TOY VEHICLE HAVING A YAW RATE SENSOR

Abstract

A toy vehicle has wheels and a steering unit. The steering unit includes a steering drive acting on at least one of the wheels and a control unit acting on the steering drive. The at least one wheel that is acted upon by the steering drive is mounted on a chassis of the toy vehicle so as to be steerable with a variable steering angle. The steering unit includes a yaw rate sensor for determining a yaw rate of the toy vehicle about its vertical axis and is free of a sensor for determining the steering angle. The steering drive, the control unit, and the yaw rate sensor together form a control loop for setting the yaw rate to a specified target value. A toy vehicle system includes a toy vehicle and a track. The control unit includes at least one sensor for detecting the track.

Claims

1. A toy vehicle comprising: a plurality of wheels; a steering unit having a steering drive configured to act on at least one first wheel of said plurality of wheels and a control unit configured to act on said steering drive; wherein said at least one first wheel is steerably mounted on a chassis of the toy vehicle with a changeable steering angle; said steering unit further having a yaw rate sensor for calculating a yaw rate of the toy vehicle about a vertical axis of the toy car and having no sensor for calculating the steering angle; and, said steering drive, said control unit, and said yaw rate sensor together forming a regulating loop for setting the yaw rate to a predetermined target value.

2. The toy vehicle of claim 1, wherein said control unit includes a receiver for control signals of a remote control; and, said control unit is configured to derive the target value for the yaw rate from the control signals received in said receiver.

3. The toy vehicle of claim 1, wherein said control unit includes at least one track sensor for detecting a predetermined track; and, said control unit is configured to derive the target value for the yaw rate from sensor signals calculated by said track sensor.

4. The toy vehicle of claim 3, wherein said control unit is configured to derive the target value for the yaw rate from the sensor signals calculated by said track sensor such that the toy vehicle follows the predetermined track.

5. The toy vehicle of claim 3, wherein said control unit is configured to derive specific driving events from the sensor signals calculated by said track sensor.

6. The toy vehicle of claim 5, wherein the specific driving events include at least one of braking, acceleration, and affecting the yaw rate.

7. The toy vehicle of claim 3, wherein said track sensor for detecting the predetermined track is an IR sensor with an IR emitter and with an IR receiver.

8. The toy vehicle of claim 1, wherein the toy vehicle is a replica car with at least two steerable wheels and with at least two non-steerable wheels.

9. The toy vehicle of claim 1, wherein the toy vehicle is a replica motorcycle with one steerable wheel and with one non-steerable wheel.

10. The toy vehicle of claim 9, wherein the toy vehicle configured as a replica motorcycle has a controlled support device for specifying an angle of inclination of the vertical axis relative to a surface normal of a track to be driven on.

11. The toy vehicle of claim 10, wherein said steering unit includes a pivoting drive acting on said support device; said support device subject to action of said pivoting drive is pivotably mounted on said chassis of the toy vehicle with a changeable angle of pivoting; said steering unit includes a yaw rate sensor for calculating a yaw rate of the toy vehicle about a longitudinal axis of the toy vehicle and thus has no sensor for calculating the angle of pivoting; and, said pivoting drive, said control unit, and said yaw rate sensor together form a regulating loop for setting the yaw rate to a predetermined target value.

12. A toy vehicle system comprising: a toy vehicle having a plurality of wheels, a chassis, and a steering unit having a steering drive configured to act on at least one first wheel of said plurality of wheels and a control unit configured to act on said steering drive; wherein said at least one first wheel is steerably mounted on said chassis of the toy vehicle with a changeable steering angle; said steering unit further having a yaw rate sensor for calculating a yaw rate of the toy vehicle about a vertical axis of the toy car and having no sensor for calculating the steering angle; said steering drive, said control unit, and said yaw rate sensor together forming a regulating loop for setting the yaw rate to a predetermined target value; a track for said toy vehicle; said control unit including at least one sensor for detecting said track.

13. The toy vehicle system of claim 12, wherein said sensor for detecting said track is an IR sensor and said track is provided with an IR-sensitive orientation pattern.

14. The toy vehicle system of claim 13, wherein said IR-sensitive orientation pattern includes a pattern of alternating light and dark triangular sections extending transversely over said track.

