Positioning device and control method thereof

Abstract

To provide a positioning device capable of positioning control with high accuracy.SOLUTION: A positioning device includes an actuator consisting of a DC motor, a reduction mechanism, and a single-phase rotation sensor that detects the amount of rotational displacement of the reduction mechanism, and an electronic control device for electrically driving the DC motor. The electronic control device learns T2, the time it takes for the motor to go from power supply device off to stop, defines a target rotation stop position MP as a location roughly midway between a rising edge N+4f and a falling edge N+4r of an output pulse of the rotation sensor, and performs a deceleration control to stop the DC motor.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an electric drive system that drives a moving body by an actuator incorporating an electric motor and controls it to a predetermined position, and in particular to a positioning device and a control method thereof that are applied to a movable part such as an electric power seat of a vehicle and perform positioning control with high precision. [Background technology]

[0002] Conventionally, this type of positioning device has been mechanically linked to the moving body to be driven, and generally comprises an actuator made up of a DC motor, a reduction mechanism, and a rotation sensor that detects the amount of rotational displacement of the reduction mechanism, as well as an electronic control device that electrically drives the DC motor.

[0003] Specifically, a known electric power seat for a vehicle is configured with an actuator 2 attached to the seat back as shown in Fig. 1 and an electronic control device 1 that receives signals from an operating switch 3 and drives the actuator. Fig. 2 shows a detailed example of the actuator portion. In the actuator portion of FIG. 2, a second gear 212 fixed to the seat frame meshes with a small-diameter gear (not shown) arranged coaxially with the first gear 211, and the first gear meshes with a worm gear 210 connected to the motor shaft.

[0004] With the configuration shown in FIG. 2, when the motor 200 is driven, the worm gear 210 rotates to turn the first gear 211, and the small diameter portion (not shown) of the first gear rotates on its axis so as to revolve around the periphery of the second gear 212, thereby making it possible to electrically adjust the tilt angle of the seat back.

[0005] Fig. 3 is a diagram showing a detailed example of the rotation sensor part. The rotation sensor part is formed by magnet 201 consisting of a single magnetic pole pair arranged coaxially with the motor rotating shaft, and Hall element 202 arranged in the fixed part and detecting the magnetic field generated by the magnet as an electric signal, and these two components constitute a known single-phase rotary encoder.

[0006] As a result, the Hall element 202 outputs one pulse of an electric signal every time the motor shaft rotates once. The electronic control device 1 is configured to integrate this number of pulses in a predetermined direction, calculate it as the tilt angle of the seat back, and store it.

[0007] The above configuration is applied not only to the inclination of the seat back, but also to the control of the front-rear sliding position of the seat and the front-rear height control of the seat cushion. Since these various positioning controls can be performed electrically, a well-known memory power seat function is realized that reproduces any seat position set for multiple drivers separately with a one-touch operation.

[0008] However, single-phase rotary encoders cannot determine the rotation direction of the motor shaft from the output signal of the Hall element. Therefore, as described in Patent Document 1, when the motor is stopped when the drive mechanism reaches the end of its movable range, the motor is driven in the reverse direction by the reaction force from the load side, causing a discrepancy between the actual position of the sheet and the position detected and stored by the device.

[0009] According to Patent Document 1, when the motor stops at the end of its movable range, it is determined that a mechanical lock has occurred, and the rotation pulses generated during the motor-off period are counted as reverse rotation. Alternatively, a solution has been proposed for accurately storing the seat position by, for example, holding a user's request to inhibit motor drive for a short period of time until motor rotation can be determined. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2011-42280 A Summary of the Invention [Problem to be solved by the invention]

[0011] However, the cause of the rotation sensor's erroneous detection of the movable positions of the various parts of the seat is not limited to the reversal movement at the end of the movable range. In addition, the cause of the rotation sensor's erroneous detection of the operating positions of the various parts of the seat may be the motor stopping before the rotation sensor generates a pulse due to a short time of user operation within the movable range.

[0012] For example, assuming that the stopping position within the movable range is very close to the edge of the pulse output by the rotation sensor, after power to the electronic control device is cut off, the motor may rotate slightly due to external forces acting on various parts of the seat. At this time, the physical rotation angle of the motor shaft due to the slight rotation of the motor may exceed the edge position of the output pulse of the rotation sensor, and when power is applied to the electronic control device again to change the seat position, one pulse count will be missing.

[0013] Furthermore, if the stop position is very close to the edge of the pulse output by the rotation sensor, the motor may rotate by a small angle immediately after it has stopped due to backlash in the reduction mechanism, etc. In this case, if the motor stops on the falling edge of the rotation sensor pulse, the rising edge in the opposite direction will be detected immediately afterwards. Therefore, the electronic control device will recognize that the moving part has moved one pulse in the controlled direction, and will erroneously recognize that it has moved one pulse more than the actual stopping position.

[0014] As a result, there was an issue where repeating the memory power seat regeneration operation about 100 times would result in a significant deviation from the originally set seat position.

