JP2017070082A - Motor drive controller and drive control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive controller and drive control method, capable of completely stopping a motor at a stable position when a power system has a failure.SOLUTION: A power supply 5 connected with a drive controller 4 drivingly controlling a motor 3 capable of microstep driving is monitored by a voltage monitor 46. When a failure of the power supply 5 is detected, a drive control unit 45 stops microstep driving of the motor 3 by a motor driver 42 and moves the motor 3 to a stable position by electric power stored in a capacitor 43.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a drive control device and a drive control method that can reliably stop a rotor of a motor, particularly a stepping motor, at a stable position.

  As one of the light distribution control devices that control the light distribution of the headlamp of an automobile, a shade that blocks a part of the light emitted from the light source is configured with a variable shade, and the light shielding region is changed by switching the variable shade. Some are configured to switch. As this variable shade, for example, there is a rotary type variable shade, and a plurality of shades having different light shielding shapes are arranged radially on the peripheral surface of the rotating body that is rotationally driven, and the rotational position of the rotating body is switched by the motor. One of the shades is positioned on the outgoing light path of the light source, thereby switching the light shielding region and controlling light distribution switching.

  In such a rotary variable shade, it is necessary to control the rotational position of the rotating body with high accuracy so that any one of the shades is positioned at a predetermined position on the outgoing light path of the light source. Conventionally, a stepping motor has been used as a drive source for driving the rotating body. Since the stepping motor can perform microstep drive control that performs minute rotation angle control, it is effective for finely adjusting the rotational position of the variable shade to control light distribution with high accuracy.

  However, since the microstep drive is not always driven to rotate at a stable position, for example, when an abnormality occurs in the power supply system, the motor rotation position called out-of-step tends to become unstable. Therefore, the rotational position of the variable shade is not stable, and the light distribution becomes unstable, which is an obstacle to safe driving of the automobile.

  As a technique for stopping the stepping motor at a stable position, the technique of Patent Document 1 has been proposed. In particular, Patent Document 1 proposes a technique for quickly stopping a motor at a stable position when the stepping motor is micro-step driven.

JP2015-47010A

  The technique of Patent Literature 1 is a technique based on the premise that even when the power supply system is normal and stopped, power can be supplied from the power supply in the same manner as during normal operation. Therefore, it is doubtful whether the motor can be stably stopped when an abnormality occurs in the power supply system and it becomes difficult to receive power supply. It is conceivable that a standby power supply is provided in advance in consideration of the abnormality of the power supply system. However, there arises a problem that the cost for the standby power supply is increased and the apparatus is enlarged.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor drive control device and a drive control method capable of reliably stopping a motor at a stable position even in a situation where an abnormality occurs in a power supply system and it is difficult to receive normal power supply. It is to provide.

  The drive control device according to the first aspect of the present invention is a drive control device that drives and controls a motor capable of microstep driving, and includes a capacitor that stores power of a power source connected to the drive control device. Drive control means for moving the motor to a stable position with the power stored in the capacitor when the power supply becomes abnormal is provided.

  The drive control apparatus according to the second aspect of the present invention is a drive control apparatus for driving and controlling a motor capable of microstep drive, and stops the microstep drive of the motor when the rotation of the motor is stopped to bring the motor into a stable position. Drive control means for moving is provided. In this case, monitoring means for monitoring the power supply connected to the drive control device is provided, and rotation is stopped when the monitoring means detects an abnormality in the power supply.

  For example, the motor is a stepping motor, and the drive control means simultaneously allows the same level of current to flow through two exciting coils of the rotor or stator adjacent to each other in the rotation direction when the rotation is stopped.

  In the drive control method of the present invention, when the rotation of a motor capable of microstep drive is stopped, the microstep drive of the motor is stopped and the motor is moved to a stable position. In this case, the power supply connected to the drive control device is monitored, and rotation is stopped when a power supply abnormality is detected.

  According to the present invention, since the electric power stored in the capacitor is used, even when the power supply becomes abnormal, the motor can be reliably moved to the stable position and held at that position. In addition, according to the present invention, when the rotation of the motor is stopped, the microstep drive is stopped and the motor is instantaneously moved to a stable position, so that control with less power consumption is possible and the motor is reliably It can be held in a stable position.

