Tracking rotation with swing sensors

Abstract

A system and method for tracking the orientation of an excavator includes: obtaining an initial orientation of the excavator platform; and associating a current orientation of the excavator platform with the initial orientation. The system includes obtaining coordinates of a measurement center of a GNSS device. The coordinates of a center of rotation of the excavator platform are determined using the initial orientation of the excavator platform, the coordinates of the measurement center, and a known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform. The rotation of the excavator platform is tracked from the initial orientation to a first orientation using rotation measurements from a swing sensor.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Non-Provisional Application No. 16 / 688,635, entitled "Tracking Rotation With a Swing Sensor," filed on November 19, 2019, the entire contents of which are incorporated herein by reference.

[0002]

[0002] Embodiments described herein relate generally to tracking rotation with a swing sensor, and more particularly to using rotation measurements from a swing sensor to determine coordinates of a center of rotation of a rotating platform, such as the excavator platform of an excavator, which may be used, for example, to estimate a bucket tip position when excavating. [Background technology]

[0003]

[0003] It is often useful to track the rotation of a platform, such as an excavator platform. As used herein, an excavator refers broadly to any type of construction machine that includes a rotating platform. The rotating platform generally rests on a chassis that includes tracks or wheels. Some types of construction machines include a bucket or other implement coupled to the rotating platform by an arm (e.g., a boom and / or stick). Rotation measurements can be used to determine the coordinates of the center of rotation of the rotating platform, which can be used to determine the position of the bucket or other implement in space. This information is useful, for example, when excavating.

[0004]

[0004] Conventional techniques for determining the coordinates of the center of rotation include taking several position measurements during a platform rotation and fitting a circular arc to the measurements. This technique often requires the platform to rotate up to 100° or more to provide a good curve for fitting. As an example, assuming a position measurement rate of 10 Hz, a swing of about 100° in 4 seconds will provide 40 data points for curve fitting. When the platform moves from one position to another, the initialization process, which requires large rotations, must be repeated to determine the coordinates of the center of rotation at the new position.

[0005] In light of the above, an improved method for determining the coordinates of the center of rotation of a rotating platform is desired. Summary of the Invention

[0006]

[0006] The embodiments described herein provide improved systems and methods for tracking platform rotation and / or determining the coordinates of the platform's center of rotation. As used herein, the rotation of the platform is about a vertical axis of rotation, and the center of rotation of the platform is at the intersection of the vertical axis of rotation and the horizontal axis of rotation.

[0007]

[0007] A swing sensor is coupled to the excavator and configured to measure rotation of the excavator platform about a vertical axis of rotation. The vertical axis is aligned with the center of rotation. Using rotation measurements from the swing sensor and position measurements from a single Global Navigation Satellite System (GNSS) device, the coordinates of the platform's center of rotation can be determined. Although reference is made herein to a GNSS device, it should be understood that other measurement devices providing the same or similar position information can also be used with the described embodiments.

[0008]

[0008] According to a particular embodiment, a system for tracking an orientation of an excavator includes an excavator platform coupled to an undercarriage of the excavator along a vertical axis aligned with a center of rotation of the excavator platform. The excavator platform is configured to rotate about the vertical axis, and the undercarriage is configured to support the excavator platform and effectuate translational movement of the excavator platform. A single GNSS device is coupled to the excavator platform having a measurement center located away from the vertical axis aligned with the center of rotation of the excavator platform. The measurement center is arranged in a known spatial relationship with the center of rotation of the excavator platform. The GNSS device is configured to determine coordinates of the measurement center in a real world coordinate system. A swing sensor is coupled to the excavator and configured to measure rotation of the excavator platform about the vertical axis aligned with the center of rotation. A controller is communicatively coupled to the GNSS device and the swing sensor. The controller is configured to obtain an initial orientation of the excavator platform, associate a current orientation of the excavator platform with the initial orientation, obtain a coordinate of a measurement center from the GNSS device, and determine a coordinate of a center of rotation of the excavator platform using the initial orientation of the excavator platform, the coordinate of the measurement center, and a known spatial relationship between the measurement center of the GNSS device and a center of rotation of the excavator platform. The controller is also configured to track a rotation of the excavator platform from the initial orientation to the first orientation using rotation measurements from the swing sensor.

[0009] In one embodiment, the swing sensor is coupled to the excavator platform or undercarriage at a location proximate to the rotation point between the excavator platform and the undercarriage.

[0010]

[0010] In another embodiment, the controller is configured to obtain an initial orientation of the excavator platform by obtaining multiple coordinates of the measurement center of the GNSS device while rotating the excavator platform, and to determine the initial orientation of the excavator platform using the multiple coordinates.

[0011]

[0011] In another embodiment, the controller is further configured to track the translational movement of the excavator while it is traveling using coordinate measurements from the GNSS device, and the controller is also configured to track the rotation of the excavator platform while it is traveling using rotation measurements from the swing sensor.

