GB2366924A

GB2366924A - Electric carrier with a motor controlled by a relative positional mechanism

Info

Publication number: GB2366924A
Application number: GB0022354A
Authority: GB
Inventors: Gordon Liao
Original assignee: Unique Product and Design Co Ltd
Current assignee: Unique Product and Design Co Ltd
Priority date: 2000-09-13
Filing date: 2000-09-13
Publication date: 2002-03-20
Anticipated expiration: 2020-09-13
Also published as: GB2366924B; GB0022354D0; DE10047868A1

Abstract

An electric carrier 20 with a motor controlled by a relative positional mechanism includes an operator, such as a vehicle 10 or a person, a sensor 41 controlled by the operator and having a position reference member 40 driven by and moving together with the operator and a sensing body 41 producing a signal at any movement of the position reference member, a spring connected to the position reference member and distorted by the operator's driving so that the position reference member may return to its position and transmit force to an electric carrier to be mentioned below, a controller operated by a signal coming from the sensing body, a motor driven by the controller and accordingly having the functions of increasing and decreasing speed and clockwise and counter-clockwise rotation, and the electric carrier moved by the motor and with the operator synchronously. When the operator changes its position relative to the electric carrier, the sensor sends a signal to the controller, which then controls the electric carrier to change its speed to the same speed as that of the operator. The sensor may be a carbon brush (Figs 7-16), a magnetic sensor or a light or photo sensor providing an A to D converter output. Uses include an electric golf cart (Figs 5 and 6), wheelchair (Figs 23-25) and bicycle (Figs 21 and 22).

Description

<Desc/Clms Page number 1> ELECTRIC CARRIER WITH A MOTOR CONTROLLED BY A RELATIVE POSITIONAL MECHANISM BACKGROUND OF THE INVENTION This invention relates to an electric carrier with a motor controlled by a relative positional mechanism, particularly to one ergonomically conforming to human driving capacity, with the speed of the electric carrier being controlled by changing the relative position of an operator (such as a human person) and the carrier being controlled, such that the speed of the electric carrier may be altered in accordance with the speed of the operator. The electric carrier is moved by the motor, and there is a spring between the operator and the electric carrier, transmitting the force of the operator to the electric carrier. The coefficient or force constant of the spring is chosen in such a way so that the operator can control the electric carrier with a proper or no force. This electric carrier can be widely used in various industries.

Generally speaking, conventional electric carriers with a motor controlled by a relative positional mechanism nowadays have two ways of controlling the driving, an open route and a closed route.

The open route control, as shown in a block diagram of a flow chart in Fig. 1, has a controller for driving a motor, which directly moves an electric carrier. This kind of controlling mechanism is simple and of low cost, but is of limited value. For example, if the electric carrier is a car running on land, the car can run very smoothly on a flat road, with the speed controlled by a controller coping with the car. If, however, the car runs on an up or down slope, the motor cannot meet the demand of the necessary speed, limited by the slope condition. Thus, the open route control mode is only suitable to an environment of little change or needing no particular condition.

The closed route control mode, referring to Fig. 2, is different in that a speed meter is additionally provided in the open route control mode. The speed meter tests the

speed of the motor and feeds the data to the controller controlling the motor so that the speed of the motor may be adjusted automatically to obtain a stabilised speed of the motor. However, though the closed route control mode can provide control of the output of the motor, the object controlled is the motor itself, not the carrier. The rigidity (such as the gap between gears) and load characteristics of the electric carrier may not be such as that calculated by theory, thus potentially producing large errors, so those skilled in the art tend to offer theory about motor control and structural designs so as to acquire higher precision. But such a new method may increase cost, which is not easily accepted by many people.

SUMMARY OF THE INVENTION This invention has been devised to offer an electric carrier with a motor controlled by a relative positional mechanism, ergonomically conforming to human nature, having the driving speed of the electric carrier synchronous with that of the operator, thus being widely applicable to various industries.

According to the present invention, there is provided a carrier driven by an electric motor, the carrier comprising: a sensor, said sensor including a movable position reference member, a sensing body of said sensor producing a sensor signal in response to movement of said position reference member, a spring means connected to said position reference member, said spring means urging said position reference member toward a neutral position, a controller operated by said sensor signal generated by said sensing body, and a motor driven by said controller; wherein said motor drives said carrier, a speed and direction of drive of said motor being controlled by said controller, said spring means returning said position reference member to said neutral position when no force is applied to said position reference member such that there is no motion of said position reference member relative to said carrier, said motor therefore applying

no drive to said carrier when said position reference member is in said neutral position.

