Method for position-calibration of a digging assembly for electric mining shovels

• US 8,515,708 B2
• Filed: 03/31/2009
• Issued: 08/20/2013
• Est. Priority Date: 04/01/2008
• Status: Active Grant

• Current Assignee: Ezymine Pty., Limited
• Original Assignee: CMTE Development Limited
• Inventors: Reid, Anthony Walton, Austin, Kevin John, Siegrist, Paul Martin, McAree, Peter Ross
• Primary Examiner(s): KUNDU, SUJOY K
• Application Number:
  US12/935,529
• Publication Number:
  US 20110029279A1
• Time in Patent Office: 1,603 Days
• Field of Search: 702/150, 701/50
• US Class Current: 702/150
• CPC Class Codes: E02F 3/435 for dipper-arms, backhoes or the like
• CPC Class Codes: E02F 3/47 with grab buckets grab equipment for cranes B66C
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool
• CPC Class Codes: G01B 21/04 by measuring coordinates of points

Abstract

The present invention relates generally to the field of positioning mechanical equipment, and particularly to the likes of mechanical excavation and electric mining shovels. In one embodiment, there is disclosed a system for calibrating the sensors that measure hoist and crowd motions for an electric mining shovel, enabling the position of a bucket to be known with greater accuracy than can be achieved using previously known approaches.

Claims

1. A method of calibrating a work implement location, the work implement being attached to a machine house, the method comprising the steps of

(a) defining a h-frame comprising a set of Cartesian coordinate axes fixed to the machine house with the (X, Z) plane being in the sagittal plane of the machine house and the Y-axis being orthogonal;

(b) utilising a range measurement sensor at a point p_h=(x_h,z_h) in the h-frame to create a directed line of measurement in the (X_h,Z_h)-plane of the h-frame originating at p_h along which a range measurement is made, designated by angle θ

_h;

(c) defining a d-frame comprising a set of Cartesian coordinate axes fixed to the work implement;

(d) providing a range measurement sensor target at a point p_d=(x_d,z_d) in the d-frame on the work implement;

(e) measuring a Cartesian distance d between p_h and p_d; and

(f) measuring corresponding positions of motors used to drive the work implement.

2. A method as claimed in claim 1 wherein said work implement comprises a shovel handle and dipper assembly.

3. A method as claimed in claim 2 wherein the digging assembly is attached to a hoist and crowd motor and said method further comprises correlating the distance d with the measured position of the hoist motor, d_hm and the crowd motor d_cm for different distances d.

4. A method as claimed in claim 1 comprising the step of:

(g) maneuvering the work implement so that the range measurement sensor target intersects the line of measurement,

wherein step (g) occurs prior to step (e).

5. A method as claimed in claim 3 wherein the digging assembly includes a crowd actuator and a hoist actuator which are driven by the crowd motor and the hoist motor respectively, thereby to drive the work implement.

6. A method as claimed in claim 5 comprising the step of:

(h) computing calibration offsets, o_c and o_h, for the crowd and hoist actuators.

7. A method as claimed in claim 6, wherein step (h) comprises the steps of:

(i) computing the extension of the crowd actuator d_c and the saddle angle θ

_x, which together define the position and orientation of the d-frame relative to the h-frame; and

(j) thereafter computing the extension of the hoist actuator d_h.

8. A method as claimed in claim 7, wherein step (h) comprises the further step of:

(k) utilising the computed actuator extensions d_c and d_h, and the measured motor positions d_hm and d_cm to calculate the calibration offsets o_c and o_h.

9. A method as claimed in claim 8, comprising the step of utilising an independent range measurement sensor directed along a line to resolve the crowd and hoist offsets o_c and o_h.

10. A system for allowing the calibration of a work implement location, the work implement being attached to a machine house, the system comprising:

(a) a component for defining an h-frame comprising a set of Cartesian coordinate axes fixed to the machine house with the (X, Z) plane being in the sagittal plane of the machine house and the Y-axis being orthogonal;

(b) a component for utilising a range measurement sensor at a point p_h=(x_h,z_h) in the h-frame to create a directed line of measurement in the (X_h,Z_h)-plane of the h-frame originating at p_h along which a range measurement is made, designated by angle θ

_h;

a component for defining a d-frame comprising a set of Cartesian coordinate axes fixed to the work implement;

(d) a component for providing a range measurement sensor target at point p_d=(x_d,z_d) in the d-frame on the work implement;

(e) a component for measuring a Cartesian distance between p_h and p_d; and

(f) a component for measuring corresponding positions of motors used to drive the work implement.