[0012] In another embodiment, the controller is further configured to determine a second coordinate of a center of rotation of the excavator platform after navigating the excavator from the first location to the second location and after rotating the excavator platform from the first orientation to the second orientation, the second coordinate of the center of rotation being determined using coordinate measurements of the GNSS device at the second location and rotation measurements from the swing sensor during rotation from the first orientation to the second orientation.

[0013]

[0013] In another embodiment, the excavator platform is coupled to an excavator arm including a work implement, and the controller is further configured to determine the coordinates of the work implement's blade in the real world coordinate system using the coordinates of the excavator platform's center of rotation.

[0014] In yet another embodiment, the swing sensor is configured to measure rotation of the excavator platform by measuring angular displacement of the excavator platform about a vertical axis aligned with the center of rotation.

[0015]

[0015] According to another embodiment, a method for tracking an orientation of an excavator using a single GNSS device and a swing sensor includes obtaining an initial orientation of an excavator platform of an excavator and correlating a current orientation of the excavator platform with the initial orientation. A first coordinate of a measurement center of the GNSS device is obtained. The measurement center of the GNSS device is located away from a vertical axis aligned with a center of rotation of the excavator platform, and the measurement center of the GNSS device is arranged in a known spatial relationship with the center of rotation of the excavator platform. The first coordinate of the excavator platform's center of rotation is determined using the initial orientation of the excavator platform, the first coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform. Rotation of the excavator platform is tracked from the initial orientation to the first orientation using rotation measurements from the swing sensor. The swing sensor is arranged proximate a rotation point between the excavator platform and an excavator chassis and configured to measure rotation of the excavator platform about a vertical axis aligned with the center of rotation. The excavator is navigated from a first location to a second location, and while the excavator is traversed, translational movement of the excavator is tracked using position measurements from the GNSS device and rotation of the excavator platform is tracked from a first orientation to a second orientation using rotational measurements from the swing sensor. After traversing the excavator, a second coordinate of a measurement centre of the GNSS device is obtained and a second coordinate of a center of rotation of the excavator platform is determined using the second orientation, the second coordinate of the measurement centre of the GNSS device and the known spatial relationship between the measurement centre of the GNSS device and the center of rotation of the excavator platform.

[0016]

[0016] In one embodiment, the step of obtaining an initial orientation of the excavator platform includes a step of obtaining multiple coordinates of the measurement center of the GNSS device while translating the excavator, and a step of determining an initial orientation of the excavator platform using the multiple coordinates.

[0017]

[0017] In another embodiment, the method also includes tracking rotation of the excavator platform from the second orientation to a third orientation after running the excavator using only rotation measurements from the swing sensor, without obtaining orientation information from any source other than the swing sensor, and without performing an orientation initialization procedure after running.

[0018] In another embodiment, an initial orientation of the excavator platform is obtained in a real world coordinate system and a second position of the excavator is determined in the real world coordinate system.

[0019]

[0019] In another embodiment, the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform includes the distance between the measurement center of the GNSS device and the center of rotation along at least one axis in the coordinate system of the excavator platform.

[0020]

[0020] In yet another embodiment, the excavator platform is coupled to an excavator arm including a work machine, and the method also includes determining coordinates of a blade of the work machine in the real world coordinate system using coordinates of a center of rotation of the excavator platform.

[0021] According to yet another embodiment, a method for tracking an orientation of an excavator using a GNSS device and a swing sensor includes obtaining a first orientation of an excavator platform of the excavator, correlating a current orientation of the excavator platform with the first orientation, and obtaining a first coordinate of a measurement center of the GNSS device. The measurement center of the GNSS device is located away from a vertical axis aligned with a center of rotation of the excavator platform, and the measurement center of the GNSS device is arranged in a known spatial relationship with the center of rotation of the excavator platform. The first coordinate of the excavator platform's center of rotation is determined using the first orientation of the excavator platform, the first coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform. The excavator travels from a first location to a second location, and during the travel of the excavator, a translational movement of the excavator is tracked using the GNSS device and a rotational measurement from the swing sensor is tracked to track a rotation of the excavator platform from the first orientation to the second orientation. The swing sensor is configured to measure a rotation of the excavator platform about a vertical axis aligned with the center of rotation. After running the excavator, a second coordinate of the measurement center of the GNSS device and a second coordinate of the center of rotation of the excavator platform are determined using the second orientation of the excavator platform, the second coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform.

