JP4908096B2 - Control device and actuator control device - Google Patents

Description

  The present invention relates to a control device and an actuator control device.

  As this type of actuator that forms part of the drive system, for example, a transmission member that is a feed screw mechanism including a ball screw nut and a screw shaft that is rotatably engaged with the ball screw nut, and a screw shaft For example, when the driven member is an unsprung member or unsprung member in a vehicle, the drive system is a suspension device. .

  Hereinafter, the actuator will be described in detail. As this type of actuator, for example, a cylinder connected to one of a sprung member or an unsprung member of a vehicle, a ball screw nut fixed in the cylinder, and a ball screw nut A screw shaft that is rotatably screwed and a motor that has a rotor connected to the screw shaft and that is connected to the other of the sprung member or the unsprung member, and is configured to control the rotational movement of the screw shaft. By converting the axial movement of the screw shaft and the cylinder by the screw nut and the feed screw mechanism, the torque generated by the motor can be used for suppressing or assisting the relative movement. .

Further, the actuator control device can control the motor by PWM (Pulse Width Modulation) to make the load generated by the actuator (damping force) variable (see, for example, Patent Document 1).
JP 2003-343647 A

なお、式（１）中、ｆｍはロータの機械的な共振周波数であり、Ｋはロータに連結される部材全体の捩りバネ定数、Ｉはロータの慣性モーメントをそれぞれ示している。 By the way, in the above actuator, since the rotor of the motor is connected to the screw shaft, and the screw shaft is rotatably connected to the cylinder via the screw nut, the mechanical of the rotor is adopted. The resonance frequency of the rotor, that is, the resonance frequency in the circumferential vibration of the rotor, as shown in the following formula (1), is the moment of inertia of the rotor and the whole member connected to the rotor, in this case, mainly the screw shaft, It is determined by the torsion spring constant (circumferential torsional rigidity) of the torsion bar and the entire cylinder.

In Equation (1), fm is the mechanical resonance frequency of the rotor, K is the torsion spring constant of the entire member connected to the rotor, and I is the inertia moment of the rotor.

  On the other hand, in the control device for PWM control of the motor, the current flowing through the winding is controlled based on the voltage command value applied to the plurality of windings of the motor's armature. A voltage higher than the power supply voltage cannot be applied. Therefore, when the voltage command value to be applied to the winding exceeds the power supply voltage, the voltage command value is saturated, and the motor cannot be normally controlled.

なお、式（２）中、ｆｅはモータの電気的な共振周波数であり、Ｒは巻線のレジスタンス、Ｌは巻線のインダクタンス、ωはロータの電気角速度をそれぞれ示している。 In such a state, it is difficult to control the current flowing through each winding, and a phenomenon in which the current flowing through the winding resonates appears. The frequency at which the current flowing through the winding resonates, that is, the electrical resonance frequency of the motor, changes according to the rotational speed of the rotor proportional to the stroke speed of the actuator, as shown in the following equation (2). It will be.

In equation (2), fe is the electrical resonance frequency of the motor, R is the resistance of the winding, L is the inductance of the winding, and ω is the electrical angular velocity of the rotor.

  As can be understood from the above equation (2), the electrical resonance frequency of the motor has a property of increasing as the rotational speed of the rotor increases.

Therefore, in the conventional actuator, a vibration mode that oscillates when the electrical resonance frequency that changes according to the rotational speed of the rotor approaches the mechanical resonance frequency of the rotor described above, resulting in generation of the motor. The torque ripple increases, and the stroke speed becomes unstable and vibrates . As shown in FIG. 8, such a phenomenon does not appear on the side of assisting the stroke of the actuator but appears only when the stroke is suppressed, and the electric resonance frequency of the motor is the rotational speed of the rotor (actuator The above vibration mode appears when the rotor speed increases to near the mechanical resonance frequency of the rotor, and when the rotor rotational speed (actuator stroke speed) increases, the motor's electrical resonance The frequency goes over the mechanical resonance frequency of the rotor and shifts to the right in the figure to move away from the mechanical resonance frequency of the rotor, and this vibration mode does not appear.

  Therefore, the present invention was devised to improve the above-described problems, and the object of the present invention is to provide a control device capable of preventing the occurrence of a vibration mode in which the vibration of the rotor in the motor is excited. And an actuator control device.

In order to achieve the above-described object, the control device in the problem solving means of the present invention is configured such that the motor is connected to the driven member via a transmission member interposed between the driven member driven by the motor and the rotor of the motor. A control device for controlling a motor in a drive system for transmitting power, wherein a predetermined electric angular velocity is smaller than an electric angular velocity region that excites a circumferential vibration of a rotor that acts as a moment of inertia when a voltage command value is saturated. and angular velocity, when the electrical angular velocity of the rotor is equal to or more than the predetermined electrical angular speed, to control the motor voltage command value as zero.

In order to achieve the above-described object, the actuator control apparatus in the problem solving means of the present invention includes a linear motion member and a rotation member, and a motion conversion mechanism that converts linear motion of the linear motion member into rotational motion of the rotation member; And an actuator control device including a motor having a rotor coupled to a rotating member, and an electric motor that excites a circumferential vibration of the rotor that acts as a moment of inertia when a voltage command value is saturated at a predetermined electrical angular velocity. and less electrical angular velocity than the region of the angular velocity, when the electrical angular velocity of the rotor is equal to or more than the predetermined electrical angular velocity, and controlling the motor voltage command value as zero.

