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Title:
CONTROL MODULE FOR ADJUSTING FLAPS OF A VEHICLE
Document Type and Number:
WIPO Patent Application WO/2019/147125
Kind Code:
A1
Abstract:
A control unit is presented for controlling a driving unit arranged for adjustment of one or more first air guiding flaps of a motorised vehicle between a first outer position and a second outer position. The control unit comprises a communication module for communicating with a vehicle control network for receiving first adjustment instructions for adjusting the first flap, a power supply module comprising an input power terminal for receiving power from a vehicle power network and a first output power terminal for supplying a first current to the driving unit. The control unit further comprises a current sensor module for sensing variations in the first supply current and a control module arranged to control the first supply current in accordance with the adjustment instructions and the sensed variations. By separating the control module from the driving unit, functionality of the control module may be shared over multiple driving units.

Inventors:
BRAND, Marius (3447 GK Woerden, NL)
HUIJZERS, Bastiaan (3447 GK Woerden, NL)
HU, Jinku (3447 GK Woerden, NL)
Application Number:
NL2018/050511
Publication Date:
August 01, 2019
Filing Date:
July 23, 2018
Export Citation:
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Assignee:
MCI (MIRROR CONTROLS INTERNATIONAL) NETHERLANDS B.V. (Pompmolenlaan 29, 3447 GK Woerden, NL)
International Classes:
B60K11/08; H02P7/00
Foreign References:
US20140288760A12014-09-25
US20130043820A12013-02-21
DE202013002675U12013-04-26
US20140039765A12014-02-06
NL2009105C22014-01-06
Attorney, Agent or Firm:
JANSEN, C.M. (V.O, Carnegieplein 5, 2517 KJ Den Haag, NL)
Download PDF:
Claims:
Claims

1. Control unit for controlling a first driving unit arranged for

adjustment of one or more first air guiding flaps of a motorised vehicle between a first outer position and a second outer position, the control unit comprising:

- A communication module for communicating with a vehicle

control network for receiving first adjustment instructions for adjusting the first flap;

A power supply module comprising an input power terminal for receiving power from a vehicle power network and a first output power terminal for supplying a first current to the first driving unit;

A current sensor module for sensing variations in the first supply current; and

A control module arranged to control the first supply current in accordance with the adjustment instructions and the sensed variations.

2. Control unit according to claim 1, wherein the control module is arranged to determine an amount of change in a position of the first driving unit by counting a number of sensed variations in the supply current.

3. Control unit according to claim 1 or 2, wherein the control module is arranged to determine a speed of the first driving unit based on a time interval between at least two variations.

4. Control unit according to claim 3, wherein the control module is arranged to determine the first flap is in either the first outer position or the second outer position upon detecting a change in a frequency of variations or a time period between at least two variations.

5. Control unit according to claim 4, wherein the control module is arranged to determine the first flap is in either the first outer position or the second outer position upon not detecting variation in the supply current for a pre-determined amount of time.

6. Control unit according to any of the preceding claims, wherein the control module is arranged to:

Obtain a first position of the first flap;

Determine, based on the first adjustment instructions, a second position of the first flap;

Determine, based on the first position of the flap and the second position of the flap, a signage of the first supply current to be applied and an amount of variations to occur in the first supply current for the first driving unit to move the flap from the first position to the second position;

Apply the first supply current;

Count an amount of variations in the first supply current;

Switch off the first supply current if the counted amount is substantially equal to the determined amount.

7. Control unit according to any of the preceding claims, wherein:

The power supply module comprises a second power output terminal arranged to supply power to a second driving unit;

The current sensor module is further arranged to sense variations in a second supply current provided to the second driving unit; The control unit is further arranged to control the second supply current in response to the adjustment instructions and the sensed variations.

8. Control unit according to claim 7, wherein:

The communication unit is arranged to receive at least one data message from the vehicle control network and extract, from the received data message or received data messages, the first adjustment instructions and second instructions;

The control module is arranged to provide the first driving unit with the first supply current in accordance with the first adjustment instructions and to provide the second driving unit with a second supply current in accordance with the second adjustment instructions.

9. Control unit according to claim 8, wherein the communication unit is:

Addressable over the vehicle control network by means of a first address and a second address; and

Arranged to receive, from the vehicle control network, a first message addressed at the first address comprising first adjustment instructions and a second message addressed at the second address comprising second adjustment instructions.

