Patent Grant
10232277
Toy or model vehicles are widely used in numerous variations. For the operation, the user actuates a remote-control transmitter. The control output signals thereof are as a general rule transmitted over a radio path to a receiver of the toy vehicle and are converted there into a corresponding driving movement. In this case, the significant control functions consist of a right-left control and the setting of a setpoint vehicle speed including acceleration and deceleration.
The toy vehicle itself is modeled in the basic technical features thereof on the usual configuration of a motor vehicle: in the general case, the front and rear axles are provided with a total of four wheels, wherein one of the axles, in most cases the front axle, is steerable. At least one of the wheels is driven via a drive motor, via which the toy vehicle can be accelerated. Conversely, a brake mechanism is also provided for deceleration. In the case of an electric drive, the acceleration and the deceleration can be exerted with the same electric motor in motor mode on the one hand and in generator mode on the other hand. In any case, cornering, accelerations and/or decelerations can result in at least some of the wheels transmitting frictional forces to the ground in the longitudinal and/or lateral direction. So that the toy vehicle does not skid on the ground, the wheels include tires made of rubber, elastomeric plastics or similar materials.
In practical operation, it has been shown that such remote-control toy vehicles are difficult to control. Even at only low drive power, speeds and above all accelerations can be achieved that hardly relate to the available space conditions for example in a living room. Unless an actual designated model racing track is available, staging a vehicle race is only possible with difficulty. Collisions and breakages can hardly be avoided. Moreover, the achievable speeds and accelerations are not in proportion to the small size of the toy vehicle, even from the visual appearance viewpoint, so there is a rather unrealistic driver impression when operating. Voluntary limiting of the acceleration and speed is indeed sometimes possible, but this restricts the driving dynamics in such a way that the attraction of operating a toy vehicle that is limited in this way is lost.
It is an object of the invention to provide a toy vehicle system so that a realistic impression of driving under drift conditions can be imparted, even under tight spatial conditions.
This object can, for example, be achieved by a toy vehicle system including: a toy vehicle defining a longitudinal vehicle axis; a remote control transmitter; the toy vehicle having a drive including at least a first drive motor and a second drive motor; the toy vehicle further having at least a first roller element and a second roller element configured to transfer friction forces and drive torque to a ground; the first roller element defining a first rotational axis; the second roller element defining a second rotational axis; the first and second roller elements being configured to be independently driven about respective ones of the first rotational axis and the second rotational axis; at least one steering device configured to adjust an orientation direction of the first rotational axis and the second rotational axis relative to the longitudinal vehicle axis; and, a control unit configured to receive control input signals from the remote control transmitter and to generate control output signals configured to act on the first drive motor, the second drive motor and the at least one steering device.
It is a further object of the invention to provide a generic toy vehicle system such that a dynamically acting and yet controllable driving mode is possible, even under tight spatial conditions.
This object can, for example, be achieved by a toy vehicle system including: a toy vehicle having a drive with roller elements configured to transfer frictional forces to a ground and a steering device; a remote control transmitter; a control unit configured to receive control input signals from the remote control transmitter and to generate control output signals configured to act on the drive and on the steering device; the control unit being configured to call up a virtual adhesive force limit Fm as well as a virtual frictional force Fg between the toy vehicle and the ground; the virtual adhesive force limit Fm being smaller than a corresponding actually transferable maximum frictional force between the first roller element and the second roller element and the ground; the virtual frictional force Fg≤the virtual adhesive force limit Fm; the control unit being configured for a computational driving simulation with incorporation of the control input signals of the remote control transmitter such that: the control unit computationally determines an uncorrected operational frictional force Fb acting between the toy vehicle and the ground, and compares the uncorrected operational frictional force to the virtual adhesive force limit; wherein, in a normal mode, in which the computationally determined uncorrected operational frictional force Fb is less than the virtual adhesive force limit Fm, a driving behavior of the toy vehicle is computationally simulated under local action of a virtual operating force Fv at the level of the uncorrected operational friction force Fb; wherein, in a skidding mode, in which the computationally determined uncorrected operational frictional force Fb is greater than the virtual adhesive force limit Fm, the driving behavior of the toy vehicle is simulated under local action of a virtual operating force at the level of the virtual frictional force Fg; and, the control unit is further configured to, from the computational driving simulation, generate control signals and have them act on the drive with the first roller element and the second roller element as well as the at least one steering device such that the toy vehicle performs a driving motion according to the computational driving simulation under action of the virtual operating force Fv.
