US4876494A
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Position and velocity feedback system for a digital robot control
Assignee: Staeubli International AG
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Filing: 1988-04-01
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Granted: 1989-10-24
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Expires: 2008-04-01
Abstract
Abstract A digital position and velocity feedback system is provided for a multiaxis robot control and it employs an LSI chip to process incremental position signals for position change and velocity computations. At low speeds, velocity is computed from the reciprocal of elasped time. At higher speeds, velocity is computed from the rate at which incremental position signals are generated.
Inventors
- 👤 Kenneth E. Daggett
- 👤 Eimei M. Onaga
- 👤 Richard J. Casler, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:35
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/414; G05B19/4141; G05B2219/00; G05B2219/30; G05B2219/33; G05B2219/33337; G05B2219/42; G05B2219/42256
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
268 words
A digital control for a robot having a plurality of arm joints, said control comprising: an electric motor constituting a joint motor for driving each of the robot arm joints; a power amplifier operable to supply drive current to each joint motor; feedback control loop means for each joint motor including at least digital position and velocity control loops operable at a predetermined sampling rate to control the associated power amplifier; encoder means for generating a plurality of signals representing joint motor position changes; a digital feedback system responsive to said encoder means to provide position and velocity feedback signals for said feedback control means at the predetermined sampling rate; said feedback system including circuit means having means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as said position feedback signal for said feedback control means; said circuit means further having means for detecting the elapsed time between successive increment pulses, the elapsed time being detected by first determining the time interval between the start of a sample pulse and the start of a first increment pulse which occurs before the next sample pulse, and for adding the time interval between the end of the last increment pulse in the sample period and the start of the next sample pulse, which defines the sample period, and then subtracting this time interval summation from the time period between the two sample pulses which define the sample period. and means for computing velocity from the elapsed time and generating said velocity feedback signal for said feedback control means.
Claim 2
Dependent Claim
268 words
A digital control for a robot having a plurality of arm joints, said control comprising: an electric motor constituting a joint motor for driving each of the robot arm joints; a power amplifier operable to supply drive current to each joint motor; feedback control loop means for each joint motor including at least digital position and velocity control loops operable at a predetermined sampling rate to control the associated power amplifier; encoder means for generating a plurality of signals representing joint motor position changes; a digital feedback system responsive to said encoder means to provide position and velocity feedback signals for said feedback control means at the predetermined sampling rate; said feedback system including circuit means having means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as said position feedback signal for said feedback control means; said circuit means further having means for detecting the elapsed time between successive increment pulses, the elapsed time being detected by first determining the time interval between the start of a sample pulse and the start of a first increment pulse which occurs before the next sample pulse, and for adding the time interval between the end of the last increment pulse in the sample period and the start of the next sample pulse, which defines the sample period, and then subtracting this time interval summation from the time period between the two sample pulses which define the sample period. and means for computing velocity from the elapsed time and generating said velocity feedback signal for said feedback control means.
Claim 3
Dependent Claim
47 words
A robot control as set forth in claim 1 wherein means are provided for computing velocity from the number of increment pulses generated over a reference time period and means are provided for selecting one of the two computed velocities for use as said velocity feedback signal.
Claim 4
Dependent Claim
40 words
A robot control as set forth in claim 2 wherein the velocity selection is based on the rate of increment pulse generation with the elapsed time velocity selected for lower velocities and the increment pulse velocity selected for higher velocities.
Claim 5
Dependent Claim
258 words
A digital control for a robot having a plurality of arm joints, said control comprising: an electric motor for driving each of the robot arm joints; a power amplifier operable to supply drive current to each motor; feedback control loop means for each motor including at least digital position and velocity control loops operable at a predetermined sampling rate to control the associated power amplifier; encoder means for generating a plurality of signals representing motor position changes; a digital feedback system responsive to said encoder means to provide position and velocity feedback signals for said feedback control means at the predetermined sampling rate; said feedback system including circuit means having means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as said position feedback signal for said feedback control means; said circuit means further having means for cyclically generating a sample pulse synchronized to the predetermined sampling rate of said position and velocity control loops; means for detecting the time elapsed from the sample pulse marking the beginning of each sample period to the beginning of the first increment pulse in that sample period; means for detecting the time elapsed from the end of the last increment pulse in each sample period to the sample pulse marking the end of that sample period; and means for computing velocity from the elapsed time between successive last and first increment pulses with respect to each sample period and for generating said velocity feedback signal for said feedback control means.
