SE1250655A1 - Diagnosis of boot system - Google Patents

Abstract

A combustion engine (120) in a vehicle is started by means of a start system including an electric starter motor (110). The function of the start system is evaluated by means of a test system comprising measuring elements, a starter motor analyzer (160) and a control unit (170). The measuring elements measure a supply voltage to the electric starter motor (110) and an rpm of the combustion engine ( 120) when the starter motor (110) is activated. The starter motor analyzer (160) defines, based on the supply voltage and the rpm, a preliminary status (S) of the start system. Based on the preliminary status (S), the control unit (170) evaluates whether information in addition to the supply voltage and the rpm is needed. If such is the case, an interactive communication process is executed wherein an operator (OP) is called upon to input information (OPInp) to the control unit (170) in at least one process step. An expanded status message (TR) that defines a functional status for the start system is generated by the control unit (170) on the basis of the interactive communication process.

Description

A signal to an operator is generated (such as lighting a warning lamp) if at least one charging voltage is outside a predetermined range. The operator of the system may also be asked to take one or more actions in response to the generated signal.

PROBLEMS RELATED TO PRIOR ART There are thus various solutions for examining the function of a starting system in a motor vehicle. However, there is no example of a solution which, on the one hand, allows a simple diagnosis during normal operation of a vehicle, and on the other hand ensures that all adequate parameters are taken into account in the diagnosis.

SUMMARY OF THE INVENTION The object of the present invention is therefore to provide a solution to this problem and which thus enables a simple, safe and reliable diagnosis of the starting system of a motor vehicle.

According to one aspect of the invention, the object is achieved by the test system initially described, the test system comprising a control unit configured to activate the start-up system only in response to a start-up request from an operator. This ensures that a potentially dangerous measure such as starting the vehicle's engine can not take place in any other way than via the operator's initiative. The control unit is also configured to perform the following steps based on the preliminary status: examine whether information in addition to supply voltage and speed is required for the current diagnosis; and if so, execute an interactive communication procedure. This procedure involves an operator being prompted to enter information into the controller in at least one procedural step. Based on the interactive communication procedure, the controller is configured to generate an extended status message, which describes a functional status of the boot system. This system is advantageous because the tests can thereby be very flexible and be based on data concerning the vehicle which are very complicated to obtain automatically, such as observing clicking sounds from the electric starter motor. The interactive communication procedure is generally advantageous as it enables an efficient division of measures between operator and machine, such as with regard to measurement and calculation. This in turn guarantees both the robustness and accuracy of the system.

According to an embodiment of this aspect of the invention, the test system comprises at least one user interface, which is configured to present to the operator information generated by the control unit; and receive input signals from the operator. Thus, an efficient exchange of information can be effected.

According to another embodiment of this aspect of the invention, the control unit is configured to receive at least one sensor signal in addition to the basic technical data in the form of supply voltage to the electric starter motor and a speed of the internal combustion engine. The control unit is configured to generate the extended status message on a wider basis of the at least one sensor signal. Thus, for example, the tests can further be based on one or more voltage measurements in critical parts of the starting system.

According to yet another embodiment of this aspect of the invention, the control unit is configured to examine, via an interactive communication procedure with an operator, whether basic conditions exist for allowing activation of the starter motor. Only if the mentioned basic conditions are present is the control unit configured to enable activation of the starter motor. The basic preconditions may, for example, include fulfillment of a starting condition regarding an alcohol lock in the vehicle and / or that the internal combustion engine is not in operation. Thus, important security risks can be avoided.

According to another embodiment of this aspect of the invention, the at least one user interface is configured to receive input signals from the operator concerning at least one of the acoustic and optical signals generated by the vehicle in connection with activation of the starter motor, such as any noises from the engine. This type of data is normally very difficult to obtain automatically from the vehicle.

According to yet another embodiment of this aspect of the invention, the test system comprises one or more temperature measuring means configured to measure at least one temperature related to the vehicle. The starter motor analyzer is configured here to determine the preliminary status on a wider basis of the at least one measured temperature. For example, the ambient temperature and a characteristic temperature of the internal combustion engine are important parameters when assessing the function of the electric starter motor.