It is a further object of the invention to specify an operating method for a toy vehicle system, via which a model vehicle can be operated dynamically and yet controllably, even under tight spatial conditions.
This object can, for example, be achieved by a method of operating a toy vehicle system. The toy vehicle system includes a toy vehicle having a drive with roller elements configured to transfer frictional forces to a ground and a steering device, a remote control transmitter, a control unit configured to receive control input signals from the remote control transmitter and to generate control output signals configured to act on the drive and on the steering device, the control unit being configured to call up a virtual adhesive force limit Fm as well as a virtual frictional force Fg between the toy vehicle and the ground, the virtual adhesive force limit Fm being smaller than a corresponding actually transferable maximum frictional force between the first roller element and the second roller element and the ground, the virtual frictional force Fg≤the virtual adhesive force limit Fm; and, the control unit being configured for a computational driving simulation with incorporation of the control input signals of the remote control transmitter such that the method comprises the steps of: computationally determining an uncorrected operational frictional force Fb acting between the toy vehicle and the ground via the control unit; comparing the uncorrected operational frictional force to the virtual adhesive force limit; computationally simulating, in a normal mode wherein the computationally determined uncorrected operational frictional force Fb is less than the virtual adhesive force limit Fm, a driving behavior of the toy vehicle under local action of a virtual operating force Fv at the level of the uncorrected operational friction force Fb; simulating, in a skidding mode wherein the computationally determined uncorrected operational frictional force Fb is greater than the virtual adhesive force limit Fm, a driving behavior of the toy vehicle under local action of a virtual operating force at the level of the virtual frictional force Fg; and, generating control signals from the computational driving simulation via the control unit and having them act on the drive with the first roller element and the second roller element as well as the at least one steering device such that the toy vehicle performs a driving motion according to the computational driving simulation under action of the virtual operating force Fv.
The invention is firstly based on the knowledge that a toy vehicle can be significantly smaller than a motor vehicle for carrying people, but that certain physical parameters do not follow such a reduction. In particular, the latter concerns two parameters of the physics of driving, namely the acceleration due to gravity g and the coefficient of friction p. The acceleration due to gravity g can be assumed to be constant. The coefficient of friction acting between the wheels and the ground varies from vehicle to vehicle, but essentially lies within the same order of magnitude. The result of this is that the horizontal accelerations (longitudinal acceleration, deceleration, centripetal acceleration when cornering) achievable with different vehicles are at least approximately the same, and this is completely independent of the actual size of the vehicle.
The invention is further based on the knowledge that with vehicles becoming smaller the available motor power and/or brake power relative to size of vehicle rises out of proportion. This means that for toy vehicles of the usual size the physics of driving are determined less by the drive power and/or brake power, but rather by the available frictional force between the wheels and the ground. Under these circumstances, with a small toy vehicle, using the adhesion limit, horizontal accelerations can thus be achieved that are of the same order of magnitude as for a large vehicle. In the case for example of a toy vehicle reduced to a scale of 1:10, braking decelerations can be achieved that are 10 times those of the original vehicle when scaled to the size of the model vehicle. Logically, the same also applies to centripetal accelerations when cornering, so that the actual physics of driving acting on the toy vehicle do not experience a scale reduction as for the vehicle itself. As a result, this means that certain operating state limits, at which adhesion is exceeded and the toy vehicle starts to skid, only occur at excessive accelerations and excessive cornering speeds. However, it is just the operating state limits that form the appeal of a toy vehicle system.