[0015] The present invention has been made in consideration of the above-mentioned problems, and provides a positioning device comprising an actuator made up of a DC motor, a reduction mechanism, and a single-phase rotation sensor that detects the rotational displacement amount of the reduction mechanism, and an electronic control device that electrically drives the DC motor, which enables high-precision positioning control without causing an error between the mechanical displacement amount of the controlled object and the integrated number of pulses of the rotation sensor stored in the electronic control device. [Means for solving the problem]

[0016] The positioning device according to the invention of claim 1 is a positioning device comprising an actuator connected to a moving body and composed of a DC motor, a reduction mechanism, and a single-phase rotation sensor that detects the amount of rotational displacement of the reduction mechanism, and an electronic control device that electrically drives the DC motor, wherein the electronic control device is characterized in that it comprises a stop control means that performs deceleration control to stop the DC motor by setting a target rotation stop position to approximately the midpoint between the rising edge and the falling edge of the output pulse of the rotation sensor, and a learning control means that learns the target rotation stop position.

[0017] In the positioning device according to the invention of claim 2, the stop control means performs deceleration control so as to decelerate and stop the DC motor in an inertial rotation mode in which power supply to the DC motor is cut off.

[0018] The positioning device according to the invention of claim 3 is characterized in that the stop control means performs deceleration control so as to decelerate and stop the DC motor by a brake mode in which the power supply terminals of the DC motor are electrically short-circuited.

[0019] The positioning device according to the invention of claim 4 is characterized in that the stop control means performs deceleration control to decelerate and stop the DC motor by a forced brake mode in which power is applied to the power supply terminals of the DC motor to provide a rotational force in a direction opposite to the direction in which the DC motor rotates during operation.

[0020] The positioning device according to the invention of claim 5 is characterized in that the learning control means detects a first timing at which one output of the rotation sensor is generated, detects a second timing longer than the first timing at which the other output of the rotation sensor is generated, and if one output of the rotation sensor is detected at a third timing between the first timing and the second timing, sets the third timing to a new first timing, and if the other output of the rotation sensor is detected, sets the third timing to a new second timing, and learns the target rotation stop position by detecting the output of the rotation sensor at a new third timing between the new first timing or the original first timing and the new second timing or the original second timing.

[0021] The positioning device according to the invention of claim 6 is characterized in that it repeatedly detects the output of the rotation sensor at a new third timing between the new first timing or the original first timing and the new second timing or the original second timing, and detects and learns an approximately midpoint between the rising edge and the falling edge of the output pulse.

[0022] The positioning device according to the invention of claim 7 is characterized in that it performs forced braking to apply a rotational force in the opposite direction using a forced braking interval determined by the new third timing.

[0023] The positioning device according to the invention of claim 8 is characterized in that the learning control means detects a first timing at which one of the outputs of the rotation sensor is generated, detects a second timing longer than the first timing at which the other output of the rotation sensor is generated, and when one of the outputs of the rotation sensor is detected at a third timing obtained by adding a predetermined amount to the first timing or subtracting a predetermined amount from the second timing, sets the third timing as a new first timing, and when the other output of the rotation sensor is detected, sets the third timing as a new second timing, and learns the target rotation stop position by detecting the output of the rotation sensor at the new third timing obtained by adding or subtracting the predetermined amount.

[0024] The positioning device according to the invention of claim 9 is characterized in that it repeatedly detects the output of the rotation sensor at a new third timing to which the specified amount is added or subtracted, and detects and learns approximately the midpoint between the rising edge and the falling edge of the output pulse.

[0025] The positioning device according to the invention of claim 10 is characterized in that it performs forced braking to apply a rotational force in the opposite direction using a forced braking interval determined by the new third timing.

[0026] The positioning device according to an eleventh aspect of the present invention is characterized in that the moving body is an electric power seat for a vehicle.

[0027] The positioning device according to the invention of claim 12 is characterized in that the moving body is an electric tilt / telescopic steering device for a vehicle. Effect of the Invention

[0028] According to the invention of claim 1, the electronic control device includes a stop control means that operates to control the deceleration of the DC motor to stop the motor, with the target rotation stop position being approximately the midpoint between the rising edge and the falling edge of the output pulse of the rotation sensor, and a learning control means that learns the target rotation stop position. Since the rotation stop position of the motor within the movable range of the moving body is not near the edge of the pulse output by the rotation sensor, there is an effect that the rotation sensor does not generate an erroneous pulse even when the motor rotates slightly due to an external force acting on each part of the seat.

[0029] Therefore, even if the regenerating operation of the memory power seat is repeated several hundred times, there will be no deviation from the originally set seat position.

[0030] According to the invention of claim 2, the stop control means can stop the motor at the target rotation stop position in a coasting rotation mode in which the power supply to the DC motor is cut off.

[0031] According to the invention of claim 3, the stop control means can stop the DC motor at the target rotation stop position by a known brake mode in which the power supply terminals of the DC motor are electrically short-circuited, so that the motor can be stopped accurately at the target rotation position in a short period of time.

[0032] According to the invention of claim 4, the stop control means can stop the DC motor at the target rotation stop position by a forced brake mode in which electric power is applied to the power supply terminals of the DC motor to provide a rotational force in the opposite direction to the direction in which the DC motor rotates during operation, so that the motor can be stopped at the target rotation stop position more accurately in a shorter time.

