JPH11184528A - Controller for moving object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the miniaturization of a device and the reduction of noises while avoiding the influence of the dispersion of a braking distance or a secular change when performing the stop control of a moving object such as a carriage on a printer. SOLUTION: Two phase pulses with a phase shift of 90 deg. are outputted from an encoder 10 with the move of a carriage 9, and corresponding to these pulses, the moving direction, current position and moving speed of the carriage 9 are respectively detected by a direction detector 13, a position detector 14 and a speed detector 15. Based on these detected results, a microcomputer 1 controls a DC motor 8 as a driving source of the carriage 9 through a driving circuit 7 and performs the stop control of the carriage 9. In that case, the microcomputer 1 controls the forward driving, backward driving and braking of the DC motor 8 based on the information of the movable range of the carriage 9 from the detected information of the respective detectors 13-15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a moving body such as a carriage on which a print head is mounted.

[0002]

2. Description of the Related Art Conventionally, for example, in a serial printer, a DC (direct current) motor is used as a driving means of a movable body such as a carriage having a print head mounted thereon, and an encoder is used as a position detecting means. In addition, speed control and position control are performed. At that time, when stopping the moving body such as the carriage from the moving state,
Use the braking effect of the motor itself obtained by shorting the motor drive terminal, or forcibly reduce the speed until it stops by driving the motor in the opposite direction to the previous drive direction The method is taken.

[0003]

However, there are the following problems in the conventional control of a moving body as described above.

[0004] When the motor is stopped by using the braking effect of the motor itself, the braking distance varies among individual devices and the same device changes over time. It is necessary to sufficiently consider the above-mentioned variation in addition to a wide movable range, and to make the width with a margin. This is a factor that hinders downsizing of the device.

[0005] When the vehicle is forcibly stopped by the reverse rotation drive, there is an advantage that the distance required for the stop is shorter than the case where the braking effect is used, but on the other hand, noise is easily generated due to sudden deceleration.

The present invention has been made in view of the above-mentioned problems, and it is possible to avoid the influence of variations in braking distance and aging, and to reduce the size and noise of equipment. The purpose of the present invention is to obtain a control device for a mobile object.

[0007]

A control device for a mobile unit according to the present invention is configured as follows.

(1) Direction detecting means for detecting the moving direction of the moving body, speed detecting means for detecting the moving speed of the moving body, position detecting means for detecting the current position of the moving body, and a driving source for the moving body A driving circuit having a control function of forward rotation, reverse rotation and braking of the motor, and control means for controlling stop of the moving body via the driving circuit. Stop control is performed based on the detection information of the means and the information on the movable range of the moving body.

(2) In the configuration of the above (1), there is provided an encoder for generating a two-phase pulse whose phase is shifted by 90 degrees with the movement of the moving body, and the direction detecting means, the speed detecting means and the position detecting means Each detection is performed by a pulse from the encoder.

(3) In the configuration of (1) or (2), the moving body is a carriage on which a print head in a printing apparatus is mounted.

(4) In any one of the above constitutions (1) to (3), the control means determines a reference braking distance at a reference speed based on a relationship between a moving speed of the moving body at a braking start position and a stopping distance from the position. Is calculated based on the reference speed, the reference braking distance, and the current speed.Depending on whether the position far from the current position by the current braking distance in the moving direction is within the movable range of the moving object. Stop control is performed.

(5) In the above configuration (4), if the position farther from the current position by the current braking distance in the moving direction does not exceed the left end or the right end of the moving range of the moving body, the target stop position is reached. The motor is decelerated and stopped by the braking effect of the motor itself by short-circuiting the motor terminals.

(6) In the above configuration (4), if the position farther from the current position by the current braking distance in the moving direction is equal to or exceeds the left end or the right end of the moving range of the moving body, the target stop start position is set. Stop control by reverse rotation of the motor is performed even if it has not reached.

(7) In the configuration of the above (6), when the current speed is lower than the speed at the start of the stop control and higher than the initial braking end speed, the speed is reduced by utilizing the braking effect of the motor itself by short-circuiting the motor terminals. I tried to make it.

(8) In the configuration of (6), when the current speed is equal to or lower than the initial braking end speed and equal to or higher than the reverse driving end speed, the moving direction is opposite to the moving direction by the reverse driving force based on the current speed and the minimum reverse driving force. To be driven.

(9) In the above configuration (6), when the current speed is equal to or lower than the reverse drive end speed, the braking mode is set.

