阅读说明：本技术 一种无人机飞行控制方法、系统、装置及存储介质 (Unmanned aerial vehicle flight control method, system, device and storage medium ) 是由 梁亚东 罗飞 于 2021-08-03 设计创作，主要内容包括：本发明公开了一种无人机飞行控制方法、系统及装置。该方法包括以下步骤：获取无人机飞行前方的障碍物信息；根据所述障碍物信息生成避障轨迹；根据偏差参数确定所述避障轨迹的飞行速度,所述偏差参数包括所述无人机飞行航向与所述避障轨迹的夹角偏差以及夹角偏差变化量。通过使用本发明中的方法,能够根据偏差参数控制无人机避障时的飞行速度,可以有效防止无人机避障飞行时因为惯性发生侧向偏移或失控,解决了无人机避障飞行时的鲁棒性不强的问题。本发明可广泛应用于一种无人机技术领域内。(The invention discloses a flight control method, system and device for an unmanned aerial vehicle. The method comprises the following steps: acquiring barrier information in front of the flight of the unmanned aerial vehicle; generating an obstacle avoidance track according to the obstacle information; and determining the flight speed of the obstacle avoidance track according to deviation parameters, wherein the deviation parameters comprise the included angle deviation and the included angle deviation variable quantity of the flight course of the unmanned aerial vehicle and the obstacle avoidance track. By using the method, the flight speed of the unmanned aerial vehicle during obstacle avoidance can be controlled according to the deviation parameters, the unmanned aerial vehicle can be effectively prevented from generating lateral deviation or out of control due to inertia during obstacle avoidance flight, and the problem of poor robustness during obstacle avoidance flight of the unmanned aerial vehicle is solved. The invention can be widely applied to the technical field of unmanned aerial vehicles.)

1. An unmanned aerial vehicle flight control method is characterized by comprising the following steps:

acquiring barrier information in front of the flight of the unmanned aerial vehicle;

generating an obstacle avoidance track according to the obstacle information;

and determining the flight speed of the obstacle avoidance track according to deviation parameters, wherein the deviation parameters comprise the included angle deviation and the included angle deviation variable quantity of the flight course of the unmanned aerial vehicle and the obstacle avoidance track.

2. The method of claim 1, wherein the step of determining the flight speed of the obstacle avoidance trajectory according to the deviation parameter comprises the steps of:

acquiring the deviation parameter;

inputting the deviation parameter to a fuzzy controller, and outputting the flying speed by the fuzzy controller; the fuzzy controller is used for adjusting the flight speed of the unmanned aerial vehicle on the obstacle avoidance track.

3. The method of claim 2, further comprising the step of constructing the fuzzy controller, the step of constructing the fuzzy controller comprising the steps of:

determining the fuzzy quantity of the deviation parameter, and taking the fuzzy quantity of the deviation parameter as the input of the fuzzy controller;

determining a target flight speed corresponding to the deviation parameter, and taking the fuzzy quantity of the target flight speed as the output of a fuzzy controller;

creating a fuzzy control rule base according to the input of the fuzzy controller and the output of the fuzzy controller;

and extracting the fuzzy control rule of the fuzzy control rule base, and obtaining the fuzzy controller according to the fuzzy control rule.

4. The method of claim 1, further comprising the steps of:

and carrying out smoothing treatment on the obstacle avoidance track.

5. The unmanned aerial vehicle flight control method according to claim 2, wherein the obstacle avoidance trajectory comprises N trajectory line segments, N is a natural number and N is greater than or equal to 1, and the step of smoothing the obstacle avoidance trajectory comprises the following steps:

step A, determining an included angle between the track line segment of the ith segment and the track line segment of the (i + 1) th segment as a first included angle theta 1, wherein i +1 is less than or equal to N;

b, determining that the first included angle theta 1 is larger than or equal to an angle threshold value, increasing i by 1, and returning to execute the step A if i is increased by 1 and is smaller than or equal to N;

