Features of main control computer for a power machine

• US 6,785,596 B2
• Filed: 12/27/2000
• Issued: 08/31/2004
• Est. Priority Date: 04/23/1999
• Status: Expired due to Term

• Current Assignee: Clark Equipment Company (Doosan Enerbility Company Limited)
• Original Assignee: Clark Equipment Company (Doosan Enerbility Company Limited)
• Inventors: Rossow, Scott R., Brandt, Kenneth A.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/749,356
• Publication Number:
  US 20010007087A1
• Time in Patent Office: 1,343 Days
• Field of Search: 701/50, 701/53, 184/6.1, 372/34, 745/015.H, 172/812, 172/263, 172/260.5, 298/22.C, 702/114, 137/883, 137/861, 604/84, 604/20, 604/27
• US Class Current: 701/50
• CPC Class Codes: E02F 3/3414 the arms being pivoted at the rear of the vehicle chassis, e.g. skid steer loader
• CPC Class Codes: E02F 3/431 for bucket-arms, front-end loaders, dumpers or the like
• CPC Class Codes: E02F 9/2029 Controlling the position of implements in function of its load, e.g. modifying the attitude of implements in accordance to vehicle speed control for hydraulic or pneumatic drives E02F9/2203, E02F9/2221 and E02F9/2253 take precedence
• CPC Class Codes: E02F 9/2062 Control of propulsion units for control of the prime mover depending on the load in a hydraulic or pneumatic drive E02F9/2246
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/226 Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
• CPC Class Codes: E02F 9/2267 Valves or distributors position of valves arrangements on upper-structures E02F9/0875
• CPC Class Codes: E02F 9/2271 Actuators and supports therefor and protection therefor
• CPC Class Codes: E02F 9/24 Safety devices , e.g. for preventing overload E02F9/226 takes precedence
• CPC Class Codes: E02F 9/26 Indicating devices E02F5/145 takes precedence
• CPC Class Codes: F01P 2025/08 Temperature
• CPC Class Codes: F01P 2025/40 Oil temperature
• CPC Class Codes: F01P 7/044 using hydraulic drives
• CPC Class Codes: F02D 2200/023 Temperature of lubricating oil or working fluid
• CPC Class Codes: F02D 41/083 taking into account engine load variation, e.g. air-conditionning
• CPC Class Codes: F15B 21/087 Control strategy, e.g. with block diagram
• CPC Class Codes: Y10T 137/86614 Electric
• CPC Class Codes: Y10T 74/20414 Hydraulic control

Abstract

The present invention is directed to a computer based control system for controlling hydraulic and electromechanical actuators on a power machine, such as a skid steer loader. The computer based control system is configured to implement a number of features to enhance certain operational aspects of the power machine.

Claims

1. A power machine control system for a power machine having an engine, a hydraulic power system providing hydraulic fluid under pressure, and a hydraulic actuator, the control system comprising:

an engine speed sensor for sensing a speed of the engine;

a proportionally controllable valve controllably coupling the hydraulic fluid under pressure to the hydraulic actuator; and

a controller coupled to the engine speed sensor and the valve, providing a modulated control signal to the valve and configured to vary the modulated control signal based on engine speed, wherein the modulated control signal has a variable duty cycle and wherein the controller is configured to vary the duty cycle based on the sensed engine speed.

2. The control system of claim 1, wherein the controller includes an associated memory storing a plurality of duty cycle profiles corresponding to a plurality of engine speeds and wherein the controller is configured to access the memory and provide the modulated control signal based on a duty cycle profile accessed in response to the sensed engine speed.

3. A power machine control system for a power machine having an engine, a traction system coupled to the engine to move the power machine, a hydraulic power system providing hydraulic fluid under pressure, the control system comprising:

a user actuable speed select input providing a speed select signal indicative of a request to operate at a selected one of a plurality of speeds, the speed being determined based on a position of a hydraulic speed valve providing hydraulic fluid under pressure to the traction system;

a controller coupled to the speed select input and providing a modulated output signal to operably control the speed valve to transition from a first position associated with a first speed to a second position associated with the selected speed, based on the speed select signal.

4. The control system of claim 3 wherein the controller includes associated memory storing a speed modulation profile and wherein the controller is configured to provide the modulated output signal according to the speed modulation profile.

5. The control system of claim 4 wherein the memory stores a plurality of speed modulation profiles each used by the controller under predetermined operating conditions.

6. The control system of claim 3 wherein the controller is configured to provide the modulated output signal to control movement of the speed valve from the first to the second position at a first speed during a first portion of the transition and at a second speed during a second portion of the transition.

7. The control system of claim 6 wherein the first speed is greater than the second speed.

8. The control system of claim 3 wherein the controller is configured to provide the modulated output signal to control movement of the speed valve from the first to the second position at a substantially constant rate of speed.