15. The toy vehicle system of claim 13, wherein said IR-sensitive orientation pattern includes a pattern of alternating light and dark lines extending transversely over said track.

16. The toy vehicle system of claim 13, wherein said IR-sensitive orientation pattern is covered by an IR-permeable and visually opaque covering layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0023] The invention will now be described with reference to the drawings wherein:

[0024] FIG. 1 shows, in a perspective schematic illustration, a toy vehicle according to the prior art with a steering drive, a control unit, and a potentiometer for indirectly detecting the steering angle;

[0025] FIG. 2 shows, in a perspective schematic illustration, a first modification according to the disclosure of the toy vehicle as a replica car with a yaw rate sensor instead of the potentiometer;

[0026] FIG. 3 shows a variant of the toy vehicle according to FIG. 2 with gear-segment steering instead of rack-and-pinion steering;

[0027] FIG. 4 shows, in a schematic illustration, a toy vehicle system according to the disclosure with a toy vehicle according to FIG. 2 or 3, with an IR-sensitive track and with a smartphone as a remote control;

[0028] FIG. 5 shows, in a schematic side view, an alternative embodiment of the toy vehicle as a replica motorcycle with a support device for setting an angle of inclination of the vehicle vertical axis; and,

[0029] FIG. 6 shows, in a front view, the toy vehicle according to FIG. 5 driving in a curve and an angle of inclination set via the support device.

DETAILED DESCRIPTION

[0030] FIG. 1 shows, in a schematic perspective illustration, a toy vehicle 1 according to the prior art, wherein the toy vehicle 1 is a replica car. The body, traction drive, rear wheel suspension, or the like are not illustrated here for greater visibility. The toy vehicle 1 has a longitudinal axis x fixed to the vehicle and a vertical axis z fixed to the vehicle. In the usual driving mode, the toy vehicle 1 moves in the direction of its longitudinal axis x and thus also performs yawing movements about the vertical axis z with a yaw rate .sub.z as a result of a steering movement.

[0031] The toy vehicle 1 has two front steerable wheels 2 and two rear driven non-steerable wheels 3 situated on a rigid axle. The front wheels 2 are steerably mounted with steering knuckles on a chassis 16 of the toy vehicle 1 such that they can be set at a desired steering angle about steering axes 27 running in a vertical direction. The choice of the steering angle results, when the toy vehicle 1 is driving in the direction of its longitudinal axis x depending on the current speed, in a corresponding yaw rate .sub.z about the vertical axis z, wherein the yaw rate .sub.z when driving in a straight line equals zero and is non-zero when driving in a curve. The toy vehicle 1 includes a steering drive 4 which acts on the steered wheels 2 and on which in turn a control unit 5 acts. The control unit 5 includes a receiver 7 (only indicated schematically) for the control signals of an emitter (not illustrated). These control signals are converted in the control unit 5 for controlled actuation of the steering drive 4. The steering drive 4 includes an electric steering motor 20 which sets the steering angle of the front wheels 2 via a steering transmission 17. For this purpose, the steering transmission 17 includes a pinion 18 which engages in a rack 19 connected to the steering knuckles of the front wheels 2. A lateral pushing movement of the rack 19 caused thereby orients the front wheels 2 at a desired steering angle .

[0032] For feeding back the abovementioned steering movement, the steering unit shown here according to the prior art is equipped with a sensor for calculating the steering angle . According to the principle of a servo drive, the sensor is integrated into the steering transmission 17 and is coupled, in its form shown here of a potentiometer 15, to the steering movement of the wheels 2 via an independent set of gears. According to an indirect steering angle detection, the steering angle achieved can be inferred from the starting value of the potentiometer 15, from the known transmission ratio of the steering transmission 17, and from the collectively known steering kinematics. The steering angle achieved is fed back from the potentiometer 15 to the control unit 5 in the form of the starting value, as a result of which proportional control is formed.

[0033] FIG. 2 shows, in a perspective illustration, a toy vehicle 1 as a modification according to the disclosure of the toy vehicle 1 according to FIG. 1. Unless expressly stated otherwise, the same features, properties, and actions exist, the same reference signs being used for the same features.

