Relative Pose Determination of Primary and Secondary Winding Structures in Inductive Power Transfer System

Abstract

A method is disclosed for determining a relative pose between a primary winding structure and a secondary winding structure of a system for inductive power transfer to a vehicle. The method includes obtaining first output values generated by multiple receiving devices of a first radio direction finding system. The first radio direction finding system further includes a transmitting device. The receiving devices generate the output values in response to receiving a position signal transmitted by the transmitting device. The method includes determining a motion value of the vehicle. The method includes providing the obtained first output values and the motion value as input values to a model. The method includes determining a first relative pose based on the model. The method includes determining the relative pose based on the first relative pose.

Claims

1. A method for determining a relative pose between a primary winding structure and a secondary winding structure of a system for inductive power transfer to a vehicle, the method comprising: obtaining first output values generated by a plurality of receiving devices of a first radio direction finding system, wherein the first radio direction finding system further includes a transmitting device and wherein the plurality of receiving devices generates the output values in response to receiving a position signal transmitted by the transmitting device; determining a motion value of the vehicle; providing the obtained first output values and the motion value as input values to a model; determining a first relative pose based on the model; and determining the relative pose based on the first relative pose.

2. The method of claim 1 wherein: determining the first relative pose based on the model includes determining state variables based on the input values; and the first relative pose is determined based on at least one state variable.

3. The method of claim 2 wherein the first relative pose is determined based on exactly one state variable.

4. The method of claim 3 wherein the exactly one state variable is used as the first relative pose.

5. The method of claim 1 wherein a Kalman filter is used to determine the relative pose.

6. The method of claim 1 wherein the motion value is at least one of a velocity of the vehicle, a driving direction of the vehicle, and a steering wheel angle of the vehicle.

7. The method of claim 1 further comprising: obtaining second output values generated by a plurality of second receiving devices of a second radio direction finding system, wherein the second radio direction finding system further includes a second transmitting device and wherein the plurality of second receiving devices generates the second output values in response to receiving a second position signal transmitted by the second transmitting device; determining a further relative pose based on the obtained second output values; and selectively fusing the first relative pose and the further relative pose to generate a fused relative pose and determine the relative pose.

8. The method of claim 7 wherein the fused relative pose is selectively used as the relative pose.

9. The method of claim 7 wherein: in a first interval of distances between the primary and secondary winding structures, the first relative pose is used as the relative pose; in a second interval of distances between the primary and secondary winding structures, the fused relative pose is used as the relative pose; and the first and second intervals are non-overlapping.

10. The method of claim 9 wherein the distances of the second interval are smaller than the distances of the first interval.

11. The method of claim 7 further comprising: determining a first noise-related parameter of the obtained first output values; and determining a second noise-related parameter of the obtained second output values, wherein the fused relative pose is determined based on the noise-related parameters.

12. The method of claim 7 wherein the plurality of second receiving devices is provided by elements of a device for foreign object detection.

13. The method of claim 1 wherein the motion value is determined based on at least one of Global Navigation Satellite System (GNSS) signals, signals from an image sensor, and output values of a vehicle sensor.

14. The method of claim 1 further comprising transmitting information based on the motion value to a way-sided primary unit.

15. A system for determining a relative pose between a primary winding structure and a secondary winding structure of a system for inductive power transfer to a vehicle, the system comprising: a first radio direction finding system including a transmitting device and a plurality of receiving devices configured to generate first output values in response to receiving a position signal transmitted by the transmitting device; and a controller configured to: determine a motion value of the vehicle; determine a first relative pose using a model-based determination; and determine the relative pose based on the first relative pose, wherein the first output values and the motion value are input values of the model-based determination.

16. The system of claim 15 further comprising: a second radio direction finding system including a second transmitting device and a plurality of second receiving devices configured to generate second output values in response to receiving a second position signal transmitted by the second transmitting device, wherein the controller is configured to determine a further relative pose based on the second output values of the second radio direction finding system, and wherein the relative pose is selectively determined by fusing the first relative pose and the further relative pose.

17. The system of claim 16 further comprising: a device for foreign object detection, wherein the plurality of second receiving devices is provided by elements of the device for foreign object detection.

18. The system of claim 15 wherein the system is configured to transmit information based on the motion value from the vehicle to a way-sided primary unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0085] The present disclosure will become more fully understood from the detailed description and the accompanying drawings.

[0086] FIG. 1 is a schematic block diagram of a system for determining a relative pose between a primary winding structure and a secondary winding structure of a system for inductive power transfer.

[0087] FIG. 2 is a schematic block diagram of parts of system for determining a relative pose between a primary winding structure and a secondary winding structure of a system for inductive power transfer according to another embodiment.

[0088] FIG. 3 is a schematic flow diagram of a method for determining a relative pose between a primary winding structure and a secondary winding structure.

[0089] FIG. 4 is a schematic flow diagram of a method for determining a relative pose between a primary winding structure and a secondary winding structure according to another embodiment of the invention.

[0090] FIG. 5 is a schematic flow diagram of a method for determining a relative pose between a primary winding structure and a secondary winding structure according to another embodiment of the invention.

[0091] FIG. 6 is a schematic flow diagram of a method for determining a relative pose between a primary winding structure and a secondary winding structure according to another embodiment of the invention.

[0092] In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

[0093] In the following, the same reference numerals denote elements with the same or similar technical features.

[0094] FIG. 1 shows a schematic block diagram of a system 1 for determining a relative pose between a primary winding structure 2 and a secondary winding structure 3 of a system for inductive power transfer.

[0095] The system for inductive power transfer comprises a primary unit 4 which comprises the primary winding structure 2. Further, the primary unit 4 comprises a first receiving device 5a and a second receiving device 5b of a first radio direction finding system for determining a relative pose between set primary winding structure 2 and set secondary winding structure 3. Further, the system for inductive power transfer comprises a secondary unit 6 which is attached to a vehicle 7, in particular to a bottom side of the vehicle 7. The secondary unit 6 comprises the secondary winding structure 3. Further, the secondary unit 6 comprises a transmitting device 8 of the first radio direction finding system. The transmitting device 8 can comprise or be designed as an antenna structure. Further, each of the receiving devices 5a, 5b can also be designed as antenna structures or comprise such an antenna structure.

[0096] FIG. 1 shows that the first radio direction finding system comprises two receiving devices 5a, 5b. It is, however, possible that the first radio direction finding system comprises more than the shown to receiving devices 5a, 5b, in particular exactly four receiving devices or more than four receiving devices. These receiving devices 5a, 5b can be arranged at different positions with respect to a primary-sided coordinate system.

[0097] FIG. 1 shows an embodiment in which different receiving devices 5a, 5b are arranged with a predetermined distance along a longitudinal axis x of the primary-sided coordinate system. Further shown is a vertical axis z of said primary-sided coordinate system. A lateral axis (not shown) is oriented orthogonal to the longitudinal axis x and to the vertical axis z. This lateral axis can be oriented perpendicular to the drawing plane. It is e.g. possible that at least two or all receiving devices 5a, 5b of the primary unit 4 are arranged with a non-zero offset relative to each other along the longitudinal axis x. Alternatively or in addition, at least two or all receiving devices 5a, 5b of the primary unit 4 are arranged with a non-zero offset relative to each other along the lateral axis.

[0098] In one embodiment, at least two receiving devices of a first set comprising at least two receiving devices of the primary unit 4 are arranged with a non-zero offset relative to each other along the longitudinal axis x, wherein at least two receiving devices of a further set comprising at least two receiving devices of the primary unit 4 are arranged with a non-zero offset relative to each other along the lateral axis, wherein the first set comprises at least one receiving device which is not part of the further set.

[0099] Further, the primary unit 4 can comprise an evaluation unit 9, wherein the evaluation unit 9 can be designed as or comprise a microcontroller or an integrated circuit. This evaluation unit 9 can be connected to the receiving devices 5a, 5b by adequate signal transmission means, e.g. by a wire or by a wireless connection. By means of the evaluation unit 9, the first relative pose is determined depending on the output signals generated by the receiving devices 5a, 5b, in particular depending on at least one characteristic of said output signals. Such a process for the determination of the relative pose depending on the output signals are known to the skilled person.

[0100] Further, the primary unit 4 comprises a data receiving means 10 for receiving data signals transmitted by a vehicle-sided data transmitting means 11 in a wireless manner, e.g. via a Bluetooth™-based communication. In particular, a communication link can be established between the vehicle-sided data transmitting means 11 and the primary-sided data receiving means 10. The transmitting and receiving means can each comprise at least one antenna structure.

[0101] Further shown is a vehicle-sided control unit 12. By means of the vehicle-sided control unit 12 and the data transmitting means 11, at least one motion value of the vehicle 7 can be transmitted to the primary unit 4 by a corresponding data signal. Such a motion value can e.g. be the velocity of the vehicle 7 which can e.g. be determined by a velocity sensor (not shown), wherein said velocity sensor can be connected to the shown control unit 12.

[0102] Alternatively or in addition, the at least one motion value can comprise information on the driving direction of the vehicle 7, in particular in the world coordinate system. Further alternative or in addition, the at least one motion value can comprise or be provided by the steering wheel angle of the vehicle 7, wherein such a steering wheel angle can e.g. be determined by a sensor (not shown).

[0103] Further, the first relative pose is determined by the primary-sided evaluation unit 9 using a model-based determination, wherein input values of the model-based determination are provided by the output values of the receiving devices 5a, 5b and the at least one motion value which is transmitted from the vehicle 7 to the primary unit 4, in particular from the vehicle-sided control unit 12 to the primary-sided evaluation unit 9. The primary-sided evaluation unit 9 can be connected to the data receiving means 10 by adequate connecting means, e.g. in a wired or in a wireless manner.

[0104] It is also possible that the motion value, e.g. a velocity, of the vehicle 7 is determined based on the GNSS signal which is e.g. provided by a GNSS sensor (not shown) of the vehicle 7. The motion value can be determined by the vehicle-sided control unit 12 and be transmitted to the primary side, in particular to the primary-sided evaluation unit 9. Alternatively, the at least one motion value can be determined by the primary-sided evaluation unit 9, wherein signals for said determination are provided to the evaluation unit 9, e.g. by the vehicle 7, in particular by the vehicle-sided control unit 12.

[0105] FIG. 2 shows a schematic block diagram of parts of system for determining a relative pose between a primary winding structure 2 and a secondary winding structure 3 of a system for inductive power transfer according to another embodiment.

[0106] In FIG. 2, only the primary unit 4 of the system for inductive power transfer is shown. The primary unit 4 is essentially designed as the primary unit 4 shown in FIG. 1 and therefore, reference is made to the corresponding description. In contrast to the embodiment shown in FIG. 1, the primary unit 4 comprises an array 13 of detection windings 14 of a device for foreign object detection. For the ease of illustration, only one of the detection windings 14 is provided with a reference. Such a detection winding 14 can provide an antenna element for receiving a position signal, in particular the position signal generated and transmitted by the position signal transmitting device 8 (see FIG. 1). In this case, the position signal transmitted by the transmitting device 8 is received by the receiving devices 5a, 5b of the first radio direction finding system as well as by the detection windings 14 of the device for foreign object detection. Consequently, these detection windings 14 and the transmitting device 8 provide a further radio direction finding system for determining a relative pose between the primary winding structure 2 and the secondary winding structure 3.

[0107] The evaluation unit 9 can be connected to the detection windings 14 by adequate signal transmission means, e.g. by a wire or by a wireless connection. By means of the evaluation unit 9, the further relative pose is determined depending on the output signals generated by the detection windings 14, in particular depending on at least one characteristic of said output signals. Such a process for the determination of the relative pose depending on the output signals are known to the skilled person.

[0108] It is further possible to then determine a resulting relative pose by fusing the aforementioned first relative pose which is determined depending on the at least one motion value and the output signals generated by the receiving devices 5a, 5b of the first radio direction finding system and the further relative pose which is determined depending on the output signals generated by the detection windings 14 which provide receiving devices of the further radio direction finding system. This means that both, the first and the further relative pose is considered when determining the resulting relative pose.

[0109] FIG. 3 shows a schematic flow diagram of a method for determining a relative pose between a primary winding structure and a secondary winding structure.

[0110] Shown is the vehicle 7, wherein at least one motion value, in particular a speed value, a driving direction value and/or a steering wheel angle value, is determined in a motion value determining step 14. Further shown are receiving devices 5a, 5b of the first radio direction finding system, wherein the output values of said receiving devices 5a, 5b are determined in the output value determining step 15. The values determined in the steps 14, 15 are provided to a model-based determination of the relative pose between the primary winding structure 2 and the secondary winding structure 3, in particular as input values. In a determination step 16, said relative pose is determined.

[0111] FIG. 4 shows a schematic flow diagram of a method for determining a relative pose between a primary winding structure 2 and a secondary winding structure 3 according to another embodiment of the invention. In the first step S1, the position signal is generated and transmitted, e.g. by a vehicle-sided transmitting device 8 of the first radio direction finding system. In a second step S2, output values of receiving devices 5a, 5b of said first radio direction finding system our determined. In third step S3, at least one motion value of the vehicle 7 (see FIG. 1) is determined. In a fourth step S4, a first relative pose is determined using a model-based determination, wherein the input values of said model-based determination are provided by the values determined in the second and the third step S2, S3.

[0112] It is e.g. possible that the first relative pose is determined as an output of the model-based determination, wherein the model represents a relationship between the input values and the first relative pose. It is, however, also possible that the model represents a relationship between the input values and an output which is different from the first relative pose. In this case, the model can be used to determine the first relative pose as state variables, wherein the model describes a relationship between the input values and the state variables as well as the relationship between the state variables and an output of the model, in particular an observable or measurable output of the model. In particular in this case, the first relative pose can be determined as a non-observable/non-measurable state variable or depending on at least one such non-observable/non-measurable state variable.

[0113] The model can e.g. be a recursive model. In particular, the model can be provided such that the common feature-based determination of the relative pose is enabled. In this case, the model can e.g. provide a so-called state variable transition model which describes or represents the relationship, in particular a mathematical relationship, between the state variables at two different points in time. Further, the model can provide a so-called observation model which represents the relationship between state variables and the observation values, namely the at least one motion value and the output values of the receiving devices 5a, 5b. In a first sub step of the fourth step S4, predicted state variables can be determined by using the state variable transition model which is fed by previously determined estimated state variables, in particular state variables estimated at a previous point in time. In a second sub step of the fourth step S4, updated estimated state variables can be determined based on the predicted state variables determined in the first sub step and the observation values, in particular using the above-mentioned observation model. These updated estimated state variables then provide the aforementioned previously determined estimated state variables for the next sequence of steps S1 to S4.

[0114] The relative pose can be determined repeatedly, in particular with a predetermined frequency. This can be done by repeatedly performing the sequence of steps S1 to S4.

[0115] FIG. 5 shows a schematic flow diagram of a method for determining a relative pose between a primary winding structure 2 and a secondary winding structure 3 according to another embodiment of the invention. The sequence of the first step S1 to the fourth step S4 corresponds to the sequence illustrated in FIG. 4. Therefore, reference is made to the corresponding description. In fifth step S5, of further relative pose is determined based on output values generated by the receiving devices of the further radio direction finding system, e.g. by detection windings 14 of a foreign object detection system (see FIG. 2). In a six step S6, the relative pose, which can also be denoted as fused relative pose or resulting relative pose, is determined by fusing the first relative pose determined in the fourth step S4 and the further relative pose determined in the fifth step S6. Fusing can e.g. be performed by determining a mean value of the first and further relative pose, in particular a weighted mean value of said poses. It is e.g. possible to determine a noise-related parameter of the output signals provided by the receiving devices 5 a, 5B of the first radio direction finding system and of the receiving devices of the further radio direction finding system which represent the noise portion of said output signals, in particular in relation to the useful signal portion, and then determine the fused relative pose depending on these noise related parameters. In particular, a weight of the first or further relative pose in the determination of the weighted mean can increase with a decreasing noise value.

[0116] FIG. 6 shows a schematic flow diagram of a method for determining a relative pose between primary winding structure 2 and a secondary winding structure 3 according to another embodiment of the invention. The sequence of the first step S1 to the fourth step S4 corresponds to the sequence illustrated in FIG. 4. Therefore, reference is made to the corresponding description. The sequence of the fifth step S5 to the sixth step S6 corresponds to the sequence illustrated in FIG. 5. Therefore, reference is made to the corresponding description. In contrast to the embodiment shown in FIG. 4, the method comprises the decision step DS. In the decision step, a distance between the primary winding structure 2 and the secondary winding structure 3 is determined, in particular depending on the first relative pose determined in the fourth step S4. If this distance value is within a first distance interval, the relative pose is determined as this first relative pose. If this distance value is within a further distance interval, the sequence of the fifth and the six step S5, S6 is performed and the relative pose is determined as the fused relative pose as outlined above. If this distance value is neither within the first nor the further distance interval, no relative pose is determined and an out of range information is generated. The distance values of the first distance interval can be higher than the distance values of the further distance interval.

[0117] The sequence of steps S1, S6 shown in the FIGS. 4 to 6 do not necessarily define the time sequence of said steps S1, S6. It is in particular possible that the at least one motion value which is determined in the third step S3 is determined simultaneously to the output values of the receiving devices 5a, 5b determined in the second step S2. It is further possible that the output values of the receiving devices of the further radio direction finding system which are determined in the fifth step S5 are determined simultaneously to the determination performed in the second step S2 and/or the determination performed in the third step S3. It is further possible that the determination of the first relative pose in the fourth step S4 is performed simultaneously to the determination of the further relative pose in the six step S6.

[0118] The phrase “at least one of A, B, and C” should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”