Excavating – Ditcher – Condition responsive
Patent
1998-11-10
2000-08-29
Pezzuto, Robert E.
Excavating
Ditcher
Condition responsive
172 2, E02F 920
Patent
active
061089486
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a construction machine such as a hydraulic excavator for excavating the ground, and more particularly to a control method and a control apparatus for a construction machine of the type mentioned.
A construction machine such as a hydraulic excavator has a construction wherein it includes, for example, as schematically shown in FIG. 13, an upper revolving unit 100 with an operator cab (cabin) 600 provided on a lower traveling body 500 having caterpillar members 500A, and further, a joint type arm mechanism composed of a boom 200, a stick 300 and a bucket 400 is provided on the upper revolving unit 100.
And, based on expansion/contraction displacement information of the boom 200, stick 300 and bucket 400 obtained, for example, by stroke sensors 210, 220 and 230, the boom 200, stick 300 and bucket 400 can be driven suitably by hydraulic cylinders 120, 121 and 122, respectively, to perform an excavating operation while the advancing direction of the bucket 400 or the posture of the bucket 400 is kept fixed so that control of the position and the posture of a working member such as the bucket 400 can be performed accurately and stably.
By the way, in such a conventional hydraulic excavator as described above, when an operation (raking) of moving a top of the bucket 400 linearly such as, for example, a horizontal leveling operation is performed automatically by a controller, solenoid valves (control valve mechanisms) in a hydraulic circuit which supplies and discharges working oil to and from the hydraulic cylinders 120, 121 and 122 are electrically feedback controlled to control the expansion/contraction operations of the hydraulic cylinders 120, 121 and 122 to control the postures of the boom 200, stick 300 and bucket 400.
In this instance, the hydraulic cylinders 120, 121 and 122 are connected to the hydraulic circuits and are operated by a delivery pressure from a pump, and when an operator operates an operation lever, supply or discharge of the working oil to or from the hydraulic cylinders 120 to 122 is performed through the hydraulic circuit so that the boom 200, stick 300 and bucket 400 operate.
And, immediately before driving of the joint type arm mechanism is started, the operation lever is disposed in a neutral position (non-driving position), and the pump mentioned above is in a condition (idling condition) wherein it little delivers the working oil. If the operation lever is operated from the condition described, then the delivery pressure of the pump gradually rises in response to the operation amount of the operation lever.
Consequently, immediately after the operation lever is operated from the idling condition of the pump to start automatic control (immediately after driving is started), since the delivery pressure of the pump does not exhibit a sufficient rise, a response delay of the pump occurs, and besides, due to the fact that the pump load is lower than the loads to the hydraulic cylinders 120 to 122, the dead zone is increased, resulting in deterioration of the posture control accuracy of the bucket 400. Accordingly, it is difficult to improve the finish accuracy of a horizontally leveled surface or the like by the bucket 400 immediately after driving is started.
The present invention has been made in view of such a subject as described above, and it is an object of the present invention to provide a control method and a control apparatus for a construction machine by which, even immediately after driving of an arm mechanism is started, a response delay of a pump or an increase of a dead zone is suppressed to achieve improvement in the finish accuracy by a working member.
SUMMARY OF INVENTION
In order to attain the object described above, according to the present invention, a control method for a construction machine wherein a joint type arm mechanism provided on a construction machine body is driven by a cylinder type actuator which is connected to a fluid pressure circuit having a pump, whose delivery pressure is variable in response to an op
REFERENCES:
patent: 5081838 (1992-01-01), Miyaoka et al.
patent: 5092408 (1992-03-01), Tatara et al.
patent: 5477677 (1995-12-01), Krnavek
patent: 5598648 (1997-02-01), Moriya et al.
patent: 5899008 (1999-05-01), Cobo et al.
patent: 5911506 (1999-06-01), Nakamura et al.
Ono Tomoaki
Tozawa Shoji
Pezzuto Robert E.
Shin Caterpillar Mitsubishi Ltd.
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