step C, if the first included angle theta 1 is determined to be smaller than the angle threshold, the middle points M1 and M2 of two line segments adjacent to the first included angle theta 1 are obtained; determining a transition line segment according to the midpoints M1 and M2;

d, determining that a second included angle theta 2 between the transition line segment and the ith track line segment and a third included angle theta 3 between the transition line segment and the (i + 1) th track line segment are both larger than an angle threshold, reserving the transition line segment, increasing i by 1, and returning to execute the step A, wherein the i is increased by 1 and is less than or equal to N;

step E, determining that at least one of the second included angle theta 2 and the third included angle theta 2 is smaller than an angle threshold value, returning to execute the step C to judge the second included angle theta 2 and/or the third included angle theta 3;

step F, i increases 1, and i is increased by 1 and then is less than or equal to N, then returns to execute step A, otherwise, finishes executing the smoothing processing.

6. An unmanned aerial vehicle flight control system, comprising:

the obstacle information acquisition module is used for acquiring obstacle information in front of the flight of the unmanned aerial vehicle;

the track generation module is used for generating an obstacle avoidance track according to the obstacle information;

and the control module is used for determining the flight speed of the obstacle avoidance track according to deviation parameters, and the deviation parameters comprise the flight course of the unmanned aerial vehicle, the included angle deviation of the obstacle avoidance track and the included angle deviation variable quantity.

7. The drone flight control system of claim 6, further comprising:

and the track optimization module is used for carrying out smoothing processing on the obstacle avoidance track.

8. An unmanned aerial vehicle flight control device, its characterized in that includes:

at least one processor;

at least one memory for storing at least one program;

when executed by the at least one processor, cause the at least one processor to implement a drone flight control method according to any one of claims 1-5.

9. A storage medium having stored therein a program executable by a processor, characterized in that: the processor executable program when executed by the processor is for implementing a drone flight control method as claimed in any one of claims 1 to 5.

Technical Field

The invention relates to the technical field of unmanned aerial vehicles, in particular to a flight control method, a flight control system, a flight control device and a storage medium for an unmanned aerial vehicle.

Background

Unmanned aerial vehicle can survey surrounding environment at the flight in-process, when detecting the barrier, can generate one in advance and keep away the barrier orbit, and unmanned aerial vehicle bypasses the barrier according to the orbit that generates.

However, when the obstacle is bypassed according to the obstacle avoidance trajectory, the flight speed is difficult to control, and the flight speed is fast, so that the obstacle avoidance turning is not robust due to the fact that the lateral deviation or the runaway condition occurs easily due to inertia.

Disclosure of Invention

The present invention aims to solve at least to some extent one of the technical problems existing in the prior art.

Therefore, an object of the embodiments of the present invention is to provide a flight control method for an unmanned aerial vehicle, which can effectively prevent the unmanned aerial vehicle from generating lateral deviation or runaway due to inertia when the unmanned aerial vehicle is in obstacle avoidance flight, and improve robustness when the unmanned aerial vehicle is in obstacle avoidance flight.

According to a first aspect of the embodiments of the present application, there is provided a flight control method for an unmanned aerial vehicle, including the following steps:

acquiring barrier information in front of the flight of the unmanned aerial vehicle;

generating an obstacle avoidance track according to the obstacle information;

and determining the flight speed of the obstacle avoidance track according to deviation parameters, wherein the deviation parameters comprise the included angle deviation and the included angle deviation variable quantity of the flight course of the unmanned aerial vehicle and the obstacle avoidance track.

Further, the step of determining the flight speed of the obstacle avoidance trajectory according to the deviation parameter includes the following steps:

acquiring the deviation parameter;

and inputting the deviation parameters into a fuzzy controller, and outputting the flying speed by the fuzzy controller, wherein the fuzzy controller is used for adjusting the flying speed of the unmanned aerial vehicle on the obstacle avoidance track.