[0022]

[0022] Using the embodiments described herein, many advantages are achieved over the prior art. For example, some embodiments allow for direct measurement of rotation rather than calculation based on other sensor measurements. This can improve accuracy and eliminate drift in rotation information. Some embodiments can track rotation during and after a run without obtaining orientation information from any source other than the swing sensor and without performing an orientation initialization procedure after a run. In excavator applications, efficiency can be improved since multiple separate orientation initialization steps are not required. These and other advantages are described throughout this specification with reference to the accompanying drawings. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a simplified side view of an excavator that can be used with some of the embodiments described herein. [Figure 2A] 4 is a flowchart illustrating an exemplary method for determining the coordinates of a center of rotation of an excavator platform and tracking the orientation of the excavator platform, according to some embodiments. [Figure 2B] 5 is another flowchart illustrating an exemplary method for determining a coordinate of a center of rotation of an excavator platform and tracking an orientation of the excavator platform, according to some embodiments. [Figure 2C] 5 is yet another flowchart illustrating an exemplary method for determining a coordinate of a center of rotation of an excavator platform and tracking an orientation of the excavator platform, according to some embodiments. [Diagram 3] FIG. 1 is a simplified block diagram of an exemplary system for tracking the orientation of an excavator, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024]

[0026] The embodiments described herein provide improved systems and methods for tracking platform rotation and / or determining the coordinates of the platform's center of rotation using a swing sensor. The rotation measurements obtained by the swing sensor can be used to track the rotation of the platform before, during, and after translational movement of the platform. The rotation measurements can be used in conjunction with position measurements to determine the coordinates of the center of rotation.

[0025]

[0027] A real world example of a platform used throughout this application is an excavator having a rotating excavator platform coupled to an undercarriage that includes movable tracks or wheels. It should be understood that an excavator is used herein merely as an example, and the described embodiments can be used with any other equipment, vehicle, machine, or device that includes a rotating platform coupled to an undercarriage. When used with an excavator, the acquired information can be used in accordance with known techniques to determine the position of a bucket or implement in a real world coordinate system.

[0026]

[0028] FIG. 1 is a simplified side view of an excavator that can be used with some of the embodiments described herein. The excavator includes an excavator platform 11 and a chassis 32. The excavator platform 11 is configured to rotate about a vertical axis of rotation 35 using a hydraulic motor or by other means. The vertical axis of rotation 35 is aligned with a center of rotation 14 of the excavator platform 11. The center of rotation 14 is at the intersection of the vertical axis of rotation 35, a horizontal axis of rotation 36, and a horizontal axis of rotation that extends perpendicular to the drawing plane of FIG. 1. The center of rotation 14 is an origin for tracking the position of a blade of an implement, such as the teeth 30 of a bucket 20. It should be understood that the excavator can be used with other implements or tools other than the bucket 20, such as an auger, a trencher, a compactor, etc.

[0027]

[0029] The undercarriage 32 is configured to support the excavator platform 11 and in this example includes tracks that provide translational movement of the excavator platform 11. The excavator platform 11 is coupled to the undercarriage 32 at a point of rotation between the excavator platform 11 and the undercarriage 32. As an example, the excavator platform 11 may be coupled to the undercarriage 32 by a rotary union that rotates 360° about a vertical axis of rotation 35.

[0028]

[0030] The excavator of this example also has a boom 12, a stick 16, and a bucket 20. The boom 12 is pivotally connected to the platform 11 at a pivot point (not shown), the stick 16 is pivotally connected to the boom 12 at a pivot point 18, and the bucket 20 is pivotally connected to the stick 16 at a pivot point 22. Hydraulic devices 24, 26, 28 are provided for moving the boom 12, the stick 16, and the bucket 20.

[0029]

[0031] Excavators typically utilize various sensors to monitor the position of various machine elements and / or provide an indication of element position to an operator. The excavator of this example also has a swing sensor 33. The swing sensor 33 is configured to measure the rotation of the excavator platform 11 about a vertical axis of rotation 35. The swing sensor 33 can measure the rotation of the excavator platform 11 by measuring the angular displacement of the excavator platform 11 about the vertical axis of rotation 35. The swing sensor 33 may be located at or near a rotation point between the excavator platform 11 and the undercarriage 32. The swing sensor 33 may be any type of sensor that provides a direct measurement of rotation. Examples include optical sensors and magnetic sensors such as Hall effect sensors.

[0030]

[0032] The excavator also includes a single GNSS device 34. The GNSS device 34 is positioned on the platform 11 at a location away from the centre of rotation 14 such that the measured position of the GNSS device 34 changes as the platform 11 rotates. The GNSS device 34 is arranged in a known spatial relationship to the centre of rotation 14. For example, the GNSS device 34 may be arranged at a known position in the coordinate system of the platform 11.

[0031]

[0033] It should be understood that the antenna of the GNSS device 34 may be located separately from the receiver of the GNSS device 34. When the GNSS device 34 is described as being located away from the center of rotation 14, it is at least the phase center (or measurement center) of the antenna that is located away from the center of rotation 14. Thus, regardless of the location of the receiver, the position measurements by the GNSS device 34 will change as the platform 11 rotates. This is in contrast to the location of the center of rotation 14, which may not change when the only motion is rotation.

