WO2016140255A1

WO2016140255A1 - Motor control device and reaction-force output device

Info

Publication number: WO2016140255A1
Application number: PCT/JP2016/056392
Authority: WO
Inventors: 隆志大場
Original assignee: 株式会社ホンダロック
Priority date: 2015-03-04
Filing date: 2016-03-02
Publication date: 2016-09-09
Also published as: JP2016163483A

Abstract

A motor control device equipped with a current detection unit for detecting a current that flows into a motor, and a control unit for causing the current detection unit to detect the current at an intermediate point in time between first and second reference values in a pulse signal inputted into a motor driver IC for driving the motor.

Description

Motor control device and reaction force output device

The present invention relates to a motor control device and a reaction force output device.
This application claims priority based on Japanese Patent Application No. 2015-042293 for which it applied on March 4, 2015, and uses the content here.

In order to suppress unintentional sudden acceleration when the vehicle starts or travels, for example, an accelerator pedal device that outputs a force (reaction force) in the opposite direction to the force (depression force) to depress the accelerator pedal is output to the accelerator pedal. Known (see, for example, Patent Documents 1 and 2).

The accelerator pedal device described in

Patent Literatures

1 and 2 includes a housing for pivotally supporting the base end of the pedal arm, a return spring for returning the pedal arm to an initial position, and a motor for generating a reaction force. And a lever for transmitting the rotation of the motor to the pedal arm. In this accelerator pedal device, the control device compares the target current value with the current value consumed by the motor detected by the current detection circuit, performs feedback control, and controls the driving of the motor to a desired state. Thus, the accelerator pedal device is controlled to an output corresponding to the depressed state of the accelerator pedal, and the output is applied to the pedal arm through the transmission lever.

Such a reaction force output device not only suppresses sudden acceleration, but also adopts a structure in which the connection between the accelerator pedal and the throttle valve is omitted (so-called drive-by-wire), the natural pedaling comfort of the accelerator pedal ( It is also used to give the driver an accelerator feeling).

Japanese Unexamined Patent Publication No. 2012-116355 Japanese Unexamined Patent Publication No. 2012-171475

However, in the conventional motor control device, the sampling point of the current value detected by the current detection circuit may not be appropriate. As a result, when feedback control is performed based on the current value detected at the sampling point and the target current value applied to the reaction force output device, and the motor drive is controlled, the motor drive is brought to a desired state. In some cases, the motor cannot be controlled and the motor drive member cannot sufficiently follow the pedal arm.

The aspect which concerns on this invention was made | formed in view of such a situation, and it aims at providing the motor control apparatus and reaction force output apparatus which can detect an electric current value at a desired sampling point. .

In order to solve the above technical problems and achieve the object, the present invention adopts the following aspects.
(1) A motor control device according to an aspect of the present invention includes a current detection unit that detects a current flowing into a motor, a first reference value and a first reference value in a pulse signal input to a motor driver IC that drives the motor. And a control unit that causes the current detection unit to detect the current at a time point intermediate to the reference value of 2.

(2) In the aspect of (1), the control unit counts the intermediate time point between the first reference value and the second reference value in the pulse signal and a preset time width. A target number of times for executing the delay counter may be calculated based on a counter, and the current detection unit may detect the current when the delay counter is executed for the target number of times.

(3) In the above aspect (2), the control unit may calculate the target number of times by performing a shift operation.

(4) In the aspect of (2) or (3), the control unit waits for another interrupt process until the delay counter is executed for the target number of times, and the delay counter is executed for the target number of times. After that, the other interrupt processing that has been in the standby state may be executed.

(5) The reaction force output device according to one aspect of the present invention is an operation that is operated by a person by driving any one of the motor control devices (1) to (4) and the driving member. A driving unit that outputs a force in a direction opposite to the operation direction to the child and the motor that outputs a driving force for driving the driving unit are provided.

According to the aspect of the present invention, the followability of the driving member driven by the motor with respect to the pedal arm can be improved by detecting the current supplied to the motor at a desired sampling point.