[0034] The action of the steering motor 20 via the steering transmission 17 on the setting of the steering angle of the front wheels 2 is as described above. However, there is no potentiometer 15 (FIG. 1) or a different sensor for calculating the steering angle and feeding it back into the control unit 5. The steering angle which is actually present or set during operation is not known in the control unit 5 and also not required according to the disclosure.

[0035] Rather, the steering unit of the toy vehicle 1 according to the disclosure includes, instead of the steering angle sensor, a yaw rate sensor 6 for calculating the currently present yaw rate .sub.z of the toy vehicle 1 about its vertical axis z. The yaw rate sensor 6 is interconnected together with the steering drive 4 and the control unit 5 to form a regulating loop via which the yaw rate .sub.z of the toy vehicle 1 is set to a predetermined target value. For this purpose, a comparison is made in the control unit 5 of the actual yaw rate .sub.z, calculated by the yaw rate sensor 6, with the predetermined target value. The regulating deviation calculated from this comparison is converted in the control unit 5 into a corresponding activation of the steering drive 4, which results in a reduction or elimination of the regulating deviation by resetting the steering angle of the steerable wheels 2. In the present case, a P-controller (proportional controller) is used for this which allows a certain regulating deviation which can be tolerated in practice. For higher regulation demands, however, a different controller, for example a PID-controller (proportional-integral-differential controller) or an even more complex regulating system, can also be chosen.

[0036] In the embodiment according to FIG. 2, the situation of driving in a straight line is shown, wherein the associated operating method according to the disclosure is described below. The steerable wheels 2 have a steering angle of 0 such that they are oriented essentially parallel to the longitudinal axis x. The associated yaw rate .sub.z equals 0. If the receiver 7 receives a control signal for driving in a straight line from a remote control 8 illustrated in FIG. 4, the target value for the yaw rate .sub.z is fixed at 0, which corresponds to the desired driving in a straight line. If the toy vehicle is actually driving in a straight line, there is no regulating deviation and the abovementioned regulating loop does not engage. If, however, the vehicle is deflected from the fundamental driving direction with its longitudinal axis x, because for example of uneven ground or any other disturbance, this is accompanied by a yaw rate .sub.z0 which is detected by the yaw rate sensor 6 and which means that there is a regulating deviation. According to the regulating deviation, the regulating loop revises the steering (changing the unknown steering angle ) until driving in a straight line with the associated actual yaw rate .sub.z=0 as the target value is restored. In the case of just P-control, a deviation of the orientation of the longitudinal axis x from the prior orientation can occur, which however is usually sufficient when steadying the vehicle. In the case of higher regulation requirements where, for example, a return to the original orientation of the longitudinal axis x (heading hold) is involved, the use of a PID-control is expedient. In the same way, controlled driving in a curve with a yaw rate .sub.z0 as the target value can also be achieved.

[0037] In any case, a potentiometer 15 (FIG. 1) plus an associated drive or a different sensor for calculating the steering angle have been completely omitted. The actual magnitude of the current steering angle is not significant for the functioning of the regulating loop according to the disclosure. The yaw rate sensor 6 is moreover an electronic component with no mechanically moved parts and a minimal overall structural space. It is illustrated schematically here outside the control unit 5 for good visibility. In practice, however, it is integrated into the control unit 5 without utilizing additional structural space. The arrangement according to the disclosure which is shown has an overall small volume, is mechanically robust, cost-effective, and simple, and is thus suitable in particular for miniature toy vehicles for use, for example, in the living room or on a table top.

[0038] FIG. 3 shows a variant of the toy vehicle 1 according to FIG. 2 with a slightly modified steering mode 17. The steering knuckles of the steerable front wheels 2 are connected not to a rack 19 (FIG. 2) but to in each case one gear segment 22 in the shape of a segment of a circle and meshing with which is a common pinion 21, situated between them, with a vertical axis of rotation. In the remaining features and reference signs, the embodiment according to FIG. 3 coincides with those according to FIG. 2.