1 is a schematic longitudinal sectional view of an automotive headlamp to which the present invention is applied. The conceptual block diagram of the stepping motor concerning this invention. The block circuit diagram of the drive control apparatus of this invention. The figure which expanded a part of stepping motor of FIG. The timing diagram of the electric current which flows into an exciting coil. The timing diagram of the electric current which expanded the A section of FIG. The timing diagram of the electric current at the time of stopping a motor in a stable position. The operation | movement flowchart improved when stopping a motor in a stable position. Timing diagram of improved current when stopping the motor in a stable position.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of an automotive headlamp to which a drive control device of the present invention is applied. In the headlamp HL, a lamp unit 2 is housed in a lamp housing 1 indicated by an imaginary line, and light emitted from the lamp unit 2 is transmitted through the light-transmitting cover 11 of the lamp housing 1 so that the front area of the automobile is It comes to irradiate.

  The lamp unit 2 includes an LED (light emitting diode) 21 as a light source, an elliptical reflector 22 that reflects light emitted from the LED 21 in a condensing state, and is disposed near the condensing point to be condensed. A variable shade 23 that blocks a part of the light, and a projection lens 24 that projects the light not blocked by the variable shade 23 toward the front of the automobile. The variable shade 23 is configured as a rotary variable shade, and the light blocking area of the light is changed by changing the rotation position thereof, and the light distribution of the headlamp HL is controlled to change.

  The variable shade 23 is rotationally controlled by a stepping motor 3 that is provided integrally with the lamp unit 2. The rotation of the stepping motor 3 is controlled by a drive control device 4, and the drive control device 4 is integrally supported by a part of the lamp unit 2.

  The variable shade 23 has a rotating body 231 having a columnar shape in which column axes are horizontally arranged. The column shafts 232 provided at both ends of the rotating body 231 are configured as rotating shafts, and the rotating shafts 232 are connected to the rotation output shaft 30 of the stepping motor 3 via a rotation transmission mechanism 233 including a gear mechanism or the like. It is connected. As a result, the rotational position of the rotating body 231, that is, the variable shade 23, is controlled by the stepping motor 3 so as to change the rotational position around the rotation shaft 232.

  In the variable shade 23, a plurality of shades 234 having different shapes are radially arranged on the peripheral surface of the rotating body 231, and any one of the shades 234 is changed when the rotational position of the rotating body 231 is changed. The light is selectively moved on the optical path of the lamp unit 2 to block light. Therefore, the light distribution of the headlamp HL is changed by changing and controlling the rotation position of the rotating body 231.

  FIG. 2 is a conceptual configuration diagram of the stepping motor 3. The stepping motor 3 includes a rotor 31 made of a columnar magnet (permanent magnet) provided integrally with the rotary output shaft 30 and a cylindrical stator 32 disposed on the outer periphery of the rotor 31. ing. The rotor 31 includes an even number of magnetic poles in which N poles and S poles are alternately magnetized along the circumferential direction, in this example, four magnetic poles N1, N2, S1, and S2.

  The stator 32 has a number of magnetic poles of the rotor 31 that is twice the number of magnetic poles of the rotor 31, that is, eight exciting coils (exciting cores) C1 to C8. When an electric current is passed through each of these exciting coils C1 to C8, the inner diameter end is excited to the S pole or the N pole according to the direction of the current flow. In an actual stepping motor, the number of magnetic poles of the rotor and the number of exciting coils of the stator are larger than the above-described 4 and 8, but a small number of examples are shown here to simplify the explanation.

  FIG. 3 is a block circuit diagram of the drive control device 4 for driving the stepping motor 3. The drive control device 4 includes a drive circuit unit 41, and the drive circuit unit 41 includes a motor driver 42 that rotationally drives the stepping motor 3. The drive circuit unit 41 is connected to a system power supply 5 connected to an in-vehicle battery, and electric power for driving the stepping motor 3 is input from the system power supply 5.

