JP2010085387A - Visual dynamic display device, visual dynamic science text, and science toy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual dynamic display device as a science text, capable of visually recognizing both of the magnitude and direction of dynamics. <P>SOLUTION: The visual dynamic display device 10 includes: a three-axis acceleration sensor 20A; a filter amplifier circuit 30 for applying noise elimination processing to acceleration information in three-axis direction detected by the acceleration sensor 20A; a controller 40 for generating display information based on acceleration information; and a display 50 having an x-, y-, and z-axis display unit displaying the direction and magnitude of dynamics working in three-axis direction based on the display information. The filter amplifier circuit 30 reduces a cut-off frequency fz applied to the z-axis acceleration information to be smaller than a cut-off frequency fx, fy (fx=fy) applied to the x-axis and y-axis acceleration information. Further, by permitting the visual dynamic display unit 10 to tilt only around y-axis, gravitation is broken down into x-axis and z-axis components to be displayed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus that can visually recognize the magnitude and direction of a force acting on an object.

  In the field of school education, crying away from science. One reason for this is that some of the things handled in science are not visually recognizable. One example is the concept of power. In other words, since the force is invisible, the size and orientation cannot be grasped visually, making it one of the difficult things for junior and senior high school students. Therefore, there is a need for teaching materials that can visualize the magnitude and direction of the force acting on an object in an educational setting.

  Various tilt sensors have been proposed in which two-axis (or three-axis) accelerations orthogonal to each other are detected by an acceleration sensor to obtain an angle formed by a reference direction and gravitational acceleration, that is, a tilt angle (Patent Documents 1 and 2). .

Japanese Patent No. 3114571 JP 2008-96355 A

Finding the angle of inclination using an accelerometer gives suggestions for recognizing the direction of the force, but a report that a device that visualizes both the magnitude and direction of force has been proposed I can't find it.
The present invention has been made based on such a problem, and an object thereof is to provide a visual force display device capable of visually recognizing both the magnitude and direction of force.

The present inventors have conducted a study on the premise that an intended visual force display device is obtained using an acceleration sensor, and some problems have been extracted.
<Display of gravity>
One challenge is to display gravity.
One of the forces acting on objects is gravity. Therefore, the target visual force display device needs to indicate that gravity is always acting on the object, that is, the visual force display device.
Here, in principle, the acceleration sensor measures an inertial force when performing an acceleration motion. For example, when the acceleration motion is performed in the x-axis direction (horizontal direction), the acceleration sensor receives an inertial force in the reverse direction and outputs this as a voltage signal. This indicates that in order to display the direction of the force actually applied to the visual force display device, it is only necessary to display in the reverse direction of the voltage output.

  However, since gravity always works in the z-axis direction, the acceleration sensor outputs acceleration in the direction opposite to gravity even when the visual force display device is stationary. This can be interpreted as a force and corresponds to the normal force received from the surface on which the visual force display device is placed. On the other hand, when the acceleration sensor is falling freely (or being thrown up), the inertial force and the gravity cancel each other, and the output of the acceleration sensor in the z-axis direction becomes 0 (zero). That is, if the output of the acceleration sensor is displayed as it is, the gravity acting on the visual force display device cannot be displayed in any case. This is inadequate as a learning material.

  In response to the problem of displaying gravity, the present inventors have artificially displayed gravity on the visual force display device. Specifically, the force of the same magnitude as the output of the acceleration sensor corresponding to the normal force and the reverse force is regarded as gravity acting on the visual force display device and is displayed on the visual force display device.

<Response to slope movement>
The science of junior high school deals with the acceleration motion of the carriage on the slope. In order to cope with this, the visual force display device needs to detect its own inclination. However, since the inclination and the acceleration motion in the lateral direction are equivalent and cannot be distinguished, it is necessary to set some constraint condition to obtain the inclination. Therefore, in the present invention, since it is a science teaching material, the inclination is obtained from the output in the z-axis direction from the acceleration sensor on the premise that “acceleration motion does not occur in the z direction”. Specifically, the inclination θ is determined by cos θ = az / g. Here, az represents the component of gravity in the z-axis direction, that is, acceleration (information) in the z-axis direction, and g represents gravity acceleration.
Furthermore, the direction of tilting the visual force display device according to the present invention is limited to the y axis. Thereby, the component along the slope of gravity, that is, the component cx in the x-axis direction of gravity can be obtained from cx = (g ² -az ² ) ^1/2 . When the acceleration az in the z-axis direction is smaller than the gravitational acceleration g, the gravity in the x-axis direction together with the gravity in the z-axis direction is displayed based on the above formula.