  According to the actuator control device of the present invention, the increase in the electrical angular velocity of the rotor causes the motor's electrical resonance frequency to approach the resonance frequency in the circumferential vibration of the rotor and develop a vibration mode. It becomes possible to prevent the vibration mode from appearing by setting the command value to zero.

  Therefore, the occurrence of a vibration mode in which the torque ripple generated by the motor becomes large and the motor speed becomes unstable without being stabilized is prevented.

  Furthermore, when the electrical angular velocity is equal to or higher than the predetermined electrical angular velocity, the motor is controlled with the voltage command value set to zero.Therefore, as the electrical angular velocity of the rotor increases, the rotational angle detection capability of the rotational angle sensor is limited and the calculation cycle becomes rough. The controllability of the motor is deteriorated, and there is no problem that the torque ripple of the motor becomes large, and a stable load can be generated in the actuator.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a conceptual diagram of an actuator forming a part of a drive system in an embodiment. FIG. 2 is a system diagram of an actuator control apparatus. FIG. 3 is a diagram illustrating the PWM circuit. FIG. 4 is a block diagram showing the internal configuration of the actuator. FIG. 5 is a diagram showing the relationship between the voltage limit circle and the d-phase and q-phase voltage command values. FIG. 6 is a flowchart showing an example of a processing procedure for setting the voltage command value to zero. FIG. 7 is a map of gains to be multiplied by the voltage command value using the electrical angular velocity as a parameter.

  As shown in FIG. 1, the actuator in one embodiment includes a screw shaft 1 that is a rotating member and a ball screw nut 2 that is a linear member, and the linear motion of the ball screw nut 2 is changed to the rotational motion of the screw shaft 2. A motion conversion mechanism H for conversion and a motor M having a rotor R connected to the screw shaft 1 are provided.

  Specifically, the screw shaft 1 is rotatably engaged with the ball screw nut 2, and the upper end of the screw shaft 1 in FIG. 1 is connected to the rotor R of the motor M. Therefore, when the screw shaft 1 and the ball screw nut 2 exhibit a linear relative motion in the axial direction, the screw shaft 1 as a rotating member exhibits a rotational motion, and the rotational motion of the screw shaft 1 is the rotor R of the motor M. In this embodiment, the motion conversion mechanism H is a feed screw mechanism. Here, the rotational speed of the screw shaft 1 may be reduced through a reduction gear constituted by a gear mechanism or the like to transmit the rotational motion of the screw shaft 1 to the rotor R.

  Although not shown, the ball screw nut 2 is connected to a driven member. In this case, the driven member is linearly moved by driving the motor M. Therefore, in the present embodiment, the transmission member that transmits the power of the motor M to the driven member (not shown) is the motion conversion mechanism H, and this actuator and the driven member (not shown) constitute a drive system. .

  When the screw shaft 1 and the ball screw nut 2 exhibit a linear relative motion in the axial direction, the ball screw nut 2 is used when the screw shaft 1 cannot be rotated and the ball screw nut 2 is rotated instead. The rotational motion of 2 may be transmitted to the rotor R of the motor M. Further, the motion conversion mechanism H that is a transmission member may be a mechanism such as a rack and pinion other than those described above.

  In this case, the motor M includes a cylindrical frame 10, a stator S that is an armature provided on the inner peripheral side of the frame 10, and a rotor R that is rotatably supported by the frame 10. Specifically, the stator S includes a ring-shaped stator core 11 having a plurality of teeth, and windings 12 in U, V, and W phases wound around the teeth. The other rotor R includes a shaft 13 connected to one end of the screw shaft 1 and a driving magnet 14 attached to the outer periphery of the intermediate portion of the shaft 13.

  The drive magnet 14 is formed into a block so that a predetermined number of poles can be realized and bonded to the outer periphery of the shaft 13 or formed in an annular shape and divided and magnetized so as to have an outer periphery of the shaft 13. To be fitted.

  The motor M is equipped with a rotation angle sensor 15 for detecting the rotation angle (electrical angle) θ of the rotor R. Specifically, for example, the rotation angle sensor 15 is provided on the shaft 13. The resolver core and the resolver stator provided on the frame 10 are opposed to the resolver core, and the electrical angular velocity ω can be obtained from the electrical angle θ. In addition, as long as a calculation unit for calculating the electrical angular velocity ω from the electrical angle θ is separately provided, as the rotation angle sensor 15, an optical encoder may be employed, or the rotor R may have a sensing magnet. In the case of providing a magnetic sensor, a magnetic sensor such as a Hall element or an MR element may be provided on the frame 10.

  As described above, in this actuator, since the drive source is the motor M, when the motor M is driven by applying electric energy, the screw shaft 1 is rotated to drive the screw shaft 1 and the ball screw nut. 2 can be positively moved relative to each other, that is, can be stroked, can function as an actuator, and a driven member connected to a ball screw nut 2 (not shown) can be reciprocated.

  In addition, when the driven member is forcibly moved by an external force, the motor M is forced to receive rotational movement from the screw shaft 1 and a current flows through the winding 12 by induced electromotive force or power from the power source. Thus, a magnetic field is generated and an electromagnetic force is generated to generate a torque that suppresses the rotational motion of the screw shaft 1, so that it functions to suppress the relative linear motion of the screw shaft 1 and the ball screw nut 2. That is, in this case, the torque generated by the electric power obtained by the motor M regenerating kinetic energy input from the outside and converting it into electric energy, or by the electric power supplied from the power source in addition to this regeneration. Thus, the relative linear motion of the screw shaft 1 and the ball screw nut 2 can be suppressed.