  The drive circuit unit 31 is connected to a capacitor 43 that stores electric power (charge) supplied from the system power supply 5 in parallel with the input terminal of the motor driver 42. Further, a diode 44 for preventing the backflow of charges from the capacitor 43 to the system power supply 5 is connected to the upstream side of the capacitor 43.

  The motor driver 42 is connected to a drive control unit 45, and controls the current flowing through the excitation coils C <b> 1 to C <b> 8 of the stepping motor 3 based on a control signal output from the drive control unit 45. Here, the exciting coils C1 to C8 flow independently at a required level and timing. Each of the exciting coils C1 to C8 is alternately excited to the S pole or the N pole at the timing when the current flows. The exciting coils C1 to C8 may be divided into a plurality of groups and the same current may be passed through each group.

  The drive control unit 45 is connected to a vehicle ECU (electronic control unit) 6 mounted on the automobile, and a light distribution switching signal for switching light distribution is input from the vehicle ECU 6. When the light distribution switching signal is input, the drive control unit 45 controls the rotational position of the stepping motor 3 with respect to the motor driver 42 so as to set the variable shade 23 to a rotational position corresponding to the light distribution. Output a control signal. As this control signal, as described later, it is possible to output a control signal for rotating the stepping motor 3 by microstep driving.

  On the other hand, the drive control unit 45 is connected with a voltage monitoring unit 46 that monitors the power supply voltage as one aspect of the abnormality of the system power supply 5 input to the drive circuit unit 41, here, the abnormality. The voltage monitoring unit 46 detects the output voltage of the system power supply 5 and outputs a warning signal to the drive control unit 45 when the detected voltage falls below a preset reference voltage. The output voltage of the system power supply 5 detected here needs to be a voltage that is not affected by the charge stored in the capacitor 43, and the voltage on the anode side of the diode 44 is detected. When the warning signal is output, the drive control unit 45 outputs a rotation stop control signal to the motor driver 42 to stop the stepping motor 3 at a stable position.

  According to the drive control device 4 having this configuration, when a light distribution switching signal is output from the vehicle ECU 6 to the drive control unit 45, the drive control unit 45 outputs a control signal corresponding to the light distribution switching signal to the motor driver 42. Then, the stepping motor 3 is controlled to a desired rotational position. In this rotational position control, the current flowing through each of the exciting coils C1 to C8 of the stator 31 of the stepping motor 3 is sequence-controlled, and so-called one-phase control, two-phase control, or 1-2-phase control is performed. The rotor 31 can be rotationally driven by the magnetic force generated between the magnetic poles N1, N2, S1, and S2 of the rotor 31. Since phase driving of this stepping motor is already known, the description thereof is omitted here.

  Here, in the drive control device 4, the motor driver 42 can microstep drive the stepping motor 3 based on a control signal output from the drive control unit 45. This microstep drive will be briefly described with reference to FIGS. 4 and 5. FIG. FIG. 4 is a diagram schematically showing a part of the rotor 31 and the stator 32 of the stepping motor 3. The magnetic pole N1 of the rotor 31 and the three exciting coils C1, C2, and C3 of the stator 32 are enlarged. It shows.

  FIG. 5 is a timing chart of currents flowing through these three exciting coils C1, C2, and C3. The vertical axis represents current level and the horizontal axis represents time. It can be said that the horizontal axis corresponds to the rotational position of the rotor 31 corresponding to the three exciting coils C1, C2, and C3.

  In FIG. 4, it is assumed that the stepping motor 3 is driven to rotate in the clockwise direction, and the center position in the rotation direction of the N1 pole of the rotor 31 (the black ▲ position in the figure) is rotated to a position P1 facing the excitation coil C1. Has been moved. That is, the N1 pole is magnetically attracted by the excitation force of the S pole of the excitation coil C1. As shown in FIG. 5, the motor driver 42 passes a current whose current level changes in a sine wave shape on the time axis through the control signals of the drive control unit 45, as shown in FIG. 5.