Features of the invention include a sensor controlled by an operator, a controller driven by a signal produced by the sensor controlled by the operator, a motor controlled by the controller, and an electric carrier driven by the motor. When the relative position (or speed difference) of the electric carrier and the operator changes, the sensor immediately senses this and sends a signal to the controller, which then controls the speed of the electric carrier so as to be increased or decreased, adjusting the speed of the electric carrier to that of the operator. Thus this kind of structure can permit the electric carrier to move with a synchronous speed with the operator so as to be widely utilised by various industries.

BRIEF DESCRIPTION OF DRAWINGS This invention will be better understood by way of example by referring to the accompanying drawings, wherein: Figure 1 is a block flow chart of a conventional open route control; Figure 2 is a block flow chart of a conventional closed route control; Figure 3 is a block flow chart of a controlling mode of an electric carrier with a motor controlled by a relative positional mechanism in the present invention; Figure 4 is a diagram of a first embodiment of an electric carrier with a motor controlled by a relative positional mechanism in the present invention, using two vehicles in motion; Figure 5 is a perspective view of a second embodiment of an electric carrier with a motor controlled by a relative positional mechanism in the present invention, utilised

in the handle of an electric golf cart to be pulled to control the speed of the electric golf cart; Figure 6 is a perspective view of the handle pulled in the opposite direction to that shown in Fig. 5; Figure 7 is a view of stationary conditions of a first example of a sensor in an embodiment of the present invention; Figure 8 is a view of dynamic changes and 1/O points of the relative conditions in Fig. 7; Figure 9 is a view of stationary conditions of a second example of a sensor in an embodiment of the present invention; Figure 10 is a view of dynamic changes and 1/O points of the relative conditions in Fig. 9; Figure 11 is a view of stationary conditions of a third example of a sensor in an embodiment of the present invention; Figure 12 is a view of dynamic changes and 1/O points of the relative conditions in Fig. 11; Figure 13 is a view of stationary conditions of a fourth example of a sensor in an embodiment of the present invention; Figure 14 is a view of dynamic changes and 1/O points of the relative conditions in Fig. 13;

Figure 15 is a view of stationary conditions of a fifth example of a sensor in an embodiment of the present invention; Figure 16 is a view of dynamic changes and 1/O points of the relative conditions in Fig. 15; Figure 17 is a graph of the speed set with the first parameter and the position of the sensor shown in Fig. 7; Figure 18 is a graph of the speed set with the second parameter and the position of the sensor shown in Fig. 7; Figure 19 is a graph of the speed and the position of the sensor shown in Fig. 9; Figure 20 is a graph of the speed and the position of the sensor shown in Fig. 11; Figure 21 is a side view of the third embodiment of the present invention applied to a bicycle for controlling its speed; Figure 22 is a magnified side view of the sensor shown in Fig. 13 applied to a bicycle; Figure 23 is a view of the fourth example of an embodiment applied to a wheelchair for controlling its speed; Figure 24 is a front view of a magnetic switch used as a sensor in Fig. 23; Figure 25 is a side view of the magnetic switch used as a sensor in Fig. 23; Figure 26 is a front view of the dynamic changes of the magnetic switch shown in Fig. 24;

Figure 27 is a perspective view of an embodiment in the present invention, showing springs added on the sensor when it is used for linear movement; Figure 28 is a front view of the embodiment in the present invention, showing springs added on the sensor when it is used for circular or rotational movement; and Figure 29 is a side view of Fig. 28.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an electric carrier with a motor controlled by a relative positional mechanism, as shown in Fig. 4, includes a vehicle as an operator 10, another vehicle as an electric carrier 20,a position reference member 40 controlled by the operator 10 and located between the both 10 and 20, a sensor 41 affixed on the electric carrier 20, a controller receiving a signal from the sensor 41, and a motor fixed on the electric carrier 20 and controlled by the controller.

