Patent Description:
Embodiments of the present disclosure are related to vehicles carrying ground maintenance implements and, more particularly, to systems and methods for controlling the vehicle while detecting ground surface and sub-surface objects such as sprinkler heads during ground maintenance operations.

Soil and turf treating machines are well-known for promoting turf health. For example, turf aerators are used to create perforations in a turf surface. Such perforations allow water, air, and nutrients to reach grass roots more effectively. Aeration may be especially beneficial in areas where high soil compaction is common.

While various methods of forming soil perforations are known, one common method involves the use of a set of penetrating coring tines that are driven into the soil surface during operation. Some aerators utilize tubular coring tines that, when withdrawn, extract a "plug" of soil, leaving a perforation in its place. The soil core may be ejected onto the turf, where it eventually breaks down. Other aerators may utilize solid tines.

While highly effective for their intended purpose, coring tines can damage items at or near the turf surface. For instance, irrigation sprinkler heads can sustain substantial damage if contacted by a coring tine. Accordingly, aerator operators typically monitor surroundings areas during aeration to prevent traversing, and damaging, sprinkler heads with the aeration tines. Such active monitoring may decrease aerating efficiency, especially when the operator is inexperienced or unfamiliar with the property. Known ground maintenance vehicles are disclosed in documents <CIT>, <CIT>, <CIT> and <CIT>.

The invention is described according to the subject-matter of the appended claims. Embodiments described herein may provide detection systems and methods that automatically detect ground surface or sub-surface objects prior to potential contact with an implement (e.g., aerator coring tine) associated with a vehicle. In some embodiments, the system may communicate with other systems of the vehicle to allow the vehicle to automatically avoid contact of the implement with the object.

According to a first aspect of the present disclosure, a powered ground maintenance vehicle is provided. The vehicle includes: a chassis supported upon a ground surface by ground contact members; a prime mover attached to the chassis; and a traction drive system powered by the prime mover and adapted to selectively power one or more of the ground contact members to propel the vehicle over the ground surface. The vehicle also includes a maintenance implement carried by the chassis, and a detection system adapted to monitor a detection zone forward of the implement. The detection system is further adapted to detect an object at near the ground surface that passes through the detection zone as the vehicle traverses the ground surface. The detection system is adapted to issue a notification indicative of a location of the object prior to the implement contacting the object.

In a second aspect according to the first aspect, the vehicle further includes an electronic controller adapted to communicate with the detection system, wherein the controller is adapted to issue the notification. In a third aspect according to either one of the first and second aspects, the vehicle further include an implement engagement system adapted to automatically disengage the implement from the ground surface in response to receiving the notification. In a fourth aspect according to any one of the previous aspects, the notification includes one or more of a visual, tactile, or audible notification to an operator controlling the vehicle.

In a fifth aspect, a powered ground maintenance vehicle is provided that includes: a chassis supported upon a ground surface by ground contact members; a prime mover attached to the chassis; a traction drive system powered by the prime mover and adapted to selectively power one or more of the ground contact members to propel the vehicle over the ground surface; and a ground maintenance implement carried by the chassis. The vehicle further includes an implement engagement system connecting the implement to the chassis, wherein the engagement system is adapted to selectively engage the implement with, and disengage the implement from, the ground surface. The vehicle also includes a detection system adapted to monitor a detection zone forward of the implement and detect an object passing through the detection zone as the vehicle traverses the ground surface. The detection system is further adapted to periodically capture object information associated with the object while the object remains in the detection zone. The vehicle also includes an electronic controller supported by the chassis and in communication with both the detection system and the engagement system. The controller is adapted to receive the object information and estimate a time, based upon vehicle ground speed, when the implement will reach the object, and wherein the controller is further adapted to issue a notification to disengage the implement from the ground surface before the implement contacts the object.

In a sixth aspect according to the fifth aspect, the controller is adapted to issue the notification to the implement engagement system, and wherein the implement engagement system is adapted to automatically raise or otherwise disengage the implement from the ground surface before contact of the implement with the object. In a seventh aspect according to either the fifth or sixth aspect, the controller is adapted to command the implement engagement system to automatically lower or otherwise engage the implement with the ground surface after the implement passes the object. In an eighth aspect according to any one of the fifth through seventh aspects, the implement comprises a turf aerator. In a ninth aspect according to any one of the fifth through eighth aspects, the object comprises an irrigation sprinkler head. In a tenth aspect according to any one of the fifth through nineth aspects, the detection system comprises an RFID antenna secured to the vehicle, wherein the RFID antenna is adapted to detect an RFID tag located on or near the object. In an eleventh aspect according to any one of the fifth through nineth aspects, the detection system comprises a microwave radar.

In a twelfth aspect, a method of controlling a vehicle performing a ground maintenance task is provided. The method includes propelling the vehicle in a forward direction over a ground surface, wherein the vehicle includes a chassis and a ground maintenance implement attached to the chassis. The method further includes: engaging the implement with the ground surface; monitoring a detection zone forward of the implement with a detection system comprising a transducer; detecting with the transducer an object at or near the ground surface that passes through the detection zone; and periodically capturing object information associated with the object while the object passes through the detection zone. The method also includes estimating, based upon the object information, a time period before the implement will reach the object, and issuing with the controller a disengage command to an implement engagement system to automatically raise, or otherwise disengage, the implement from the ground surface prior to the implement reaching the object.

