LOW POWER CONTROL SYSTEM FOR AN ELEVATED WORK PLATFORM

• US 20130313042A1
• Filed: 03/15/2013
• Published: 11/28/2013
• Est. Priority Date: 05/23/2012
• Status: Active Grant

• Current Assignee: Altec Industries Incorporated (Avon Protection Plc)
• Original Assignee: Altec Industries Incorporated (Avon Protection Plc)
• Inventors: Freeman, Michael Jon, Mueller, Joshua Daniel, Maag, Allen Leon, Ross, David Lavern, Greer, Mark D.
• Granted Patent: US 9,527,713 B2
• Time in Patent Office: Days
• US Class Current: 182/19
• CPC Class Codes: B66F 11/044 Working platforms suspended from booms

Abstract

A control system optimized for low-power operation includes an electronic valve controller for controlling a hydraulic valve and a control interface for receiving operating commands from a user and communicating the operating commands to the electronic valve controller. The control interface includes a multi-function single hand control with a plurality of position indicating elements for detecting actuation of the single hand control, a master enable associated with all of the position indicating elements, and a plurality of individual enable elements each associated with one of the position indicating elements. A controller directs operation of the control interface and is configured to sample a position indicating element only if the master enable is asserted and the corresponding individual enable element is asserted. Other aspects of the control system minimize power consumption, including fast sampling that allows the controller to spend more time in a low power mode.

Claims

1. A control system including an electrically isolated control interface, the control system comprising:

an electronic valve controller for controlling a hydraulic valve;

a control interface for receiving operating commands from a user and communicating the operating commands to the electronic valve controller, the control interface including—

a multi-function single hand control with a plurality of position indicating elements for detecting actuation of the single hand control,

a master enable associated with all of the position indicating elements, and

a plurality of individual enable elements each associated with one of the position indicating elements; and

a controller for controlling operation of the control interface, the controller configured to sample a position indicating element only if the master enable is asserted and the corresponding individual enable element is asserted.

2. The system of claim 1, each of the position indicating elements including a potentiometer.

3. The system of claim 2, each of the potentiometers having a maximum impedance of between 200Ω

and 10 kΩ

.

4. The system of claim 3, the control interface further including a capacitor configured to energize one of the potentiometers when the controller samples the potentiometer.

5. The system of claim 4, the control interface further including a high impedance circuit configured to charge the capacitor, the high impedance circuit having an impedance of at least 500 kΩ

.

6. The system of claim 4, the controller being configured to sample each of the potentiometers to determine the position of the potentiometer by applying a voltage to the potentiometer from the capacitor and measuring the voltage at the wiper of the potentiometer.

7. The system of claim 6, the controller being configured to sample each potentiometer in less than five microseconds.

8. The system of claim 4, the controller further configured to—

identify a fault in a position indicating element if the voltage on the capacitor after applying the voltage is below a predetermined lower threshold level or above a predetermined upper threshold level, and

prevent sampling of that position indicating element after a fault is detected.

9. The system of claim 1, the electronic valve controller including a receiver for receiving a signal from the control interface, the receiver including a gain function and being configured to automatically adjust the gain so that the output of the gain function remains constant as the strength of the received signal fluctuates.

10. The system of claim 1, the electronic valve controller configured to confirm that a control signal received from the control interface includes valid signal values, and to disable the hydraulic valve if the control signal includes one or more invalid signal values.

11. The system of claim 1, the controller configured to—

operate in a normal operating mode, wherein the controller periodically reads the master enable and, if the master enable is asserted, samples any of the position indicating elements if the corresponding individual enable is asserted,

operate in a low power mode if the master enable is not asserted for a predetermined amount of time, wherein the controller reads the master enable less frequently than in the normal operating mode, and

return to normal operating mode when it samples one of the position indicating elements.

12. The system of claim 1, further comprising a fiber optic communications link or a wireless communications link for communicating control signals from the control interface to the electronic valve controller.

13. A system comprising:

an electronic valve controller for controlling a hydraulic valve;

a control interface for receiving operating commands from a user and communicating the operating commands to the electronic valve controller through a fiber optic communications link, the control interface including—

a multi-function single hand control with a plurality of potentiometer circuits for detecting actuation of the single hand control, each of the potentiometer circuits including a low impedance potentiometer, and utilizing a capacitor for energizing the potentiometer during sampling operations, and a high impedance circuit for charging the capacitor,

a master enable associated with all of the potentiometer circuits, the master enable being physically actuated by an operator, and

a plurality of individual enable elements each associated with one of the potentiometer circuits, each of the individual enable elements being physically actuated by movement of the single hand control; and

a controller for controlling operation of the control interface, the controller configured to sample a potentiometer circuit only if the master enable is asserted and the corresponding individual enable element is asserted.

14. The system of claim 13, the controller configured to determine the number of high bits and the number of low bits in an information packet communicated from the control interface to the electronic valve controller and to invert all of the bits if the number of high bits exceeds the number of low bits.

15. The system of claim 13, each of the potentiometers having a maximum impedance less than 10 kΩ

, and each of the high impedance circuits having an impedance of at least 500 kΩ

.

16. The system of claim 13, the controller being configured to sample each of the potentiometers to determine the position of the potentiometer by applying a voltage to the potentiometer from the respective capacitor and measuring the voltage at the wiper of the potentiometer, wherein the controller is configured to sample each potentiometer in less than five microseconds.

17. The system of claim 16, the controller further configured to—

identify a fault in a potentiometer circuit if the voltage of the corresponding capacitor after applying the voltage is below a predetermined lower threshold level or above a predetermined upper threshold level, and

prevent sampling of that potentiometer circuit after a fault is detected.

18. The system of claim 13,

wherein the electronic valve controller includes a receiver for receiving a signal from the control interface, the receiver including a gain function and being configured to automatically adjust the gain so that the output of the gain function remains constant as the strength of the received signal fluctuates, and

wherein the electronic valve controller is configured to confirm that a control signal received from the control interface includes valid signal values, and to disable the hydraulic valve if the control signal includes one or more invalid signal values.

19. The system of claim 13, the controller further configured to—

operate in a normal operating mode, wherein the controller periodically reads the master enable to determine whether it is asserted and, if the master enable is asserted, samples any of the potentiometer circuits if the corresponding individual enable is asserted,

operate in a low power mode if the master enable is not asserted for a predetermined amount of time, wherein the controller reads the master enable less frequently than in the normal operating mode, and

return to normal operating mode when it samples one of the potentiometer circuits.

20. An elevated work platform comprising:

a boom supported by a vehicle chassis;

a platform supported by a portion of the boom distal the chassis;

a hydraulic control valve proximate the chassis for controlling operation of the boom;

an electronic valve controller for controlling a hydraulic valve;

a control interface located at the platform for receiving operating commands from a user and communicating the operating commands to the electronic valve controller, the control interface including—

a multi-function single hand control with a plurality of position indicating elements for detecting actuation of the single hand control,

a master enable associated with all of the position indicating elements, and

a plurality of individual enable elements each associated with one of the position indicating elements; and

a controller for controlling operation of the control interface, the controller configured to sample a position indicating element only if the master enable is asserted and the corresponding individual enable element is asserted.

21. The elevated work platform as set forth in claim 20, the controller configured to automatically direct electronic valve controller to disable a hydraulic tools function of the hydraulic control valve upon detecting a user command to actuate the boom.