The sensor 41 utilises the relative position of the electric carrier 20 and the main operator 10, transmitting proper command to the controller, which then controls the speed of the motor so as to be increased or decreased. When the operator 10 moves forward, the sensor 41 is driven, and next the controller, and the motor to move the electric carrier 20. In other words, the electric carrier 20 may be deemed as a subordinate, and when the relative position between the operator 10 and the electric carrier 2Q changes, the sensor 41 at once senses this and sends a signal to the controller. Then the controller controls the speed of the subordinate to increase or decrease so that the speed of the operator and the subordinate may be synchronous or the same. Although the subordinate can be considered to be a load pulled by the operator, the subordinate does not in fact make up a load of the operator, and various practical things may be designed according to this idea. For example, the sensor, the controller, the motor may be such as to be used in the preferred embodiments described below.

Next., Figs. 5 and 6 shows a second embodiment of the invention, applied to a handle 31 of an electric golf cart 30 for controlling the speed of the electric golf cart. Its controlling mode is shown in Figs. 7 and 8, including a position reference member 40 (such as a carbon brush, a magnet, a photosensitive gate, a metal, etc.) pulling to move a handle 31, a sensor 41 (such as a printed electric circuit, a magnetic switch, a photosensitive switch, or a metal sensor) sensing the position of the position reference member 40 and sending out a signal, and a controller 42 receiving a signal from the sensor 41. The controller 42 may be a motor on the electric golf cart to move the cart. The controller 42 may thus be considered:to be a motor driver. Then Fig. 7 may be taken as a whole sensor, and for convenience of explanation, the position reference member 40 is considered as a carbon brush, and the sensor 41 a copper foil, and the carbon brush is a contact point (indicated as GND in Fig. 7). If the controller 42 has three 1/O points BIT2, BIT1, BITO for sensing the carbon brush, and the carbon brush is designed to contact the copper foil, with the I/O point being low (0) or high (1), the three I/O points may have the five conditions (011), (001), (10l), (100), and (110) as shown in Fig. 8, with the carbon brush being at different positions. Consequently the controller may have five increasing and decreasing positions and these positions are effected by the relative coordination of the sensor 41 and the position reference member 40. Accordingly the sensor 41 may have many different shapes, not limited to only one shape, and more than five controlling positions for increasing and decreasing the speed can be designed, as shown in Figs. 9, 11 and 15 and may present more than five controlling conditions to increase and decrease the speed, as shown in Figs. 10 12, and 16. Alternatively, as shown in Fig. 13, the sensor 41 may be made curve-shaped and still have five ways to increase or decrease the speed, as shown in Fig. 14. Thus different modes may have different ways to increase and decrease the speed to provide a comfortable operating feeling by utilising different parameters. As in Fig. 18, with the horizontal axis being time and the vertical axis speed, if a user pulls the handle 31 of an electric golf cart 30 and there are five ways of increasing and decreasing the speed as shown in Fig. 17, the motor of the electric golf cart slowly starts to drive the cart. Alternatively, if

time T of the accelerating curve changes relative to speed V as shown in Fig. 18, the motor of the electric golf cart 30 starts quickly.

To explain more precisely, utilising alteration of the parameter (meaning inclination percentage or gradient of the relation between speed increasing and decreasing and time) can drive the motor slowly or quickly, and produce time change to provide a comfortable operating feeling. Basically, control of the aforesaid I/O point output signal can be accomplished by means of a micro processor, with a very high accuracy. At the same time, the micro processor can perform changes by different accelerating parameters, as shown in Figs. 17, and 18, and different accelerating parameters may produce accelerating speed curves of different inclination percentage or gradient. An electric carrier needing a soft or slow start may use the parameter shown in Fig. 17, and that needing a large start torque may use the parameter shown in Fig. 18. In addition, 1/O can be used to control clockwise or counterclockwise rotation of the motor, as shown in Fig. 9, wherein the four 1/O points have ten conditions, (0111), (0011), (1011), (1001), (1101), (1100), (1000), (1010), (0010), (0110). If the lowest BITO being low 0 is used for controlling two directional motion, its accelerating curve is as shown in Fig. 19, wherein + and - of the vertical axis in the figure indicate clockwise and counterclockwise rotation of the motor. By the same principle, setting different parameters for different modes can acquire different increasing and decreasing ways of speed. If the controller has five I/O points for sensing the position of the carbon brush as shown in Figs. 11 and 15, the five points may have nine changes, (01111), (00 111), (10111), (10011), (11011), (11001), (11101), (11100), and (11110). Setting of the parameter in coordination of the accelerating curve shown in Fig.20 can acquire a function for controlling clockwise and counterclockwise rotation of the motor.