The figure which shows an example of the external appearance structure of an accelerator pedal apparatus provided with the reaction force output device which concerns on one Embodiment. The figure which shows an example of the internal structure of the reaction force output device which concerns on one Embodiment. The figure which shows an example of the function structure centering on the control circuit of the reaction force output device which concerns on one Embodiment. The flowchart which shows the flow of the process which a microcomputer performs. The conceptual diagram for demonstrating the process which a microcomputer performs. The figure which shows an example of the general method in the case of detecting an electric current value. The figure for demonstrating the sampling point which detects the electric current value when the duty ratio of the PWM signal in a general method is changed.

Hereinafter, embodiments of the motor control device and the reaction force output device of the present invention will be described with reference to the drawings. A reaction force output device according to an embodiment outputs, for example, a force (reaction force) opposite to a stepping force (stepping force) to an operator such as an accelerator pedal provided for instructing acceleration of the vehicle. Device. By using the reaction force output device, it is possible to improve the accelerator feeling, to transmit the accelerator work that saves fuel consumption, and to perform various safety controls. Safety control includes control that outputs a relatively large reaction force in order to suppress excessive acceleration before a curve, in an urban area, a school zone, or the like. In addition, when the accelerator pedal is simply operated exceeding the reference, it may be determined that the operation is erroneous and control to output a large reaction force may be performed. In addition, the operation element that is the reaction force output target in the present embodiment is not limited to the accelerator pedal, and may be a brake pedal, a steering wheel, an operation device of a game machine, or the like.

Drawing 1 is a figure showing an example of the appearance composition of accelerator pedal device 1 provided with reaction force output device 10 concerning one embodiment.
The accelerator pedal device 1 includes a pedal body unit 2 installed in front of the driver's seat and a reaction force output device 10 installed above the pedal body unit 2.

The pedal body unit 2 includes a holding base 2a attached to the vehicle body, a pedal arm 4 (operator) whose base end is rotatably supported by a support shaft 2b provided on the holding base 2a, and a distal end of the pedal arm 4. Provided with a pedal body 6 (operator) to which the driver applies pedaling force, and the holding base 2a is provided with a return spring (not shown) that constantly urges the pedal arm 4 to the initial position. It has been.

Connected to the pedal arm 4 is a cable (not shown) for operating the opening of a throttle valve (not shown) of the internal combustion engine (engine) in accordance with the operation amount (rotation angle) of the pedal arm 4. . However, when the internal combustion engine employs an electronically controlled throttle, a rotation sensor for detecting the rotation angle of the pedal arm 4 is provided in the pedal body unit 2, and the throttle valve is detected based on the detection signal of the rotation sensor. The opening degree may be controlled. Further, a reaction force transmission lever 8 (operator) extending in a direction substantially opposite to the extending direction of the pedal arm 4 is integrally connected to the vicinity of the base end of the pedal arm 4.

Further, the tip of the output lever 12 that is a driving member of the reaction force output device 10 and the tip of the reaction force transmission lever 8 can be brought into contact with each other. The turning force of the output lever 12 that is a drive member of the reaction force output device 10 is output to the pedal arm 4 via the reaction force transmission lever 8. In this way, the reaction force output device 10 outputs a reaction force in a direction opposite to the direction of the pedal force to the operation element (for example, the reaction force transmission lever 8).

FIG. 2 is a diagram illustrating an example of the internal structure of the reaction force output device 10 according to an embodiment. In FIG. 2, the cover of the upper surface of the housing member 14 is removed, and the internal state of the housing member 14 (reaction force output device 10) is shown. The reaction force output device 10 according to the present embodiment includes a motor 20 that is a drive source for creating a reaction force, a reaction force output shaft 16 (drive unit) that is pivotally supported by the housing member 14, and a gear reduction. A mechanism 30 (drive unit) and a circuit board 50 are provided. The gear reduction mechanism 30 decelerates the rotation of the rotor of the motor 20 and increases the torque T output from the motor 20 side, and increases the torque T by deflecting from the motor rotation shaft 22 direction to the reaction force output shaft 16 direction. T is transmitted to the output lever 12. One end portion in the reaction force output shaft direction protrudes outward from the side surface of the housing member 14, and the output lever 12 is integrally connected to the protruding end portion.