[0032]

[0034] The GNSS device 34 is configured based on a known technology for determining position information using satellite signals, and may be part of any satellite positioning system, such as the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), Galileo, or the BeiDou Navigation Satellite System (BDS).

[0033]

[0035] The excavator also includes sensors for monitoring the position of various machine elements such as the boom 12, stick 16, and bucket 20. For example, the angles of these elements can be determined with respect to gravity using an inclinometer such as an inertial measurement unit (IMU). In the example of FIG. 1, the excavator has an IMU 44 on the boom 12, an IMU 46 on the stick 16, and an IMU 48 on the bucket 20. These IMUs 44, 46, 48 can be used to determine the angles of the bodies 12, 16, 20 with respect to gravity. The IMUs 44, 46, 48, together with the orientation of the excavator platform 11 and the position of the center of rotation 14 in the real world coordinate system, can be used to determine the position of the tines 30 of the bucket 20 in the real world coordinate system. As used herein, the real world coordinate system is a coordinate system based on a reference external to and independent of the excavator.

[0034]

[0036] The excavator of this example also includes a controller 50, which may include one or more processors, memory, and other computing components. The controller 50 is communicatively coupled to the GNSS device 34, the swing sensor 33, and the IMUs 44, 46, 48. The controller 50 may be configured to determine the position of the tines 30 of the bucket 20. This may include determining the angle and rotation of the bodies 44, 46, 48, and determining the coordinates of the center of rotation 14 and the orientation of the excavator platform 11.

[0035]

[0037] In some embodiments, the controller 50 may be configured to obtain an initial orientation of the excavator platform 11 in a real world coordinate system. The initial orientation may be obtained externally or by any known technique such as obtaining position measurements using the GNSS device 34 while rotating the excavator platform 11 to determine the initial orientation, or obtaining position measurements using the GNSS device 34 while translating the excavator by traveling to determine the initial orientation.

[0036]

[0038] The controller 50 may determine the coordinates of the center of rotation 14 of the excavator platform 11 using the initial orientation, the coordinates of the measurement center of the GNSS device 34, and the known spatial relationship between the measurement center of the GNSS device 34 and the center of rotation 14 of the excavator platform 11.

[0037]

[0039] The controller 50 may also use rotation measurements from the swing sensor 33 to track the rotation of the excavator platform 11. Rotation of the excavator platform 11 alone does not change the position of the centre of rotation 14, but traversing the excavator to a new location will change the position of the centre of rotation 14. The rotation measurements from the swing sensor 33 may be used to track the orientation of the excavator platform 11 during and after traversal. This allows the coordinates of the centre of rotation 14 to be determined without obtaining orientation information from any source other than the swing sensor 33 and without performing an orientation initialization procedure after traversal.

[0038]

[0040] 2A-2C are flow charts illustrating an exemplary method for determining the coordinates of an excavator platform's center of rotation and tracking the orientation of the excavator platform, according to some embodiments. The controller 50 of FIG. 1 may be configured to perform all or part of the methods shown in these figures. The methods refer to an excavator platform, but may be implemented in any system including an excavator platform coupled to an undercarriage and suitable sensors.

[0039]

[0041] The method includes obtaining an initial orientation of the excavator platform and associating the initial orientation with a current orientation of the excavator platform (202). The initial orientation can be obtained by any known technique, including obtaining position measurements from a GNSS device while rotating the excavator platform or while translating the excavator by traveling. This initial orientation provides a reference for tracking subsequent rotations using a swing sensor. The initial orientation is typically referenced to a real world coordinate system.

[0040]

[0042] The method also includes obtaining (204) a coordinate of the measurement center from the GNSS device, and determining (206) a coordinate of the rotation center of the excavator platform using an initial orientation of the excavator platform, the coordinate of the measurement center, and a known spatial relationship between the measurement center of the GNSS device and a center of rotation of the excavator platform. If the initial orientation is referenced to a real-world reference system, the coordinate of the rotation center may also be determined in the real-world coordinate system.

[0041]

[0043] In some embodiments, the method also includes tracking a rotation of the excavator platform from the initial orientation to the first orientation using rotation measurements from the swing sensor (208). Once the initial orientation is obtained, the swing sensor can provide a direct rotation measurement of the excavator platform about a vertical axis of rotation that can track the orientation of the excavator platform.

[0042]

[0044] In some embodiments, the method continues with the steps shown in Figure 2B. The excavator may navigate from a first location to a second location (210). The excavator may navigate on the tracks or wheels of an undercarriage. While navigating, the GNSS device is used to track translational movement of the excavator (212). Position measurements from the GNSS device may be obtained at a sampling rate capable of tracking changes in position.

