Method and apparatus for determining a spatial positioning of loading equipment

An apparatus, method and sensor apparatus for determining a spatial positioning of loading equipment is disclosed. The loading equipment has an operating implement for loading a payload, the operating implement being coupled to a support for movement relative to the support. The apparatus includes an orientation sensor disposed on the support and being operable to produce an orientation signal representing an orientation of the support. The apparatus also includes a displacement sensor operable to produce a displacement signal representing a displacement of the operating implement relative to the support. The apparatus further includes a processor circuit operably configured to receive the orientation signal and the displacement signal, use a kinematic model of the loading equipment to compute a spatial positioning of the loading equipment, and produce an output signal representing the spatial positioning.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates generally to equipment for loading of a payload and more particularly to an apparatus for determining a spatial positioning of the loading equipment.

2. Description of Related Art

Operation of heavy loading equipment such as electric mining shovels and cranes generally involves an operator controlling the equipment based on visual feedback of the position of an operating implement of the equipment. However, the operator's view of the operating implement and surrounding environment may be constrained by a limited field of view or perspective due to the operator's location in a cab of the loading equipment. For example, in electric mining shovels (also called cable shovels or rope shovels) used for excavating and loading ore using a dipper, the placement of the operator in the cabin is quite removed from the actual operation of the dipper.

Collision between loading equipment and objects or obstacles in the surrounding environment is a serious safety concern, and may also result in damage to the loading equipment. It is also possible that an operator may overload and overstress the operating components of loading equipment by subjecting the equipment to excessive forces, due to a lack of feedback from the controls.

Monitoring systems that sense the spatial positioning of components of the loading equipment on the basis of relative displacement between components have two drawbacks:

(1) They usually require re-initiation from time to time to calibrate the system as they may rely on signals generated by sensors such as potentiometers or resolvers, for example. When the loading equipment is powered down, the calibration information may be lost and the system will require recalibration.

(2) Mining shovels also typically operate in a harsh environment in which there is high likelihood of sensors on the operating components being damaged due to impact or due to ingress of dirt and debris. Systems that rely on signals produced from a plurality of sensors disposed at different locations on key components of the equipment are particularly prone to failure.

There remains a need for improved methods and apparatus of monitoring the spatial positioning of operating implements of loading equipment.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention there is provided an apparatus for determining a spatial positioning of loading equipment, the loading equipment having an operating implement for loading a payload, the operating implement being coupled to a support for movement relative to the support. The apparatus includes an orientation sensor disposed on the support and being operable to produce an orientation signal representing an orientation of the support. The apparatus also includes a displacement sensor operable to produce a displacement signal representing a displacement of the operating implement relative to the support. The apparatus further includes a processor circuit operably configured to receive the orientation signal and the displacement signal, use a kinematic model of the loading equipment to compute a spatial positioning of the loading equipment, and produce an output signal representing the spatial positioning.

The orientation sensor and the displacement sensor may be operable to produce updated orientation and displacement signals during movement of the operating implement and the processor circuit may be operably configured to receive the updated signals and produce an output signal representing a dynamically updated spatial positioning of the loading equipment.

The displacement sensor may be disposed on the support.

The orientation and the displacement sensors may be each disposed within a sensor housing mounted on the support.

The displacement sensor may be disposed on the operating implement.

The orientation signal may include information indicating at least a cardinal heading of the support, and a pitch angle of the support.

The orientation signal may further include a roll angle of the support.

The apparatus may include an interface in communication with the processor circuit and being operably configured to receive coordinates defining a location of the loading equipment with respect to an earth coordinate system, and the processor circuit may be operably configured to use the coordinates and the computed spatial positioning to compute a location of the operating implement with respect to the earth coordinate system.

The loading equipment may include a mining shovel and the processor circuit may be operably configured to correlate the computed location of the operating implement with map data representing a yield expected from ore at the location of the operating implement to provide a yield estimate for the ore loaded in the operating implement.

The interface may be operably configured to receive GPS coordinates defining the location of the loading equipment.

The orientation sensor may include a plurality of sensor elements coupled to a microprocessor circuit, the microprocessor circuit being operably configured to produce the orientation signal in response to receiving signals from the plurality of sensor elements.

The displacement sensor may include a laser rangefinder sensor, the laser rangefinder sensor being operable to direct a laser beam at a target located proximate the operating implement to determine the displacement of the operating implement relative to the support.

The processor circuit may be operably configured to produce the output signal by producing a display signal operable to cause a representation of the loading equipment to be displayed on a display for communicating the spatial positioning to an operator of the loading equipment.

The processor circuit may be operably configured to produce the display signal by producing a display signal operable to cause display of at least one of an elevational representation of the loading equipment indicating the spatial positioning of the loading implement with respect to the loading equipment, and a plan representation of the loading equipment indicating a heading of the operating implement.

The apparatus may include a transmitter operably configured to transmit the output signal to a remote location to facilitate remote monitoring of loading equipment operations.

The transmitter may include a wireless transmitter.