The rotation of the rotor of the motor 20 is controlled by a control circuit mounted on the circuit board 50. Connected to the circuit board 50 is a CAN (Controller Area Network) cable (not shown) for transmitting and receiving signals between a host ECU (Electronic Control Unit) described later and a control circuit. The circuit board 50 and the motor 20 are connected via a cable (not shown), and the rotation of the rotor of the motor 20 is controlled based on a control signal sent from the circuit board 50. Further, a small hole, a slit, or the like is provided in the casing that covers the rotor of the motor 20, and a Hall IC (Integrated Circuit) is fitted and installed in the small hole, the slit, or the like. The Hall IC detects the magnetic flux intensity that passes through a small hole, a slit, or the like, and outputs a pulsed voltage corresponding to the detected magnetic flux intensity. The magnetic flux intensity detected by the Hall IC changes according to the rotation of the rotor in the motor 20. For this reason, the reaction force output device 10 can detect the rotation amount of the rotor (for example, the rotation speed n [rpm]) based on the output voltage of the Hall IC.

FIG. 3 is a diagram illustrating an example of a functional configuration centering on a control circuit of the reaction force output device 10 according to an embodiment. In FIG. 3, the reaction force output device 10 includes a CAN control circuit 54 that performs CAN communication between the motor 20 and the host ECU 70, a microcontroller (microcomputer) 56 (control unit), a motor driver IC 58, and a power FET. (Field Effect Transistor) 60,

Hall ICs

64U, 64V, 64W, and a current detection sensor 66 (current detection unit).

The current detection sensor 66 and the microcomputer 56 are motor control devices that determine a current command value that is a control amount to be given to the motor driver IC 58. In the following description,

Hall ICs

64U, 64V, and 64W are collectively referred to as Hall IC 64 unless otherwise distinguished.

The host ECU 70 controls the driving of the engine 72 by controlling, for example, the opening degree of the throttle valve according to the operation amount of the pedal arm 4. In the engine 72, a crankshaft as an output shaft is connected to an axle, and outputs a driving force for driving the vehicle. The travel drive unit may have a configuration in which a travel motor is added to the engine 72, or may have a configuration in which the travel drive force is output only by the travel motor without the engine 72.

The microcomputer 56 performs CAN communication with the host ECU 70 via the CAN control circuit 54. The microcomputer 56 receives a reaction force set value P, which is a reference for the magnitude of the reaction force generated by the reaction force output device 10, from the host ECU 70. The reaction force set value P is an example of “input value”. For example, the reaction force set value P may be determined so as to increase according to the vehicle speed of the vehicle on which the reaction force output device 10 is mounted, or in order to suppress a sudden accelerator operation in order to improve fuel efficiency. It may be determined. Further, the reaction force setting value P may be determined so as to increase as the distance between the vehicle on which the reaction force output device 10 is mounted and the preceding vehicle becomes shorter. The inter-vehicle distance is acquired by, for example, a millimeter wave radar or a sound wave sensor installed at the front portion of the vehicle, a stereo camera device installed at the top of the windshield, or the like. For the application of the present invention, there is no particular limitation on the method for determining the reaction force set value P.

The microcomputer 56 determines a current command value as a control amount to be given to the motor driver IC 58 based on the reaction force set value P. At this time, the microcomputer 56 determines the current command value based on a relational expression indicating the relationship between the current command value and the reaction force set value P, for example. The motor driver IC 58 determines a pulse width, a duty ratio, and the like at the time of PWM control based on the current command value, controls a current to be supplied to the power FET 60, and rotates the motor 20.

The microcomputer 56 is connected to a current detection sensor 66 for detecting a current supplied to the motor 20 and a motor driver IC 58. The microcomputer 56 receives a signal indicating the detection value detected by the current detection sensor 66. The microcomputer 56 determines a current command value to be given to the motor driver IC 58 based on the signal indicating the detection value detected by the current detection sensor 66 and the rotation speed n of the motor 20 calculated from the signal output from the motor driver IC 58. Details of processing executed by the microcomputer 56 will be described later.

