Automated coupling of an implement to an implement carrier of a power machine

1 . A power machine comprising:

a frame;

a power system supported by the frame;

a traction system supported by the frame and powered by the power system to controllably propel the power machine over a support surface, the traction system including drive motors configured to cause the traction system to move the power machine over the support surface;

an implement interface including an implement carrier configured to receive and secure an implement to the power machine;

a lift arm assembly having at least one lift arm which supports the implement interface;

at least one lift actuator coupled to the lift arm assembly and to the frame and configured to raise and lower the at least one lift arm;

at least one tilt actuator coupled to the implement interface and to the lift arm assembly and configured to rotate the implement carrier relative to the lift arm assembly;

a sensor system configured to provide data indicative of a position of the power machine relative to the implement;

a control system configured to control the traction system to automatically guide the power machine to the implement and to control the power machine to automatically couple the implement to the implement carrier, wherein the control system is configured to control the drive motors, as a function of the position of the power machine relative to the implement as indicated by the data from the sensor system, to automatically guide the power machine to the implement, and wherein the control system is further configured to automatically control the at least one lift actuator to raise or lower the at least one lift arm for automatic coupling of the implement to the implement carrier, and to automatically control the at least one tilt actuator to rotate the implement carrier while automatically coupling the implement to the implement carrier, wherein the control system is configured to determine a desired position state of the power machine and to compare the desired position state to a current position state estimate of the power machine to determine a difference between the current position state estimate and the desired position state, the controller generating a control input, required to move the power machine, as a function of the difference between the current position state estimate and the desired position state.

2 . The power machine of claim 1 , wherein the control system is configured to determine the desired position state of the power machine using the data from the sensor system.

3 . The power machine of claim 1 , wherein the control system is configured to:

generate a current x position of the power machine, a current y position of the power machine, and a current angular position of the power machine relative to an angular position in which the power machine would be positioned for coupling the implement to the implement carrier;

generate a next desired x position of the power machine and a next desired y position of the power machine that move the power machine toward the implement;

calculate a desired angular position as a function of a difference between the desired y position and the current y position and as a function of a difference between the desired x position and the current x position;

calculate a difference between the desired angular position and the current angular position;

determine a desired forward velocity as a function of a difference between the current x position and the desired x position and as a function of a difference between the current y position and the desired y position;

determine a desired rotational velocity as a function of the difference between the desired angular position and the current angular position;

determine whether the difference between the desired angular position and the current angular position is greater than a threshold value;

generate the control input, required to move the power machine, as a function of the desired rotational velocity if the difference between the desired angular position and the current angular position is greater than the threshold value; and

generate the control input, required to move the power machine, as a function of the desired forward velocity if the difference between the desired angular position and the current angular position is less than the threshold value.

4 . The power machine of claim 1 , wherein the control system is a proportional controller.

5 . The power machine of claim 1 , wherein the control system is a point tracking controller.

6 . The power machine of claim 1 , wherein the control system is a proportional integral derivative (PID) controller.

7 . The power machine of claim 1 , wherein the control system is a sequential proportional integral derivative (SPID) controller.

8 . A method of coupling an implement to an implement carrier of a power machine, wherein the power machine comprises a lift arm assembly having at least one lift arm which supports the implement carrier, at least one lift actuator coupled to the lift arm assembly and to a frame and configured to raise and lower the at least one lift arm, and at least one tilt actuator coupled to the implement carrier and to the lift arm assembly and configured to rotate the implement carrier relative to the lift arm assembly, the method comprising:

obtaining data, from a sensor system, indicative of a position of the power machine relative to the implement;

controlling a traction system of the power machine, using a control system and as a function of the data indicative of the position of the power machine relative to the implement, to automatically guide the power machine over a support surface to the implement, wherein the traction system of the power machine further comprises drive motors configured to cause the traction system to move the power machine over the support surface, and wherein controlling the traction system further comprises using the control system to generate a control input, as a function of the position of the power machine relative to the implement as indicated by the data from the sensor system, and controlling the drive motors using the control input to automatically guide the power machine to the implement, wherein using the control system to generate the control input further comprises:

determining a desired position state of the power machine using the data from the sensor system;

comparing the desired position state to a current position state estimate of the power machine to determine a difference between the current position state estimate and the desired position state; and

generating the control input as a function of the difference between the current position state estimate and the desired position state; and

using the control system to automatically control the at least one lift actuator to raise or lower the at least one lift arm for automatic coupling of the implement to the implement carrier and to automatically control the at least one tilt actuator to rotate the implement carrier while automatically coupling the implement to the implement carrier when the power machine is in position proximate the implement.

9 . The method of claim 8 , and further comprising:

generating a current x position of the power machine, a current y position of the power machine, and a current angular position of the power machine relative to an angular position in which the power machine would be positioned for coupling the implement to the implement carrier;

generating a next desired x position of the power machine and a next desired y position of the power machine that move the power machine toward the implement;

calculating a desired angular position as a function of a difference between the desired y position and the current y position and as a function of a difference between the desired x position and the current x position;

calculating a difference between the desired angular position and the current angular position;

determining a desired forward velocity as a function of a difference between the current x position and the desired x position and as a function of a difference between the current y position and the desired y position;

determining a desired rotational velocity as a function of the difference between the desired angular position and the current angular position;

determining whether the difference between the desired angular position and the current angular position is greater than a threshold value;

generating the control input, required to move the power machine, as a function of the desired rotational velocity if the difference between the desired angular position and the current angular position is greater than the threshold value; and

generating the control input, required to move the power machine, as a function of the desired forward velocity if the difference between the desired angular position and the current angular position is less than the threshold value.

10 . The method of claim 8 , wherein using the control system to generate the control input further comprises using a proportional controller to generate the control input.

11 . The method of claim 8 , wherein using the control system to generate the control input further comprises using a point tracking controller to generate the control input.

12 . The method of claim 8 , wherein using the control system to generate the control input further comprises using a proportional integral derivative (PID) controller to generate the control input.

13 . The method of claim 8 , wherein using the control system to generate the control input further comprises using a sequential proportional integral derivative (SPID) controller to generate the control input.