(10) In the configuration of (6) above, when the current speed is in the stop state, the difference between the stop distance, which is the difference between the stop position and the reverse rotation start position, and the prescribed reference stop distance is compared with an allowable value. And stop control is performed.

(11) In the configuration of (10), if the difference between the stopping distances is equal to or smaller than the allowable value, the control is terminated.

(12) In the configuration of the above (10), if the difference between the stopping distances is larger than the allowable value and the stopping distance is larger than the standard stopping distance, the reverse driving force is increased and the control is ended.

(13) In the configuration of the above (10), if the difference between the stopping distances is larger than the allowable value and the stopping distance is smaller than the reference stopping distance, the reverse driving force is reduced to end the control.

(14) In the configuration of (12), the reverse driving force is increased in accordance with the set reverse rotation increase / decrease section number.

(15) In the configuration of the above (13), the reverse drive force is reduced according to the set reverse drive increase / decrease section number.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a system configuration of a printing apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a microcomputer (control means) which is a control entity of the present system.
Are connected to a ROM 2 for storing control software (programs) executed by the CPU and a RAM 3 for temporarily storing control data. In the microcomputer 1,
A computing unit (computing means) 4 for computing control data and an input / output unit 5 having an interface function with an external electric element are built in. Note that the above-described ROM 2 and RAM 3 may also be built in the microcomputer 1.

Reference numeral 6 denotes a non-volatile storage element for storing temporary data or data which is inconvenient when it is lost, and retains data necessary for control even when power is not supplied, and retains the stored contents even when the power is turned off. . 7 is a DC (direct current) having a forward drive function, a reverse drive function, and a braking function for short-circuiting a motor terminal.
In the drive circuit of the motor 8, the DC motor 8 is a drive source of a carriage (moving body) 9 which is a movable member on which a print head is mounted.

Numeral 10 denotes a magnetic or optical encoder for generating two-phase pulses 90 degrees out of phase with the movement of the carriage 9. The magnetic encoder includes a linear member magnetized at regular intervals. The two-phase magnetic detector is out of phase by 90 degrees. One of the members is fixed to the fixed member side of the non-movable main body, and the other member is fixed to the movable member side such as the carriage 9. The optical type is composed of a slit having a shielding part and a transmitting part at regular intervals, and a two-phase photointerrupter with a phase shift of 90 degrees, and one is fixed to a fixed member and the other is a movable member as in the magnetic type. Fixed.

Reference numeral 11 denotes a belt for converting the rotary motion of the DC motor 8 into a linear motion together with the pulley 12, and is passed between the motor shaft of the DC motor 8 and the pulley 12, and the carriage 9 is fixed to the belt 11. To move straight in the horizontal direction. 13 is a direction detector for detecting the moving direction of the carriage 9 from the output signal of the encoder 10, 14 is a position detector for detecting the current position of the carriage 9 from the output signal of the encoder 10, and 15 is from the output signal of the encoder 10. A speed detector for detecting the moving speed of the carriage 9;
Each of these detectors 13 to 15 is constituted by an electric circuit, and each detection output is input to the microcomputer 1.

FIG. 2 is a diagram showing the details of the direction detecting means using the direction detector 13. FIG.
(2) shows the waveform of the encoder signal input to the direction detector 13 and the waveform of the direction signal to be output, and (3) shows the direction determination logic.

In this direction detecting means, a direction judging unit 131 composed of a logic circuit which uses two-phase signals of A-phase and B-phase outputted from the encoder 10 as input signals and uses the moving direction information of the carriage 9 as an output direction signal. prepare. The direction determiner 131 can be constituted only by an electric logic circuit, or can be constituted by a combination of an electric logic circuit and software like a microcomputer. And

[0030]

(Equation 1)

FIG. 3 is a diagram showing details of position detecting means using the position detector 14. (1) is a configuration of the position detector 14, (2) is an encoder signal input to the position detector 14 and The waveform of the direction signal, (3) shows the position detection logic.

In this position detecting means, one of the two A-phase signals outputted from the encoder 10 and the direction signal obtained by the direction detecting means are used as input signals, and the position information of the carriage 9 is used as an output position signal. Pulse counter (Up / Down Counter) 1 comprising a logic circuit
41 is prepared. The counter 141 can be constituted only by an electric logic circuit, or can be constituted by a combination of an electric logic circuit and software like a microcomputer, and a direction signal (encoder signal ↑) = 0. Then, if the addition direction signal (encoder signal ↑) = 1, it is determined that the subtraction is performed.

