Auto-calibration of automatic grade control system in a working machine

Patent metadata

Field	Value
Publication number	US-9507348-B2
Application number	US-201615019203-A
Country	US
Kind code	B2
Filing date	Feb 9, 2016
Priority date	Feb 11, 2015
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

A working machine such as a road milling machine of an asphalt paving machine has an automatic grade and slope control system that causes the machine to maintain a pre-selected grade and slope with respect to a reference without significant operator input. A calibration system employs a calibration controller to calibrate the automatic grade and slope control system. The calibration controller causes a current to be sent to a valve that operates a linear actuator that may be employed to change the attitude of the frame of the working machine. The calibration controller uses feedback from at least one sensor, such as a height-measuring sensor or a slope-measuring sensor, in an iterative process that determines the minimum current necessary to cause a change in the attitude of the frame of the working machine. Once this minimum value is determined, the system will establish the optimum settings for the automatic grade and slope control system to improve its efficiency and cause it to operate more smoothly.

First claim

What is claimed is:

1. A calibration system for an automatic attitude control system for a working machine having a frame, a left side linear actuator that is actuated by a left side electrically operated valve for adjusting the attitude of the frame of the machine, and a right side linear actuator that is actuated by a right side electrically operated valve for adjusting the attitude of the frame of the machine, said automatic control system comprising a controller for automatically actuating the left side linear actuator and/or the right side linear actuator of the working machine to maintain a predetermined attitude of the frame, said calibration system comprising:
(a) at least one sensor that is adapted to determine if the actuation of either the left side linear actuator or the right side linear actuator has caused a change in the attitude of the frame of the machine;
(b) a calibrating controller that is:
(i) operatively connected to the at least one sensor;
(ii) operatively connected to the left side electrically operated valve;
(iii) adapted to cause one or more sequential electrical currents to be sent to the left side electrically operated valve, to determine based on input from the at least one sensor if any such electrical current has caused a change in the attitude of the frame of the machine, and to determine a left side sequence count of the number of times that an electrical current that was caused to be sent to the left side electrically operated valve failed to cause a change in the attitude of the frame of the machine;
(iv) adapted to initiate a left side calibration sequence by causing a predetermined minimum electrical current to be sent to the left side electrically operated valve;
(v) adapted to continue the left side calibration sequence, if the previous electrical current sent to the left side electrically operated valve in the left side calibration sequence did not cause a change in the attitude of the frame of the machine, by causing a subsequent electrical current that is larger than the predetermined minimum electrical current by an increment that is equal to a predetermined incremental electrical current value multiplied by the left side sequence count to be sent to the left side electrically operated valve;
(vi) adapted to communicate to the automatic attitude control system a left side electrical current set point equal to the amount of electrical current that was sent to the left side electrically operated valve which was determined by input from the at least one sensor to cause a change in the attitude of the frame of the machine;
(vii) operatively connected to the right side electrically operated valve;
(viii) adapted to cause one or more sequential electrical currents to be sent to the right side electrically operated valve, to determine based on input from the at least one sensor if any such electrical current has caused a change in the attitude of the frame of the machine, and to determine a right side sequence count of the number of times that an electrical current that was caused to be sent to the right side electrically operated valve failed to cause a change in the attitude of the frame of the machine;
(ix) adapted to initiate a right side calibration sequence by causing a predetermined minimum electrical current to be sent to the right side electrically operated valve;
(x) adapted to continue the right side calibration sequence, if the previous electrical current sent to the right side electrically operated valve in the right side calibration sequence did not cause a change in the attitude of the frame of the machine, by causing a subsequent electrical current that is larger than the predetermined minimum electrical current by an increment that is equal to a predetermined incremental electrical current value multiplied by the right side sequence count to be sent to the right side electrically operated valve;
(xi) adapted to communicate to the automatic attitude control system a right side electrical current set point equal to the amount of electrical current that was sent to the right side electrically operated valve which was determined by input from the at least one sensor to cause a change in the attitude of the frame of the machine.

2. The calibration system of claim 1 which is adapted to:
(a) initiate a left side calibration sequence to determine the minimum current necessary to cause the left side linear actuator to change the attitude of the frame of the working machine in the up direction;
(b) initiate a left side calibration sequence to determine the minimum current necessary to cause the left side linear actuator to change the attitude of the frame of the working machine in the down direction;
(c) initiate a right side calibration sequence to determine the minimum current necessary to cause the right side linear actuator to change the attitude of the frame of the working machine in the up direction;
(d) initiate a right side calibration sequence to determine the minimum current necessary to cause the right side linear actuator to change the attitude of the frame of the working machine in the down direction.

3. The calibration system of claim 1 which includes:
(a) a left side switch that is operatively connected to the calibrating controller and adapted to initiate the left side calibration sequence;
(b) a right side switch that is operatively connected to the calibrating controller and adapted to initiate the right side calibration sequence.

4. The calibration system of claim 1 wherein:
(a) the predetermined minimum electrical current that is sent to the left side electrically operated valve in order to initiate a left side calibration sequence is equal to 100 mA;
(b) the predetermined incremental electrical current value that is employed in a left side calibration sequence is 10 mA;
(c) the predetermined minimum electrical current that is sent to the right side electrically operated valve in order to initiate a right side calibration sequence is equal to 100 mA;
(d) the predetermined incremental electrical current value that is employed in a right side calibration sequence is 10 mA.

5. The calibration system of claim 1 wherein:
(a) the left side calibration sequence will continue until:
(i) the calibration controller determines from input from the at least one sensor that electrical current that was sent to the left side electrically operated valve has caused a change in the attitude of the frame of the machine; or
(ii) an electrical current having a value that is equal to a predetermined maximum value is sent to the left side electrically operated valve during the left side calibration sequence and the calibration controller determines from input from the at least one sensor that such electrical current having a predetermined maximum value did not cause a change in the attitude of the frame of the machine;

(b) the right side calibration sequence will continue until:
(i) the calibration controller determines from input from the at least one sensor that electrical current that was sent to the right side electrically operated valve has caused a change in the attitude of the frame of the machine; or
(ii) an electrical current having a value that is equal to a predetermined maximum value is sent to the right side electrically operated valve during the right side calibration sequence and the calibration controller determines from input from the at least one sensor that such electrical current having a predetermined maximum value did not cause a change in the attitude of the frame of the machine.

6. The calibration system of claim 5 wherein:
(a) the predetermined maximum value of electrical current that may be employed in the left side calibration sequence is equal to the predetermined minimum electrical current th

Assignees

• Roadtec Inc

Inventors

• Payne Byron
• Ensell Jeffery A

Classifications

• E01C23/08 Primary

  for roughening or patterning; for removing {the surface down to a predetermined depth} high spots or material bonded to the surface, e.g. markings; {for maintaining earth roads, clay courts or like surfaces by means of surface working tools, e.g. scarifiers, levelling blades}(removing matter not bonded to the surface E01H1/00; roughening or detaching ice E01H5/12) · CPC title

• G05D1/04 Primary

  Control of altitude or depth · CPC title

• E02F9/265

  with follow-up actions (e.g. control signals sent to actuate the work tool) · CPC title

• E02F9/264

  Sensors and their calibration for indicating the position of the work tool · CPC title

• E02F9/2025

  Particular purposes of control systems not otherwise provided for (E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence) · CPC title