阅读说明：本技术 一种转向电机热保护控制方法及装置 (Steering motor thermal protection control method and device ) 是由 郑凌航 刘俊 田树新 吴德旭 于 2021-07-27 设计创作，主要内容包括：本发明公开了一种转向电机热保护控制方法及装置,其中所述方法包括：获取转向电机在预设的最大工作电流值状态下的运行的第一时长；判断第一时长是否大于预设的第一助力时长；第一助力时长为转向电机以最大工作电流值工作时所积累的热量,达到热保护温度值的时长；当第一时长大于第一助力时长时,根据预设的电流系数,控制转向电机的工作电流值降低至保护电流值；其中,电流系数为调整电流值的速率,保护电流值为转向电机工作时发热和散热平衡的电流值。本发明可避免转向电机因超过最大承受温度,而过热发生烧蚀或停止工作,保证了转向电机的工作稳定性,延长了使用寿命。(The invention discloses a steering motor thermal protection control method and a device, wherein the method comprises the following steps: acquiring a first running time of a steering motor in a preset maximum working current value state; judging whether the first time length is greater than a preset first assistance time length or not; the first power-assisted duration is the duration of heat accumulated when the steering motor works at the maximum working current value to reach a thermal protection temperature value; when the first time length is longer than the first power-assisted time length, controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work. The invention can avoid the ablation or stop work of the steering motor due to overheating caused by exceeding the maximum bearing temperature, ensure the working stability of the steering motor and prolong the service life.)

1. A steering motor thermal protection control method is characterized by comprising the following steps:

acquiring a first running time of a steering motor in a preset maximum working current value state;

judging whether the first time length is greater than a preset first assistance time length or not; the first power-assisted duration is the duration when the heat accumulated when the steering motor works at the maximum working current value reaches a thermal protection temperature value;

when the first time length is longer than the first power-assisted time length, controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work.

2. The method according to claim 1, wherein the controlling the operating current value of the steering motor to be reduced to a protection current value according to a preset current coefficient comprises:

controlling the working current value of the steering motor to be reduced to an intermediate current value according to the current coefficient, and monitoring a second time length of the steering motor running at the intermediate current value; the intermediate current value is greater than the protection current value;

judging whether the second time length is greater than a preset second boosting time length or not; the second power-assisted duration is the duration when the heat accumulated when the steering motor works at the intermediate current value reaches the maximum temperature value which can be borne by the steering motor;

and when the second duration is longer than a preset second power-assisted duration, controlling the working current value of the steering motor to be reduced to the protection current value according to the current coefficient.

3. The method of claim 1, wherein the magnitude of the current coefficient value decreases as the operating current of the steering motor decreases.

4. The method of claim 3, wherein the magnitude of the current coefficient value decreases linearly as the operating current of the steering motor decreases.

5. The method of claim 3, wherein the protection current value has a value range of: 10A to 40A.

6. A steering motor thermal protection control device, comprising:

the detection module is used for acquiring a first running time of the steering motor in a preset maximum working current value state;

the judging module is used for judging whether the first time length is greater than a preset first boosting time length; the first power-assisted duration is the duration when the heat accumulated when the steering motor works at the maximum working current value reaches a thermal protection temperature value;

the regulation and control module is used for controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient when the first time length is longer than the first power-assisted time length; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work.

7. The device of claim 6, wherein the regulatory module is further specifically configured to:

controlling the working current value of the steering motor to be reduced to an intermediate current value according to the current coefficient, and monitoring a second time length of the steering motor running at the intermediate current value; the intermediate current value is greater than the protection current value;

judging whether the second time length is greater than a preset second boosting time length or not; the second power-assisted duration is the duration when the heat accumulated when the steering motor works at the intermediate current value reaches the maximum temperature value which can be borne by the steering motor;

and when the second duration is longer than a preset second power-assisted duration, controlling the working current value of the steering motor to be reduced to the protection current value according to the current coefficient.

8. The apparatus of claim 6, wherein the magnitude of the current coefficient value decreases as the operating current of the steering motor decreases.

9. The apparatus of claim 8, wherein the magnitude of the current coefficient value decreases linearly as the operating current of the steering motor decreases.

10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 5.

Technical Field

The invention relates to the technical field of automobiles, in particular to a steering motor thermal protection control method and device.