The loading equipment may include a mining shovel having a boom extending outwardly from a frame, the support being pivotably coupled to the boom, the operating implement including a dipper handle having first and second ends, the first end being coupled to a dipper for loading ore from a mine face, the second end being received in the support and being coupled to a drive operable to cause linear reciprocating motion of the dipper handle and dipper with respect to the support, and the displacement sensor is may be operably configured to receive a displacement signal representing a generally linear displacement between the support and the dipper.

The apparatus may include a sensor, disposed on the frame and the processor circuit may be operably configured to receive a signal representing a pitch angle of the frame and a roll angle of the frame, and use the pitch and roll angles of the frame to compute an orientation of the frame prior to computing the spatial positioning of the loading equipment.

The processor circuit may be operably configured to generate a kinematic model of the mining shovel a coupling between a crawler platform where the frame is modeled as a first revolute joint, a coupling between the frame and the boom is modeled as a second revolute joint, a coupling between the boom and the support is modeled as a third revolute joint, and a coupling between the dipper handle and the support is modeled as a prismatic joint.

The dipper may be pivotably coupled to the first end of the dipper handle and may include an adaptor for coupling to a hoist cable, the hoist cable extending over a point sheave disposed at a distal end of the boom, the hoist cable being operable to move the dipper about the first end of the dipper handle and to move the dipper and dipper handle about the support during loading operations, and the processor circuit may be operably configured to compute an orientation and position of the adaptor based on a dipper tip and point sheave locations, compute a length of the hoist cable between the adaptor and the point sheave, compute a rotation of a sheave wheel based on the hoist cable displacement, and produce the output signal by producing an output signal representing an orientation and position of the hoist cable and adaptor.

The spatial positioning signal may be encoded with values representing the orientation and displacement, and the processor circuit may be operably configured to extract the values, and determine compliance of the values with a set of validity criteria prior to using the kinematic model of the loading equipment to compute the spatial positioning of the operating implement.

The processor circuit may be operably configured to compute at least one of a cyclic activity parameter associated with operation of the loading equipment, and a maximum swing angle and frequency associated with a side to side swing of a rotating platform of the loading equipment.

The output signal representing the spatial positioning may be further provided to an image processing system, the image processing system being operably configured to capture and process images of the operating implement to determine at least one of a condition of the operating implement, and a condition of a payload loaded by the operating implement.

In accordance with another aspect of the invention there is provided a method for determining a spatial positioning of loading equipment, the loading equipment having an operating implement for loading a payload, the operating implement being coupled to a support for movement relative to the support. The method involves receiving spatial positioning signals including an orientation signal from an orientation sensor disposed on the support, the orientation signal representing an orientation of the support. The method also involves receiving a displacement signal from a displacement sensor, the displacement signal representing a displacement of the operating implement relative to the support. The method further involves, in response to receiving the spatial positioning signals, using a kinematic model of the loading equipment to compute a spatial positioning of the loading equipment, and producing an output signal representing the spatial positioning.

The orientation sensor and the displacement sensor may be operable to produce updated orientation and displacement signals during movement of the operating implement and receiving the spatial positioning signals may involve receiving the updated signals and producing the output signal may involve producing an output signal representing a dynamically updated spatial positioning of the loading equipment.

Receiving the spatial positioning signals may involve receiving a displacement signal from a displacement sensor disposed on the support.

Receiving the orientation signal and receiving the displacement signal may involve receiving orientation and displacement signals from respective orientation and displacement sensors each disposed in a sensor housing mounted on the support.

Receiving the spatial positioning signals may involve receiving a displacement signal from a displacement sensor disposed on the operating implement.

Receiving the orientation signal may involve receiving a signal including information indicating at least a cardinal heading of the support, and a pitch angle of the support.

Receiving the orientation signal may involve receiving a signal including information indicating a roll angle of the support.

The method may involve receiving coordinates defining a location of the loading equipment with respect to an earth coordinate system, and using the coordinates and the computed spatial positioning to compute a location of the operating implement with respect to the earth coordinate system.

The loading equipment may include a mining shovel and the method may further involve correlating the computed location of the operating implement with map data representing a yield expected from ore at the location of the operating implement to provide a yield estimate for the ore loaded in the operating implement.

Receiving the coordinates may involve receiving GPS coordinates defining the location of the loading equipment.

Receiving the orientation signal from the orientation sensor may involve receiving a signal from a sensor may involve a plurality of sensor elements coupled to a microprocessor, the microprocessor being operably configured to produce the orientation signal in response to receiving signals from the plurality of sensor elements.

Receiving the displacement signal from the displacement sensor may involve receiving a signal from a laser rangefinder sensor, the laser rangefinder sensor being operable to direct a laser beam at a target located proximate the operating implement to determine the displacement of the operating implement relative to the support.

Producing the output signal may involve producing a display signal operable to cause a representation of the loading equipment to be displayed on a display, the representation being operable to communicate the spatial positioning to an operator of the loading equipment.

Producing the display signal may involve producing a display signal operable to cause display of at least one of an elevational representation of the loading equipment indicating the spatial positioning of the loading implement with respect to the loading equipment, and a plan representation of the loading equipment indicating a heading of the operating implement.

The method may involve transmitting the output signal to a remote location to facilitate remote monitoring of loading equipment operations.