  Due to such current flow, the exciting force of the S pole of the exciting coil C1 gradually decreases from the state of FIG. 4, and the exciting force of the S pole of the exciting coil C2 gradually increases. Thereby, the N1 pole of the rotor 31 is rotated clockwise from the exciting coil C1 toward the exciting coil C2. When the N1 pole is rotated to the position P11 facing the exciting coil C2, the current level of the exciting coil C2 is reduced this time, and the exciting force of the S pole gradually decreases, so that the exciting coil C3 adjacent in the rotation direction As the current level is increased, the excitation force of the south pole gradually increases. Accordingly, the N1 pole is further rotated clockwise from the exciting coil C2 toward the position P18 near the exciting coil C3.

  The microstep drive of the stepping motor 3 is performed by dividing the maximum and minimum levels of current flowing through the excitation coils C1 to C8 shown in FIG. Control by step level. Thus, when the rotor 31 is rotated between the exciting coils adjacent in the circumferential direction, the rotor 31 is rotated step by step for each rotation angle corresponding to the step level.

  For example, FIG. 6 is an enlarged view of a portion A in FIG. 5, and current levels L0 to L8 flowing through the exciting coils C1 to C3 are shown on the vertical axis. When the current level of the exciting coil C1 is the maximum level L8 and the current level of the exciting coil C2 is the minimum level L0, the exciting coil C1 has the maximum exciting force of the S pole, and the N1 pole becomes P1 as shown in FIG. Rotated position. Next, when the current of the exciting coil C1 is reduced to the level L7 and the current of the exciting coil C2 is increased to the level L1, the exciting force of the S pole of the exciting coil C1 is reduced and the exciting force of the S pole of C2 is increased. As a result, the rotor 31 is rotationally moved to a position P2 where the N1 pole and the exciting force of the exciting coils C1 and C2 are balanced.

  Thus, by step-controlling the currents of the exciting coils C1 and C2, the N1 pole is rotated stepwise from the exciting coils C1 to C2, that is, from the positions P1 to P8, and the rotor 31 is micro-step driven. Become. When the N1 pole is rotated to the exciting coil C2, this time, the same control is performed on the exciting coils C2 and C3, so that the N1 pole is micro-step driven from the exciting coils C2 to C3, that is, from the positions P11 to P18. It will be.

  By this microstep drive, the stepping motor 3 is rotationally driven with a number of steps larger than the number of exciting coils C1 to C8, and fine rotation control can be realized. Therefore, in the above-described headlamp HL, the variable shade 23 can be controlled to be rotated in units of minute rotation angles, the position of the shade 23 can be controlled with high accuracy, and suitable light distribution control can be realized.

  Here, when the system power supply 5 becomes in an abnormal state and the output voltage of the system power supply 5 falls below the reference voltage, that is, the lowest voltage at which normal operation of the drive control device 4 is guaranteed, the stepping motor by the drive circuit device 4 3 normal rotation control becomes difficult. In particular, the rotational operation of the rotor 31 in the stepping motor 3 becomes unstable, the rotational position control of the variable shade 23 becomes unstable, the light distribution of the headlamp HL is not stable, and it becomes an obstacle to safe driving.

  At this time, a warning signal is output from the voltage monitoring unit 46, and the drive control unit 45 performs control to drive the motor driver 42 based on this warning signal and stop the stepping motor 3 at a stable position. The stable position in the stepping motor 3 is an intermediate position between two exciting coils adjacent in the rotation direction of the motor. For example, in the example of FIGS. 4 to 6, the position is an intermediate position P5 between the exciting coils C1 and C2, or an intermediate position P15 between the exciting coils C2 and C3. In the stable positions P5 and 15, the N1 pole is brought into a stable state by the balance of the respective exciting forces of the two exciting coils C1 and C2 or C2 and C3 sandwiched in the rotation direction. This stable state is maintained even if the magnetic forces of both excitation coils C1 and C2 or C2 and C3 disappear.

  Therefore, as shown in FIG. 7, for example, when a warning signal is output from the voltage monitoring unit 46 at a position P13 where the rotor 31 rotates and the N1 pole has passed the excitation coil C2, the N1 pole becomes the excitation coil C2. The drive control unit 45 controls the motor driver 42 to continue the micro-step drive until it moves to the stable position P15 in the middle of the excitation coil C3. In this control, the drive control device 4 and the stepping motor 3 can be driven by the electric power stored in the capacitor 43. Therefore, the stop at the stable position can be realized without the supply of power from the system power supply 5.

