US5826666A
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US
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Apparatus and method for controlling a contruction machine
Assignee: Caterpillar SARL
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Filing: 1996-09-11
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Granted: 1998-10-27
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Expires: 2016-09-11
Abstract
Abstract The finishing precision and uniformity of hardness of a surface finished by a construction machine, such as back-hoe, is improved by modifying the targets of a position-tracking control system based on work-load applied to the end effector of the construction machine. For example, compaction of a surface, contoured by a position-tracking, back-hoe, can be made more uniform. This is accomplished by adjusting actuator targets, otherwise controlled on the basis of positional and speed constraints, in response to a detected work load acting on the end effector. To detect work load, a hydraulic fluid pressure signal can be applied to a computer which generates target position and speed commands to the feedback system. The control circuit may be arranged to hold work load constant (generating a constant compaction force for example) or, in response to a priority signal, the circuit can give a selected weight to both the positional constraints and the work load constraints. Another benefit of altering position-tracking in response to work load is improved coordination of actuators. For example, the gain of feedback and feedforward signals of a position-tracking control system can be increased when a detected load is heavy, increasing response, and attenuated when the load is light.
Inventors
- 👤 Shoji Tozawa
- 👤 Tomoaki Ono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:04
CPC Classifications
E; E02; E02F; E02F9/00; E02F9/20; E02F3/00; E02F3/04; E02F3/28; E02F3/36; E02F3/42; E02F3/43; E02F3/435; E02F3/437
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
92 words
A control method for controlling a piece of construction equipment that has a position-sensing feedback control system to track respective positions of an actuator that controls positions of an end effector, comprising the steps of: generating a target value for an actual force-load acting on said actuator generated in response to a forcing of said end effector against a working material; detecting said actual force-load acting on said actuator; and modifying a control signal of said feedback control system responsively to a result of said step of detecting and said target value.
Claim 2
Dependent Claim
92 words
A control method for controlling a piece of construction equipment that has a position-sensing feedback control system to track respective positions of an actuator that controls positions of an end effector, comprising the steps of: generating a target value for an actual force-load acting on said actuator generated in response to a forcing of said end effector against a working material; detecting said actual force-load acting on said actuator; and modifying a control signal of said feedback control system responsively to a result of said step of detecting and said target value.
Claim 3
Dependent Claim
21 words
A method as in claim 1, wherein said step of detecting includes detecting a pressure of hydraulic fluid of said actuator.
Claim 4
Dependent Claim
30 words
A method as in claim 2, wherein said step of detecting includes detecting a differential pressure of a hydraulic fluid acting on extension and retraction sides of a linear actuator.
Claim 5
Dependent Claim
30 words
A method as in claim 1, wherein said step of detecting includes detecting a differential pressure of hydraulic fluid acting on extension and retraction sides of a hydraulic linear actuator.
Claim 6
Dependent Claim
34 words
A method as in claim 1, wherein said step of modifying includes establishing a target speed of a component of movement of said end effector, said component being chosen to affect said actual force-load.
Claim 7
Dependent Claim
56 words
A method as in claim 1, further comprising the steps of: establishing a priority between a position-tracking control-goal of said position-sensing feedback control system and said target-value of said force-load; generating at least one of a target speed of said actuator and a target position of said actuator responsively to said step of establishing a priority.
Claim 8
Dependent Claim
67 words
A method as in claim 6, wherein: said load force-load being proportional to a soil compaction force generated by said piece of construction equipment; said step of generating at least one of a target speed of said actuator and a target position of said actuator includes determining a position of said end effector in a direction normal to a surface worked by said piece of construction equipment.
Claim 9
Dependent Claim
50 words
A method as in claim 1, wherein: said load force-load being proportional to a soil compaction force generated by said piece of construction equipment; said step of generating includes determining a position of said end effector in a direction normal to a surface worked by said piece of construction equipment.
Claim 10
Independent Claim
136 words
An apparatus for controlling an end effector of a construction machine that employs a feedback control system to track respective positions of at least one actuator that moves said end effector comprising: a pressure sensor connected to said at least one actuator to communicate with a hydraulic fluid whose pressure is responsive to a work load affecting said end effector; a work load-setting indicator to allow a user to set a desired signal indicating a target work load; a work load control portion connected to receive said signal indicating a target work load, said work load control portion being connected to said feedback control system to track respective positions such that a tracking of said feedback control system is responsive to said signal indicating a desired work load and a pressure signal of said pressure sensor.
Claim 11
Independent Claim
136 words
An apparatus for controlling an end effector of a construction machine that employs a feedback control system to track respective positions of at least one actuator that moves said end effector comprising: a pressure sensor connected to said at least one actuator to communicate with a hydraulic fluid whose pressure is responsive to a work load affecting said end effector; a work load-setting indicator to allow a user to set a desired signal indicating a target work load; a work load control portion connected to receive said signal indicating a target work load, said work load control portion being connected to said feedback control system to track respective positions such that a tracking of said feedback control system is responsive to said signal indicating a desired work load and a pressure signal of said pressure sensor.