In a thirteenth aspect according to the twelfth aspect, The method further includes issuing an engage command with the controller to the implement engagement system to re-engage the implement with the ground surface after the implement has traveled past the object. In a fourteenth aspect according to either the twelfth or thirteenth aspect, the detection system comprises two or more transducers each having a detection area. In a fifteenth aspect according to any one of the twelfth through fourteenth aspects, detecting the object comprises detecting a sprinkler head. In a sixteenth aspect according to any one of the twelfth through fifteenth aspects, detecting the object with the transducer comprises detecting the object using a microwave radar antenna. In a seventeenth aspect according to any one of the twelfth through fifteenth aspects, detecting the object with the transducer comprises detecting a radio frequency identification (RFID) tag associated with the object using an RFID antenna. In an eighteenth aspect according to the seventeenth aspect, capturing the object information comprises capturing and storing object information associated with the RFID tag, wherein the object information comprises, for each RFID tag read, any one or more of: an identity of the RFID antenna; a unique tag identifier; a time; a received signal strength indication (RSSI), a frequency channel of the RFID antenna; a phase shift between signals transmitted from and received by the RFID antenna; and a ground speed of the vehicle. In a nineteenth aspect according to the seventeenth aspect, the method further includes calculating, after the object is no longer detected within the detection zone, one or more tag statistics, the one or more tag statistics comprising any one or more statistics selected from: a presence time period during which the object was detected within the detection zone; a maximum received signal strength indication (RSSI) detected during the presence time period; a minimum RSSI detected during the presence time period; a standard deviation of RSSI detected during the presence time period; a time period between a first detection of the object and a time of the maximum RSSI; a time period between detection of the maximum RSSI and a last detection of the object; a linear distance travelled during which the object was detected; a linear distance travelled between the first detection and the time of the maximum RSSI; and a linear distance travelled between the time of the maximum RSSI and the last detection.

The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of illustrative embodiments will become apparent and appreciated by reference to the following Detailed Description of Exemplary Embodiments and claims in view of the accompanying figures of the drawing.

Exemplary embodiments will be further described with reference to the figures of the drawing, wherein:.

The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structure/components, including but not limited to fasteners, electrical components (wiring, cables, etc.), and the like, may be shown diagrammatically or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or where inclusion of such structure/components is not necessary to an understanding of the various exemplary embodiments described herein. The lack of illustration/description of such structure/components in a particular figure is, however, not to be interpreted as limiting the scope of the various embodiments in any way.

In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other embodiments, which may not be described and/or illustrated herein, are certainly contemplated.

All headings and sub-headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading or sub-heading unless so specified. Moreover, unless otherwise indicated, all numbers expressing quantities, and all terms expressing direction/orientation (e.g., vertical, horizontal, parallel, perpendicular, etc.) in the specification and claims are to be understood as being modified by the term "about. " The term "and/or" (if used) means one or all of the listed elements or a combination of any two or more of the listed elements. " is used as an abbreviation for the Latin phrase id est and means "that is. " is used as an abbreviation for the Latin phrase exempli gratia and means "for example.

Embodiments of the present disclosure are directed to detection systems and methods for detecting objects (e.g., irrigation sprinkler heads, boxes, and/or associated components) at, above, or below a ground surface (e.g., turf surface), and to powered ground maintenance vehicles incorporating the same. Other embodiments are directed to methods of controlling a vehicle performing a ground maintenance task. In some embodiments, the vehicle may include an attachment. The term "attachment" is used herein to refer to most any device or assembly that carries an implement or tool for performing a ground or turf maintenance operation.

As used herein, "object" may refer to any item located at, above, or below the ground surface that is susceptible to damage (or to causing damage) if the object comes into contact with the implement. For example, the object may be an irrigation sprinkler head. However, sprinkler heads are exemplary only as other objects, e.g., irrigation valve boxes, electrical (e.g. landscape) boxes, golf cups, drain tile outlets, utility valve access covers, and the like are also contemplated within the scope of the present disclosure.

As described herein, detection systems and methods in accordance with embodiments of the present disclosure may determine that the vehicle is on a path or course that will intersect the object. When this occurs, the detection system may issue a notification (e.g., disengage notification) indicative of a location of the object prior to the implement contacting, and possibly damaging, the object. In some embodiments, the notification (e.g., disengage notification) may include one or more of a visual, tactile, and/or audible notification to an operator of the vehicle instructing the operator to manually initiate disengagement (e.g., lifting) of the implement before it reaches the detected object.

In other embodiments, the vehicle may include an electronic controller as described herein that is adapted to communicate with the detection system, wherein the controller is adapted to issue the notification (e.g., the disengage notification). The controller may also monitor other vehicle parameters such as ground speed. With knowledge of the ground speed and other parameters such as a distance between a detection zone and the implement, the controller may calculate, during or after object (e.g., sprinkler head) detection, when the implement should be disengaged from the ground surface to avoid contact with the object. At the calculated time, the controller may then issue a notification (e.g., a command) to an implement engagement or "lift" system associated with the vehicle. The implement engagement system may connect the implement to a chassis of the vehicle, and may be adapted to selectively engage the implement with, and disengage the implement from, the ground surface. In some embodiments, the implement engagement system may automatically disengage the implement from the ground surface in response to receiving the disengage notification before the implement contacts the object. One exemplary turf vehicle in which a detection system and controller in accordance with embodiments of the present disclosure may be incorporated is the Outcross turf utility vehicle available from The Toro Company of Bloomington, Minnesota, USA. By incorporating detection systems and methods in accordance with embodiments of the present disclosure, such vehicles may be configured to automatically lift and lower its attachment/ implement to avoid damage to either the object and/or the implement.

In still other embodiments, in addition to or instead of disengaging the implement from the ground surface, the controller could alternatively communicate with an autonomous navigation system associated with the vehicle. Such a configuration may allow the vehicle to effectively and autonomously re-route itself around, and thus avoid contact of the implement with, the detected object.

Regardless of whether the implement is automatically or manually disengaged from the ground surface, the detection system (and/or the vehicle controller) may also determine when the implement has moved beyond the object and issue an engage notification (e.g., to the operator or to the controller) that the implement can again be engaged with the ground surface. Alternatively, the implement may be re-engaged based merely upon the passage of a predetermined period of time for a given ground speed of the vehicle and object size. In still other embodiments, the detection system may be adapted to actively detect when the implement has moved past the object before reengagement with the ground surface.

Thus, embodiments of the present disclosure may allow automatic or semiautomatic detection and implement avoidance of sprinkler heads and other ground surface or sub-surface objects during turf treatment, thus reducing potential head and/or implement damage and the corresponding time and cost associated with corresponding repairs.