According to embodiments of this aspect of the invention, the object is achieved by the method initially described, wherein the start-up system is activated only in response to a start-up request from an operator. On the basis of the preliminary status, the following steps are also performed: examination of data in addition to the said technical basic data is required; and if so, executing an interactive communication procedure in which the operator is prompted to enter information into the control unit in at least one procedural step, and based on the interactive communication procedure; generating an extended status message, which describes a functional status of the boot system. The advantages of this method, as well as of the preferred embodiments thereof, are apparent from the discussion above with reference to the proposed system.

According to a further aspect of the invention, the object is achieved through a computer program directly downloadable to the internal memory of a computer, comprising software for controlling the steps according to the method proposed above when said program is run on a computer. According to yet another aspect of the invention, the object is achieved by a computer-readable medium having a program stored thereon, the program being adapted to cause a computer to control the steps according to the method proposed above.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be explained in more detail by means of embodiments, which are described by way of example, and with reference to the accompanying drawings.

Figure 1 shows a schematic view of a proposed system, Figure 2 shows an overview of how an electric starter motor according to an embodiment of the invention can be arranged to start an internal combustion engine in a motor vehicle, Figure 3a-b shows graphs which illustrates how a preliminary status of a starting system can be determined according to embodiments of the invention, and shows a flow chart which illustrates the general method according to the invention.

FIGURE 4 DESCRIPTION OF EMBODIMENTS OF THE INVENTION We first refer to Figure 1, which shows a schematic view of a proposed test system for examining the operation of a starting system in a motor vehicle. Starting systems are assumed to be arranged to start an internal combustion engine 120 in the vehicle via an electric starter motor 110.

The test system comprises: measuring means, a starter analyzer 160 and a control unit 170. Figure 2 shows in some detail how the electric starter 110 according to an embodiment of the invention is connected to the internal combustion engine 120. Figure 2 also shows the above-mentioned measuring means 130 and 140, which are configured to measure basic technical data including a supply voltage to the electric starter 110 and an RPM 10 of the internal combustion engine 120 when the starter 110 is activated.

The starter motor analyzer 160 is configured to determine a preliminary status S for the starter system based on the said basic technical data U and RPM.

The control unit 170 is configured to activate the start-up system only in response to a start-up request from an OP operator. This is important because it ensures that neither the electric starter 110 nor the internal combustion engine 120 can be started other than on the initiative of the OP operator, for example by turning a starter key. Thus, situations that are potentially dangerous for service personnel and that arise as a result of the vehicle being started at an unexpected time for this personnel can be avoided.

The control unit 170 is also configured to, on the basis of the preliminary status S, examine whether information is required in addition to the said technical basic data U and RPM in order to be able to determine an extended status message describing the functional status of the start-up system. If such additional information is required, the controller 170 is configured to execute an interactive communication procedure. This procedure in turn involves the operator OP being prompted to input information OP1np to the controller 170 in at least one procedural step, preferably via a user interface 180. Based on the interactive communication procedure, the controller 170 is configured to generate an extended status message TR. which describes a functional status for the start-up system.

The user interface 180 is advantageously configured to present to the operator OP information DReq generated by the control unit 170, and TR via a screen and / or acoustic messages.

Furthermore, the user interface 180 suitably comprises at least one means configured to receive input signals OP1np from the operator OP, typically in the form of answers to questions Dreq from the controller 170 asked to the operator OP via a user interface 10 15 20 25 30 180. The user interface can thus include a keyboard and / or voice command recording device. The user interface 180 can thus be used, for example, to receive input signals OP1np from the operator OP concerning acoustic and / or optical signals generated by the vehicle in connection with activation of the starter motor 110.

According to one embodiment of the invention, the control unit 170 is configured to receive at least one sensor signal [si] in addition to the basic technical data in the form of supply voltage U to the electric starter motor and the RPM speed of the internal combustion engine. The sensor signals [si] can, for example, represent voltage levels at critical points in the starting system. The control unit 170 is configured to generate the extended status message TR on a further basis of the at least one sensor signal [si]. If the said technical basic data U and RPM, for example, due to an anomaly provide an insufficient or unreliable basis, the sensor signals can [si] supplementary data for diagnosing the starting system.

When a characteristic temperature of the internal combustion engine 120 affects the conditions of the electric starter 110 to start the internal combustion engine 120, the test system according to an embodiment of the invention comprises one or more temperature measuring means configured to measure at least one temperature related to the vehicle. The starter motor analyzer 160 is configured here to determine the preliminary status S on a further basis of the at least one measured temperature.

