JPH08152337A - Pointer type indicator - Google Patents

Abstract

PURPOSE: To provide a pointer type indicator in which the pointer is improved to move smoothly. CONSTITUTION: The pointer type indicator having a pointer being driven through a stepping motor comprises means 1 for measuring a set time, means 2 for setting the means 1 with a short time being calculated if the difference between a designated position and a current position is large every time when the means 1 measures a time, and means 3 for generating M subpulses during a calculated period of driving pulse to drive the stepping motor. The pointer type indicator further comprises means 4 for deciding whether the driving pulse makes a transition from 0 to 1 or from 1 to 0 at the time of starting the period, and means 5 for increasing the duty ratio of subpulse gradually when the driving pulse makes a transition from 0 to 1 otherwise decreasing the duty ratio gradually.

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. 9A shows a four-phase stepping motor 10.
And includes a rotor 10a and a stator 10b. The rotor 10a is composed of a magnet, and a display pointer is attached to its rotating shaft via a gear.

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

Hereinafter, as shown in FIG. 9B, φ1 to φ4
The rotor 10a is sequentially rotated by applying a pulse to
Rotate by 5 °. The motor 10 rotates 45 ° each time a drive pulse is input, but the display pointer is geared down by a gear (not shown) to rotate by θ ₀ degrees.

In the conventional needle type display device, as shown in FIG. 10, N = (θ _M from the instructed position θ _M to be instructed at constant time intervals T and the current position θ _P currently instructed by the pointer. −θ _P ) / θ ₀ (1) The drive pulse N is calculated by performing the following calculation.

When the driving pulse number N is calculated, FIG.
As shown in (A), N driving pulses are transmitted at time intervals T _A. That is, when the pulse motor is rotated clockwise now, the current pulse motor is set to 0 in FIG. 9 (B).
Assuming that the position is °, φ1 = at time t ₁ .
The driving pulse of 1, φ2 = 1 and the driving pulse of φ1 = 0, φ2 = 1 are transmitted at t ₂ after the time T _A to rotate the step motor.

Therefore, the deflection of the pointer does not fluctuate from the Nth pulse is transmitted until the 1st pulse calculated in the next cycle T is transmitted, and the pointer changes stepwise. It wasn't smooth. A method for smoothing the deflection of the pointer is described in Japanese Utility Model Laid-Open No. 64-6556.

This method, as shown in FIG.
The pulse transmission interval for transmitting N pulses within the period T is T
/ N, and the transmission of the first pulse is delayed by the time T / 2N. In this way, the movement of the pointer becomes smooth by controlling the pulse transmission start time and the pulse transmission time interval.

Here, if 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 , then T / N ≧ T _A (2) Since the first pulse is delayed by averaging, T ≧ / 2NT _A (3) from FIG. 10 (B) and equation (2) Therefore, the value of T can be smaller than a certain numerical value. Recognize.

[0010]

In the needle type display device driven by the step motor, the drive pulse is sent at a time interval longer than the minimum time that the step operation of the step motor can follow, but the sending timing at that time. Is required to have good responsiveness to changes in the input signal and to have a smooth response.

The indicated angle θ _{M in} FIG. 11 shows an example of the case where the vehicle gradually increases in speed and accelerates until it reaches a constant speed. The solid line indicates the minimum time interval that the step operation of the step motor can follow T _A, and the period T shown in FIG. 10 is T = 6 T _A and T = 12 T _A. 3 shows the movement of the needle when it is operated by the method described in.

Although smoothness is improved by this method,
Since the difference is calculated for each cycle T, a response delay occurs in the entire region. Since the pulse transmission interval is changed for each cycle T, a rapid change occurs as shown in A of FIG. The smoothness is lost, the cycle T is further deteriorated when it is increased, the cycle T cannot be smaller than a certain value as described above, and the input signal changes variously. There are problems such as setting is quite difficult.

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

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

It is an object of the present invention to provide a needle type display device improved so that the movement of the pointer is smooth and the response is smooth.

[0016]

Means adopted by the present invention for solving the above-mentioned problems will be described. First, before explaining the means solved by the invention, the principle of eliminating the vibration of the pointer generated at the rise and fall of the drive pulse of the present invention is shown in FIG.
Will be described with reference to.