  Therefore, in this drive system, since the motor M can function as both an actuator and a generator, the relative linear motion of the screw shaft 1 and the ball screw nut 2 can be suppressed.

  In order to control the current flowing through the winding 12 of the motor M, specifically, the U, V and W phase windings 12 are connected to the control device 20, and the motor M is connected to the control device 20. Is driven and controlled.

  As shown in FIG. 2, the control device 20 basically has each current target based on the electrical angular velocity ω and a torque command input from a host control device (not shown) that controls the driven member outside the drawing. Current target value calculation unit 26 for calculating values id * and iq *, and two-phase for calculating the d-phase current value and the q-phase current value by dq-converting the current flowing in two phases of the three phases of the winding 12 Proportional integration for calculating a d-phase voltage command value Vd and a q-phase voltage command value Vq based on each current target value id *, iq * and the d-phase and q-phase current values id, iq A control unit 22; a three-phase conversion calculation unit 23 that converts the d-phase voltage command value Vd and the q-phase voltage command value Vq into voltage command values Vu, Vv, and Vw of U, V, and W phases; Current detector for detecting a current value flowing in two phases iu and iv of U, V and W 24 and a PWM circuit 25 as a motor drive circuit.

  The control device 20 includes the d-phase and q-phase current target values id * and iq * determined by the current target value calculation unit 26, the d-phase obtained as a calculation result of the two-phase current calculation unit 21, and The motor M is proportionally integrated based on the deviations εd and εq from the q-phase current values id and iq, respectively. Note that proportional differential integration control may be performed by adding an element obtained by differentiating the deviation.

  Here, the current target value calculation unit 26 performs predetermined control on the d-phase and q-phase current target values id * and iq * based on the torque command output from the host vehicle control device and the electrical angular velocity ω of the rotor R. In this case, the output to the current / integral control unit 22 is not the torque command but the state of the force command to be generated by the actuator. And the current target value calculation unit 26 may perform the conversion. Further, a signal required for controlling the driven member, for example, acceleration, speed, and displacement is taken in by the current target value calculation unit 26 of the control device 20, and the current target value calculation unit 26 performs the same calculation as that of the host control device. Of course, it may be performed.

  Note that the actuator expansion / contraction amount, stroke speed, expansion / contraction acceleration, and the like necessary for controlling the driven member in the host control device are based on the electrical angle θ obtained from the rotation angle sensor 15, the pitch of the screw shaft 1, and the reduction ratio. There is no need to provide a separate sensor.

  The current target value calculation unit 26 basically calculates the q-phase current target value with the d-phase current target value set to 0, but when the electrical angular velocity ω of the rotor is large, d Of course, the field current control may be performed by inducing the phase current target value to a negative value.

  The current detector 24 is a non-contact type using a Hall element, a winding, or the like, or a current detection that obtains a current value from a voltage drop of a resistor connected in series with any two of the three-phase windings 12. A vessel may be used.

  The current detector 24 only needs to detect the current value flowing in two phases of the U, V, and W phases. This is described below from the electrical angle θ of the rotor R if the current values of the two phases are known. This is because it can be converted into d-phase and q-phase current values using Equation (3).

  Further, as shown in FIG. 3, the PWM circuit 25 includes a power supply E, six switching elements 41 that supply current to the windings 12 of the three phases of the motor M, and PWM pulse signals to the switching elements 41. The PWM circuit 25 includes a pulse generator (not shown) such as a multivibrator to be provided, and the PWM circuit 25 is configured to adjust the phase to each phase with a predetermined PWM duty ratio based on each voltage command value output from the proportional integration control unit 21. Supply current. The power supply E may be a battery mounted on the vehicle.

比例積分制御部２２は、各電流目標値ｉｄ*，ｉｑ*とｄ相およびｑ相における電流値ｉｄ，ｉｑの各偏差εｄ，εｑを算出し、算出された偏差εｄ，εｑを積分して得られた積分値に所定の積分ゲインを乗じ、さらには、各偏差εｄ，εｑに所定の比例ゲインを乗算し、積分ゲイン乗算後の値と比例ゲイン乗算後の値を加算して、各電圧指令値Ｖｄ，Ｖｑを出力する。 Then, using the electrical angle θ, the two-phase current calculation unit 21 converts the current values iv and iu into d-phase and q-phase current values id and iq as shown in the following equation (3). The converted d-phase and q-phase current values id and iq are output to the proportional-plus-integral control unit 22.

The proportional-plus-integral control unit 22 calculates each current target value id *, iq * and each deviation εd, εq of the current value id, iq in the d-phase and q-phase, and integrates the calculated deviation εd, εq. The obtained integral value is multiplied by a predetermined integral gain, and each deviation εd, εq is multiplied by a predetermined proportional gain. The values Vd and Vq are output.

また、このモータ制御装置は、リミッタ２７を備えており、このリミッタ２７は、三相変換演算部２３が出力する上記各電圧指令値Ｖｕ，Ｖｖ，Ｖｗのうち、ＰＷＭ開度が全開、すなわち、ＰＷＭデューティ比が最大値以上となる場合に、ＰＷＭデューティ比を最大値とする値に電圧指令値Ｖｕ，Ｖｖ，Ｖｗを制限する。 Further, the d-phase voltage command value Vd and the q-phase voltage command value Vq are input to the three-phase conversion calculation unit 23 that converts the voltage command values of the U, V, and W phases as described above. The phase conversion calculation unit 23 converts the d-phase voltage command value Vd and the q-phase voltage command value Vq to the actual voltage command values Vu, Vv, and Vw of the U, V, and W phases by the calculation of the following equation (4). The converted voltage command values Vu, Vv, Vw are output to the PWM circuit 25.