With reference to the figures of the drawing, <FIG> illustrates an exemplary vehicle <NUM> (with various structure removed) incorporating a detection system <NUM> in accordance with embodiments of the present disclosure, while <FIG> illustrates portions of the vehicle and detection system diagrammatically. As shown in these views, the vehicle <NUM> may include a chassis <NUM> supported upon a turf or ground surface <NUM> by one or more ground contact members (e.g., wheels, tracks, rollers, etc.) such as rear wheels <NUM> and front wheels <NUM>. One or more of the front and rear wheels may form part of a traction drive system <NUM> adapted to propel the vehicle over the ground surface <NUM>. A prime mover <NUM> may be attached to (or otherwise carried by) the chassis <NUM> near a front end of the vehicle as shown in <FIG>. The prime mover <NUM> may power one or more of the wheels <NUM>, <NUM> of the traction drive system <NUM> to propel the vehicle over the ground surface <NUM>. The prime mover <NUM> (which may be configured as internal combustion engine, electric motor, or any other power source) may also power other vehicle systems and any vehicle attachments.

The chassis <NUM> may further define a riding platform defining an operator compartment <NUM> having a seat <NUM> adapted to support a sitting operator. The operator compartment <NUM> my include various vehicle controls, some of which are further described below. For instance, the operator compartment <NUM> may include accelerator and brake pedals to allow foot control of vehicle speed. A steering wheel <NUM> may also be provided to permit operator control of vehicle direction in a known manner. Other controls and indicators may be provided in the operator compartment <NUM>, e.g., on a dashboard <NUM> or center console <NUM>.

The vehicle <NUM> may further include an attachment system <NUM> connected to the chassis <NUM> to allow a ground maintenance implement to be carried by the chassis. The attachment system <NUM> is adapted to support an attachment <NUM> at a back end of the vehicle <NUM>, although attachment systems capable of supporting attachments near a front or transverse side of the vehicle, as well as beneath the vehicle, are also contemplated. The attachment <NUM> may include an implement <NUM> defined by a plurality of coring tines <NUM> (see. <FIG>) that form a turf aerator. While described as an aerator, attachments providing most any ground maintenance implement are contemplated within the scope of this disclosure. For example, attachments including cutting reels, rotary mower heads, rakes, spreaders, sprayers, dethatchers, etc. may be mounted to the vehicle via the attachment system <NUM> and controlled as described herein.

In some embodiments, the attachment system <NUM> may form a conventional three point linkage <NUM> carried at the rear of the chassis <NUM>. The linkage <NUM> may include a top central link and a pair of lower laterally-spaced links that are pivotally connected to the chassis <NUM>. The rear ends of the top and lower links have pivot connections for allowing various attachments to be mounted thereto either directly or through some type of quick-attach mounting system. One or more hydraulic cylinders (not shown) coupled to the three point linkage <NUM> and powered by a hydraulic system (also not shown) on the vehicle <NUM> allow the attachment/implement to be lowered to an engaged or working position (wherein the implement is engaged with the ground surface <NUM>), and raised to a disengaged or transport position (wherein the implement is disengaged from the ground surface). A drawbar may also be provided at the rear of the chassis <NUM> to permit towing some types of attachments behind the vehicle <NUM>.

While illustrated and described herein as lowering and lifting the attachment to engage and disengage, respectively, the implement from the ground surface, such a configuration is exemplary only as other implements may be engaged and disengaged by other actions, e.g., terminating power to the implement.

A power takeoff shaft (PTO) <NUM> (shown diagrammatically in <FIG> and in broken lines in <FIG>) is also carried on the rear of the chassis <NUM>. The PTO <NUM> provides a mechanical source of power (e.g., via the prime mover <NUM>) that can be used to power or drive the attachment when mounted on the three point linkage <NUM>. The PTO <NUM> can be manually engaged and disengaged by the operator using a PTO switch in the operator compartment (e.g., on the console <NUM> of <FIG>) when operating some types of attachments. In addition to being manually controlled, the PTO <NUM> may be automatically engaged and disengaged by an electronic controller <NUM> (see <FIG>) supported by the chassis <NUM>.

Aspects of the exemplary vehicle <NUM> are further described in <CIT>. Moreover, while described as a general-purpose riding utility vehicle with a detachable implement, embodiments of the present disclosure may be equally applicable to walk-behind or stand-on vehicles, as well as vehicles configured with dedicated implements (e.g., stand-on aerators) without departing from the scope of this disclosure. Moreover, detection systems as described herein may find application to remote and autonomously controlled vehicles as well.

As shown in <FIG>, the detection system <NUM> is adapted to monitor a detection zone <NUM> forward of the implement and detect an object at or near the ground surface <NUM> that passes through the detection zone as the vehicle <NUM> traverses the ground surface. For example, the detection system <NUM> may include one or more sensors or transducers <NUM> adapted to detect objects within a detection area <NUM> of the transducer. The transducers <NUM> may be located on the chassis <NUM> at positions that are forward (e.g., in the direction <NUM>), lateral, and/or beneath the vehicle <NUM> and forward of the attachment <NUM> (implement <NUM>). For example, as shown in <FIG>, the transducers <NUM> may be located near the front end of the vehicle at locations <NUM>. Alternatively, the transducers <NUM> may be located along the transverse sides of (and beneath) the vehicle generally at locations <NUM> (see also <FIG>). Other locations may also be possible. For example, the transducers <NUM> could be attached directly to the implement housing itself.

The transducers <NUM> are capable of detecting objects, e.g., sprinkler heads <NUM>, once the vehicle <NUM> is within a predetermined range of the heads (i.e., once the heads enters the detection zone <NUM>). For example, as shown in <FIG>, the detection system <NUM> may include the one or more transducers <NUM>, which may be selected from: magnetic (magnetometer) transducers; radio frequency identification (RFID) or near field communication (NFC) transducers; vision-based transducers; microwave radar transducers; and real-time kinematic assisted GPS (RTK GPS) transducers. As used herein, "transducer" and "sensor" are used interchangeably to refer to any device, module, antenna, transmitter, receiver, transceiver, and associated components that permits detection and/or measurement of one or more parameters associated with a detected object (e.g., sprinkler head) and generation of electrical signals representative thereof.