[0033] According to the invention of claim 5, the learning control means detects a first timing at which one output of the rotation sensor is generated, detects a second timing longer than the first timing at which the other output of the rotation sensor is generated, and when one output of the rotation sensor is detected at a third timing between the first timing and the second timing, sets the third timing as a new first timing, and when the other output of the rotation sensor is detected, sets the third timing as a new second timing. By detecting the output of the rotation sensor at the new first timing or the new third timing between the original first timing and the new second timing or the original second timing, it is possible to learn a target rotation stop position that is approximately the midpoint between the rising edge and the falling edge of the output pulse.

[0034] According to the invention of claim 6, the learning control means repeatedly detects the output of the rotation sensor at a new first timing or a new third timing between the original first timing and a new second timing or the original second timing, and detects an approximately midpoint between the rising edge and the falling edge of the output pulse, thereby making it possible to learn the target rotation stop position, which is approximately the midpoint.

[0035] According to the invention of claim 7, the learning control means can perform forced braking by applying a rotational force in the reverse direction at a forced braking interval determined by the new third timing, and can learn the forced braking interval for stopping the rotor at the target rotation stop position, which is an intermediate position.

[0036] According to the invention of claim 8, the learning control means detects a first timing at which one of the rotation sensor outputs is generated, detects a second timing longer than the first timing at which the other of the rotation sensor outputs is generated, and when one of the rotation sensor outputs is detected at a third timing obtained by adding a predetermined amount to the first timing or subtracting a predetermined amount from the second timing, the learning control means sets the third timing to a new first timing, and when the other of the rotation sensor outputs is detected, sets the third timing to a new second timing, and by detecting the output of the rotation sensor at the new third timing obtained by adding or subtracting a predetermined amount, the learning control means can learn a target rotation stop position which is approximately midway between the rising edge and falling edge of the output pulse.

[0037] According to the invention of claim 9, the learning control means repeatedly detects the output of the rotation sensor at a new third timing obtained by adding or subtracting a predetermined amount, and detects the approximately midpoint between the rising edge and the falling edge of the output pulse, thereby making it possible to learn the target rotation stop position, which is approximately the midpoint.

[0038] According to the invention of claim 10, the learning control means can perform forced braking by applying a rotational force in the reverse direction at a forced braking interval determined by the new third timing, and can learn the forced braking interval for stopping the motor at the target rotation stop position, which is an intermediate position. [Brief description of the drawings]

[0039] [Figure 1] FIG. 2 is a diagram showing the structure of an electric power seat. [Diagram 2] FIG. 2 is an enlarged view of the vicinity of the reclining actuator. [Diagram 3] FIG. 2 is a diagram showing the structure of a DC motor and a rotation sensor. [Figure 4] 4A to 4C are diagrams illustrating the operation of a rotation sensor. [Diagram 5] FIG. 2 is a diagram showing the configuration of a control device. [Figure 6]FIG. 6A is a diagram showing the motor stopping and the stopping position, and FIG. 6B is a diagram showing the motor stopping and the stopping position when reverse bias is applied. [Figure 7] 11 is a diagram showing motor stop and stop position during motor output adjustment. FIG. [Figure 8] This is a diagram showing the overall CPU control flow. [Figure 9] FIG. 13 is a diagram showing the flow of the CPU learning mode. [Figure 10] FIG. 11 is an explanatory diagram of a stop timing in a learning mode. [Figure 11] FIG. 13 is a diagram showing a flow of a learning mode in another modified example of the CPU. [Figure 12] FIG. 13 is a diagram showing a control flow in a normal mode. [Figure 13] FIG. 11 is a diagram showing a motor drive stop control flow. [Figure 14] 5A and 5B are diagrams showing pulse signals according to a motor rotation state. [Figure 15] FIG. 13 is a diagram showing the stop position when the motor stops at a pulse edge. [Figure 16] FIG. 13 is a diagram showing the stop position when an arbitrary timing is set as the motor stopping start point. [Figure 17] FIG. 17(A) shows the case where the output of the electronic control device is turned off at the timing of the pulse edge to stop the motor, and FIG. 17(B) shows the case where a motor reverse rotation output is applied to the motor. [Figure 18] FIG. 13 is a diagram showing a case where a motor reverse rotation output is applied to the motor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] [Embodiment] Hereinafter, a positioning device and a control method thereof according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows the overall structure of an electric power seat. An actuator 2 for reclining is fixed to a frame that forms the internal framework of the electric power seat. An electronic control device 1 electrically controls the actuator 2 and receives a signal from an operation switch 3.

[0041] 2, the actuator 2 is equipped with a DC motor 200, a worm gear 210, a first gear 211, and a second gear 212. The internal structure of the motor as viewed from the A direction is shown in FIG.

[0042] The magnet 201 in FIG. 3 is a ring-shaped ferrite magnet having a pair of N and S magnetic poles that is fixedly connected to the rotor of the DC motor 200 on the same axis, and rotates in conjunction with the rotor of the motor 200.

[0043] Hall element 202 is fixed to a fixed part that is integrated with the housing of the motor, close to the magnet and separated by a distance of about 2 mm. With this structure, when magnet 201 rotates in conjunction with the rotor of motor 200, the magnetic flux density of Hall element 202 changes in a sinusoidal wave shape with the rotor angle of motor 200 being 360 degrees as one cycle, as shown in Figure 4.