Here, the "direction signal (encoder signal ↑)" means "the value of the direction signal when the encoder signal rises."

FIG. 4 is a diagram showing details of speed detecting means using the speed detector 15. (1) is a configuration of the speed detector 15, and (2) is an encoder signal input to the speed detector 15. The waveform is shown.

In this speed detecting means, a logic circuit is prepared in which one of the two-phase signals output from the encoder 10 is used as an input signal and the speed information of the carriage 9 is used as an output speed signal. The present logic circuit can be constituted only by an electrical logic circuit, or can be realized by combining an electrical logic circuit and software such as a microcomputer.
Here, a period counter 151 that inputs an encoder signal and a clock and outputs a period signal and a divider 152 that inputs the period signal and a reference period signal and outputs a speed signal are combined.

(Operation of Embodiment) Next, a specific control example will be described. In this embodiment, the microcomputer 1 is used to control each hardware by software, and the drive circuit 7 is controlled in accordance with the output signals of the respective detectors 13 to 15 to stop the carriage 9. Control is performed.

The microcomputer 1 first measures the initial braking distance as a preparatory work for the stop control operation. This means that, as shown in FIG. 5, the carriage 9 is started to move at a certain fixed power, braking is started during the movement, and the moving speed v0 at the braking start position and the difference d0 between the braking start position and the stop position are calculated. measure. At this time, in order to improve the measurement accuracy, measurement is repeated n times, and the average value of n times is d
It may be set to 0.

Then, the reference speed is set to V, and the reference braking distance D is calculated by the following equation.

Reference braking distance D = d0 × V / v0 The above-described reference braking distance D is stored in the nonvolatile storage element 6. As described above, the preparation for the stop control is prepared.

Next, the procedure of the stop control will be described with reference to the flowchart of FIG. In this stop control, two types of stop control, a method using a braking effect (referred to as a braking mode) and a method using both the braking effect and the reverse rotation driving (referred to as a reverse rotation mode), are selected and executed.

Step 1 <Movement Start> Increase / decrease section number n of reverse rotation drive is set to 0. Then, the carriage 9 starts moving toward the target stop start position.

Step 2 <Calculation of current braking distance> Using the reference braking distance D, a current braking distance d1 corresponding to the current speed v is obtained by the following equation.

Current braking distance d1 = D × v / V Step 3 <Judgment as to whether or not reverse rotation mode is required> The planned stop position Pstop during braking is compared with the movement limit position (left end Pmin, right end Pmax) in the mechanism of the apparatus. (See FIG. 7). And Pmin≪Pstop and Ps
If top≪Pmax, go to step 4. Also, P
If stop @ Pmin or Pmax @ Pstop, go to step 5.

Here, P1≪P2 means that P1 is located to the left of P2.

FIG. 7 shows how the above stop control is selected. Here, as the state of the speed decrease during braking, the case where the speed at the start of braking is v1 and the case where v2 (v1> v
2) shows the case. The braking distance at speed v1 is d1
Indicates the stop position (P) at the time of braking while moving at the speed v1, and the limit of the stop start position that does not touch the left end during the movement at speed v2.

Step 4 <Determining Whether the Current Position Has Reached the Target Stop Start Position> If the current position has reached the target stop start position, the operation proceeds to step 5. If not, return to step 2.

Step 5 <braking mode> Braking is started. Then, the braking is ended.

Step 6 <Determination as to whether or not it is within the initial braking section> If it is within the initial braking section, the process proceeds to step 7. Otherwise, go to step 8.

Step 7 <braking mode> Braking is started. Then, the process returns to Step 6.

Step 8 <Judgment as to whether or not the speed is equal to or higher than the initial braking end speed>
Proceed to. Otherwise, go to step 10.

Step 9 <braking mode> Braking is started. Then, the process returns to Step 6.

Step 10 <Judgment as to whether or not the rotation speed is equal to or higher than the reverse rotation driving end speed>
Otherwise, go to step 12.

Step 11 <reverse rotation mode> The motor is driven in the reverse direction with the drive power calculated by the following equation from the current speed v, the speed weighting coefficient A, and the minimum reverse drive power Xmin. Then, the process returns to Step 10.

Reverse rotation driving power power = A × v + Xmin Otherwise, proceed to step 12.