In general, RFID technology uses radio waves to induce a current in a powerless "tag" <NUM> located on or near the object (e.g., attached to the sprinkler head <NUM>) and optionally reads back information stored in that tag. A magnetometer, on the other hand, measures magnetic waves. Thus, by placing a known magnetic tag <NUM> on each sprinkler head <NUM>, the head positions may be detected. Microwave radar, on the other hand, may determine a magnitude and frequency of an echo or return signal from the sprinkler head <NUM> and apply the Doppler shift principle to estimate a relative distance. While no tagging of the sprinkler head is required with microwave radar, some type of object (head) characterization may initially be required. The transducers <NUM> could also include digital imaging sensors adapted to utilize pattern recognition algorithms to detect the sprinkler head <NUM> location in sequential images. Finally, RTK GPS may utilize a map of the surrounding area wherein the locations of the objects, as well as the real-time position of the vehicle, are known.

Regardless of the transducer used, embodiments of the present disclosure may provide a detection system that can be placed upon the vehicle <NUM> (or upon the attachment or implement) to detect objects and initiate actions that minimize potential implement/object contact and resulting damage (e.g., by notifying the operator to initiate lifting or by automatically lifting the implement). After moving beyond the object, the implement may be commanded to resume normal operation by again lowering or otherwise engaging with the ground surface <NUM>.

<FIG> is a partial diagrammatic representation of the vehicle <NUM> incorporating the exemplary detection system <NUM>. As shown in this view, the vehicle may include the electronic controller <NUM> adapted to monitor and control various vehicle functions. The exemplary controller <NUM> may include a processor <NUM> and memory <NUM>, where the processor <NUM> receives various inputs and executes one or more computer programs or applications stored in the memory <NUM>. The memory <NUM> may include computer-readable instructions or applications that, when executed, e.g., by the processor <NUM>, cause the controller <NUM> to perform various calculations and/or issue various commands. That is to say, the processor <NUM> and memory <NUM> may together define a computing apparatus operable to process input data and generate the desired output to one or more components/devices.

In addition to receiving inputs from the detection system <NUM>, the controller may receive various other inputs regarding vehicle operation. For example, the controller may receive input or signal <NUM> from a ground speed sensor <NUM>, such signal representative of a vehicle ground speed. Other inputs <NUM> may include signals or data regarding engine speed, engine temperature, operator control inputs such as pedal or steering wheel position, PTO switch position, paddle control <NUM> (see <FIG>) position etc. Moreover, the controller <NUM> may transmit various commands and/or data to other vehicle systems and components. For instance, the controller <NUM> may transmit various commands to an implement engagement system <NUM> associated with the attachment system <NUM>. Such commands may include a "lift" command to disengage the implement from the ground surface, and a "lower" command to return the implement to engagement with the ground surface. Of course, the controller <NUM> may provide other outputs <NUM> including, for instance, to vehicle control systems such as the traction drive system <NUM>, to the PTO <NUM>, to operator indicators, etc. In fact, in some embodiments, the controller may form part of a "drive-by-wire" system wherein various vehicle parameters and some or all operator inputs are provided to the controller and the controller generates appropriate outputs based thereon.

Accordingly, the controller <NUM> may be in communication with both the detection system <NUM> and the implement engagement system <NUM> and is adapted to receive object information and estimate a time, based upon vehicle ground speed, when the implement will reach the object. The controller is further adapted to issue the notification to disengage the implement from the ground surface before the implement contacts the object.

As further shown in <FIG>, the detection system may include the transducers <NUM> as well as one or more associated electronic processing modules <NUM> adapted to store and process various information, including information from the transducers, and transmit resulting electrical signals to the vehicle controller <NUM>. For example, when the detection system utilizes RFID technology, the transducers <NUM> may be RFID antennas that provide data to one or more processing modules <NUM>. The processing module(s) <NUM> may then process the antenna data and generate electrical signals that are then provided to the controller <NUM>. In this context, the vehicle controller <NUM> may form part of the detection system <NUM> or, alternatively, the detection system may include a controller separate from the controller <NUM>.

The functionality of the controller <NUM> may be implemented in any manner known to one skilled in the art. For instance, the memory <NUM> may include any volatile, non-volatile, magnetic, optical, and/or electrical media, such as a random-access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, and/or any other digital media. While shown as both being incorporated into the controller <NUM>, the memory <NUM> and the processor <NUM> could be contained in separate modules.

The processor <NUM> may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or equivalent discrete or integrated logic circuitry. In some embodiments, the processor <NUM> may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and/or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller/ processor herein may be embodied as software, firmware, hardware, or any combination thereof. In at least one embodiment, various subsystems of the vehicle <NUM> as described above could be connected in most any manner, e.g., directly to one another, wirelessly, via a bus architecture (e.g., controller area network (CAN) bus), or any other connection configuration that permits data and/or power to pass between the various components and systems of the vehicle.

<FIG> is a bottom plan view of the vehicle <NUM>. As shown in this view and stated above, the detection system <NUM> may include an array of transducers <NUM> located forward of the implement, e.g., at a front end of the vehicle (location "A"), or longitudinally between the front a rear wheels <NUM>, <NUM> (location "B").

<FIG> is a top plan view of the vehicle <NUM> of <FIG> during operation of the implement over the ground surface <NUM>, the latter containing sprinkler heads <NUM> at various locations. As shown in this view, the detection system <NUM> (e.g., transducers <NUM>) may continuously scan for sprinkler heads <NUM> that enter into the detection zone <NUM>. To minimize contact of the implement <NUM> with the heads <NUM>, the detection zone <NUM> - in addition to being located forwardly of the implement - also preferably extends laterally outboard past a width of the implement.

By tracking each head <NUM> as it moves through the detection zone <NUM>, the detection system <NUM> may determine if the head <NUM> is within the path of the moving implement. If the head <NUM> is within the path, the system <NUM> may (e.g., via the controller <NUM>) issue a disengage notification, e.g., disengage command <NUM>, as shown in <FIG>. As stated above, the disengage notification may be provided to the implement engagement system <NUM> to command the system <NUM> to automatically raise or otherwise disengage the implement from the ground surface <NUM> before contact of the implement with the object/head. After the implement has moved past the detected head <NUM> (which passage may be estimated based upon speed of the vehicle and passage of a corresponding period of time), the controller may command the implement engagement system <NUM> to automatically lower or otherwise engage the implement with the ground surface (e.g., return the implement to its ground-engaging, operating position).