[0044] The Hall element 202 is configured such that the output signal is processed by a known comparator circuit (not shown) and converted into a square wave synchronized with the sine wave with a threshold value of magnetic flux density ±1 mT. In order to avoid chattering of the output signal near the threshold value, electrical hysteresis is provided, and the magnetic flux density conversion value equivalent to this hysteresis is ±1 mT.

[0045] The maximum magnetic field level and the minimum magnetic field level in FIG. 4 are abbreviated expressions of the magnetic flux density at the Hall element 202 which varies due to errors in the magnetization level of the magnet 201, temperature changes, or variations in magnetomotive force due to durability deterioration, as well as variations in the assembly gap between the magnet 201 and the Hall element 202, variations in the sensitivity of the Hall element 202, etc.

[0046] The threshold value of ±1 mT is set because it is necessary to set a threshold value that is sufficiently small compared with the magnetic flux density at the minimum magnetic field level.

[0047] From the above, the output signal of the Hall element 202 is compared with a threshold voltage obtained by converting the magnetic flux density into an electrical level by a comparator (not shown), and is converted into a square wave and output as a rotation signal of the motor 200.

[0048] As is clear from a comparison between the threshold value and the sinusoidal magnetic flux density, the square wave signal output from the comparator is inverted near the edge of the square wave output from the comparator at a small rotation angle of the magnet 201 .

[0049] Hereinafter, the magnet 201, the Hall element 202, and the comparator (not shown) that outputs a rectangular wave signal will be referred to as a rotation sensor 20 as a whole.

[0050] Here, assuming that the rotation stop position of the motor 200 when the electronic control device 1 drives the reclining mechanism of the electric power seat is extremely close to the edge of the pulse output by the rotation sensor 20, after the power supply to the motor 200 is cut off, the motor 200 may rotate slightly due to external forces acting on various parts of the seat. At this time, the rotation angle of the physical shaft due to the minute rotation of the motor 200 may exceed the edge position of the output pulse of the rotation sensor 20, and when the motor 200 is energized again to change the seat position, one count of pulses will be missing.

[0051] Furthermore, if the rotation stop position of the motor 200 is very close to the edge of the pulse output by the rotation sensor 20, immediately after the rotation of the motor 200 stops, the motor 200 may rotate by a small angle due to backlash of the worm gear 210, the first gear 211, and the second gear 212, etc. In this case, if motor 200 stops at the falling edge of the pulse of rotation sensor 20, a rising edge in the opposite direction may be detected immediately afterwards. In this case, electronic control device 1 will mistakenly recognize that the reclining mechanism has moved one pulse in the controlled direction, and will erroneously recognize that it has moved one pulse more than the actual stop position.

[0052] The electric power seat of the embodiment can store optimal driving positions set by multiple users, and at the same time, each user can correctly reproduce the position that he or she has set.

[0053] The electronic control device 1 is configured to count, accumulate, and store the seat positions, such as the reclining position, fore-aft position, and seat height position, of the seat operated by the user during initial setup by the actuator 2 by counting the pulses output from the rotation sensor 20 while the actuator 2 is operating.

[0054] Next, when another user changes each of the positions, the electronic control device 1 re-counts, accumulates, and stores the amount of change in the number of output pulses of the rotation sensor 20, and when the user who performed the initial setting operates the switch 3, it counts the number of output pulses of the rotation sensor 20 at the same time as energizing the DC motor 200 of the actuator 2, and matches the accumulated pulse value with the initial setting value, thereby restoring the initially set seat position.

[0055] However, as mentioned above, if the motor rotation stop position is extremely close to the edge of the pulse output by the rotation sensor 20, the electronic control device 1 may erroneously recognize the motor rotation angle by one count of the output pulse of the rotation sensor 20, resulting in a deviation from the user's initial setting position or the reproduced seat position.

[0056] 5 shows a block diagram of the control device 800. The control device 800 is controlled by a CPU 801. A communication data control unit 802 is connected to the CPU 801, and the control device 800 can operate in cooperation with other control units via the communication data control unit 802. Information from the control device 800 is transmitted via Tx 805. Information required for motor drive, such as motor drive timing and motor movement target points, is received via Rx 806. Also, the switch input control section 803 can detect the states of the direction specification switches 807 and 808 to drive the motor. The motor 809 is driven by the CPU 801 via a motor drive circuit 804. The motor drive circuit 804 drives the motor by opening the power supply terminals, shorting the power supply terminals, inverting the polarity of the applied voltage, and outputting a motor ON / OFF signal. An H-bridge circuit is used for the motor drive circuit 804. In addition, the pulse signal output from the motor 809, the signal from the thermistor 810 for measuring the motor temperature, the current signal flowing through the motor drive circuit 804, and the voltage signal applied to the motor are connected to the CPU 810, allowing the CPU to grasp the state of the motor.

[0057] FIG. 6(A) shows the most basic embodiment of the positioning device and its control method of the present invention, in which the electronic control device 1 integrates the output pulses of the rotation sensor 20 and illustrates the case where the vicinity of the N+4 count is set as the target rotation stop position.