Based on this, it is an essential core idea of the invention that it is not the excessive but actually transferable maximum frictional force that is reduced, but a suitable reduced virtual frictional adhesion force limit is specified, and that two different operating states can be simulated computationally based on the reduced virtual frictional adhesion force limit: In a normal mode, in which the computationally determined but uncorrected operating frictional force is less than the virtual frictional adhesion force limit, the driving behavior of the toy vehicle is computationally simulated under the local effect of a virtual operating frictional force at the level of the uncorrected operating frictional force. In other words, here the physics of driving with wheels adhering to the ground are represented computationally. Alternatively, in a skidding mode, in which the computationally determined uncorrected operating frictional force is greater than the frictional adhesion force limit, the driving behavior of the toy vehicle is simulated under the local action of a virtual operating frictional force, thus in this case a corrected operating frictional force, at the level of the virtual sliding frictional force. In other words, in this case the physics of driving of the skidding vehicle are represented computationally. As a result, the toy vehicle now no longer immediately and directly follows the control inputs of the driver at the remote-control transmitter, but the control output signals produced by the computational driving simulation for steering, drive power, brakes and/or similar. Depending on the simulation results, these are the vehicle movements in the adhering or skidding state. By suitable selection or adjustment of the virtual frictional adhesion force limit to the size of the vehicle, driving dynamics are set up with which not only the physical dimensions of the vehicle, but also the parameters that significantly influence the physics of driving experience a corresponding reduction. The toy vehicle includes a control unit, a drive with roller elements for transmitting frictional forces to the ground and a steering mechanism. The control unit is configured to carry out the computational driving simulation that was outlined above and generates therefrom control output signals and causes the signals to act on the drive with the roller elements and on the steering mechanism such that the toy vehicle carries out a vehicle movement according to the computational driving simulation under the action of the virtual operating frictional force. Logically, the same applies to the corresponding operating method carried out in the manner described above. Despite a reduction, precise modelling of the driving behavior in the normal mode and in the skidding mode and of the transition region between them is possible, because the actual driving behavior of the toy vehicle is always caused via the roller elements thereof, even in the skidding mode under the conditions of adhesion, and only the visual impression of skidding is imparted. However, the adhesion that is actually always present between the roller elements and the ground enables a precise and controlled movement process.
With a configuration according to an embodiment of the invention, the driver can carry out challenging and realistic driving tasks. The virtual frictional adhesion force limit, which occurs instead of the actually transferable maximum frictional force, contributes not only to a more realistic overall impression of the driving behavior, but considerably reduces the necessary speeds or accelerations for the boundary region between adhesion and skidding. The space necessary for realistically acting driving maneuvers can be reduced to a minimum. Complete vehicle races including drift bends and similar can be staged on the size of a desktop, whereas in doing so the visual impression of high speeds and accelerations is given. However, the actual speeds and accelerations are so low that the driver retains sufficient control.
The above conditions are examples for the case described that a reduction in scale of an original vehicle to a certain size of the toy vehicle has occurred, while at the same time the virtual frictional adhesion force limit has been reduced to a corresponding extent compared to the actually available maximum frictional adhesion force limit, so that the achievable accelerations are reduced at least approximately to the same scale. Logically, the same can of course also apply to limiting the maximum achievable speeds. In fact, however, no scaled relationship between the size of the toy vehicle and the virtual frictional adhesion force limit is necessary within the scope of the invention. First of all, it depends on the virtual frictional adhesion force limit being significantly reduced compared to the actual available frictional adhesion force limit in general, in order to simulate driving in the boundary region between adhesive friction and sliding friction under the circumstances of tight space conditions for small accelerations and cornering speeds. Moreover, it can also be advantageous to make the virtual frictional adhesion force limit variable. This allows driving on different ground with more or less slippery sections to be simulated.
In an advantageous embodiment of the invention, an acceleration in the direction of the longitudinal axis of the vehicle is specified, and a frictional force in the direction of the longitudinal axis of the vehicle is derived therefrom. If the frictional force exceeds the virtual frictional adhesion force limit, the acceleration in the direction of the longitudinal axis of the vehicle is reduced to an acceleration limit that corresponds to the virtual sliding frictional force. In this case, acceleration means any acceleration in the direction of the longitudinal axis of the vehicle, which thus besides a forward-directed increase in the speed also includes a braked deceleration corresponding to a rearward-directed acceleration. In any case, in this way either a forward-directed acceleration with rotating wheels or a braking deceleration with locked wheels is simulated and as a result realistic driving behavior is produced.
Alternatively or additionally, within the scope of the invention it is provided that when driving along a bend with a local radius, an acceleration of the toy vehicle in the direction of the local radius is derived and a frictional force transverse to the direction of the longitudinal axis of the vehicle is derived therefrom. If the frictional force acting transverse to the direction of the longitudinal axis of the vehicle exceeds the virtual frictional adhesion force limit, the control unit acts on the drive and/or on the steering mechanism of the toy vehicle such that the toy vehicle carries out a local component of motion transverse to the longitudinal axis of the vehicle.
The “local” component of motion means that it can indeed apply to the entire vehicle, but does not have to. It can be sufficient if only the front or the rear of the vehicle performs such a lateral component of motion to represent “breakaway”.