10. Control unit according to claim 8, wherein at least one data

message is a single data message addressed over the vehicle control network at the control unit, the data message comprising at least one of a first sub-message comprising a first sub-address of the first driving unit and the first adjustment instructions and a second sub-message comprising a second sub-address of the second driving unit and the second adjustment instructions.

11. Control unit according to claim 7, wherein the control unit is arranged to:

Cause the power supply module to provide substantially the same supply current to the first driving module and the second driving module;

Count a first amount of variations in the first supply current and a second amount of variations in the second supply current;

Determine a malfunction of the first driving module if the first amount of variations differs more than a pre-determined amount from the second amount.

12. Control unit according to claim 11 wherein the control unit is further arranged to:

compare the first amount of variations to the second amount of variations;

perform at least one of: increasing the first supply current; or decreasing the second supply current, if the first amount is less than the second amount by more than the pre-determined amount; and

perform at least one of: increasing the second supply current; or decreasing the first supply current, if the first amount is more than the second amount by more than the pre-determined amount.

13. Control unit according to 7, 11 or 12, wherein:

The communication unit is arranged to receive at least one data message from the vehicle control network and extract, from the received data message or received data messages the first adjustment instructions;

The control module is arranged to provide the first driving unit and the second driving unit with the first supply current in accordance with the first adjustment instructions.

14. Control unit according to claim 7, 8, 11, 12 or 13, wherein the control unit is arranged to provide substantially the same current level to the first driving unit and to the second driving unit.

15. Control unit according to any of the preceding claims, wherein the first power output terminal comprises one or two conductive contact points for supplying the first supply current to the first driving unit.

16. Control unit according to any of the preceding claims, wherein the communication module is arranged to communicate with the vehicle control network via a bus system. 17. Control unit according to any of the preceding claims, wherein the flaps are shutters of an engine compartment of the motorised vehicle.

18. Driving system for adjustment of one or more first air guiding flaps of a motorised vehicle, comprising the control unit of any of the preceding claims and the first driving unit for adjusting the first flap.

19. Driving system according to claim 18, wherein the control unit and the first driving unit are provided in separate housings and connected through two conductive wires. 20. Driving system according to claim 18 or claim 19, wherein the control unit and the first driving unit are provided in a single housing.

21. Motorised vehicle comprising the driving system according to any of the claims 18 to 20, further comprising an air guiding flap actuable by the first driving unit.

22. Motorised vehicle according to claim 21 to the extent dependent on claim 7, wherein the driving system comprises the second driving unit and the air guiding flap is actuable by the first driving unit and the second driving unit.

Description:
Title: control module for adjusting flaps of a vehicle

TECHNICAL FIELD

The various aspects and embodiments thereof relate to the field of control modules for controlling actuators for adjusting positions of air guiding flaps in motorised vehicles.

BACKGROUND

Motorised vehicles like cars and lorries comprise a significant amount of parts of which the positions may be adjusted by means of electrically driven actuators. Such parts may be shutters of an active grill shutter system, AGS, an air dam and/or one or more spoilers. The actuators are preferably driven by means of an in-vehicle network system. An example of such system is the LIN (Local Interconnect Network) protocol. An issue with the LIN protocol, but also with other protocols for bus systems for in- vehicle networking is that only a limited amount of actuators may be coupled to and addressed by a central vehicle control unit.

SUMMARY

It is preferred to provide a controller addressing at least one deficiency referenced above. Furthermore, it is preferred to be able to dispose of less expensive actuators than directly addressable actuators.

A first aspect provides a control unit for controlling a first driving unit arranged for adjustment of one or more first air guiding flaps of a motorised vehicle between a first outer position and a second outer position. The control unit comprises a communication module for communicating with a vehicle control network for receiving first adjustment instructions for adjusting the first flap, a power supply module comprising an input power terminal for receiving power from a vehicle power network and a first output power terminal for supplying a first current to the first driving unit. The control unit further comprises a current sensor module for sensing variations in the first supply current and a control module arranged to control the first supply current in accordance with the adjustment

instructions and the sensed variations. The current may be measured directly or indirectly. In the latter case, variations in a supply voltage may be measured or otherwise detected.