<Noise removal>
Since the acceleration sensor originally has a band up to about 1 KHz, sound is picked up as noise. In the visual force display device according to the present invention, noise removal is realized by analog-to-digital conversion (AD conversion) after passing the signal from the acceleration sensor through the low-pass filter. Here, by making the cut-off frequency of the z-axis smaller than the cut-off frequencies of the x- and y-axes, it is difficult to detect acceleration motion in the z-axis direction, and it is possible to cope with the above-described gravity display and slope motion. Realized. The cut-off frequency of the specific Low-Pass filter of the present invention was set to 10 Hz for the x and y axes and 0.25 Hz for the z axis as a result of trial and error.
The above is the case where the acceleration sensor outputs analog information, but the same can be considered when a digital acceleration sensor is used. In this case, the Low-Pass filter is also realized by digital signal processing inside the controller.

  The visual force display device of the present invention (hereinafter simply referred to as a force display device) based on the above examination results includes an acceleration sensor that detects acceleration in the x-axis direction and acceleration in the z-axis direction orthogonal to the x-axis direction. A filter that performs noise removal processing on the acceleration information ax in the x-axis direction and the acceleration information az in the z-axis direction detected by the acceleration sensor, and display information dx is generated based on the acceleration information ax that has been noise-removed by the filter. A controller that generates display information dz based on acceleration information az that has been subjected to noise removal processing by a filter; an x-axis display that displays the direction and magnitude of a force acting in the x-axis direction based on display information dx; Display means having a z-axis indicator that displays the direction and magnitude of the force acting in the z-axis direction based on the display information dz, and the filter is a clip applied to the acceleration information az. Off frequency fz, characterized by less than the cut-off frequency fx to be applied to the acceleration information ax.

  Although the above has shown the case of two dimensions as the minimum element for displaying force, it goes without saying that the present invention can also be applied to three dimensions. That is, the present invention includes an acceleration sensor that detects acceleration in the x, y, and z axis directions, a filter that performs noise removal processing on three-axis acceleration information ax, ay, and az detected by the acceleration sensor, and noise removal by the filter. A controller that generates display information dx, dy, and dz based on the processed acceleration information ax, ay, and az, and a force that acts in the x, y, and z-axis directions based on the display information dx, dy, and dz, respectively. An x-axis, y-axis, and z-axis display for displaying the orientation and size, respectively, and the filter uses a cutoff frequency fz applied to the acceleration information az and a cutoff frequency fx, fy applied to the acceleration information ax and ay. It is characterized by making it smaller. It should be noted that fx and fy can be equal.

In the force display device of the present invention, the controller generates display information dz ′ having the same size and the opposite direction as the display information dz, and the z-axis display displays both the display information dz and the display information dz ′. By doing so, the problem of gravity display is addressed.
Further, in the force display device of the present invention, the controller determines the component cx in the x-axis direction of gravity based on the acceleration az in the z-axis direction, thereby responding to the problem related to the motion of the slope.
In the force display device of the present invention, the controller displays the y-axis direction as it is based on the acceleration ay in the y-axis direction.
The force display device according to the present invention as described above can be used as a science teaching material in an educational field and further as a scientific toy.

  Since the force display device of the present invention can visually recognize the magnitude and direction of the force acting on an object, it is suitable as a teaching material or a scientific toy that makes middle and high school students understand the concept of difficult force.

It is a perspective view which shows the external appearance of the force display apparatus in this Embodiment. It is a block diagram which shows the structure of the force display apparatus in this Embodiment. It is a flowchart which shows the procedure of the process in the controller in the force display apparatus of this Embodiment. It is a flowchart which shows the process sequence of the raw data in the controller in the force display apparatus of this Embodiment. It is a figure which shows how to obtain | require the inclination in the force display apparatus of this Embodiment. An example of the table which defines the number of LED lighted according to the component cx of the x-axis direction of gravity is shown. (A) Illumination of the LED of the force display device when stationary on a horizontal plane is shown, and (b) is a diagram showing the illumination of the LED of the force display device falling horizontally. (A) Illumination of the LED of the force display device when linear acceleration motion is performed on the horizontal plane under external force, and (b) Illumination of the LED of the force display device that performs linear linear motion on the horizontal surface without receiving external force. FIG. (A) It is a figure which shows lighting of LED of the force display apparatus which rests on an inclined surface, (b) It is a figure which shows lighting of LED of the force display apparatus which slides freely on an inclined surface. (A) A state in which the force display device 10 is placed and rotated on the end of a disk that freely rotates around the axis S is shown, and (b) a lighting state of the LED of the force display device 10 at that time. is there. It is a block diagram which shows the structure of the force display apparatus in this Embodiment, and shows the case where the acceleration sensor which outputs digitally is used.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a perspective view showing an appearance of a force display device 10 according to the present embodiment, and FIG. 2 is a functional block diagram of the force display device 10.
The force display device 10 includes a triaxial acceleration sensor 20A (hereinafter simply referred to as an acceleration sensor 20A), a filter / amplifier circuit 30 that receives and filters acceleration information including a DC voltage signal obtained by the acceleration sensor 20A, and a filter A controller 40 that receives and processes information processed by the amplifier circuit 30 and generates control information, and a display unit 50 in which the light emitting diode LED is turned on based on the control information generated by the controller 40 The
In FIG. 2, the acceleration sensor 20 </ b> A is illustrated on the assumption that analog output is performed, but an acceleration sensor 20 </ b> D having a digital output can be used. However, in that case, as shown in FIG. 11, the filter / amplifier circuit 30 is not required, and the filter processing is executed in software in the controller 40.

  The force display device 10 includes a rectangular parallelepiped case 11 having two adjacent surfaces as an xz display surface 12 and an xy display surface 13. The case 11 is configured by assembling a transparent acrylic resin plate, for example.

<Display unit 50>
An xz display substrate 14 is provided inside the xz display surface 12 of the case 11, and an xy display substrate 15 is provided inside the xy display surface 13. On the xz display board 14 and the xy display board 15, a plurality of indicator lamps each composed of a light emitting diode LED are arranged in a cross shape to form an xz display 16 and an xy display 17. . The display unit 50 is configured by the two displays 16 and 17. The x-axis, y-axis, and z-axis are as indicated by arrows in FIG. The necessary number of light emitting diodes LED constituting the xz display 16 and the xy display 17 are turned on based on display information generated by the controller 40, and the direction and magnitude of the acting force are displayed.
The xz display 16 forms a cross by arranging 10 LEDs in the x direction and 10 LEDs in the z direction on a straight line. The xy indicator 17 also forms a cross by arranging 10 LEDs in the x direction and 10 LEDs in the y direction on a straight line. In the xz display 16 and the xy display 17, positive (+) and negative (−) are determined as shown in the figure, with the crossing portion (origin) as a center. For example, in the xz display 16, when an LED corresponding to the negative z-axis is lit, this indicates that the force display device 10 is receiving gravity. The force display device 10 indicates that 0.25 g (g: gravitational acceleration) is acting when one LED is lit.

<Acceleration sensor 20A>
The force display device 10 includes an acceleration sensor 20 </ b> A in the case 11. The acceleration sensor 20A is arranged in the case 11 so that each of its three axes (x, y, z) is along the x-axis, y-axis, and z-axis of the force display device 10 shown in FIG.
When the force display device 10 performs an acceleration motion, the acceleration sensor 20A receives an inertial force opposite to the acceleration motion and outputs acceleration as a voltage signal in each of the x-axis, y-axis, and z-axis directions. Note that the magnitude and direction of the force can be recognized by displaying the acceleration from the equation of motion F = m × a.