Claim 6
Dependent Claim
258 words
A digital control for a robot having a plurality of arm joints, said control comprising: an electric motor for driving each of the robot arm joints; a power amplifier operable to supply drive current to each motor; feedback control loop means for each motor including at least digital position and velocity control loops operable at a predetermined sampling rate to control the associated power amplifier; encoder means for generating a plurality of signals representing motor position changes; a digital feedback system responsive to said encoder means to provide position and velocity feedback signals for said feedback control means at the predetermined sampling rate; said feedback system including circuit means having means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as said position feedback signal for said feedback control means; said circuit means further having means for cyclically generating a sample pulse synchronized to the predetermined sampling rate of said position and velocity control loops; means for detecting the time elapsed from the sample pulse marking the beginning of each sample period to the beginning of the first increment pulse in that sample period; means for detecting the time elapsed from the end of the last increment pulse in each sample period to the sample pulse marking the end of that sample period; and means for computing velocity from the elapsed time between successive last and first increment pulses with respect to each sample period and for generating said velocity feedback signal for said feedback control means.
Claim 7
Dependent Claim
47 words
A robot control as set forth in claim 4 wherein means are provided for computing velocity from the number of increment pulses generated over a reference time period and means are provided for selecting one of the two computed velocities for use as said velocity feedback signal.
Claim 8
Dependent Claim
40 words
A robot control as set forth in claim 5 wherein the velocity selection is based on the rate of increment pulse generation with the elapsed time velocity selected for lower velocities and the increment pulse velocity selected for higher velocities.
Claim 9
Dependent Claim
179 words
A robot comprising: an arm having a plurality of joints; each of said joints being driven by an electric motor drive; a power amplifier operable to supply drive current to each joint drive motor; feedback control loop means for each joint drive motor including at least digital position and velocity control loops operable at a predetermined sampling rate to control the associated power amplifier; encoder means for generating a plurality of signals representing motor position changes; a digital feedback system responsive to said encoder means to provide position and velocity feedback signals for said feedback control means at the predetermined sampling rate; said feedback system including circuit means having means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as said position feedback signal for said feedback control means; said circuit means further having means for detecting the elapsed time between successive increment pulses relative to a sample period and for computing velocity from the elapsed time and generating said velocity feedback signal for said feedback control means.
Claim 10
Dependent Claim
179 words
A robot comprising: an arm having a plurality of joints; each of said joints being driven by an electric motor drive; a power amplifier operable to supply drive current to each joint drive motor; feedback control loop means for each joint drive motor including at least digital position and velocity control loops operable at a predetermined sampling rate to control the associated power amplifier; encoder means for generating a plurality of signals representing motor position changes; a digital feedback system responsive to said encoder means to provide position and velocity feedback signals for said feedback control means at the predetermined sampling rate; said feedback system including circuit means having means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as said position feedback signal for said feedback control means; said circuit means further having means for detecting the elapsed time between successive increment pulses relative to a sample period and for computing velocity from the elapsed time and generating said velocity feedback signal for said feedback control means.
Claim 11
Dependent Claim
46 words
A robot as set forth in claim 7 wherein means are provided for computing velocity from the number of increment pulses generated over a reference time period and means are provided for selecting one of the two computed velocities for use as said velocity feedback signal.
Claim 12
Dependent Claim
39 words
A robot as set forth in claim 8 wherein the velocity selection is based on the rate of increment pulse generation with the elapsed time velocity selected for lower velocities and the increment pulse velocity selected for higher velocities.