Further, the motor control device includes a limiter 27, and the limiter 27 has the PWM opening fully opened among the voltage command values Vu, Vv, and Vw output from the three-phase conversion calculation unit 23, that is, When the PWM duty ratio is equal to or greater than the maximum value, the voltage command values Vu, Vv, and Vw are limited to values that maximize the PWM duty ratio.

Furthermore, a limiter 28 and a limiter 29 are provided. The limiter 28 limits the upper limit of each current target value id * and iq * calculated by the current target value calculation unit 26, and the limiter 29 includes the proportional integration control unit 22. The upper limits of the calculated d-phase voltage command value Vd and q-phase voltage command value Vq are limited. Incidentally, the limiter 28 is prevented voltage command value Vd of the d-phase and q phase, which will be described later, Vq deviation εd in the proportional integral control unit 22 at conditions to saturate, the integrated saturation and prevent the εq increases advance The limiter 29 prevents the d-phase and q-phase voltage command values Vd and Vq from becoming unrealizable values.

  Here, when the internal configuration of the actuator described above is shown in a block diagram, as shown in FIG. 4, the portion surrounded by a broken line indicates the internal configuration of the motor M, and the voltage in the d phase and q phase is The motor M outputs torque. On the other hand, a portion surrounded by a one-dotted line indicates a mechanical portion in which the rotational motion of the rotor R is converted into the stroke of the actuator, that is, the configuration of the rotor R and the motion conversion mechanism H, and the torque output by the motor M The actuator will stroke in response to this input.

  In FIG. 4, 1 / s is an integral symbol described by a Laplace operator, and Cμ is a rotor generated by friction between the ball screw nut 2 and the screw shaft 1 or friction of the rotor R portion of the motor M. R is a damping coefficient for calculating the force that suppresses the rotation of R from the mechanical angular velocity of the motor M, PP is the pole pair number of the motor M for calculating the electrical angular velocity ω of the motor M from the mechanical angular velocity, and Kt is , Q is a torque constant for calculating the generated torque of the motor M from the q-axis current, I is the moment of inertia of the rotor R, K is the torsion spring constant of the entire member connected to the rotor R, L Is the inductance of each of the d-phase and q-phase windings, and R is the resistance of each of the d-phase and q-phase windings.

  As can be understood from FIG. 4, the voltages applied to the d phase and the q phase interfere with the other phase by the respective inductances L, and the q phase is induced by the electrical angular velocity ω of the rotor R. It is affected by electric power.

  Further, in the present embodiment, the rotor R resonates at the resonance frequency fm represented by the expression (1) because the screw shaft 1 functions as a spring element against torsion in the circumferential direction.

  The resonance of the mechanical part in the drive system affects the interference path of each phase of dq via the pole pair number pp, and also affects the q phase as an induced electromotive force. Then, in the electric circuit of the dq coordinate, a waveform having the same frequency as the resonance of the mechanical part is generated, and at this time, the phase of the q-phase current iq is in phase with the torque generated by the torsion spring element of the mechanical part. When the vibration is excited and the braking force of the motor M is reduced to cause an unstable vibration mode, the phase of the q-phase current iq is opposite to the torque generated by the torsion spring element of the mechanical part. Vibration will be attenuated.

  Next, a circle having a radius of a saturation voltage corresponding to the voltage of the power supply E in the dq coordinates (the voltage limit circle) in which the combined vector length of the d-phase and q-phase voltage command values Vd and Vq shown in FIG. The combined vector of the d-phase and q-phase voltage command values Vd and Vq is limited by the voltage limit circle, and the d-phase and q-phase voltage command values Vd and Vq are substantially constant on the voltage limit circle. The voltage command value is offset from the value.

  And if the internal structure of the actuator shown in FIG. 4 is a linear system, even if the d-phase and q-phase voltage command values Vd and Vq are offset, only the input to the system is changed and stability is improved. Although there is no change, the internal configuration of the actuator is a non-linear system in which the interference path of each phase of dq is multiplied by sine waves. Therefore, when the voltage command values Vd and Vq of d phase and q phase are offset, Correspondingly, a component having the same frequency as the resonance frequency fm of the mechanical portion appears large in the interference component of each phase of dq, or a frequency component twice as large as the resonance frequency fm of the mechanical portion appears. Specifically, when sine waves are multiplied with each other, a frequency component that is twice the frequency of the sine wave always appears even if the phase is shifted, and when an offset is added, a signal having a basic component is generated.

  For this reason, the amplification factor of the component having the same frequency as the resonance frequency fm of the mechanical portion appearing in the interference component of each dq phase changes according to the angle of the combined vector of the voltage command values Vd and Vq of each phase of dq with respect to the q axis. However, when the electrical resonance frequency fe of the motor M and the resonance frequency fm in the circumferential vibration of the rotor R approach each other, a vibration mode that excites each other and causes oscillation may appear.