Transmitting the output signal may involve wirelessly transmitting the output signal to the remote location.

The loading equipment may include a mining shovel having a boom extending outwardly from a frame, and the support may be pivotably coupled to the boom, the operating implement including a dipper handle having first and second ends, the first end being coupled to a dipper for loading ore from a mine face, the second end being received in the support and being coupled to a drive operable to cause linear reciprocating motion of the dipper handle and dipper with respect to the support, and receiving the displacement signal may involve receiving a signal representing a generally linear displacement between the support and the dipper.

The method may involve receiving a signal representing a pitch angle of the frame and a roll angle of the frame, and using the pitch and roll angles of the frame to compute an orientation of the frame prior to computing the spatial positioning of the loading equipment.

Using the kinematic model of the loading equipment to compute the spatial positioning of the operating implement may involve generating a kinematic model of the mining shovel where a coupling between a crawler platform and the frame may be modeled as a first revolute joint, a coupling between the frame and the boom is modeled as a second revolute joint, a coupling between the boom and the support is modeled as a third revolute joint, and a coupling between the dipper handle and the support is modeled as a prismatic joint.

The dipper may be pivotably coupled to the first end of the dipper handle and may include an adaptor for coupling to a hoist cable, the hoist cable extending over a point sheave disposed at a distal end of the boom, the hoist cable being operable to move the dipper about the first end of the dipper handle and to move the dipper and dipper handle about the support during loading operations, and the method may further involve computing an orientation and position of the adaptor based on a dipper tip and point sheave locations, computing a length of the hoist cable between the adaptor and the point sheave, computing a rotation of a sheave wheel based on the hoist cable displacement, and producing the output signal may involve producing an output signal representing an orientation and position of the hoist cable and adaptor.

Receiving the spatial positioning signals may further involve receiving a spatial positioning signal encoded with values representing the orientation and displacement, extracting the values, and determining compliance of the values with a set of validity criteria prior to using the kinematic model of the loading equipment to compute the spatial positioning of the operating implement.

The method may involve computing at least one of a cyclic activity parameter associated with operation of the loading equipment, and a maximum swing angle and frequency associated with a side to side swing of a rotating platform of the loading equipment.

The method may involve providing the output signal representing the spatial positioning to an image processing system, the image processing system being operably configured to capture and process images of the operating implement to determine at least one of a condition of the operating implement, and a condition of a payload loaded by the operating implement.

In accordance with another aspect of the invention there is provided a sensor apparatus for producing spatial positioning signals for determining a spatial positioning of loading equipment, the loading equipment having an operating implement for loading a payload, the operating implement being coupled to a support for movement relative to the support. The sensor apparatus includes a housing operably configured to be mounted on the support, an orientation sensor and a displacement sensor disposed within the housing and being operably configured to produce spatial positioning signals including an orientation signal representing an orientation of the support, and a displacement signal representing a displacement of the operating implement relative to the support.

The apparatus may include a processor circuit operably configured to receive the spatial positioning signals, to use a kinematic model of the loading equipment to compute a spatial positioning of the operating implement with respect to the loading equipment, and to produce an output signal representing the spatial positioning of the operating implement.

The support may be disposed in a location that is exposed to an environment surrounding the loading equipment and the sensor apparatus may further include a connector port operably configured to receive a cable for conveying the spatial positioning signals to a processor circuit located in an enclosed location on the loading equipment.

DETAILED DESCRIPTION

Referring toFIG. 1, an electric mining shovel is shown generally at100. The mining shovel100includes a frame102pivotably mounted on a crawler platform104. The crawler platform104includes crawler tracks106for moving the mining shovel100to a loading location. The mining shovel100also includes a boom108, pivotably supported on frame102, and an A-frame structure110attached to the frame102. The boom108is supported by a boom suspension cable112. During operation, the boom108is generally maintained at a fixed angle with respect to the frame102. The crawler platform104is configured to permit the frame102and boom108to swing through an arc. Various motors and other equipment (not shown) for operating the mining shovel100are supported by the frame102within an equipment housing114. The frame102further supports a cabin structure116, which houses an operator of the mining shovel and various operating controls for use by the operator.

In this embodiment a dipper118is supported on a dipper handle120. The dipper118acts as an operating implement for the mining shovel. The dipper118and dipper handle120are received in a support122commonly known as a saddle. The support122is pivotably coupled to the boom108and permits the dipper handle120to pivot within a vertical plane about the support. The mining shovel100also includes a crowd mechanism (not shown), which is coupled to the dipper handle120for linearly extending and retracting the dipper118with respect to the support122. The crowd mechanism may be implemented using actuators such as hydraulic cylinders, cables, a rack and pinion drive, or other drive mechanism. The dipper118is suspended by a hoist cable124running over a sheave126disposed at the end of the boom108. The hoist cable124attaches to a dipper adaptor125on the dipper118and is actuated by a winch drive motor (not shown) within the equipment housing114. The hoist cable124and associated drive provides for vertical raising and lowering movement of the dipper118during loading operations.