Background

When a driver of the automobile operates the steering wheel, the steering motor is required to provide power assistance so as to reduce the operating force of the steering wheel. At present, the thermal protection of the motor generally requires that the thermal protection is not started before the motor is started for 15 cycles in place, and the thermal protection is to close the motor. In the prior art, the temperature of the motor is judged by detecting a temperature sensor of the motor, so that the motor is thermally protected. High temperature can be produced in the long-time work of motor, and too high temperature can cause the motor ablation. Generally, after 15 cycles, the motor will activate the thermal protection and turn off the boost. Under some extreme conditions, although the protection measure can meet the requirements of users, the steering motor can often work at a higher temperature, so that the service life of the steering motor is unstable, and the steering motor is easy to break down.

Therefore, in the prior art, the control strategy of the steering motor is too simple, the steering motor is easy to work at high temperature for a long time, and the service life of the steering motor is short.

Disclosure of Invention

In view of the above problems, the present invention provides a steering motor thermal protection control method and apparatus, which can prevent the steering motor from being overheated to ablate or stop working due to exceeding the maximum bearing temperature, ensure the working stability of the steering motor, and prolong the service life.

In a first aspect, the present application provides the following technical solutions through an embodiment:

a steering motor thermal protection control method comprises the following steps:

acquiring a first running time of a steering motor in a preset maximum working current value state; judging whether the first time length is greater than a preset first assistance time length or not; the first power-assisted duration is the duration when the heat accumulated when the steering motor works at the maximum working current value reaches a thermal protection temperature value; when the first time length is longer than the first power-assisted time length, controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work.

Optionally, the controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient includes:

controlling the working current value of the steering motor to be reduced to an intermediate current value according to the current coefficient, and monitoring a second time length of the steering motor running at the intermediate current value; the intermediate current value is greater than the protection current value; judging whether the second time length is greater than a preset second boosting time length or not; the second power-assisted duration is the duration when the heat accumulated when the steering motor works at the intermediate current value reaches the maximum temperature value which can be borne by the steering motor; and when the second duration is longer than a preset second power-assisted duration, controlling the working current value of the steering motor to be reduced to the protection current value according to the current coefficient.

Optionally, the magnitude of the current coefficient value decreases as the operating current of the steering motor decreases.

Optionally, the magnitude of the current coefficient value decreases linearly as the operating current of the steering motor decreases.

Optionally, the value range of the protection current value is as follows: 10A to 40A.

In a second aspect, based on the same inventive concept, the present application provides the following technical solutions through an embodiment:

a steering motor thermal protection control device comprising:

the detection module is used for acquiring a first running time of the steering motor in a preset maximum working current value state; the judging module is used for judging whether the first time length is greater than a preset first boosting time length; the first power-assisted duration is the duration when the heat accumulated when the steering motor works at the maximum working current value reaches a thermal protection temperature value; the regulation and control module is used for controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient when the first time length is longer than the first power-assisted time length; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work.

Optionally, the regulatory module is further specifically configured to:

controlling the working current value of the steering motor to be reduced to an intermediate current value according to the current coefficient, and monitoring a second time length of the steering motor running at the intermediate current value; the intermediate current value is greater than the protection current value; judging whether the second time length is greater than a preset second boosting time length or not; the second power-assisted duration is the duration when the heat accumulated when the steering motor works at the intermediate current value reaches the maximum temperature value which can be borne by the steering motor; and when the second duration is longer than a preset second power-assisted duration, controlling the working current value of the steering motor to be reduced to the protection current value according to the current coefficient.

Optionally, the magnitude of the current coefficient value decreases as the operating current of the steering motor decreases.

Optionally, the magnitude of the current coefficient value decreases linearly as the operating current of the steering motor decreases.

In a second aspect, based on the same inventive concept, the present application provides the following technical solutions through an embodiment:

a computer-readable storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method of any of the first aspects.

The embodiment of the invention provides a steering motor thermal protection control method and device, wherein a first time length of operation of a steering motor in a preset maximum working current value state is obtained; then, judging whether the first time length is greater than a preset first power-assisted time length or not; the first power-assisted duration is the duration of heat accumulated when the steering motor works at the maximum working current value to reach a thermal protection temperature value; when the first time length is longer than the first power-assisted time length, controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work. The control process can ensure that the working current value of the steering motor can be reduced to protect the working current when the steering motor reaches the thermal protection temperature value, and the protection current value is the current value of the steering motor with balanced heating and heat dissipation, so that the work of the steering motor can be continuously maintained under the protection current value, the steering motor is prevented from being overheated to ablate or stop working due to the fact that the maximum bearing temperature is exceeded, the working stability of the steering motor is ensured, and the service life is prolonged.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts. In the drawings:

FIG. 1 is a flow chart illustrating a steering motor thermal protection control method according to an embodiment of the present invention;

FIG. 2 is a diagram showing the variation of the current coefficient and the operating current in the embodiment of the present invention;