The control unit 170 is advantageously also configured to check via an interactive communication procedure with an operator OP whether basic conditions exist to allow activation of the starter motor 110. Only if such basic conditions exist is the control unit 170 configured to enable activation of the starter motor 110. Examples of basic conditions of this kind are the fulfillment of a starting condition regarding an alcohol lock in the vehicle and that the internal combustion engine 120 is not already in operation. By examining whether the basic conditions are met, safety risks for both people and equipment can be avoided.

We now return to Figure 2, which shows an overview of a system according to the invention for diagnosing an electric starter 110. The electric starter 110 is assumed to be part of a vehicle equipped with an internal combustion engine 120, where the electric starter 110 is configured to start the internal combustion engine 120. The electric starter motor 110 is in turn energized with the advantage of a battery 135.

The proposed system comprises measuring means 130 and 140, respectively, and a starter motor analyzer 160. In addition, temperature measuring means (not shown) are advantageously included.

The measuring means 130 and 140 are configured to measure technical quantities related to the vehicle. The technical quantities represent a supply voltage U to the starter motor 110 and one RPM of the internal combustion engine 120, respectively. In the following description, the RPM speed of the internal combustion engine 120 is discussed throughout. When the starter motor 110 and the internal combustion engine 120 are connected (e.g. via a so-called Bendix coupling) there is of course a relationship between the speed of the internal combustion engine 120 and the speed of the starter motor 110, why a measured speed of the starter motor 110 can be used as well as the proposed RPM speed of the internal combustion engine 120. said temperature measuring means is configured to measure temperature T related to the vehicle. The at least one temperature T can for instance refer to an ambient temperature at the vehicle, an oil temperature in the engine, a cooling water temperature, an engine block temperature, a starter engine temperature and / or a battery temperature. It is advantageous to record more than one temperature, as this allows an assessment of whether the vehicle is cold started (all temperatures are substantially the same), warm started (the oil temperature in the engine and a cooling water temperature significantly exceeds the ambient temperature), or is started in a semi-hot state (the cooling water temperature significantly exceeds the ambient temperature, but the oil temperature in the engine is relatively low).

The starter motor analyzer 160 is configured to, based on the measured technical quantities U and RPM and the temperature T, determine a preliminary status S for the starter 110, which preliminary status S indicates a quality measure of the performance of the starter 110.

For increased reliability / robustness, the measuring means 130 and 140, according to an embodiment of the invention, are configured to measure the technical quantities during a measuring interval, say 1 second during which measuring interval, for example, 10 individual measurements are registered.

Alternatively, the measurement range may be adaptively coupled to one or more compression cycles of the internal combustion engine 120, so that the measurement range represents an integer number of compression cycles.

A typical compression cycle is about 15 ms long. As an alternative to a pure averaging of the RPM speed, the starter motor analyzer 160 may in such a case be configured to record a minimum speed during a compression cycle. Start-up performance has in fact been shown to depend on speed when it is at its lowest. Further, the starter analyzer 160 may be configured to average between a respective lowest measured supply voltage U to the starter 110 in each of a number of compression cycles.

The starter analyzer 160 can thus be configured to average the measured technical quantities over the measuring range and determine the preliminary status S on the basis of an average value of the supply voltage Uavg to the starter 110 during the measuring range and an average of the RPMaVg speed of the internal combustion engine 120. Correspondingly, the temperature measuring means is suitably configured to measure at least one temperature T during a measuring interval. If so, of course, the starter motor analyzer 160 is configured to average the at least one measured temperature T over the measurement range, and utilize at least one of the at least one averaged temperature in determining the preliminary status S.

It may also be advantageous to adapt the diagnostic method performed by the starter motor analyzer 160 depending on seasonal changes. For example, a temperature adjustment can be made in two steps (summer / winter), in several steps (such as below -25 ° C, between -25 ° C and -20 ° C, between -20 ° C and -10 ° C, between -10 ° C and i0 ° C, between i0 ° C and 10 ° C, and above 10 ° C), or continuously on the basis of a defined ratio, for example: RPMeXp = U> <P1 / (T + P2), where RPMeXp indicates the expected speed, U indicates the measured supply voltage to the starter motor 110, T indicates a measured temperature and P1 and P2 are adaptation parameters.