While systems and methods described herein may have application to various ground maintenance attachments/implements and corresponding detection of different ground surface or sub-surface objects, the following exemplary embodiments are described in the context of a turf core aerator <NUM> and a detection system <NUM> adapted to detect, and avoid damage to, sprinkler heads <NUM> associated with an underground irrigation system. Thus, the terms "aerator," "implement," and "attachment" may be used interchangeably herein, as may the terms "object," "head," and "sprinkler head.

In some embodiments, ultra-high frequency (UHF) RFID (e.g., in the <NUM>-<NUM> megahertz (MHz) range) may be used to detect a tag <NUM> (see. <FIG>) attached or otherwise associated with each of the sprinkler heads <NUM>. The tags may include a generic identifier, or each tag/head combination may be uniquely tied to its particular geographic location.

Each RFID transducer or antenna <NUM> may be located at a forward location on the vehicle chassis <NUM> as shown in <FIG> and be directed downwardly (perpendicular to the ground surface <NUM>). In the embodiment illustrated in <FIG>, a three transducer array may locate an antenna near the vehicle centerline <NUM>, and antennas on each transverse side thereof. As a result, each antenna <NUM> may create an independent detection area <NUM> at the ground surface that is generally circular or oblong in shape as shown in <FIG>, wherein an effective diameter of the detection area <NUM> is dependent on the elevation of the antenna <NUM> above the ground surface <NUM>. The combined areas <NUM> may form the detection zone <NUM> as shown in <FIG>. As illustrated, the three-antenna RFID array detection zone <NUM> may have detection areas <NUM> that overlap one another to improve coverage and detection capability as further described below. As indicated in <FIG>, the antennas <NUM> may each provide data to the RFID processing module <NUM> which, in turn, may communicate with the controller <NUM>. It is noted that, while three antennas <NUM> are illustrated, embodiments using one, two, or four or more antennas are also contemplated.

As used herein, the term "forward" may be used to refer to the location of the detection zone relative to the operational direction of the implement. Accordingly, the transducers and detection zone may be forward of the implement when the vehicle moves in a forward direction (direction <NUM> in <FIG>) during implement operation. However, the transducers and detection zone could, in other embodiments, be actually "behind" the implement where the implement is intended to operate when the vehicle moves in a reverse direction without departing from the scope of this disclosure.

During aeration, the vehicle <NUM> may be propelled forwardly (e.g., in a forward direction <NUM> at a rate of <NUM> meters/second (m/s) to <NUM>/s (e.g., <NUM> miles/hour (mph) to <NUM> mph)). During this forward motion of the vehicle, each antenna <NUM> of the detection system <NUM> may continuously scan for tags <NUM>. When one of the antennas detects a tag <NUM>, the system may compare the received signal strength indication (RSSI) to a "fingerprint" database of values stored within a memory of the processing module.

By observing changes in tag information over time, and by monitoring which antennas <NUM> detect the tag <NUM>, the detection system <NUM> may estimate a location of the tag <NUM>, and thus the sprinkler head <NUM> relative to the vehicle/implement and determine whether the tag/head is in the path of the travelling aerator <NUM>. As stated above, the detection system <NUM> may then communicate with the vehicle controller (see, e.g., controller <NUM> in <FIG>), which, as stated above, may also receive the signal representative of vehicle ground speed. The detection system, via the controller <NUM>, may then, based upon the vehicle ground speed and the tag information detected by the antenna(s), calculate when the head <NUM> may otherwise make contact with the aerator <NUM> and issue a disengage notification to command the implement engagement system <NUM> to automatically lift the aerator at the appropriate time to avoid contact with the sprinkler head <NUM>.

After the implement has passed the sprinkler head, the controller <NUM> may issue an engage notification to command the implement engagement system <NUM> to lower the aerator <NUM>. In some embodiments, the command may be issued after a predetermined (or calculated) period of time has elapsed, e.g., based upon the speed of the vehicle. In other embodiments, the same or different transducers <NUM> may actively detect when the aerator <NUM> has moved past the sprinkler head and inform the controller <NUM>, after which the aerator may again be lowered.

<FIG> illustrates an exemplary detection area <NUM> for one of the antennas <NUM>. As described below, tag information detected by the antenna <NUM> may allow the detection system <NUM> to estimate where the sprinkler head <NUM>/tag <NUM> is at any given time within the respective detection area <NUM>. For example, based upon the identifier information, the detection system <NUM> may determine that a tag is entering the detection area <NUM>, e.g., entering an outer range or "ring" <NUM> of the detection area. On the next read, the tag may be estimated (e.g., based upon RSSI) to lie within ring <NUM> inboard of ring <NUM>. If subsequent readings remain in ring <NUM> and ultimately again in ring <NUM>, the detection system <NUM> can determine that relative path or movement of the tag <NUM>/head <NUM> is along an outer periphery of the detection area <NUM> as indicated by either line <NUM> or line <NUM>. That is, by analyzing a sequential series of tag readings, the particular location of the head path relative to the antenna <NUM> may be generally identified in this instance as being either along line <NUM> or line <NUM>. Similarly, if the readings show passage of the tag from ring <NUM> to ring <NUM> and then through rings <NUM> and <NUM>, the timing of the readings and the identifier information may be used to indicate that relative movement of the tag is, for example, generally along either line <NUM> or <NUM>. Note that while the detection area <NUM> is illustrated herein with four distinct ranges or rings, such an embodiment is for illustration purposes only, e.g., any number of "rings" are contemplated. Of course, other tag information (e.g., signal phase shift, etc.) may also be used to estimate tag/head location and movement through the detection area <NUM>.

As one can appreciate, estimating a position of the tag/head relative to a single antenna <NUM> may be insufficient to determine if the head is within the path of the aerator <NUM>. For instance, as shown in <FIG>, based upon sequential readings, the right antenna <NUM>-<NUM> may be unable to determine if the path of the head <NUM> is laterally outboard of the antenna (represented by line <NUM> in <FIG>), or laterally inboard (line <NUM>) as the tag identifier information may be similar. If passing along the outboard side (line <NUM>), raising of the aerator <NUM> may be unnecessary as the head <NUM> will pass laterally beyond the aerator. However, if the head is passing along the inboard side of the detection area <NUM> (along line <NUM>) of antenna <NUM>-<NUM>, the head may lie within the path of the aerator <NUM>.