  However, in this control, microstep driving with a number of steps is required until the stable position is reached. When the number of required steps is large, it takes time to rotate the rotor 31 to the stable position, and the power consumption increases accordingly. In FIG. 7, time t1 is required. Further, it is not negligible that the electric charge stored in the capacitor 43 is discharged over time. Therefore, power may be consumed during the rotational movement of the rotor 31 to the stable position, and the stop at the stable position may not be completed with certainty.

  In particular, even when the N1 pole is rotated to the stable position, the exciting coils C2 and C3 are used to prevent the damping caused by the rotational inertia force of the rotor 31 (the rotation position is not stabilized and fine vibration is caused). It is necessary to hold the excited state, and in FIG. 7, it is necessary to hold the excited state only for the holding time t2. For this reason, electric power for maintaining this excited state is also required, and it may be difficult to reliably complete the stop at the stable position from this point.

  In order to eliminate the difficulty of certainty accompanying the increase in power consumption, it is preferable to use a high-capacity capacitor with a large amount of stored electricity as the capacitor 43. However, since the high-capacity capacitor is expensive and large, it is difficult to integrate the lamp unit 2 into the lamp unit 2, and even when integrated, it is difficult to incorporate the lamp housing 1. It becomes an obstacle.

  In a preferred form of the invention, as shown in the flowchart of FIG. The drive control unit determines a warning signal from the voltage monitoring unit (S1), and when the warning signal is not output, the motor driver performs microstep driving (S2). When the warning signal is output, the drive control unit 45 outputs an emergency stop signal (S3), and in response to this, the motor driver 42 stops microstep driving (S4), and instead stops the rotor 31 at a stable position. The stable stop control is executed (S5). This stable stop control S5 is a control in which the same level of current flows through each of the exciting coils C1 to C8 of the stepping motor 3, as will be described later.

  As shown in FIG. 9, if the warning signal is output from the voltage monitoring unit 46 at the position P13 where the rotor 31 rotates and the N1 pole has passed the excitation coil C2 as in the case of FIG. 7, the excitation coils C2 and C3 On the other hand, a predetermined level of current flows instantaneously. In this example, a current of level L4 that is two levels smaller than the previous level L6 is instantaneously passed through the exciting coil C2, and a current of level L4 that is two levels larger than the previous level L2 is instantaneously passed through the exciting coil C3. Shed.

  As a result, a current of the same level L4 flows through the exciting coils C2 and C3, so that a so-called two-phase drive state is established, and the exciting forces of the exciting coils C2 and C3 sandwiching the N1 pole in the rotation direction become equal. Is instantaneously moved to a stable position between these exciting coils C2 and C3. Thereafter, in order to prevent chattering due to the inertial force of the rotor 31, the excitation states of the respective excitation coils C2 and C3 are held for the holding time t2 as in the case of FIG. Therefore, the variable shade 23 is stabilized at a predetermined position, and the light distribution of the headlamp HL is also stabilized.

  As described above, in this embodiment, when a warning signal is output from the voltage monitoring unit 46, that is, when the system power supply 4 is cut off, the microstep driving so far is stopped and the two-phase driving is instantaneously performed. The rotor 31 is stopped at the stable position. Therefore, compared with the control in which the microstep driving shown in FIG. 7 is continued and the rotor 31 is rotated to the stable position, the operation time of the drive control device 4 and the stepping motor 3 at the time of emergency stop is extremely short, and the consumption Electric power can be reduced.

  Further, since the operation time at the time of emergency stop is short and almost instantaneous, even if the holding time t2 for preventing chattering after the stop is added, the time until the stable position is held can be shortened. Thereby, the influence of the discharge of the electric charge stored in the capacitor 43 is reduced, and even when a low-capacitance capacitor with a small amount of stored electricity is used, the stop at the stable position can be completed with certainty. At the same time, the drive control device 4 or the lamp unit 2 or the headlamp HL can be downsized.