FIG. 8 (A) shows each phase φ described in FIG. 9 (B).
_The drive pulse applied to _n is shown. The drive pulse is composed of a drive pulse a rising from 0 to 1, a drive pulse b holding 1 and a drive pulse c falling from 1 to 0.

The reason why the pointer 12 vibrates is that the drive 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.

In the case of the trailing edge, as shown in FIG. 8C, M sub-pulses are generated within the period T _{P of the} drive pulse, and the duty ratio thereof is gradually reduced. By doing so, the driving 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 operating time of the step motor. In addition, as a method for relaxing the driving of the step motor, in FIGS. 8B and 8C, M sub-pulses are generated within the period T _{P of the} driving pulse, but in FIG. 8D, the driving pulse is generated. Cycle T
Within _P , time T _C less than the drive time of the step motor
Each time a sub-pulse is generated and its duty ratio is changed to smooth the movement of the pointer.

The means adopted by the present invention will be described below with reference to FIG. FIG. 1 is a basic configuration diagram of the present invention. In the needle type display device that drives the display pointer with a step motor,
There is a large difference between the time measuring means 1 for measuring the set time, and the indicated position where the indication pointer tries to indicate every time the time measuring means 1 measures the time and the current position indicated by the current indication pointer. 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 measuring means 1, and M times are calculated in the period of the drive pulse calculated by the time measuring time calculating means 2. A sub-pulse generating means 3 for generating a sub-pulse to drive the step motor, a drive pulse determining means 4 for determining whether the drive pulse changes from 0 to 1 or from 1 at the start of a cycle, When the drive pulse determination 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 generation means 3 is gradually increased to 1
And a duty ratio changing means 5 that gradually reduces the duty ratio of the sub-pulse when it is determined that the duty ratio of the sub-pulse changes.

The duty ratio of the last subpulse generated by the subpulse generating means 3 is generated at equal intervals within the period of the drive pulse, and the duty ratio of the last subpulse is changed by the drive pulse. 100% when changing from 0 to 1 and 0% when changing from 1 to 0
To

Further, the sub-pulses generated by the sub-pulse generating means 3 are generated at regular intervals within the period of the drive pulse.

[0024]

The time measuring means 1 measures the time calculated by the time measuring time calculating means 2. The timekeeping time calculation means 2 is short when the difference between the pointed position to be pointed by the pointer and the current position pointed by the pointer is short at each time measured by the timekeeping means 1, and short when the difference is small. Calculate a long time.

The sub-pulse generating means 3 drives the step motor by generating M sub-pulses within the period of the drive pulse calculated by the clocking time calculating means 2. The drive pulse determination means 4 determines whether the drive pulse changes from 0 to 1 at the start of a cycle or from 1 to 0.

When it is determined that the drive 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 drive pulse is 0 or more. When it is determined to change to, the duty ratio of the sub-pulse is gradually reduced.

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

Further, the sub-pulses generated by the sub-pulse generator 3 are generated within the cycle of the drive pulse at regular intervals. As described above, the difference between the position pointed by the pointer and the current position pointed by the pointer is calculated short when the previously calculated difference is large and long when the difference is small. It is calculated after the time, and the drive pulse is sent to the step motor after the calculated time.
When the drive pulse rises at the start of the period of the drive pulse, the duty ratio of M sub-pulses generated within the period is gradually increased, and when the drive pulse falls, the duty ratio of M sub-pulses is gradually reduced. Since the step motor is driven in this way, sudden rising and falling drives are alleviated, and vibration rotation due to inertia disappears.
The pointer can be moved smoothly, has good responsiveness, and can be moved smoothly.

Further, the M sub-pulses are generated at equal intervals within the period of the drive pulse, and the duty ratio of the last sub-pulse is set to 100% when the drive pulse is rising, and is set to 0% when it is falling. The duty ratio of the sub-pulse is changed so that the pointer can be moved smoothly.

Further, since the sub-pulses are generated at a constant time interval within the period of the drive pulse, the pointer can be moved smoothly without requiring high-speed processing.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 is a block diagram of an embodiment of the present invention, and FIGS. 3 to 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 a designated position calculating unit, 15 is a time measuring unit, 16 is a time measuring unit, 17 is a drive pulse determining unit, 18 is a sub-pulse generating unit, 19 is a duty ratio changing unit, and 20 is a drive pulse. Sending section, 21 to 23 are time counters, 24 is a counter, 26 to 28 are interfaces (I
/ O) and 29 are processors (CPU) that perform processing.

In the embodiment shown in FIG. 2, the speed is displayed on the I / O 26 by the pointer 12 based on a signal from a traveling sensor which outputs a pulse each 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 calculation unit 14 is started by an interrupt process every time a traveling pulse is input from the I / O 26. In step S31, a difference between the time when the pulse is input from the previous I / O 26 and the time when the pulse is 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 process S33, the designated position θ _M calculated in process S32 is recorded in a memory (not shown), and the process ends.

As described above, the designated position calculation unit 14 calculates a new designated position and updates the record each time a pulse is input from the running sensor. Next, the operation of the embodiment will be described with reference to FIGS. In the process S1, the timer unit 1
6 determines whether or not 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 is
The time T _P calculated in the process S5 described later is set, and the time T _P is detected by operating as a down counter. In the process S2, the clocked time calculation unit 15 reads the designated position θ _M calculated and recorded by the designated position calculation unit 14, and the current position θ _P currently designated by the hands 12 is detected by the current position detection unit 13. Then, the difference is calculated by reading through the I / O 27 and performing the calculation of θ = θ _M −θ _P (5).

In the process S3, the clocked time calculation unit 15 determines whether or not the difference θ calculated in the process S2 is 0. If the determination is YES, the process proceeds to the process S4 and the time counter (T
_P ) 21 is set to time T ₁ . The value T ₁ will be described later. In the process S5, the clocking time calculation unit 15 calculates T _P = | K _A / θ | + K _C (6) where K _A and K _C are constants and the clocking time (driving pulse cycle) 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 step S7, the sub-pulse generator 18 calculates the sub-pulse period T _S by performing the calculation T _S = T _P / M (7) (FIGS. 8B and 8C). . In step S8, the drive pulse determination unit 17 determines the phase φ _n that sends the drive pulse.

That is, as described with reference to FIG.
For example, when the difference θ calculated in the process S2 is positive, the step motor is rotated clockwise, and the current state is 90 ° (φ1 = 0, φ2 = 1, φ3 = in FIG. 9B).
0, φ4 = 0), and next 135 °, φ1 = 0, φ
It is necessary to set 2 = 1, φ3 = 1, and φ4 = 0.

In step S8, the phase φ _n to which the drive pulse is sent next is determined based on the rotation direction of the step motor and the current state. In process S9, the sub-pulse generator 18 clears the counter [M] 24 to 0, moves to process S10, increments the count value of the counter [M] 24 by 1, and moves to process S11 to move to the time counter (T _S ) 22. Is set to the period T _{S of} the sub-pulse calculated in step S7 and the time counting is started.

In step S12, the duty ratio changing unit 18
Is T _D = (T _S / M) × [M] (8) in the time counter (T _D ) 23, where [M] is T _D calculated as the count value of the counter [M]. Set and 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 or from 1 to 0 at the start point of the cycle. Drive pulse is 0 to 1 at the start of the cycle
The process shifts to the step S14 for the phase changing to, and to the process S19 for the phase where the drive pulse changes from 1 to 0 at the end point of the cycle.

In step S14, the sub-pulse generator 18
Causes the drive pulse transmitter 20 to output 1 to the step motor 10 via the I / O 28. In process S15, the sub-pulse generation unit 18 determines whether or not the time counter (T _D ) 23 set in process S12 and measuring time has ended, and when the time measurement has not ended, the process proceeds to process S14. Then, the step motor continues to output 1 and when 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. After that, 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 that has been set in step S11 and has timed has finished counting, and if it has not finished, it waits until it finishes, and if it has finished, the process Moving to S10, the next sub-pulse is generated.

That is, as shown in FIG.
Subpulse period T in S11 and S18_SAlso,
When the sub pulse sends out 1 in processing 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 process S23, the sub-pulse generation unit 18 holds 1 or 0 currently sent to the step motor when it is determined to be the last sub-pulse in processes S16 and 21, and moves to 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 with _P is large, the time to be kept in the timekeeping section is shortened, and when θ is small, the timed time is lengthened and the drive pulse is sent to obtain smooth and responsive characteristics. . It should be noted that the reason for determining whether or not | θ | = 0 in the process S3 is that the position indicated by the pointer 12 when the drive pulse is transmitted when | θ | = 0 has a larger error than the position currently indicated. Therefore, the transmission of the drive pulse is stopped and the judgment is made again at T ₁ seconds.

The value T ₁ can be set arbitrarily, but by setting T ₁ small, the pointing position calculation unit 1
The newly calculated pointed position in 4 changes and the difference θ
Even if occurs, it is possible to immediately move the pointer to the pointing position and improve the 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 process S3 is |
θ | <θ _0/2 and it should be.

When the designated position θ _M suddenly changes greatly, the rotational speed dθ _P / dt of the current position θ _P is dθ _P / dt = θ ₀ / T _S = | (θ _M −θ _P ) θ ₀ / K _A | (9) and solving the differential equation (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 rapidly to θ _M. Further, since the step motor is driven by the sub-pulse whose duty ratio is changed, the step motor rotates smoothly as shown by the dotted line in FIG.

Next, referring to FIG. 6 and FIG.
The operation of the embodiment corresponding to (D) will be described. The operations of FIGS. 6 and 7 are the same as those of steps S7 and S described with reference to FIGS.
The same operation is performed except for 11 and S12.

In the process S7 'which is replaced with the process 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 operating time of the step motor.

In the process S11 'which is changed to the process S11, the time is
Counter (T_S) 22 time T _CSet and clock
To start. In the process S12 ′ which is changed to the process S12,
Counter (T_D), T_D= (T_C/M)×[M]...(12)_DTo set and start timing
It

By performing the operation as described above, the drive sub-pulse as shown in FIG. 8 (D) is generated to smoothly rotate the step motor.

[0056]

As described above, according to the present invention, the following effects can be obtained. The difference between the position indicated by the pointer and the current position indicated by the pointer is calculated shortly when the previously calculated difference is large, and after a long time when the difference is small, Further, the drive pulse is sent to the step motor after the calculated time, and when the drive pulse rises at the start of the cycle of the drive pulse, M generated within the cycle is generated.
The duty ratio of each sub-pulse is gradually increased, and when the drive pulse falls, the duty ratio of M sub-pulses is gradually reduced to drive the step motor. Is alleviated, vibration and rotation due to inertia disappears, the pointer moves smoothly, and the responsiveness is good, so that the pointer can be moved smoothly.

Further, the M sub-pulses are generated at equal intervals within the period of the drive pulse, and the duty ratio of the last sub-pulse is set to 100% when the drive pulse is rising, and is set to 0% when it is falling. The duty ratio of the sub-pulse is changed so that the pointer can be moved smoothly.

Further, since the sub-pulses are generated at a constant time interval within the period of the drive pulse, the pointer can be moved smoothly without requiring high-speed processing.

[Brief description of 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 same 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 operation principle of eliminating the vibration of the pointer of the present invention.

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]

 1 time measuring means 2 time measuring 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 indicated position calculating section 15 time measuring time calculating section 16 time measuring 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)

Claims (3)

[Claims] 1. A hand-type display device in which a display pointer is driven by a step motor, and a timing means for timing a set time, and an instruction for instructing the display pointer each time the timing means measures the time. When the difference between the position and the current position indicated by the current display pointer is large, it is short, and when the difference is small, it calculates a long time and sets it in the time measuring means. A sub-pulse generating means for driving the step motor by generating M sub-pulses within the cycle of the drive pulse calculated by the calculating means; and the drive pulse changing from 0 to 1 at the start of the cycle or from 1 to 0. Drive pulse determining means for determining whether the drive pulse changes, and the sub pulse generating means for generating when the drive pulse determining means determines that the drive 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 that gradually reduces the duty ratio of the sub-pulse when it is determined that the duty ratio changes from 1 to 0. 2. The duty ratio of the last sub-pulse, which is generated by the sub-pulse generating means, is generated at equal intervals within the cycle of the drive pulse, and is changed by the duty ratio changing means when the drive pulse is 0 or less. The needle type display device according to claim 1, wherein 100% is set when changing to 1, and 0% is set when changing from 1 to 0. 3. The needle type display device according to claim 1, wherein the sub-pulses generated by the sub-pulse generating means are generated at regular intervals within a period of the drive pulse.