To determine which head/tag path is correct, detection from the other antennas (represented in <FIG> as center antenna <NUM>-<NUM> and left antenna <NUM>-<NUM>) may be used. For instance, if the head <NUM> moves along the path <NUM>, antenna <NUM>-<NUM> will also read the head/tag passing through its detection area <NUM>. In fact, with the overlap of the two detection areas, any head <NUM> may be detected within two detection areas <NUM> simultaneously. However, if the path of the head/tag is instead along line <NUM>, antenna <NUM>-<NUM> (as well as antenna <NUM>-<NUM>) will not register the tag. In this case, the detection system <NUM> can accurately determine that path <NUM> is the actual head path.

Once the relative tag path is identified by sequential tag reads, the processing module <NUM> may inform the vehicle controller <NUM> (see <FIG>) as to when the tag is no longer detected, indicating that the tag/head has now passed completely through the relevant detection areas <NUM>. Based upon this event, the controller <NUM> may determine, based upon vehicle speed and distance <NUM> (see <FIG>) from the detection zone <NUM> to the aerator <NUM>, when to issue a disengage notification commanding the implement engagement system <NUM> to disengage the aerator from the ground surface. Moreover, the controller <NUM> may, after the aerator <NUM> has moved past the head, issue the engage notification automatically commanding the implement engagement system to re-engage the aerator with the ground surface.

<FIG> illustrates an exemplary process <NUM> for operating the vehicle <NUM> using the method described with reference to <FIG>. The process is entered at <NUM>. Once the implement is determined to be operating and engaged with the ground surface as determined at <NUM>, the vehicle may be propelled in a forward direction (see, e.g., direction <NUM> in <FIG>) over the ground surface <NUM>. The transducers (antennas <NUM>) may monitor the detection zone <NUM> forward of the implement by scanning for tags <NUM> at <NUM>. If a tag (e.g., "tag ID x") is detected at <NUM> (e.g., the tag passes through the detection zone), the detection system <NUM> may estimate or "place" the tag within one of the ranges (see, e.g., rings <NUM>-<NUM> in <FIG>) of the tag's detection area <NUM> of the detection zone <NUM> at <NUM>. The estimated location of the tag <NUM> may be updated at <NUM>, e.g., based upon changes in tag identifier information, detection by other antennas <NUM>, etc., after which control returns to <NUM>.

If no tag is detected at <NUM>, the detection system <NUM> may determine whether the tag ID x was previously detected at <NUM>. If tag ID x was not previously detected, control returns to <NUM>. If, on the other hand, tag ID x was previously detected at <NUM> (indicating that the tag has moved entirely through the relevant detection area <NUM> of the specific antenna <NUM>), the detection system <NUM> and/or the vehicle controller <NUM> may calculate, based upon a ground speed of the vehicle <NUM> and the distance <NUM> from the detection zone to the aerator, the time delay (Tdelay) to expire before the aerator should be lifted to avoid damage to the sprinkler head at <NUM>. Once Tdelay has expired at <NUM>, the controller <NUM> may issue a disengage notification (e.g., a command to the implement engagement system (e.g., system <NUM> of <FIG>) to disengage or lift the implement/aerator from the ground surface) at <NUM>. The process <NUM> may then optionally determine whether the implement has moved past the object/sprinkler head at <NUM>. If yes, then the detection system (via the controller <NUM>) may issue an engage notification (e.g., a command to the implement engagement system <NUM> to engage or lower the implement/aerator to the ground surface) at <NUM>. Assuming the aerator is still operating as determined at <NUM>, control is returned to <NUM>. If the aerator is deactivated (e.g. no longer operating) at <NUM>, the process ends at <NUM>.

As indicated above, the process <NUM> of <FIG> may rely on associating tag location (relative to a particular antenna) using the fingerprint database. While not wishing to be bound to any particular embodiment, the fingerprint database may be empirically populated (e.g., prior to vehicle operation) by logging tag data at various locations around a specific antenna and recording the tag information (e.g., RSSI, frequency, phase) at those corresponding locations. Machine learning algorithms may then be used to generate a decision tree that calculates the location (e.g., what range <NUM>-<NUM> in <FIG>) of the tag relative to that antenna.

While effective, accuracy of such methods may depend somewhat on specific tag orientation relative to the antenna(s) at time of read. Accordingly, variability in implement disengagement (lift) timing calculations may occur. To address such issues, an alternative process <NUM> for operating the vehicle <NUM> is illustrated in <FIG>. The process <NUM> may use the same vehicle <NUM> and RFID antenna array as already described herein. However, tag movement paths may be better estimated by evaluating additional tag information (e.g., in place of the fingerprint database) as indicated below.

The process <NUM> is entered at <NUM>. Upon determining that the implement is operating and engaged with the ground surface <NUM> at <NUM> (e.g., engagement of the powered aerator with the ground surface), the vehicle may be propelled in the forward direction over the ground surface and the detection system <NUM> may begin monitoring the detection zone <NUM> for objects (e.g., scan for sprinkler heads <NUM>/RFID tags <NUM>) at <NUM> using the transducers (RFID antennas <NUM>). If a particular object/tag (tag ID x attached to a sprinkler head) is detected or "read" via one of the antennas at <NUM> (e.g., if an object is detected passing through the detection zone), the detection system may then determine if this is the first detection of tag ID x at <NUM>. If so, then the detection system may add tag ID x to a tag database and further log present tag information for tag ID x into the tag database at <NUM>, wherein control then returns to <NUM>. If, on the other hand, the system determines at <NUM> that it is not the first detection of tag ID x (i.e., tag ID x is already in the tag database), present tag information for tag ID x may be logged into tag database at <NUM>, after which control again returns to <NUM>.

As used herein, the phrase "first detection" of a tag (tag ID x) refers to the first detected tag reading upon entrance of tag ID x into the detection zone. Once tag ID x has exited the detection zone, any subsequent reading of tag ID x would be registered as another first detection. Further as used herein, the term "tag database" refers to a data set that includes tag IDs and their associated tag (object) information for tags that are currently detected (including, as described below, those that are not currently detected, but were detected within a previous period of time indicating passage of the tag through the detection zone is complete).

