Torque control device and drive system
阅读说明：本技术 转矩控制装置、驱动系统 (Torque control device and drive system ) 是由 百濑博文 于 2019-07-17 设计创作，主要内容包括：本发明提供转矩控制装置、驱动系统,良好地抑制打齿音,并提高簧上减振控制的工作频率。在本转矩控制装置中,基于向电动马达的要求转矩即马达要求转矩与簧上减振转矩乘以增益所得到的值相加而成的值来决定从电动马达输出的转矩的目标值即目标马达转矩,但是增益可变。例如,在马达要求转矩比簧上减振转矩小的情况下,无论有无加速要求,都可以将增益设为比1小且比0大的值。由此,即使在马达要求转矩比簧上减振转矩小而存在加速要求的情况下,也能够抑制打齿音并执行簧上减振控制。由此,能够提高簧上减振控制的频率。(The invention provides a torque control device and a drive system, which can well inhibit tooth beating sound and improve the working frequency of sprung vibration damping control. In the torque control device, the target motor torque, which is the target value of the torque output from the electric motor, is determined based on the value obtained by adding the motor required torque, which is the required torque to the electric motor, and the sprung vibration damping torque multiplied by the gain. For example, when the motor required torque is smaller than the sprung vibration damping torque, the gain may be set to a value smaller than 1 and larger than 0 regardless of the presence or absence of the acceleration request. Thus, even when the motor required torque is smaller than the sprung vibration damping torque and there is a request for acceleration, the sprung vibration damping control can be executed while suppressing the rattling noise. This can increase the frequency of sprung vibration damping control.)
1. A drive system, comprising:
a drive device provided in a vehicle and including at least an electric motor; and
a torque control device that controls a torque output from the electric motor by controlling an operation of the electric motor, wherein,
the torque control device includes:
a target motor torque determination unit that determines a target motor torque that is a target value of torque output from the electric motor, based on a magnitude obtained by adding a motor required torque determined based on a vehicle required torque that is torque required to drive the vehicle and a sprung vibration damping torque that is torque for suppressing sprung vibration multiplied by a gain; and
and a gain determination unit configured to determine the gain to be a smaller value when the absolute value of the motor required torque is smaller than the sprung vibration damping torque, as compared to when the absolute value of the motor required torque is larger than the sprung vibration damping torque.
2. The drive system of claim 1,
the target motor torque determination unit includes:
a motor required torque determination unit that determines the motor required torque based on the vehicle required torque; and
a sprung vibration damping torque determination unit that determines the sprung vibration damping torque based on a displacement in the vertical direction on a spring of the vehicle,
the target motor torque determination unit determines the target motor torque based on a magnitude obtained by adding the gain to the sprung vibration damping torque determined by the sprung vibration damping torque determination unit, and the motor required torque determined by the motor required torque determination unit.
3. The drive system according to claim 1 or 2,
the gain determination unit sets the gain to 1 when a value obtained by subtracting a value on an envelope curve obtained for the sprung vibration damping torque from an absolute value of the motor required torque is equal to or greater than a set value,
when the value obtained by subtracting the value on the envelope acquired for the sprung vibration damping torque from the absolute value of the motor required torque is smaller than the set value, the gain determination unit determines the gain to be a value smaller than 1 based on a ratio that is a value obtained by dividing the absolute value of the motor required torque by the value on the envelope acquired for the sprung vibration damping torque.
4. The drive system of claim 3,
the gain determination unit includes a ratio acquisition unit that acquires, as the ratio, a value obtained by dividing an absolute value of the motor required torque by a value on an envelope acquired for the sprung vibration damping torque.
5. The drive system of claim 4,
when the value obtained by subtracting the value on the envelope acquired for the sprung vibration damping torque from the absolute value of the motor required torque is smaller than the set value, the gain determining unit determines the gain as a value obtained by subtracting the set value from the ratio acquired by the ratio acquiring unit and dividing the value by the value on the envelope acquired for the sprung vibration damping torque.
6. The drive system of claim 4,
the gain determining unit sets the gain to 1 when the ratio acquired by the ratio acquiring unit is equal to or greater than a set ratio,
when the ratio acquired by the ratio acquisition unit is smaller than the set ratio, the gain determination unit determines the gain to be a value smaller than 1 based on the ratio.
7. The drive system of any one of claims 3 to 6,
the gain determination unit includes an envelope acquisition unit that acquires an envelope regarding the sprung vibration damping torque.
8. The drive system according to any one of claims 1 to 7,
the drive means includes the electric motor and an engine,
the torque control device includes a motor required torque determination unit that determines the motor required torque based on a value obtained by subtracting an engine torque, which is a driving torque output from the engine, from the vehicle required torque.