[0043]

[0045] If the excavator platform rotates while navigating, the method may also include tracking (214) the rotation of the excavator platform from a first orientation to a second orientation using rotation measurements from the swing sensor. The swing sensor may provide direct rotation measurements while navigating.

[0044]

[0046] In some embodiments, the method continues with the steps shown in Figure 2C. After traversing the excavator, a second coordinate of the measurement center of the GNSS device is obtained (216), and a second coordinate of the excavator platform's center of rotation is determined (218) using the second orientation, the second coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform.

[0045]

[0047] In some embodiments, the method also includes tracking rotation of the excavator platform from the second orientation to a third orientation after running the excavator using only rotation measurements from the swing sensor, without obtaining orientation information from any source other than the swing sensor, and without performing an orientation initialization procedure after running (220). Because the swing sensor provides direct rotation measurements, the orientation of the excavator can be tracked during and after running and does not need to be reinitialized after the center of rotation moves.

[0046]

[0048] It should be understood that the specific steps illustrated in Figures 2A-2C provide a particular method according to some embodiments. Other sequences of steps may be performed according to alternative embodiments. For example, some embodiments may perform the steps outlined above in a different order. Additionally, some of the individual steps illustrated in Figures 2A-2C may be optional and / or include multiple sub-steps that may be performed in various orders. Additionally, additional steps may be added or removed depending on the particular application.

[0047]

[0049] 3 is a simplified block diagram of an exemplary system for tracking an orientation of an excavator, according to one embodiment. The system includes a GNSS device, a swing sensor, and a controller. The GNSS device and swing sensor may be communicatively coupled to the controller via wired or wireless communication. The controller may be configured to receive inputs from other sensors for determining a position of the implement blade. The controller may also be wired or wirelessly coupled to a display for displaying the position and orientation information.

[0048]

[0050] As previously mentioned, the GNSS device may have a measurement center located away from and arranged in a known spatial relationship to the center of rotation of the platform. The GNSS device may be configured to determine the position of the excavator platform.

[0049]

[0051] The swing sensor may be coupled to the excavator platform or undercarriage at or near a rotation point between the excavator platform and the undercarriage. The swing sensor may be configured to perform rotational measurements of the excavator platform relative to the undercarriage.

[0050]

[0052] The controller may be configured to perform any of the methods described herein. Some embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments to perform the necessary tasks may be stored in a computer readable storage medium, such as a storage medium. A processor may be adapted to perform the necessary tasks. The term "computer readable storage medium" includes, but is not limited to, portable or fixed storage devices, optical storage devices, wireless channels, SIM cards, other smart cards, and various other non-transitory media that can store, store, or transport instructions or data. EXAMPLES

[0051]

[0053] Various examples of the present invention are provided below. As used below, any reference to a series of examples should be understood disjunctively as a reference to each of those examples (e.g., "Examples 1-4" should be understood as "Examples 1, 2, 3 or 4").

[0052] [Example 1]

[0054] 1. A system for tracking an orientation of an excavator, the system comprising: an excavator platform coupled to an excavator chassis along a vertical axis aligned with a center of rotation of the excavator platform, the excavator platform being configured to rotate about the vertical axis, the chassis being configured to support the excavator platform and to effect translational movement of the excavator platform; and a single Global Navigation Satellite System (GNSS) device coupled to the excavator platform, the GNSS device having a measurement center located away from the vertical axis aligned with the center of rotation of the excavator platform, the measurement center being arranged in a known spatial relationship to the center of rotation of the excavator platform, the GNSS device being configured to determine coordinates of the measurement center in a real world coordinate system. a swing sensor coupled to the excavator and configured to measure rotation of the excavator platform about a vertical axis aligned with the center of rotation; and a controller communicatively coupled to the GNSS device and the swing sensor, the controller configured to: obtain an initial orientation of the excavator platform, associate a current orientation and the initial orientation of the excavator platform, obtain coordinates of a measurement center from the GNSS device, determine coordinates of the excavator platform's center of rotation using the initial orientation of the excavator platform, the coordinates of the measurement center and a known spatial relationship between the measurement center of the GNSS device and the excavator platform's center of rotation, and track rotation of the excavator platform from the initial orientation to a first orientation using the rotation measurements from the swing sensor.

[0053] [Example 2]

[0055] In the system of Example 1, the swing sensor is coupled to the excavator platform or undercarriage at a location proximate to the rotation point between the excavator platform and undercarriage.

[0054] [Example 3]

[0056] In the system of Examples 1-2, the controller is configured to obtain an initial orientation of the excavator platform by obtaining multiple coordinates of the measurement center of the GNSS device while rotating the excavator platform, and to determine the initial orientation of the excavator platform using the multiple coordinates.

