GB2472786A

GB2472786A - Steering arrangement for toy vehicle

Info

Publication number: GB2472786A
Application number: GB0914337A
Authority: GB
Inventors: Phillip Matthew Jermyn
Original assignee: Alien Technology Ltd
Current assignee: Alien Technology Ltd
Priority date: 2009-08-17
Filing date: 2009-08-17
Publication date: 2011-02-23
Also published as: GB0914337D0

Abstract

A toy vehicle apparatus includes a body portion 4 with two or more rotatable wheels 6,8,10,12 associated with the same for allowing the apparatus to move across a surface in use. The orientation of at least one of the wheels is substantially fixed and directional control of the apparatus is achieved by independently controlling the speed of drive means 16,18 associated with the at least one substantially fixed wheel. Thus, both the functions of movement and steering of the toy vehicle are controlled by varying the speed of the motors 16 and 18. Further disclosed is a toy vehicle apparatus having a gyro sensing means for providing feedback for controlling steering of the vehicle in use. Also disclosed is a toy vehicle apparatus wherein electrical pulses are provided to a drive means.

Description

To Vehicle Apparatus and Method of Use Thereof This invention relates to toy vehicle apparatus and a method of use thereof.

Although the following description refers almost exclusively to toy vehicle apparatus in the form of a toy car, it will be appreciated by persons skilled in the art that the toy vehicle of the present invention could be provided in any suitable form, such as a lorry, tractor, plane, train and/or the like.

It is known to provide a toy car that can be driven by electrical means and which can be controlled remotely using a remote control handset, or directly using one or more controls provided on the toy car. The toy car typically includes a housing having the external appearance of a car chassis with four wheels; one wheel located at each corner of the housing. The front and rear wheels are typically rotatable about a horizontal axis to allow movement of the toy car across a surface. In addition, the front and/or rear wheels may be pivotable or can be orientated in different directions to allow steering or turning of the toy car in use. The requirement for such a steering mechanism increases the complexity of the toy car and typically requires the car to be of a reasonable size in order to provide sufficient space for the mechanical components forming the steering mechanism.

Conventional toy cars that are electrically powered normally include a D.C (Direct Current) motor. The standard method of controlling the speed of a D.C motor is to supply the same with electrical pulses at a particular frequency, different speeds being achieved at the motor by varying the proportion of time (time duration) the power or voltage to the motor is in an "on" condition for. The frequency of the electrical pulses in time is typically sufficiently high to allow the motor's inductance to maintain a smooth electrical current. This allows the motor to behave as if powered via a variable voltage D.C. The method is known as Pulse Width Modulation (PWM) and is illustrated in figure 1. The figure shows the voltage of the electrical pulses on the vertical axis against the duration of the pulses in time on the horizontal axis when the motor is being operated at a) low speed; b) high speed and c) 100% or maximum speed. It can be seen that the frequency of the electrical pulses in time is the same in order to achieve both low and high speeds of the motor.

1-Jowever, the time duration of the electrical pulses is much shorter when the motor is to be run at low speeds a), compared to when the motor is to be run at higher speeds b). A constant electrical signal or voltage is provided when the motor is to be run at maximum speed c).

A problem associated \vith use of a PWM method to control a D.C motor in a toy car is that the motor torque is low at low speed settings. As such, the speed has to be set high in order to provide sufficient torque to get the car to start moving. Once the static friction has been overcome, this tends to cause the car to lurch off at high speed with poor control.

A further problem associated with toy cars is that due to their relative small size they tend to be directionally unstable and often spin out of control. There are several reasons for this: a) the factors that promote stability of the vehicle, such as vehicle moment of inertia, and friction between the wheels and the surface on which the car is to travel, fall at high orders of proportionality (i.e. square law, cubic law or greater) with reducing scale; b) the factors that tend to disturb stability of the vehicle do not fall as quickly as the factors that promote stability, and some may actually increase (i.e. surface irregularities over which the vehicle will move in relation to wheel size); c) even though the car is small, it is not desirable to reduce the running speed of the car proportionally. Thus, the relative speed of the car tends to increase with reduced scale of the car; d) for simplicity, a small toy car tends to be constructed without suspension means being provided; e) the short wheel base of the vehicle required for optimum working of the steering mechanism does not promote stability.

it is therefore an aim of the present invention to provide toy vehicle apparatus which overcomes one or more, and preferably all, the abovementioned problems.

It is an aim of the present invention to provide a method of using toy vehicle apparatus.

According to a first aspect of the present invention there is provided toy vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels associated with the same for allowing the apparatus to move across a surface in use, and wherein the orientation of at least one of said wheels is substantially fixed and directional control of said apparatus is achieved by independently controlling the speed of drive means associated with said at least one substantially fixed wheel.

