US4786847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital control for multiaxis robots
Assignee: Staeubli International AG
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Filing: 1986-11-20
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Granted: 1988-11-22
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Expires: 2006-11-20
Abstract
Abstract A completely digital robot control operates at a predetermined sampling rate. The robot arm has a plurality of joints with each driven by an electric brushless or brush-type DC motor which is in turn supplied with drive current by a power amplifier bridge circuit having power switches connected therein to supply motor winding current in the forward or reverse direction. Incremental or absolute encoders and tachometers provide for generating digital position and velocity feedback signals generated synchronously with the sampling rate. Digital motor current feedback signals are also generated synchronously with the sampling rate. Paired position/velocity microprocessors generate torque commands for each of the robot axes at the sampling rate in response to the position commands and the position and velocity feedback signals. Paired torque microprocessors generate motor voltage commands for each of the robot axes at the sampling rate in response to the torque commands and the current feedback signals. Pulse width modulators generate digital motor control signals for each of the robot axes at the sampling rate in response to the voltage commands. The digital control signals for each axis are coupled to control terminals of the corresponding power switches to control on/off switch time and satisfy the motor voltage commands and thereby satisfy the position commands.
Inventors
- 👤 Kenneth E. Daggett
- 👤 Eimei M. Onaga
- 👤 Richard J. Casler, Jr.
- 👤 Barrett L. Booth
- 👤 Rajan C. Penkar
- 👤 Leonard C. Vercellotti
- 👤 Richard A. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:47
CPC Classifications
B; B25; B25J; B25J9/00; B25J9/16; B25J9/1628; B25J9/1633; G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/414; G05B19/4141; G05B2219/00; G05B2219/30; G05B2219/33; G05B2219/33337; G05B2219/41; G05B2219/41426; G05B2219/42; G05B2219/42237; G05B2219/42256
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
293 words
A completely digital control for a robot operating at a predetermined sampling rate and having an arm with each of a plurality of joints driven by an electric DC motor, each of said DC motors in turn supplied with drive current by a power amplifier bridge circuit having power switches connected therein to supply motor winding current in the positive direction or the negative direction, said robot control comprising: digital means for generating position commands at the sampling rate for each of the robot axes in accordance with a stored robot program; means for sensing the position of each of said motors; means for generating digital position feedback signals synchronously with the sampling rate in response to said position sensing means; means for generating digital velocity feedback signals synchronously with the sampling rate for each of said motors; means for sensing the polarity and magnitude of motor current for each of said joint motors; means for generating digital current feedback signals synchronously with the sampling rate in response to said current sensing means; digital means for generating torque commands for each of the robot axes at the sampling rate in response to said position commands and said position and velocity feedback signals; digital means for generating motor voltage commands for each of the robot axes at the sampling rate in response to said torque commands and said digital current feedback signals; pulse width modulation means for generating digital motor control signals for each of the robot axes at the sampling rate in response to said voltage commands; and means for coupling said digital control signals for each axis to control terminals of the corresponding power switches to control on/off switch time and satisfy said motor voltage commands and thereby satisfy said position commands.
Claim 2
Dependent Claim
293 words
A completely digital control for a robot operating at a predetermined sampling rate and having an arm with each of a plurality of joints driven by an electric DC motor, each of said DC motors in turn supplied with drive current by a power amplifier bridge circuit having power switches connected therein to supply motor winding current in the positive direction or the negative direction, said robot control comprising: digital means for generating position commands at the sampling rate for each of the robot axes in accordance with a stored robot program; means for sensing the position of each of said motors; means for generating digital position feedback signals synchronously with the sampling rate in response to said position sensing means; means for generating digital velocity feedback signals synchronously with the sampling rate for each of said motors; means for sensing the polarity and magnitude of motor current for each of said joint motors; means for generating digital current feedback signals synchronously with the sampling rate in response to said current sensing means; digital means for generating torque commands for each of the robot axes at the sampling rate in response to said position commands and said position and velocity feedback signals; digital means for generating motor voltage commands for each of the robot axes at the sampling rate in response to said torque commands and said digital current feedback signals; pulse width modulation means for generating digital motor control signals for each of the robot axes at the sampling rate in response to said voltage commands; and means for coupling said digital control signals for each axis to control terminals of the corresponding power switches to control on/off switch time and satisfy said motor voltage commands and thereby satisfy said position commands.
Claim 3
Dependent Claim
27 words
A digital robot control as set forth in claim 1 wherein said velocity feedback signal generating means includes a tachometer coupled to each of the joint motors.
Claim 4
Dependent Claim
52 words
A digital robot control as set forth in claim 1 wherein said digital means for generating torque commands includes a microprocessor system having a data manager microprocessor and a position/velocity calculating microprocessor coupled together, said data manager microprocessor controlling the timing and flow of control data to and from said calculating microprocessor.
Claim 5
Dependent Claim
51 words
A digital robot control as set forth in claim 1 wherein said motor voltage command generating means includes a microprocessor system having a data manager microprocessor and a torque calculating microprocessor coupled together, said data manager microprocessor controlling the timing and flow of control data to and from said calculating microprocessor.
Claim 6
Dependent Claim
54 words
A digital robot control as set forth in claim 4 wherein said digital means for generating torque commands includes a microprocessor system having a position/velocity data manager microprocessor and a position/velocity calculating microprocessor coupled together, said position/velocity data manager microprocessor controlling the timing and flow of control data to and from said calculating microprocessor.
Claim 7
Dependent Claim
61 words
A digital robot control as set forth in claim 3 wherein said position digital means for generating commands includes stored program means for generating position commands from programmed robot moves, said microprocessor system includes said position command generating means, and said data manager microprocessor executes said program means and manages the operation of said microprocessor system to generate said position commands.
Claim 8
Dependent Claim
72 words
A digital robot control as set forth in claim 3 wherein said digital means for generating commands includes stored program means for generating position commands from programmed robot moves and further includes a system data manager microprocessor and a system position command calculating microprocessor coupled together, said system data manager microprocessor executing said program means and controlling the timing and flow of control data to and from said position command calculating microprocessor.
Claim 9
Dependent Claim
71 words
A digital robot control as set forth in claim 5 wherein said digital means for generating includes stored program means for generating position commands from programmed robot moves and further includes a system data manager microprocessor and a system position command calculating microprocessor coupled together, said system data manager microprocessor executing said program means and controlling the timing and flow of control data to and from said position command calculating microprocessor.
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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) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |