Remote control for automotive applications

Abstract

A method for remote controlling an object with a remote-control unit is provided. At least a first surface S.sub.1, S.sub.2, S.sub.i is defined in a first coordinate system. At least a first function of the object is associated to the first surface S.sub.1, S.sub.2, S.sub.i. A second coordinate system is defined at the position of the remote-control unit. A static pointing vector 28 is defined in the second coordinate system. It is then determined whether the pointing vector points towards the first surface S.sub.1, S.sub.2, S.sub.i. If so, the object is enabled to selectively activate the first operation upon receipt of an activation command.

Claims

1. A method for remote controlling an object with a remote-control unit, comprising the steps of: defining at least a first surface (S.sub.1, S.sub.2, S.sub.i) in a first coordinate system, wherein the first coordinate system is the object's coordinate system, associating at least a first function (M.sub.1, M.sub.2, M.sub.i) of said object to said first surface (S.sub.1, S.sub.2, S.sub.i), defining a second coordinate system at the position of the remote-control unit, wherein the second coordinate system is the remote-control unit's coordinate system, defining a static pointing vector in said second coordinate system, determining if the pointing vector points towards said first surface (S.sub.1, S.sub.2, S.sub.i), generating at least a first electromagnetic field by the object, providing predicted information about the spatial orientation of an electric and/or magnetic field vector of said first electromagnetic field at the position of the remote-control unit in the first coordinate system, measuring the spatial orientation of the predicted magnetic and/or electric field vector at the position of the remote-control unit by the remote-control unit in said second coordinate system, obtaining the representation of the pointing vector in the first coordinate system from an annular relation between the measured spatial orientation and the predicted spatial orientation of the electric and/or magnetic field vector, and activating said first function (M.sub.1, M.sub.2, M.sub.i) by the object upon receipt of an activation command only if the pointing vector points towards said first surface (S.sub.1, S.sub.2, S.sub.i).

2. The method of claim 1, further including the step of: determining the position of the remote-control unit in the object's coordinate system.

3. The method of claim 1 further including the steps of: associating at least a second function (M.sub.2) to a second surface (S.sub.2), activating said second function (M.sub.2) by the object upon receipt of an activation command, only if the pointing vector points towards said second surface (S.sub.2).

4. The method of claim 3 wherein a single activation command enables to activate at least the first and second functions (M.sub.1, M.sub.2, M.sub.i) of the object and only those of said functions (M.sub.1, M.sub.2, M.sub.i) are activated which are associated to surfaces (S.sub.1, S.sub.2, S.sub.i) to which the pointing vector points to.

5. The method of claim 3 further including the step of: testing if the pointing vector points towards the first surface (S.sub.1) and the second surface (S.sub.2) and at least one of: activating the first function (M.sub.1) only if the remote-control unit is closer to the first surface (S.sub.1) then to the second surface (S.sub.2) and activating the second function (S.sub.2) only if the remote-control unit is closer to the second surface (S.sub.2) than to the first surface (S.sub.2).

6. The method of claim 1 wherein a minimum and/or a maximum distance is associated to the at least one first surface (S.sub.1, S.sub.2), and wherein that the activation step further comprises testing if the distance of the remote-control unit to a reference point in the first coordinate system or a third coordinate system is larger than the minimum distance and/or smaller than the maximum distance and activating the function (M.sub.1, M.sub.2, M.sub.i) associated to the at least one first surface (S.sub.1, S.sub.2, S.sub.i), only if the distance is larger than the minimum distance and/or smaller than the maximum distance.

7. The method of claim 1 further including the step of: defining a front and a rear side of the first surface (S.sub.1, S.sub.2, S.sub.i) and activating the first function (M.sub.1, M.sub.2, M.sub.i) only if the pointing vector (28) points to a predefined of said first and rear sides.

8. The method of claim 1 wherein the pointing vector is visualized by a light beam being emitted by the remote-control unit in the direction of the pointing vector.

9. The method of claim 1 further including the step of: visualizing or otherwise indicating if the pointing vector points towards said first surface (S.sub.1, S.sub.2, S.sub.i) prior to receiving an activation command by at least one of: a. illuminating an item of the object, wherein the item is associated to the first function, if the pointing vector points to the first surface (S.sub.1, S.sub.2, S.sub.i), b. activating an indication means of the remote-control unit, wherein the indication means is associated to the first function, if the pointing vector points to the first surface (S.sub.1, S.sub.2, S.sub.i).

10. The method of claim 1 wherein the first function (M.sub.1, M.sub.2, M) is only activated if the pointing vector points towards a predefined side of the first surface.

11. The method of claim 1 further comprising the steps of: transmitting at least one of the measured electric, magnetic field vector to the object, the predicted electric, and magnetic field vector to a controller of the remote-control unit, determining the rotation for aligning the first and second coordinate systems, applying the determined rotation to the representation of the pointing vector in the second coordinate system to thereby obtain its representation in the first coordinate system, determining, if the pointing vector points towards said at least one first surface (S.sub.1, S.sub.2, S.sub.i) based on its representation in the first coordinate system.

12. The method of claim 1 further comprising the steps of: measuring the orientation of the at least one external reference vector by the remote-control unit in the second coordinate system, compensating for imperfections in the measurement of the orientation of the at least one external reference vector by the remote-control unit in the second coordinate system based on the orientation of the at least one external reference vector measured by the remote-control unit and an assumption about the orientation of the at least one external reference vector in the first coordinate system.

13. The method of claim 1 wherein the determining step further comprises: determining the orientation of at least one external reference vector by the object in the first coordinate system, measuring the orientation of the at least one external reference vector by the remote-control unit in the second coordinate system, determining the rotation for aligning the at least one an external reference vector in the representation in the first coordinate system as measured by the object with the at least one external reference vector in the representation in the second coordinate system as measured by the remote-control unit, and applying the determined rotation to the representation of the pointing vector in the second coordinate system to thereby obtain its representation in the first coordinate system, and determining, if the pointing vector points towards said at least one first surface (S.sub.1, S.sub.2, S.sub.i)) based on its representation in the first coordinate system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.

(2) FIG. 1 shows a system with an object and a remote-control unit.

(3) FIG. 2 shows a flow diagram of a method for using the system.

(4) FIG. 3 shows a flow diagram of the determining step.

(5) FIG. 4 shows a flow diagram of an alternative determining step.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) FIG. 1 shows an object 10 having a first function and optionally a second function or further functions, symbolized by actuators M.sub.1, M.sub.2 and M.sub.i, respectively (i being an integer greater two). For example, if the object is a car, the first function could be to lock/unlock the left front door. M.sub.1 would then represent the drive for actuating the door lock. M.sub.2 could e.g. represent a drive for operating a trunk lid. Thus, the second function could be opening or closing a trunk by moving the trunk lid up or down. In the example, the object 10 has i functions, where i is an integer greater 2, but of course a single function that can be controlled by a remote-control unit 10 is sufficient to make use of the invention. In other words, generally i satisfies the relation i1.

(7) For each function M.sub.1, M.sub.2, M.sub.i, a surface S.sub.1, S.sub.2 and S.sub.i is defined in the first coordinate system 19. The surfaces S.sub.1, S.sub.2 and S.sub.i are associated to the respective functions. One could as well say that each function M.sub.j is linked with a surface S.sub.j (ji). The information about the linkage could e.g. be stored in a lookup table. The surfaces S.sub.j may be selected to correspond in practice with the linked function, e.g. if the function M.sub.2 is to raise or lower a window the surface S.sub.2 being linked with said function could be a surface of said window. Or if a function M.sub.j is to open or close a trunk lid, the linked surface S.sub.j could be the trunk-lid's shell surface. The surfaces S.sub.j may not necessarily exactly represent the shell surface; it can as well be a projection of the item to control onto e.g. a plane (see Bronstein Semedjajev, Handbook of Mathematics, 5.sup.th Ed. Springer Berlin Heidelberg 2007, Chapt. 3.3.1 and 3.5.4.3,). This reduces memory requirements and the numerical effort.

