JP6413166B2 - Reaction force output device - Google Patents

Description

  The present invention relates to a reaction force output device.

In drive motors used for home appliances, medical devices, and the like, a technique for controlling torque output in one direction by performing open-loop control of the motor rotation speed is known (for example, Patent Document 1). 2).
In addition, in order to suppress unintentional sudden acceleration during vehicle start-up or travel, for example, an accelerator pedal that outputs to the accelerator pedal a force (reaction force) in the opposite direction to the force that depresses the accelerator pedal (stepping force) An apparatus is known (see, for example, Patent Document 3).

  The accelerator pedal device described in Patent Document 3 is a housing that pivotally supports the base end of a pedal arm, a return spring for returning the pedal arm to an initial position, a motor for creating a reaction force, A lever for transmitting the rotation of the motor to the pedal arm is incorporated. In this accelerator pedal device, the motor is controlled by the control device to an output corresponding to the depression state of the accelerator pedal, and the output is applied to the pedal arm through the transmission lever.

  The reaction force output device used in an accelerator pedal device or the like is not only for suppressing sudden acceleration, but also when the structure (so-called drive-by-wire) in which the connection between the accelerator pedal and the throttle valve is omitted is adopted. It is also used to give the driver a comfortable treading feeling (accelerator feeling).

JP 2000-295886 A JP-A-6-70586 JP 2010-111379 A

  However, in the conventional motor control device, when a force opposite to the torque output in one direction is applied to the drive motor, a counter electromotive current may be generated inside the motor. Due to this counter electromotive current, the drive motor sometimes outputs a torque larger than the torque output based on a predetermined control amount.

  Further, in the conventional reaction force output device, when the driving motor outputs a force in the reverse direction to the accelerator pedal, there is a case where a counter electromotive current is generated in the motor if a further stepping force is applied. . As a result, the reaction force output device sometimes outputs a reaction force larger than the reaction force to be output.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a reaction force output device that can suppress an excessive output of reaction force during operation. .

The reaction force output device of the present invention employs the following configuration.
(1) A motor having a rotating output shaft and outputting a force acting in a direction opposite to the operation direction to an operator operated by a person by driving a driving member coupled to the output shaft. When the force is the rotational speed of the output shaft in the opposite direction in a direction that is output to determine whether a threshold value or more, the rotation speed of the output shaft in the opposite direction in the direction of the force is outputted If There it is judged less than the threshold value, to control the energization of the drive unit at a duty ratio based on the input value, the rotational speed of the output shaft in the opposite direction in the direction of the force is output over the threshold value Is determined based on the input value and the amount of back electromotive current generated inside the motor by rotating the output shaft in the direction opposite to the direction in which the force is output. and a control unit for controlling the energization of the motor at a duty ratio It was so.
According to such a configuration , the reaction force output device can energize the motor so as to cancel a part or all of the reaction force corresponding to the counter electromotive current generated inside the motor . As a result, the reaction force output device can suppress an excessive output of the reaction force during operation. Therefore, the reaction force output device can improve the feeling of stepping on the accelerator pedal, for example, when the driver steps on the accelerator pedal.

  ADVANTAGE OF THE INVENTION According to this invention, the reaction force output device which can suppress the reaction force output excessively during operation can be provided.

It 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. It is a figure showing an example of an internal structure of reaction force output device 10 concerning one embodiment. It is a figure showing an example of functional composition centering on a control circuit of reaction force output device 10 concerning one embodiment. It is a figure which shows an example of the timing of the process which changes a duty ratio. It is a figure which shows an example of a reference table. It is a figure which shows a mode that the relational expression which shows the correspondence of the duty ratio of a PWM signal, and the rotation speed n of the motor 20 is derived | led-out. It is a flowchart which shows the flow of the process performed by the control circuit of the reaction force output device 10 which concerns on one Embodiment.

  Hereinafter, embodiments of a 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 is provided on a holding base 2a attached to the vehicle body, a pedal arm 4 whose base end is rotatably supported by a support shaft 2b provided on the holding base 2a, and a distal end portion of the pedal arm 4. The holding base 2a is provided with a return spring (not shown) that constantly urges the pedal arm 4 to the initial position.

  A cable (not shown) for operating the opening of a throttle valve (not shown) of the internal combustion engine (engine) is connected to the pedal arm 4 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 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 distal end portion of the output lever 12 that is a driving member of the reaction force output device 10 and the distal end portion 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 the direction opposite to the direction of the pedaling force to the operator.

  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 that is pivotally supported by the housing member 14, a gear reduction mechanism 30, and the like. And a circuit board 50. 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. In addition, a small hole, a slit, or the like is provided in the housing that covers the rotor of the motor 20, and a Hall IC (Integrated Circuit) is fitted into 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 based on the output voltage of the Hall IC. The reaction force output device 10 calculates the rotation speed n based on, for example, the timing interval at which the magnetic flux intensity detected by the Hall IC exceeds a threshold value.

  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 the 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, a microcontroller (microcomputer) 56, a motor driver IC 58, a power FET (Field Effect Transistor). ) 60, Hall IC 64U, 64V, 64W, Hall IC 64, and current detection sensor 66. In the following description, the Hall ICs 64U, 64V, and 64W are collectively referred to as the Hall IC 64 unless otherwise distinguished.