While not an exhaustive list, "tag information" (also referred to herein as "object information") may include for each tag reading, any one or more of: an identity of the specific detecting antenna; a unique tag identifier; a time (of the tag reading); a received signal strength indication (RSSI); a frequency channel of the detector/antenna; a phase shift between signals transmitted from and received by the detector/antenna; and a ground speed of the vehicle (as provided by the sensor <NUM> of <FIG> to the controller <NUM>).

If tag ID x is not detected at <NUM>, the process <NUM> may next determine whether tag ID x was previously detected at <NUM>. If not, control is returned to <NUM>. If, however, it is determined that tag ID x was previously detected at <NUM>, the process may determine if the tag was detected in the past y seconds at <NUM>. If tag ID x was detected in the last y seconds, control may return to <NUM>. If, on the other hand, the determination at <NUM> is that tag ID x has not been detected in the past y seconds, the detection system may calculate various object or tag statistics for tag ID x over the read duration at <NUM>. As one can appreciate, the detection system may thus be adapted to periodically capture (e.g., at each tag read) object or tag information associated with the object (sprinkler head) while the object remains in the detection zone.

The value of y used at <NUM> may be selected to ensure that a missing detection of tag ID x is not due to external factors such as radio interference or lack of detection at a certain antenna frequency. Exemplary values of y may range from <NUM> seconds (sec) to <NUM> sec. For instance, <NUM> seconds has been found sufficient to allow for a potential missed detection without erroneously concluding that the tag has passed through the detection zone.

While not exhaustive, the tag statistics calculated at <NUM> may include any one or more of: a presence time period during which the tag/object was detected within the detection zone (the time period that the tag/object was within the detection zone); a maximum RSSI detected during the presence time period; a minimum RSSI detected during the presence time period; a standard deviation of RSSI detected during the presence time period; a time period between a first detection of the object and a time of the maximum RSSI; a time period between detection of the maximum RSSI and a last detection of the object; a linear distance travelled during which the object was detected; a linear distance travelled between the first detection and the time of the maximum RSSI; and a linear distance travelled between the time of the maximum RSSI and the last detection.

With knowledge of current vehicle speed and certain vehicle parameters (the latter including, for instance, the distance <NUM> (see <FIG>) and the time required to disengage (e.g., lift) the implement from the ground surface), the vehicle controller <NUM> may estimate a time period before the implement will reach the object. Based upon this estimate, the controller may calculate a delay time "Tdelay" to expire before implement disengagement from the ground surface <NUM> is needed to avoid object contact at <NUM>. Once Tdelay has expired at <NUM>, the detection system (e.g., controller <NUM>) may issue a disengage notification to disengage the implement from the ground surface at <NUM>.

While Tdelay may vary (e.g., for different implements, different vehicle configurations, different vehicle speeds, etc.), it is in some embodiments selected to ensure that the implement may continue to operate until it is close to the object without resulting in contact of the implement with the object.

In some embodiments, the disengage notification may be a command or signal <NUM> transmitted to the implement engagement system <NUM> (see <FIG>) that causes the implement to automatically raise or otherwise disengage from the ground surface <NUM> at the appropriate time (e.g., prior to the implement reaching the object). In other embodiments, the disengage notification <NUM> could be a visual, tactile, and/or audible alert provided to the operator control console (e.g., to a display <NUM> as shown in <FIG> and <FIG>). Upon receipt of such notification, the operator could manually disengage the implement from the ground surface using the paddle control <NUM> (<FIG>) as further described below.

In some embodiments, the process <NUM> may include additional steps <NUM> and <NUM> as shown in <FIG>. More specifically, in addition to issuing the disengage command or notification to disengage the implement from the ground surface, the detection system (e.g.. , controller <NUM>) may also determine when the implement is clear of or has moved past the object at <NUM> and issue an engage command or notification to engage or re-engage the implement with the ground surface at <NUM>. After <NUM>, the process may return to <NUM> or end at <NUM> depending on whether the implement is determined to still be operating at <NUM>.

As with the implement disengage notification, the implement engage notification may be automated such that the implement automatically re-engages the ground surface after the implement has cleared the object. For example, the engage notification may be a signal transmitted to the lift system <NUM> that automatically lowers the implement at the appropriate time. In some embodiments, the engage notification may be sent at a specific time following the disengage notification, such time being fixed or variable based upon vehicle speed and/or other parameters. In yet other embodiments, transducers (e.g., another set of RFID antennas) could be provided to monitor the area behind the implement and issue the engage notification once the object/tag is detected as being past (behind) the implement. In still yet other embodiments, the engage notification could be provided to the operator, at which point the operator could manually command the implement to re-engage with the ground surface.

Like the RFID methods described above, other embodiments may use radar to detect objects such as sprinkler heads, and even buried objects, and inform the vehicle operator of (or automatically lift the implement/aerator to avoid contact with) the head/object when the latter is determined to be within the oncoming path of the aerator. Radar detection may include the added benefit of head avoidance without the need to first affix tags or other targets to the sprinkler heads.

For example, in some embodiments, the detection system <NUM> may include a microwave radar having a transmitting/receiving antenna <NUM> as shown in <FIG> that is adapted to transmit energy in the microwave frequency band range of <NUM> to <NUM> Gigahertz (GHz) (e.g., X-band frequency of <NUM> to <NUM>) corresponding to a range of wavelengths of <NUM> meter (m) to <NUM> millimeter (mm), respectively. With such a transmission source, the detection system <NUM> may rely upon the principle of Doppler shift to estimate location of objects (e.g., sprinkler heads) that are within the approaching path of the aerator <NUM>. As is known in the art, "Doppler shift" refers to a change in frequency or wavelength of a wave in relation to a detector/observer that is moving relative to the wave source.

