said first fluid amplification means will result which indicates deviation of the actuator position from its lower limit and a second output signal from the output means of said second fluid amplification means will result which indicates deviation of the actuator position from its upper limit; h. override means included in said control means for overriding the effect thereof on said actuator in response to a fluidic signal; and i. means for routing said first and second output signals to said override means so that said first output signal will oppose tendency of the said control means to decrease the position of said actuator and said second output signal will oppose tendency of the said control means to increase the position of said actuator.

Claim 10

The position limit control recited in claim 7 wherein: said function generators are adapted to generate pressure levels representative of their respective variables; said lower limit conduit means is connected to a first control port in said first fluid amplification means; said upper limit conduit means is connected to a first control port in said second fluid amplification means; and said feedback conduit means is connected to the other of said control ports in each of said first and second fluid amplification means.

Claim 11

The position limit control recited in claim 8 wherein; a. said first and second function generators each comprise a variable restrictor, said variable restrictor including variable area porting means, mechanical input means thereto, fluid inlet means, and fluid discharge means, said variable area porting means having a flow area variation with input which is representative of the respective minimum and maximum position schedules; b. said third function generator comprises a variable restrictor which includes variable area porting means, mechanical input means thereto, fluid inlet means, and fluid discharge means, said porting means having a linear flow area variation with input; and c. the fluid inlet means of said function generators are connected to a common source of pressurized fluid, whereby the discharge pressures of said function generators are representative of the respective functions generated in equal proportions to each other.

Claim 12

The position limit control recited in claim 7 wherein: said function generators are each adapted to generate two flow signals, the difference between which is representative of the respective variable represented; said lower limit conduit means comprises a first conduit connecting the first of said two lower limit flow signals to a first control port in said first fluid amplification means and a second conduit connecting the second of said lower limit flow signals to the second control port in said first fluid amplification means; said upper limit conduit means comprises a third conduit cOnnecting the first of said upper limit flow signals to a first control port in said second fluid amplification means and a fourth conduit connecting the second of said upper limit flow signals to the second control port in said second fluid amplification means; said feedback conduit means comprises a fifth conduit connecting the first of said two feedback flow signals to the second control port in each of said fluid amplification means and a sixth conduit connecting the second of said feedback flow signals to the first control port in each of said fluid amplification means; and said conduit means being connected so as to add the higher of said feedback flow signals to the lower of said lower limit and upper limit flow signals and the lower of said feedback flow signals to the higher of said lower limit and upper limit flow signals.

Claim 13

The position limit control recited in claim 10 wherein; said output means comprises a pair of receivers symmetrically disposed with respect to the axis of said power nozzle, the proportion of said fluid stream being directed into the first of said receivers being greater than that directed into the second of said receivers when the pressure at said first control port exceeds that at said second control port and vice versa; said first receiver in said first fluid amplifier is connected to provide the said first output signal; said second receiver in said second fluid amplifier is connected to provide the said second output signal; and the remaining said receivers are connected to a common ground pressure sink.

Claim 14

The position limit control in claim 11 wherein; said function generators each comprise a valve structure which includes a pair of porting means, fluid inlet means common to both said porting means, separate fluid discharge means for each said porting means, and input means for operating said porting means, at least one of said porting means being variable in area in response to operation of the said input means according to the function desired to be generated, the change in area of the first of said variable area porting means being oppositely directed to the change in area of the other of said variable area porting means.

Claim 15

The position limit control recited in claim 12 wherein said control includes a common source of pressurized fluid connected to the fluid inlet means of each of said function generators.

Claim 16

The position limit control recited in claim 13 wherein; said control means comprises a jet pipe servo valve which includes a jet pipe for converting pressurized fluid into a high velocity fluid jet stream, receiving means for converting the kinetic energy of said jet stream to pressure energy, and means for changing the relative proportion of the said jet stream received by said receiving means; and said override means comprises a pair of override ports oppositely disposed with respect to the axis of said jet pipe and adapted to issue control streams in response to said output signals which control streams will affect the relative proportion of said jet stream received by said receiving means.

Claim 17

The position limit control recited in claim 14 wherein said override ports are located on a line passing between said jet pipe and said receiving means and are adapted to issue control streams which will affect the proportion of said jet stream received by said receiving means by momentum interaction between said control streams and said jet stream.

Claim 18

The position limit control recited in claim 15 wherein: said jet pipe is movable with respect to said receiving means and includes a reaction surface disposed on each side thereof; and said override ports are located on a line passing through said reaction surfaces perpendicularly to said jet pipe, whereby the interaction of control streams issuing from said override ports with said reaction surfaces will create forces tending to move said jet pipe with respect to said receiving means.