Figure 3a shows a first graph illustrating how the preliminary status S is assigned according to an embodiment of the invention. The graph shows an average supply voltage Uavg to the starter motor 110 along the horizontal axis and an average RPMaVg of the internal combustion engine 120 along the vertical axis.

According to this embodiment of the invention, the starter motor analyzer 160 is configured to, for example, categorize the preliminary status S as OK if the function of the starter 110 is considered acceptable, and categorize the preliminary status S as NOT if the starter 110 is not considered to operate satisfactorily.

The preliminary status S is categorized as OK if the measured supply voltage Uavg exceeds a voltage threshold Um and the measured speed simultaneously exceeds a speed threshold RPMth.

It is advantageous to calculate the preliminary status S continuously by comparing a measured RPM with an expected speed and applying at least one threshold level (for example a first level representing an acceptable starter motor function OK and a second level corresponding to a unacceptable starter motor function NOT) for example according to the ratio below: O _ RPM + N1 (T) u / N2 (T) where RPM indicates a measured speed in a start attempt, T indicates a measured temperature (such as a characteristic motor temperature), U indicates a measured supply voltage at the start test, N1 (T) indicates a speed offset at temperature T, and N2 (T) indicates a speed parameter at temperature T.

Under the above conditions, the preliminary status will be S = 80 if the starter motor function is good. S 2 70 can thus correspond to an acceptable starter motor function OK. If, on the other hand, S <70, the starter motor function is considered unacceptable NOT, so a replacement of the starter motor should be recommended.

In addition, it is advantageous if the starter motor analyzer 160 applies an adaptive side condition which is dependent on the at least one measured temperature T. This may mean that, at a first temperature T1, the speed must exceed the speed threshold RPMth in relation to how much the supply voltage Uavg exceeds one first control voltage Um, where Um 2 Um. The adaptive side condition is advantageously inversely proportional to the at least one measured temperature T.

To illustrate this, we refer to Figure 3b, where a second graph shows how the starter motor analyzer 160 assigns the preliminary status S. 1 similar to Figure 3a. the graph here shows an average supply voltage Uavg to the starter motor 110 along the horizontal axis and an average RPMaVg of the internal combustion engine 120 along the vertical axis.

In Figure 3b, a measured temperature T is assumed to have a value T2> T1. 10 15 20 25 30 12 The fact that the adaptive auxiliary condition is inversely proportional to the measured temperature T means that, at a higher temperature T, for a given supply voltage Uavg, a higher speed RPMaVg is required for the function of the starter motor 110 to be considered acceptable ( and the preliminary status S shall be assigned the first value OK). The temperature-dependent secondary condition according to the graph in Figure 3b therefore has a steeper slope than in Figure 3a.

In order to further tighten the speed requirement at an increased temperature T, a second control voltage Um, at a higher temperature T2> T1, can also be given a lower value, i.e. Um <Um, where the Ubrz 2 Uth starter motor analyzer 160 is thus advantageously configured to apply the adaptive auxiliary condition on the basis of the measured temperature T so that, at a relatively high measured temperature T2, a relatively low measured supply voltage Uavg must correspond to a measured speed exceeding the RPMth speed threshold for the adaptive auxiliary condition to be considered fulfilled and the preliminary status S is assigned the first value OK.

At a relatively low measured temperature T1, on the other hand, the starter motor analyzer 160 is advantageously configured to assign the preliminary status S, so that a relatively high measured supply voltage Uavg can correspond to a measured speed just above the speed threshold RPMm, the adaptive additional condition being considered and the preliminary status S is assigned the first value OK.

If the measured supply voltage Uavg is below the voltage threshold Um, it is, as mentioned above, impossible to determine the function of the starter motor. According to an embodiment of the invention, therefore, the starter motor analyzer 160 in such a case is configured to assign the preliminary status S a third value UNDEF representing that the function of the starter motor cannot be determined. The starter motor analyzer 160 is suitably controlled to operate according to 10 15 20 25 30 13 above by means of a computer program stored in a memory unit 165, which is included in the starter motor analyzer 160 or is communicatively connected thereto.

In order to summarize, the general method according to the invention will now be described together with a preferred embodiment thereof with reference to the flow chart in Figure 4.