  The electrical resonance frequency fe of the motor M, which is the resonance frequency at which the current flowing in the winding 12 resonates, is an actuator proportional to the electrical angular velocity ω because of the structure of the actuator, as shown in the above equation (2). Depending on the stroke speed of the actuator, that is, the expansion / contraction speed of the actuator. That is, as the stroke speed increases, the electrical resonance frequency fe of the motor M also increases. Therefore, the electrical resonance frequency fe of the motor M and the resonance frequency fm in the circumferential vibration of the rotor R. It will be easy to understand that the

  Further, as described above, the vibration mode appears when the motor M is controlled in accordance with the d-phase and q-phase voltage command values Vd and Vq in a state where the d-phase and q-phase voltage command values Vd and Vq are saturated. Is done. On the other hand, in the passive state, even if the mechanical part resonates, it is attenuated by friction and the like, so it is a vibrational but stable system, and the vibration mode depending on the interference of each phase of dq is also connected to the mechanical part. Since it is stable if there is no success, it remains stable even if they are connected.

In other words, a state where the rotor R of the motor M is forcibly rotated and only induced electromotive force is generated in the U, V, W phase windings 12 (passive state), that is, U, V, W When the change in the voltage between the terminals of each phase winding 12 is caused only by the induced electromotive force, the vibration mode does not appear.

  Therefore, in the present embodiment, the electrical angular velocity ω of the rotor R is greater than or equal to a predetermined electrical angular velocity α between the proportional-plus-integral control unit 22 and the three-phase conversion calculation unit 23 in order to prevent the vibration mode from appearing. In this case, a gain multiplication unit 30 for multiplying the d-phase and q-phase voltage command values Vd and Vq by a gain of zero is provided. The gain multiplication unit 30 monitors the electrical angular velocity ω output from the rotation angle sensor 15, and when the electrical angular velocity ω becomes equal to or higher than a predetermined electrical angular velocity α, the gain is set to zero and the d-phase and q-phase values are set. The voltage command values Vd and Vq are multiplied by a zero gain, and the gain-multiplied d-phase and q-phase voltage command values Vd and Vq are output to the three-phase conversion calculation unit 23.

When the electrical angular velocity ω is equal to or higher than the predetermined electrical angular velocity α, the three-phase conversion calculation unit 23 calculates the voltage command values Vu, Vv, Vw from the d-phase and q-phase voltage command values Vd, Vq that take zero values. As a result, the PWM circuit 25 drives the switching element 41 by setting the PWM duty indicating the ratio of the ON duty to the entire ON duty and OFF duty to 50%. Only a current caused by an induced electromotive force generated when R is forcibly rotated by an external force flows. Specifically, when the PWM duty is 50%, it means that the upper side or the lower side in FIG. 3 of the switching element 41 is in the ON state. Since the windings 12 of each phase are conducted on the upper or lower line, the windings 12 of each phase of the motor M can be short-circuited and maintained in a passive state. Also, in fact, when the PWM drive is dead time, this time, the characteristic of the step-up chopper, overcame voltage of the power source E, so that around the current through the power E.

  The PWM duty of 50% includes the case where the ratio of the on time to the time excluding the dead time per cycle is 50%.

  In this case, the predetermined electrical angular velocity α is a region of the electrical angular velocity ω that excites the circumferential vibration of the rotor R in a state in which the voltage command values Vd and Vq are saturated, that is, an electrical voltage that causes a vibration mode. The electrical angular velocity is smaller than the angular velocity ω. Specifically, the electrical resonance frequency fe of the motor M at the electrical angular velocity α is set to be lower than at least the resonance frequency fm in the circumferential vibration of the rotor R.

  By doing so, before the electrical resonance frequency fe of the motor M approaches the resonance frequency fm in the circumferential vibration of the rotor R due to the increase in the electrical angular velocity ω of the rotor R, a vibration mode is developed. The d-phase and q-phase voltage command values Vd and Vq are set to zero to prevent the vibration mode from appearing.

  In the present embodiment, the gain multiplication unit 30 is configured to set the d-phase and q-phase voltage command values Vd and Vq to zero, but U and V calculated by the three-phase conversion calculation unit 23 are used. , W may be provided behind the three-phase conversion operation unit 23 so that the voltage command values Vu, Vv, Vw of each phase are zero.

  Therefore, when the stroke speed at the time of expansion and contraction of the actuator is such that the electrical angular speed ω of the rotor R is less than the predetermined electrical angular speed α, the electrical resonance frequency fe of the motor M is the circumferential direction of the rotor R. The resonance frequency fm is smaller than the resonance frequency fm in vibration, and in such a state, the vibration mode is maintained even if normal control (control based on the current target values id * and iq * calculated by the current target value calculation unit 26) is performed. On the other hand, even if the stroke speed at the time of expansion / contraction of the actuator reaches a stroke speed at which the electrical angular speed ω of the rotor R is equal to or higher than the predetermined electrical angular speed α, the ripple of torque generated by the motor M is generated. The occurrence of a vibration mode that becomes large and vibrates without stabilizing the stroke speed of the actuator is prevented.

  Further, when the electrical angular velocity ω of the rotor R increases, the limit of the rotation angle detection capability and the calculation cycle of the rotation angle sensor 15 become rough, so that the controllability of the motor M inevitably deteriorates and the torque ripple of the motor M increases. However, as described above, when the electrical angular velocity ω is equal to or higher than the predetermined electrical angular velocity α, the voltage command values Vd, Vq (Vu, Vu, Vw) are set to zero and the motor M is operated. Since the control is performed, the above-described problems do not occur and a stable load can be generated in the actuator.

  When the actuator is used as a suspension, that is, when the driven member in the drive system is an unsprung member, and the motor M in the actuator is connected to the sprung member, or the driven member in the drive system is the sprung member. When the motor M in the actuator is connected to the unsprung member, when the vibration mode is developed, the vibration in the vibration mode is also transmitted to the sprung member. It is possible to prevent unpleasant vibrations from being transmitted to the sprung member.