[0055] [Example 4]

[0057] A system of Examples 1 to 3, wherein the controller is further configured to track the translational movement of the excavator while traveling using coordinate measurements from the GNSS device, and the controller is also configured to track the rotation of the excavator platform while traveling using rotation measurements from the swing sensor.

[0056] [Example 5]

[0058] A system of Examples 1 to 4, wherein the controller is further configured to determine a second coordinate of a center of rotation of the excavator platform after traveling the excavator from the first position to the second position and after rotating the excavator platform from the first orientation to the second orientation, the second coordinate of the center of rotation being determined using coordinate measurements of the GNSS device at the second position and rotation measurements from the swing sensor during rotation from the first orientation to the second orientation.

[0057] [Example 6]

[0059] A system according to any one of Examples 1 to 5, wherein the excavator platform is coupled to an excavator arm including a work implement, and the controller is further configured to determine coordinates of a blade of the work implement in the real world coordinate system using coordinates of a center of rotation of the excavator platform.

[0058] [Example 7]

[0060] The system of Examples 1-6, wherein the swing sensor is configured to measure rotation of the excavator platform by measuring the angular displacement of the excavator platform about a vertical axis aligned with the center of rotation.

[0059] [Example 8]

[0061] A method for tracking an orientation of an excavator using a single Global Navigation Satellite System (GNSS) device and swing sensor, the method including the steps of obtaining an initial orientation of an excavator platform of an excavator and correlating a current orientation of the excavator platform with the initial orientation; obtaining a first coordinate of a measurement center of the GNSS device, the measurement center of the GNSS device being positioned away from a vertical axis aligned with a center of rotation of the excavator platform and arranged in a known spatial relationship to the center of rotation of the excavator platform; determining the first coordinate of the center of rotation of the excavator platform using the initial orientation of the excavator platform, the first coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; and then tracking the orientation of the excavator platform from the initial orientation to the first orientation using rotation measurements from the swing sensor. The method includes tracking the rotation of the platform, wherein the swing sensor is positioned proximate to a rotation point between the excavator platform and the excavator chassis and configured to measure the rotation of the excavator platform around a vertical axis aligned with the center of rotation; then traveling the excavator from a first position to a second position and tracking the translational movement of the excavator using position measurements from the GNSS device while the excavator is traveling; tracking the rotation of the excavator platform from the first orientation to the second orientation using rotation measurements from the swing sensor; after the excavator is traveling, obtaining a second coordinate of the measurement center of the GNSS device; and determining the second coordinate of the excavator platform's center of rotation using the second orientation, the second coordinate of the measurement center of the GNSS device, and a known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform.

[0060] [Example 9]

[0062] A method according to Example 8, wherein the step of obtaining an initial orientation of the excavator platform includes the steps of obtaining a plurality of coordinates of a measurement center of the GNSS device while translating the excavator, and determining an initial orientation of the excavator platform using the plurality of coordinates.

[0061] [Example 10]

[0063] The method of Examples 8-9, further comprising tracking rotation of the excavator platform from the second orientation to a third orientation using only rotation measurements from the swing sensor after traveling the excavator, without obtaining orientation information from any source other than the swing sensor, and without performing an orientation initialization procedure after traveling.

[0062] [Example 11]

[0064] The method of any of Examples 8-10, wherein an initial orientation of the excavator platform is obtained in a real world coordinate system and a second position of the excavator is determined in the real world coordinate system.

[0063] [Example 12]

[0065] The method of Examples 8-11, wherein the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform includes a distance between the measurement center of the GNSS device and the center of rotation along at least one axis in a coordinate system of the excavator platform.

[0064] [Example 13]

[0066] The method of any one of Examples 8 to 12, wherein the excavator platform is coupled to an excavator arm including a work implement, and the method further includes determining coordinates of a blade of the work implement in a real world coordinate system using coordinates of a center of rotation of the excavator platform.

[0065] [Example 14]

[0067] The method of any one of Examples 8-13, wherein the swing sensor is configured to measure rotation of the excavator platform by measuring angular displacement of the excavator platform about a center of rotation.

[0066] [Example 15]

[0068] A method for tracking an orientation of an excavator using a Global Navigation Satellite System (GNSS) device and a swing sensor, the method comprising the steps of: acquiring a first orientation of an excavator platform of the excavator and correlating a current orientation of the excavator platform with the first orientation; acquiring a first coordinate of a measurement center of the GNSS device located away from a vertical axis aligned with a center of rotation of the excavator platform and arranged in a known spatial relationship to the center of rotation of the excavator platform; determining the first coordinate of the measurement center of the excavator platform using the first orientation of the excavator platform, the first coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; the step of: thereafter, navigating the excavator from the first location to a second location; tracking translational movement of the excavator using the GNSS device while the excavator is navigating; tracking rotation of the excavator platform from the first orientation to a second orientation using rotation measurements from the swing sensor, the swing sensor being configured to measure rotation of the excavator platform around a vertical axis aligned with the center of rotation; after the excavator has navigated, obtaining a second coordinate of the measurement center of the GNSS device; and determining the second coordinate of the excavator platform's center of rotation using the second orientation of the excavator platform, the second coordinate of the measurement center of the GNSS device, and a known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform.