Claim 13
Dependent Claim
117 words
A digital position and velocity feedback system for a digital control for a robot having a plurality of arm joints, said system comprising: an electric motor for driving each of the robot arm joints in accordance with operation of the digital control; encoder means for generating a plurality of signals representing motor position changes; first circuit means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as a position feedback signal; said first circuit means further having means for detecting the elapsed time between successive increment pulses relative to a sample period and for computing velocity from the elapsed time and generating a velocity feedback signal.
Claim 14
Dependent Claim
117 words
A digital position and velocity feedback system for a digital control for a robot having a plurality of arm joints, said system comprising: an electric motor for driving each of the robot arm joints in accordance with operation of the digital control; encoder means for generating a plurality of signals representing motor position changes; first circuit means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as a position feedback signal; said first circuit means further having means for detecting the elapsed time between successive increment pulses relative to a sample period and for computing velocity from the elapsed time and generating a velocity feedback signal.
Claim 15
Dependent Claim
46 words
A system as set forth in claim 10 wherein means are provided for computing velocity from the number of increment pulses generated over a reference time period and means are provided for selecting one of the two computed velocities for use as said velocity feedback signal.
Claim 16
Dependent Claim
39 words
A system as set forth in claim 11 wherein the velocity selection is based on the rate of increment pulse generation with the elapsed time velocity selected for lower velocities and the increment pulse velocity selected for higher velocities.
Claim 17
Dependent Claim
24 words
A system as set forth in claim 10 wherein a large scale integrated gate array chip is structured to embody said first circuit means.
Claim 18
Dependent Claim
198 words
A digital position and velocity feedback system for a digital control for a robot having a plurality of arm joints, said system comprising: an electric motor for driving each of the robot arm joints in accordance with operation of the digital control; encoder means for generating a plurality of signals representing motor position changes; circuit means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as a position feedback signal; said circuit means further having means for detecting the elapsed time between successive increment pulses relative to a sample period and for computing velocity from the elapsed time and generating a velocity feedback signal; said circuit means further having means for cyclically generating a sample pulse synchronized to the predetermined sampling rate of said position and velocity control loops; means for detecting the time elapsed from the sample pulse marking the beginning of each sample period to the beginning of the first increment pulse in that sample period; means for detecting the time elapsed from the end of the last increment pulse in each sample period to the sample pulse marking the end of that sample period.
Claim 19
Dependent Claim
198 words
A digital position and velocity feedback system for a digital control for a robot having a plurality of arm joints, said system comprising: an electric motor for driving each of the robot arm joints in accordance with operation of the digital control; encoder means for generating a plurality of signals representing motor position changes; circuit means responsive to said encoder means signals to accumulate a count of increment pulses representing incremental changes in position and operating as a position feedback signal; said circuit means further having means for detecting the elapsed time between successive increment pulses relative to a sample period and for computing velocity from the elapsed time and generating a velocity feedback signal; said circuit means further having means for cyclically generating a sample pulse synchronized to the predetermined sampling rate of said position and velocity control loops; means for detecting the time elapsed from the sample pulse marking the beginning of each sample period to the beginning of the first increment pulse in that sample period; means for detecting the time elapsed from the end of the last increment pulse in each sample period to the sample pulse marking the end of that sample period.
Claim 20
Dependent Claim
125 words
A system as set forth in claim 10 wherein: said first circuit means further includes second circuit means having means for cyclically generating a sample pulse synchronized to the predetermined sampling rate of said position and velocity control loops; means for detecting the time elapsed from the sample pulse marking the beginning of each sample period to the beginning of the first increment pulse in that sample period; means for detecting the time elapsed from the end of the last increment pulse in each sample period to the sample pulse marking the end of that sample period; and means for computing velocity from the elapsed time between successive last and first increment pulses and for generating said velocity feedback signal for said feedback control means.
Claim 21
Dependent Claim
24 words
A system as set forth in claim 15 wherein a large scale integrated gate array chip is structured to embody said second circuit means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-23 | 1993-04-24 | 1993-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-23 | 1997-04-24 | 1997-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-23 | 2001-04-24 | 2001-10-24 | $7700.00 | Window Closed / Lapsed |