  As described above, the vibration mode appears when the electrical resonance frequency fe of the motor M, which increases as the electrical angular velocity ω of the rotor R increases, is close to the resonance frequency fm in the circumferential vibration of the rotor R. Therefore, the predetermined electrical angular velocity α can be determined according to the resonance frequency fm in the circumferential vibration of the rotor R.

  In this case, the resonance frequency fm in the circumferential vibration of the rotor R is the screw that is connected between the rotor R and the driven member (not shown) connected to the rotor R and the inertia moment I of the rotor R of the motor M. The total torsion spring constant K of the shaft 1 can be obtained using the formula (1). In addition, when the structure different from the said motion conversion mechanism H is employ | adopted for the transmission member of a drive system, the torsion spring constant (circumferential torsional rigidity) of the whole transmission member will be calculated backward.

  Further, when the inertia moment of the rotating member in the motion conversion mechanism H is so large that it cannot be ignored with respect to the value of the rotating moment of the rotor R, the mechanical resonance frequency fm of the actuator may be obtained more strictly. That is, in addition to the inertia moment of the rotor R of the motor M, the inertia moment of the rotating member of the motion conversion mechanism H may be added to the value of the inertia moment I.

  On the other hand, the resonance frequency fm in the circumferential vibration of the rotor R may be set so as to satisfy the relationship fe <fm with respect to the electrical resonance frequency fe of the motor M at a predetermined electrical angular velocity α. The upper limit of the predetermined electrical angular velocity α can be uniquely determined from the resonance frequency fm, the resistance R of the winding 12 of the motor M, and the inductance L.

  The relationship between the stroke speed of the actuator and the rotational speed of the rotor R of the motor M is such that the screw shaft 1 with respect to the linear relative displacement between the ball screw nut 2 that is the linear motion member of the motion conversion mechanism H and the screw shaft 1 that is the rotating member. Is set by the relative rotational speed with respect to the ball screw nut 2. The relationship between the rotational speed of the rotor R and the electrical angular speed ω of the rotor R is determined by the number of pole pairs.

  Therefore, the stroke speed of the actuator when the motor M is rotating at the predetermined electrical angular speed α can be obtained.

  As described above, the upper limit of the predetermined electrical angular velocity α can be obtained. However, in this embodiment, the resonance frequency fm in the circumferential vibration of the rotor R is screwed with the ball screw nut 2 on the screw shaft 1. The position to be changed changes according to the displacement of the stroke of the actuator.

  The torsion spring constant of the screw shaft 1 is such that the distance between the ball screw nut 2 and the rotor R becomes long when the ball screw nut 2 is screwed at the lowest end of the screw shaft 1 in FIG. In this state, the smallest value is taken.

  That is, when the actuator reaches the maximum extension state, the torsion spring constant of the screw shaft 1 becomes small. Therefore, the actuator is interposed between the rotor R and the sprung member or the unsprung member in this state. If the resonance frequency fm in the circumferential vibration of the rotor R is set on the basis of the torsion spring constant of the entire member, and the upper limit of the predetermined electrical angular velocity α is determined on the basis of this resonance frequency fm, the stroke of the actuator Thus, the occurrence of the vibration mode can be prevented.

  The same applies to the case where the ball screw nut 2 is a rotating member. When the actuator is in its maximum extension state, the torsion spring constant of the screw shaft 1 is the smallest, so that the rotor is the same as described above. The resonance frequency fm in the circumferential vibration of R may be set.

  Here, the predetermined electrical angular velocity α is proportional to the stroke speed of the actuator, and the upper limit is determined by the value of the resonance frequency fm in the circumferential vibration of the rotor R. Is larger, the normal control region for the stroke speed, that is, the control based on the current target values id * and iq * calculated by the current target value calculation unit 26 is performed, and the gain multiplication unit 30 is applied to the stroke speed. As a result, the q-phase voltage command value Vq as a torque command to be output to the motor M is not forced to be zero and the controllable region becomes large.

  The output torque of the motor M during normal control is such that the rotor M of the motor M is forcibly rotated and only the induced electromotive force is generated in the U, V, W phase windings 12. Since the torque is larger than the output torque, a large load can be output as the entire actuator during normal control.

  From the viewpoint of the load generated by the actuator, it is desirable to set the predetermined electrical angular velocity α as large as possible. However, setting the predetermined electrical angular velocity α to be large requires setting the resonance frequency fm in the circumferential vibration of the rotor R to be large.

  In order to increase the resonance frequency fm in the circumferential vibration of the rotor R described above, the entire member interposed between the rotor R and the sprung member or the unsprung member, in this case, the rotor R Thus, the torsion spring constant (circumferential torsional rigidity) K of the screw shaft 1 that functions as a circumferential spring element must be set large.

  The actuator is provided with many rotating members such as the rotor R and the screw shaft 1, and its inertial mass is large and the moment of inertia is increased with respect to the input of high-frequency vibration. There is a characteristic that it becomes easy to transmit the vibration on the member side to the sprung member, and if the entire torsion spring constant of the member interposed between the rotor R and the sprung member or the unsprung member is set too large, The characteristic of easily transmitting the vibrations obstructs the riding comfort in the vehicle.