[0039] By way of example, the situation of a steering deflection of the front wheels 2 with a steering angle 0 when driving off is illustrated in FIG. 3, wherein here too an associated operating method according to the disclosure is described below. As soon as the vehicle has started to move, the steering deflection causes the toy vehicle 1 to drive in a curve which in turn, depending on the current speed, entails a corresponding yaw rate .sub.z about the vertical axis z. When the vehicle begins to drive away from a standstill, the initial steering angle is not important. The toy vehicle 1 can be placed on its track with any desired steering angle , for example, according to FIG. 3. As long as it is not in motion, the actual yaw rate .sub.z=0. However, as soon as the vehicle is set in motion via its traction drive which is present but not illustrated, the deflected wheels 2 cause the vehicle initially to drive in a curve with a corresponding non-zero yaw rate .sub.z which is detected immediately by the yaw rate sensor 6 and compared with the predetermined target value in the control unit 5. If this target value equals 0 (driving in a straight line desired), the regulating loop according to the disclosure revises the steering to such an extent that driving in a straight line with a yaw rate .sub.z=0 is actually detected by the yaw rate sensor 6 and fed into the control unit 5. Only minimal travel is required for this. The process of adjusting the vehicle to driving in a straight line from the initial position of the deflected wheels 2 takes place so quickly that it is virtually unnoticed by the user. Analogously, the same of course also applies for adjusting the vehicle to driving in an intended curve in which the target value of the yaw rate .sub.z deviates from 0.

[0040] FIG. 4 shows, in a perspective synoptic illustration, a toy vehicle system according to the disclosure which includes a toy vehicle 1 according to FIG. 2 or 3, a road with a track 12, and a remote control 8. In addition to the equipment illustrated in FIGS. 2 and 3, the toy vehicle 1 is also provided with at least one sensor 9 for detecting the predetermined track 12. This sensor is here an IR sensor with an IR emitter 10 and with an IR receiver 11.

[0041] A straight road segment of the track 12 is shown by way of example here. It can, however, also be a curve segment, a pit lane segment, or the like, it then being possible for any desired tracks to be composed from such segments. However, a one-part track 12 ready formed as a complete track can also be provided. The track 12 is provided with an IR-sensitive orientation pattern 13 which corresponds with the IR sensor. Various forms can be considered for the configuration of the orientation pattern 13. In the embodiment shown, it includes a pattern of alternating (in the IR range) light and dark triangles extending transversely over the track 12. Triangular sections of these triangles extend over the track 12, while the apices of the triangles, which are unimportant for orientation purposes, have been omitted for the sake of simplicity. In a more accurate definition, it is thus a pattern of alternating light and dark triangular sections 23 or trapeziums extending transversely over the track 12. The IR-sensitive orientation pattern 13 furthermore includes a pattern of alternating (in the IR range) light and dark lines 24 extending transversely over the track 12. In the present case, such a pattern of light and dark lines 24 is situated at each end of the road segment. The attachment of a pattern of light and dark lines at a different location can also be expedient.

[0042] When the toy vehicle 1 drives over the track 12, according to the disclosure and according to an operating method according to the disclosure, an IR beam emitted by the IR emitter 10 strikes the orientation pattern 13, is reflected there, and is finally received by the IR receiver 11. The intensity of the received IR beam depends on whether the emitted IR beam strikes a light or a dark section of the IR-sensitive orientation pattern 13. When the toy vehicle 1 drives along the track 12, the IR receiver 11 receives alternately a weak and a strong reflected signal. When the pattern of triangular sections 23 is detected, the succession of weak and strong signals changes with a change in the lateral positioning of the toy vehicle 1 relative to the track 12. It can be calculated by a suitable evaluation algorithm to what extent the toy vehicle 1 is situated to the left or right on the track 12. The orientation of the vehicle longitudinal axis x (FIGS. 2, 3) relative to the longitudinal direction of the track 12 can moreover be determined.

[0043] Supplementarily, specific information can be encoded in the pattern of light and dark lines 24 and is identified via the IR sensor when it is driven over and then decoded, for example, in the control unit 5. For example, it is possible to encode in the pattern of light and dark lines 24 what type of a road segment it is (straight line, tight curve, or the like). When the vehicle enters such a road segment, the system identifies via the IR sensor the type of the road segment which then follows such that the further operating procedure can be prepared, for example by adapting the speed. Different information can of course also be encoded in the pattern of light and dark lines 24 such as, for example, the presence of a start and finish line. This information is detected and decoded in the same way such that corresponding events (time measurement, lap counting, et cetera) can be triggered.