In a first step 405, it is examined whether a basic precondition for activating the starter motor and thereby being able to test it exists. Examples of such basic conditions may be that a starting condition regarding an alcohol lock in the vehicle must be met and that the internal combustion engine must not be in operation. If the applicable prerequisites are met, a step 410 follows, otherwise the procedure proceeds directly to a step 455. In this step, a status message is generated, indicating that at least one condition for being able to test the boot system is not met. Appropriately, an operator of the vehicle is also informed of appropriate measures to meet the necessary conditions.

Step 410 executes an interactive communication procedure in which the operator is prompted to enter information in at least one procedural step. This can be anything from a very simple confirmation that no gear is engaged to entering a long sequence of answers, where a certain question is conditioned by the answer to a previous question concerning, for example, settings and configurations of it. the vehicle. A subsequent step 415 (which may advantageously be iteratively inserted between each individual question in step 410) examines whether the required information has been obtained from the operator. If so, a step 420 follows, otherwise the procedure loops back to step 410.

Step 420 examines whether the electric starter motor, in response to an operator request, has been activated. If so, steps 425 and 430 follow; and if not, the procedure loops back and stops in step 420.

In step 425 a speed of the internal combustion engine is recorded and in step 430 (which is preferably performed in parallel with step 425) a supply voltage to the electric starter motor is recorded. On the basis of this basic technical data, a preliminary status of the start-up system is determined in a step 435. Next, a step 440 examines whether additional information is required to determine the functional status of the boot system. If in step 440 it is judged that no further information is needed, without the said technical basic data having provided an adequate basis, then the procedure proceeds to step 455. In step 455 a status message concerning the functional status of the start-up system is generated exclusively. on the basis of the above-mentioned supply voltage and speed.

For example, if either of the registrations in steps 425 and 430, respectively, fails (or results in values that deviate significantly from what are normal values for a functioning boot system), then the preliminary status determined in step 435 will provide incomplete and / or misleading information about the starting system.

Therefore, step 440 will require additional information, which in turn results in the procedure instead proceeding to a step 445. In analogy to step 410 above, an interactive communication procedure is executed in step 445 in which the operator is prompted to enter information in at least one procedure step. Here, too, the interactive procedure can involve everything from entering a simple confirmation to going through long question-and-answer sequences.

For example, the operator may be prompted to listen for different types of sounds from the boot system in response to various actions, and enter information about them.

A subsequent step 450 (which may advantageously be iteratively inserted between each individual question in step 445) examines whether the required information has been obtained from the operator. If this is the case, step 455 follows, otherwise the procedure loops back to step 445. In step 455, in this case, a status message is generated concerning the functional status of the start-up system on the basis of both the said technical basic data and the information obtained via step 445. Then the procedure ends. The method steps described with reference to Figure 4 can be controlled by means of a programmed computer apparatus. In addition, although the embodiments of the invention described above with reference to the figures include a computer and processes performed in a computer, the invention extends to computer programs, especially computer programs on or in a carrier adapted to practically implement the invention. The program may be in the form of source code, object code, a code which is an intermediate between source and object code, such as in partially compiled form, or in any other form suitable for use in implementing the process according to the invention. The carrier can be any entity or device which is capable of carrying the program. For example, the carrier may comprise a storage medium such as a flash memory, a Read Only Memory (ROM), for example a CD (Compact Disc) or a semiconductor ROM, EPROM (Electrically Programmable ROM), EEPROM (Erasable EPROM ), or a magnetic recording medium, such as a floppy disk or hard disk. In addition, the carrier may be a transmitting carrier such as an electrical or optical signal, which may be conducted by an electrical or optical cable or by radio or other means. When the program is formed by a signal which can be conducted directly by a cable or other device or means, the carrier can be constituted by such a cable, device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, where the integrated circuit is adapted to perform, or to be used in performing, the actual processes.

The invention is not limited to the embodiments described with reference to the figures but can be varied freely within the scope of the appended claims.