  For example, the host ECU 70 controls the driving of the engine 72 by controlling the opening degree of the throttle valve in accordance with 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 is an example of a “control unit”. 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 an “input value”. For example, a distance (from a predetermined position (for example, a front bumper) of a vehicle on which the reaction force output device 10 is mounted to a vehicle positioned in front of the vehicle ( Hereinafter, it is determined by the host ECU 70 according to “vehicle interval”. The vehicle interval is obtained by, for example, an image sensor or a sound wave sensor installed on the front bumper. For example, when the vehicle interval is shorter than the reference value, the host ECU transmits a reaction force setting value P that outputs a large reaction force to the microcomputer 56. The host ECU 70 may determine the reaction force set value P according to the speed of the vehicle on which the reaction force output device 10 is mounted.

  The microcomputer 56 determines the current command value I 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 I based on a relational expression indicating the relationship between the current command value I and the reaction force set value P, for example. The current command value I is represented, for example, as a current value (for example, the unit is [A]) of the current that is supplied to the motor 20. The microcomputer 56 generates a PWM signal corresponding to the current value, and gives the generated PWM signal to the motor driver IC 58. The PWM signal includes information such as a predetermined voltage value (amplitude value), a duty ratio (pulse width), and a frequency (phase), for example. The motor driver IC 58 performs PWM control on the current supplied to the power FET 60 based on the PWM signal given by the microcomputer 56 to rotate the motor 20. The microcomputer 56 uses the current command value I as a control target value, and performs, for example, PI control (Proportional-Integral Controller) on the control target value.

  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 coil of a corresponding phase 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.

  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 current detected by the current detection sensor 66. 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 determines a current command value I to be given to the motor driver IC 58 based on the detected rotation speed n of the motor 20.

  When the reaction force output device 10 outputs a reaction force, when a pedaling force is applied by the driver, that is, when the motor 20 rotates in a direction opposite to the reaction force output direction, A counter electromotive current may occur. This back electromotive current is particularly large when a pedaling force greater than the reaction force output by the reaction force output device 10 is applied, or when a pedaling force is applied while outputting a large reaction force. There is a tendency to occur as current. As a result, in the reaction force output device 10 according to the present embodiment, a reaction force larger than the originally assumed reaction force may be output due to the counter electromotive current generated in the motor 20.

  Therefore, the reaction force output device 10 in the present embodiment considers the counter electromotive current generated in the motor 20 and sets a duty ratio corresponding to the current command value I so as to reduce the amount of current corresponding to the counter electromotive current. The value is changed based on the rotation speed n of the motor 20.

FIG. 4 is a diagram illustrating an example of processing timing for changing the duty ratio.
The microcomputer 56 determines whether or not the rotation number n of the motor 20 when rotating in the direction opposite to the reaction force output direction is equal to or greater than a threshold value Th as a condition for generating the counter electromotive current. When the rotation speed n is equal to or greater than the threshold Th, a current command value I is given to the motor driver IC 58 based on the rotation speed n of the motor 20. That is, the microcomputer 56 provides the motor driver IC 58 with a PWM signal having a duty ratio based on the rotational speed n of the motor 20 when the rotational speed n of the motor 20 is equal to or greater than the threshold Th. Hereinafter, the rotation speed n of the motor 20 when rotating in the direction opposite to the reaction force output direction will be simply described as “the rotation speed n of the motor 20”.

  The threshold value Th is, for example, the value of the rotational speed n that becomes a boundary on whether or not a counter electromotive current is remarkably generated in the motor 20 when a pedaling force is applied to the motor 20 that outputs a reaction force. Set to In the present embodiment, the threshold value Th that is set to the value of the rotational speed n of the motor 20 is one, but is not limited thereto, and may be set to a plurality of rotational speeds n, for example. The threshold Th may have a certain width in consideration of errors and the like.

  For example, the microcomputer 56 performs a duty ratio changing process during the period from the time t1 to the time t2 and the period from the time t3 to the time t4, in which the rotation speed n of the motor 20 is greater than or equal to the threshold Th. During these two periods, the microcomputer 56 changes the duty ratio of the PWM signal based on the rotation speed n of the motor 20 and the reference table, and provides the motor driver IC 58 with the PWM signal having the changed duty ratio. The reference table is information indicating a correspondence relationship between the duty ratio of the PWM signal and the rotation speed n of the motor 20.

FIG. 5 is a diagram illustrating an example of a reference table.
The reference table is set for each of a plurality of current command values I (current values) set based on the reaction force setting value P, for example. In the reference table corresponding to each current command value I, the duty ratio of the PWM signal and the rotation speed n of the motor 20 are associated with each other. Each reference table is set in association with the rotational speed n of the motor 20 in a predetermined change range (for example, 10 to 50%) based on a duty ratio (for example, 50%) based on the reaction force setting value P. This predetermined change range is set based on the relationship between the amount of current decrease due to the decrease in the duty ratio and the amount of back electromotive current generated inside the motor 20. The predetermined change range is set so that, for example, when the maximum amount of back electromotive current derived in advance by experiment, simulation, or the like is 1 A, the amount of 1 A can be reduced.