Thus, by controlling the speed of the drive means associated with the fixed wheel, this alters the speed of rotation of said fixed wheel. The drive means to the at least one fixed wheel is typically independent of any other drive means provided in the vehicle, thereby allowing independent control of said at least one fixed wheel. In one embodiment one or more other fixed wheels on the vehicle will have no drive means associated with the same.

In one embodiment separate drive means are associated with two fixed wheels in said vehicle to allow independent speed control of said two fixed wheels. For example, in order to move the vehicle in a forwards or backwards direction, the two drive means can be driven substantially in unison and at the same speed. In order to steer the vehicle and make the vehicle turn in a direction different to the direction of the fixed orientation of the wheels, the speed of one of the drive means is adjusted compared to the speed of the other drive means. This results in the wheels rotating at different rates, causing the vehicle to turn.

in a preferred embodiment the vehicle comprises at least four wheels. Preferably the orientation of the four wheels is substantially fixed and further preferably at least one wheel is provided at or adjacent each corner of the vehicle. For example, the vehicle could include at least two front wheels and at least two rear wheels.

Preferably separate and independently controlled drive means are associated with each of the two wheels at the rear of the vehicle or each of the two wheels at the front of the vehicle.

Preferably the drive means includes a motor. Thus, in one example, a motor is associated with a wheel to independently drive the speed of said wheel.

The vehicle is typically provided with power means for providing power to said drive means. The power means can include battery power, rechargeable battery power, mains electrical power and/or the like.

Control means can be provided on the toy vehicle to allow control of the same, such as for example to move the vehicle between operational and/or non operational conditions, to control the power to the drive means, to control the speed of the drive means and/or the like.

In one embodiment the toy vehicle can be controlled remotely using remote control means in addition to or as an alternative to any control means on the vehicle. The remote control means can communicate with the toy vehicle via any suitable means, such as radio waves, infra-red, micro-waves and/or the like.

The toy vehicle can be provided in any suitable form, such as a motorbike, car, lorry, tractor, train, truck, aeroplane and/or the like.

In one embodiment the one or more drive means or motors are provided co-axially and preferably along a substantially horizontal axis of the vehicle. For example, the motors could be provided co-axially between the two rear or front wheels of the vehicle (i.e. the rotational part of the motor is provided co-axially of the same rotational part of the other motor).

in one embodiment the one or more fixed wheels include gear means. In this embodiment the drive means or motors are provided substantially parallel to each other (for example, one motor could be provided in front of the other motor between the front and rear or longitudinal axis of the vehicle). The size or width of the body portion and thus the toy vehicle can be further reduced compared to the embodiment in which the motors or drive means are arranged co-axially.

Preferably the body portion is provided with a chassis or housing which provides a realistic external appearance for the vehicle. The electronics for the toy vehicle can be provided on the body portion and preferably within the chassis or housing of the vehicle to hide the same from view.

According to a second aspect of the present invention there is provided toy vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels for allowing the apparatus to move across a surface in use, drive means being provided to control the movement and/or speed of the vehicle and power means provided to power the drive means, and wherein the power to the drive means is arranged to provide electrical pulses of pre-determined, substantially constant time duration and the frequency of electrical pulses in time is

adjustable.

Thus, by providing electrical pulses to the drive means of substantially constant time duration but which can vary or be adjusted in frequency, this provides the drive means with sufficient energy for short periods of time to drive the drive means in short bursts and thus move the wheels of the vehicle in sufficiently short bursts that the vehicle can move with increasing speed and in a controlled manner compared to the

prior art.

Preferably the power or voltage supplied to the drive means is substantially constant in use in the "on" condition.

Control or adjustment means allows the frequency of the electrical pulses in time to the drive means to be varied.

Preferably the one or more motors or drive means include single stage gear reduction to improve energy efficiency. Further preferably the ratio of the single stage gear reduction is 3:1. This is in contrast to prior art toys that typically rely on multi-stage gear reduction.

Preferably the toy vehicle is a miniature toy vehicle \vith the length of the wheel base of the vehicle being less than 20mm and the width of the vehicle being less than 25mm.

According to a third aspect of the present invention there is provided toy vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels for allowing the apparatus to move across a surface in use, and wherein the apparatus includes gyro sensing means to provide feedback for controlling steering of the toy vehicle apparatus in use.

Use of gyro sensing means in the present invention significantly increases the stability of toy vehicle and prevents the same from spinning out of control during use. This allows the toy vehicle to be provided in smaller or miniature sizes compared to prior art toy vehicles.