9. A torque control device that controls a torque output from an electric motor by controlling an operation of the electric motor of a drive device of a vehicle including at least the electric motor, the torque control device comprising:
a target motor torque determination unit that determines a target motor torque that is a target value of torque output from the electric motor, based on a magnitude obtained by adding a motor required torque determined based on a vehicle required torque that is torque required to drive the vehicle and a sprung vibration damping torque that is torque for suppressing sprung vibration multiplied by a gain; and
and a gain determination unit configured to determine the gain to be a smaller value when the absolute value of the motor-requested torque is smaller than the amplitude of the sprung vibration damping torque, as compared to when the absolute value of the motor-requested torque is larger than the amplitude of the sprung vibration damping torque.
Technical Field
The present invention relates to a torque control device that controls torque by controlling a drive device of a vehicle, and a drive system including the torque control device.
Background
Therefore, in the torque control device described in
In the torque control device described in patent document 2, when the occurrence of the zero cross is predicted with respect to the output torque, for example, when stop control for stopping the driving of the engine is performed, sprung vibration damping control is prohibited. This can suppress tooth hitting noise caused by sprung vibration damping control.
[ Prior Art document ]
[ patent document ]
[ patent document 1 ] Japanese patent laid-open publication No. 2017-030667
[ patent document 2 ] Japanese patent application laid-open No. 2010-125986
Disclosure of Invention
The invention aims to suppress tooth hitting sound and improve the operating frequency of sprung vibration damping control.
The torque control device of the present invention controls the torque output from an electric motor by controlling the operation of the electric motor of a drive device of a vehicle having at least the electric motor. In the torque control device, the target motor torque, which is the target value of the torque output from the electric motor, is determined based on the value obtained by adding the motor required torque, which is the required torque to the electric motor, and the sprung vibration damping torque multiplied by the gain. For example, when the motor required torque is smaller than the sprung vibration damping torque (an example when zero crossing is predicted), the gain may be set to a value smaller than 1 and larger than 0 regardless of the presence or absence of the acceleration request. Thus, even when the motor required torque is smaller than the sprung vibration damping torque and there is a request for acceleration, the sprung vibration damping control can be executed while suppressing the rattling noise. As described above, the torque control device can increase the operating frequency of sprung vibration damping control as compared with the torque control devices described in
Drawings
Fig. 1 is a conceptual diagram showing a drive system including a torque control device according to
Fig. 2 is a diagram conceptually showing an operation of the torque control device.
Fig. 3 is a diagram showing a motor required torque of the second MG of the drive device of the drive system.
Fig. 4 is a diagram showing sprung vibration damping torque acquired by the torque control device.
Fig. 5A is a diagram showing an absolute value of the motor required torque of the second MG of the drive device. Fig. 5B is a diagram showing an envelope of the sprung vibration damping torque. Fig. 5C is a graph showing the gain.
Fig. 6 is a flowchart showing a target motor torque determination routine stored in the storage unit of the torque control device.
Fig. 7 is a diagram showing the target motor torque.
Fig. 8 is a flowchart showing another target motor torque determination routine stored in the storage unit of the torque control device.
Description of the reference numerals
6: drive device
8: torque control device
10: engine
12: second MG
14: inverter with a voltage regulator
16: power distribution mechanism
26: speed reducer
30: hybrid ECU
41: accelerator opening degree sensor
42: wheel speed sensor
43: pitch rate sensor
44: sprung acceleration sensor
Detailed Description
Hereinafter, a drive system including the torque control device according to the present embodiment will be described with reference to the drawings. In the present embodiment, a case where the torque control device of the present invention is mounted on a hybrid vehicle will be described.
[ example 1 ]
As shown in fig. 1, the drive system includes a drive device 6, a torque control device 8, and the like. The drive device 6 includes an engine 10, a first motor generator 11 (hereinafter referred to as a first MG11), a second motor generator 12 (hereinafter referred to as a second MG12), inverters 13, 14, a battery 15, a power distribution mechanism 16, and the like.
The engine 10 is a gasoline engine, but may be a diesel engine.
The first MG11 and the second MG12 are permanent magnet synchronous motors, and are connected to the inverters 13 and 14, respectively. When the first MG11 and the second MG12 are operated as motors, the electric power of the battery 15 is supplied to the first MG11 and the second MG12 by the control of the inverters 13 and 14, respectively, and in this case, the direct current is converted into a three-phase alternating current.