FIG. 3 illustrates a schematic diagram of steering motor heat accumulation in an embodiment of the present invention;

FIG. 4 is a schematic diagram showing a change in operating current of the steering motor in the embodiment of the present invention;

fig. 5 is a schematic structural diagram showing a steering motor thermal protection control device in an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The power of the steering motor of the household vehicle can reach as high as 600w, and when the steering motor works continuously for a long time, a large amount of heat can be generated, so that the temperature of the steering motor reaches the maximum temperature value which can be borne by the steering motor. Scenarios of continuous operation may include, but are not limited to: continuously rotating the steering wheel of the vehicle, blocking the steering motor after the steering wheel is dead, and the like. In order to prolong the continuous working time of the steering motor and avoid the motor from reaching the maximum temperature value too early. The invention provides a steering motor thermal protection control method.

Referring to fig. 1, a flowchart of a steering motor thermal protection control method according to an embodiment of the present invention is shown, where the method includes:

step S10: the method comprises the steps of obtaining a first running duration of the steering motor in a preset maximum working current value state.

In step S10, the steering motor is normally operated at the maximum operating current value. At this time, the steering motor can provide the maximum assist force for steering the vehicle. When the steering motor runs under the state of the maximum working current value, the steering motor can quickly enter thermal protection. Therefore, in the present embodiment, the steering motor is operated at the maximum operating current value for the first period of time. And regulating and controlling the working current value before the first time length is larger than that of the steering motor to achieve thermal protection.

In different vehicle types, different steering motors have different characteristics or matched control components are different; therefore, there may be a difference between the actual maximum operating currents, and the maximum operating current value range of the steering motor in this embodiment may be: 40A to 150A.

Step S20: judging whether the first time length is greater than a preset first assistance time length or not; the first power-assisted duration is the duration when the steering motor reaches a thermal protection temperature value due to the accumulated heat when working at the maximum working current value.

In step S20, the thermal protection temperature value of the steering motor is slightly lower than the maximum temperature value that the steering motor can bear (hereinafter referred to as the maximum temperature value for convenience of description). Specifically, the thermal protection temperature value can be 70% -100% of the maximum temperature value that the steering motor can bear, and can be preferably determined to be 70% -85%; in some embodiments, the thermal protection temperature value can be 80% of the maximum temperature value that the steering motor can bear, which can enable the steering motor to maintain the optimal steering power for a longer time, and can also maintain a longer time for a longer time of larger power after reducing the working current of the steering motor, so that a better balance is obtained between the large torque power and the heat generation of the steering motor. For example, if the maximum temperature value that a steering motor of a certain vehicle type can bear is 125 ℃, the thermal protection temperature value may be determined to be 100 ℃; at this time, the first boosting time is the time required for the steering motor to reach 100 ℃ when working at the maximum working current.

Because the service behavior when same motorcycle type uses all has the difference, for example ambient temperature is different, and the speed of traveling is different, etc.. Therefore, in some embodiments, the first power-assisted duration may be calibrated based on actual experiments of the vehicle type, so as to construct a relation table between the operating condition parameters used by the vehicle and the first power-assisted duration. Before step S20, vehicle operating condition parameters when the steering motor is operating may be obtained; and then, inquiring a relation table according to the vehicle working condition parameters to obtain a first boosting duration. Vehicle operating parameters include, but are not limited to, vehicle speed, ambient temperature of the vehicle, operating current of the steering motor, and the like.

Step S30: when the first time length is longer than the first power-assisted time length, controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work.

In step S30, the first duration is longer than the first boost duration, which indicates that the steering motor has reached the thermal protection temperature value. At this moment, the working current of the steering motor needs to be reduced, the heating of the steering motor is reduced, and the steering motor is prevented from continuously heating to reach the maximum temperature value in a short time, so that the steering motor stops working. After the operating current is reduced, it can be known based on joule's law that the heat accumulation of the steering motor will also slow down, thereby delaying the temperature rise of the steering motor.

In this embodiment, to achieve better effect, the current of the steering motor can be adjusted in two stages. In the first stage, the working current of the steering motor is reduced to an intermediate current value so as to delay the temperature rise of the steering motor while ensuring a better power assisting effect; in the second stage, the working current of the steering motor is continuously reduced to a protective current value, so that the heat dissipation and the heat accumulation are balanced.