Preferably the gyro sensing means measures yaw movements or the rate of yaw movements and provides a feedback signal for use with processing means associated with drive means for the v clii c 1 e.

Preferably the gyro sensing means provides a feedback signal to oppose one or more signals controlling the steering mechanism associated with the drive means.

Preferably the gyro sensing means uses Piezo or Silicon MEMS technology to produce an output signal proportional to the rotational speed of the car in the yaw axis.

It will be appreciated that any or any combination of the abovementioned features and/or aspects can be used to provide a toy vehicle of the present invention. In one embodiment the toy vehicle includes independently controlled drive means or motors for controlling the steering of the vehicle, adjustment means for adjusting the frequency of electrical pulses to the drive means or motors and/or gyro sensing means for providing a feedback signal for the steering control of the vehicle.

According to a yet further aspect of the present invention there is provided a method of using toy vehicle apparatus.

Embodiments of the present invention will now be described with reference to the accompanying figures, wherein: Figure 1 illustrates a conventional Pulse Width Modulation (P\XIM) method used in controlling the speed of a D.C Motor on a conventional toy car; Figure 2 is a simplified view of a toy car layout according to an embodiment of the present invention; Figure 3 illustrates the control method for varying the frequency of the electrical pulses used to drive the drive means for the toy car according to an embodiment of the present invention; Figure 4 is a simplified view of the control system for controlling a toy vehicle according to an embodiment of the present invention; and Figures 5a and 5b illustrate the base of a vehicle according to an embodiment of the present invention in which the motors are provided in a co-axial arrangement and a parallel arrangement respectively.

Referring firstly to figure 2, there is illustrated a toy car 2, said toy car 2 including a body portion or housing 4 \vith four wheels associated therewith for allowing the car to move across a surface in use; two front wheels 6, 8, and two rear wheels 10, 12.

Each wheel 6, 8, 10, 12 is rotatable about a substantially horizontal axis 14 but the orientation of the wheels is substantially the same and is fixed.

In accordance with one aspect of the present invention, drive means in the form of two motors 16, 18 are directly connected to means for independently driving wheels 10, 12 respectively.

Both the functions of movement and steering of the car 2 are controlled by varying the speed of motors 16, 18.

For example, in order to make the car 2 move in a forwards or backwards direction (i.e. in a substantially straight line in the same direction the wheels are orientated) motors 16, 18 are driven substantially at the same speed and in unison. In order to make the car 2 steer left or right, the speed of one motor 16, 18 is increased and the speed of the other motor 16, 18 is reduced, thereby resulting in the wheels 10, 12 rotating at different rates and causing the car to turn. The car 2 can be turned about a point even when the car is substantially stationary.

In accordance with a second aspect of the present invention, in order to provide the car 2 with greater stability and control of speed, means are provided to allow adjustment of the frequency of electrical pulses or throttle control supplied by power supply means to the motors 16, 18, as shown in figure 3. The voltage of the electrical pulses supplied to each motor is shown along the vertical axis and the duration in time of the electrical pulses is shown on the horizontal axis for operation of the motor at a) low speed, b) higher speed, and c) 100% speed or maximum speed. The frequency of the electrical pulses is increased in order to achieve a higher speed of the motor and thus greater rotational speed of the wheels 10, 12. The frequency of the electrical pulses is reduced in order to achieve a lower speed of the motor and thus reduced rotational speed of the wheels 10, 12. Each electrical pulse effectively acts like a short burst of power or maximum speed (and thus torque), rather than contributing to an overall average supply voltage. By delivering pulses at low frequency the car can be made to move along in small notches and can speed up smoothly and in a controlled manner. This system is so effective that it allows the motors 16, 18 to drive the rear wheels 10, 12 directly, without any gearing mechanism being provided. It allows both the linear speed and steering of the car 2 to have fine control with the minimum of mechanical components, thereby allowing a very small or miniature toy car to be constructed.

In a preferred embodiment the pulses are approximately held for 5miliseconds in time. The motors typically use a single stage gear reduction with a ratio of 3:1.

Referring to figure 4, there is illustrated a simplified view of a control system used for controlling the toy vehicle in one embodiment of the present invention. Processing means for the system receives an input 20 from remote control means for providing a steering command to the motors of the car. A yaw rate gyro sensor 22 provides a further input signal to stabilise the vehicle and output signals 24, 26 are sent to the left rear wheel motor 16 and the right rear wheel motor 18 respectively.

in addition, an input is sent to the processing means from a power or throttle command 28 which is added to the output signals 24, 26 sent to control the left and rear wheel motors 16, 18. The input and output signals can be positive or negative since the controls are bi-directional.