  Here, when the system power supply 4 becomes in an abnormal state before the N1 pole passes through the stable position P15 and is rotated to the exciting coil C3, the following two methods are conceivable. In the first method, the motor is stopped instantaneously, and the N1 pole is reversely rotated back to the stable position P15 that has passed through, and held at the stable position P15. In the second method, the N1 pole is moved to the exciting coil C3, further moved to a stable position between the exciting coils C3 and C4, and held there. Either method can be adopted, but in this embodiment, when the motor is rotated in the reverse direction, the change in the light distribution pattern is reversed, and the driver feels uncomfortable, so the second method is adopted. Note that the first method is not preferable because it takes time to reversely rotate the motor by the rotational inertial force and return it to the stable position P15, and the power consumption increases during that time.

  In the above description, an example of operation with the N1 pole of the rotor and the excitation coils C1 to C3 of the stator has been described. However, other N poles or S poles constituting the rotor and other excitation coils of the stator are also described. It goes without saying that the same control as in the embodiment is performed. The same applies to stepping motors in which the number of N and S poles of the rotor and the number of exciting coils are different.

  The present invention does not urgently stop the stepping motor when an abnormality occurs in the system power supply as described in the embodiment, but when the stepping motor is required to be instantaneously stopped at a stable position for other reasons. It can also be applied to control.

  The motor to which the present invention is applicable may be a stepping motor having a configuration in which a stator is provided on the inner diameter side and a rotor is disposed on the outer diameter side. Further, a stepping motor in which the stator is composed of a magnet and the exciting coil is disposed on the rotor may be used. Furthermore, the present invention can be applied to any motor capable of microstep driving.

  In the embodiment, the example in which the motor according to the present invention is configured as a drive source for rotationally driving the variable shade has been described. However, swivel control for tilting the lamp optical axis in the horizontal direction and tilting the lamp optical axis in the vertical direction are described. You may apply as a motor for the drive of leveling control. That is, in a mechanism that varies the light distribution by rotating the optical unit so that the light source is at the rotation center in a state where the optical unit is arranged so that the light source is at the optical center, the optical unit is It can be applied as a device for controlling rotation. In particular, optical units in recent years have been made lighter by using LEDs and plastic lenses, so that stepping motors can be applied.

1 Lamp housing 2 Lamp unit 3 Stepping motor (Motor capable of micro-step drive)
4 Drive control device 5 System power supply 6 Vehicle ECU
21 Light source (LED)
22 reflector 23 variable shade 24 projection lens 30 rotating shaft 31 rotor 32 stator 41 drive circuit section 42 motor driver 43 capacitor 44 diode 45 drive control section (drive control means)
46 Voltage monitor (monitoring means)
N1, N2, S1, S2 Magnetic pole (rotor)
C1-C8 exciting coil (stator)
P5, P15 Stable position

Claims (6)

  A drive control device for driving and controlling a motor capable of microstep driving, comprising a capacitor for storing power of a power source connected to the drive control device, and storing the capacitor in the capacitor when the power source becomes abnormal A drive control device for a motor, comprising drive control means for moving the motor to a stable position with the generated electric power.   A drive control device for driving and controlling a motor capable of microstep driving, comprising drive control means for stopping microstep driving of the motor and moving the motor to a stable position when rotation of the motor is stopped. A motor drive control device.   3. The monitoring device according to claim 2, further comprising a monitoring unit that monitors a power source connected to the drive control device, wherein the drive control unit stops rotation of the motor when the monitoring unit detects an abnormality in the power source. Motor drive control device.   The motor is a stepping motor in which one of a stator and a rotor is composed of a plurality of exciting coils, and the other is composed of a magnet having a plurality of magnetic poles. 4. The motor drive control device according to claim 2, wherein currents of the same level are simultaneously passed through the exciting coils.   A drive control method for driving and controlling a motor capable of microstep drive, wherein when the rotation of the motor is stopped, the microstep drive is stopped and the motor is moved to a stable position. The motor drive control method according to claim 5, wherein a power supply connected to a drive control device that drives and controls the motor is monitored, and rotation of the motor is stopped when an abnormality of the power supply is detected.

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