(8) The first object 10 defines a first reference system, i.e. a first coordinate system 19 being attached to the object 10. In this sense the first coordinate system 19 is the object's coordinate system. Its origin and orientation can be set arbitrarily, provided it does not move relative to the object.

(9) A controller 15 of the object 10 is connected to four antennas 11 to 14 for emitting and/or receiving RF-signals (one of the four antennas is optional, additional antennas enable to enhance the precision of a distance measurement). The controller is as well connected to the actuators M.sub.1, M.sub.2 to M.sub.i for controlling the first and second functions in response to signals provided by a remote-control unit 20.

(10) The remote-control unit 20 comprises as well a controller 25 which is connected to an antenna 21, 22 for receiving and/or transmitting RF-signals to thereby communicate with the object 10. The remote-control unit 20 defines a second reference system, i.e. a second coordinate system 29 being attached to the remote-control unit may be defined. If the remote-control unit is carried around by a user or pivoted, the second coordinate system 29 moves relative to the first coordinate system 19 and a pointing vector 28 being defined in the second coordinate system moves accordingly. To ease directing the pointing vector 28 to a target, e.g. to one of the surfaces S.sub.j, the remote-control unit may comprise a light source for emitting a light beam 30, being aligned or at least parallel to the direction of the pointing vector 28. A user may provide an activation command by actuating an input receiving means 27, which is symbolized in the figure by a switch 27.

(11) For activating a particular function M.sub.j, a user points with the pointing vector 28 to the corresponding surface S.sub.j and provides an activation command via the input receiving means. The orientation of the pointing vector 28 is determined by at least one of the controllers 15, 25 and if the pointing vector 28 points to one of the surfaces S.sub.j, the associated function M.sub.j is activated, e.g. energized.

(12) A method for determining if the pointing vector 28 points to one of the surfaces S.sub.j is shown in FIG. 2. In a first step 100 the first and second coordinate systems 19, 29 and the pointing vector 28 are defined. Next, e.g. upon an input provided to said input receiving means 27 the position {right arrow over (p)}.sub.r.sub.1 of the pointing vector 28 and its orientation {right arrow over (v)}.sub.r.sub.1 are determined in the first coordinate system (step 110). Based on the position {right arrow over (p)}.sub.r.sub.1 and the orientation {right arrow over (v)}.sub.r.sub.1 it is determined if the pointing vector 28 points towards one of the surfaces S.sub.j. Only if the pointing vector 28 points to one of the surfaces S.sub.j, the function M.sub.j being associated to said surface S.sub.j is activated. This is symbolized by step 120, referred to as activation step.

(13) The determining step 110 may comprise at least some of the method steps shown in FIG. 3. In particular, the determining step 110 may comprise providing a first observable vector field by the object 10 or at least in the first coordinate system as indicated by box 111. Next, at the position {right arrow over (p)}.sub.r of the remote-control unit (e.g. of the pointing vector 28), the direction of a field vector {right arrow over (f.sub.2)}({right arrow over (p)}.sub.r) of said vector field is measured by the remote-control unit 20 in the second coordinate system (box 112). This can be obtained by corresponding directional antennas 21, 22. Only two antennas are depicted, but of course at least three are preferred to fully determine spatial orientation of the vector field at the position of the remote control unit. This measured field vector {right arrow over (f.sub.2)}({right arrow over (p)}.sub.r) is compared (represented by box 113) to a predicted field vector {right arrow over (f.sub.1)}({right arrow over (p)}.sub.r) at the position of the remote-control unit 20 to thereby determine the rotation R for aligning the first coordinate system 19 with the second coordinate system 29, briefly R can be determined from
R{right arrow over (f.sub.1)}({right arrow over (p)}.sub.r)={right arrow over (f.sub.2)}({right arrow over (p)}.sub.r),(1)
wherein R is the corresponding rotary matrix, {right arrow over (f.sub.1)}({right arrow over (p)}.sub.r) is the predicted field vector at {right arrow over (p)}.sub.r and {right arrow over (f.sub.2)}({right arrow over (p)}.sub.r) is the measured field vector at {right arrow over (p)}.sub.r. Again, the field vectors {right arrow over (f.sub.1)}({right arrow over (p)}.sub.r), {right arrow over (f.sub.2)}({right arrow over (p)}.sub.r) can be considered to be normalized, because they must have the same length.