In the simplest case, the toy vehicle performs a motion that corresponds to sideways skidding without a change in the direction of the longitudinal axis. In an advantageous embodiment, the longitudinal axis of the vehicle is at a first angle to the local tangent of the bend being traversed in the normal mode, wherein the longitudinal axis of the vehicle, starting from the first angle, is then transitioned to a second angle to the local tangent of the bend being traversed in the simulated skidding mode. This allows the driving conditions to be reproduced realistically during understeer, but in particular also during oversteer, that is during so-called “drifting”.
For the implementation of the operating method described above, in physical means a suitably configured and programmed control unit on the one hand and a suitable physical configuration of the toy vehicle on the other hand are required. According to the latter aspect, the toy vehicle includes at least two drive motors and at least two roller elements for transferring drive torque to the ground, wherein the roller elements can be mutually independently driven rotationally about respective axes of rotation via the drive motors. The toy vehicle further includes at least one steering mechanism for adjusting directions of orientation of the axes of rotation relative to the longitudinal axis of the vehicle. The control unit configured in particular according to the provisos described above acts on the drive motors and the at least one steering mechanism. This enables the model vehicle to be moved in any direction that differs from the actual orientation of the longitudinal axis thereof. Conversely, the longitudinal axis of the vehicle can be brought into any relative orientation to the current direction of motion, so that on the one hand the normal mode and on the other hand the skidding mode can be implemented conspicuously and realistically without skidding of the roller elements on the surface actually occurring. Within the scope of the invention, it is however not absolutely necessary that the operating method described above or a correspondingly configured control unit is used. Rather, it can also be sufficient in a further aspect of the invention that the control unit is implemented simply and the simulation is wholly or partly omitted as long as the toy vehicle is otherwise physically implemented according to the above description. For example, by a signal output by the user (for example pressing a “drift” knob) or on meeting simple logical conditions (for example IF “vehicle speed≥x” AND “steering angle≥y” THEN . . . ) the toy vehicle can be moved such that the longitudinal axis of the vehicle is not parallel to the local direction of motion. In any case, this also gives the possibility of driving with a realistic impression of a drift motion, even during comparatively slow travel and/or under spatially tight conditions.
For the physical configuration mentioned above, different variants come under consideration. In one advantageous embodiment, two drive units are provided, each with a drive motor, each with a roller element and each with a dedicated steering mechanism, wherein a drive unit is disposed before or after the center of gravity of the toy vehicle in the direction of the longitudinal axis of the vehicle. As a result of the configuration, the vehicle rests on one of the drive units in the front region thereof and in the rear region thereof in each case. The front region and the rear region of the toy vehicle can be displaced mutually independently in more or less pronounced lateral movement, which enables almost any possibilities for the reproduction of the driving behavior in the boundary region between adhesive friction and sliding friction.
In an advantageous embodiment of the implementation mentioned above, the two steering mechanisms each include a bogie with a vertical steering axle and with an associated steering drive, wherein there is a respective drive motor associated with each bogie. At least each roller element is implemented in the form of a drive wheel and is supported with an associated first or second rotation axle on a respective bogie such that the first rotation axle and the second rotation axle are mutually independently displaceable via the two bogies. In particular, each of two drive wheels is disposed at an axial separation from the other on each of the two rotation axles. The arrangement is mechanically simple in configuration and reliable in operation. With a total of three and preferably four drive wheels, the model vehicle in most cases stands level and stable on the drive wheels. Additional supporting measures may be required in the case of strongly deflected drive units, and then only to a slight degree that does not adversely affect the driving behavior.
Alternatively, it can be advantageous that the roller elements are spherical, wherein first and second drive shafts are each disposed with an associated drive motor at a right angle to each other and engage the spherical surface of the roller elements by friction. In this case, the steering mechanism is formed by a coordination unit for a coordinated determination of revolution rates of the first and second drive shafts. The balls enable a direct and temporally delay-free change of orientation of the currently acting rotation axis thereof without a dedicated rotary drive being necessary for this. Transient changes of state can be represented without delay.