Specifically, step S30 may include the following sub-steps:

firstly, controlling the working current value of the steering motor to be reduced to an intermediate current value according to a current coefficient, and monitoring the second time length of the steering motor running in the intermediate current value state; the intermediate current value is greater than the protection current value and less than the maximum working current value. The intermediate current value can be calibrated after the power assisting effect can be evaluated subjectively through experimental tests and by users, so that the time for the steering motor to reach the maximum temperature value can be prolonged as far as possible while the better power assisting effect can be provided. For example, in this embodiment, the intermediate current value may be any value between the protection current value and the maximum working current value, and specifically may take a value of 10A to 40A; but in order to satisfy better power-assisted effect and delay the temperature rise of the steering motor, the intermediate current value can be 20-60% of the maximum working current value; the specific intermediate current value may be 30%, 40%, 50%, 55%, etc. of the maximum operating current value.

Then, judging whether the second time length is greater than a preset second boosting time length or not; the second power-assisted duration is the duration of the heat accumulated when the steering motor works at the intermediate current value and reaches the maximum temperature value which can be borne by the steering motor. Similarly, the vehicle may work under different working conditions, so that the determination of the second power-assisted duration may refer to the first power-assisted duration, or may be calibrated after experimental tests, so as to form a relationship table of the second power-assisted duration. And then, when the power assisting device is used, the second power assisting duration can be determined by looking up a table according to the current working condition environment.

And finally, when the second duration is longer than the preset second boosting duration, controlling the working current value of the steering motor to be reduced to the protection current value according to the current coefficient. And when the second time length reaches the preset second power-assisted time length, the temperature of the steering motor reaches the maximum temperature value. At the moment, the steering motor continues to accumulate temperature, so that the steering motor is ablated, or has heating faults, or is subjected to power-off protection and the like; therefore, when the working current of the steering motor is controlled at the protective current value, the heat generation and the heat dissipation balance can be achieved, so that the temperature of the steering motor is not increased any more, and the power-assisted work of the steering motor can be continuously maintained. Similarly, the protection current value may be calibrated through experiments, and may be different values for different motor types and different working conditions. A corresponding thermal balance data table can be formed after experimental calibration, and the protection current value corresponding to the specific steering motor under the specific working condition environment can be determined through table lookup. For example, the protection current value may be 10A to 40A.

Furthermore, in this embodiment, the magnitude of the current coefficient value is decreased as the operating current of the steering motor decreases, and is increased as the operating current of the steering motor increases. In some implementation modes, the current coefficient value is linearly reduced along with the reduction of the working current of the steering motor, and is linearly increased along with the increase of the working current of the steering motor, so that the stable change of the working current can be realized, the power-assisted effect of the steering motor is ensured to be stable, and sudden change is avoided. That is, in the process of the change of the operating current of the steering motor, the current coefficient also changes dynamically. The relationship between the current coefficient and the operating current can be as shown in fig. 2. In fig. 2, the current value at point a is a protection current value, and the steering motor can achieve balance between heat generation and heat dissipation; maximum Current represents the Maximum operating Current value, and the same shall apply hereinafter.

The current coefficient is linearly reduced along with the reduction of the current, so that the working current can be ensured to be reduced more rapidly (rapid reduction stage) in the case of large current, and the current reduction rate can be gradually reduced (slow reduction stage) after the working current is reduced, so that the steering motor generates less heat in the whole adjustment process, and stronger steering power is provided in the slow reduction stage. The principle of the method can be understood by referring to fig. 3, when the working current of the steering motor is reduced according to the current coefficient shown in fig. 2, the power change curve of the heat generated by the motor is I1; when the working current of the steering motor is linearly reduced, the power change curve of the heating of the motor is I2; at this time, the accumulated heat when the working current is adjusted by using the current coefficient in the present embodiment is S1, and the accumulated heat when the working current is directly linearly adjusted is S1+ S2+ S3; therefore, the accumulated heat of the steering motor may be reduced by S2+ S3, and this part of the reduced accumulated heat may be directed to increase the operating time of the steering motor.

In addition, in the embodiment, after the working condition environment is changed, the protection current value is increased. At this time, the current of the steering motor can be increased, and the current change coefficient when the current is increased is as shown in fig. 3, so that the heat accumulation caused by the too fast motor can be avoided.

In one example, the following set of parameters is provided for implementation: maximum operating current value I_max45A, intermediate current value I_aProtection current value I20A_bWhen the steering motor is out of the thermal protection, the slope K1 of the initial drop of the current is 0.45A/s, and the slope K2 of the rise of the current is 0.1A/s.

With continuing reference to fig. 4, the overall workflow of the steering motor thermal protection control method in the present embodiment is exemplarily illustrated by fig. 4.