Further, the unmanned aerial vehicle flight control method further comprises the step of constructing the fuzzy controller, and the step of constructing the fuzzy controller comprises the following steps:

determining the fuzzy quantity of the deviation parameter, and taking the fuzzy quantity of the deviation parameter as the input of the fuzzy controller;

determining a target flight speed corresponding to the deviation parameter, and taking the fuzzy quantity of the target flight speed as the output of a fuzzy controller;

creating a fuzzy control rule base according to the input of the fuzzy controller and the output of the fuzzy controller;

and extracting the fuzzy control rule of the fuzzy control rule base, and obtaining the fuzzy controller according to the fuzzy control rule.

Further, the unmanned aerial vehicle flight control method further comprises the following steps:

and carrying out smoothing treatment on the obstacle avoidance track.

Further, the obstacle avoidance track comprises N track line segments, N is a natural number and N is greater than or equal to 1, and the step of performing smoothing on the obstacle avoidance track includes the following steps:

step A, determining an included angle between the track line segment of the ith segment and the track line segment of the (i + 1) th segment as a first included angle theta 1, wherein i +1 is less than or equal to N;

b, determining that the first included angle theta 1 is larger than or equal to an angle threshold value, increasing i by 1, and returning to execute the step A if i is increased by 1 and is smaller than or equal to N;

step C, if the first included angle theta 1 is determined to be smaller than the angle threshold, the middle points M1 and M2 of two line segments adjacent to the first included angle theta 1 are obtained; determining a transition line segment according to the midpoints M1 and M2;

d, determining that a second included angle theta 2 between the transition line segment and the ith track line segment and a third included angle theta 3 between the transition line segment and the (i + 1) th track line segment are both larger than an angle threshold, reserving the transition line segment, increasing i by 1, and returning to execute the step A, wherein the i is increased by 1 and is less than or equal to N;

step E, determining that at least one of the second included angle theta 2 and the third included angle theta 2 is smaller than an angle threshold value, returning to execute the step C to judge the second included angle theta 2 and/or the third included angle theta 3;

step F, i increases 1, and i is increased by 1 and then is less than or equal to N, then returns to execute step A, otherwise, finishes executing the smoothing processing.

According to a first aspect of the embodiments of the present application, there is provided an unmanned aerial vehicle flight control system, including:

the obstacle information acquisition module is used for acquiring obstacle information in front of the flight of the unmanned aerial vehicle;

the track generation module is used for generating an obstacle avoidance track according to the obstacle information;

and the control module is used for determining the flight speed of the obstacle avoidance track according to deviation parameters, and the deviation parameters comprise the flight course of the unmanned aerial vehicle, the included angle deviation of the obstacle avoidance track and the included angle deviation variable quantity.

According to a third aspect of the embodiments of the present application, there is provided an unmanned aerial vehicle flight control device, including:

at least one processor;

at least one memory for storing at least one program;

when executed by the at least one processor, cause the at least one processor to implement the method for flight control of a drone.

According to a fourth aspect of embodiments of the present application, there is provided a storage medium having stored therein a processor-executable program, which when executed by a processor, is configured to implement a method for flight control of a drone.

Advantages and benefits of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention:

the embodiment of the invention can control the flight speed of the unmanned aerial vehicle during obstacle avoidance according to the deviation parameter, can effectively prevent the unmanned aerial vehicle from generating lateral deviation or out of control due to inertia during obstacle avoidance flight, and solves the problem of poor robustness during obstacle avoidance flight of the unmanned aerial vehicle.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description is made on the drawings of the embodiments of the present invention or the related technical solutions in the prior art, and it should be understood that the drawings in the following description are only for convenience and clarity of describing some embodiments in the technical solutions of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic flow chart of a flight control method for an unmanned aerial vehicle according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an embodiment of a flight control system of an unmanned aerial vehicle according to the present invention;

fig. 3 is a schematic structural diagram of an embodiment of the flight control device of an unmanned aerial vehicle according to the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention. The step numbers in the following embodiments are provided only for convenience of illustration, the order between the steps is not limited at all, and the execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

A method, a system, an apparatus, and a storage medium for controlling flight of an unmanned aerial vehicle according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and first, a method for controlling flight of an unmanned aerial vehicle according to embodiments of the present invention will be described with reference to the accompanying drawings.

