SYSTEM WITH COMMAND LOOPING SATURATION AND AUTOPILOT HEADING
20240036589 ยท 2024-02-01
Inventors
Cpc classification
B63H2025/384
PERFORMING OPERATIONS; TRANSPORTING
B63H25/382
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A stability control system configured for total vessel pitch axis control by fast symmetric deployment of devices, coupled with engine trim adjustments and total roll and heading control by differentially deploying devices to counter rolling motions while simultaneously adjusting engine steering position to counter the steering moment associated with device delta position. The system includes a software control strategy comprising (1) a command looping saturation strategy to reduce drag and/or maximize roll performance and provide real-time ride stability to deliver a consistent device delta position even when one or more devices is at their minimum possible bias; and (2) an autopilot heading strategy comprising a feedback loop with means of actuation provided by the engine steering/rudder position and at least one pair of devices capable of producing a yaw moment.
Claims
1. A dynamic active control system for a marine vessel comprising: a software module, a plurality of sensors and a plurality of water engagement devices, wherein each of the water engagement devices includes an actuator and a blade connected to the actuator and is configured to mount adjacent a transom of the marine vessel; wherein the software module is communicatively and operatively connected to the plurality of sensors and to each water engagement device to iteratively command activation of the actuator and deployment of the blade in response thereto based on data received from the plurality of sensors and a desired setting; and wherein the software module includes a control strategy that further iteratively commands activation of the actuators to generate a water engagement device delta position when one of the water engagement devices reaches a pre-determined threshold of one of a depth of deployment of the one of the water engagement devices and a speed of deployment of the one of the water engagement devices as a function of the data received from the plurality of sensors related to a speed of the marine vessel.
2. The system of claim 1, wherein the control strategy is configured to further iteratively commands activation of the actuators to generate a maximum trim angle without changing the water engagement device delta position.
3. The system of claim 1, wherein pre-determined threshold of one of a depth of deployment of the one of the water engagement devices and a speed of deployment of the one of the water engagement devices is defined as a bias of the one of the water engagement devices.
4. The system of claim 1, further comprising: an adjustable steering position control embedded within the engine control module wherein the software module is further configured to (a) provide a first signal output to the plurality of water engagement device actuators to command a water engagement device delta position in order to combat dynamic motions of the marine vessel; and (b) measure a relationship between the water engagement device delta position and, in response thereto, provides a second signal output to the plurality of water engagement device actuators; wherein the plurality of water engagement device actuators receive the second signal output and, in response thereto, automatically generate a change in the water engagement device delta position to counter a roll motion resulting from a steering position change.
5. The system of claim 3, wherein the bias is a minimum bias associated with a change in speed of the marine vessel.
6. The system of claim 1, wherein the software module comprises at least one embedded microprocessor and the control strategy is implemented by a command looping saturation control algorithm comprising at least one set of program instructions; and wherein the at least one embedded microprocessor is further configured to run the at least one set of program instructions in order for the software module to iteratively read, interpret and manipulate data associated with the operation of the marine vessel.
7. The system of claim 6, wherein the command looping saturation control algorithm is enabled to read input from an operator and automatically command a desired delta position for the at least one pair of water engagement devices by iteratively (a) determining the current delta position of the at least one pair of water engagement devices and (b) changing the deployed position of the at least one of the water engagement devices from the at least one pair of water engagement devices in order to align the deployment of the at least one pair of water engagement devices to the command generated from the input of the operator.
8. The system of claim 7, wherein the operator input comprises of a delta command and the change in the deployed position of the at least one of the water engagement devices from the at least one pair of water engagement devices comprises maintaining, increasing or reducing the deployed position in response to the delta command.
9. The system of claim 8, wherein the at least one set of program instructions of the command looping saturation control algorithm is configured and enabled to iteratively: (a) loop any reading of a negative command data generated for a minimum bias of the at least one pair of water engagement devices; (b) invert the sign of the negative command data and convert it to a positive command data; and (c) add the converted positive command data to the at least one of the water engagement devices from the at least one pair of water engagement devices that is attempting to increase its deployed position in response to the operator command.
