System and method for positioning a lift arm on a power machine

Patent metadata

Field	Value
Publication number	US-9951494-B2
Application number	US-201615142991-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Apr 29, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A method of controlling a lift arm actuator and a tilt actuator to control positioning of an implement carrier coupled to a lift arm of a power machine. An activation signal is received from an enabling input device. A lift arm control signal is received from a lift arm control input commanding movement of the lift arm. The lift arm actuator is controlled responsive to receipt of both of the activation signal and the lift arm control signal to move the lift arm to a target lift arm position and to move the implement carrier to or maintain the implement carrier at a target implement carrier orientation relative to a gravitational direction.

First claim

What is claimed is:

1. A method of controlling a lift arm actuator and a tilt actuator to control positioning of an implement carrier coupled to a lift arm of a power machine, the method comprising:
receiving an activation signal from an enabling input device;
receiving a lift arm control signal from a lift arm control input commanding movement of the lift arm; and
using a controller, controlling the lift arm actuator and the tilt actuator responsive to receipt of both of the activation signal and the lift arm control signal to move the lift arm to a predefined target lift arm position and to move the implement carrier to or maintain the implement carrier at a target implement carrier orientation relative to a gravitational direction.

2. The method of claim 1 , and further comprising receiving a tilt control signal indicative of a position of a tilt control input, wherein controlling the lift arm actuator and the tilt actuator responsive to receipt of both of the activation signal and the lift arm control signal further comprises:
determining whether the tilt control signal is indicative of a neutral or non-neutral position of the tilt control input; and
maintaining the target implement carrier orientation relative to the gravitational direction, when the lift arm control signal from the lift arm control input commands movement of the lift arm and the tilt control input is in the neutral position, by controlling the lift arm actuator in response to the lift arm control signal to move the lift arm and by controlling the tilt actuator to maintain the target implement carrier orientation relative to the gravitational direction while the lift arm is moving.

3. The method of claim 2 , wherein controlling the lift arm actuator and the tilt actuator further comprises moving the tilt actuator when the tilt control signal indicates that the tilt control input is not in the neutral position and responsively changing the target implement carrier orientation.

4. The method of claim 2 , wherein controlling the lift arm actuator and the tilt actuator further comprises:
determining whether a pressure sensor signal is indicative of a pressure above a threshold pressure; and
controlling the lift arm actuator in response to the lift arm control signal to move the lift arm; and
controlling the tilt actuator to maintain the target implement carrier orientation relative to the gravitational direction while the tilt control input is in the neutral position and the lift arm is moving if the pressure sensor signal is not indicative of the pressure being above the threshold pressure, and if the pressure signal is indicative of the pressure being above the threshold pressure, stopping actuation of the tilt actuator.

5. The method of claim 1 , wherein controlling the lift arm actuator and the tilt actuator further comprises:
controlling speed of movement of the lift arm based upon the lift arm control signal from the lift arm control input.

6. The method of claim 1 , and further comprising:
receiving a position set signal from a position set input device; and
setting the predefined target lift arm position and the target implement carrier orientation responsive to the position set signal.

7. The method of claim 6 wherein the predefined target lift arm position is a first predefined target lift arm position, and further comprising setting a second predefined target lift arm.

8. The method of claim 7 , and further comprising controlling a speed at which the lift arm actuator moves the lift arm toward one of the first and the second predefined target lift arm positions based upon an amount of actuation of the lift arm control input.

9. The method of claim 7 , and wherein the lift arm control signal includes a direction component corresponding to a direction of actuation of the lift arm control input commanding the lift arm to be one of raised and lowered, wherein controlling the lift arm actuator responsive to receipt of both of the activation signal and the lift arm control signal to move the lift arm includes identifying one of the first and second predefined target lift arm positions based upon the direction component and moving the lift arm towards the identified one of the first and second predefined target lift arm positions.

10. A power machine comprising:
a frame;
a lift arm pivotably coupled to the frame;
a lift arm actuator coupled between the frame and the lift arm to control movement of the lift arm relative to the frame;
an implement carrier pivotably coupled to the lift arm;
a tilt actuator coupled between the lift arm and the implement carrier to control movement of the implement carrier relative to the lift arm;
a power source in communication with each of the lift arm actuator and the tilt actuator and configured to provide power source control signals to control the lift arm actuator and the tilt actuator;
an enabling input device configured to be manipulated by a power machine operator to provide an activation signal;
a lift arm control input configured to be manipulated by the power machine operator to provide a lift arm control signal;
a tilt control input configured to be manipulated by the power machine operator to provide a tilt control signal;
an implement orientation sensor configured to provide an output indicative of an orientation of the implement relative to a gravitational direction; and
a controller coupled to the enabling input device to receive the activation signal, to the lift arm control input to receive the lift arm control signal, to the tilt control input to receive the tilt control signal, and to the implement orientation sensor to receive the output indicative of the orientation of the implement relative to the gravitational direction, the controller further coupled to the power source to control the power source control signals and thereby control the lift arm actuator and the tilt actuator;
wherein the controller is further configured to control the lift arm actuator and the tilt actuator responsive to receipt of both of the activation signal and the lift arm control signal to move the lift arm to a predefined target lift arm position and to move the implement carrier to or maintain the implement carrier at a target implement carrier orientation relative to a gravitational direction.

11. The power machine of claim 10 , wherein the controller is further configured to control the lift arm actuator and the tilt actuator by:
determining whether the tilt control signal is indicative of a neutral or non-neutral position of the tilt control input; and
maintaining the target implement carrier orientation relative to the gravitational direction, when the lift arm control signal commands movement of the lift arm and the tilt control input is in the neutral position, by controlling the lift arm actuator in response to the lift arm control signal to move the lift arm and by controlling the tilt actuator to maintain the target implement carrier orientation relative to the gravitational direction while the lift arm is moving.

12. The power machine of claim 11 , wherein the controller is further configured to control the lift arm actuator and the tilt actuator by moving the tilt actuator when the tilt control input is not in the neutral position and responsively changing the target implement carrier orientation.

13. The power machine of claim 12 , and further comprising a pressure sensor configured to provide a pressure sensor signal indicative of a pressure in at least one of the power source and the tilt actuator, wherein the controller is further configured to control the lift arm actuator and the tilt actuator by:
determining w

Assignees

• Clark Equipment Co

Inventors

• Zent Kevin J
• Krause Trevor W
• Roehrl Jonathan J
• Carpenter Marty

Classifications

• E02F3/435 Primary

  for dipper-arms, backhoes or the like · CPC title

• E02F9/2041

  Automatic repositioning of implements, i.e. memorising determined positions of the implement (for dipper-arms or bucket-arms E02F3/434, E02F3/437, E02F3/438, E02F3/439 take precedence) · CPC title

• E02F3/432 Primary

  for keeping the bucket in a predetermined position or attitude · CPC title

• E02F3/436

  for keeping the dipper in the horizontal position, e.g. self-levelling · CPC title

• E02F3/30

  with a dipper-arm pivoted on a cantilever beam {, i.e. boom} · CPC title