US4807153A
Expired / Lapsed
US
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Multiaxis digital robot control having a backup velocity monitor and protection system
Assignee: Staeubli International AG
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Filing: 1986-11-20
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Granted: 1989-02-21
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Expires: 2006-11-20
Abstract
Abstract A digital robot control includes a position/velocity microprocessor control and a torque microprocessor control for each of multiple robot axes. Digital position, velocity and motor current feedback signals are generated from motor sensor signals for use in making microprocessor control calculations. A backup velocity determination is made for each joint motor by the torque microprocessor from the motor current feedback, the motor command terminal voltage and the motor resistance and inductance. The robot is shut down if the difference between the feedback and backup velocity values exceeds a predetermined limit.
Inventors
- 👤 Eimei M. Onaga
- 👤 Richard J. Casler, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:31
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/406; G05B19/4062; G05B2219/00; G05B2219/30; G05B2219/33; G05B2219/33337; G05B2219/37; G05B2219/37312; G05B2219/37313; G05B2219/42; G05B2219/42256; G05B2219/42289; G05B2219/42318; G05B2219/45; G05B2219/45083
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
175 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; each joint motor having digital feedback control loop means operable at a predetermined sampling rate and including digital position and velocity control loops driving a digital torque control loop in accordance with digital position commands to generate digital motor voltage commands for controlling the associated power amplifier; means for sensing the motion of each joint motor and for generating corresponding digital position and primary velocity feedback signals for control calculations in said position and velocity control loops; means for generating digital signals representative of the respective joint motor drive currents for control calculations in said torque control loop; and backup velocity monitoring means independently determining the velocity of each joint motor from the motor current and terminal voltage and the motor inductance and resistance; and means for comparing said primary and backup velocity signals for each joint motor.
Claim 2
Dependent Claim
175 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; each joint motor having digital feedback control loop means operable at a predetermined sampling rate and including digital position and velocity control loops driving a digital torque control loop in accordance with digital position commands to generate digital motor voltage commands for controlling the associated power amplifier; means for sensing the motion of each joint motor and for generating corresponding digital position and primary velocity feedback signals for control calculations in said position and velocity control loops; means for generating digital signals representative of the respective joint motor drive currents for control calculations in said torque control loop; and backup velocity monitoring means independently determining the velocity of each joint motor from the motor current and terminal voltage and the motor inductance and resistance; and means for comparing said primary and backup velocity signals for each joint motor.
Claim 3
Dependent Claim
37 words
A digital robot control as set forth in claim 1 wherein means are provided for shutting down the robot operation if the difference between the primary and backup voltages for any joint motor exceeds a predetermined limit.
Claim 4
Dependent Claim
32 words
A digital robot control as set forth in claim 1 wherein the motor current and voltage values are average values computed for a predetermined time period next preceding the current control cycle.
Claim 5
Dependent Claim
23 words
A digital robot control as set forth in claim 1 wherein the following formula is employed in the backup velocity calculation: VEL=w*Ke=Vin-(L*di/dt+iR) where:
Claim 6
Dependent Claim
3 words
R=motor resistant [ohm]
Claim 7
Dependent Claim
3 words
R=motor resistant [ohm]
Claim 8
Dependent Claim
3 words
L=motor inductance [H]
Claim 9
Dependent Claim
3 words
L=motor inductance [H]
Claim 10
Dependent Claim
4 words
Vin=motor terminal voltage [V]
Claim 11
Dependent Claim
4 words
Vin=motor terminal voltage [V]
Claim 12
Dependent Claim
4 words
Ke=motor Back-emf constant [V/rad/sec]
Claim 13
Dependent Claim
4 words
Ke=motor Back-emf constant [V/rad/sec]
Claim 14
Dependent Claim
3 words
w=motor velocity [rad/sec]
Claim 15
Dependent Claim
3 words
w=motor velocity [rad/sec]
Claim 16
Dependent Claim
3 words
i=motor current [A]
Claim 17
Dependent Claim
3 words
i=motor current [A]
Claim 18
Dependent Claim
74 words
A digital robot control as set forth in claim 1 wherein each of said motor torque control loops includes torque servo control means having microprocessor means for generating motor voltage commands from torque commands and motor current feedback signals; and another servo control means having another microprocessor means included in each of said motor velocity control loops and generating torque commands in response to position and velocity commands and position and velocity feedback signals.
Claim 19
Dependent Claim
30 words
A digital robot control as set forth in claim 5 wherein said torque microprocessor means includes said backup velocity monitoring means and said other microprocessor means includes said comparing means.
Claim 20
Dependent Claim
41 words
A digital robot control as set forth in claim 6 wherein said other microprocessor means further includes means for shutting down the robot operation if the difference between the primary and backup voltages for any joint motor exceeds a predetermined limit.
Claim 21
Dependent Claim
170 words
A robot comprising: an arm having a plurality of joints; an electric motor for driving each of the robot arm joints; a power amplifier operable to supply drive current to each motor; each joint motor having digital feedback control loop means operable at a predetermined sampling rate and including digital position and velocity control loops driving a digital torque control loop in accordance with digital position commands to generate digital motor voltage commands for controlling the associated power amplifier; means for sensing the motion of each joint motor and for generating corresponding digital position and primary velocity feedback signals for control calculations in said position and velocity control loops; means for generating digital signals representative of the respective joint motor drive currents for control calculations in said torque control loop; and backup velocity monitoring means independently determining the velocity of each joint motor from the motor current and terminal voltage and the motor inductance and resistance; and means for comparing said primary and backup velocity signals for each joint motor.
Claim 22
Dependent Claim
170 words
A robot comprising: an arm having a plurality of joints; an electric motor for driving each of the robot arm joints; a power amplifier operable to supply drive current to each motor; each joint motor having digital feedback control loop means operable at a predetermined sampling rate and including digital position and velocity control loops driving a digital torque control loop in accordance with digital position commands to generate digital motor voltage commands for controlling the associated power amplifier; means for sensing the motion of each joint motor and for generating corresponding digital position and primary velocity feedback signals for control calculations in said position and velocity control loops; means for generating digital signals representative of the respective joint motor drive currents for control calculations in said torque control loop; and backup velocity monitoring means independently determining the velocity of each joint motor from the motor current and terminal voltage and the motor inductance and resistance; and means for comparing said primary and backup velocity signals for each joint motor.
Claim 23
Dependent Claim
35 words
A robot as set forth in claim 8 wherein means are provided for shutting down the robot operation if the difference between the primary and backup voltages for any joint motor exceeds a predetermined limit.
Claim 24
Dependent Claim
72 words
A robot as set forth in claim 8 wherein each of said motor torque control loops includes torque servo control means having microprocessor means for generating motor voltage commands from torque commands and motor current feedback signals; and another servo control means having another microprocessor means included in each of said motor velocity control loops and generating torque commands in response to position and velocity commands and position and velocity feedback signals.
References Cited (Backward Citations)
US4159444A
Cited
US4362978A
Cited
US4506321A
Cited
US4535405A
Cited
US4623971A
Cited
US4603284A
Cited
US4598380A
Cited
US4695941A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |