JP3048035B2 - Needle display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle type display device in which a display pointer is driven by a step motor.

[0002]

2. Description of the Related Art FIG.
And comprises a rotor 10a and a stator 10b. The rotor 10a is formed of a magnet, and a display pointer is attached to a rotation axis of the rotor 10a via a gear.

When a current flows through the phase φ1 of the stator 10b as shown in FIG.
A suction force is generated between the N pole and the N pole, and the rotor 10a rotates to face φ1 (0 ° in FIG. 9B). In this state, that is, when a pulse is applied to φ2 while a pulse is applied to φ1, the magnetic field generated from the stator 10b becomes a composite magnetic field of φ1 and φ2, and an S pole is generated at an intermediate position between φ1 and φ2. 10a is rotated 45 ° clockwise (45 ° in FIG. 9B).

[0004] Hereinafter, as shown in FIG.
By applying a pulse to the rotor 10a sequentially.
Rotate 5 ° at a time. Note that the motor 10 rotates 45 ° each time a drive pulse is input, but the display hands are geared down by a gear (not shown) and rotated by θ ₀ degrees.

[0005] In the conventional needle type display device, as shown in FIG. 10, N = (θ _M) from a designated position θ _M which is to be designated every predetermined time T and a current position θ _P which is designated by the current pointer. −θ _P ) / θ ₀ (1) The drive pulse N is calculated by performing the following calculation.

When the number N of drive pulses is calculated, FIG.
As shown in (A), N drive pulses are transmitted at time intervals of T _A. That is, when the current pulse motor is rotated clockwise, the current pulse motor is set to 0 in FIG.
°, at time t ₁ , φ1 =
_A drive pulse of 1, φ2 = 1 and a drive pulse of φ1 = 0, φ2 = 1 at t ₂ after the time T _A are sent to rotate the stepping motor.

For this reason, the hand does not fluctuate until the first pulse calculated in the next cycle T is sent after the Nth pulse is sent, and the hand changes in a stepwise manner. Was not smooth. A method of smoothing the deflection of the pointer is described in Japanese Utility Model Laid-Open Publication No. 64-6556.

[0008] In this method, as shown in FIG.
Let T be a pulse transmission interval for transmitting N pulses within a period T.
/ N, and the transmission of the first pulse is transmitted with a delay of time T / 2N. By controlling the pulse transmission start time and the transmission time interval, the movement of the pointer becomes smooth.

Here, assuming that the minimum pulse transmission time interval that can be followed by the step operation determined by the characteristics of the step motor is T _A , T / N ≧ T _A (2) Is averaged, and the first pulse is delayed. From FIG. 10 (B) and equation (2), T ≧ / 2NT _A (3) Therefore, the value of T can be made smaller than a certain value. Recognize.

[0010]

In a needle type display device driven by a stepping motor, a driving pulse is transmitted at a time interval longer than a minimum time which can be followed by the stepping operation of the stepping motor. Is required to have a good response to a change in the input signal and a smooth response.

The command angle θ _M shown in FIG. 11 shows an example in which the vehicle gradually increases the speed and accelerates to a constant speed. The solid line indicates the minimum time interval that can be followed by the stepping operation of the stepping motor as T _A, and the period T shown in FIG. 10 is T = 6T _A and T = 12 T _A. Shows the movement of the pointer swing when operated by the method described in (1).

Although this method improves the smoothness,
Since the difference is calculated for each period T, a response delay occurs in the entire region. Since the pulse transmission interval is changed for each period T, a rapid change occurs as shown in FIG. The smoothness is lost, and when the period T is increased, the period T is further increased or worsened. As described above, the period T cannot be made smaller than a certain numerical value. There are problems such as setting is quite difficult.

That is, as in the prior art, arithmetic control is performed for each predetermined time unit, that is, a difference is calculated for each cycle T,
As long as the method of changing the pulse transmission interval is not able to achieve both the quick response and smooth operation described above,
And the smoothness is also insufficient.

Each time a driving pulse is input to the pulse motor, the pointer moves by θ ₀ . The drive pulse for driving the step motor rapidly rises, and inertia such as a gear for transmitting the rotation of the pointer and the step motor to the pointer is added. The movement of the pointer causes a vibration phenomenon as shown by a solid line in FIG.

An object of the present invention is to provide an improved needle-type display device in which the movement of the hands is smooth and the response is smooth.

[0016]

Means adopted by the present invention to solve the above-mentioned problems will be described. First, before describing the means solved by the present invention, the principle of eliminating the vibration of the pointer generated at the rise and fall of the drive pulse according to the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 8A shows each phase φ described in FIG. 9B.
₂ shows a drive pulse applied to _n . The drive pulse is composed of a drive pulse a that rises from 0 to 1 and a drive pulse b that holds 1 and a drive pulse c that falls from 1 to 0.

The reason why the pointer 12 vibrates is that the driving pulse a
Or the pulse as c are those caused by sudden or down standing up or standing, in the case of rising of M in FIG. 8 in the period under T _P of the driving pulse as shown in (B) A sub-pulse is generated, and its duty ratio is gradually increased.

[0019] to generate the M sub-pulses within the period T _P of the driving pulse, as shown in FIG. 8 (C) in the case of falling, yet gradually reduce its duty ratio. By doing so, the drive of the step motor is eased, and the movement of the pointer becomes smooth.

The number M of sub-pulses is set so that the interval T _S between sub-pulses is sufficiently smaller than the operation time of the step motor. Further, in FIG. 8 (B) and (C) as a way to reduce the drive of the stepping motor, but so as to generate the M sub-pulses within the period T _P of the driving pulse, the drive pulse in FIG. 8 (D) Period T
_The time T _C smaller than the driving time of the step motor in _P
A sub-pulse is generated every time, and the duty ratio is changed to smoothly move the pointer.

Next, the means employed by the present invention will be described with reference to FIG. FIG. 1 is a basic configuration diagram of the present invention. In a needle type display device that drives the display pointer with a step motor,
A time-measuring means 1 for measuring the set time; and a difference between a designated position at which the display pointer is to be instructed each time the time-measuring means 1 measures the time and a current position designated by the current display pointer is large. When the difference is small, a long time is calculated when the difference is small, and a long time is calculated and set in the time counting means 1. M number of driving pulses calculated in the cycle of the drive pulse calculated by the time counting means 2 are calculated. A sub-pulse generating means 3 for generating a sub-pulse to drive a step motor; a driving pulse determining means 4 for determining whether the driving pulse changes from 0 to 1 or 1 to 0 at the start of a cycle; When the drive pulse determining means 4 determines that the drive pulse changes from 0 to 1 at the start of the cycle, the duty ratio of the pulse generated by the sub-pulse generating means 3 is gradually increased to 1
And duty ratio changing means 5 for gradually reducing the duty ratio of the sub-pulse when it is determined that the duty ratio changes to 0.

Further, the M sub-pulses generated by the sub-pulse generating means 3 are generated at equal intervals within the cycle of the driving pulse, and the duty ratio of the last sub-pulse to be changed by the duty ratio changing means 5 is determined by the driving pulse. 100% when changing from 0 to 1; 0% when changing from 1 to 0
To

The sub-pulse generated by the sub-pulse generating means 3 is generated at regular intervals within the cycle of the driving pulse.

[0024]

The time counting means 1 counts the time calculated by the time counting time calculating means 2. The clocking time calculation means 2 is short when the difference between the indicated position to be indicated by the hands and the current position indicated by the hands at each time measured by the clocking means 1 is short, and when the difference is small, Calculate long time.

The sub-pulse generating means 3 generates M sub-pulses within the cycle of the drive pulse calculated by the time counting means 2 and drives the stepping motor. The drive pulse determination means 4 determines whether the drive pulse changes from 0 to 1 at the start of the cycle or from 1 to 0.

When it is determined that the driving pulse changes from 0 to 1 at the start of the cycle, the duty ratio changing means 5 gradually increases the duty ratio of the pulse generated by the sub-pulse generating means 3 so that the driving pulse changes from 1 to 0. , The duty ratio of the sub-pulse is gradually reduced.

Further, M generated by the sub-pulse generating means 3
The sub-pulses are generated at equal intervals within the period of the driving pulse, and the duty ratio of the last sub-pulse to be changed by the duty changing means 5 is set to 100% when the driving pulse changes from 0 to 1, and from 1 to 0. When it changes to 0%.

The sub-pulses generated by the sub-pulse generating means 3 are generated at regular intervals within the period of the driving pulse. As described above, the calculation of the difference between the indicated position to be indicated by the pointer and the current position indicated by the current pointer is short when the previously calculated difference is large, and long when the difference is small. After a time, the driving pulse is sent to the step motor after the calculated time,
If the drive pulse rises at the start of the cycle of the drive pulse, the duty ratio of the M sub-pulses generated within the cycle is gradually increased, and if the drive pulse falls, the duty ratio of the M sub-pulses is gradually reduced. As described above, the stepping motor is driven, so that sudden rising and falling driving is alleviated, and vibration rotation due to inertia is eliminated,
The movement of the pointer is smooth and the response is good, and the pointer can be moved smoothly.

The M sub-pulses are generated at regular intervals within the cycle of the driving pulse, and the duty ratio of the last sub-pulse is set to 100% when the driving pulse rises, and to 0% when the driving pulse falls. Since the duty ratio of the sub-pulse is changed to be as small as possible, the movement of the pointer can be made smooth.

Further, since the generation of the sub-pulses is performed at a constant time interval within the cycle of the driving pulse, the hands can be moved smoothly without requiring high-speed processing.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a block diagram of an embodiment of the present invention, and FIGS. 3 and 4 are operation flowcharts of the embodiment. In FIG.
10 is a step motor, 11 is a scale, 12 is a pointer,
13 is a current position detecting unit, 14 is an indicated position calculating unit, 15 is a clock time calculating unit, 16 is a clock unit, 17 is a driving pulse determining unit, 18 is a sub-pulse generating unit, 19 is a duty ratio changing unit, and 20 is a driving pulse. Sending units, 21 to 23 are time counters, 24 is a counter, and 26 to 28 are interfaces (I
/ O) and 29 are processors (CPU) that perform processing.

The embodiment shown in FIG. 2 shows an example in which the I / O 26 displays the speed with the hands 12 based on a signal from a travel sensor that sends out a pulse every time the vehicle travels a unit distance. First, the operation of the designated position calculation unit 14 will be described with reference to FIG.

The operation of the designated position calculating section 14 is started by an interrupt process every time a running pulse is input from the I / O 26. In step S31, a difference between the time when the pulse was input from the I / O 26 last time and the time when the pulse was input this time is calculated.

[0034] In the process _{S32, θ M = K B /} t ··· (4) However, K _B calculates the theta _M performs an operation consisting constant.

That is, in step S32, the speed is calculated from the pulse interval input from the I / O 26, and the rotation angle θ _M of the pointer 12 on the scale 11 corresponding to the calculated speed is calculated. In step S33, to end the recording and processing in a memory (not shown) the indication position theta _M calculated in the processing S32.

As described above, the designated position calculator 14 calculates a new designated position each time a pulse is input from the travel sensor and updates the record. Next, the operation of the embodiment will be described with reference to FIGS. In the processing S1, the clock unit 1
Step 6 determines whether the count value of the time counter ( _TP ) 21 is 0 and waits until the count value becomes 0.

That is, the time counter (T _P ) 21
Set time T _P calculated in step S5 to be described later, detects the time T _P is operated as a down counter. In process S2, the counted time calculating unit 15, an instruction position calculating section 14 reads the indication position theta _M that records to calculate, also pointer 12 the current position theta _P currently indicated current position detecting section 13 Then, the difference θ is calculated by reading through the I / O 27 and performing the following calculation: θ = θ _M −θ _P (5)

In step S3, the time counting unit 15 determines whether or not the difference θ calculated in step S2 is 0. If the determination is YES, the process proceeds to step S4 where the time counter (T
To set the measured time T ₁ to _P) 21. The value T ₁ will be described later. In process S5, the counting time calculating unit _{15, T P = | K A /} θ | + K C ··· (6) However, K _A and K _C is measured time by performing a calculation made constant (period of the drive pulse) calculating a T _P, to start counting by setting the T _P time counter (T _P) 21 proceeds to the processing S6 (FIG. 8 (a)).

In the process S7, the sub-pulse generator 18 calculates the sub-pulse period T _S by performing an operation of T _S = T _P / M (7) (FIGS. 8B and 8C). . In the process S8, the drive pulse determination unit 17 determines the phase φ _n for transmitting the drive pulse.

That is, as described with reference to FIG.
For example, when the difference θ calculated in step S2 is positive, the step motor is rotated clockwise, and the current state is 90 ° (φ1 = 0, φ2 = 1, φ3 =
0, φ4 = 0) and then to 135 °, φ1 = 0, φ
It is necessary to set 2 = 1, φ3 = 1, φ4 = 0.

[0041] determines the next phase phi _n for sending a drive pulse from the rotation direction and the current state of step S8 step motor. In the processing S9, the sub-pulse generation unit 18 clears the counter [M] 24 to 0, proceeds to the processing S10, increments the count value of the counter [M] 24 by 1, and proceeds to the processing S11 to execute the time counter (T _S ) 22. Is set to the period T _{S of} the sub-pulse calculated in the process S7, and time measurement is started.

In step S12, the duty ratio changing unit 18
Is however time counter (T _D) 23 to T _D = (T _S / M) × [M] (8), the T _D which performs the calculation made count value of [M] Counter [M] Set to start timing.

In step S13, the drive pulse determination unit 17
Determines whether the drive pulse transmission phase φ _n determined in step S8 changes from 0 to 1 at the start of the cycle or changes from 1 to 0. Drive pulse is 0 to 1 at start of cycle
The process shifts to step S14 for the phase that changes to, and shifts to process S19 for the phase where the drive pulse changes from 1 to 0 at the end of the cycle.

In step S14, the sub-pulse generator 18
Causes the stepping motor 10 to output 1 through the I / O 28 from the drive pulse sending unit 20. In the processing S15, the sub-pulse generation unit 18 determines whether or not the time counter (T _D ) 23 set and clocked in the processing S12 has completed the clocking. If the clocking has not been completed, the sub-pulse generating unit 18 proceeds to the processing S14. The process then proceeds to output 1 to the step motor. If the time measurement is completed, the process proceeds to step S16 to determine whether or not the count value of the counter [M] 25 is M. If the determination is NO, the process proceeds to step S17. Then, 0 is output to the step motor.

In step S18, the sub-pulse generator 18
Determines whether or not the time counter (T _S ) 22 set and counted in the processing S11 has completed the time measurement. If the time measurement has not been completed, the process waits until the measurement is completed. The process proceeds to S10 to generate the next sub-pulse.

That is, as shown in FIG.
At S11 and S18, the period T of the sub-pulse_SAnd also
When the sub-pulse sends 1 in steps S12 and S15
Interval T _DIs generated, and the set value of the process S12 is changed.
The duty ratio of the sub-pulse is gradually increased.

Steps S19 to S22 are sub-pulse generation processing when the drive pulse corresponding to FIG. 8C changes from 1 to 0. In step S19, 0 is output to the step motor, and in step S22, 1 is output. In the process S23, when it is determined in the processes S16 and S21 that the current sub-pulse is the last sub-pulse, the sub-pulse generator 18 holds 1 or 0 which is currently sent to the step motor, and proceeds to the process S1 to move the next pointer. To start.

As described above, the designated position θ _M and the current position θ
_When the difference θ from _P is large, the time to be measured by the timing unit is shortened, and when θ is small, the time is increased and the driving pulse is transmitted to obtain a smooth and responsive characteristic. . The reason for determining whether or not | θ | = 0 in the process S3 is that when the driving pulse is transmitted when | θ | = 0, the position indicated by the pointer 12 has a larger error than the position currently indicated. made for the delivery of driving pulses is stopped, so that re determined to T ₁ seconds.

Although the value T ₁ can be set arbitrarily, by setting T ₁ small, the designated position calculation unit 1
The pointing position newly calculated in step 4 is changed and the difference θ
, The pointer can be immediately moved to the designated position to improve responsiveness. If the difference θ calculated by the equation (5) and the unit angle θ _{0 at} which the pointer rotates by driving the step motor are not integers, the determination in the processing S3 is made |
θ | <θ _0/2 and it should be.

[0050] Also, the operation when the indication position theta _M has changed suddenly increased, the rotation speed d [theta] _P / dt of the current position theta _P is _{dθ P / dt = θ 0 /} T S = | (θ M -θ P) θ ₀ / K _A | (9), and solving the differential equation of Expression (9), θ _P = θ _M (1−exp [−θ ₀ t / K _A ]) (10) Becomes

That is, as shown by the dotted line in FIG.
_P moves exponentially smoothly and quickly to θ _M. In addition, since the step motor is driven by the sub-pulse whose duty ratio has changed, the motor rotates smoothly as shown by the dotted line in FIG.

Next, referring to FIGS. 6 and 7, FIG.
The operation of the embodiment corresponding to (D) will be described. The operations of FIGS. 6 and 7 correspond to the processing S7, S7 described in FIGS.
Except for S11 and S12, the same operation is performed.

In step S7 ', which replaces step S7, the sub-pulse generator 18 calculates the number M _A of sub-pulses to be driven by performing an operation of M _A = T _P / T _C (11). Note that T _C is the period of the sub-pulse, and is set to a value sufficiently smaller than the operation time of the step motor.

In step S11 ', which changes to step S11, the time
Counter (T_S) Time measurement T at 22 _CSet the time
To start. In step S12 ', which changes to step S12,
Counter (T_D), T_D= (T_C/ M) × [M] (12)_DSet the time and start
You.

By performing the operation as described above, a driving sub-pulse as shown in FIG. 8D is generated, and the step motor is smoothly rotated.

[0056]

As described above, according to the present invention, the following effects can be obtained. The difference between the indicated position to be indicated by the pointer and the current position indicated by the current pointer is calculated to be short when the previously calculated difference is large, and calculated after a long time when the difference is small, A drive pulse is sent to the step motor after the calculated time, and if the drive pulse rises at the start of the cycle of the drive pulse, M generated within the cycle is generated.
The step motor is driven by gradually increasing the duty ratio of the sub-pulses, and gradually decreasing the duty ratio of the M sub-pulses when the driving pulse falls, so that the rising and falling drive is sharp. Is reduced, vibration and rotation due to inertia are eliminated, and the movement of the pointer is smooth and responsive, so that the pointer can be moved smoothly.

Further, M sub-pulses are generated at regular intervals within the cycle of the driving pulse, and the duty ratio of the last sub-pulse is set to 100% when the driving pulse rises, and to 0% when the driving pulse falls. Since the duty ratio of the sub-pulse is changed to be as small as possible, the movement of the pointer can be made smooth.

Further, since the generation of the sub-pulses is performed at fixed time intervals within the cycle of the driving pulse, the hands can be moved smoothly without requiring high-speed processing.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an operation flowchart of the embodiment.

FIG. 4 is an operation flowchart of the embodiment.

FIG. 5 is an operation flowchart of the embodiment.

FIG. 6 is an operation flowchart of another embodiment.

FIG. 7 is an operation flowchart of another embodiment.

FIG. 8 is a diagram for explaining the principle of operation of the present invention for eliminating vibration of the pointer.

FIG. 9 is a diagram illustrating driving of a step motor.

FIG. 10 is an operation explanatory diagram of a conventional example.

FIG. 11 is a diagram illustrating movement of a pointer in a conventional example.

FIG. 12 is a diagram illustrating movement of a pointer in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 clocking means 2 clocking time calculating means 3 sub-pulse generating means 4 driving pulse determining means 5 duty ratio changing means 10 step motor 11 scale 12 pointer 13 current position detecting section 14 pointing position calculating section 15 clocking time calculating section 16 clocking section 17 driving pulse Judgment unit 18 Sub-pulse generation unit 19 Duty ratio change unit 20 Drive pulse transmission unit 21-23 Time counter 24 Counter 26-28 Interface (I / O) 29 Processor (CPU)

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-104221 (JP, A) Patent 2705873 (JP, B2) Japanese Patent Publication No. 5-14206 (JP, B2) Japanese Utility Model Publication No. 5-45977 (JP, A) Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01D 13/22 101 G01D 7/00 G01P 3/42

Claims (3)

(57) [Claims] 1. A hand-held display device in which a display pointer is driven by a stepping motor, a timer means for timing a set time, and an instruction for instructing the display pointer every time the timer means measures time. When the difference between the position and the current position indicated by the current display pointer is large, the time is short, and when the difference is small, a long time is calculated and set in the timer. Sub-pulse generating means for generating M sub-pulses within the cycle of the drive pulse calculated by the calculation means to drive the step motor; and wherein the drive pulse changes from 0 to 1 at the start of the cycle or from 1 to 0 A driving pulse judging means for judging whether or not the driving pulse changes, and a sub-pulse generating means for generating when the driving pulse judging means judges that the driving pulse changes from 0 to 1 at the start of a cycle. Gradually large west of the duty ratio of the pulse,
A needle type display device comprising: a duty ratio changing unit for gradually reducing a duty ratio of a sub-pulse when it is determined that the duty ratio changes from 1 to 0. 2. The method according to claim 1, wherein the M sub-pulses generated by the sub-pulse generating means are generated at equal intervals within the cycle of the driving pulse, and the duty ratio of the last sub-pulse to be changed by the duty ratio changing means is set to be smaller than 0. 2. The needle type display device according to claim 1, wherein 100% is set when it changes to 1, and 0% when it changes from 1 to 0. 3. The needle-type display device according to claim 1, wherein the sub-pulse generated by the sub-pulse generating means is generated at regular intervals within a cycle of the driving pulse.