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US5674194A
Expired / Lapsed
US
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Process control system
Assignee: Alcon Research LLC
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Filing: 1995-10-25
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Granted: 1997-10-07
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Expires: 2015-10-25
Abstract
Abstract A process control system according to the present invention uses analog control circuitry in which a differential amplifier stage is incorporated into the feedback path rather that the feedforward path to enable the control of highly non-linear processes that may also exhibit high levels of hysteresis. Such processes often have superior performance characteristics that conventional control circuitry cannot exploit. The present invention additionally incorporates an automatic control circuit which varies the gain of various stages the control circuitry when the output of the process is within a predetermined range. An embodiment of the present invention is used to control a nonlinear proportional valve with severe hysteresis. The valve regulates the pressure within pressure-driven ophthalmic surgical instruments, which must be controlled extremely precisely to enable successful eye surgery.
Inventors
- 👤 Christopher C. Jung
- 👤 Douglas E. Wallace, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:27
CPC Classifications
G; G05; G05B; G05B11/00; G05B11/01; G05B11/36; G05B11/42; A; A61; A61M; A61M1/00; A61M1/71; A61M1/74; A61M1/743; A61M1/80; A61M1/804; G05D; G05D16/00; G05D16/20; G05D16/2006; G05D16/2013; G05D16/202; A61F; A61F9/00; A61F9/007; A61F9/00736; A61M2205/00; A61M2205/33; A61M2205/3331; A61M2210/00; A61M2210/06; A61M2210/0612
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
105 words
A system for controlling a process that responds to changes in a drive signal, comprising: a. a means for generating a desired process status signal; b. a proportional amplifier stage that generates the drive signal, the proportional amplifier staging including i) an inverting input, ii) a non-inverting input to which the desired process status signal is connected and iii) a first variable resistor; c. a process sensor that generates an actual process status signal; and d. a differential amplifier stage using the actual process status signal to generate a feedback signal, the feedback signal being connected to the inverting input of the proportional amplifier stage.
Claim 2
Independent Claim
105 words
A system for controlling a process that responds to changes in a drive signal, comprising: a. a means for generating a desired process status signal; b. a proportional amplifier stage that generates the drive signal, the proportional amplifier staging including i) an inverting input, ii) a non-inverting input to which the desired process status signal is connected and iii) a first variable resistor; c. a process sensor that generates an actual process status signal; and d. a differential amplifier stage using the actual process status signal to generate a feedback signal, the feedback signal being connected to the inverting input of the proportional amplifier stage.
Claim 3
Dependent Claim
19 words
The process control system of claim 1 in which the differential amplifier stage further comprises a second variable resistor.
Claim 4
Dependent Claim
19 words
The process control system of claim 2 in which the first and second variable resistors are light dependent resistors.
Claim 5
Dependent Claim
23 words
The process control system of claim 3 further comprising an integral amplifier stage that is connected in parallel to the proportional amplifier stage.
Claim 6
Dependent Claim
32 words
The process control system of claim 3 further comprising a means for varying the resistance of the first variable resistor and a means for varying the resistance of the second variable resistor.
Claim 7
Dependent Claim
23 words
The process control system of claim 1 further comprising an integral amplifier stage that is connected in parallel with the proportional amplifier stage.
Claim 8
Dependent Claim
145 words
A pressure control system comprising: a. a means for generating a desired pressure signal; b. a proportional amplifier stage that generates a drive signal and includes: i) an inverting input, ii) a non-inverting input to which the desired pressure signal is connected and iii) a first variable resistor; c. a pneumatic system comprising: i) a regulated high pressure source, ii) a proportional valve, the position of which is determined by the drive signal, and iii) an output manifold with the regulated high pressure source, the proportional valve, and the output manifold respectively pneumatically connected in series; d. a pressure transducer that generates an actual pressure signal in proportion to the pressure in the output manifold; and e. a differential amplifier stage using the actual pressure signal to generate a feedback signal, which feedback signal is connected to the inverting input of the proportional amplifier stage.
Claim 9
Dependent Claim
145 words
A pressure control system comprising: a. a means for generating a desired pressure signal; b. a proportional amplifier stage that generates a drive signal and includes: i) an inverting input, ii) a non-inverting input to which the desired pressure signal is connected and iii) a first variable resistor; c. a pneumatic system comprising: i) a regulated high pressure source, ii) a proportional valve, the position of which is determined by the drive signal, and iii) an output manifold with the regulated high pressure source, the proportional valve, and the output manifold respectively pneumatically connected in series; d. a pressure transducer that generates an actual pressure signal in proportion to the pressure in the output manifold; and e. a differential amplifier stage using the actual pressure signal to generate a feedback signal, which feedback signal is connected to the inverting input of the proportional amplifier stage.
Claim 10
Dependent Claim
18 words
The pressure control system of claim 7 further comprising an ophthalmic surgical instrument connected to the output manifold.
Claim 11
Dependent Claim
38 words
The pressure control system of claim 7 further comprising a venturi having a vacuum manifold, which venturi is connected between the proportional valve and the output manifold such that the vacuum manifold is connected to the output manifold.
Claim 12
Dependent Claim
18 words
The pressure control system of claim 9 further comprising an ophthalmic surgical instrument connected to the output manifold.
Claim 13
Dependent Claim
19 words
The pressure control system of claim 7 in which the differential amplifier stage further comprises a second variable resistor.
Claim 14
Dependent Claim
19 words
The pressure control system of claim 11 in which the first and second variable resistors are light dependent resistors.
Claim 15
Dependent Claim
32 words
The pressure control system of claim 12 further comprising a means for varying the resistance of the first variable resistor and a means for varying the resistance of the second variable resistor.
Claim 16
Dependent Claim
23 words
The pressure control system of claim 7 further comprising an integral amplifier stage that is connected in parallel to the proportional amplifier stage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-10-06 | 2001-04-07 | 2001-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-10-06 | 2005-04-07 | 2005-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-10-06 | 2009-04-07 | 2009-10-07 | $7700.00 | Window Closed / Lapsed |