Referring to fig. 1, the flight control method of the unmanned aerial vehicle in the embodiment of the present invention mainly includes the following steps:

s1: acquiring barrier information in front of the flight of the unmanned aerial vehicle;

in particular, the obstacles include dynamic obstacles and static obstacles, for example, a flying bird may be a dynamic obstacle and other hovering drones may be static obstacles.

And detecting the surrounding environment of the unmanned aerial vehicle in real time by using a sensor, and acquiring the speed information and the position information of the barrier in real time. For example, can adopt laser radar to acquire the barrier information in unmanned aerial vehicle flight the place ahead, can install three laser radar on unmanned aerial vehicle's base for obtain the barrier information at the dead ahead of direction of flight, the 45 degrees angles on the left side and the 45 degrees angles on the right. The unmanned aerial vehicle can calculate the direction information of the obstacle relative to the unmanned aerial vehicle according to the acquired position information of the obstacle and the position information of the unmanned aerial vehicle.

S2: generating an obstacle avoidance track according to the obstacle information;

specifically, after the unmanned aerial vehicle detects the obstacle, the obstacle avoidance track is generated immediately according to the obstacle information, and the unmanned aerial vehicle flies according to the pre-generated obstacle avoidance track, so that the purpose of obstacle avoidance is achieved. The obstacle avoidance trajectory may be generated using path generation algorithms in the prior art.

S3: and determining the flight speed of the obstacle avoidance track according to deviation parameters, wherein the deviation parameters comprise the deviation included angle between the flight course of the unmanned aerial vehicle and the obstacle avoidance track and the variation of the deviation included angle.

Specifically, the deviation parameter includes an angle deviation and a deviation included angle variation between a flight direction in which the unmanned aerial vehicle advances and a pre-planned obstacle avoidance track, and the deviation included angle variation can reflect a bending degree of the obstacle avoidance track, for example, the current deviation included angle and the deviation included angle variation of the obstacle avoidance track are large, which indicates that the bending degree of the current road section is large, that is, the angle of the unmanned aerial vehicle around the curve is large, if the flight speed of the unmanned aerial vehicle is not controlled, the deviation or the time out of control occurs due to inertia in a large possibility, so the obstacle avoidance track at the current section should reduce the flight speed, so that the unmanned aerial vehicle smoothly flies through the obstacle avoidance track at the section.

Therefore, the flight speed of the unmanned aerial vehicle during obstacle avoidance is controlled according to the deviation parameters, so that the unmanned aerial vehicle can be effectively prevented from generating lateral deviation or being out of control due to inertia during obstacle avoidance flight, and the problem of poor robustness during obstacle avoidance flight of the unmanned aerial vehicle is solved.

Further as an alternative embodiment, step S3 includes the following steps S31-S32:

s31, obtaining deviation parameters;

and S32, inputting the deviation parameters into a fuzzy controller, and outputting the flying speed by the fuzzy controller, wherein the fuzzy controller is used for adjusting the flying speed of the unmanned aerial vehicle on the obstacle avoidance track.

Specifically, the present embodiment provides a specific embodiment that utilizes the deviation parameter to determine the flight speed of the drone, that is, utilizes the fuzzy controller to determine the flight speed of the drone corresponding to the deviation parameter.

The unmanned aerial vehicle obtains the deviation parameter and inputs the deviation parameter to the fuzzy controller, and the fuzzy controller calculates the flight speed corresponding to the current deviation parameter according to the input deviation parameter, namely determines the flight speed according to the bending degree of the flight track, so that the flight speed is always suitable for the current flight track.

Further as an optional implementation manner, the method further includes a step S4 of constructing the fuzzy controller, and the step S4 includes the following steps:

s41, determining the fuzzy quantity of the deviation parameter, and taking the fuzzy quantity of the deviation parameter as the input of the fuzzy controller;

s42, determining the target flight speed corresponding to the deviation parameter, and taking the fuzzy quantity of the target flight speed as the output of the fuzzy controller;

s43, creating a fuzzy control rule base according to the input of the fuzzy controller and the output of the fuzzy controller;

and S44, extracting fuzzy control rules of a fuzzy control rule base, and obtaining the fuzzy controller according to the fuzzy control rules.