10. A method of dynamic active control of a marine vessel, the method comprising the steps of: mounting a plurality of water engagement devices adjacent a transom of the marine vessel, wherein each of the water engagement devices includes an actuator and a blade connected to the actuator; connecting a software module having an embedded microprocessor-based control system to (1) a plurality of sensors and (2) each of the water engagement devices, wherein the plurality of sensors comprises at least one inertial sensor; commanding activation of the actuator and deployment of the blade in response thereto based on data received from the plurality of sensors and a desired setting; and implementing a command looping saturation control strategy within the software module including further activation of the actuators to generate a steady water engagement device delta position when one of the water engagement devices reaches a pre-determined level of bias; measuring data received from the at least one inertial sensor that is representative of motion of the vessel; and implementing further the command looping saturation control strategy within the software module to iteratively (a) one of reduce drag and maximize a roll performance of the marine vessel and (b) provide real-time stability of the marine vessel based on the measuring step.
11. The method of claim 10, wherein the level of bias is a threshold of one of a depth of deployment of the one of the water engagement devices and a speed of deployment of the one of the water engagement devices as a function of the data received from the plurality of sensors related to a speed of the marine vessel.
12. The method of claim 10, further comprising: embedding an adjustable steering position control within the engine control module; providing a first signal output to the plurality of water engagement device actuators to command a water engagement device delta position in order to combat dynamic motions of the marine vessel; measuring a relationship between the water engagement device delta position and, in response thereto, provides a second signal output to the plurality of water engagement device actuators; and receiving the second signal output by the plurality of water engagement device actuators and, in response thereto, automatically generating a change in the water engagement device delta position to counter a roll motion resulting from a steering position change.
13. The method of claim 10, wherein the command looping saturation control strategy is enabled to read input from an operator and automatically command a desired delta position for the at least one pair of water engagement devices by iteratively (a) determining the current delta position of the at least one pair of water engagement devices and (b) changing the deployed position of the at least one of the water engagement devices from the at least one pair of water engagement devices in order to align the deployment of the at least one pair of water engagement devices to the command generated from the input of the operator.
14. The method of claim 13, wherein the operator input comprises of a delta command and the change in the deployed position of the at least one of the water engagement devices from the at least one pair of water engagement devices comprises maintaining, increasing or reducing the deployed position in response to the delta command.
15. The method of claim 14, wherein the at least one set of program instructions of the command looping saturation control strategy is configured and enabled to iteratively: (a) loop any reading of a negative command data generated for a minimum bias of the at least one pair of water engagement devices; (b) invert the sign of the negative command data and convert it to a positive command data; and (c) add the converted positive command data to the at least one of the water engagement devices from the at least one pair of water engagement devices that is attempting to increase its deployed position in response to the operator command.
16. A dynamic active control system, the system comprising: a marine vessel, a software module, a plurality of sensors and a plurality of water engagement devices, wherein the plurality of water engagement devices are connected to the marine vessel adjacent a transom of the marine vessel, wherein each of the water engagement devices includes an actuator and a blade connected to the actuator, wherein the software module is communicatively and operatively connected to the plurality of sensors and to each water engagement device to iteratively command activation of the actuator and deployment of the blade in response thereto based on data received from the plurality of sensors and a desired setting, wherein the software module includes a control strategy that iteratively generates a consistent water engagement device delta position when at least one of the water engagement devices is disposed at a pre-determined level of bias, and wherein the software module further includes an autopilot heading control strategy including a feedback loop and an actuator connected to an engine in communication with an engine control.
17. The system of claim 16, wherein the control strategy comprises a command looping saturation control algorithm enabled to read input from an operator and automatically command a desired delta position for the at least one pair of water engagement devices by iteratively (a) determining the current delta position of the at least one pair of water engagement devices and (b) changing the deployed position of the at least one of the water engagement devices from the at least one pair of water engagement devices in order to align the deployment of the at least one pair of water engagement devices to the command generated from the input of the operator.
18. The system of claim 17, wherein the command looping saturation control algorithm is configured and enabled to iteratively: (a) loop any reading of a negative command data generated for a minimum bias of the at least one pair of water engagement devices; (b) invert the sign of the negative command data and convert it to a positive command data; and (c) add the converted positive command data to the at least one of the water engagement devices from the at least one pair of water engagement devices that is attempting to increase its deployed position in response to the operator command.
19. The system of claim 18, the system further comprising a total pitch axis control strategy including symmetric deployment of a plurality of water engagement devices at a deployment speed of at least 100 mm/s while simultaneously adjusting an engine trim actuator; a total roll and heading control strategy including a differential deployment of the plurality of water engagement devices at a deployment speed of at least 100 mm/s to counter a measured rolling motion while simultaneously adjusting a steering actuator to counter a measured yaw motion resulting from the differential deployment and adjusting the steering actuator to counter the measured yaw motion generated by a gyroscopic stabilization device adapted to be installed within the marine vessel; wherein the software module is further configured and enabled with a command looping saturation control algorithm in order to iteratively (a) reduce drag and/or maximize the roll performance of a marine vessel and (b) provide real-time ride stability of the marine vessel by delivering consistent water engagement device delta position when at least one of the water engagement devices is at a certain pre-determined bias; and wherein the software module is further configured and enabled with a an autopilot heading control algorithm comprising a feedback loop and a means of actuation.
20. The system of claim 16, the system comprising: a software module including an embedded microprocessor-based control system, a multi-axis rate sensor and a steering position sensor operatively connected to at least one of the water engagement devices and to the software module; wherein the control system determines an asymmetric deployment of the at least one of the water engagement devices in response to a dynamic roll axis motion measured by the rate sensor as a result of a change in an output from the steering position sensor; wherein the control system determines a relationship between the output from the steering position sensor and the asymmetric controller deployment; and wherein the control system automatically commands changes to the asymmetric controller deployment to counter the dynamic roll axis motion resulting from the change in the output from the steering position sensor.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present disclosure and, together with the description, serve to explain the principles of the embodiments. In the drawings:
[0027]
[0028]
[0029]
[0030]
[0031]
DETAILED DESCRIPTION OF THE DISCLOSURE
[0032] For the purposes of promoting and understanding the principles disclosed herein, reference is now made to the preferred embodiments illustrated in the drawings, and specific language is used to describe the same.
[0033] As illustrated in
[0034] Referring back to
[0035] The software module 202communicatively coupled to the engine control module 302 of the engine of the marine vessel 2000is further configured to a provide power, communications and/or data to the actuators for fast deployment of the WEDs 602, 606. Further, as illustrated in
[0036] As illustrated in the DACS 1000 disclosed herein, the distribution module 400 may be mounted and located in proximity to the transom of the marine vessel 2000 wherein the operational console 200 (including the software module 202) may be mounted near the helm and not in proximity to the transom of the marine vessel 2000. The various modules are communicatively coupled to each otherspecifically the engine control module 302, the software module 202, and the actuators for the WEDs (602, 606)via industry standard power and communication cables. The WED may be mounted on or near the transom of the marine vesselthe WED actuator may be configured to provide fast deployment of the WEDs in 100 mm/s or more (mm/s)preferably faster than 250 mm/s. During operation of the marine vessel 2000, the system 1000 is further designed to generate signalsfor example, a wake signalfor the software module 202 to communicate a power on (wake up) status to the various components of the systemnamely, the engine-control module 302 and other components (displays, input devices etc.) of the operational console 200 and the actuators for fast deployment of the WEDs 602, 606.
[0037] Referring back to
[0038] The software module 202 further comprises a plurality of multi-axis inertial sensors for measuring rates or acceleration generated along multiple vector axes during the operation of the marine vessel 2000. The software module 202 is configured to be communicatively and operatively connected to the plurality of multi-axis inertial sensorsincluding, for example, the accelerometer sensors for measuring accelerations along the x, y and z axes (longitudinal acceleration, lateral acceleration and vertical acceleration), sensors to measure the roll rate, pitch rate and yaw rateRoll Rate Sensor (RRS), Pitch Rate Sensor (PRS) and Yaw Rate Sensor (YRS), respectively. This disclosure also include embodiments that include 6-axis, 9-axis or magnetometer sensors or other similar sensors for various measurementse.g., rates, accelerations, forces, torques etc.generated during the dynamic active control of the vessel. The software module 202 communicatively connected to the WEDs 602, 606 can be programmed to act (make certain iterative decisions) based on information received from an attitude sensor (e.g., pitch and roll) as well as from a global positioning system (GPS) sensor located at a pre-selected fixed position on the marine vessel 2000.
[0039] Referring back to
[0040] As illustrated in
[0041] In another aspect of the present disclosure, during operation of the marine vessel 2000, the system 1000 continuously monitors and measures data/feedback from the sensors and send command signals to instruct the actuator systems for fast deployment of WEDs 602, 606 to counteract certain dynamic active motions of the marine vessel (e.g., motions in the 0-3 Hz frequency spectrum across the roll, yaw and pitch axes) and provide the required dynamic active control of the marine vessel.
[0042] In another aspect of the present disclosure, DACS 1000 as disclosed herein is configured to make the necessary adjustment to the engine steering angle to control the heading of the marine vessel 2000 and counter the resulting heading change resulting from WED delta position. The DACS 1000 can measure a change in steering position and predict the resulting roll motion generated from the steering position change while automatically generating WED delta position to counter the roll motion that will ultimately result from this steering position change.
[0043] In another aspect of the present disclosure, the DACS 1000 is configured to adjust the vessel 2000 trim angle by symmetric deployment (shown in
[0044] In yet another aspect of the present disclosure, the software module 202 is further configured with a Safe Blade Deployment Limit (SBDL) control strategy configured to read and interpret data from a marine vessel acceleration/deceleration vs. blade deployment curve, the contents of which are embedded within the proprietary programs of the software module 202. As discussed above, the software module includes a control strategy that further iteratively commands activation of the actuators to generate a water engagement device delta position when one of the water engagement devices reaches a pre-determined threshold of one of a depth of deployment of the one of the water engagement devices and a speed of deployment of the one of the water engagement devices as a function of the data received from the plurality of sensors related to a speed of the marine vessel.
[0045] The smart proprietary control software strategy primarily drives the SBDL to continuously read, measure and interpret the datain a continuous loopand control or limit the depth of deployment and/or speed of deploymentthe biasof the water engagement devices at various speeds during operation of the marine vessel. The novel and unique SBDL can vary bias if the vessel 2000 is accelerating or decelerating by controlling the bias as a set function of the speed of the marine vessel 2000. For instance, if the vessel 2000 accelerates while traveling at a speed of 25 mphthe bias of the water engagement device could be at 1 inch. However, if the vessel 2000 decelerates while traveling at 25 mph, the SBDL could limit the bias to 0.5 inch (instead of the 1 inch).
[0046] In still yet another aspect of the present disclosure, the DACS disclosed herein provides for at least two optimization strategies by allowing the DACS to be controlled by the WED average position as well as by the engine trim. The DACS is configured to receive a desired trim angle from the operator and adjust the average positions of the WEDs as well as the engine trim angle in an effort to achieve the operator's desired trim angle. As disclosed herein, the DACS is configured to adjust the relationship between engine trim and WED average position, and optimize either the performance of the DACS system or fuel efficiency of the engine.
[0047] In another aspect of the present disclosure, during operation as the marine vessel 2000 moves through the water the system 1000 is configured to adjust the engine steering position to counter the yaw moment (by measuring the changing drag force) associated with the WEDs 602, 606 delta deployment. The software module 202 can provide a signal to the engine control module 302 of the engine for adjusting the steering position of the engine.
[0048] Referring back to
[0049] In another embodiment, during operation of the marine vessel 2000, a total roll axis control system generates a delta position between WEDs on the port and starboard side of the vessel in order to generate an anti-rolling torquethe anti-rolling torque used to combat roll motion of the marine vessel 2000 induced by waves, weight imbalances, or other causes. During such an event, the delta position increases the deployment command for one WED (e.g., 602) and decreases the deployment command (or retracts) for the other WED (e.g., 606). The WED delta is proportional to the rolling motion and generally the more deployed the WEDs the higher is the average position of the WEDs. The generation of higher bias in turn results in reduction or decrease in the trim angle of the marine vessel 2000. In certain situations, during boating, an operator might want the highest possible trim angle for the vessel 2000 which in turn generates the minimum possible bias command to the WEDs (602, 606). Once the WED bias is at its minimumthe controller attempts to combat rolling motions of the vessel 2000 by increasing the delta position between the WEDs on the port and starboard side. However, for optimum performancein order to increase delta position while having the minimum possible impact on biasone WED must increase its deployed position while the other WED must decrease its deployed position (or otherwise retract). In such a situationthe performance of the vessel 2000 could get affected. For example, when bias is already at minimumthe deployment position of the WED cannot be further decreased and thereby failing to achieve desired anti-rolling torque.
[0050] As disclosed herein, in order to overcome such drawbacks, the software module 202 is configured with a novel and unique command looping saturation strategySaturation Strategyto further stabilize operation of the marine vessel 2000. The Saturation Strategy can (a) reduce drag and/or maximize roll performance; and (b) provide real-time ride marine stability by mitigating roll motions while maintaining dynamic active control of the vessel 2000, as further explained herein. The novel command looping saturationSaturation Strategy loops the negative command meant for the WED at minimum position, inverts its sign, adds it to the WED that is increasing its positionthe command looping saturation therefore delivering the desired WED delta position despite the minimum bias command generated for the WEDs, as shown in
[0051] As further illustrated in the
[0052] The Saturation Strategy controls optimal deployment of the WEDsfrom a fully deployed position (shown in
[0053] In another aspect of the present disclosure, the software module 202 is can receive and process data on the steering position of the engine of the marine vessel 2000. Specifically, the processor is programmed to measure the relationship between the steering position of the engine and the WED 602, 606 delta position. Based on the measured data, the software module 202 can generate and send predictive signals to the actuator to adjust the WEDs 602, 606 by differentially deploying each of the WEDs 602, 606 to counter rolling motions and simultaneously adjust the engine steering position to counter the steering moment associated with the WED delta position, as shown in
[0054] In another aspect of the present disclosure, the DACS 1000 provides the operator with the option to control and change (if necessary) the commanded roll angle of the marine vessel 2000. During operation of the marine vessel 2000, if waves hit a boat on the starboard side the operator has the option to dynamically change the commanded roll angle and/or instruct the operator via the user interfaces of to tilt the boat down to the port side.
[0055] The processing and computing of the dataspecifically the processing of signal by the software module 202 to change the deployment angles of the WEDs/Controllers 602, 606 based on the difference between the commanded and the actual (measured) roll angle, is one of the key innovative features of the improved DACS. An operator can change the commanded roll angle (e.g., 5 to 5 degrees) which triggers the decision loop within the control system and generates the output signal to instruct the actuator system for fast (at 100 mm/s or more) delta deployment of the WEDs 602, 606.
[0056] It is understood that the preceding is merely a detailed description of some examples and embodiments of the present disclosure, and that numerous changes to the disclosed embodiments may be made in accordance with the disclosure made herein without departing from the spirit or scope of the disclosure. The preceding description, therefore, is not meant to limit the scope of the disclosure, but to provide sufficient disclosure to allow one of ordinary skill in the art to practice the disclosure without undue burden. It is further understood that the scope of the present disclosure fully encompasses other embodiments that may become obvious to those skilled in the art.
[0057] Differential and differentially are defined within this document as unequal, off center and/or involving differences in: angle, speed, rate, direction, direction of motion, output, force, moment, inertia, mass, balance, application of comparable things, etc. The terms Dynamic and/or Dynamic Active Control may mean the immediate action that takes place at the moment they are needed. Any use of the term immediate, in this application, means that the control action occurs in a manner that is responsive to the extent that it prevents or mitigates vessel motions and attitudes before they would otherwise occur in the uncontrolled situation. A person of ordinary skilled in the art understands the relationship between sensed motion parameters and required response in terms of the maximum overall delay that can exist while still achieving the control objectives. Dynamic and/or Dynamic Active Control may be used in describing interactive hardware and software systems involving differing forces and may be characterized by continuous change and/or activity. Dynamic may also be used when describing the interaction between a vessel and the environment. As stated above, marine vessels may be subject to various dynamic forces generated by its propulsion system as well as the environment in which it operates. Any reference to vessel attitude may be defined as relative to three rotational axes including pitch attitude or rotation about the Y, transverse or sway axis, roll attitude or rotation about the X, longitudinal or surge axis, and yaw attitude or rotation about the Z, vertical or heave axis.