The mining shovel100includes a sensor apparatus140mounted on the support122. The sensor apparatus140is operable to produce spatial positioning signals for determining a spatial positioning of the mining shovel100. The sensor apparatus140is shown in greater detail inFIG. 2. Referring toFIG. 2, the sensor apparatus140includes a housing142and a mount144for mounting the housing on the support122. The sensor apparatus140also includes an orientation sensor160and a displacement sensor162disposed within the housing142. The sensors160and162are operably configured to produce spatial positioning signals including an orientation signal representing an orientation of the support122, and a displacement signal representing a displacement of the dipper118relative to the support. The sensor apparatus140also includes a connector port146on the rear of the housing142for connecting signal lines for receiving the spatial positioning signals from the sensors160and162and for connecting operating power to the sensors. In other embodiments, the sensor apparatus140may include a wireless interface for transmitting the spatial positioning signals.

In the embodiment shown inFIG. 2, the orientation sensor160is a MEMS (microprocessor-electro-mechanical systems) orientation sensor such as the Xsens MTi manufactured by Xsens, An Enschede, The Netherlands. Other examples of suitable orientation sensors (also called 3DOT sensors) that may be used in this application are the 3DM-GX2 from MicroStrain Inc of Williston, Vt., USA, the InertiaCube 2+ from InterSense Incorporated of Billerica Mass., USA, and the Liberty electromagnetic tracker from Polhemous of Colchester, Vt., USA.

Referring toFIG. 3, the Xsens MTi sensor160includes a housing202and a mounting base204that defines a right handed Cartesian co-ordinate system206for the sensor. The housing202of the sensor160encloses a temperature sensor, three accelerometers respectively aligned to the X, Y, and Z axes206for measuring linear accelerations (sensitive to the earth's gravitational field), three magnetometers for measuring the earth's magnetic fields to determine a cardinal direction with respect to the earth's magnetic field, and three rate gyroscopes for measuring a rate of rotation about the X, Y, and Z axes.

The sensor160further includes signal conditioning amplifiers to condition signals produced by the various included sensors, analog to digital converters, and a dedicated digital signal processor (DSP), disposed within the housing202. The DSP receives the various signals generated by the gyroscopes, magnetometers and accelerometers and uses a proprietary algorithm to process the signals, apply various corrections and calibration factors, and generate a 3D heading and attitude of the sensor160. The static accuracy of the generated heading is considered to be less than 1° and the static accuracy of the attitude less than 0.5°. The DSP encodes the generated 3D attitude and heading into a data stream and produces a data signal output at a port208. The produced data signal may be compliant with a data signalling protocol such as RS-323, RS-485, RS-422, or USB. Configuration commands may also be transmitted to the DSP via the port208, using the data signalling protocol. Power for operating the DSP and the various sensor elements is also connected to the sensor160though the port208. In the sensor apparatus140shown inFIG. 2, power and signal lines of the port208of the orientation sensor160are connected to the connector port146of the sensor apparatus140. Advantageously, the orientation sensor160provides an accurate 3D heading and attitude of the housing142of the sensor apparatus140in any of a variety of signal formats. The orientation sensor160is also fully enclosed within the housing202, which provides protection for sensor elements when operating in a harsh environment such as a mine. In other embodiments, the MEMS based orientation sensor may be substituted by other sensors that provide heading and attitude. For example, a biaxial accelerometer may be used to produce orientation signals representing the attitude of the support122, and the signals may be filtered using a low pass filter to remove high frequency variations in the signal. A compass type sensor may be used to provide a heading signal.

In the embodiment shown inFIG. 2, the displacement sensor162comprises a laser rangefinder such as the Acuity AR4000 system manufactured by Schmitt Industries of Portland, Oreg., USA. Other examples of suitable rangefinder sensors that may be used in this application are the DT500 from Sick AG, Waldkirch, Germany, the LDM 42 from Jenoptik AG of Jena, Germany, the LLD sensor from Waycon Positionsmesstechnik, Taufkirchen, Germany, and the DLS-BH from Dimetix, of Herisau, Switzerland. The aforementioned rangefinder sensors are examples of non-contact laser rangefinders. It is however also possible to use other absolute linear displacement sensors such as a magnetostriction linear-position sensor for example. An example of a magnetostriction sensor is the Temposonic® linear position sensor, produced by MTS Systems Corporation of Cary, N.C., USA, which provides a dynamic reading of absolute displacement at an accuracy of 0.01″.

Referring toFIG. 4, the laser rangefinder displacement sensor162includes a sensor housing232having a data port236and data cable238for carrying data signals to and from the displacement sensor162. The displacement sensor162receives electrical operating power via a power cable234. The housing232also includes a window240. A laser diode (not shown) is disposed to direct a collimated beam of light through the window240toward a target. In this embodiment the target is located on the dipper118and a surface finish of the dipper may provide for sufficient reflection to act as the target. In other embodiments a reflective element may be disposed on the dipper to provide an enhanced reflection, or alternatively the displacement sensor162may be disposed on the dipper handle120and configured to measure a distance between the sensor and the support122. The laser diode may have a visible or infrared wavelength. Light reflected back from the target is collected by a Fresnel collection lens and directed to an avalanche detector located within the housing232.