<Filter / Amplifier Circuit 30>
The force display device 10 includes a filter / amplifier circuit 30 in the case 11.
The filter / amplifier circuit 30 removes unnecessary noise by filtering the voltage signal sent from the acceleration sensor 20A. Here, the filter / amplifier circuit 30 includes an x-axis filter 31, a y-axis filter 32, and a z-axis filter 33, and three filter elements (low-pass filter). The voltage signal in the x-axis direction of the acceleration sensor 20A is filtered by the x-axis filter 31. Similarly, the voltage signal in the y-axis direction of the acceleration sensor 20A is filtered by the y-axis filter 32, and the z-axis direction of the acceleration sensor 20A. The z-axis filter 33 performs a filtering process on the voltage signal.

The filter / amplifier circuit 30 sets the cutoff frequency of the z-axis filter 33 to be smaller than that of the x-axis filter 31 and the y-axis filter 32. Specifically, the cutoff frequency of the x-axis filter 31 and the y-axis filter 32 is set to 10 Hz, and the cutoff frequency of the z-axis filter 33 is set to 0.25 Hz. Thus, by reducing the cutoff frequency in the z-axis direction (increasing the period), the influence of vibration in the z-direction is suppressed as much as possible. This is made on the assumption that this device does not perform acceleration motion in the z-axis direction. When the output in the z-axis direction changes due to vibration, gravity is specified based on the vertical drag in the z-axis direction, which will be described later. This is because the process and the process of specifying the component of gravity in the x-axis direction cannot be executed smoothly.
After a predetermined filtering process is performed in the filter / amplifier circuit 30, the acceleration signal is amplified and then output to the controller 40.
The filter / amplifier circuit 30 is required only when the acceleration sensor 20A has an analog output. In the case of the acceleration sensor 20 </ b> D having a digital output, the filtering process is executed in software inside the controller 40 instead of the omitted filter / amplifier circuit 30.

<Controller 40>
The controller 40 performs analog-to-digital conversion (AD conversion) on the analog acceleration information signals about the x-axis, y-axis, and z-axis filtered by the filter / amplifier circuit 30 and converts them into digital signals, and then performs predetermined arithmetic processing.
The controller 40 can be constituted by, for example, a PIC (Peripheral Interface Controller). The PIC is a one-chip microcomputer in which an arithmetic processing unit, a memory, an input / output unit, and the like are incorporated in one IC, and is controlled by software.

3 and 4 show procedures of AD conversion and arithmetic processing in the controller 40. FIG.
As shown in FIG. 3, the controller 40 processes acceleration information signals (raw data) regarding the x-axis, y-axis, and z-axis received from the filter / amplifier circuit 30, and turns on the light-emitting diode LED of the display unit 50. It is displayed (FIG. 3, S101, S103, S105). As shown in FIG. 4, when the controller 40 obtains an analog voltage signal (raw data), the raw data is processed by AD conversion to generate display information (S201, S203 in FIG. 4), and the light emitting diode LED to be displayed. (S205 in FIG. 4), and then the LED is turned on (S207 in FIG. 4). As described above, since one LED corresponds to 0.25 g, when the display information d is 0.125 g <d ≦ 0.375 g, one LED is turned on, and similarly 0.375 g <d ≦ In the case of 0.625 g, two light sources may be lit, and in the case of 0.625 g <d ≦ 0.875 g, three light sources may be lit. When d is smaller than 0.125 g, no LED is lit.

  The controller 40 displays the gravity in the z-axis direction acting on the force display device 10 on the display unit 50 in addition to the process of AD-converting the raw data of the x-axis, y-axis, and z-axis to turn on the light emitting diode LED. For this purpose (S107 in FIG. 3). As described above, if the output of the acceleration sensor 20A is displayed as it is, the gravity acting on the force display device 10 cannot be displayed. Therefore, the controller 40 generates AD-converted raw data in the z-axis direction, that is, display information indicating a reverse force having the same magnitude as the vertical drag, and uses the light-emitting diode as gravity acting in the z-axis direction. Turn on the LED.