[0058] 6A, until time t1, the electronic control device 1 energizes the power supply terminal (not shown) of the DC motor 200 to move the reclining mechanism in a predetermined direction. At this time, the motor rotation speed is v, and the rotation sensor 20 outputs a rectangular wave pulse with a predetermined period.

[0059] The electronic control device 1 has learned in advance the time T2 required from when the motor is powered off until it stops. At time t1, the electronic control device 1 opens the power supply terminal to the DC motor 200 and stops the power supply to the DC motor 200, thereby starting to stop the motor (inertial rotation mode).

[0060] By cutting off the power supply, the DC motor 200 gradually slows down and stops at time t2 (target rotation stop position MP) near the midpoint between the falling edge f of the N+4 count of the output pulse of the rotation sensor 20 counted by the electronic control device 1 and the rising edge r of the N+4 count.

[0061] As a result, the rotation stop position of DC motor 200, i.e., the rotation stop position of rotation sensor 20, stops approximately halfway between the falling edge f and rising edge r of the pulse output by rotation sensor 20. Therefore, even if motor 200 rotates due to an external force after stopping as described above, no erroneous pulse will be generated unless it rotates by more than ±90 degrees.

[0062] In the example of FIG. 6A, the pulse is set to the center between the falling edge and the rising edge of the pulse, but the present invention is not limited to this and may be set to the center of the pulse edge that appears between the rising edge and the falling edge of the pulse.

[0063] The time T2 from time t1 to time t2 can take different values ​​depending on the deceleration factor of the motor. The deceleration factor can be the frictional force of the mechanism or the presence or absence of a braking force due to the regenerative current of the motor, and a combination of these factors may be used. Braking due to regenerative current is a known technology and is not illustrated here.

[0064] As another form, as shown in Fig. 6(B), there is a method of braking the motor by applying a reverse rotation bias to the power supply terminal, which applies power (reverse voltage) that gives the motor a rotational force in the opposite direction to the direction of rotation (forced brake mode). Even in this case, it is possible to combine the frictional force of the mechanism or the brake using the regenerative current of the motor (brake mode) in addition to the reverse brake. When the frictional force of the mechanism or the motor load fluctuates greatly, it is preferable to increase the overall braking force by performing braking using regenerative current (brake mode) that electrically shorts the power supply terminals of the motor, or by using reverse bias. It is also possible to use a combination of two or more of the above-mentioned inertial rotation mode, forced brake mode, and brake mode.

[0065] The overall control flow of the CPU 801 in FIG. 5 will be described with reference to FIG. The CPU 801 determines whether the learning mode has been instructed (S98). The learning mode is instructed by a command by communication from a tester at the time of inspection before shipping the vehicle or at the time of inspection before vehicle inspection. Instead of the command, a start switch may be provided. When the learning mode is instructed (S98: Yes), the learning mode is started, and the CPU 801 learns the time T2 for stopping the motor at the midpoint between the falling edge f and the rising edge r of the output pulse (target rotation stop position MP) after turning off the above-mentioned motor output signal (S100). Unless the learning mode is instructed (S98: No), the normal mode is executed (200). In the normal mode, the motor is controlled to adjust the seat position, and when the motor is stopped, the motor is stopped using the time T2 determined in the learning mode.

[0066] FIG. 9 shows a control flow of the CPU 801 in the learning mode. In steps S12, S14, and S16, stop timing 1 and stop timing 2 that have different pulse outputs when the motor is stopped are found. In step S12, stop timing 1 at which the pulse output is L when the motor is stopped is found, as shown in FIG. 7(A). In step S14, stop timing 2 at which the pulse output is H when the motor is stopped is found, as shown in FIG. 7(B). It is necessary to ensure that two or more pulse edges do not occur between stop timing 1 and stop timing 2. Also, stop timing 2 is after stop timing 1. In the subsequent processes, stop timing 1 and stop timing 2 are adjusted, and stop timing 3 for stopping at a pulse edge is learned, as shown in FIG. 7(C).

[0067] In step S18, the stop timing 3 is set to a point between the stop timing 1 and the stop timing 2, that is, the midpoint in this case. Stop timing 3 = (Stop timing 1 + Stop timing 2) / 2 If you want to find stop timing 3 from either stop timing 1 or stop timing 2, you can do so by changing the denominator.

[0068] In step S20, the motor is stopped at stop timing 3. Then, in step S22, (1) if the pulse output is L at stop timing 3 as shown in Fig. 10(B), stop timing 3 is set as new stop timing 1. That is, if the pulse output is the same output L as when it was stopped at stop timing 1, special stop timing 3 (timing 3 at which it stops at a pulse edge) will exist between the current stop timing 3 and stop timing 2.

[0069] On the other hand, (2) if the pulse output is H at stop timing 3 as shown in Fig. 10(C), stop timing 3 is set as the new stop timing 2. In other words, if the pulse output is the same H output as when it was stopped at stop timing 2, special stop timing 3 will exist between the current stop timing 3 and stop timing 1.

[0070] Then, after the judgment in step S24, the process returns to step 18, where the rotation is stopped at new stop timing 3 in step S20, either at a new first timing or at a new third timing between the original first timing and the new second timing or between the original second timing, and the output of the rotation sensor is detected in step S22 to readjust stop timing 1 and stop timing 2, thereby determining special stop timing 3.