On the other hand, the first MG11 and the second MG12 generate electric power in a state where the rotary shaft is rotated by an external force. When the first MG11 and the second MG12 are operated as generators by the control of the inverters 13 and 14, the electric power output from the first MG11 and the second MG12 is charged into the battery 15, but in this case, the three-phase alternating current is converted into direct current. The regenerative braking torque is applied to the drive wheels W by charging (regeneration of electric power) the battery 15. Note that, in both the case where the second MG12 is operated as a motor and the case where the second MG12 is operated as a generator, the motor torque, which is the torque output from the second MG12, is controlled by the control of the inverter 14. The motor torque when the second MG12 is operated as a motor is represented by a positive value, and the motor torque when the second MG12 is operated as a generator is represented by a negative value.
The power distribution mechanism 16 distributes the driving torque of the engine 10 into the power for driving its own output shaft 18 and the power for driving the first MG11 as a generator. The power distribution mechanism 16 is constituted by a planetary gear mechanism. The planetary gear mechanism includes a sun gear 20, a pinion 21, a carrier 22, and a ring gear 23. The engine 10 is connected to the carrier 22, and power is transmitted to the sun gear 20 and the ring gear 23 via the pinion gears 21. The first MG11 is connected to the sun gear 20, and the first MG11 is operated by power transmitted from the sun gear 20. The output shaft 18 is connected to the ring gear 23, and the second MG12 is connected via the reduction gear 26. The output shaft 18 of the power distribution mechanism 16 is coupled to the left and right drive wheels W via a differential gear 28 and the like. The torque obtained by adding the drive torque of the engine 10 and the motor torque of the second MG12 is applied to the output shaft 18.
The torque Control device 8 includes a hybrid ecu (electric Control unit)30 and the like.
The hybrid ECU30 is mainly configured by a computer, and includes an execution unit 31 such as a CPU, a storage unit 32 such as a ROM and a RAM, an input/output unit 33, and the like.
To the input/output unit 33 of the hybrid ECU30, an accelerator opening sensor 41 that detects an accelerator opening indicating an amount of operation of an accelerator operation member, not shown, by a driver, a wheel speed sensor 42 that detects a rotational speed of each of 4 wheels including the left and right drive wheels W, a pitch rate sensor 43 that detects a pitch rate d θ p, which is a rotational angular velocity on a spring around an axis extending in the left-right direction passing through the center of gravity of the vehicle, an on-spring acceleration sensor 44 that detects an acceleration Gu in the up-down direction on the spring, and the like are connected, and the engine 10, the inverters 13, 14, and the like are connected. Sprung is the portion of the vehicle supported by the suspension, referred to as the portion containing the body. The vehicle speed Vs, which is the speed of the vehicle body, is obtained based on the wheel speeds Vw of the 4 wheels detected by the wheel speed sensor 42. Further, the detection value of the sprung acceleration sensor 44 is twice integrated, whereby the displacement z in the vertical direction on the spring can be obtained.
The operation of the drive system configured as described above will be described with reference to fig. 2.
In the present embodiment, the operation of the second MG12 as an electric motor is controlled by the control of the inverter 14, and the motor torque of the second MG12 is controlled.
The hybrid ECU30 obtains a vehicle required torque Tsre, which is a driving torque required to drive the vehicle, based on the accelerator opening AP or the like detected by the accelerator opening sensor 41. The vehicle required torque Tsre may be referred to as a driver required torque, for example, when the accelerator opening degree is large, and the vehicle required torque Tsre is larger than when the accelerator opening degree is small.
The engine torque Teg, which is the drive torque output from the engine 10, is obtained based on the vehicle required torque Tsre. The engine torque Teg can be determined to be an optimum level for best fuel economy based on, for example, the vehicle speed Vs obtained from the detection value of the wheel speed sensor 42.
The motor required torque Tmre, which is the required torque for the second MG12, is obtained based on a value obtained by subtracting the engine torque Teg from the vehicle required torque Tsre.
However, the vehicle required torque Tsre is often satisfied by the engine torque Teg. During driving, the second MG12 may be operated when the vehicle required torque Tsre increases or decreases while the engine torque Teg is maintained at a substantially constant value in order to improve fuel economy. Therefore, as shown in fig. 3, the motor required torque Tmre is often determined to be a relatively small value near 0 or 0.
On the other hand, in the torque control device 8, sprung vibration damping control is performed to suppress sprung vibration, that is, sprung vibration. When a disturbance acts on the wheel due to an irregularity of the road surface or the like during the running of the vehicle, the disturbance is transmitted to the spring via the suspension. Thereby, the sprung vibration is in the vicinity of the sprung resonance frequency (e.g., 1.5 Hz). The sprung vibration includes a component in the vertical direction of the position of the center of gravity of the vehicle (referred to as car vibration) and a component in the pitch direction around an axis extending in the horizontal direction through the center of gravity of the vehicle (referred to as pitch vibration).
On the other hand, a part of the torque applied from the drive device 6 to the drive wheels W is converted into a vertical force on the spring by the suspension (mainly, a link mechanism).