Step 12 <braking mode> Braking is started. Then, the process proceeds to step S13.

Step 13 <Confirmation of Stop> If it is in the stop state, the process proceeds to step 14. Otherwise, return to step 13.

Step 14 <Inspection of Stopping Accuracy> The difference c between the stopping distance d and the predetermined standard stopping distance D is set to an allowable value C.
Compare with If c ≦ C, the control ends. If c> C, the process proceeds to step 15.

Step 15 <Correction of Reverse Drive Power> The stop distance d is compared with a predetermined standard stop distance D. If d> D and the preset reverse drive increase / decrease section number n = -1 (n: positive number), the speed weighting coefficient A is increased with the standard speed weighting coefficient At as a limit. When the speed weighting coefficient A reaches the standard speed weighting coefficient At, the increase / decrease section number n is set to 0.
Then, the process proceeds to step S16.

Further, d> D and the increase / decrease section number n
If = 0, the minimum reverse drive power Xmin is increased with the maximum reverse drive power Xmax as a limit. Xmi
When n = Xmax is reached, the increase / decrease section number n = 1. Then, the process proceeds to step S16.

Further, d> D and the increase / decrease section number n
If = 1, the speed weighting coefficient A is increased with the maximum speed weighting coefficient Amax as a limit. Then, the process proceeds to step S16.

Further, d <D and the increase / decrease section number n
If = -1, the speed weighting coefficient A is reduced with 0 as a limit. Then, the process proceeds to step S16.

Further, d <D and the increase / decrease section number n
If = 0, the minimum reverse driving power Xm is limited to 0.
decrease in. If Xmin has reached 0, the increase / decrease section number is set to n = -1. Then, the process proceeds to step S16.

Further, d <D and the increase / decrease section number n
If = 1, the speed weighting factor A is reduced with the standard speed weighting factor At as a limit. When the speed weighting coefficient A reaches the standard speed weighting coefficient At, the increase / decrease section number n is set to n = 0. Then, the process proceeds to step S16.

Step 16 <Storage of Correction Value> The increase / decrease section number n, the speed weighting coefficient A, and the minimum reverse drive power Xmin are stored in the nonvolatile storage element 6. Then, the control ends.

When the above procedure is executed, the speed and the driving force change as shown in FIG. Further, the correction result of the driving force is an example as shown in FIG.

FIG. 8 shows the state of the reverse rotation stop control. When the initial braking section has passed from the time of the stop start position, the initial braking end speed is obtained by the forward rotation driving force, and further, the reverse driving force is applied in the moving direction during the reverse rotation driving section, whereby the reverse rotation driving end speed is obtained. After a later braking period, the vehicle stops.

FIG. 9 shows an example of convergence of the reverse rotation stop control. When the vehicle enters the reverse rotation driving section through the initial braking section from the time of the stop start position, a reverse rotation driving force is applied in the moving direction. At this time, the distance to stop varies depending on the required driving.

(Effects of Embodiment) As described above, in this embodiment, it is possible to avoid the influence of variation in braking distance and aging, and it is possible to reduce the size of the device and reduce noise.

That is, in the present embodiment, the stop control by the DC motor 8 employs a method utilizing the braking effect as the main control of the stop control, and also uses a reverse rotation drive when approaching the fixed member. . Therefore, there is an effect of improving the control function that it is possible to avoid contact with the fixed member due to the variation of the braking distance, and also in the method using the reverse drive, the reverse drive power is optimized by using the braking effect together, and Since the execution condition is limited to avoid contact, there is an effect of quieting the operation of the device. At the same time, there is an effect of noise reduction for the operating environment.

Further, in this embodiment, since the present invention is realized only by adding software without adding hardware, it is not limited to a printing apparatus but is widely applied to a device having a mechanism for moving some member by a motor. It has applicable flexibility.

[0071]

As described above, according to the present invention,
The stop control by the motor uses the braking effect as the main method of the stop control, and also uses the reverse rotation drive when approaching the fixed member, so that the contact with the fixed member due to the variation in the braking distance This has the effect of improving the control function that can be avoided. Also, in the method using the reverse drive, the reverse drive power is optimized by using the braking effect, and the execution condition is limited to avoid contact, so that there is an effect of quieting the operation of the device. At the same time, there is an effect of noise reduction for the operating environment.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a system configuration according to an embodiment;

FIG. 2 is an explanatory diagram showing details of a direction detecting unit.