[0067] [Example 16]

[0069] The method of Example 15, wherein the swing sensor is coupled to the excavator platform or undercarriage of the excavator at a location proximate to a rotation point between the excavator platform and undercarriage.

[0068] [Example 17]

[0070] A method according to Examples 15 to 16, wherein the step of acquiring a first orientation of the excavator platform includes the steps of acquiring a plurality of coordinates of a measurement center of the GNSS device while rotating the excavator platform, and determining a first orientation of the excavator platform using the plurality of coordinates.

[0069] [Example 18]

[0071] The method of Examples 15-17, further comprising tracking rotation of the excavator platform from the second orientation to a third orientation using only rotation measurements from the swing sensor after traveling the excavator, without obtaining orientation information from any source other than the swing sensor, and without performing an orientation initialization procedure after traveling.

[0070] [Example 19]

[0072] A method according to any one of Examples 15 to 18, wherein the excavator platform is coupled to an excavator arm including a work implement, and the method further includes determining coordinates of a blade of the work implement in a real world coordinate system using coordinates of a center of rotation of the excavator platform.

[0071] [Example 20]

[0073] The method of Examples 15-19, wherein the swing sensor is configured to measure rotation of the excavator platform by measuring angular displacement of the excavator platform about a vertical axis aligned with the center of rotation.

[0072]

[0074] Although the present invention has been described with respect to specific embodiments, it will be apparent to those skilled in the art that the scope of the present invention is not limited to the embodiments described herein. For example, features of one or more embodiments of the present invention may be combined with one or more features of other embodiments without departing from the scope of the present invention. The specification and drawings should therefore be regarded in an illustrative rather than a restrictive sense. The scope of the present invention should therefore be determined not with reference to the above description, but with reference to the appended claims along with their full scope of equivalents.

Claims

1. 1. A system for tracking the orientation of an excavator, comprising: an excavator platform coupled to an undercarriage of the excavator along a vertical axis aligned with a center of rotation of the excavator platform, the excavator platform being configured to rotate about the vertical axis, the undercarriage being configured to support the excavator platform and provide translational movement of the excavator platform; a single Global Navigation Satellite System (GNSS) device coupled to the excavator platform, the GNSS device having a measurement center located away from the vertical axis aligned with the center of rotation of the excavator platform, the measurement center being arranged in a known spatial relationship to the center of rotation of the excavator platform, the GNSS device being configured to determine coordinates of the measurement center in a real world coordinate system; a swing sensor coupled to the excavator and configured to provide a direct measurement at a point of rotation of the excavator platform about the vertical axis aligned with the center of rotation; a controller communicatively coupled to the GNSS device and the swing sensor, obtaining an initial orientation of the excavator platform and relating a current orientation of the excavator platform to the initial orientation; obtaining coordinates of the measurement center from the GNSS device; determining a coordinate of the center of rotation of the excavator platform using the initial orientation of the excavator platform, the coordinate of the measurement center, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; Tracking a rotation of the excavator platform from the initial orientation to a first orientation using rotation measurements from the swing sensor. With a controller configured like this: Equipped with the controller is configured to obtain the initial orientation of the excavator platform by obtaining a plurality of coordinates of the measurement center of the GNSS device while rotating the excavator platform, and to determine the initial orientation of the excavator platform using the plurality of coordinates. system.

2. The system of claim 1 , wherein the swing sensor is coupled to the excavator platform or undercarriage at a location proximate a rotation point between the excavator platform and the undercarriage.

3. 2. The system of claim 1, wherein the controller is further configured to track translational movement of the excavator while traveling using coordinate measurements from the GNSS device, and the controller is also configured to track rotation of the excavator platform while traveling using rotation measurements from the swing sensor.

4. 2. The system of claim 1, wherein the controller is further configured to determine a second coordinate of the center of rotation of the excavator platform after traveling the excavator from a first location to a second location and after rotating the excavator platform from the first orientation to a second orientation, the second coordinate of the center of rotation being determined using coordinate measurements of the GNSS device at the second location and rotation measurements from the swing sensor during rotation from the first orientation to the second orientation.

5. 2. The system of claim 1, wherein the excavator platform is coupled to an excavator arm including a work implement, and the controller is further configured to use the coordinates of the center of rotation of the excavator platform to determine coordinates of a blade of the work implement in the real world coordinate system.

6. The system of claim 1 , wherein the swing sensor is configured to measure the rotation of the excavator platform by measuring angular displacement of the excavator platform about the vertical axis aligned with the center of rotation.