[0071] By repeating this process, the determined stop timing 3 approaches the special stop timing 3. At this time, if it is attempted to approach the stop timing 3 as close as the resolution allows, the number of times the "stop and measurement process" is executed increases, which takes time. For this reason, in step S24, when the difference between the previous stop timing 3 and the current stop timing 3 becomes sufficiently small, the stop timing 3 is determined to be the special stop timing 3 (S24: Yes), and the process ends.

[0072] Details regarding pulse edge separation measurements are shown in FIG. Motor speed can be measured by measuring the pulse edge interval. When measuring the speed using the average pulse edge interval, the speed is calculated from the average pulse edge interval that occurs during period B from the end of motor rise period A to the start of motor stop in order to accurately measure the speed during steady rotation. When measuring the speed using the pulse edge interval just before the motor stops, the speed is calculated from the pulse edge interval in period C.

[0073] The forced braking mode will be described with reference to Fig. 17. Fig. 17(A) shows a case where the forced braking interval is set to 0, and the output of the electronic control device 1 is turned off at the pulse edge timing to stop the motor.

[0074] Figure 17(B) shows a case where the motor is stopped by applying a motor reverse rotation output from the electronic control device 1 to the motor. The reverse rotation output predicts the pulse edge that would be generated if the motor was not reversed, and is applied for an interval of Tr0 before and after that timing. In the case of Figure 17(B), since the reverse rotation interval (2 x Tr0) is large, it shows that the motor is stopped without generating a pulse edge. The motor stop timing in Figure 17(B) is the timing at which the motor starts to reverse. In the state shown in Figures 17(A) and 17(B), there is no signal indicating the timing when the motor has come to a complete stop, so it is not possible to measure the interval at which the output of the electronic control device 1 needs to be reversed so that the motor will come to a complete stop simultaneously with the end of reverse rotation.

[0075] 18 shows a case where the reverse rotation interval (2 x Tr0) is gradually decreased and the motor is rotated in reverse at intervals of (2 x Tr1). This shows that if a reverse rotation output is applied to the motor at stop timing 3, which exists between output stop timing 1 and stop timing 2, the motor complete stop timing can be matched with the output edge of the pulse signal. In this way, when the timing of the motor complete stop and the output edge of the pulse signal overlap, T2 can be measured by measuring the time from the start of the reverse rotation output of the electronic control device 1 to the pulse edge. The stop timing 3 when the motor complete stop timing and the output edge of the pulse signal overlap is called special stop timing 3. The motor stop timing in Fig. 18 is the timing when the motor starts to rotate in the reverse direction. In Fig. 17(B) and Fig. 18, the reverse rotation time is changed in accordance with the change in the motor stop timing.

[0076] A modified example of the learning method is shown in FIG. Similar to steps S12 to S16 in FIG. 9, stop timing 1 and stop timing 2 that have different pulse outputs are found in steps S32 to S .

[0077] In step S38, stop timing 3 is determined between stop timing 1 and stop timing 2. Here, the timing moved from stop timing 1 toward stop timing 2 by a predetermined amount 1 is set as stop timing 3. Stop timing 3 = Stop timing 1 + Predetermined amount 1 Alternatively, the timing shifted from the stop timing 2 toward the stop timing 1 by a predetermined amount 1 can be set as the stop timing 3. Stop timing 3 = Stop timing 2 - Predetermined amount 1

[0078] In step S40, the motor is stopped at stop timing 3. Then, in step S42, (1) if the pulse output is L at stop timing 3, stop timing 3 is set as new stop timing 1. That is, if the pulse output is the same output L as when it was stopped at stop timing 1, special stop timing 3 will exist between the current stop timing 3 and stop timing 2.

[0079] On the other hand, (2) if the pulse output is H at stop timing 3, stop timing 3 becomes the new stop timing 2. In other words, if the pulse output is the same H output that was stopped at stop timing 2, special stop timing 3 will exist between the current stop timing 3 and stop timing 1.

[0080] Then, after the judgment in step S44, the process returns to step 38, where the rotation is stopped at new stop timing 3 in step S40, either at a new first timing or at a new third timing between the original first timing and the new second timing or between the original second timing, and the output of the rotation sensor is detected in step S42 to readjust stop timing 1 and stop timing 2, thereby determining special stop timing 3.

[0081] Then, when the stop timing 3 is determined (S44: Yes), the process ends.

[0082] FIG. 12 shows the control flow of the CPU 801 in the normal mode. When the CPU is powered on, the flow shown in Fig. 12 starts. First, in step S901, an initialization process is executed. In this initialization process, the CPU ports and internal timers are initialized, and initial values ​​are set in the memory. This initialization process is executed only once after the CPU is powered on. Next, in step S902, the communication data control unit is controlled. In this control, the communication data control unit 802 extracts the data being received and writes the data to be transmitted to the communication data control unit 802.

[0083] Next, in step S903, the SW input control unit 803 is controlled. In this control, chattering absorption processing is performed to determine the SW state, and the drive request to the motor is set / reset according to the determined SW state. Next, in step S904, control is performed to read the signal inputs, which include reading the current flowing through the motor, the voltage applied to the motor, the motor pulse signal, and the motor temperature, and storing them in memory.