Claims (18)

10 15 20 25 30 16 Patent claims A test system for examining the function of a starting system in a vehicle, which starting system is arranged to start an internal combustion engine (120) in the vehicle via an electric starting motor (110), the test system comprising: measuring means (130, 140 ) configured to measure basic technical data including a supply voltage (U) to the electric starter motor (110) and a speed (RPM) of the internal combustion engine (120) when the starter motor (110) is activated, and a starter analyzer (160) configured to based on said technical basic data (U, RPM) determine a preliminary status (S) of the starting system, characterized in that the test system comprises a control unit (170) configured to activate the starting system only in response to a start request from an operator (OP), and based on the preliminary status (8): examine whether data in addition to the said technical basic data (U, RPM) are required, and if so, execute an interactive communication procedure in which the operator (OP) is requested to: input information (OPlnp) to the control unit (170) in at least one procedure step, and based on the interactive communication procedure generate an extended status message (TR) describing a functional status of the boot system. The test system of claim 1, comprising at least one user interface (180) configured to present to the operator (OP) the control unit (170) generated information (DReq, TR), and receive input signals (OP1np) from the operator (OP) . The test system according to any one of claims 1 or 2, wherein the control unit (170) is configured to receive at least one sensor signal ([s,]) in addition to said technical basic data (U, RPM) and generate the extended status message (TR) on a wider basis of the at least one sensor signal ([s,]). 10 15 20 25 30 17 The test system of any preceding claim, wherein the control unit (170) is configured to: examine, via an interactive communication procedure with an operator (OP), whether basic conditions exist to allow activation of the electric starter motor (110); and only if said basic conditions exist enable activation of the electric starter motor (110). The test system according to claim 4, wherein said basic conditions comprise fulfillment of a starting condition regarding an alcohol lock in the vehicle. The test system of any of claims 4 or 5, wherein said basic conditions comprise that the internal combustion engine (120) is not in operation. The test system of any of claims 2 to 6, wherein the at least one user interface (180) is configured to receive input signals (OP1np) from the operator (OP) relating to at least one of the acoustic and optical signals generated by the vehicle in in connection with activation of the electric starter motor (110). The test system of any preceding claim: comprising at least one temperature measuring means configured to measure at least one temperature related to the vehicle, and the starter motor analyzer (160) is configured to determine the preliminary status (S) on a further basis of the at least one measured the temperature. A method for examining the operation of a starting system in a vehicle, the starting system being arranged to start an internal combustion engine (120) in the vehicle via an electric starting motor (110), the method comprising: measuring technical basic data including a food 10 Voltage (U) to the electric starter (110) and a speed (RPM) of the internal combustion engine (120) when the electric starter (110) is activated, and determining a preliminary status (S) of the starter system based on said technical basic data (U, RPM), characterized by activation of the starting system only in response to a start request from an operator (OP), and based on the preliminary status (S): examination of data in addition to said technical basic data (U, RPM ) is required, and if so, the execution of an interactive communication procedure in which an operator (OP) is prompted to input information (OPlnp) to the control unit (170) in at least one procedural step, and based on the interactive The iva communication procedure generates an extended status message (TR) which describes a functional status of the boot system. The method of claim 9, comprising: presenting generated information (DReq, TR) to an operator (OP), and receiving input signals (OP1np) from the operator (OP). The method of any of claims 9 or 10, comprising: receiving at least one sensor signal ([s,]) in addition to said technical basic data (U, RPM), and generating the extended status message (TR) on a further basis of the at least one the sensor signal ([s,]). The method according to any one of claims 9 to 11, comprising: examining, via an interactive communication procedure with an operator (OP), whether basic conditions exist to allow activation of the electric starter motor (110), and only if said basic conditions exist enabling of activating the electric starter motor (110). 10 15 20 19 The method of claim 12, wherein said prerequisites comprise meeting a starting condition regarding an alcohol interlock in the vehicle. The method of any of claims 12 or 13, wherein said basic conditions comprise that the internal combustion engine (120) is not in operation. The method according to any one of claims 10 to 14, comprising receiving input signals (OP1np) from the operator (OP) concerning at least either of acoustic and optical signals generated by the vehicle in connection with activation of the electric starter motor (110). The method according to any one of claims 9 to 15, comprising: measuring at least one temperature related to the vehicle, and determining the preliminary status (S) on a further basis of the at least one measured temperature. A computer program directly downloadable to the internal memory (165) of a computer, comprising software for controlling the steps of any of claims 9 to 16 when said program is run on the computer. A computer readable medium (165) having a program stored thereon, wherein the program is adapted to cause a computer to control the steps of any of claims 9 to 16.