The displacement sensor162also includes a processor circuit (not shown) that implements a modified time-of-flight measurement principle for processing the return signal from the avalanche detector to generate a displacement signal. The displacement signal provides an absolute measurement of the displacement between the housing232and the target. The processor circuit encodes the displacement into a data stream and produces a data signal output at the data port236, which may be compliant with a data signalling protocol such as RS-323, RS-485, or RS-422.

Referring back toFIG. 2, the housing142also includes a turret148. The housing142further includes a window150that allows the light beam to be transmitted, while protecting the sensors160and162and interior of the housing from egress of water and contaminants. In one embodiment the window150comprises a lexan-sapphire window material. The turret148extends outwardly to protect the window from falling debris or dirt.

Advantageously, the orientation signal and displacement signal provide continuous real-time information during normal operation of the mining shovel100, and it is not necessary to stop operating the dipper118to sense the disposition of the dipper or other operating implement. Furthermore there is no need to move the dipper118or dipper handle120to a reference spatial position to calibrate the sensors, since the orientation signal is referenced to the earth's magnetic and gravitational field.

Referring toFIG. 5, a block diagram of an apparatus for determining a spatial positioning of loading equipment, such as the electric mining shovel, is shown generally at250. The apparatus250includes the sensor apparatus140shown inFIG. 2, and further includes a processor circuit300. The processor circuit300is coupled by a cable166to the connector port146of the sensor apparatus140for receiving the orientation signal and the displacement signal. The processor circuit300is further configured to use a kinematic model of the loading equipment to compute an orientation and a position of the dipper118and dipper handle120of the electric mining shovel. The apparatus250further includes a display252in communication with the processor circuit300, which is operably configured to produce an output signal representing the orientation and the position of the dipper118and dipper handle120.

In a mining shovel embodiment, the processor circuit300would most likely be located in the cabin116, and the cable166would be routed along the boom108to between the sensor apparatus140and the cabin. Advantageously, in the embodiment shown inFIG. 1, while the sensor apparatus140would necessarily be exposed to an environment surrounding the mining shovel100, the processor circuit300is located within the cabin116(or in the equipment housing114) thereby reducing the likelihood of damage.

The sensor apparatus140is mounted on the saddle block or support122with the X-axis206of the orientation sensor160aligned along the boom108, such that the orientation signal received from the sensor apparatus140provides a heading of the boom with respect to the ground. The orientation signal received from the sensor apparatus140also provides the attitude (i.e. the pitch, roll, and yaw angles of the support122thereby providing the attitude of the dipper handle120, which is coupled to the support.

The light beam produced by the displacement sensor162is reflected back to the sensor apparatus140from the dipper118, and the displacement signal produced by the sensor apparatus thus provides the location of the dipper with respect to the sensor apparatus140. In the electric shovel embodiment shown inFIG. 1, the boom108is generally maintained at a substantially fixed angle and the attitude and heading of the saddle support122and the extension of the dipper118, along with geometric configuration details of the mining shovel components, provides sufficient information to facilitate computation of the spatial positioning of the dipper handle120, boom108, cabin116, and frame102, as detailed later herein. Alternatively, in other embodiments where the support is mounted on a boom that is not disposed at a fixed angle, or where it is desired to account for small angular movements due to compliance of the boom suspension cable112, an additional orientation sensor may be disposed on the boom to determine the actual boom angle with respect to the cabin. The additional orientation sensor may be a single axis orientation sensor or a 3D orientation sensor such as the sensor160.

The processor circuit300is shown in greater detail inFIG. 6. Referring toFIG. 6, the processor circuit300includes a microprocessor302, a program memory304, a variable memory306, a media reader308, and an input output port (I/O)310, all of which are in communication with the microprocessor302.

Program codes for directing the microprocessor302to carry out various functions are stored in the program memory304, which may be implemented as a compact flash memory or other memory such as a random access memory, hard disk drive, or a combination thereof. The program memory304includes a first block of program codes320for directing the microprocessor302to perform operating system functions. In one embodiment the program codes320may implement the Windows Embedded operating system, produced by Microsoft Corporation of Redmond, Wash., USA. The program memory304also includes a second block of program codes322for directing the microprocessor302to perform functions associated with determining the spatial positioning of the mining shovel100.

The media reader308facilitates loading program codes into the program memory304from a computer readable medium312, such as a CD ROM disk314, or a computer readable signal316, such as may be received over a network, for example.

The I/O310includes a first input330for receiving an orientation signal from the orientation sensor160and a second input332for receiving the displacement signal from the displacement sensor162. The I/O310also includes a third input334for receiving a cab orientation signal and a fourth input336for receiving a GPS location signal. The cab orientation signal and GPS location signals are described later herein. The I/O310further includes a first output340for producing a display signal for controlling the display252and a second output342for producing a signal for controlling a wireless transmitter350.

The variable memory306includes a plurality of storage locations including a memory store360for storing an attitude value, a memory store362for storing a heading value, a memory store364for storing a displacement value, a memory store366for storing current data set values, a memory store368for storing kinematic model parameter values, a memory store370for storing computed spatial positioning data values, a memory store372for storing graphic images of shovel components, and a memory store374for storing a historic data log. The variable memory306may be implemented in random access memory, for example.