[0084] Next, in step S905, the movement target calculation unit controls to calculate a target movement position when the motor moves to one of multiple positions registered in advance or when it moves a specified amount from the current position. The current position and movement position are stored by a pulse counter that counts the output of the Hall sensor, and the drive request to the motor is set or reset according to the difference between the target position and the current position.

[0085] Next, in step S906, motor drive start control is performed, in which the motor drive circuit 804 is designated with a motor ON / OFF signal in response to the set / reset state of the drive request described above, thereby executing motor drive. Next, in step S907, motor drive stop control is performed, in which a motor ON / OFF signal is specified for the motor drive circuit 804 to end the motor drive. Finally, in step S908, the process waits for one routine time to elapse, and if the predetermined time has elapsed, steps S902 to S907 are executed again.

[0086] The details of the motor stopping mode will now be described. The motor drive stop control flow is shown in Fig. 13. In step S1001, the speed of the motor being driven is calculated. The speed is calculated by measuring the average pulse edge interval while the motor is being driven, or the time of the pulse edge interval just before the motor is stopped.

[0087] Details regarding this pulse edge separation measurement are shown in FIG. To accurately measure the speed during steady rotation, the average pulse edge interval is calculated by averaging the pulse edge intervals that occur during period B from the end of data rise period A to the start of motor stopping. Period C can be used as the final pulse edge interval. This means: Angular velocity calculated from "average time between pulse edges in period B (T0avr)" =π / T0avr=ωavr and "Angular velocity calculated from the time (T0sgl) of the final pulse edge interval (period C) =π / T0sgl=ωsgl Since it is possible to calculate

[0088] Next, in step S1002, the time required from when the motor output signal is turned off until the motor stops is detected. This time corresponds to T2 in FIGS. FIG. 15 (motor stop starting point 1) shows the case where the motor's current rotation angle is unknown at the timing when it is determined that the motor needs to be stopped. In this case, the timing when the pulse edge is detected is taken as the motor rotation stop starting point. FIG. 16 (motor stop starting point 2) shows the case where the motor's current rotation angle θ is known at the timing when it is determined that the motor needs to be stopped. If the motor's current rotation angle θ is known, that point in time is taken as the motor rotation stop starting point. The time T2 learned in the learning mode is corrected taking into account the motor rotation speed and environmental conditions such as temperature and motor load.

[0089] Next, in step S1003, the starting point (stop starting point) of a timer that measures the timing to turn off the motor output signal is determined. This stopping start point refers to the timing at which measurement of T1 in Figures 15 and 16 begins. Figure 15 shows that if the pulse edge is the stopping start point and the motor output signal is turned OFF after T1 has elapsed, the motor will stop after T2 has elapsed. In other words, the deceleration control is started at a specified timing synchronized with the output pulse of the rotation sensor so that the difference between the estimated stopping position and the target rotation stopping position becomes zero. T1 should be adjusted so that when the motor stops, it stops exactly in the middle between the pulse edges. In other words, Rotation angle at time T1+T2=π+(1 / 2)×π That would be good. If the interval between T1 and T2 is large and crosses (n) pulse edges between T1 and T2, Rotation angle at time T1+T2=n×π+(1 / 2)×π That would be good. In FIG. 15, one pulse edge is crossed, so n=1.

[0090] FIG. 16 shows a case where the timing at which it is determined that the motor needs to be stopped, such as when SW807 and SW808 are OFF and the target movement position is reached, is set as the stopping start point. This indicates that if the motor output signal is turned off after T1 has elapsed from the starting point of stopping, the motor will stop after T2 has elapsed. T1 can be adjusted so that the motor stops exactly in the center between the pulse edges. If the motor rotation angle at the timing when it is determined that the motor needs to be stopped is θ, then Rotation angle at time T1+T2=n×π-θ+(1 / 2)×π In FIG. 16, n=2 because two pulse edges are crossed. In this case, it is necessary to recognize θ by constantly measuring the motor rotation speed while the motor is being driven. The angular velocity θ can be calculated from the pulse edge interval and multiplied by the time elapsed from the pulse edge.

[0091] Next, in step S1002, the time required from when the motor output signal is turned off until the motor stops is detected. This time corresponds to T2 in Figures 15 and 16. T2 is also shown in Figure 7(C) or Figure 18, and is derived from Figure 9 or Figure 11. FIG. 15 (motor stop starting point 1) shows the case where the motor's current rotation angle is unknown at the timing when it is determined that the motor needs to be stopped. In this case, the timing when the pulse edge is detected is taken as the motor rotation stop starting point. FIG. 16 (motor stop starting point 2) shows the case where the motor's current rotation angle θ is known at the timing when it is determined that the motor needs to be stopped. If the motor's current rotation angle θ is known, that point in time is taken as the motor rotation stop starting point.