The power FET 60 includes U-phase, V-phase, and W-

phase power FETs

60U, 60V, and 60W, and each power FET is connected to a corresponding phase coil of the motor 20, respectively. The motor driver IC 58 cyclically turns on / off each phase power FET to generate a magnetic field in each phase coil, and rotates the rotor of the motor 20.

In addition to the microcomputer 56, three

Hall ICs

64U, 64V, 64W are connected to the input terminal of the motor driver IC 58, and the motor driver IC 58 accepts a change in voltage output from each of the

Hall ICs

64U, 64V, 64W. The motor driver IC 58 outputs a signal indicating the rotational speed n of the motor 20 to the microcomputer 56 based on the input from the

Hall ICs

64U, 64V, 64W. Thereby, the microcomputer 56 detects the rotation speed n of the motor 20.

The microcomputer 56 acquires the detection value output from the current detection sensor 66 as an analog quantity, and derives the current value supplied to the motor 20 by quantizing the acquired analog quantity.
The current detection sensor 66 detects a current flowing out from the power FET unit 60. This current is equivalent to the current flowing into the motor 20. The current detection sensor 66 detects a current flowing out from the power FET unit 60 by measuring a potential difference between the AD terminal side and the ground line side and converting the measured voltage into a current value by adding an internal resistance. The microcomputer 56 uses a relational expression or a data table showing a relation between a preset detection value of the current detection sensor 66 and a current value consumed by the motor 20 with respect to the detection value output by the current detection sensor 66. Apply to derive the current value consumed by the motor 20.

FIG. 4 is a flowchart showing a flow of processing executed by the microcomputer 56. First, the microcomputer 56 acquires the High setting time in the PWM signal for controlling the current command value given to the motor driver IC 58 (step S100). Next, the microcomputer 56 calculates an intermediate time point of the High set time in the PWM signal (step S102). The intermediate time point is calculated by dividing the High set time in the PWM signal by 2, for example.

Next, the microcomputer 56 calculates the number n of increments of the delay counter between the start time of the high setting and the intermediate point (step S104). The delay counter is a counter for counting a preset time width (delay time). When the delay counter is executed once, a preset time width is counted. The delay time of the delay counter is, for example, 510 ns. The number of increments is calculated by the time from the high setting start time to the intermediate time / the time width of the delay counter. That is, in step S106, the number of times (target number of times) that the delay counter necessary to reach the intermediate time point is executed is calculated.

Next, the microcomputer 56 performs a process of executing the delay counter once (step S106). When one delay counter is executed by the microcomputer 56, the delay time is counted. Next, the microcomputer 56 determines whether or not the increment number n calculated in step S104 and the delay counter (i) have been executed (step S108). If the delay counter has not been executed for the increment number n calculated in step S104, the microcomputer 56 returns to the process of step S106 and performs the process of executing the delay counter. When the delay counter is executed for the increment number n calculated in step S104, the microcomputer 56 causes the current detection sensor 66 to detect the current supplied to the motor 20 (step S110). Thereby, the processing of this flowchart is completed. As described above, the microcomputer 56 repeatedly executes the delay counter up to the intermediate point, and then detects the current that is supplied to the motor 20 through the current detection sensor 66. Therefore, even if the High time of the PWM signal is variable, As will be described later (FIGS. 6 and 7), the current value at the intermediate point of the High time of the PWM signal can be detected.

Note that the processing of the flowchart described above may be executed using a shift operation. For example, the microcomputer 56 acquires the High setting time in the PWM signal indicated by a binary number, a quaternary number, a hexadecimal number, or the like (step S102), and calculates the increment number of the delay counter corresponding to the intermediate point of the acquired High setting time. A shift calculation is performed (step S104). For example, the intermediate time point of the High set time is calculated from the High set time (hexadecimal number) / 2 in the PWM signal. Further, the number of executions of the delay counter is calculated based on the calculated intermediate time / 16. Thus, the processing load of the microcomputer 56 can be reduced by calculating the number of executions of the delay counter by the shift operation and executing the delay counter process based on the calculated result.