Therefore, sprung vibration can be suppressed by controlling the torque applied to the drive wheels W by the drive device 6.
In the sprung vibration damping control, sprung vibration damping torque Tb, which is torque for suppressing sprung vibration, is acquired.
The sprung vibration damping torque Tb can be obtained using, for example, a motion model of sprung vibration that is constructed in advance. When the estimated values of the vehicle required torque Tsre and the torque applied to the drive wheel W are input to the motion model, the vertical displacement z and the pitch displacement θ of the spring, and the rates of change dz/dt and d θ/dt thereof are calculated. Then, correction amounts of the vehicle required torque Tsre are obtained when the calculated vertical displacement z and pitch displacement θ of the spring and their rates of change dz/dt and d θ/dt converge to 0. This correction amount is set as the sprung vibration damping torque Tb. The method of calculating the sprung vibration damping torque Tb is not a feature of the present invention, and therefore, the description thereof is omitted, but the calculation methods described in, for example, japanese patent application laid-open nos. 2010-132254 and 2004-168148 may be applied. Hereinafter, a pitch rate d θ/dt, which is a rate of change in the displacement θ in the pitch direction, may be referred to as d θ p (d θ/dt is d θ p).
The sprung vibration damping torque Tb may be obtained as a torque that offsets actual sprung vertical vibration, for example. The sprung vertical vibration can be represented by, for example, the sprung vertical acceleration Gu detected by the sprung acceleration sensor 44, the pitch rate d θ p detected by the pitch rate sensor 43, and the like. The pitch rate d θ p may be obtained based on the detection value of the wheel speed sensor 46.
In any case, the sprung vibration damping torque Tb may be a torque that changes between a positive value and a negative value centered around 0 as shown in fig. 4, for example. The amplitude of the sprung vibration damping torque Tb may be determined to be a larger value when the amplitude of the sprung vibration is large than when the amplitude of the sprung vibration is small.
In the present embodiment, the sprung vibration damping torque is output by the second MG 12. That is, the target motor torque Tm, which is the target value of the motor torque of the second MG12, is determined to be the magnitude of the sum of the motor required torque Tmre and the value obtained by multiplying the sprung vibration damping torque Tb by the gain G.
Tm*←Tmre+G×Tb
However, when the target motor torque Tm of the second MG12 changes between a positive value and a negative value, in other words, when it is predicted that the motor torque has zero crossing, the tooth hitting sound mainly occurs when the backlash of the reduction gear 26 or the like is clogged. In this way, it is conceivable to prohibit the sprung vibration damping control when the occurrence of the zero crossing in the motor torque is predicted.
However, during high-speed constant-speed running, sprung-up and down vibrations are likely to occur due to irregularities on the road surface of the road, and it is desirable to perform sprung vibration damping control. However, as described above, the motor required torque Tmre is mostly 0 or a value near 0, and when the target motor torque is determined to be the magnitude of the sum of the motor required torque Tmre and the sprung vibration damping torque Tb, the target motor torque normally changes between a positive value and a negative value. Therefore, when the sprung vibration damping control is prohibited when it is predicted that the zero crossing occurs in the motor torque, the sprung vibration damping control is prohibited in most of the high-speed constant-speed running period, and it is difficult to suppress the sprung vibration satisfactorily.
In addition, the weight reduction and the size reduction of the drive device 6 can be achieved along with the weight reduction of the vehicle. As a result, noise generated in the driving device 6 may increase. On the other hand, the sealing property of the vehicle interior is increased, and a higher quietness is required in the vehicle interior. Therefore, it is predicted that the range in which the zero crossing occurs is wide, and the sprung vibration damping control tends to be easily prohibited.
In view of the above, in the torque control device of the present embodiment, the operating frequency of the sprung vibration damping control is increased while suppressing the tooth hitting noise by varying the gain G. The following description is made in detail.
As for the motor required torque Tmre, the absolute value | Tmre |, as shown in fig. 5A, is obtained, and as shown in fig. 5B, an envelope curve as to the sprung vibration damping torque Tb is obtained. The envelope is a curve that shares the target curve group (each curve group of the vibrations of the sprung vibration damping torque Tb) and a tangent line, that is, a curve that is tangent to all the target curve groups. The envelope of the sprung vibration damping torque Tb is a line passing near the maximum value of the sprung vibration damping torque Tb. Therefore, by obtaining the envelope, the amplitude of the sprung vibration damping torque or a value similar to the amplitude can be obtained.
The absolute value | Tmre | of the motor required torque is compared with the value Tbev on the envelope corresponding to the motor required torque Tmre, that is, the absolute value | Tmre | of the motor required torque at the same time is compared with the value Tbev on the envelope.