Claim 12
Dependent Claim
37 words
An apparatus as in claim 9, further comprising: a user-actuated priority indicating device; and means for altering a sensitivity of a response of said feedback control system to track respective positions to said work load control portion.
Claim 13
Independent Claim
63 words
An apparatus for controlling an end effector of a construction machine that employs a feedback control system for tracking respective positions of end effector actuators, comprising: a feedforward loop in said position-tracking feedback control system; and an amplifier connected to modulate a signal in said feedforward loop; a gain of said amplifier being responsive to a work load applied to said end effector.
Claim 14
Independent Claim
63 words
An apparatus for controlling an end effector of a construction machine that employs a feedback control system for tracking respective positions of end effector actuators, comprising: a feedforward loop in said position-tracking feedback control system; and an amplifier connected to modulate a signal in said feedforward loop; a gain of said amplifier being responsive to a work load applied to said end effector.
Claim 15
Dependent Claim
46 words
An apparatus as in claim 11, further comprising: a force-sensor connected to said actuator to detect said work load; an output of said force sensor connected to a gain-adjusting input of said amplifier, whereby said gain is adjusted in response to an output of said force-sensor.
Claim 16
Dependent Claim
35 words
An apparatus as in claim 12, wherein: said actuator includes a hydraulic cylinder; said force-sensor includes a pressure sensor connected to said hydraulic cylinder and in communication with a hydraulic fluid of said hydraulic cylinder.
Claim 17
Independent Claim
122 words
An apparatus for controlling an end effector of a construction machine that employs a feedback control system for tracking respective positions of end effector actuating cylinders, said apparatus including: a feedforward loop in said feedback control system; a feedforward amplifier in said feedforward loop to adjust a gain of said feedforward loop; a detector, connected to said feedforward amplifier for detecting a digging work load applied upon said end effector actuating cylinders; said gain of said feedforward amplifier being continuously adjustable responsively to said detector; and a feedback loop with a feedback amplifier in said feedback loop to adjust a gain of a feedback signal of said feedback loop; said gain of said feedback amplifier being continuously adjustable responsively to said detector.
Claim 18
Independent Claim
122 words
An apparatus for controlling an end effector of a construction machine that employs a feedback control system for tracking respective positions of end effector actuating cylinders, said apparatus including: a feedforward loop in said feedback control system; a feedforward amplifier in said feedforward loop to adjust a gain of said feedforward loop; a detector, connected to said feedforward amplifier for detecting a digging work load applied upon said end effector actuating cylinders; said gain of said feedforward amplifier being continuously adjustable responsively to said detector; and a feedback loop with a feedback amplifier in said feedback loop to adjust a gain of a feedback signal of said feedback loop; said gain of said feedback amplifier being continuously adjustable responsively to said detector.
Claim 19
Dependent Claim
81 words
An apparatus as in claim 14 wherein: said construction machine includes a hydraulic cylinder; said detector includes a pressure sensor in communication with a hydraulic fluid of said hydraulic cylinder; said feedforward loop amplifier is connected to said detector through a filter that controls said gain of said feedforward amplifier responsively to said detector and a first set of data stored in a memory, said data indicating a relationship between a desired gain of said feedforward amplifier and digging work load.
Claim 20
Dependent Claim
61 words
A apparatus as in claim 15 wherein said feedback amplifier is connected to said detector through a second filter that controls said gain of said feedforward amplifier responsively to said detector and a second set of data stored in a memory, said second set of data indicating a relationship between a desired gain of said feedback amplifier and digging work load.
Claim 21
Dependent Claim
54 words
An apparatus as in claim 14, wherein said feedback amplifier is connected to said detector through a second filter that controls said gain of said feedforward amplifier responsively to said detector and data stored in a memory, said data indicating a relationship between a desired gain of said feedback amplifier and digging work load.
Claim 22
Independent Claim
90 words
A method of controlling a hydraulic construction machine having a feedback position control system, comprising the steps of: storing an indication of a desired position constraint for an end effector of said construction machine; storing an indication of a desired speed of said end effector; monitoring a working force applied to said end effector; a signal responsive to a position of said end effector being applied through a feedback loop of said feedback position control system; amplifying said signal responsively to results of said step of monitoring a working force.
Claim 23
Independent Claim
90 words
A method of controlling a hydraulic construction machine having a feedback position control system, comprising the steps of: storing an indication of a desired position constraint for an end effector of said construction machine; storing an indication of a desired speed of said end effector; monitoring a working force applied to said end effector; a signal responsive to a position of said end effector being applied through a feedback loop of said feedback position control system; amplifying said signal responsively to results of said step of monitoring a working force.
Claim 24
Dependent Claim
42 words
A method as in claim 18, further comprising the step of amplifying a feedforward signal, responsive to at least one of a stored indication of a desired speed and a stored indication of a desired position constraint, responsively to said working force.
Claim 25
Dependent Claim
23 words
A method as in claim 19, wherein said step of amplifying includes adjusting a gain in response to function stored in a memory.
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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) | 2001-10-26 | 2002-04-27 | 2002-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-26 | 2006-04-27 | 2006-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-26 | 2010-04-27 | 2010-10-27 | $7700.00 | Window Closed / Lapsed |