Specifically, the process of constructing the fuzzy controller is substantially a process of acquiring a fuzzy control rule, and the acquired fuzzy control rule is used to determine an output fuzzy amount corresponding to the input fuzzy amount.

Firstly, fuzzifying deviation parameters and a target flight speed by adopting a triangular membership function, wherein the deviation parameters comprise a deviation included angle between the flight course of the unmanned aerial vehicle and an obstacle avoidance track and a deviation included angle variable quantity, so that the fuzzy quantity of the deviation included angle is determined to be E, the fuzzy quantity of the deviation included angle variable quantity is determined to be EC, and the fuzzy quantity of the target flight speed is determined to be U.

Then, a fuzzy control rule base is formulated according to the fuzzy quantity of the deviation included angle as E, the fuzzy quantity of the deviation included angle variation as EC and the fuzzy quantity of the flight speed as U, wherein the fuzzy control rule base is composed of a plurality of control rules, the control rules are summarized according to the control experience of people, and the fuzzy control rule base can also be described in a matrix table form, as shown in Table 1:

TABLE 1

Extracting fuzzy control rules according to a fuzzy control rule base, wherein the extracted fuzzy control rules are as follows:

R＝(E×EC)×U，

here, the fuzzy operation × means "take small".

After the fuzzy control rules contained in the fuzzy control rule base are obtained, namely the fuzzy controller is obtained, the extracted fuzzy control rules/fuzzy controller can be used for calculating the flight speed corresponding to the input deviation parameters in the later period.

U＊＝(E＊×EC＊)оR，

Wherein, o represents the synthesis of the fuzzy matrix, is similar to the product operation of the common matrix, the product operation is changed into 'getting small', and the addition operation is changed into 'getting large'.

Of course, the fuzzy controller inputs the fuzzified deviation parameter and outputs the fuzzified target flight speed, and the fuzzified target flight speed is subjected to deblurring processing, so that the target flight speed with an accurate numerical value can be obtained. Under the condition of the current deviation parameters, the unmanned aerial vehicle controls the flight speed of the unmanned aerial vehicle to be kept at the flight speed with an accurate numerical value, and the robustness of the unmanned aerial vehicle in obstacle avoidance and turning is improved.

As a further optional implementation, the flight control method of the unmanned aerial vehicle further includes the following steps:

and S5, carrying out smoothing treatment on the obstacle avoidance track.

Specifically, the obstacle avoidance path of the designed unmanned aerial vehicle can generate a corner or a peak at a high probability when the unmanned aerial vehicle turns, so that the unmanned aerial vehicle shakes or is out of control, therefore, the obstacle avoidance path of the unmanned aerial vehicle needs to be subjected to smoothing treatment, the curve of the processed obstacle avoidance path is smoother, and the target flight speed of the unmanned aerial vehicle can be acquired by calculating deviation parameters and acquiring the target flight speed of the unmanned aerial vehicle according to the deviation parameters in the later stage.

Further as an optional implementation manner, the obstacle avoidance track includes N track line segments, where N is a natural number and N is greater than or equal to 1, and step S5 includes the following steps:

step A, determining an included angle between the ith track line segment and the (i + 1) th track line segment as a first included angle theta 1, wherein i +1 is less than or equal to N;

step B, determining that the first included angle theta 1 is larger than or equal to an angle threshold value, increasing i by 1, and returning to execute the step A if i is increased by 1 and is smaller than or equal to N;

step C, if the first included angle theta 1 is determined to be smaller than the angle threshold, the middle points M1 and M2 of two line segments adjacent to the first included angle theta 1 are obtained; determining a transition line segment according to the midpoints M1 and M2;

d, determining that a second included angle theta 2 between the transition line segment and the ith track line segment and a third included angle theta 3 between the transition line segment and the (i + 1) th track line segment are both larger than an angle threshold, reserving the transition line segment, increasing i by 1, and returning to execute the step A, wherein the i is increased by 1 and is less than or equal to N;

step E, determining that at least one of the second included angle theta 2 and the third included angle theta 2 is smaller than an angle threshold value, returning to execute the step C to judge the second included angle theta 2 and/or the third included angle theta 3;

step F, i increases 1, and i is increased by 1 and then is less than or equal to N, then returns to execute step A, otherwise, finishes executing the smoothing processing.