Referring toFIG. 7, a flowchart depicting blocks of code for directing the processor circuit300to determine the spatial positioning of the mining shovel100is shown generally at400. The blocks generally represent codes that may be read from the computer readable medium312, and stored as program codes322in the program memory304, for directing the microprocessor302to perform various functions related to determining spatial positioning. The actual code to implement each block may be written in any suitable program language, such as C, C++ and/or assembly code, for example.

The process begins at block402, which directs the microprocessor302to receive the spatial positioning signals from the sensor, including the orientation signal and the displacement signal. In one embodiment the spatial positioning signals are received from the orientation sensor160and displacement sensor162at a regular update interval and, block402directs the microprocessor302to decode the orientation signal to generate attitude and heading values and to store the values in the respective memory stores360and362of the variable memory306(shown inFIG. 6). In this embodiment, the orientation sensor160uses the magnetometers to determine a magnetic north direction with respect to the earth's magnetic field. The internal DSP in the orientation sensor160also determines the pitch, roll, and yaw of the mounting base204of the sensor160. The Yaw angle, expressed relative to magnetic north, provides a compass heading of the sensor and thus the saddle support122and dipper handle120. This yaw angle is saved as the heading (i.e. θ1) in the heading memory store362. The pitch angle generated by orientation sensor160provides the attitude of the mounting base204of the sensor160, and thus the attitude of the support122and dipper arm120. The pitch angle is saved in the attitude memory store360.

Block402also directs the microprocessor302to decode the displacement signal to generate a displacement value d and to store the displacement value in the memory store364of the variable memory306.

Block404then directs the microprocessor302to process and validate the values stored in the memory stores360-364. For example, the values may be compared to criteria such as maximum and minimum values expected based on the geometry of the mining shovel100and values that do not meet the criteria, or values that result from a false sensor reading, for example, will be discarded.

The process400then continues at block406, which directs the microprocessor302to retrieve current values of attitude, heading, and displacement from the memory stores360-364and to store the values as a data set in the memory store366of the variable memory306. The memory stores360-364thus act as containers for receiving values streamed from the sensors160and162, while the memory store366is used to store a validated set of values representing the orientation of the support122and the displacement of the dipper118at a particular time.

Block408then directs the microprocessor302to read parameters associated with a kinematic model of the mining shovel100from the memory store368of the variable memory306and to compute the spatial positioning of the loading equipment using the kinematic model. The process400then continues at block410, which directs the microprocessor302to produce an output signal representing the computed spatial positioning.

The process of block408shown inFIG. 7for computing the spatial positioning of the electric mining shovel100is shown in greater detail at408inFIG. 8. Referring toFIG. 8, the process408begins at block440, which directs the microprocessor302to read the kinematic model parameters from the memory store368of the variable memory306(shown inFIG. 6).

In one embodiment, the mining shovel100may be modeled using the Denavit-Hartenberg method, which provides a convention for selecting frames of reference in robotics applications. Referring back toFIG. 1, the mining shovel100may be treated as a 4 degree of freedom (DOF) manipulator having three revolute joints and one prismatic joint. The three revolute joints include a joint152between the crawler platform104and the cabin that permits the cabin to swing about the crawler platform (angle θ1), a joint154between the frame102and the boom108(i.e. angle θ2), and a joint156between the saddle support122and the boom (i.e. angle θ3) that allows the saddle to pivot to accommodate raising or lowering of the dipper118. In this embodiment the boom joint angle θ2is taken into account as a fixed angle. In other embodiments, the boom joint angle may be taken into consideration as a variable angle, since in operation the boom108may undergo small angular displacement about the boom joint154due to the compliance of the suspension cable, particularly when the dipper118is fully loaded. Furthermore, in some circumstances the boom108may pivot upwardly when the dipper118engages the mine face and the dipper and dipper handle120continue to move away from the boom. When the dipper118is subsequently retracted by the operator, the boom may come down with an impact against the boom suspension cable112. This condition is referred to as boom jacking, and may be accounted for by inclusion of a further boom angle sensor as described earlier herein.

The prismatic joint comprises a joint158between the dipper handle120and the saddle support122and takes into account an extension d of the dipper handle with respect to the support122due to operation of the crowd mechanism.

The mining shovel100shown inFIG. 1may be represented by a simplified model shown inFIG. 9at500where the ground is represented by a plane502and where the joints152-158are respectively defined by respective xyz Cartesian coordinate frames o0, o1, o2and o3. The operating implement (in this case the dipper118) is represented by a frame o4inFIG. 9. The Denavit-Hartenberg parameters of the mining shovel100are shown in tabular form inFIG. 10at520, where θ1-θ3and d4are the joint angular and linear displacements as discussed above, a1is the link length between o0and o1, a2is the link length between o1and o2, and a3is the link length between o2and o3. The angles α1-α4are angular offsets of the respective z-axes (z0-z4) in moving between the respective coordinate frames at the joints o0-o3and frame o4.