By separating the control module from the driving unit, functionality of the control module may be shared over multiple driving units. This allows for driving units that cost less than driving units with full control functionality built in. Furthermore, the communication module may be addressed by means of a single address with a message that comprises instructions for one of more driving units. Hence, the control module may also act as a de-multiplexer, for example by sharing one external address with multiple internal addresses, for example one for each driving unit.

By providing the current sensor module as described above, a position may be derived from sensing the current and monitoring variations in the supply current. The latter point makes further feedback

communication superfluous or at least reduces the need for detection elements for providing feedback on positions. Currently available actuators comprise position sensors like annular encoders like potentiometers and are relatively expensive and more than two conductors - wires - are required for feedback. The control unit according to the first aspect requires only two - or in certain cases only one - conductive wires for a connection with a driving- unit and no position sensor in the driving unit itself. This results in reduction of a bill of materials.

Dutch patent NL2009105 only partially resolves the issues, as each driving unit disclosed in this publication requires a position sensor, multiple types of driving units are required (master and slave) and the amount of wires is still relatively high. In an embodiment, the control module is arranged to determine an amount of change in a position of the first driving unit by counting a number of sensed variations in the supply current. Every detected variation may be counted. Alternatively, a multiple of variations may be counted, for example two or three or an amount corresponding to a number of brushes or a number of a DC electromotor.

Electromotors and brushed DC electromotors as commonly used in actuators in the automotive industry, preferably have an uneven amount of commutators for supplying current to coils on their rotors. Each switch of powering of the coils results in a variation of the supply current. Per revolution of the rotor, variations occur in the supply current with an amount that is twice the amount of coils.

In an embodiment, the control module is arranged to determine the first flap is in either the first outer position or the second outer position upon detecting an change in a frequency of variations or a time period between at least two variations.

A simple case on this is when a flap is blocked in its outer position. With the flap rigidly connected to the rotor of the electromotor or rigidly connected to a shaft that is driven by the electromotor via a drivetrain comprising gears, the electromotor will stall if the flap cannot be moved anymore. Stalling of the electromotor will result in a stop of switching supply of the coils in the rotors and hence, a stop in variations in the supply current. Otherwise, the flap is connected to the driving unit by means of a shpping connection. In such case, the electromotor will revolve with less revolutions if the flap is in an outer position in which it stalls or enter in a shp -stall alternating situation, as the slip torque must be higher than the running torque, so the motor speed will be reduced. In both cases, the number of variations in the supply current, the frequency of the variations, will change compared to normal operation. In another embodiment, the control module is arranged to obtain a first position of the first flap, determine, based on the first adjustment instructions, a second position of the first flap and determine, based on the first position of the flap and the second position of the flap, a signage of the first supply current to be applied and an amount of variations to occur in the first supply current for the first driving unit to move the flap from the first position to the second position. Subsequently, the first supply current is applied, the amount of variations in the first supply current is counted and the first supply current is switched off if the counted amount is

substantially equal to the determined amount.

As the number of variations is more or less linearly coupled to an amount of revolutions of a shaft of an electromotor driving the flap of which the supply current is sensed, a position of the flap may be deduced from a starting position, a sign of the current - positive or negative - and an amount of variations sensed.

In a further embodiment, the power supply module comprises a second power output terminal arranged to supply power to a second driving unit, the current sensor module is further arranged to sense variations in a second supply current provided to the second driving unit, and the control unit is further arranged to control the second supply current in response to the adjustment instructions and the sensed variations.

In such embodiment, intelligence is provided in the control unit. This allows relatively simple actuators to be used as driving units.

Furthermore, as discussed above, such control unit acts as a demultiplexer.

In again another embodiment, the control unit is arranged to cause the power supply module to provide substantially the same supply current to the first driving module and the second driving module. The control unit is further arranged to count a first amount of variations in the first supply current and a second amount of variations in the second supply current. A malfunction of the first driving module is determined if the first amount of variations differs more than a pre-determined amount from the second amount. Optionally, operation of more than two actuators may be monitored in this way.

With substantially the same driving units provided with substantially the same current, substantially the same amount of variations are expected to be counted in both supply currents. If this is not the case, there is a malfunction in either one of the driving units.

In yet a further embodiment, the first power output terminal comprises one or two conductive contact points for supplying the first supply current to the first driving unit. As driving of the driving units is controlled in response to data measured in the supply current, no further electronics and no further communication between the control unit and the driving unit(s) is required. Hence, two and in some cases only one conductive wire is required between the control unit and the driving unit. In the latter case, one conductive wire is replaced by, for example, the frame of the vehicle.

A second aspect provides a driving system for adjustment of one or more first air guiding flaps of a motorised vehicle, comprising the control unit of the first aspect and a driving unit for adjusting the first flap.

A third aspect provides a motorised vehicle comprising the driving system according to the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects and embodiments thereof will now be discussed in conjunction with drawings. In the drawings,

Figure 1: shows a schematic representation of a control network;

Figure 2: shows a schematic representation of a car; and

Figure 3: shows a flowchart. DETAILED DESCRIPTION

Figure 1 shows a control system 100 for a motorised vehicle and a car in particular. This may be a car having a combustion engine, an electromotor suitable for propelling the car or both. The control system 100 comprises a driver control unit 200, connected to a vehicle control unit via a vehicle control network 120 and receiving instructions therefrom. The vehicle control network 120 preferably comprises a bus system that is arranged for exchanging data in accordance with the LIN (Local

Interconnect Network) protocol. The driver control unit 200 is also contacted to a vehicle power supply network 130 that preferably comprises a battery.

The driver control unit 200 comprises a communication module 206, a processing module 202 comprising a memory module 204, a power supply module 208 and a current sensing module 250. Alternatively or additionally, the memory module 204 is located outside the processing module 202. The driver control unit 200 is connected to a first driving unit 152, a second driving unit 154 and a third driving unit 152 and arranged to control the driving units. In other embodiments, the driver control unit 200 is arranged to control more or less driving units, preferably between one and twelve or any number therein in between. In another embodiment, the driver control unit 200 is arranged to control even more driving units.

The driving units are arranged for driving air guiding flaps of a vehicle. More in particular, the driving units are arranged for moving the flaps between a first outer position and a second outer position. At least one of the driving units may be provided in one and the same housing as the driver control unit 200. Alternatively, the driving units and the driver control unit 200 are provided in separate housings.

The communication module 206 is arranged to communicate with the vehicle control unit 110 via a vehicle control network 120 and receiving instructions therefrom. The communication module 206 is arranged to be addressed by a single address in accordance with the LIN protocol. The i communication module 206 is arranged to derive multiple instructions for multiple driving units from one single message addressed to and received by the driver control unit 200. In such embodiment, different messages may be sent to one LIN address, each message carrying instructions for a different actuator. The different messages may optionally be sent in a round robin fashion. Each different message may comprise a different internal address dedicated to a particular actuator within the LIN address domain of the driver control unit 200.

The messages may be set one after the other. Alternatively, the messages carrying instructions for different actuators may be sent in one network message, addressed to the driver control unit 200. This message may carry one or more sub-messages, each message comprising an

instruction for a particular actuator and a sub-address, the sub-address addressing the particular actuator.

In another embodiment, the communication module 206 is arranged to be addressed by multiple addresses. In this embodiment, the communication module 206 is arranged to receive the messages addressed at the applicable addresses and forward the messages to the processing module 202. The addresses by which the driver control unit. 200 may be addressed may be stored in the memory module 204. The communication module 206 may retrieve the applicable addresses from the memory module 204 in order to determine what messages offered are to be processed by the driver control unit 200.

Each of the external addresses by which the driver control unit 200 may be addressed or at least a part of these external addresses is coupled to a different actuator. Rather than messages addressed to the driver control unit 200 being required to also provide an internal address for the applicable actuator, a specific actuator may be addressed directly by means of a dedicated external address. In this way, the driver control unit 200 is transparent to the vehicle control unit 110 such that the vehicle control unit 110 may directly address an actuator over the vehicle control network 120 by issuing a message with a specific address in accordance with conventions of the vehicle control network 120.

In yet another embodiment, the driver control unit is arranged to control current to the first driving unit 152, the second driving unit 154 and, optionally, the third driving unit 156 by receiving one single message over the vehicle control network 120 comprising one single instruction. This one single message is addressed to a single address to which the communication module 206 is arranged to listen and receive messages from. The

communication module 206 and/or the processing module 202 may be programmed such that if a message is received via this particular single address, the instructions comprised by the message are to be interpreted as instructions for the first driving unit 152, the second driving unit 154 and, optionally, the third driving unit 156.

Based on the single instruction, the first driving unit 152, the second driving unit 154 and, optionally, the third driving unit 156 may be provided with currents having substantially the same level. Alternatively, the levels of the supplied currents may be different. This may either be the case if the different driving units are to move flaps by different amount - or by similar amount, but have different responses to currents offered.

The processing module 202 is arranged to control the power supply module 208 in accordance with instructions received from the vehicle control unit 110, preferably via the communication module 206.

The power supply module 208 is arranged for providing a supply current to the various driving unit. The current to be supplied by the power supply module 208 is derived from the vehicle power supply network 130. The power supply module 208 is arranged to provide the supply currents in accordance with instructions received from the processing module 202. The power supply module 208 is in this embodiment connected to each driver with two conductors like wires. In one embodiment, the current is provided in a first direction for moving a flap in the direction of the first outer position an in a second direction for moving the flap in a direction of the second outer position. Alternatively or additionally, the power supply module is arranged for adjusting magnitude of the supply current. By adjusting the supply current, the intended speed of the flap may be adjusted. Furthermore, certain driving units may require less current than others.

The driver control unit 200 further comprises current sensing module 250. The current sensing module 250 is operatively connected to the conductive wires between the power supply module 208 and the driving units for sensing the current through at least one of the wires of each pair of wires. The current sensing module 250 comprises in the embodiment shown by Figure 1 a first current sensing unit 252 for sensing current supplied to the first driving unit 152, a second current sensing unit 254 for sensing current supplied to the second driving unit 154 and a third current sensing unit 256 for sensing current supplied to the third driving unit 156.

In another embodiment, the current sensing module 250 comprises less, possibly only one, current sensing unit for sensing currents provided to multiple driving units. The or each current sensing unit samples the current supplied to driving units. Hence, current sensing may take place in the digital or analogue domain. In case of sampling, the samphng frequency is preferably at least twice as high as the expected amount of revolutions per second, multiphed by an amount of commutators comprised by each electromotor and/or an amount of powered coils on the rotor.

The currents may be sensed by means of Hall sensors, resistive measurements, capacitive inductive couplings, any kind of electronic couplings, other, or a combination thereof. The current sensing elements may be provided separate from the power supply module 208 as depicted by Figure 1 or, alternatively or additionally, be implemented in the power supply module 208 itself. Hence, the current may be sensed as it is supplied, as it is provided through the one or more - preferably two - wires providing the current to the driving unit, in another way, or a combination thereof.

The driving units each comprise at least one electromotor - but may comprise more - and may optionally comprise a one or more drive trains for reducing drive speed and increasing torque or increasing drive speed. To this objective, the driving units may comprise gears, worm wheels (helical gears), other mechanical elements or a combination thereof. The driving units preferably do not comprise any electronic components.

Figure 2 shows a car 280 as a motorised vehicle comprising the system 100. The various components of 100 may be distributed over the car. At the back of the car, a battery 132 is provided for providing electrical power to the vehicle power supply network 130. In the middle of the car, the vehicle control unit 110 is located. The driver control unit 200 is located in the front of the car, preferably close to the first driving unit 152. The first driving unit 152 is connected to a flap of an active grill shutter (AGS) system 290. In another embodiment, the first driving unit 152 - or any of the other driving units - is arranged for adjusting the position of another air guiding flap, including, but not limited to any spoilers and the like for adjusting airflow at the back, front, top and/or bottom of the car 280 or a combination thereof.

As indicated, the first driving unit 152, the second driving unit 154 and the third driving unit 156 - and optionally more or less driving units - are preferably connected to the power supply module 208 by means of one or two conductive wires. In case only one conductive wire is provided, a return path for current may be provided via the framework of the car 280.

As the latter option may result in receiving a lot of noise in the connection between the driving units and the power supply module (and the sensed current, this is not a preferred embodiment. However, with the application of the right electronics, such embodiment is explicitly not excluded. As indicated above, the driving units preferably do not comprise any electronics. Yet, for preferred operation of the car 280, it is preferred the driver control unit 200 controls the driving units such that positions of the controlled flaps may be relatively accurately controlled.

To this objective, the current sensing module 250 is provided. The current sensing module 250 is coupled to the processing module 202 such that the processing module 202 is able to detect certain variations in currents supplied to the driving units to that objective, the current sensing module may comprise one or more high-pass or bandpass filters, one or more peak detectors, one or more zero crossing detectors, other electronic modules or a combination thereof.

The electromotors comprised by the driving units are preferably direct current motors and more in particular, brushed DC motors having three or more coils in the rotor. At each change of powering of the coils in the rotor, a variation occurs in the supply current provided to the driving unit. In conjunction with the current sensing module 250, the processing module 202 is arranged to count these variations. The number of variations counted may be used for determining an end position of the flap 290.

Figure 3 shows a flowchart 300 for receiving and processing of a data message through the vehicle control network 120 and for driving a driving unit such that the position of the flap 290 is adjusted to a position in accordance with instructions received. This will be discussed in further detail in conjunction with a flowchart 300 shown by Figure 3. The various parts of the flowchart 300 are briefly summarised in the hst below and will be discussed in further detail further below.

302 start process

304 receive data message

306 extract driver identification

308 extract driver instruction data

310 obtain current position data for flap 312 determine new position of flap

314 determine required movement of flap

316 determine amount of current variations during movement

318 determine current to be applied

320 apply determined current

322 count variations in supplied current

324 determined amount reached?

326 switch off current

328 store position of flap

330 end procedure

The procedure starts in a terminator 302 and proceeds to step 304 with the driver control unit 200 receiving data message from the vehicle control unit 110 via a vehicle control network 120 by means of the

communication module 206. The communication module 206 may transfer the whole data message to the processing module 202. Subsequently, the processing module 202 extracts an identifier of a driving module to which the data in the data message relates. Alternatively, the communication module 206 determines what driving unit the data in the receive message is related to.

In step 308, the processing module 220 obtains instruction data for the identified driving module from the receive message. The instruction may comprise an indication of a position of a particular flap, either as an absolute number or as a ratio between a first outer position and a second outer position. Alternatively or additionally, the instructions indicate a particular amount of movement of the flap.

In step 310, a current position of the flap 292 to be adjusted is obtained, preferably from the memory module 204. This position may be stored previously after receiving a previous adjustment instruction and/or execution thereof. Alternatively or additionally, a calibration step is provided to determine the position of the flap 292. To this end, the flap 292 is firstly moved to one of its outer positions. The processing module 202 is arranged to detect arrival of the flap 292 at an outer position when no more or less variations are sensed in the current provided to the applicable driving unit.

In this embodiment, information is stored in the memory module 204 for determining how many variations are to be counted in the supply current to arrive at a position in accordance with received instructions. For example, an amount of variations or an amount of revolutions to be counted are stored in the memory 204, optionally with an amount of variations per revolution. Such information may be pre-stored. In another embodiment, the information may be determined by moving the flap 292 between the first outer position and the second outer position and counting the amount of variations over this trajectory. In this way, an amount of variations can be coupled to a position between the first outer position and the second outer position.

In step 312, based on the instruction received, the processing module 202 determines a new position of the flap 292. In step 314, based on the current position of the flap 292 as retrieved from the memory module 204 and the received instruction, a required movement of the flap 292 is determined for arriving at a position in accordance with the received instructions. The required movement may be determined as such, as an actual movement of the flap or the electromotor comprised by the driving unit. Alternatively or additionally, the movement may be determined by means of other indicators.

Such indicators for an amount of movement may be variations in the supply current to be applied. With data on characteristics of the electromotor and in particular with a known amount of variations in the supply current per revolution of the rotor and with data on a transfer between movement of the rotor and movement of the flap 292, a number of variations in the supply current may be determined. These variations are to occur while the electromotor operates to move the flap 292 from its current position to the intended position.

In step 318, the current to be applied is determined. It is noted this step may also be determined prior to step 314 or prior to step 316. With determining the current, most important to be determined is the direction or the signage of the current to be applied. With the current applied in a first direction, the flap 292 will move towards the first outer position and with the current applied in a second direction, the flap 292 will move towards the second outer direction. Additionally, the magnitude of the current to be applied may be determined.

In one embodiment, the magnitude of the current apphed is always substantially the same. With substantially the same, an intended average of the magnitude of the current is indicated. As discussed above, variations may occur around, above or below the intended average.

Furthermore, as perfect current sources are not available, certain variations in the supply current may occur due to a state of the driving unit to which the current is provided. If the electromotor of the driving unit stalls, the actual current may increase above an intended level, as the voltage applied may change little.