Accordingly, detection systems <NUM> utilizing microwave radar may utilize antennas <NUM> that emit energy at the frequency and range described above and measure a reflected magnitude and frequency of the return signal (e.g., the Doppler shift). The magnitude of the Doppler shift is proportional to the reflection of transmitted energy, and the frequency of the Doppler shift is proportional to velocity of the object relative to the vehicle <NUM>/antenna <NUM>. This relationship may be mathematically expressed as shown in Equation <NUM> below. <MAT> Wherein:.

In operation, the Doppler radar antenna <NUM> may be mounted on top of the vehicle <NUM> (e.g., at a location <NUM> in <FIG>). The antenna may transmit microwave energy forwardly in, for example, the <NUM> X-band. Materials of different permittivity (dielectric constant) will reflect energy magnitude and frequency data back to the Doppler radar antenna. Accordingly, sprinkler heads will provide a different radar reflection than the surrounding turf.

As indicated in <FIG>, data from the detected object (sprinkler head <NUM>) is received by the radar antenna <NUM>. These data may be fed into a machine learning (ML) software environment <NUM>, which may run within a processing module <NUM> (or in the controller <NUM>), to do inference of neural network (NN) artificial intelligence (AI) models on embedded systems for finding patterns and rules in the data. These inferred data may be stored in memory <NUM> for post-detail analysis and compared to a local library <NUM> of object identification information for machine control (MC). The processing module <NUM> may, like the RFID processing module described above, be in communication with the implement engagement system <NUM> by way of the vehicle controller <NUM>. Accordingly, like the RFID detection system described above, the microwave radar detection system may identify sprinkler heads <NUM> and issue notifications or commands (e.g., using the vehicle controller <NUM>) to the implement engagement system <NUM> to reduce or eliminate unintended contact of the aerator <NUM> with the heads <NUM>.

While embodiments above describe automating implement lift, detection systems <NUM> are also contemplated for use with vehicles that do not include a vehicle controller (e.g., the controller <NUM>) that can automate such tasks. In such instances, the detection system <NUM> may simply notify the operator, via audible, tactile, or visual cues to raise the implement at the appropriate time. For example, <FIG> is a partial perspective view of the exemplary operator compartment <NUM> of the vehicle <NUM>. As shown in this view, the operator compartment <NUM> may include various controls including the paddle control <NUM> as well as one or more displays <NUM>. As it lacks the controller <NUM>, the disengage notification at <NUM> in <FIG> may be a visual notification to the display <NUM>, wherein such notification provides red, green, and yellow lights. Upon detection of a sprinkler head having passed through the detection zone as already described herein, the notification may change from green to yellow to indicate an approaching head and to initiate implement lift. As more time elapses, the light may change to red, indicating that the head is beneath the aerator and that the aerator should not be lowered. Once sufficient time has passed, the light may change again to green, indicating that the aerator may again be lowered and operated.

In some embodiments, the operator may respond to the disengage notification (e.g., yellow light) by pulling on the paddle control <NUM>. Such manipulation of the paddle control may cause the implement disengagement system <NUM> to lift the implement. In a similar manner, the display <NUM> may also display the engage notification identified at <NUM> in <FIG> (e.g., using the green light). Upon observance of the engage notification, the operator may push on the paddle control <NUM>, causing the implement engagement system <NUM> to once again lower or otherwise engage the implement with the ground surface.

In the case of vehicles lacking a vehicle controller, the notifications may occur without knowledge of vehicle ground speed. Accordingly, the notifications may be configured to safely indicate lift assuming a relatively high ground speed and indicate implement lowering assuming a slow ground speed. While such operation may avoid aerator coverage of desired areas around the heads, it may also lessen the opportunity for sprinkler head contact/damage.

In still other embodiments, the vehicle may lack the detection systems described herein, but include the vehicle controller <NUM>. In such embodiments, reliance on operator observance and manual operator initiation of disengage/engage commands may be necessary. For example, <FIG> illustrates a partial side view of a vehicle <NUM> similar in most respects to the vehicle <NUM> described above but lacking the associated detection system. Prior to operation of the implement (not shown), the operator may calibrate his or her line of sight <NUM> through a site <NUM> attached to the vehicle (e.g., attached to an edge of the vehicle hood). Such calibration may occur by, for example, adjusting the site or a height of the operator's seat <NUM>. During operation, alignment of the object <NUM> with the site <NUM> (along the operator's line of sight <NUM>) may serve as a disengage notification to the operator to disengage the implement from the ground surface. The operator may then trigger a control (e.g., pull on the paddle control <NUM>) indicating the presence of the object <NUM>.

Claim 1:
A powered ground maintenance vehicle (<NUM>) comprising:
a chassis (<NUM>) supported upon a ground surface (<NUM>) by ground contact members (<NUM>, <NUM>);
a prime mover (<NUM>) attached to the chassis;
a traction drive system (<NUM>) powered by the prime mover (<NUM>) and adapted to selectively power one or more of the ground contact members (<NUM>, <NUM>) to propel the vehicle (<NUM>) over the ground surface (<NUM>);
a ground maintenance implement (<NUM>) carried by the chassis (<NUM>);
an implement engagement system (<NUM>) connecting the implement (<NUM>) to the chassis (<NUM>), the engagement system (<NUM>) adapted to selectively engage the implement (<NUM>) with, and disengage the implement from, the ground surface (<NUM>);
a detection system (<NUM>) comprising a Radio Frequency Identification (RFID) antenna (<NUM>) adapted to monitor a detection zone (<NUM>) forward of the implement (<NUM>) and detect an RFID tag (<NUM>) located on or near an object (<NUM>) passing through the detection zone (<NUM>) as the vehicle (<NUM>) traverses the ground surface (<NUM>), wherein the detection system (<NUM>) is further adapted to periodically capture object information associated with the object (<NUM>) while the object (<NUM>) remains in the detection zone (<NUM>); and
an electronic controller (<NUM>) adapted to communicate with the detection system (<NUM>), wherein the controller (<NUM>) is adapted to receive the object information
characterized in that:
the controller (<NUM>) is further adapted to estimate a time, based upon vehicle (<NUM>) ground speed, when the implement (<NUM>) will reach the object (<NUM>), and wherein the controller (<NUM>) is further adapted to issue a notification to disengage the implement (<NUM>) from the ground surface (<NUM>) before the implement (<NUM>) contacts the object (<NUM>).