As can be understood from the aforesaid description, if the operator is a person, (referring to Fig. 3 also) and the handle of the electric golf cart is considered to be the sensor, the golf cart can change the speed of the motor to that of the person operating the handle, obtaining the function of synchronous movement of the electric carrier with the person. Besides, as shown in Figs. 21 and 22, the speed controlling modes in the embodiment of the invention can also use a circular or rotational movement with coordination of the sensor shown in Fig. 13 or 15. So only changing the parameter can obtain the function of driving. For example, the design of the circular or rotational movement control can be applied to a bicycle 60, utilising the relation of a pedal disc 61 and a disc 62 rotating together with the motor, letting the circular or rotational movement of the pedal disc 61 send an output to drive the motor in the multistage speed increasing and decreasing mode as shown in Figs. 14 and 16. In a practical design, the motor does not need counterclockwise rotation, as a bicycle runs only forward. So assistance by the motor can obtain the function of supplementary movement for a bicycle, having a high practicality. This embodiment can also be applied to a wheelchair 7, which has two hand-pushed wheels 70, two rolling wheels 71, two unmoveable discs 73, and two control discs 73 as shown in Fig. 23. The relative position of the unmoveable discs 72 and the control discs 73 is shown in Fig. 24. The five I/O points may be replaced by five switches (such as non-contact magnetic switches), which are turned on by a magnet coming near the switches. So a magnet 74 can be placed at a special location of the magnetic switch as shown in Fig. 24 and 25. Then if the magnetic switch has five I/O points and the control discs 73 in Fig. 24 have a bias to the corresponding discs, different magnets 74 can let different relative switches turn on. Thus only one or two magnetic switches coming near the magnet may be turned on because of the separate location angle of the switches. The dynamic changes and the 1/O output are shown in Fig. 26. Thus setting the parameter can acquire the effect of different speed control.

As can be understood from the aforesaid description, Figs. 5, 21 and 23 show the operator or a person practically commanding the speed, and the control flow chart is shown in Fig. 3. Therefore, whether the control capacity is good or bad can be perceived by the person, and the person can set the parameter according to the practical condition. If the three examples shown in Figs. 5, 21 and 23 are set as an auxiliary mode, the person (or the operator 10) should make the subordinate (or the electric carrier 20, the electric golf cart, or the hand-moved wheels 70 of the wheelchair) with his/her own force. In order to attain this, the position reference member 40 (such as a carbon brush) has to move together with the main operator 10, as shown in Fig. 27. Furthermore, the sensor 41 (such as a sectional electric circuit board) has to move together with the subordinate (or the electric carrier 20), and springs 80 have to be provided between the sensor 41 and the subordinate, in spite of linear or circular or rotational movement, as shown in Figs. 27, 28 and 29. On the one hand, the object is to permit the position reference member 40 automatically to return to its neutral position, not to be prevented by the pulling force of the operator 10, notwithstanding the pulling force being large or small. Then control stability may be secured. On the other hand, the pulling or pushing force of a person is to be transmitted to the electric carrier 20 (or the subordinate) via the springs 80. Interpreting this by taking mathematical extremes, when the springs 80 have limitlessly large elasticity, the position reference member 40 stays at zero or does not move. Then the motor also does not operate, and the electric carrier 20 is completely moved by the operator 10, forming a traditional towed vehicle without power. On the contrary, if the springs 80 have limitlessly small elasticity, the position reference member 40 is totally controlled by the operator 10, but the force of the operator 10 is impossible to be transmitted to the electric carrier 20, which is then moved completely by the motor, becoming a real electric car. Thus choosing proper springs 80 (changing the coefficient or force constant k of the springs 80) can make a supplementing car movement. In the same way, the pushing wheels 70 of the wheelchair shown in Fig. 29 may be considered to be the operator 10, and the rolling wheels 71 to be the subordinate (or the electric carrier 20), the same driving effect will be obtained. In designing the structure, if the springs can be pressed with a