[0044] In particular in the context of the toy vehicle system shown, the sensor 9 is a functional part of the control unit 5 (FIGS. 2, 3), wherein the control unit 5 is configured to derive the target value for the yaw rate w.sub.z from the control signals calculated by the sensor 9. On the one hand, the target values for the yaw rate .sub.z can be derived and determined in such a way that the toy vehicle 1 automatically follows the track 12. Alternatively or additionally, the control unit 5 can be configured to derive specific driving events, in particular braking, acceleration, and/or affecting the yaw rate .sub.z, from the sensor signals calculated by the sensor 9. For example, the vehicle can be decelerated when it reaches the edge of the track and accelerated when it reaches the center of the track. Moreover, evasive or skidding movements can be simulated by modifying the yaw rate .sub.z.

[0045] In particular, derivation of the target value for the yaw rate .sub.z takes place in the control unit depending both on the calculated sensor signals of the sensor 9 and on the control signals generated by the remote control 8 and received by the receiver 7. This enables, for example, a driving simulation in which the user can freely control the toy vehicle 1 along the track 12 if specific conditions are met. However, if the user steers the toy vehicle 1 too closely to the edge or into a specially marked zone, this is detected by the sensor 9. Predetermined driving events already mentioned above can subsequently be triggered which affect the control signals of the user. This effect can be superposed (modified steering or braking action). It can likewise be considered that the control signals generated by the user are completely overridden in order, for example, to force the toy vehicle to stop or to move toward the edge of the road. A multiplayer mode with or without corresponding driving events adapted thereto is of course also possible.

[0046] Overall, a realistic-looking small-format driving mode along a predetermined track 12 with a realistic appearance is thus possible. The degree of difficulty of the driving behavior of the toy vehicle 1 can be set virtually as desired and adapted to the ability of the user. All hybrid forms, with different weighting, between a fully autonomous mode in which the toy vehicle 1 automatically follows the track 12 and a freely controlled, electronically uninfluenced driving mode can thus be set.

[0047] Because the essential property of the track 12 resides in its orientation pattern 13, it can be produced cost-effectively from simple materials such as cardboard or the like. Virtually any desired tracks can be formed from standardized segments thereof and closed to form a circuit. The IR-sensitive orientation pattern 13 is optionally covered by an IR-permeable but visually opaque covering layer 14, as a result of which the optical appearance of an asphalt track with side and center stripes, a dirt road, or any other desired simulated driving surface can be produced. The orientation pattern 13 situated below it is covered by it and remains invisible to the human eye but can be reached by the IR sensor 9.

[0048] A conventional remote control known from vehicle model making can be used as the remote control 8. The remote control 8 is preferably, as depicted in FIG. 4, a smartphone with an app running on it which generates the control signals for the toy vehicle 1. The wireless connection between the remote control 8 and the toy vehicle 1 is here preferably effected via Bluetooth. However, a Wifi connection or a different form of wireless connection can also be expedient. The app running on the smartphone can be configured in a simple fashion as just a control app or in a complex fashion with a sophisticated driving simulation. There is in particular the possibility of a multiplayer mode via an Internet connection. In this case, multiple players, even physically separated from one another, can build the same track from track segments and drive vehicles thereon at the same time and against one another in competition mode without them having to physically meet. Collisions, overtaking maneuvers, or the like can thus be simulated with the above-described means.

[0049] A further aspect consists in the fact that the toy vehicle 1 can automatically or under the control of the user drive over the whole road once and thus detect it via the IR sensor 9. In this way, the route of the laid-out track 12 can be identified and fed into the simulation before the actual training or competition drive.

[0050] The disclosure is described above on the basis of an example in which the toy vehicle 1 is a replica car with at least two, in this case exactly two steerable wheels 2 and with at least two, in this case exactly two non-steerable wheels 3. For the sake of simplicity, the yaw rate sensor 6 is illustrated here only as a single-axis yaw rate sensor for detecting the yaw rate .sub.z about the vertical axis z.