For example, at time t1, the absolute value Tm1 of the motor required torque is greater than the value Tbev1 on the envelope of the sprung vibration damping torque Tb (Tm1> Tbev1), and at time t2, the absolute value Tm2 of the motor required torque is the same as the value Tbev2 on the envelope of the sprung vibration damping torque Tb (Tm2 ═ Tbev2), but when the absolute value | Tmre | of the motor required torque is equal to or greater than the value Tbev on the envelope as in the period RA of fig. 5A, 5B, and 5C, it is considered that zero crossing hardly occurs even if the sprung vibration damping torque Tb is applied to the motor required torque Tmre. Therefore, when the absolute value | Tmre | of the motor required torque is larger than the value Tbev on the envelope of the sprung vibration damping torque Tb, the gain is determined to be 1 as shown in fig. 5C.
On the other hand, at time t3, for example, the absolute value Tm3 of the motor required torque is smaller than the value Tbev3 on the envelope of the sprung vibration damping torque Tb (Tm3< Tbev 3). As in the period RB in fig. 5A, 5B, and 5C, when the absolute value | Tmre | of the motor required torque is smaller than the value Tbev on the envelope, it is predicted that a zero crossing occurs. Therefore, when the absolute value | Tmre | of the motor required torque is smaller than the value Tbev on the envelope of the sprung vibration damping torque, the gain is set to a value smaller than 1. Specifically, in the period RB in fig. 5A, 5B, and 5C, a ratio γ, which is a value obtained by dividing the absolute value | Tmre | of the motor required torque by the value Tbev on the envelope, is acquired, and the ratio γ is used as a gain. When the absolute value | Tmre | of the motor required torque is 0, the ratio γ becomes 0 and the gain G becomes 0, but when the absolute value | Tmre | of the motor required torque is larger than 0, the gain G becomes a value smaller than 1 and larger than 0.
γ←|Tmre|/Tbev
G←γ
The above operation is represented by the flowchart of fig. 6. The target motor torque determination routine shown in the flowchart of fig. 6 is executed at predetermined set time intervals.
In step 1 (hereinafter, abbreviated as S1, the same applies to the other steps), the vehicle required torque Tsre is acquired, the engine torque Teg is acquired in S2, and the motor required torque Tmre is acquired in S3. On the other hand, in S4, the absolute value | Tmre |, of the motor required torque is acquired, in S5, the sprung vibration damping torque Tb is acquired, and in S6, an envelope is acquired.
Then, in S7, it is determined whether or not the absolute value | Tmre | of the motor required torque is equal to or greater than the value Tbev on the envelope of the sprung vibration damping torque, in other words, whether or not the value obtained by subtracting the value Tbev on the envelope of the sprung vibration damping torque from the absolute value | Tmre | of the motor required torque is equal to or greater than 0. If the determination result is yes, the gain G is set to 1 in S8, and if no, the ratio γ is acquired and set as the gain in S9 and 10.
In S11, the target motor torque Tm is obtained as a value obtained by adding the motor required torque Tmre and a value obtained by multiplying the sprung vibration damping torque Tb by the gain G obtained in S8 or 10. The inverter 14 is controlled so that the motor torque of the second MG12 approaches the target motor torque Tm.
Fig. 7 shows an example of the change in the target motor torque Tm. In the period RA, the absolute value | Tmre | of the motor required torque is equal to or greater than the value Tbev on the envelope of the sprung vibration damping torque Tb, and therefore the gain G is set to 1. The target motor torque Tm changes as indicated by the solid line. In contrast, in the period RB, the absolute value | Tmre | of the motor required torque is smaller than the value Tbev on the envelope of the sprung vibration damping torque Tb, and therefore the gain G is smaller than 1. Therefore, even when the gain G is 1 as shown by the broken line and zero crossing occurs with respect to the target motor torque Tm, the gain G is set to a value smaller than 1, and zero crossing is hard to occur as shown by the solid line.
As described above, in the present embodiment, when the absolute value | Tmre | of the motor required torque is smaller than the value Tbev on the envelope of the sprung vibration damping torque Tb, the gain G is determined to be smaller than 1. As a result, even when the absolute value | Tmre | of the motor required torque is smaller than the value Tbev on the envelope of the sprung vibration damping torque Tb, the sprung vibration damping control can be executed while suppressing the rattling noise. As a result, the frequency of sprung vibration damping control can be increased.