Further, the controller 40 displays the gravity in the x-axis direction acting on the force display device 10 on the display unit 50 in addition to the process of generating the display information by performing AD conversion on the raw data regarding the x-axis, the y-axis, and the z-axis. The process for making it perform is performed (FIG. 3 S109).
As described above, the force display device 10 needs to detect its own inclination, but since the inclination and the acceleration motion in the lateral direction are equivalent, it is necessary to set some condition to obtain the inclination. Therefore, the controller 40 determines the inclination from the raw data in the z-axis direction on the assumption that the force display device 10 does not make an acceleration motion in the z-axis direction. That is, as shown in FIG. 5, it is assumed that the force display device 10 is placed on a surface (tilt = θ) that is inclined downward on the positive (+) side of the x axis. At this time, since g and az (raw data in the z-axis direction) are known, the inclination θ can be obtained from the equation (1).
cos θ = az / g (1)

Therefore, the component cx of gravity in the x-axis direction can be obtained by Expression (2).
cx = (g ² -az ² ) ^1/2 (2)
However, in the expression (2), the sign (positive / negative) of cx is determined by the output signal (acceleration information) ax of the accelerometer in the x-axis direction. When the acceleration az in the z-axis direction is smaller than the gravitational acceleration g, the gravity in the x-axis direction and the gravity in the z-axis direction are displayed using the above equation.

  When the controller 40 is composed of a PIC, the square root in the equation (2) cannot be calculated by the PIC. The resolution of the display 16 (17) is 4 bits. Therefore, the controller 40 holds a table corresponding to the expression (2) in the memory, and when the acceleration az in the z-axis direction is obtained, the number of LEDs in the x-axis direction to be lit is referred to this table. Can be determined. In this table, for example, as shown in FIG. 6, the acceleration az in the z-axis direction is associated with the number of LEDs to be lit.

Now, an example of actually visualizing and displaying the force using the force display device 10 will be described in the following order. Although the xz display 16 will be mainly described here, it goes without saying that the xy display 17 can be similarly turned on and displayed as described in (VII).
(I) Still on horizontal plane ... Fig. 7 (a)
(II) Free fall (or throwing up) ... Fig. 7 (b)
(III) Linear acceleration motion on the horizontal plane (with external force) ... Fig. 8 (a)
(IV) Constant-velocity linear motion on the horizontal surface (no external force) ... Fig. 8 (b)
(V) Still on the inclined surface ... Fig. 9 (a)
(VI) Free sliding on the inclined surface ... Release of static state ... Fig. 9 (b)
(VII) Rotating motion ... Fig. 10

(I) When the static force display device 10 is placed on the horizontal plane (FIG. 7A), gravity and vertical drag from the horizontal plane act on the force display device 10. Gravity acts downward in the z-axis direction, and normal drag acts upward in the z-axis direction. However, as described above, gravity cannot be measured by the acceleration sensor 20 </ b> A of the force display device 10. Therefore, as described above, the force display device 10 regards the force having the same magnitude and the opposite direction as the vertical drag from the horizontal plane measured by the acceleration sensor 20A.
When the force display device 10 is placed on a horizontal plane, the gravity and the vertical drag are balanced, and the xz display 16 has four LEDs on the positive (+) side in the z-axis direction and a negative ( The four LEDs on the-) side are lit.
Four LEDs on the positive (+) side represent vertical drag, and four LEDs on the negative (−) side represent gravity. A person who has seen this is perpendicular to gravity on the object (force display device 10). It is possible to visually recognize that the drag is acting.

(II) Free fall (or throwing up)
When the force display device 10 is allowed to fall freely with the x + axis facing downward, the normal force acting when it is placed on the horizontal plane does not act. However, gravity acts on the force display device 10. Therefore, as shown in FIG. 7B, only the four LEDs on the positive (+) side in the x-axis direction of the xz display 16 are turned on.
The four LEDs facing downward (+ side) represent gravity, and a person who sees this can visually recognize that only gravity acts on the object (force display device 10) during free fall.
Similarly, when the force display device 10 is thrown up, similarly, only four LEDs on the positive (+) side in the x-axis direction of the xz display 16 are turned on.
It should be noted that free fall or throw-up experiments must be performed with the positive (+) side in the x-axis direction facing downward. This is because, as described above, the force display device 10 is programmed on the assumption that no acceleration motion is performed in the z-axis direction.
In the above description, the direction of free fall is the x-axis positive (+) direction, but the same display is made in the x-axis negative (−) direction. However, it should not fall freely in the y-axis direction. This is because the force indicator 10 only allows rotation about the y-axis when tilting.

(III) Linear acceleration motion on the horizontal plane (with external force)
For example, when the force display device 10 performs linear acceleration motion on a horizontal plane while being pressed by a hand, an external force F directed to the left in the drawing in the x-axis direction acts on the force display device 10. Accordingly, as shown in FIG. 8A, for example, three LEDs on the positive (+) side in the x-axis direction of the xz display 16 are turned on. In this case, the three LEDs that are lit indicate that the magnitude of the acceleration corresponding to the external force F is about 3/4 of g (gravity acceleration).
Further, when the force display device 10 accelerates on the horizontal plane while receiving the external force F, the force display device 10 is subjected to gravity and vertical drag from the horizontal plane. Therefore, in the xz display 16, four positive (+) LEDs in the z-axis direction and four negative (-) LEDs in the z-axis direction are lit.
As described above, the three LEDs on the positive (+) side in the x-axis direction of the xz display 16 represent the external force F, the four LEDs on the positive (+) side represent the vertical drag, and the negative (− The four LEDs on the) side represent gravity, and a person who has seen this is acting on the object (force display device 10) to the force display device 10 with an external force F, gravity and vertical drag in the rightward horizontal direction. Can be recognized visually.

(IV) Constant-velocity linear motion on the horizontal surface (no external force)
When the force display device 10 moves at a constant linear velocity on the horizontal plane, as shown in FIG. 8B, only the gravity and the vertical drag from the horizontal plane act on the force display device 10.
Therefore, in the xz indicator 16, four LEDs on the positive (+) side in the z-axis direction and four LEDs on the negative (−) side in the z-axis direction are turned on. Four LEDs on the positive (+) side represent vertical drag, and four LEDs on the negative (−) side represent gravity, and a person who has seen this is subject to gravity and vertical on the object (force display device 10). It can be visually recognized that the drag acts on the force display device 10.

(V) Standing on the inclined surface As shown in FIG. 5, when the force display device 10 is held on the inclined surface and supported by the support body 60, the force display device 10 includes the x-axis and z In each of the axial directions, a gravitational component and a normal force received from the inclined surface or the support 60 act. However, here, it is assumed that no friction acts between the inclined surface and the force display device 10. In this case, the forces should be balanced in the x-axis and the z-axis, respectively. Assuming that the inclination angle is θ, as shown in FIG. 5, the component cx of gravity in the x-axis direction is cx = (g ² −az ² ) ^{1/2 according} to the equation (2). The force display device 10 receives a drag D from the support body 60 in the horizontal direction with respect to the inclined surface. This drag D is equal in magnitude and opposite in direction to the component cx of gravity in the x-axis direction.

  Therefore, the xz indicator 16 is turned on, for example, three LEDs on the positive (+) side in the z-axis direction and three LEDs on the negative (−) side in the z-axis direction. Further, the xz indicator 16 is turned on by two LEDs on the positive (+) side in the x-axis direction and two LEDs on the negative (−) side in the x-axis direction. A person who sees this shows that gravity and normal drag are acting on the object (force display device 10) in the x-axis direction and the z-axis direction, and the forces are balanced in the x-axis direction and the z-axis direction, respectively. Can be visually recognized.

(VI) Free sliding on the inclined surface When the force display device 10 freely slides on the inclined surface without friction, the force display device 10 is subjected to gravity and vertical drag from the inclined surface. Assuming that the inclination angle is θ, as shown in FIG. 5, the component cx of gravity in the x-axis direction is cx = (g ² −az ² ) ^{1/2 according} to the equation (2). The normal force received from the inclined surface is the same in magnitude as the z-axis direction component of gravity, ie, the acceleration information az in the z-axis direction, and the direction is opposite.
Since the force display device 10 freely slides on the inclined surface, the force received is three of the component cx in the x-axis direction of gravity, the component az in the z-axis direction of gravity, and the normal force received from the inclined surface.

