Caterpillar Inc.

Stephen T Tady

Everett Gene Brandt

Brian Daniel Rockwood

Michael L Knussman

Hans P Dietz

Jeffrey Michael Thate

David R Meinhold

Nathan T Schenkel

Brad L Holsapple

William C Evans

Arlyn P Wilcox

An angular velocity control for a boom of a machine is disclosed and a method for controlling the angular velocity of a boom of a machine. The angular velocity control includes a calculator that detects input signals from an operator control lever, a boom angle sensor, a cylinder length sensor, a chassis cant sensor, and a chassis tilt sensor. Movement of the operator control lever allows an operator to pre-select a desired angular velocity. Based on the geometry of the boom to the machine the calculator calculates a boom gain associated with the current boom angle. The calculator then calculates a necessary cylinder velocity to achieve the desired angular velocity. The calculator sends a control signal to an electrohydraulic control module which in turn sends a signal to an electrohydraulic valve associated with a boom lift cylinder. The electrohydraulic valve alters the flow rate of hydraulic fluid into or out of the boom lift cylinder to produce a cylinder velocity that in turn produces the desired angular velocity of the boom.

Angular velocity control and associated method for a boom of a machine

A boom control apparatus and method are disclosed for controlling a boom of a machine. The boom control apparatus includes a boom angle sensor, a boom length sensor, a chassis pitch angle sensor, a chassis roll angle sensor, and a control lever. All of the sensors generate signals associated with the values of their measured parameters. Movement of the control lever along a first axis generates a first pivot velocity signal for a desired pivot velocity of the boom. Movement of the control lever along a second axis generates a first telescoping velocity signal for a desired telescoping velocity of the boom. An electrohydraulic control module detects the signals from the sensors and the control lever. The electrohydraulic control module generates a second pivot velocity signal or a second telescoping velocity signal. The second signals are directly proportional to the first signals and inversely proportional to the signals generated by the sensors. The electrohydraulic control module sends the second signals to an electrohydraulic valve associated either with a boom lift cylinder or a boom telescoping cylinder to effect the desired pivot or telescoping velocity. Thus, the present invention allows for more precise control of the end of a boom when the boom is either extended or elevated.

Boom extension and boom angle control for a machine

A device for controlling an electro-hydraulic differential steering system of a work machine. A first processing device receives a first signal indicative of a desired steering path, a second signal indicative of a ground speed, a third signal indicative of an engine speed, and a fourth signal indicative of a gage. The first processing device transmits a fifth signal as a function of the first, second, third, and fourth signals, the fifth signal being indicative of a desired pump displacement of the steering system. A second processing device receives a sixth signal indicative of a motor speed of the steering system, and the third signal. The second processing device transmits a seventh signal as a function of the third and sixth signals, the seventh signal being indicative of an actual pump displacement of the steering system. A proportional and integral controller is coupled with the first processing device to receive the fifth signal and coupled with the second processing device to receive the seventh signal.

Method and apparatus for controlling an electro-hydraulic differential

A track belt tensioning management system is provided for actively adjusting the tension on a track belt in response to the difference in linear output speed between a drive wheel and the track belt. This is accomplished by sensing the speeds of the drive wheel and the track belt and delivering the sensed signals to a controller which processes the signals and determines the difference in their respective linear output speeds. If the difference varies from a predetermined value, the controller directs appropriate signals to a hydraulic valve arrangement which controllably directs pressurized fluid to and from a hydraulic actuator arrangement to adjust the tension between the drive wheel and the track belt. The subject arrangement maintains sufficient frictional force between the drive wheel and the belt to control the slip therebetween as required while at the same time limiting the forces in order to reduce premature failures and/or wear on the track belt and other associated components.

Track belt tension management system

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DeKalb, IL, United States of America

Stephen T Tady