In the present embodiment, it is considered that the amplitude of the sprung vibration damping torque Tb is smaller when the absolute value | Tmre | of the motor required torque is small than when it is large. The amplitude of the sprung vibration damping torque Tb is an amplitude capable of suppressing sprung vibration, that is, an amplitude determined based on the pitch rate d θ p, the sprung vertical acceleration Gu, and the like, that is, a "sprung vibration suppression damping width", but the "sprung vibration suppression amplitude" is corrected and reduced. Therefore, even when the sprung vibration damping control is prohibited to suppress the occurrence of the tooth hitting sound when the gain G is a fixed value of 1, the sprung vibration damping control can be performed while suppressing the occurrence of the tooth hitting sound by correcting the amplitude to a small value.
On the other hand, in the present embodiment, the sprung vibration damping control may be prohibited when the absolute value | Tmre | of the motor required torque is smaller than the prohibition threshold. However, since the gain G is set to be variable and determined to be a value smaller than 1, the number of opportunities to execute sprung vibration damping control while suppressing a tooth hitting sound increases. As a result, the prohibition threshold can be set to a smaller value than in the case where the gain G is fixed to 1.
The gain G is determined based on the difference between the absolute value | Tmre | of the motor required torque and the value Tbev on the envelope of the sprung vibration damping torque Tb, and sprung vibration damping control is performed. Therefore, when the absolute value | Tmre | of the motor required torque is small but the value Tbev on the envelope of the sprung vibration damping torque is small, the gain is set to a value near 1 or 1, and when the absolute value | Tmre | of the motor required torque is large but the value Tbev on the envelope of the sprung vibration damping torque is also large, the gain is set to a value smaller than 1. As a result, as compared with the case where the sprung vibration damping control is always prohibited when the absolute value | Tmre | of the motor required torque is smaller than the prohibition threshold, the operating frequency of the sprung vibration damping control can be increased while suppressing the rattling noise more favorably.
On the other hand, as shown in fig. 5B, the value Tbev on the envelope of the sprung vibration damping torque Tb does not necessarily coincide with the amplitude of the sprung vibration damping torque Tb. When the value of the target motor torque Tm is set to a value near 0 due to a control error or the like, a tooth hitting sound may be generated.
For example, when a value obtained by subtracting the value Tbev on the envelope from the absolute value | Tmre | of the motor request torque is equal to or greater than a set value α indicating the margin, | Tmre | -Tbev ≧ α, the gain is set to 1, and when a value obtained by subtracting the value Tbev on the envelope from the absolute value | Tmre | of the motor request torque is smaller than a set value α, the gain G may be set to a value γ x obtained by dividing the value Tbev on the envelope by the value α from the ratio γ.
G←γx＝(|Tmre|/Tbev)-(α/Tbev)＝(|Tmre|-α)/Tbev
An example of the target motor torque determination routine in this case is shown in the flowchart of fig. 8. In the flowchart of fig. 8, steps that are executed in the same manner as in the case of the flowchart of fig. 6 are denoted by the same step numbers, and description thereof is omitted.
After the absolute value | Tmre | of the motor required torque is acquired and the envelope of the sprung vibration damping torque is acquired, it is determined whether the absolute value | Tmre | of the motor required torque is larger than the set value α in S25, and if it is determined as "no", the gain G is set to 0 in S26, the steps of S25 and S26 are steps for preventing the gain G from being determined as a negative value, and the set value α may be considered as the sprung vibration damping control prohibiting threshold.
If the determination at S25 is "yes", it is determined at S27 whether or not a value obtained by subtracting the value Tbev on the envelope of the sprung vibration damping torque from the absolute value | Tmre | of the motor required torque is equal to or greater than the set value α. if the determination is "yes", the gain is set to 1 at S28, and if the determination is "no", a value γ x obtained by dividing the value obtained by subtracting the set value α from the absolute value | Tmre | of the motor required torque by the value Tbev on the envelope is obtained at S29, 30, the value γ x is set to gain g at S31, in other words, the ratio γ is obtained at S29, and the value γ x obtained by subtracting the set value α from the value on the envelope is obtained at S30.
Thus, in the present embodiment, since the margin is provided, the tooth hitting sound can be suppressed more favorably.
As described above, in the present embodiment, the target motor torque determination unit is configured by the portion of the hybrid ECU30 storing the flowcharts of fig. 6 and 8, the portion executing the flowcharts of fig. 6 and 8, and the like, and the gain determination unit is configured by the portion of the hybrid ECU30 storing S7 to S10 and S25 to S31, the portion of the hybrid ECU executing S7 to S10, and S25 to S31, and the like. The motor required torque determining unit is configured by the portion storing S1 to S3, the portion executing S1 to S3, and the like, the sprung vibration damping torque determining unit is configured by the portion storing S5, the portion executing S5, and the like, the envelope acquiring unit is configured by the portion storing S6, the portion executing S6, and the like, and the ratio acquiring unit is configured by the portion storing S9, S29, the portion executing S9, S29, and the like.