The boom108is included as a link in the simplified model500, and its connection to the frame102is defined as a passive joint o1, since in this embodiment the boom joint is considered fixed.

The parameters in the table ofFIG. 10are stored in the memory store368of the variable memory306. As noted above, block440directs the microprocessor302to read the parameters from the memory store368.

The process then continues at block442, which directs the microprocessor302to compute the orientation of the cabin116(i.e. θ1) and the resulting position of the boom joint154. Since the boom108is aligned with the cabin116, block442directs the microprocessor302to read the yaw angle value stored in the memory store366of the variable memory306, which is used as the angle θ1. The boom joint (o1) position with respect to the joint152(o0) is then determined from the angle θ1and the link length a2. In this embodiment it is assumed that the cabin116and frame102are horizontally oriented with respect to the ground, but in other embodiments the cabin pitch and roll orientations may be provided by a 3-axis accelerometer, such as the CXL-GP accelerometer produced by Crossbow Technology, Inc. of San Jose, Calif., USA, or by a roll/pitch sensor provided by the same company, or an Xsens MTi sensor, as described above. When provided, such a sensor provides an orientation of the frame102, which, since the boom118is attached to the frame, will have some influence on the spatial positioning of the shovel when the cabin is not horizontally oriented.

Block444then directs the microprocessor302to read the boom joint angle θ2, which in the embodiments above is considered to be fixed, but may be sensed by a high resolution joint angle sensor, as described above. Block444further directs the microprocessor302to compute the position of the joint156(o2) using the angle θ2and the link length a2.

Block446then directs the microprocessor to compute the position and orientation of the joint158(03) of the saddle support122. Block446directs the microprocessor302to read the pitch angle of the saddle support122from the memory store366of the variable memory306, which provides the angle θ3. Block446further directs the microprocessor302to compute the position of the joint o3from the angle θ3and the link length a3. The orientation of the prismatic joint o3provides the orientation of the dipper handle120, which in this embodiment is assumed to be rigidly coupled for substantially linear extension and retraction with respect to the support.

The process then continues at block448, which directs the microprocessor302to read the measured displacement d4from the memory store366of the variable memory306and to compute the resulting position of the dipper118(i.e. the frame o4) using the angle θ3and the displacement d4.

In another embodiment, the Denavit-Hartenberg model parameters may be used to generate a transform matrix, which may be used to simultaneously execute the blocks442-448shown inFIG. 8.

Considering the mining shovel100represented inFIG. 1as a series of links, with a frame rigidly attached to each link, the location and orientation of the bucket or the end-effecter (frame o4) may be expressed with respect to the base frame o0as:
T04=A01(θ1)A12(θ2)A23(θ3)A34(d4)  Eqn 1

The transformation matrix TO4is a transformation matrix from the dipper118to the crawler platform104, where:

In other embodiments the process440shown inFIG. 8may include further steps for computing the orientation and position of the hoist cable124. Block450directs the microprocessor302to compute the position of the sheave126, which is provided by the boom angle θ2and a known spacing between the joint o1and the sheave. The computed position of the dipper118also facilitates determination of the dipper adaptor125, thus allowing computation of the orientation of the hoist cable124.

The process440then continues at block450, which directs the microprocessor301to store the computed data defining the spatial positioning of the components of the mining shovel100in the memory store370of the variable memory306.

The process of block410shown inFIG. 7for producing display signals for displaying a representation of the electric mining shovel100is shown in greater detail inFIG. 11. An exemplary representation of the mining shovel100produced by the processor circuit300on the display252is shown at550inFIG. 12. Referring toFIG. 11, the process410begins at block480, which directs the microprocessor302to read the computed data defining the spatial positioning of the components of the mining shovel100from the memory store370. Block482then directs the microprocessor302to read graphic images of a first shovel component from the variable memory306. Each major component of the mining shovel such as crawler platform104, frame102and cabin116, boom108, saddle support122, dipper handle120and dipper118may have an associated graphic image that may be used to generate a representation of the mining shovel100in the correct spatial positioning.

Block484then directs the microprocessor302to position the first graphic image in space. In this embodiment the crawler platform104is used as a reference and thus does not require any change of spatial positioning and is displayed as shown inFIG. 12. Referring toFIG. 12, the representation550includes an elevational view552of the mining shovel100and a plan view554of the shovel. In the embodiment shown, the orientation of the crawler tracks is not computed and a crawler platform representation556is shown in a default horizontal orientation.

Referring back toFIG. 11, the process then continues at block486, which directs the microprocessor302to determine whether further graphic images remain to be displayed, in which case the process continues at block488. Block488directs the microprocessor302to read the next graphic image from the memory372. Block488then directs the microprocessor302to repeat blocks484and486for the next graphic image, which in this embodiment would be the frame and the cabin of the mining shovel100. Referring toFIG. 12, the cabin and frame are shown at558, and the image representation is rotated in the plan view554to show the heading of the cabin relative to the crawler platform, which is not clearly visible in the plan view representation554.