[0058] Various features of the example embodiments described herein may be implemented using hardware, software, or a combination thereof and may be implemented in one or more computer systems or other processing systems. However, the manipulations performed in these embodiments were often referred to in terms, such as determining, which are commonly associated with mental operations performed by a human operator. No such capability of a human operator is necessary in any of the operations described herein. Rather, the operations may be completely implemented with machine operations. Useful machines for performing the operation of the exemplary embodiments presented herein include general purpose digital computers or similar devices. With respect to hardware, a CPU typically includes one or more components, such as one or more microprocessors for performing the arithmetic and/or logical operations required for program execution, and storage media, such as one or more disk drives or memory cards (e.g., flash memory) for program and data storage, and a random access memory for temporary data and program instruction storage. With respect to software, a CPU typically includes software resident on a storage media (e.g., a disk drive or memory card), which, when executed, directs the CPU in performing transmission and reception functions.
[0059] The CPU software may run on an operating system stored on the storage media, such as, for example, UNIX or Windows (e.g., NT, XP, Vista), Linux, and the like, and can adhere to various protocols such as the Ethernet, ATM, TCP/IP, CAN, LIN protocols and/or other connection or connectionless protocols. As is known in the art, CPUs can run different operating systems, and can contain different types of software, each type devoted to a different function, such as handling and managing data/information from a particular source, or transforming data/information from one format into another format. It should thus be clear that the embodiments described herein are not to be construed as being limited for use with any particular type of server computer, and that any other suitable type of device for facilitating the exchange and storage of information may be employed instead.
[0060] A CPU may be a single CPU, or may include multiple separate CPUs, wherein each is dedicated to a separate application, such as, for example, a data application, a voice application, and a video application. Software embodiments of the example embodiments presented herein may be provided as a computer program product, or software, that may include an article of manufacture on a machine-accessible or non-transitory computer-readable medium (i.e., also referred to as machine readable medium) having instructions. The instructions on the machine-accessible or machine-readable medium may be used to program a computer system or other electronic device. The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, CD-ROMs, magneto-optical disks, USB thumb drives, and SD cards or other type of media/machine-readable medium suitable for storing or transmitting electronic instructions. The techniques described herein are not limited to any particular software configuration. They may find applicability in any computing or processing environment. The terms machine-accessible medium, machine-readable medium, and computer-readable medium used herein shall include any non-transitory medium that is capable of storing, encoding, or transmitting a sequence of instructions for execution by the machine (e.g., a CPU or other type of processing device) and that cause the machine to perform any one of the methods described herein. It is to be noted that it is commonas a person skilled in the art can contemplatein the art to speak of software, in one form or another (e.g., program, procedure, process, application, module, unit, logic, and so on) as taking an action or causing a result. Such expressions are merely a shorthand way of stating that the execution of the software by a processing system causes the processor to perform an action to produce a result.
[0061] The use of the terms a and an and the and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms comprising, having, including, and containing are to be construed as open-ended terms (i.e., meaning including, but not limited to,) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
[0062] The use of any and all examples, or exemplary language (e.g., such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. It is understood that the preceding is merely a detailed description of some examples and embodiments of the present disclosure, and that numerous changes to the disclosed embodiments may be made in accordance with the disclosure made herein without departing from the spirit or scope of the disclosure. The preceding description, therefore, is not meant to limit the scope of the disclosure, but to provide sufficient disclosure to allow one of ordinary skill in the art to practice the disclosure without undue burden.
[0063] It is further understood that the scope of the present disclosure fully encompasses other embodiments that may become obvious to those skilled in the art. Features illustrated or described as part of one embodiment can be used in another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure cover such modifications and variations as come within the scope of the appended claims and their equivalents. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present disclosure, which broader aspects are embodied in the exemplary constructions.