preset pressure value (or adjusting its coefficient or force constant) as shown in Fig. 27, a threaded rod 81 with the front and the rear end respectively provided with a right-hand thread 81A and a left-hand thread 81B can be used, and the left-hand and the right-hand thread 81 B and 81 A respectively carry a front and a rear stop plate 90 and 91 pushed by the springs 80. When the threaded rod 81 is rotated, the stop plates 90, 91 are respectively moved toward the centre, compressing the springs 80. With this design, a user himself can adjust the assisting force of the motor depending on his body strength at that time, and the design is very practical to use. It should be emphasised that the central ideology of the present invention is based on a human person, not on comfortable operation by a human person, not as on the motor without life that is used in conventional electric carriers. If the present invention is required to drive the electric carrier, the operator only resists the elasticity of the springs fixed on the carrier, accomplishing the effect of assisting movement as mentioned above in the description of the invention. Therefore, this invention may be widely utilised in the market (such as on electric wheelchairs, electric golf carts, etc.). Although this invention uses a motor as power source, a human person feels that the movement of the object is controlled completely by himself, satisfying a demand for personalised operation. So it is evident that the present invention is superior to conventional carriers, which lack personalised designs and are liable to produce errors in their control.

Claims

CLAIMS: 1. A carrier driven by an electric motor, the carrier comprising: a sensor, said sensor including a movable position reference member, a sensing body of said sensor producing a sensor signal in response to movement of said position reference member, a spring means connected to said position reference member, said spring means urging said position reference member toward a neutral position, a controller operated by said sensor signal generated by said sensing body, and a motor driven by said controller; wherein said motor drives said carrier, a speed and direction of drive of said motor being controlled by said controller, said spring means returning said position reference member to said neutral position when no force is applied to said position reference member such that there is no motion of said position reference member relative to said carrier, said motor therefore applying no drive to said carrier when said position reference member is in said neutral position.
2. The carrier of claim 1 wherein: said position reference member is a carbon brush.
3. The carrier of claim 1 wherein: said position reference member is a magnet. 4. The carrier of claim 1 wherein: said position reference member is a photo- or light-gate. 5. The carrier of claim 1 wherein: said position reference member is a metal.

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6. The carrier of claim 1 wherein: said sensing body is a printed electric circuit board. 7. The carrier of claim 1 wherein: said sensing body is a magnetic switch. 8. The carrier of claim 1 wherein: said sensing body is a photosensitive switch. 9. The carrier of claim 1 wherein: said sensing body is a metal sensor. 10. A carrier driven by an electric motor, substantially as hereinbefore described with reference to Figures 3 to 29 of the accompanying drawings.

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Amendments to the claims have been filed as follows CLAIMS: 1. A carrier driven by an electric motor, the carrier comprising: a sensor, said sensor including a movable position reference member, a sensing body of said sensor producing a sensor signal in response to movement of said position reference member, a spring means connected to said position reference member, said spring means urging said position reference member toward a neutral position, a controller operated by said sensor signal generated by said sensing body, and a motor driven by said controller; wherein said motor drives said carrier, a speed and direction of drive of said motor being controlled by said controller, said spring means returning said position reference member to said neutral position when no force is applied to said position reference member such that there is no motion of said position reference member relative to said carrier, said motor therefore applying no drive to said carrier when said position reference member is in said neutral position; wherein the position reference member, the controller and the motor are adapted to adjust the speed and direction of drive of the motor in response to movements of an external operator having a means of attachment to the position reference member such that when the external operator moves faster or slower than the carrier, the position reference member is moved to a position which causes the controller to increase or decrease the speed of the motor so that the carrier adjusts its speed to that of the operator. 2. The carrier of claim 1 wherein: said position reference member is a carbon brush. 3. The carrier of claim 1 wherein: said position reference member is a magnet.

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4. The carrier of claim 1 wherein: said position reference member is a photo- or light-gate.
5. The carrier of claim 1 wherein: said position reference member is a metal.
6. The carrier of claim 1 wherein: said sensing body is a printed electric circuit board.
7. The carrier of claim 1 wherein: said sensing body is a magnetic switch.
8. The carrier of claim 1 wherein: said sensing body is a photosensitive switch.
9. The carrier of claim 1 wherein: said sensing body is a metal sensor.
10. A carrier driven by an electric motor, substantially as hereinbefore described with reference to Figures 3 to 29 of the accompanying drawings.