Blocks484and486are then repeated for the remaining graphic images of the boom560, saddle support562, dipper handle564, dipper566, and hoist cable568, as shown inFIG. 12. If at block486, it is determined that the last graphic images has been processed, block486directs the microprocessor302to block490. Block490directs the microprocessor302to cause the I/O310(shown inFIG. 6) to output a display signal at the first output340for displaying the resultant mining shovel representation image550on the display252. Advantageously, the representation inFIG. 12provides an operator of the mining shovel100with a real time display of the spatial positioning of the various components of the shovel that forms useful feedback for operations.

The representation550also provides a data logging control panel570that facilitates input by the operator to start logging shovel data. When a start button572is activated by the operator (for example by touching a touch sensitive area of the display252), the spatial positioning data in the memory store370is copied to the data log memory store374in the variable memory306. The memory store370thus accumulates subsequent updated spatial positioning data associated with operation of the mining shovel100, thus providing a historic record of shovel operations over time. The historic record may be used to analyze performance of the mining shovel and/or operator. For example, loading operations that result in excessive cabin swing about the crawler platform to a particular side may result in preferential wear to components and may be discerned by examining swing angle data in the historic record. Analysis may also be performed to determine other performance indicators such as non-digging time, or a cyclic activity parameter associated with operation of the loading equipment, for example. Advantageously, the historic record may provide a useful indication of mining shovel performance and performance of specific operators assigned to operate the shovel.

In a further embodiment, the microprocessor302may be further configured to cause the I/O310to output a data signal encoding the data set values stored in the memory store366or the historic data374at the second output342for transmission to a remote location by the wireless transmitter350. In one embodiment, the remote location may be a dispatch center associated with mine operations, and the transmission may be used to provide data for monitoring operations of the mining shovel100.

In the embodiments described above, while spatial positioning is determined with respect to magnetic north, the exact location of the mining shovel100is not available. Referring back toFIG. 6, in an alternative embodiment, the mining shovel100may be equipped with GPS receiver, and a GPS location signal may be received at the fourth input336of the I/O310. The GPS location signal provides a real time absolute location of the mining shovel frame o0(shown inFIG. 9), and may be used by the microprocessor302to compute respective absolute locations of the shovel components, such as the dipper118. For loading equipment that does not have a GPS receiver, the orientation sensor160may be replaced by a sensor that has an integrated GPS receiver and provides GPS location in addition to the attitude and heading. Advantageously, accurately sensing an absolute location of an operating implement (such as the dipper118) by combining GPS sensor signals and spatial positioning information provided by the apparatus250is particularly useful in mining of minerals such as precious metals (for example gold and platinum). Knowledge of a precise digging location may be correlated with the geological map of the mine to determine a percentage yield of ore being loaded by the dipper118, thus facilitating efficient mining of ore from the mine.

Advantageously, the apparatus250disclosed above determines a real-time spatial positioning of the dipper118with respect to the crawler platform104of the mining shovel100. The determined spatial position of the dipper118may be used by other systems for monitoring operations of the mining shovel100. For example, Motion Metrics International Corp of Vancouver, BC, Canada provides the ToothMetrics™ and WearMetrics™ systems for monitoring a condition of the dipper teeth that engage the mine face during digging operations and are prone to wear and damage, as well as the FragMetrics™ system that provides information of the condition of the payload. These systems operate on the basis of views of the dipper captured by camera. Accordingly, prior knowledge of the spatial positioning or posture of the dipper handle120and dipper118reduces image processing required to locate the dipper and determine the spatial positioning of the dipper in the image. The spatial positioning information provided by the apparatus250may be used to confirm the orientation of the dipper handle120and dipper118and/or to reduce the processing necessary to locate these components in the captured images.

While the embodiments have been described in connection with the mining shovel100shown inFIG. 1, the sensor apparatus140and processor circuit300may be implemented on other loading equipment such as various types of cranes, mining shovels, and other heavy machinery where collective movement of specific components is necessary for the safe and efficient operation of the machinery. Accordingly, various aspects of the invention may be implemented in equipment used in quarries, construction, and oil industries, for example.

An example of a telescopic crane is shown inFIG. 13at580. The crane580includes a telescopic boom582that is configured to pivot about a support584. A sensor apparatus, such as the sensor apparatus140shown inFIG. 2may be mounted on the boom582of the crane580to provide both an orientation of the boom and a distance d to the end of the boom, which corresponds to the extended length of the boom. A display in an operating cabin of the crane580may be configured to display a representation of the crane in a similar manner to that described above in connection with the representation shown inFIG. 12at550.

An example of a tower crane is shown inFIG. 14at590. The crane590includes a boom or horizontal jib592and a trolley594configured to travel along the jib. The trolley includes a sheave for guiding a lifting cable596that supports a hook block598. A sensor apparatus may be mounted on the jib592to provide both an orientation of the jib and a distance d to the trolley594. As in the telescopic crane example above, a display in an operating cabin of the crane590may be configured to display a representation of the crane590.

Advantageously, the above embodiments provide absolute orientation information associated with working components of the loading apparatus on which the sensor apparatus is installed. Furthermore, orientation information is provided by sensors housed in a common housing, such as the housing142shown inFIG. 2, thus simplifying mounting and installation of the sensor apparatus.