  The above-mentioned predetermined stroke speed is used when, for example, an actuator is interposed between a sprung member and an unsprung member of a vehicle and used as a suspension for controlling the posture of the sprung member and suppressing vibration by the actuator. If the stroke speed of the actuator at a predetermined electrical angular velocity α is specifically set to 1 m / s, the vibration mode is manifested in the stroke speed region where the ride comfort of the vehicle should be emphasized. And the entire member interposed between the rotor R and the sprung or unsprung member, in this case, the entire screw shaft 1 that functions as a spring element in the circumferential direction with respect to the rotor R. It is possible to avoid a situation in which the torsion spring constant (circumferential torsional rigidity) must be set larger than necessary.

  Further, when the actuator is used as a suspension as described above, if the overall torsion spring constant of the member interposed between the rotor R and the sprung member or the unsprung member is set too large, the vibration is transmitted. However, as described above, it functions as a spring element by setting the stroke speed at which the predetermined electrical angular speed α is set to about 1 m / s, as described above. Since it is possible to avoid a situation where the torsion spring constant of the entire member interposed between the rotor R and the sprung member or the unsprung member must be set larger than necessary, it is possible to improve riding comfort and vibration in the vehicle. It is possible to highly satisfy both of the prevention of mode expression.

  When the linear motion member of the motion conversion mechanism H is the screw shaft 1 and the rotating member is the ball screw nut 2, the screw shaft 1 may be directly connected to the sprung member or the unsprung member. Therefore, it is mainly the screw shaft 1 that is interposed between the rotor R and the sprung or unsprung member and functions as a spring element.

  Next, the specific configuration of the control device 20 will be described. The components other than the PWM circuit 25 of the control device 20 described above are specifically configured as hardware components such as a current detector 24 and a rotation angle sensor 15. An amplifier for amplifying each output signal, a converter for converting an analog signal into a digital signal, a storage device such as a CPU (Central Processing Unit) and a ROM (Read Only Memory), a RAM (Random Access Memory), a crystal A known computer system (not shown) having an oscillator and a bus line for connecting them may be used, and voltage command values Vu, Vv, Vw can be output to the PWM circuit 25. That's fine. In addition, each part other than the PWM circuit 25 of the control apparatus 20 as this hardware may be integrated with the controller of the apparatus in which this drive system is mounted.

  In this case, the processing procedure for performing normal control for calculating the current target values id * and iq * in the d phase and the q phase in the current target value calculation unit 26 and the above-described predetermined electrical angular velocity α or more. The processing procedure for setting the d-phase and q-phase voltage command values Vd and Vq to zero is stored in advance in a ROM or other storage device as a program.

  Hereinafter, the processing procedure for setting the d-phase and q-phase voltage command values Vd and Vq to zero when the control device 20 is equal to or higher than the predetermined electrical angular velocity α will be described in detail with reference to the flowchart shown in FIG. Explained.

  In step F1, the control device 20 reads the electrical angular velocity ω of the rotor R, and determines whether or not the electrical angular velocity ω is equal to or higher than a predetermined electrical angular velocity α.

  Then, when the electrical angular velocity ω is less than the predetermined electrical angular velocity α, the present processing procedure is terminated. On the other hand, when the electrical angular velocity ω is equal to or higher than the predetermined electrical angular velocity α, the process proceeds to Step F2.

  Subsequently, in step F2, the d-phase and q-phase voltage command values Vd and Vq should be multiplied from the map of gains to be multiplied with the d-phase and q-phase voltage command values Vd and Vq using the electrical angular velocity ω as a parameter. Set the gain. This gain setting is performed by the gain multiplier 30 described above.

  In the map, specifically, as shown in FIG. 7, the gain changes from 1 to zero with the electrical angular velocity ω as a parameter, and the electrical angular velocity ω of the rotor R is a predetermined electrical speed. When the angular velocity α is set, the gain is set to zero. However, when the electrical angular velocity ω of the rotor is equal to or higher than a certain electrical angular velocity β smaller than the predetermined electrical angular velocity α, the increase in the electrical angular velocity ω is increased. The gain decreases.

  Specifically, the gain takes a value of 1 until the electrical angular velocity ω reaches a certain electrical angular velocity β, and decreases from the electrical angular velocity β to a predetermined electrical angular velocity α as the electrical angular velocity ω increases. It becomes zero when the electrical angular velocity ω reaches a predetermined electrical angular velocity α.

  When a gain is selected from the electrical angular velocity ω and the map, the process proceeds to step F3, where the selected gain is multiplied by the d-phase and q-phase voltage command values Vd and Vq, respectively, and the final d The phase and q-phase voltage command values Vd and Vq are calculated.

  Therefore, according to this control device 20, when the electrical angular velocity ω of the rotor R is equal to or higher than the electrical angular velocity β and less than the predetermined electrical angular velocity α, the gain decreases as the electrical angular velocity ω increases and should be normally output. The d-phase and q-phase voltage command values Vd and Vq decrease, and the normal control (control based on the current target values id * and iq * calculated by the current target value calculation unit 26) gradually fades out. become. The electrical angular velocity β may be a value smaller than the electrical angular velocity α, but the degree of fluctuation of the d-phase and q-phase voltage command values Vd and Vq with respect to the electrical angular velocity ω is so great that the effect of the fade-out is not lost. It is better to set a certain difference from the electrical angular velocity α.

  Further, when the electrical angular velocity ω of the rotor R increases and becomes equal to or higher than the predetermined electrical angular velocity α, the gain becomes zero, and the electrical resonance frequency fe of the motor M approaches the resonance frequency fm in the circumferential vibration of the rotor R. Before the vibration mode is manifested, the motor M is controlled so that the change in the voltage between the terminals of the U, V and W phase windings 12 is caused only by the induced electromotive force.