FIG. 3 is an explanatory diagram showing details of a position detecting unit.

FIG. 4 is an explanatory diagram showing details of a speed detecting means.

FIG. 5 is an explanatory diagram showing a state of measurement of an initial braking distance.

FIG. 6 is a flowchart showing a stop control procedure.

FIG. 7 is an explanatory diagram showing a state of selection of stop control.

FIG. 8 is an explanatory diagram showing a state of reverse rotation stop control.

FIG. 9 is an explanatory diagram showing an example of convergence of reverse rotation stop control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microcomputer (control means) 2 ROM 3 RAM 4 Computing unit 5 Input / output unit 6 Nonvolatile storage element 7 Drive circuit 8 DC motor 9 Carriage (moving body) 10 Encoder 11 Belt 12 Pulley 13 Direction detector 14 Position detector 15 Speed detector

Claims (15)

[Claims] 1. A direction detecting means for detecting a moving direction of a moving body, a speed detecting means for detecting a moving speed of the moving body, a position detecting means for detecting a current position of the moving body, and a driving source for the moving body. A motor, a drive circuit having a control function of normal rotation, reverse rotation and braking of the motor, and control means for performing stop control of the moving body via the drive circuit, the control means includes:
A control device for a moving body, wherein the stop control is performed based on detection information of each of the detecting means and information on a movable range of the moving body. 2. An encoder for generating two-phase pulses 90 degrees out of phase with the movement of the moving body, wherein the direction detecting means, the speed detecting means, and the position detecting means detect each by a pulse from the encoder. The control device for a moving body according to claim 1, wherein the control is performed. 3. The control device for a moving body according to claim 1, wherein the moving body is a carriage mounted with a print head in the printing apparatus. 4. The control means calculates a reference braking distance at a reference speed from a relationship between a moving speed of the moving body at a braking start position and a stopping distance from the position, and calculates the reference speed, the reference braking distance, and the current speed. Calculate the current braking distance based on
4. The control device according to claim 1, wherein stop control is performed based on whether a position farther from the current position by the current braking distance in the moving direction is within a movable range of the moving object. 5. When the position farther from the current position by the current braking distance in the moving direction does not exceed the left end or the right end of the moving range of the moving body, the motor itself by short-circuiting the motor terminal after reaching the target stop position. 5. The control device for a moving body according to claim 4, wherein the vehicle is decelerated to a stop by the braking effect of (1). 6. If the position farther from the current position by the current braking distance in the moving direction is equal to or exceeds the left end or the right end of the moving range of the moving body, the motor rotates in the reverse direction even if the target stop start position is not reached. The control device for a moving body according to claim 4, wherein stop control by driving is performed. 7. The method according to claim 6, wherein when the current speed is lower than the speed at the start of the stop control and higher than the initial braking end speed, the motor is decelerated by utilizing the braking effect of the motor itself by short-circuiting the motor terminals. A control device for a moving body according to any one of the preceding claims. 8. When the current speed is equal to or lower than the initial braking end speed and equal to or higher than the reverse drive end speed, the motor is driven in a direction opposite to the moving direction by a reverse drive force based on the current speed and the minimum reverse drive force. Item 7. A control device for a moving object according to Item 6. 9. The control device according to claim 6, wherein the braking mode is set when the current speed is equal to or lower than the reverse rotation end speed. 10. When the current speed is in a stop state, stop control is performed by comparing a difference between a stop distance, which is a difference between a stop position and a reverse rotation start position, and a prescribed reference stop distance with an allowable value. The control device for a moving body according to claim 6, wherein 11. The control apparatus according to claim 10, wherein the control is terminated when the difference between the stopping distances is equal to or less than an allowable value. 12. If the difference between the stop distances is larger than an allowable value and the stop distance is larger than a reference stop distance, the reverse drive force is increased and the control is terminated.
A control device for a moving body according to any one of the preceding claims. 13. The control system according to claim 10, wherein when the difference between the stop distances is larger than an allowable value and the stop distance is smaller than a reference stop distance, the reverse driving force is reduced to end the control.
A control device for a moving body according to any one of the preceding claims. 14. A reverse driving force is increased in accordance with a set reverse drive increase / decrease section number.
3. The control device for a moving body according to 2. 15. The reverse rotation driving force is reduced according to the set reverse rotation increase / decrease section number.
4. The control device for a moving object according to 3.