Caterpillar Inc.

Other

University of Illinois

Xiaodong Huang

John James Krone

Rabie E Khalil

Brad Allen Edler

Mark L Westphalen

Yongmin Ma

Brent M Carr

Stephen V Lunzman

Michael J Mientus

Bradford Jay Holt

Kirk S Shively

Luke F Lester

Sairam Gopalan Velamakanni

Kevin J Malloy

Sabri Cetinkunt

Julian Cheng

Guangtian Liu

Andreas Stintz

A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Steering system having multiple strategies and variable deadzone

A method of steering a vehicle with a hydraulic steering system is disclosed. A first control signal is sent to a pilot valve. The pilot valve is operated to direct pilot fluid to a main valve in response to the first control signal. The main valve is opened to a first position in response to the pilot fluid. Fluid is directed through the main valve to a first actuator. Resistance to actuation of the first actuator is detected. The detected resistance is compared to a threshold resistance. A second control signal is sent to the pilot valve when the detected resistance exceeds the threshold resistance. The pilot valve is operated to direct pilot fluid to the main valve in response to the second control signal. The main valve is opened to a second position in response to the pilot fluid. Fluid is directed through the main valve to the first actuator and a second actuator.

On-demand electro-hydraulic steering system

A hydraulic steering system for a work machine may include a first steering actuator having a first and a second chamber. In addition, the steering system may include a second steering actuator having a third and a fourth chamber. A multi-position directional valve may include at least one low power position and at least one high power position. The low power position may be configured to direct fluid only to the first chamber during a low power turn to extend the first steering actuator. The high power position may be configured to direct fluid to the first chamber and the third chamber during a high power turn to retract the second steering actuator.

An electro-hydraulic system for a machine may include a brake charging system including at least one accumulator. A fan drive system may include a fan and a fan motor. A fluid source may be in communication with the brake charging system and the fan drive system. The fluid source may be configured to provide pressurized fluid to the brake charging system and the fan drive system to charge at least one accumulator and to drive a fan motor. A priority valve may be configured to provide pressure from the fluid source to the brake charging system, such that the fluid pressure at the accumulator is maintained at a substantially constant level during normal operating conditions.

Electro-hydraulic system for fan driving and brake charging

An electro-hydraulic steering control system for directing fluid to steering actuators on a work machine may include a main valve configured to control fluid flow to the steering actuators. Left and right primary steering valves may be in communication with and configured to affect the main valve to control fluid flow to the steering actuators. Left and right redundant steering valves may be in communication with and configured to affect the main valve to control fluid flow to the steering actuators. A shuttle valve may be operably disposed between one of the right primary and the right redundant steering valves and the left primary and left redundant steering valves. The shuttle valve may be operable to selectively control fluid from the one of the right primary and the right redundant steering valves and the left primary and left redundant steering valves to the main valve to control the main valve.

Electro-hydraulic steering control system

An operator input device includes an operator interface mechanism operable by an operator, a position sensor, a brake controller, and a resistive actuator. The operator interface mechanism is moveable in at least first and second directions along an axis. The position sensor is coupled to the operator interface mechanism for transmitting an operator interface mechanism position signal as a function of the position of the operator interface mechanism. The brake controller is coupled to the position sensor for receiving the operator interface mechanism position signal and responsively transmitting a brake signal. The resistive actuator is coupled to the brake controller and the operator interface mechanism and receives the brake signal and responsively applies a resistive force to the operator interface mechanism.

Operator input device with tactile feedback

A quantum dot vertical cavity surface-emitting laser has a low threshold gain. Top and bottom mirrors have a low mirror loss, with at least one of the mirrors being laterally oxidized to form semiconductor/oxide mirror pairs. In one embodiment, mode control layers reduce the optical field intensity in contact layers, reducing optical absorption. In one embodiment, delamination features are included to inhibit the tendency of laterally oxidized mirrors from delaminating.

Quantum dot vertical cavity surface emitting laser

A system and method for controlling an electro-hydraulic valve arrangement to perform a pump check function are provided. The system includes an electro-hydraulic valve arrangement disposed between a source of pressurized fluid and a hydraulic actuator. Pressure sensors are provided to sense a source pressure representative of the fluid pressure between the source of pressurized fluid and the electro-hydraulic valve arrangement and an actuator pressure representative of the fluid pressure between the electro-hydraulic valve arrangement and the actuator. A control device receives a signal to open the electro-hydraulic valve arrangement to provide a requested flow rate to the hydraulic actuator. The received signal is modified to prevent fluid flow through the electro-hydraulic valve arrangement when the source pressure is less than the actuator pressure.

Electro-hydraulic valve control system and method

A system and method for controlling an electro-hydraulic valve arrangement to provide make-up fluid to a hydraulic actuator are disclosed. The system includes an electro-hydraulic valve arrangement actuated by a control lever and disposed between a pump having a stand-by pressure and a hydraulic actuator. A pressure, representative of the fluid in the hydraulic actuator, is sensed and compared to the stand-by pressure of the pump. The control of the control lever over the electro-hydraulic valve arrangement is overridden when the difference between the pump stand-by pressure and the pressure of the fluid in the hydraulic actuator is greater than a predetermined pressure limit.

Growing community of inventors

Peoria, IL, United States of America

Xiaodong Huang