In S25 of the above embodiment, it may be determined whether or not the absolute value | Tmre | of the motor required torque is smaller than the sprung vibration damping control prohibiting threshold, using a value larger than the set value α as the sprung vibration damping control prohibiting threshold, and the sprung vibration damping control prohibiting threshold in this case may be set smaller than the sprung vibration damping control prohibiting threshold set when the gain G is always set to 1.
In the above embodiment, the gain G is determined based on the value obtained by subtracting the value Tbev on the envelope of the sprung vibration damping torque Tb from the absolute value | Tmre | of the motor required torque, but may be determined based on the ratio that is the value obtained by dividing the absolute value | Tmre | of the motor required torque by the value Tbev on the envelope of the sprung vibration damping torque Tb. For example, the gain G may be set to 1 when the ratio is equal to or greater than the set ratio, and the gain G may be set to a value determined based on the ratio when the ratio is smaller than the set ratio. The set ratio may be 1 or a value larger than 1.
In the above embodiment, the case where the torque control device is mounted on the hybrid vehicle has been described, but may be mounted on an electric vehicle, a fuel cell vehicle, or the like. In this way, when the drive device does not include the engine, the motor required torque determined for the electric motor becomes the vehicle required torque.
The present invention can be implemented in various forms other than the above-described embodiments, by implementing various modifications and improvements based on knowledge of those skilled in the art.
Patentable invention
(1) A torque control device that controls torque output from an electric motor by controlling operation of the electric motor of a drive device of a vehicle provided with at least the electric motor, the torque control device comprising: a target motor torque determination unit that determines a target motor torque that is a target value of torque output from the electric motor, based on a magnitude obtained by adding a motor required torque determined based on a vehicle required torque that is torque required to drive the vehicle and a sprung vibration damping torque that is torque for suppressing sprung vibration multiplied by a gain; and a gain determination unit configured to determine the gain to be a smaller value when the absolute value of the motor-requested torque is smaller than the sprung vibration damping torque, as compared to when the absolute value of the motor-requested torque is larger than the sprung vibration damping torque.
The motor required torque may be equal to or smaller than the vehicle required torque. For example, when the drive device includes an engine in addition to the electric motor, a value obtained by subtracting an engine torque, which is a torque output from the engine, from a vehicle required torque may be used as the motor required torque.
The target motor torque may be a value obtained by adding the motor required torque and a value obtained by multiplying the sprung vibration damping torque by a gain, or a value smaller than the added value (for example, a value obtained by multiplying the added value by a coefficient smaller than 1).
Whether or not the absolute value of the motor required torque is smaller than the sprung vibration damping torque may be determined, for example, based on a difference between the absolute value of the motor required torque and the amplitude or a value approximate to the amplitude of the sprung vibration damping torque, or based on a ratio of the absolute value of the motor required torque to the amplitude or the value approximate to the amplitude of the sprung vibration damping torque.
(2) The torque control device according to item (1), wherein, when a value obtained by subtracting a value on an envelope obtained with respect to the sprung vibration damping torque from an absolute value of the motor required torque is small, the gain determining unit determines the gain to be a small value, as compared to when a value obtained by subtracting a value on an envelope obtained with respect to the sprung vibration damping torque from an absolute value of the motor required torque is large.
The envelope of the sprung damping torque approximates a line linking the amplitudes of the sprung damping torque. When the value obtained by subtracting the value on the envelope of the sprung vibration damping torque from the absolute value of the motor required torque at the same timing is small, the zero crossing is more likely to occur than when the value obtained by subtracting the value on the envelope of the sprung vibration damping torque from the absolute value of the motor required torque at the same timing is large. Therefore, it is desirable to determine the gain to be a smaller value when the value obtained by the subtraction is small than when the value obtained by the subtraction is large.
(3) The torque control device according to the item (1) or (2), wherein the gain determination unit sets the gain to 1 when a value obtained by subtracting a value on an envelope acquired for the sprung vibration damping torque from an absolute value of the motor required torque is equal to or greater than a set value, and the gain determination unit determines the gain to a value smaller than 1 based on a ratio obtained by dividing the absolute value of the motor required torque by a value on the envelope acquired for the sprung vibration damping torque when the value obtained by subtracting the value on the envelope acquired for the sprung vibration damping torque from the absolute value of the motor required torque is smaller than the set value.
The set value may be 0 or may be a value larger than 0. By setting the set value to a value greater than 0, the zero crossing can be further suppressed.
The gain can be set to a smaller value when the ratio is small than when it is large. The gain may be set to the same value as the ratio or may be set to a value smaller than the ratio.