(14) Preferably, first the location {right arrow over (p)}.sub.r of the remote-control unit 20 in the first coordinate system 19 and the corresponding measured field vector {right arrow over (f.sub.2)} are determined as well in step 111. For example the location {right arrow over (p)}.sub.r of the remote-control unit 20 in the first coordinate system can be determined using trilateration: To this end each of the antennas 11 to 14 (see FIG. 1) broadcasts a signal which is received by the remote-control unit 20, e.g. using at least one of the antennas 21, 22. Based on the signal strength indicator (RSSI-value) of the signals the distance from the remote-control unit to the respective antenna 11 to 14 is calculated. The distances d.sub.1 to d.sub.4 enable to locate the remote control unit 20 in the first coordinate system and thereby {right arrow over (p)}.sub.r.sub.1. The signals for the distance measurements can be transmitted sequentially to be able to clearly distinguish them. Alternatively a clear distinction is possible if the signals are sent at different frequencies.

(15) In an alternative embodiment the method step 110 may comprise measuring a vector of an external vector field by the remote-control unit and by the object (box 115, see FIG. 4) again these measurements can be represented by field vectors {right arrow over (f.sub.1)}, {right arrow over (f.sub.2)}. For example, both could be representative for the direction of the (earth) gravity field. The gravity field can be measured very easily by acceleration sensors, provided that the acceleration vector of the object or the remote control unit relative to the earth is zero or known. It may be assumed, that the two measured gravity field vectors are parallel and the equation (1) can be solved for the angles , , and . Only for large distances the angle between the two measured field vectors has to be included in the calculation (by a corresponding additional rotation), but at these distances the object is likely out of sight and the user thus cannot direct the pointing vector to a surface being associated to a surface of the object. If not already known at the position {right arrow over (p)}.sub.r of the remote-control unit (i.e. of the pointing vector) is measured as well. These measured field vectors {right arrow over (f.sub.1)}, {right arrow over (f.sub.2)} are compared (box 116) to thereby determine the rotation R for aligning the first coordinate system 19 with the second coordinate system 29, briefly R can be determined from
R{right arrow over (f.sub.1)}={right arrow over (f.sub.2)}.

(16) As soon as the rotation R is determined, it can be determined very easily if the pointing vector points to at least one of the surfaces S.sub.j. Of course the method may comprise the determining step as explained with respect to FIG. 3 and the determining step as explained with respect to FIG. 4. In this case one obtains two matrices and thus two values for each angle of rotation. The angles can be compared and accepted only if the difference between the angles is below a predefined maximum. In this case one may continue e.g. with the mean of the corresponding angles or with the result of one of the determining steps (optional step 117).

LIST OF REFERENCE NUMERALS

(17) 10 object, e.g. a car, boat, machine 11 antenna 12 antenna 13 antenna 14 antenna 15 controller 19 first coordinate system 20 remote-control unit 21 antenna 22 antenna 25 controller 27 input receiving means (e.g. switch) 28 pointing vector 29 second coordinate system 30 light beam 100 definition step 110 determining step 111 providing a first observable vector field 112 measuring the direction of a field vector 113 determining the rotation R for aligning the first coordinate system 19 with the second coordinate system 29 115 measuring a vector of an external vector field by the remote-control unit and by the object 116 comparing the measured field vectors to determine the rotation R for aligning the first coordinate system 19 with the second coordinate system 29 117 comparing the angles of rotation (optional) 120 activation step M.sub.1 first function M.sub.2 second function M.sub.i i.sup.th function S.sub.1 first surface S.sub.2 second surface S.sub.i i.sup.th surface d.sub.1 distance d.sub.2 distance d.sub.3 distance d.sub.4 distance