  Therefore, the xz indicator 16 lights up three LEDs on the positive (+) side in the z-axis direction and three LEDs on the negative (−) side in the z-axis direction. In the xz display 16, two LEDs on the positive (+) side in the x-axis direction are turned on. A person who sees this shows that gravity and normal drag act on the object (force display device 10) in the x-axis direction and the z-axis direction, and that the force display device 10 has a component cx in the x-axis direction of gravity. It can be visually recognized that it is accelerated by.

(VII) Rotational motion As shown in FIG. 10A, when the force indicator 10 is placed on the end of a disc 70 that can freely rotate around the axis S and the disc 70 is rotated, the force indicator 10 has a centripetal force. LED lights up as shown in Fig. 10 (b). In general, it is considered that centrifugal force acts on a rotating object, and actually centrifugal force acts on a rotating coordinate system. However, centripetal force is necessary for the force display device 10 as shown in FIG. 10A to make a circular motion with the disk. It is usually very difficult for students to understand this relationship. By using the present invention, it can be clearly shown that the centripetal force is acting on the rotating object.

Since the force display device 10 described above visually displays the magnitude and direction of the force, it is useful for students to understand the concept of force when used in an educational setting. Moreover, since the lighting state of the LED changes by allowing the force display device 10 to stand or move, the force display device 10 becomes a toy that attracts the interest of school children and infants.
As mentioned above, although this invention was demonstrated based on the force display apparatus 10, it cannot be overemphasized that this invention is not limited to this embodiment. For example, the force display device 10 has LEDs arranged in a cross shape, but may be arranged in a matrix.

10 ... force display device,
11 ... Case,
12 ... xz display surface, 13 ... xy display surface,
14 ... xz display substrate, 15 ... xy display substrate,
16 ... xz display, 17 ... xy display 20A, 20D ... 3-axis acceleration sensor 30 ... filter amplifier circuit,
31 ... x-axis filter, 32 ... y-axis filter, 33 ... z-axis filter 40 ... controller 50 ... display unit

Claims (6)

an acceleration sensor that detects acceleration in the x-axis direction and acceleration in the z-axis direction orthogonal to the x-axis direction;
A filter that performs a noise removal process on the acceleration information ax in the x-axis direction and the acceleration information az in the z-axis direction detected by the acceleration sensor;
A controller that generates display information dx based on the acceleration information ax noise-removed by the filter, and generates display information dz based on the acceleration information az noise-removed by the filter;
An x-axis indicator that displays the direction and magnitude of the force acting in the x-axis direction based on the display information dx, and the direction and magnitude of the force acting in the z-axis direction based on the display information dz. Display means having a z-axis display for displaying,
The filter is
A visual force display device, wherein a cutoff frequency fz applied to the acceleration information az is smaller than a cutoff frequency fx applied to the acceleration information ax. A three-dimensional acceleration sensor that detects acceleration in the z-axis direction indicating the vertical and acceleration in the x-axis and y-axis directions orthogonal to the z-axis direction;
A filter that performs noise removal processing on the acceleration information ax in the x-axis direction, the acceleration information ay in the y-axis direction, and the acceleration information az in the z-axis direction detected by the acceleration sensor;
Display information dx is generated based on the acceleration information ax subjected to noise removal processing by the filter, display information dy is generated based on the acceleration information ay subjected to noise removal processing by the filter, and noise removal processing is performed by the filter. A controller that generates display information dz based on the acceleration information az.
An x-axis indicator that displays the direction and magnitude of the force acting in the x-axis direction based on the display information dx, and the direction and magnitude of the force acting in the y-axis direction based on the display information dy. A y-axis display for displaying, and a z-axis display for displaying the direction and magnitude of the force acting in the z-axis direction based on the display information dz,
The filter is
A visual force display device, wherein a cutoff frequency fz applied to the acceleration information az is smaller than cutoff frequencies fx and fy applied to the acceleration information ax and ay. The controller is
Generating display information dz ′ having the same size and the opposite direction as the display information dz;
The z-axis indicator is
The visual force display device according to claim 1, wherein both the display information dz and the display information dz ′ are displayed. The controller is
The visual force display device according to any one of claims 1 to 3, wherein a component cx in the x-axis direction of gravity is determined based on a component az in the z-axis direction of gravity.   A visual science teaching material comprising the visual force display device according to claim 1.   A visual scientific toy comprising the visual force display device according to claim 1.

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