7. 1. A method for tracking an orientation of an excavator using a single Global Navigation Satellite System (GNSS) device and a swing sensor, comprising: obtaining an initial orientation of an excavator platform of the excavator and correlating a current orientation of the excavator platform with the initial orientation; obtaining a first coordinate of a measurement center of the GNSS device, the measurement center of the GNSS device being located away from a vertical axis aligned with a center of rotation of the excavator platform and arranged in a known spatial relationship to the center of rotation of the excavator platform; determining a first coordinate of the center of rotation of the excavator platform using the initial orientation of the excavator platform, the first coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; thereafter, tracking a rotation of the excavator platform from the initial orientation to a first orientation using rotation measurements from the swing sensor, the swing sensor being positioned at a rotation point between the excavator platform and the excavator chassis and configured to measure rotation of the excavator platform about a vertical axis aligned with the center of rotation; Then, the excavator is caused to travel from a first position to a second position, and during the travel of the excavator, tracking translational movement of the excavator using position measurements from the GNSS device; tracking rotation of the excavator platform from the first orientation to a second orientation using rotation measurements from the swing sensor; After the excavator has traveled, obtaining a second coordinate of the measurement centre of the GNSS device; determining a second coordinate of the center of rotation of the excavator platform using the second orientation, the second coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; Including, obtaining the initial orientation of the excavator platform includes obtaining a plurality of coordinates of the measurement center of the GNSS device while translating the excavator; and determining the initial orientation of the excavator platform using the plurality of coordinates. method.

8. 8. The method of claim 7, further comprising: after traversing the excavator, tracking rotation of the excavator platform from the second orientation to a third orientation using only rotation measurements from the swing sensor, without obtaining orientation information from any source other than the swing sensor, and without performing an orientation initialization procedure after the traversal.

9. The method of claim 7 , wherein the initial orientation of the excavator platform is obtained in a real world coordinate system and the second position of the excavator is determined in the real world coordinate system.

10. 8. The method of claim 7, wherein the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform includes a distance between the measurement center of the GNSS device and the center of rotation along at least one axis in a coordinate system of the excavator platform.

11. 8. The method of claim 7, wherein the excavator platform is coupled to an excavator arm including a work implement, and further comprising using the coordinates of the center of rotation of the excavator platform to determine coordinates of a blade of the work implement in a real world coordinate system.

12. The method of claim 7 , wherein the swing sensor is configured to measure the rotation of the excavator platform by measuring angular displacement of the excavator platform about the center of rotation.

13. 1. A method for tracking an orientation of an excavator using a Global Navigation Satellite System (GNSS) device and a swing sensor, comprising: obtaining a first orientation of an excavator platform of the excavator and associating a current orientation of the excavator platform with the first orientation; obtaining a first coordinate of a measurement center of the GNSS device, the measurement center of the GNSS device being located away from a vertical axis aligned with a center of rotation of the excavator platform and arranged in a known spatial relationship to the center of rotation of the excavator platform; determining a first coordinate of the center of rotation of the excavator platform using the first orientation of the excavator platform, the first coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; Then, the excavator is caused to travel from a first position to a second position, and during the travel of the excavator, tracking translational movement of the excavator using the GNSS device; tracking a rotation of the excavator platform from the first orientation to a second orientation using rotation measurements from the swing sensor, the swing sensor configured to provide a direct measurement of rotation of the excavator platform about a vertical axis aligned with the center of rotation; After the excavator has traveled, obtaining a second coordinate of the measurement centre of the GNSS device; determining a second coordinate of the center of rotation of the excavator platform using the second orientation of the excavator platform, the second coordinate of the measurement center of the GNSS device, and the known spatial relationship between the measurement center of the GNSS device and the center of rotation of the excavator platform; Including, obtaining the first orientation of the excavator platform includes obtaining a plurality of coordinates of the measurement center of the GNSS device while rotating the excavator platform; and determining the first orientation of the excavator platform using the plurality of coordinates. method.

14. The method of claim 13 , wherein the swing sensor is coupled to the excavator platform or undercarriage at a location proximate a rotation point between the excavator platform and undercarriage.

15. 14. The method of claim 13, further comprising tracking rotation of the excavator platform from the second orientation to a third orientation using only rotation measurements from the swing sensor after traversing the excavator, without obtaining orientation information from any source other than the swing sensor, and without performing an orientation initialization procedure after traversing.

16. 14. The method of claim 13, wherein the excavator platform is coupled to an excavator arm including a work implement, and further comprising using the coordinates of the center of rotation of the excavator platform to determine coordinates of a blade of the work implement in a real world coordinate system.

17. The method of claim 13 , wherein the swing sensor is configured to measure the rotation of the excavator platform by measuring angular displacement of the excavator platform about the vertical axis aligned with the center of rotation.

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