  Further, the microcomputer 56 sets the current command value I based on the relational expression indicating the correspondence between the duty ratio of the PWM signal and the rotation speed n of the motor 20 instead of changing the duty ratio based on the reference table. The duty ratio may be derived and changed.

FIG. 6 is a diagram illustrating a state in which a relational expression indicating a correspondence relationship between the duty ratio of the PWM signal and the rotation speed n of the motor 20 is derived.
The microcomputer 56 derives the duty ratio of the PWM signal using a relational expression that realizes the relation shown in FIG. The relational expression is, for example, the measured rotation speed n of the motor 20 and the PWM given to the motor driver IC 58 in an experiment performed by determining the duty ratio of the PWM signal so as not to make the influence of the counter electromotive force feel in advance. By performing statistical processing such as the least square method on the data indicating the relationship with the duty ratio of the signal, an optimum approximate curve LN1 (for example, a linear function) indicating the duty ratio of the PWM signal is derived. For example, when the approximate curve LN1 is an equation such as LN1 = a × n + b, the equation, the coefficient a of the rotation speed n, and the constant term b considering the influence of disturbance etc. are stored in advance in a storage device (not shown). Keep it. The microcomputer 56 derives the duty ratio based on the rotational speed n of the motor 20 acquired during the duty ratio changing process, the coefficient a, the constant term b, and the mathematical formula stored in the storage device, and the duty ratio of the PWM signal Is changed to the derived duty ratio.

  FIG. 7 is a flowchart showing a flow of processing executed by the control circuit of the reaction force output device 10 according to the embodiment. The processing of this flowchart is repeatedly executed at a predetermined cycle, for example.

  First, the microcomputer 56 determines whether or not the reaction force set value P has been received from the host ECU (step S100). When the reaction force output device 10 does not receive the reaction force setting value P from the host ECU (step S100: No), the routine of this flowchart is terminated.

  When the microcomputer 56 receives the reaction force setting value P from the host ECU (step S100: Yes), the microcomputer 56 determines a current command value I based on the reaction force setting value P (step S102). Next, the microcomputer 56 generates a PWM signal based on the current command value I (step S104). Next, the microcomputer 56 gives the generated PWM signal to the motor driver IC 58, performs PWM control on the current to be supplied to the power FET 60, and rotates the motor 20 (step S106).

  Next, the microcomputer 56 determines whether or not the rotational speed n of the motor 20 is equal to or greater than a threshold value Th (step S108). When the rotational speed n of the motor 20 is equal to or less than the threshold Th (step S108: No), the reaction force output device 10 ends one routine of this flowchart. When the rotational speed n of the motor 20 is equal to or greater than the threshold Th (step S108: Yes), the microcomputer 56 changes the duty ratio of the PWM signal based on the rotational speed n of the motor 20 (step S110). Next, the microcomputer 56 provides the PWM signal with the changed duty ratio to the motor driver IC 58, performs PWM control on the current to be supplied to the power FET 60, and rotates the motor 20 (step S112). Thereby, the reaction force output apparatus 10 ends one routine of this flowchart.

  As described above, according to the reaction force output device 10 according to the present embodiment, when the rotational speed n of the motor 20 does not exceed the threshold value Th, the motor 20 is energized with a duty ratio based on the reaction force setting value P. When the rotational speed n of the motor 20 exceeds the threshold Th, the energization to the motor 20 is controlled with a duty ratio corresponding to the rotational speed n of the motor 20. Accordingly, the reaction force output device 10 can energize the motor 20 so as to cancel a part or all of the reaction force corresponding to the counter electromotive current generated in the motor 20. As a result, the reaction force output device 10 can suppress excessive reaction force output during operation.

  Further, the reaction force output device 10 according to the present embodiment can perform control with better responsiveness because the control amount when the motor 20 is energized becomes small.

  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 ... Accel pedal apparatus, 2 ... Pedal main body unit, 6 ... Pedal main body part, 10 ... Reaction force output device, 20 ... Motor, 30 ... Gear reduction mechanism, 50 ... Circuit board, 56 ... Microcomputer, 58 ... Motor driver IC, 70: host ECU, 72 ... engine

Claims (1)

A motor that has a rotating output shaft and outputs a force acting in a direction opposite to the operation direction on an operator operated by a person by driving a drive member coupled to the output shaft;
Determining whether the rotational speed of the output shaft in the direction opposite to the direction in which the force is output is equal to or greater than a threshold;
If the rotational speed of the output shaft in the opposite direction in the direction of the force is outputted is determined to be less than the threshold value, to control the energization of the drive unit at a duty ratio based on the input value,
If the rotational speed of the output shaft in the opposite direction in the direction of the force is outputted is equal to or more than the threshold value, and the input value, the output shaft is rotated in the direction opposite to the direction in which the force is output A controller that controls energization of the motor at a duty ratio determined based on the amount of back electromotive current generated inside the motor ,
Reaction force output device comprising.

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