[0051] In an alternative embodiment of the disclosure, the toy vehicle 1 according to the illustration in FIGS. 5, 6 is a replica motorcycle with just one steerable wheel 2 and with just one non-steerable wheel 3. The wheel 2 which is steerably mounted on the chassis of the toy vehicle 1 with a changeable steering angle about a steering axis 27 is, in the same way as in the embodiment according to FIGS. 1 to 4, subject to the action of the steering drive 4, which includes the regulation described above in detail of the yaw rate .sub.z about the vertical axis z via the steering drive 4, the control unit 5, and the yaw rate sensor 6.

[0052] The yaw rate sensor 6 is here configured and able, as is the control unit 5, to detect, in addition to the yaw rate .sub.z about the vertical axis z, also the yaw rate .sub.x about the longitudinal axis x (FIG. 6) and the yaw rate .sub.y about the transverse axis y. This is the standard form found today of commercially available yaw rate sensors 6 which is preferably used not only here in a replica motorcycle but in practice also in a replica car according to FIGS. 1 to 4.

[0053] It can be seen in the front view according to FIG. 5 that, when the toy vehicle 1 in the form of a replica motorcycle drives in a curve, its vertical axis z is inclined relative to a surface normal z of the track 12 to be driven on by an angle of inclination . Together with the toy vehicle 1, its yaw rate sensor 6 is also inclined by this angle of inclination . Driving in a curve on the track 12 results in a yaw rate .sub.z of the toy vehicle about the surface normal z, that is, about an axis which is perpendicular to the surface of the track 12. The yaw rate sensor inclined by the angle of inclination detects a yaw rate .sub.z, resulting therefrom, about the vertical axis z and a yaw rate w.sub.y, likewise resulting therefrom, about the transverse axis y, but the yaw rate .sub.y about the surface normal z is readily derived therefrom such that regulated driving in a curve or in a straight line as in the embodiment according to FIGS. 1 to 4 is possible and is performed during operation. When driving in a straight line, the angle of inclination equals zero, according to which the vertical axis z is thus perpendicular and parallel to the surface normal z.

[0054] It can also be seen from looking at FIGS. 5, 6 together that the toy vehicle 1 configured as a replica motorcycle has a controlled support device 25 for specifying the above-described angle of inclination . In the embodiment shown, the support device is a pair of arms attached to the underside of the toy vehicle 1 and projecting laterally. At least one of these arms, in this case both arms, stand on the track 12 with their end regions during operation. For this purpose, small support rollers which roll on the track 12 are fastened at their ends. Instead of the support rollers, skids or the like can also be expedient. The arms of the support device 25 are pivotably mounted on the chassis of the toy vehicle 1 with a changeable pivoting angle , wherein the associated pivot axis runs parallel to the longitudinal axis x of the toy vehicle 1. A pivoting drive 26 for setting the pivoting angle acts on the arms of the support device 25. It can also be expedient that each arm has its own pivoting drive 26. The pivoting angle set in each case specifies the angle of inclination of the vertical axis z of the toy vehicle 1 relative to the surface normal z.

[0055] The pivoting drive 26 can be a servo with a potentiometer of conventional form. In the embodiment shown, the pivoting drive 26 is part of the steering unit already described above, wherein the steering unit has no sensor for calculating the pivoting angle . Also in conjunction with the setting of the angle of inclination , the steering unit thus also dispenses with a potentiometer of a servo or the like. Rather, in a similar fashion to the steering of the wheel 2 about its steering axis 27, the pivoting drive 26, the control unit 5, and yaw rate sensor 6 together form a regulating loop for setting the yaw rate .sub.x to a predetermined target value: if therefore the toy vehicle transitions, for example, from driving in a straight line into driving in a curve, then it must for a realistic appearance be moved from a perpendicular position into an inclined position with an angle of inclination 0. For this purpose, in the method according to the disclosure, a corresponding target value of the yaw rate .sub.x is generated, following which the support device 25 is moved toward a modified pivoting angle . Subsequently, the angle of inclination with a yaw rate .sub.x is modified until the angle of inclination has reached its desired value. As soon as this has happened, the target value of the yaw rate .sub.x is correspondingly resumed and the achieved desired angle of inclination is maintained. Adaptations of different angles of inclination function in the same way, this also being true for orienting the toy vehicle after it has finished driving in a curve.

[0056] It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.