Further, the microcomputer 56 puts other interrupt processing into a standby state while the processing for detecting the current value using the delay counter is being executed. The microcomputer 56 sequentially executes the interrupt process in the standby state based on the priority order associated with the process after the process of executing the delay counter n times is performed. Thereby, the microcomputer 56 can acquire the electric current value in the intermediate | middle time P in the High setting time of a PWM signal. If another interrupt process is being executed, the microcomputer 56 temporarily stops the execution of the other interrupt process and executes the process of detecting the current value using the delay counter in preference to the other interrupt process. May be. In this case, similarly, the microcomputer 56 executes another interrupt process that has been stopped after executing the process of detecting the current value using the delay counter.

FIG. 5 is a conceptual diagram for explaining processing executed by the microcomputer 56. As an example, a case will be described in which the microcomputer 56 performs the processing executed in the above-described flowchart in the state of the PWM signal shown in FIG. 5 and the voltage waveform of the AD terminal input. First, the microcomputer 56 acquires the High set time T in the PWM signal, and calculates an intermediate time point P of the High set time T. The rising edge of the High set time T is the first reference value, and the falling edge is the second reference value. The microcomputer 56 calculates the number n of times that the delay counter is incremented between the start time of High setting and the intermediate point P. The microcomputer 56 reaches the intermediate time point P by performing a process of executing from the delay counter 1 to the delay counter n. The microcomputer 56 causes the current detection sensor 66 to detect the voltage value applied to the motor 20 when the intermediate point P is reached. Thereby, the current detection sensor 66 detects the voltage value P * at the intermediate time point P in the High set time. As a result, the microcomputer 56 can acquire a voltage value near an intermediate point in the waveform of the voltage applied to the motor 20. Further, the microcomputer 56 can determine the current command value as a control amount to be given to the motor driver IC 58 by acquiring the voltage value P * at the intermediate time point P and converting the acquired voltage value into a current value. Therefore, the motor 20 can be controlled with higher accuracy.

Until now, it has been difficult to detect the current value at the intermediate point (desired sampling point) in the High setting time. FIG. 6 is a diagram illustrating an example of a general technique in detecting a current value. The waveforms in the figure are a motor current waveform energized by the motor 20, an AD terminal input waveform, an AD conversion processing waveform, and a PWM signal waveform input to the motor driver IC. The rising edge of the pulse in the AD conversion processing waveform indicates the timing at which the current detection sensor 66 detects the current value. The measurement conditions are a peak current value of 3 [A], a power supply voltage of 13.5 [V], and the motor mode is a state where the output shaft is fixed. When the motor 20 is energized in the section where the PWN signal is High (H in the figure), the current fall due to the power FET being turned off becomes very steep when not passing through the low-pass filter. For this reason, it is difficult to detect the current at the time of falling. Further, when the current supplied to the motor 20 is detected when the falling time has elapsed, the current value is supplied to the motor 20 despite the current being supplied to the motor 20 due to a delay in transmission caused by hardware or software. May be detected as zero.

In addition, when detecting the current value at the rising edge of the PWM signal, a delay occurs depending on the processing time as shown in the figure. Therefore, the point for detecting the current value is after the processing time has elapsed from the rising edge of the PWM signal. In this case, the time for detecting the current value can be fixed after the delay time has elapsed. For example, the point at which the current value is detected can be fixed at a predetermined time after the rise of the PWM signal (P1 in the figure). In this case, when the duty ratio of the PWM signal is changed, the sampling point for detecting a fixed current value in the PWM signal may be the beginning or end of the section where the PWM signal is High due to the duty ratio. There is.