Use of the gyro sensor allows the car to be actively held on a user selected course of travel, allowing the vehicle to accelerate rapidly in a substantially straight line without spinning out of control. The system also allows the vehicle to make aggressive turns at high speed, involving outward sliding or "drift" without loss of control.

Figure 5a shows an arrangement of the motors 16, 18 when used to independently drive the rear wheels 10, 12 of the car in a non-geared set up. The motors 16, 18 are co-axial and arranged along a substantially horizontal axis parallel and co-axial with the rotational axis of the wheels.

Figure 5b shows an arrangement of the motors 16, 18 when used to independently drive the rear wheels 10, 12 of the car in a geared set up. The motors 16, 18 are parallel and arranged one in front of the other along the longitudinal axis of the vehicle.

The motors 16, 18 each drive a first gear wheel 30 which is then used to drive at least one further gear wheel 32.

It can be seen that each aspect of the invention alone or in combination provide improved stability and control of the steering and throttle for the toy vehicle. This allows the toy vehicle of the present invention to be provided in smaller dimensions that a conventional toy vehicle without reducing the stability of the vehicle.

Claims

Claims 1. Toy vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels associated with the same for allowing the apparatus to move across a surface in use, and wherein the orientation of at least one of said wheels is substantially fixed and directional control of said apparatus is achieved by independently controlling the speed of drive means associated with said at least one substantially fixed wheel.
2. Apparatus according to claim I wherein one or more other substantially fixed wheels on the vehicle have no drive means associated with the same.
3. Apparatus according to claim I wherein separate drive means are associated with two substantially fixed wheels in the vehicle to allow independent speed control of said two fixed wheels.
4. Apparatus according to claim I wherein the vehicle comprises at least four wheels; at least two wheels provided at the front of the vehicle and at least two wheels provided at the rear of the vehicle, and either the two front wheels or the two rear wheels are each provided with separate and independently controlled drive means.
5. Apparatus according to claim I wherein the drive means includes a motor and the motor is independently associated with said at least one substantially fixed wheel to independently control the speed of said wheel.
6. Apparatus according to claim 1 wherein the vehicle is provided with power means to power the drive means.
7. Apparatus according to claim 6 wherein the power means include any or any combination of battery power, rechargeable battery power or a mains electrical supply.
8. Apparatus according to claim I wherein control means are provided on the toy vehicle and/or the toy vehicle is controlled remotely via remote control means.
9. Apparatus according to claim 1 wherein the toy vehicle is in the form of a motorbike, car, lorry, tractor, truck, plane or train.
10. Apparatus according to claim 3 wherein the drive means are provided co-axially between front or rear wheels of the vehicle.
11. Apparatus according to claim 3 wherein the one or more substantially fixed wheels include gear means and the drive means are provided substantially parallel to each other.
12. Apparatus according to claim I wherein the body portion is provided with a chassis or housing giving a realistic appearance of a vehicle.
13. Apparatus according to claim 7 wherein the power to drive means is arranged to allow electrical pulses of pre-determined, constant time duration and the frequency of the electrical pulses in time is adjustable.
14. Apparatus according to claim I wherein the drive means or one or more motors includes single stage gear reduction.
15. Apparatus according to claim 14 wherein the single stage gear reduction is 3:1.
16. Apparatus according to claim I wherein the toy vehicle is a miniature toy vehicle with the length of the wheel base of the vehicle being less than 20mm and the width of the vehicle being less than 25mm.
17. Apparatus according to claim 1 wherein gyro sensing means are provided on the apparatus to provide feedback for controlling steering of the apparatus in use.
18. Apparatus according to claim 17 wherein the gyro sensing means measures yaw movements or the rate of yaw movements and provides a feedback signal for use with processing means associated with said drive means.
19. Apparatus according to claim 17 wherein the gyro sensing means uses Piezo or Silicon MEMs technology to produce an output signal proportional to the rotational speed of the car in the yaw axis.
20. 10)7 vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels for allowing the apparatus to move across a surface in use, and wherein the apparatus includes gryo sensing means for providing feedback for controlling steering of the toy vehicle apparatus in use.
21. Toy vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels for allowing the apparatus to move across a surface in use, drive means being provided to control the movement and/or speed of the vehicle and power means to power the drive means, and \vhereifl the power to the drive means is arranged to allow electrical pulses of pre-determined and substantially constant time duration to be provided to the drive means and the frequency of electrical pulses in time is adjustable.
22. A method of using toy vehicle apparatus, said apparatus including a body portion with two or more rotatable wheels associated with the same for allowing the apparatus to move across a surface in use, the orientation of at least one of said wheels being substantially fixed and wherein the method includes the step of independently controlling the speed of drive means associated with said at least one substantially fixed wheel to provide directional control to the vehicle.