  As described above, in the control device 20 according to the present embodiment, the normal control is suddenly stopped, and the change in the voltage between the terminals of the U, V, W phase windings 12 of the motor M is only the induced electromotive force. Since the normal control is faded out without causing the control to be caused by the state caused by the motor, the fluctuation of the torque generated by the motor M when the normal control is aborted does not increase, and the generated load of the actuator It is possible to prevent large fluctuations from occurring.

  That is, in the present control device 20, even when the normal control is terminated, the actuator generated load does not fluctuate greatly, so that the stroke speed does not change rapidly and the actuator is used as a suspension. In such a case, the ride comfort in the vehicle can be further improved without causing the vehicle occupant to feel uncomfortable or uncomfortable.

  The driven member may be any member that is driven by the motor M, and may be, for example, a wheel in an electric vehicle or a wheel in electric power steering. When the driven member is a wheel in an electric vehicle, the transmission member may be a shaft connecting the rotor R of the motor M and the wheel. When the drive system is an electric power steering, the transmission member is a rack and pinion. Alternatively, a ball screw nut connected to the rotor R and a screw shaft connected to the wheel side may be used.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a key map of an actuator in one embodiment. It is a system diagram of an actuator control device. It is a figure which shows a PWM circuit. It is a block diagram which shows the internal structure of an actuator. It is a figure which shows the relationship between a voltage limiting circle and the voltage command value of d phase and q phase. It is the flowchart which showed an example of the process sequence for setting a voltage command value to zero. It is a map of the gain which should be multiplied to the voltage command value which made electrical angular velocity a parameter. It is the figure which showed the generated load (damping force) with respect to the stroke speed in the conventional actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw shaft which is a rotating member 2 Ball screw nut which is a linear member 10 Frame 11 Stator core 12 Winding 13 Shaft 14 Driving magnet 15 Rotation angle sensor 20 Controller 21 Two-phase current calculation unit 22 Proportional integration control unit 23 Three-phase conversion calculation Unit 24 current detector 25 PWM circuit 26 target current value calculation unit 27, 28, 29 limiter 30 gain multiplication unit E power source H motion conversion mechanism M motor R rotor S stator

Claims (11)

In a control device for controlling a motor in a drive system that transmits the power of the motor to the driven member via a transmission member interposed between the driven member driven by the motor and the rotor of the motor, a predetermined electrical angular velocity and the voltage command value is smaller electrical angular velocity than the area of the electrical angular speed exciting the circumferential direction vibration of the rotor to act as a moment of inertia in a state of saturation, when the electrical angular velocity of the rotor is equal to or larger than the predetermined electric angular speed, voltage command value A control device for controlling a motor with zero as a reference. The d-phase and q-phase current values are obtained from the current flowing through the motor and the electrical angle of the rotor using dq conversion, and the motor is controlled based on the d-phase voltage command value and the q-phase voltage command value. If the angular velocity is equal to or larger than the predetermined electric angular velocity control apparatus according to claim 1, characterized in that to control the motor voltage command value of the d-phase and q-phase zero. Claims the electrical angular velocity of the rotor and controls the motor by decreasing the voltage command value by multiplying a gain which decreases with increasing electrical angular velocity becomes to the predetermined electrical angular velocities smaller one electrical angular velocity than 3. The control device according to 1 or 2. The motor is PWM control, the control device according to any one of the voltage command value becomes zero claim 1, characterized in that to control the motor a PWM duty ratio of 50% 3. Said predetermined electrical angular velocity, any one of claims 1 to 4, characterized in that electrical resonance frequency of the motor at the electrical angular velocity is set to be smaller than the resonance frequency in the circumferential direction vibration of at least the rotor The control device according to item . In a control device for an actuator comprising a motion conversion mechanism that has a linear motion member and a rotary member, and converts a linear motion of the linear motion member into a rotational motion of the rotary member, and a motor having a rotor coupled to the rotary member. a predetermined electrical angular velocity voltage command value is smaller electrical angular velocity than the area of the electrical angular speed exciting the circumferential direction vibration of the rotor to act as a moment of inertia in a state of saturation, when the electrical angular velocity of the rotor is equal to or larger than the predetermined electric angular velocity An actuator control device that controls a motor by setting a voltage command value to zero. The d-phase and q-phase current values are obtained from the current flowing through the motor and the electrical angle of the rotor using dq conversion, and the motor is controlled based on the d-phase voltage command value and the q-phase voltage command value. If the angular velocity is equal to or larger than the predetermined electric angular velocity control apparatus of an actuator according to claim 6, characterized in that to control the motor voltage command value of the d-phase and q-phase zero. Billing electrical angular velocity of the rotor shall be the control means controls the motor by decreasing the voltage command value by multiplying a gain which decreases with increasing electrical angular velocity becomes to the predetermined electrical angular velocities smaller one electrical angular velocity than Item 8. The actuator control device according to Item 6 or 7 . The motor is PWM control, the control device of the actuator according to an item to one of the voltage command value becomes zero claim 6, characterized in that to control the motor a PWM duty ratio of 50% 8. Said predetermined electrical angular velocity, any one of claims 6 to 9, characterized in that electrical resonance frequency of the motor at the electrical angular velocity is set to be smaller than the resonance frequency in the circumferential direction vibration of at least the rotor The actuator control device according to Item . The actuator according to claims 6 to stroke speed unless become 1 m / s or more electrical angular velocity of the rotor, characterized by comprising a set so as not to be more than the predetermined electrical angular velocities in any one of 10 Actuator control device.

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