Example 1:

when the thermal protection temperature value is the maximum temperature value, when the first time length of the maximum working current value reaches t2, the temperature reaches 125 ℃, the working current can be reduced to the protection current value B1, and the steering motor can reach a thermal balance state. The current curve at this time is C1.

Example 2:

and when the thermal protection temperature value is smaller than the maximum temperature value, setting a value to turn to a platform of the motor working at the intermediate current value. First, when it is monitored that the first period of operation at the maximum operating current value reaches t1, the temperature reaches 100 ℃, and the operating current may be decreased to an intermediate current B2. When the steering motor operates at the intermediate current value B2, the heat accumulation of the steering motor is slow, and the operating time reaching the maximum temperature value can be further increased. Then, when the second time length (T2-T1) reaches the preset second power assisting time length, the temperature reaches 125 ℃, the working current value of the steering motor is controlled to be reduced to the protection current value B1 according to the current coefficient, and the thermal equilibrium state is reached. The current curve at this time is C2.

Compared with the example 1, the adjustment method in the example 2 can further increase the working time of the steering motor in the intermediate current value state, and can provide a better power assisting effect according with the user feeling when the steering motor works in the intermediate current value state. In summary, the adjustment manner in example 2 can provide better boosting effect for the user for a longer time, and the time duration can reach T2, which is much longer than the time duration T2.

In summary, in the steering motor thermal protection control method provided in this embodiment, a first time length of operation of the steering motor in a preset maximum working current value state is obtained; then, judging whether the first time length is greater than a preset first power-assisted time length or not; the first power-assisted duration is the duration of heat accumulated when the steering motor works at the maximum working current value to reach a thermal protection temperature value; when the first time length is longer than the first power-assisted time length, controlling the working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work. The control process can ensure that the working current value of the steering motor can be reduced to protect the working current when the steering motor reaches the thermal protection temperature value, and the protection current value is the current value of the steering motor with balanced heating and heat dissipation, so that the work of the steering motor can be continuously maintained under the protection current value, the steering motor is prevented from being overheated to ablate or stop working due to the fact that the maximum bearing temperature is exceeded, the working stability of the steering motor is ensured, and the service life is prolonged.

Referring to fig. 5, based on the same inventive concept, in another embodiment of the present invention, there is provided a steering motor thermal protection control device 300, where the steering motor thermal protection control device 300 includes:

the detection module 301 is configured to obtain a first time length of operation of the steering motor in a preset maximum working current value state; a determining module 302, configured to determine whether the first duration is greater than a preset first boosting duration; the first power-assisted duration is the duration when the heat accumulated when the steering motor works at the maximum working current value reaches a thermal protection temperature value; the regulation and control module 303 is configured to control a working current value of the steering motor to be reduced to a protection current value according to a preset current coefficient when the first duration is longer than the first boosting duration; the current coefficient is the speed of adjusting the current value, and the protection current value is the current value of the steering motor which is balanced in heating and heat dissipation when in work.

As an optional implementation manner, the regulation module 303 is further specifically configured to:

controlling the working current value of the steering motor to be reduced to an intermediate current value according to the current coefficient, and monitoring a second time length of the steering motor running at the intermediate current value; the intermediate current value is greater than the protection current value; judging whether the second time length is greater than a preset second boosting time length or not; the second power-assisted duration is the duration when the heat accumulated when the steering motor works at the intermediate current value reaches the maximum temperature value which can be borne by the steering motor; and when the second duration is longer than a preset second power-assisted duration, controlling the working current value of the steering motor to be reduced to the protection current value according to the current coefficient.

As an alternative embodiment, the magnitude of the current coefficient value decreases as the operating current of the steering motor decreases.

As an alternative embodiment, the magnitude of the current coefficient value decreases linearly with decreasing operating current of the steering motor.

As an optional implementation manner, the value range of the protection current value is as follows: 10A to 40A.

It should be noted that the implementation and technical effects of the steering motor thermal protection control device 300 provided in the embodiment of the present invention are the same as those of the foregoing method embodiment, and for the sake of brief description, reference may be made to corresponding contents in the foregoing method embodiment for parts of the device embodiment that are not mentioned.

Based on the same inventive concept, a computer-readable storage medium is also provided in yet another embodiment of the present invention, on which a computer program is stored, which when executed by a processor implements the steps of the method described in the aforementioned method embodiment.

It should be noted that, in the computer-readable storage medium provided by the embodiment of the present invention, the specific implementation and the generated technical effect of each step are the same as those of the foregoing method embodiment, and for a brief description, for the sake of brevity, reference may be made to the corresponding contents in the foregoing method embodiment for the non-mentioned part of the present embodiment.

The term "and/or" appearing herein is merely one type of associative relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship; the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.