In an advantageous alternative, not two, but only exactly one drive unit is provided, which includes two drive motors, two roller elements in the form of wheels and a steering mechanism. The first roller element can be driven about the first rotation axle by the first drive motor. The second roller element is disposed at an axial distance from the first roller element and can be driven about the second rotation axle by the second drive motor, and indeed independently of the first drive motor. The first rotation axle and the second rotation axle can be commonly adjusted by the one steering mechanism. The center point between the two roller elements lies in the region of the center of gravity of the toy vehicle, so that the toy vehicle rests with most of the dead weight thereof on the roller elements of the one drive unit. The mechanically very simple but yet very effective implementation is based on the knowledge that the physics of driving acting in the plane of the ground to be traversed can be reduced to three motion variables, namely to two lateral components of motion in two mutually perpendicular directions and to a rotary motion about a vertical axis. This can also be actually mechanically implemented if the center point between the two roller elements lies in the region of the center of gravity of the toy vehicle. That is, most of the acting mass forces of the two roller elements or the two wheels are then taken up and converted into frictional force. Indeed, the two wheels are not sufficient to fully support the vehicle. Dummy wheels or other parts of the vehicle can however be used for positional stabilization with only small supporting loads without noticeably falsifying the driving conditions predetermined by the drive units because of the small supporting forces and frictional forces thereof.
No particular requirements are placed on the visual configuration of the toy vehicle. Any abstract but also correctly scaled shape can be selected. Nevertheless, it has been shown that the impression of “reduced” physics of driving turns out to be particularly realistic if the toy vehicle reproduces some essential features of people-carrying motor vehicles in the external appearance thereof. This includes above all the wheels of the original motor vehicle, which however cannot be used here for the same function as wheels. In a preferred embodiment, therefore at least one pair of dummy wheels is provided, wherein a pair of dummy wheels is advantageously configured to be steerable or freely deflectable. A “dummy wheel” in this case means an element that does have the visual appearance of a wheel, but does not carry out the function thereof. Such dummy wheels may indeed stand on the ground to be traversed and may also roll on the ground. However, because by far the greatest part of the weight force of the roller elements described further above is absorbed, they act as aids to support if necessary with significantly smaller contact forces, without setting up significant lateral frictional forces in this case. The dummy wheels thus do not determine the movement of the toy vehicle, which is the task of the roller elements mentioned above or the one or two drive units mentioned above. Also, any existing steering movement of the dummy wheels has no direct influence on the direction of travel of the toy vehicle. In other words, the dummy wheels can indeed be brought into a position typical of a vehicle and appear like normal wheels, but have in contrast thereto neither a driving nor a steering function. The small but existing contact forces of the dummy wheels in connection with a pivotal support and a caster can be used such that in the orientation thereof the dummy wheels follow the respective path, that is, they are freely deflectable. In most of the achievable driving states, this enhances the visual impression of a matching reproduction of the driving behavior. Of course, it is also possible to make the dummy wheels steerable and to actuate them actively in the steering movement thereof. If for example during oversteer or understeer the steering direction indicated by the driven dummy wheels does not agree with the actual vehicle movement, the visual impression of lateral skidding is enhanced. The dummy wheels can moreover be configured such that they visually conceal the actually acting drive units and in particular the roller elements thereof that are producing the vehicle movement. This also contributes to a realistic appearance of the vehicle movement.
From the outset, the basic principles of the computational driving simulation in the control unit and the generation of the control output signals derived therefrom have been described in abstract form, which applies to toy vehicles according to the invention of any configuration regardless of the details thereof. But if the toy vehicle is perceived, at least in respect of an original wheeled vehicle, that it includes at least one pair of dummy wheels, then the dummy wheels are also based on the driving simulation. More specifically, the computational driving simulation of the virtual frictional adhesion force limit, the virtual sliding frictional force, the uncorrected operating frictional force and the virtual operating frictional force between the dummy wheels and the ground is based on the assumption that the toy vehicle is rolling on wheels corresponding to the dummy wheels and would be driven by the dummy wheels. Based on the result of the computational driving simulation, there is then a physical vehicle movement that imparts the realistic impression as if the toy vehicle were driving or skidding on the dummy wheels thereof, whereas the actual vehicle movement is not brought about via the dummy wheels, but via the steering mechanism(s) and the drive unit(s), including the mentioned roller elements.