Specifically, the generated obstacle avoidance path may have a section with a peak/corner, and therefore, a path smoothing process for eliminating the peak/corner is required for the generated obstacle avoidance path.

Dividing the obstacle avoidance path into a plurality of track line segments, and judging the included angle between two adjacent track line segments, namely a first included angle theta₁When the angle is smaller than the angle threshold, the peak/corner exists between the two sections of track routes, and path smoothing is needed, so that the first included angle theta is selected₁The midpoints M1 and M2 of two adjacent line segments connect M1 and M2 to determine a transition line segment L, which is the angle between the transition line segment and the two trajectory line segments if a new line segment, i.e., the second angle θ₂And a firstThree included angles theta₃Can be greater than or equal to the angle threshold, indicating that the transition segment can become part of the obstacle avoidance trajectory, thereby eliminating the spike/corner segments. When the second included angle theta is judged₂And third angle theta₃When at least one included angle is smaller than the angle threshold value, the included angle is continuously the second included angle theta₂And/or third included angle theta₃And finding a transition line segment until the current path track is smooth.

And when all the track line segments are judged, finishing the smoothing treatment of the obstacle avoidance path.

Next, a flight control system of an unmanned aerial vehicle proposed according to an embodiment of the present invention is described with reference to the drawings.

Fig. 2 is a schematic structural diagram of a flight control system of an unmanned aerial vehicle according to an embodiment of the present invention.

The system specifically comprises:

it can be seen that the contents in the foregoing method embodiments are all applicable to this system embodiment, the functions specifically implemented by this system embodiment are the same as those in the foregoing method embodiment, and the advantageous effects achieved by this system embodiment are also the same as those achieved by the foregoing method embodiment.

Referring to fig. 3, an embodiment of the present invention provides an unmanned aerial vehicle flight control apparatus, including:

at least one processor 301;

at least one memory 302 for storing at least one program;

the at least one program, when executed by the at least one processor 301, causes the at least one processor 301 to implement a drone flight control method.

Similarly, the contents of the method embodiments are all applicable to the apparatus embodiments, the functions specifically implemented by the apparatus embodiments are the same as the method embodiments, and the beneficial effects achieved by the apparatus embodiments are also the same as the beneficial effects achieved by the method embodiments.

In alternative embodiments, the functions/acts noted in the block diagrams may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Furthermore, the embodiments presented and described in the flow charts of the present invention are provided by way of example in order to provide a more thorough understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and in which sub-operations described as part of larger operations are performed independently.

Furthermore, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise stated to the contrary, one or more of the described functions and/or features may be integrated in a single physical device and/or software module, or one or more functions and/or features may be implemented in a separate physical device or software module. It will also be appreciated that a detailed discussion of the actual implementation of each module is not necessary for an understanding of the present invention. Rather, the actual implementation of the various functional modules in the apparatus disclosed herein will be understood within the ordinary skill of an engineer, given the nature, function, and internal relationship of the modules. Accordingly, those skilled in the art can, using ordinary skill, practice the invention as set forth in the claims without undue experimentation. It is also to be understood that the specific concepts disclosed are merely illustrative of and not intended to limit the scope of the invention, which is defined by the appended claims and their full scope of equivalents.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes programs for enabling a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable programs that can be considered for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with a program execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the programs from the program execution system, apparatus, or device and execute the programs. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the program execution system, apparatus, or device.

More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

In the foregoing description of the specification, reference to the description of "one embodiment/example," "another embodiment/example," or "certain embodiments/examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.