Caterpillar Inc.

Caterpillar Global Mining LLC

Patrick W Sullivan

Hongliu Du

Andrew J Krajnik

Paul Anthony Dvorak

Edward William Mate

Rex Aaron Glover

Beau Kuipers

Nathanael Garnet McRostie

James Robert Szalko

Justin B Eaton

A machine includes a front section having front wheels, a rear section having rear wheels, and a pivot that couples the front section to the rear section as well as a hydraulic steering circuit that moves the front section relative to the rear section about the pivot. The machine also includes a stabilizer and further includes a directional control valve that selectively depressurizes the hydraulic steering circuit according to a state of the stabilizer.

Articulated machine employing stabilizers and steering interlock

A steering system for a machine is disclosed. The steering system may include a first pilot system including a first pilot source and a first set of electrohydraulic valves, and a second pilot system including a second pilot source and a second set of electrohydraulic valves. The first pilot system and the second pilot system may be configured to move the steering valve via pilot flow of the hydraulic fluid. The steering system may further include an electrohydraulic selector valve configured to regulate pilot flow to the first set of electrohydraulic valves and the second set of electrohydraulic valves. The electrohydraulic selector valve may be a two-position, five-way valve.

Electrohydraulic steering system with diagnostics

A method and apparatus for controlling discharge pressure and pump displacement of a plurality of variable displacement hydraulic pumps having connected discharge ports is provided. Each pump includes a swashplate and a control valve for controlling an angle of inclination of the swashplate. A desired first pump displacement control law is determined for a first pump and determined a desired second pump discharge pressure control law for a second pump. The first control law is used to determine a first intermediate control variable. The second control law is used to determine a second intermediate control variable. The control of the first and second pumps are combined using the first and second intermediate control variables. A desired first control valve setting for the control valve of the first pump is determined using the combined first and second intermediate control variables and the first control law. A desired second control valve setting for the control valve of the second pump is determined using the combined first and second intermediate control variables and the second control law.

Method and apparatus for controlling multiple variable displacement hydraulic pumps

Methods, apparatuses, and computer program products for controlling the torque load of multiple variable displacement hydraulic pumps are described herein. A pump displacement limit for each variable displacement hydraulic pump is determined using a nonlinear control law to limit the total pump torque load of the variable displacement hydraulic pumps on the engine. The value of the actual pump displacement of each variable displacement hydraulic pump is controlled based upon the respective determined pump displacement limit.

Method, apparatus, and computer-readable storage medium for controlling torque load of multiple variable displacement hydraulic pumps

The present disclosure is directed toward a hydraulic control system. The system may have a pump and a tool actuator configured to move a tool with a flow of pressurized fluid provided by the pump. The system may further have a tool control valve configured to control the flow of pressurized fluid to the tool actuator. The system may also have a controller operably connected with the tool control valve and the pump. The controller may be configured to receive a tool movement request. The controller may further be configured to estimate a change in a flow demand across the tool control valve associated with the tool movement request. The controller may also be configured to command adjustment of a discharge flow rate of the pump based on the estimated change in flow demand to satisfy the tool movement request.

Hydraulic control system utilizing feed-forward control

A hydraulic control system for a machine is disclosed. The hydraulic control system may have a pump configured to pressurize fluid, a displacement control valve configured to affect displacement of the pump, and a tool control valve configured to receive pressurized fluid from the pump and to selectively direct to the pressurized fluid to a hydraulic actuator. The hydraulic control system may also have a controller in communication with the displacement control valve. The controller may be configured to determine a pressure gradient across the tool control valve substantially different than a desired pressure gradient, to determine a desired condition of the displacement control valve based the pressure gradient, and to determine a flow force applied to the displacement control valve based on the desired condition. The controller may be further configured to generate a load sense response signal directed to the displacement control valve based on the desired condition and the flow force.

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Tinley Park, IL, United States of America

Patrick W Sullivan