It can be advantageous that the control unit, in which the computational simulation of the physics of driving and the generation of the control output signals occur, is mounted in the toy vehicle or in the receiving unit thereof. However, the control unit is preferably disposed in the remote-control transmitter, so that only the control output signals processed in a manner according to the invention have to be transmitted by the remote-control transmitter to the receiver of the toy vehicle. No particular requirements are placed on the receiving unit of the toy vehicle, so that this can be made very small and also very inexpensive. A conventional remote-control transmitter comes under consideration that is augmented by a suitable control unit or that is reprogrammed in a suitable way. However, the assembly unit of a control unit and a remote-control transmitter is preferably formed by a programmed smartphone or by another mobile terminal such as a tablet or similar. As a general rule, the units have sufficient computational power and moreover suitable radio interfaces, so that suitable hardware is available to a wide public without additional investment. Only suitable programming is necessary.
The invention will now be described with reference to the drawings wherein:
The toy vehicle 1 is provided with a receiver 4 that receives control output signals of the remote-control transmitter 2. The toy vehicle 1 includes furthermore roller elements 6, 8 driving the toy vehicle 1 and a steering mechanism that are not shown here but that are described in detail further below, and that are actuated or operated via the receiver 4 according to the demands of the remote-control transmitter 2.
In the embodiment depicted, the receiver 4 receives the control output signals of the remote-control transmitter 2 via a radio path lying between them. In this case, this can for example be a Bluetooth connection, wherein however, other transmission protocols and transmission frequencies can also be considered. Other forms of signal transmission, for example via infrared or wired link, can also be implemented within the scope of the invention.
The toy vehicle 1 can include a more or less pronounced similarity to a people-carrying model vehicle, but is reduced in size compared thereto. No particular requirements are placed on the actual size of the toy vehicle 1. For the targeted operation under spatially tight space conditions, however, a maximum vehicle length from one meter down to a few centimeters is desirable and can also be implemented within the scope of the invention. In the case of a reduction in scale of a model vehicle, there are the usual reduction scales of 1:8, 1:10 and 1:12 to 1:24 or still smaller. Regardless of the actual or not yet implemented scale reproduction, advantageously at least one virtual front axle 23 and at least one virtual rear axle 24 are provided with the dummy wheels 21, 22 represented in
In operation, the toy vehicle 1 travels on ground 5 that is not represented in detail. In the case of uniform straight-ahead travel, no significant horizontal forces act between the toy vehicle 1 and the ground 5 in the plane of the ground 5. The latter changes once accelerations act on the toy vehicle 1 in the plane of the ground 5.
In
The control input signals produced by the user are not directly converted by the remote-control transmitter 2 into control output signals. Rather, a control unit 3 is provided that is integrated within the remote-control transmitter 2 here, and into which the control input signals of the remote-control transmitter 2 produced by the user or by the driver are supplied. Based on this, the control unit 3 generates control output signals modified according to the provisos described below, which then act on the drive and on the steering mechanism of the toy vehicle 1. A control unit 3 is used for this that is configured and programmed for a certain computational driving simulation that is described below.
The driving behavior influenced according to an aspect of the invention is based on a limitation of the maximum achievable operational acceleration ab via substitution for the uncorrected operating frictional force Fb of a corrected, virtual operating frictional force Fv, as schematically represented in the diagram according to
The principle in one aspect of the invention is clear in the simple example of the acceleration according to the overall view of
Provided that the driver only demands a moderate acceleration, in the case of which the uncorrected operating frictional force Fb is less than the virtual adhesive force limit Fm, the law of adhesion between the wheels and the ground 5 applies, which is referred to here as the normal mode. In the computational driving simulation, a virtual operating frictional force Fv is determined as one of the output variables. In the normal mode, the virtual operating frictional force Fv is set to be the same in magnitude and direction as the uncorrected operating frictional force Fb. The driving behavior of the toy vehicle 1 under the local action of the operating frictional force Fb is consequently computationally simulated in the control unit 3 according to an adhesive frictional force.
If, however, the driver demands too much “gas”, provided that the associated uncorrected operating frictional force Fb determined in this case in the computational driving simulation is greater than the previously specified virtual frictional adhesion force limit Fm, driving behavior is to be set up as for spinning wheels. This is referred to here as skidding mode, in which the virtual sliding frictional force Fg is acting. The virtual operating frictional force Fv is set in magnitude and direction the same as the virtual sliding frictional force Fg in this case and is used as the basis for the computational driving simulation. The toy vehicle 1 thus moves in the computational simulation as if the wheels were spinning under the action of the virtual sliding frictional force Fg.