With the magnitude and sign of the current to be applied determined and the amount of variations expected during the movement determined, the determined current is applied to the driving unit in step 320. Upon application of the current to the driving unit, the amount of variations in the driving current is counted. The number of variations in the driving current is sensed by means of the current sensing module 250 and in particular by the current sensing unit operatively connected to the conductors through which the applied current runs. In one embodiment, the current sensing module 250 comprises electronics for determining the variations in the supply current and for providing a digital and preferably binary signal to the processing module 202 at the moment a variation occurs. Alternatively, the occurrence of a variation is determined by the processing module 202.

Based on the sensing of variations, the processing module 202 counts the detected variations in step 322. In step 324, the counted amount is compared with the amount determined in step 316. If the counted amount of variations is substantially the same as the determined amount and preferably exactly the same, the procedure proceeds to step 326 in which the supply current to the driving unit is switched off. If the counted amount of variations is less than the amount determined in step 316, the process branches back to the 322 from step 324. After the current is switched off in step 326, the position of the flap at which the flap has arrived, is stored in the memory module 204. Subsequently, the procedure ends in terminator 330.

As indicated, the driver control unit 200 is preferably arranged for driving multiple driving units as actuators. The multiple driving units may drive one and the same flap, if driving of the flap requires more power than one single driving unit can provide. In such case, the driving units driving one and the same flap may be addressed using one single internal address, internal in the driver control unit. Furthermore, substantially synchronous operation of the driving units is preferred if they drive one and the same flap. The internal addresses of the driving units, allow the power supply module 208 to apply a supply current to a particular driving unit, either directly or with support of the processing module 202. Alternatively, two driving units driving one and the same flap are addressed using different (internal) addresses.

If different driving units drive different flaps, they are preferably addressed by means of different addresses, even if two different flaps are to be move substantially synchronously. Either addressed by a single address or by two different addresses, with two driving units driven simultaneously, the driver control unit 200 is arranged to detect errors in functionality of the driver units. In this embodiment, the driver control unit 200 provides supply current to the first driving unit 152 and the second driving unit 154. The current to the first driving unit 152 is sensed by means of the first current sensing unit 252 and the current trough the second driving unit 154 is monitored by means of the second current sensing unit 254. The first driving unit 152 and the second driving unit 154 are driven substantially synchronously, from and to substantially equivalent positions.

In supply currents to the first driving unit 152 and the second driving unit 154, the variations are sensed, determined and/or counted. Provided the first driving unit 152 and the second driving unit 154 are substantially the same, the amounts of variations in the supply currents to both driving units should be substantially the same over time. If this is not the case, it is determined the driving unit of which in the supply current the least amount of variations is counted is considered to malfunction. In particular if no variations are counted in a supply current, the connected and driven driving unit is considered to malfunction. In another

embodiment, the driving unit of which the amount of counted pulses is higher may be determined to malfunction and optionally to be defect.

If variations are detected in both supply currents and amount of variations differ by more than a pre-determined amount, the supply current in which the highest amount of variations is detected is decreased.

Additionally or alternatively, the supply current in which the lowest amount of variations is detected is increased.

In another embodiment, it is detected that a flap controlled by a driving unit is moved to on of its outer positions if an amount of variations counted to occur in the supply current counted per time unit decreases over time. In particular if no variations are sensed while a supply current is provided and sensed, it is determined an outer position of the flap is detected, as this is an indication the electromotor comprised by the driving unit does not make any revolutions. Alternatively, it may be determined the flap actuated is blocked otherwise. For example, a shutter of an AGS system may be blocked by a twig stuck between two shutters.

Expressions such as "comprise", "include", "incorporate", "contain", "is” and "have” are to be construed in a non-exclusive manner when interpreting the description and its associated claims, namely construed to allow for other items or components which are not explicitly defined also to be present. Reference to the singular is also to be construed in be a reference to the plural and vice versa.

In the description above, it will be understood that when an element such as layer, region or substrate is referred to as being "on” or “onto” another element, the element is either directly on the other element, or intervening elements may also be present.

Furthermore, the invention may also be embodied with less components than provided in the embodiments described here, wherein one component carries out multiple functions. Just as well may the invention be embodied using more elements than depicted in the Figures, wherein functions carried out by one component in the embodiment provided are distributed over multiple components.

A person skilled in the art will readily appreciate that various parameters disclosed in the description may be modified and that various embodiments disclosed and/or claimed may be combined without departing from the scope of the invention.