FIG. 7 is a diagram for explaining sampling points for detecting a current value when the duty ratio of the PWM signal is changed in a general method. FIG. 7 shows a PWM signal, an AD terminal input voltage waveform, and a fixed sampling point for sampling a current value. The sampling points in the left figure ex1 and the right figure ex2 are the same.
The left diagram ex1 shows a case where the High interval of the PWM signal is longer than the High interval of the PWM signal of the right diagram ex2. When the High period of the PWM signal shown in the left diagram ex1 is long, the desired sampling point is the initial of the High period of the PWM signal regardless of the intermediate point P2 of the High period of the PWM signal, and the motor 20 is energized. The current value tends to be detected lower than the average current. On the other hand, as shown in the right diagram ex2, when the High period of the PWM signal is short, the sampling point is High of the PWM signal regardless of the current sampling point P3 near the intermediate point in the High period of the PWM signal. In the latter half of the section, the current value tends to be detected higher than the average current supplied to the motor 20. As described above, when the point at which the current value is sampled is fixed, the current value cannot be detected at a desired sampling point due to the change in the duty ratio of the PWM signal, and an inappropriate current value may be detected. As a result, the drive of the motor 20 may change suddenly.

On the other hand, in the present embodiment, as described with reference to FIG. 5 described above, the microcomputer 56 executes the current when the delay counter is executed a predetermined number of times according to the set time of the High section of the PWM signal. Sample the value. Thereby, the microcomputer 56 can detect the current value at the intermediate point in the High period of the PWM signal. Thereby, it is possible to set a more appropriate sampling point and detect the current value in the transition of the current value accompanying the change of the PWM signal. As a result, the current command value can be determined with higher accuracy, and the drive of the motor 20 can be smoothly changed. Moreover, the accelerator feeling given to the driver | operator of the accelerator pedal apparatus 1 to which the reaction force output device 10 was applied can be improved.

For example, depending on the specifications of the microcomputer 56 or the power FET unit 60, the PWM signal may fall when the PWM signal becomes High, and the PWM signal may rise when the PWM signal becomes Low. In this case, the processing by the microcomputer 56 of this embodiment can be applied assuming that the PWM signal is High when the PWM signal is falling. In the present embodiment, the desired sampling point is set to the intermediate point of the High set time, but the desired sampling point may be changed as appropriate. In this case, the microcomputer 56 executes the delay counter until the time corresponding to the desired sampling point, and after executing the delay counter, causes the current detection unit 66 to detect the current value.

As described above, according to the motor control device of the present embodiment, the pulses input to the current detection unit 66 (56) that detects the current flowing into the motor 20 and the motor driver IC (58) that drives the motor. By including a control unit 56 that causes the current detection unit to detect a current at an intermediate time between the first reference value and the second reference value in the signal, the current supplied to the motor 20 is detected at a desired sampling point. be able to. As a result, since the microcomputer 56 performs feedback control based on the detected current value and determines a new current command value, it is possible to provide a motor control device that can improve followability.

As mentioned above, although the form for implementing this invention was demonstrated using embodiment, this invention is not limited to such embodiment at all, In the range which does not deviate from the summary of this invention, various deformation | transformation and substitution Can be added.

DESCRIPTION OF SYMBOLS 1 ... Accelerator pedal apparatus, 2 ... Pedal main body unit, 6 ... Pedal main body part, 10 ... Reaction force output device, 12 ... Output lever, 20 ... Motor, 56 ... Microcomputer (control part), 66 ... Current detection sensor

Claims

A current detector for detecting the current flowing into the motor;
A control unit that causes the current detection unit to detect the current at an intermediate time point between a first reference value and a second reference value in a pulse signal input to a motor driver IC that drives the motor;
A motor control device comprising:
The control unit executes the delay counter based on the intermediate time point between the first reference value and the second reference value in the pulse signal and a delay counter that counts a preset time width. Calculating the target number of times, and causing the current detection unit to detect the current when the delay counter is executed the target number of times;
The motor control device according to claim 1.
The control unit calculates the target number of times by performing a shift operation.
The motor control device according to claim 2.
The control unit sets another interrupt process in a standby state until the delay counter is executed for the target number of times, and executes the other interrupt process in the standby state after the delay counter is executed for the target number of times. Let
The motor control device according to claim 2 or claim 3.
The motor control device according to any one of claims 1 to 4,
A driving unit that outputs a force in a direction opposite to the operation direction with respect to an operator operated by a person by driving the driving member;
The motor for outputting a driving force for driving the driving unit;
Reaction force output device comprising.