In both cases of the normal mode or of the skidding mode, based on the respective computationally determined virtual operational frictional forces Fv, corresponding control output signals are generated such that the toy vehicle 1 performs a vehicle movement according to the computational driving simulation. In the case of the example according to
The simulation conditions for the simple case of a longitudinal acceleration are described above. In addition to this,
In
If the driver now preselects too high a speed in the bend and/or too small a local bend radius r, the computationally determined uncorrected operating frictional force Fb exceeds the virtual frictional adhesion force limit Fm (
Extending beyond a purely lateral vehicle displacement while maintaining the first angle α, in the simulated skidding mode the longitudinal axis of the vehicle 10 can be transferred starting from the first angle α thereof to a second angle β to the local tangent t to the bend 27 being traversed. Such a case is represented by way of example in
In connection with
An interesting aspect is for example that the virtual adhesive force limit Fm effectively acting as a changeover signal between the two operating modes does not have to be set to a certain magnitude. It can for example be different depending on the direction, therefore different limit values can be fixed for a forward acceleration, a braking maneuver and/or laterally acting centripetal accelerations. Moreover, the virtual adhesion force limits Fm can be varied during operation. This enables for example a progressive coefficient of friction-increasing wear or travelling on different ground with different adhesion properties to be simulated. The toy vehicle 1 can for example be provided with a detector that is not represented and that detects a section of the road to be considered as particularly slippery, and that as a result thereof causes a reduction of the otherwise already reduced virtual adhesive force limit Fm. In a further aspect of the invention, the changeover between the two operating modes does not have to be carried out based on the computational driving simulation described above. Rather, it can be sufficient to carry out the changeover for example automatically based on meeting simple logical conditions (IF-THEN conditions) or based on a signal specified by the user (operating a control function), wherein any combination of computational simulations, logic functions and/or user signals can be considered. In the extreme case, it can suffice within the scope of the invention to bring the longitudinal axis of the vehicle out of parallelism with the local direction of motion and as a result to impart the impression of drift motion, in particular when cornering.
Both drive units 13, 14 are each provided with a dedicated and mutually independently actuated steering mechanism, via which the directions of orientation of the axes of rotation 7, 9 about a respective vertical steering axis 16 can be adjusted relative to the longitudinal axis 10 of the vehicle. Details of the steering mechanism are revealed by the overall view of
Referring again to
In contrast to the roller elements 6, 8 responsible for the drive and also for the steering of the toy vehicle 1, the dummy wheels 21, 22 are dummies insofar as they do have the external appearance of wheels, but not the function thereof of tracking and/or of exerting drive. They are supported flexibly and/or upright on the chassis 25 relative to the roller elements 6, 8 such that either they do not contact the ground during operation, or if necessary only contact the ground 5 (
A special feature is that that the axial distance between the two roller elements 6 on the front rotation axis 7 and also the axial distance between the two roller elements 8 on the rear rotation axis 9 is optionally significantly less than the width of the chassis 25. As a result, it is achieved that the roller elements 6, 8 and the position of the axes of rotation 7, 9 thereof during operation are practically not visible or at most are visible to a restricted extent. The effect can also be increased by disposing each of the two drive units 13, 14 between a pair of dummy wheels 21, 22.
From the overall view of
Further above, it has already been noted that the virtual adhesive force limit Fm should be smaller than the actual maximum frictional force that can be transferred to the ground 5 via the drive elements 6, 8. A more accurate rendering of the requirement arises from the above descriptions: The virtual adhesive force limit Fm should be less than the frictional force between the drive elements 6, 8 and the ground 5 that is necessary for the reproduction thereof in the traction drive. This ensures that both the normal mode and the skidding mode can be represented via the drive elements 6, 8 in the pure adhesion mode.
As also in the case of the embodiment according to
Finally,
Details of the configuration according to
Unlike the embodiment according to
Unless expressly described otherwise, the embodiments according to
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2015 003 807 U | May 2015 | DE | national |
This application is a continuation application of international patent application PCT/EP2016/000882, filed May 27, 2016 designating the United States and claiming priority from German application 20 2015 003 807.7, filed May 26, 2015, and the entire content of both applications is incorporated herein by reference.
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| International Search Report dated Dec. 8, 2016 of international application PCT/EP2016/000882 on which this application is based. |
| Number | Date | Country | |
|---|---|---|---|
| 20180078868 A1 | Mar 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2016/000882 | May 2016 | US |
| Child | 15823391 | US |