(4) The torque control device according to item (3), wherein when the value obtained by subtracting the value on the envelope obtained for the sprung vibration damping torque from the absolute value of the motor required torque is smaller than the set value, the gain determining unit determines the gain as a value obtained by dividing the set value by the value on the envelope obtained for the sprung vibration damping torque from the ratio.
For example, when the set value α is 0, the gain G may be a ratio γ (| Tmre |/Tbev) (G ═ γ), and when the set value α is greater than 0, the gain G may be a value obtained by subtracting a value Tbev on the envelope of the sprung vibration damping torque divided by the set value α from the ratio γ (α/Tbev).
G＝(|Tmre|/Tbev)-(α/Tbev)＝(|Tmre|-α)/Tbev
(5) The torque control device according to any one of the items (1) to (4), wherein the gain determining unit determines the gain to be 0 when an absolute value of the motor required torque is smaller than a sprung vibration damping control prohibiting threshold.
The sprung vibration damping control prohibiting threshold is often set to a magnitude at which the occurrence of the zero crossing is predicted. In contrast, in the torque control device described in this aspect, since the gain is small when the absolute value of the motor required torque is smaller than the sprung vibration damping torque, the sprung vibration damping control prohibiting threshold can be set to a small value. The sprung vibration damping control prohibiting threshold may be, for example, the set value described in the item (3) or (4).
(6) The torque control device according to any one of the items (1) to (5), wherein the drive device includes the electric motor and an engine, and the torque control device includes a motor required torque determination unit that determines the motor required torque based on a value obtained by subtracting an engine torque, which is a drive torque output by the engine, from the vehicle required torque.
When the present torque control device is applied to a torque control device that controls a drive device of a hybrid vehicle, the motor required torque is a value obtained based on a value obtained by subtracting the engine torque from the vehicle required torque. Therefore, the motor required torque is often set to a small value.
(7) The torque control device according to any one of the items (1), (5), and (6), wherein the gain determination unit sets the gain to 1 when a ratio, which is a value obtained by dividing an absolute value of the motor required torque by a value on an envelope of the sprung vibration damping torque, is equal to or greater than a set ratio, and sets the gain to a value smaller than 1 based on the ratio when the ratio is smaller than the set ratio.
(8) A torque control device for controlling a torque output from an electric motor by controlling an operation of the electric motor of a drive device of a vehicle equipped with at least the electric motor, wherein the torque control device includes a target torque determination unit that determines a target motor torque that is a target value of torque output from the electric motor, based on a magnitude obtained by adding a motor required torque and a sprung vibration damping torque that is torque for suppressing sprung vibration, the motor required torque is determined based on a vehicle required torque that is a torque required to drive the vehicle, when the absolute value of the motor required torque is smaller than the sprung vibration damping torque, as compared with when the absolute value of the motor required torque is larger than the sprung vibration damping torque, the target torque determination unit determines the target motor torque by reducing the amplitude of the sprung vibration damping torque.
The torque control device according to the present item may adopt any one of the technical features of the items (1) to (7).
(9) A torque control device for controlling a motor torque, which is a torque output from an electric motor, by controlling an operation of the electric motor of a drive device of a vehicle including the engine and the electric motor, wherein the torque control device includes a target motor torque determination unit that determines a target motor torque that is a target value of the motor torque, based on a magnitude of an addition of a motor request torque and a value obtained by multiplying a sprung vibration damping torque that is a torque for suppressing sprung vibration by a gain, however, when the absolute value of the required motor torque is smaller than the sprung vibration damping control prohibiting threshold, the motor required torque is set to the target motor torque, the motor request torque is determined based on a value obtained by subtracting a drive torque output from the engine from a vehicle request torque that is a torque required to drive the vehicle.
In the hybrid vehicle, the motor required torque is obtained by subtracting the engine torque from the vehicle required torque, and the sprung vibration damping control can be prohibited when the absolute value of the motor required torque is smaller than the prohibition threshold. The gain may be a fixed value or a variable value.
The torque control device according to the present item may adopt the technical features of any one of items (1) to (8).
(10) A drive system, comprising: a drive device provided in a vehicle and including at least an electric motor; and a torque control device that controls a torque output from the electric motor by controlling an operation of the electric motor, wherein the torque control device includes: a target motor torque determination unit that determines a target motor torque that is a target value of torque output from the electric motor, based on a magnitude obtained by adding a motor required torque determined based on a vehicle required torque that is torque required to drive the vehicle and a sprung vibration damping torque that is torque for suppressing sprung vibration multiplied by a gain; and a gain determination unit configured to determine the gain to be a smaller value when the absolute value of the motor-requested torque is smaller than the sprung vibration damping torque, as compared to when the absolute value of the motor-requested torque is larger than the sprung vibration damping torque.
The drive system according to the present item may adopt the technical features of any one of items (1) to (9).
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