[0092] Figure 15 can be said to be a special case in which θ=0 can be confirmed by measuring the pulse edge, and any timing can be used as the stopping starting point as long as θ can be recognized, without being limited to the timings in Figures 15 and 16. The rotation angle during the period T1 is Time rotation angle of T1 = ω × T1 = π × T1 / T0 For ω, the above-mentioned ωavr or ωsgl is used. To find the rotation angle during the period T2, first find the deceleration angular acceleration α. ​​Since the angular velocity becomes 0 during the period T2, ω-α×T2=0 Therefore, α=ω / T2=π / (T0×T2) It becomes. Here, the rotation stop position is estimated from the deceleration of the DC motor, and deceleration control is performed so as to stop the motor at a target rotation angel position. Therefore, the rotation angle of T2 is ω×T2-(1 / 2)α×T2×T2 =(π / T0)×T2-(1 / 2)×(π / (T0×T2))×T2×T2 =(1 / 2)×π×(T2 / T0) The angle at which the angle moves at T1+T2 is π×T1 / T0+(1 / 2)×π×(T2 / T0) This rotation angle should be n×π-θ+(1 / 2)×π, so π×T1 / T0+(1 / 2)×π×(T2 / T0)=n×π-θ+(1 / 2)×π holds true. From this T1=((n×π-θ+(1 / 2)×π)×T0-(1 / 2)×π×T2) / π T1 = (1 / 2) × (T0 - T2)... n = 0, θ = 0 Then T1 can be calculated.

[0093] In the case of the configuration shown in FIG. 15, T1 can be found by substituting θ=0. Next, in step S1004, the lapse of time T1 is detected, and the motor output signal is turned OFF to stop the motor. By implementing the configurations described above, the motor can be stopped midway between pulse edges. [Industrial Applicability]

[0094] In the above embodiment, an electric power seat has been exemplified as the positioning device of the present invention, but the positioning device can also be applied to electric tilt and telescopic steering devices for vehicles, rearview mirrors, side mirrors, etc.

Claims

1. In a positioning device comprising an actuator connected to a moving body and comprising a DC motor, a speed reducing mechanism, and a single-phase rotation sensor for detecting a rotational displacement of the speed reducing mechanism, and an electronic control device for electrically driving the DC motor, the electronic control device comprises: stop control means for controlling deceleration so as to stop the DC motor at a target rotation stop position approximately midway between a rising edge and a falling edge of an output pulse of the rotation sensor; A positioning device comprising a learning control means for learning the target rotation stop position.

2. 2. The positioning device according to claim 1, wherein said stop control means controls the DC motor to decelerate and stop in an inertial rotation mode in which power supply to said DC motor is cut off.

3. 2. The positioning device according to claim 1, wherein said stop control means performs deceleration control so as to decelerate and stop the DC motor in a brake mode in which power supply terminals of said DC motor are electrically short-circuited.

4. 2. The positioning device according to claim 1, wherein said stop control means performs deceleration control so as to decelerate and stop the DC motor by a forced brake mode in which electric power for applying a rotational force in a direction opposite to a direction in which the DC motor rotates during operation is applied to a power supply terminal of the DC motor.

5. The positioning device according to any one of claims 1 to 4, The learning control means Detecting a first timing for generating one of the outputs of the rotation sensor; detecting a second timing longer than the first timing at which the other of the rotation sensor outputs is generated; when one of the outputs of the rotation sensor is detected at a third timing between the first timing and the second timing, the third timing is set as a new first timing; When the other output of the rotation sensor is detected, the third timing is set as a new second timing; A positioning device that learns the target rotation stop position by detecting the output of the rotation sensor at a new third timing between the new first timing or the original first timing and the new second timing or the original second timing.

6. 6. The positioning device of claim 5, A positioning device that repeatedly detects the output of a rotation sensor at a new third timing between the new first timing or the original first timing and the new second timing or the original second timing, and detects and learns an approximately midpoint between the rising edge and the falling edge of the output pulse.

7. 6. The positioning device according to claim 5, wherein the deceleration control is performed in a forced brake mode, A positioning device that learns a forced brake mode period determined by a new third timing between the new first timing or the original first timing and the new second timing or the original second timing.

8. The positioning device according to any one of claims 1 to 4, The learning control means Detecting a first timing for generating one of the outputs of the rotation sensor; detecting a second timing longer than the first timing at which the other of the rotation sensor outputs is generated; When one of the outputs of the rotation sensor is detected at a third timing obtained by adding a predetermined amount to the first timing or subtracting a predetermined amount from the second timing, the third timing is set as a new first timing; When the other output of the rotation sensor is detected, the third timing is set as a new second timing; A positioning device that learns the target rotation stop position by detecting an output of the rotation sensor at a new third timing obtained by adding or subtracting the predetermined amount.

9. 9. The positioning device of claim 8, A positioning device that repeatedly detects the output of the rotation sensor at a new third timing obtained by adding or subtracting the specified amount, and detects and learns an approximately midpoint between the rising edge and the falling edge of the output pulse.

10. 9. The positioning device according to claim 8, wherein the deceleration control in the forced brake mode is A positioning device that learns a forced brake mode period determined by a new third timing obtained by adding or subtracting the predetermined amount.

11. 11. The positioning device according to claim 1, wherein the moving body is an electric power seat for a vehicle.

12. 11. The positioning device according to claim 1, wherein the moving body is an electric tilt / telescopic steering device for a vehicle.

13. A method for controlling a positioning device according to any one of claims 1 to 11.

Images