阅读说明：本技术 电动悬挂装置 (Electric suspension device ) 是由 大野智史 加藤贵史 丰平朝弥 米田笃彦 于 2020-03-20 设计创作，主要内容包括：本发明提供一种电动悬挂装置,即使是电动马达在其输出容量的界限附近动作的情形,也能够不扰乱车辆的举动且尽可能无损车辆的乘坐舒适性能地实现车辆的振动控制。具有：具备产生涉及到衰减动作及伸缩动作的驱动力的电动马达的电磁致动器、获取电磁致动器的冲程速度的信息获取部、具有对目标衰减力进行计算的衰减力计算部及对目标伸缩力进行计算的伸缩力计算部且求出基于目标衰减力及目标伸缩力得到的目标驱动力的驱动力运算部、和使用目标驱动力进行电动马达的驱动控制的驱动控制部。驱动力运算部具有调整部,该调整部进行基于由信息获取部获取到的冲程速度而降低与目标伸缩力相关的伸缩控制量的调整。(The invention provides an electric suspension device which can realize vibration control of a vehicle without disturbing the behavior of the vehicle and without damaging the riding comfort performance of the vehicle as much as possible even when an electric motor operates near the limit of the output capacity. Comprising: the electromagnetic actuator includes an electric motor that generates a driving force related to a damping operation and a telescopic operation, an information acquisition unit that acquires a stroke speed of the electromagnetic actuator, a driving force calculation unit that has a damping force calculation unit that calculates a target damping force and a telescopic force calculation unit that calculates a target telescopic force and that obtains a target driving force based on the target damping force and the target telescopic force, and a drive control unit that performs drive control of the electric motor using the target driving force. The driving force calculation unit includes an adjustment unit that adjusts an expansion/contraction control amount for reducing the target expansion/contraction force based on the stroke speed acquired by the information acquisition unit.)

1. An electric suspension device, comprising:

an electromagnetic actuator provided between a vehicle body and wheels of a vehicle and including an electric motor that generates a driving force related to a damping operation and a telescopic operation;

an information acquisition unit that acquires information on a stroke speed of the electromagnetic actuator;

a driving force calculation unit that includes a damping force calculation unit that calculates a target damping force that is a target value of a damping operation of the electromagnetic actuator, and an expansion/contraction force calculation unit that calculates a target expansion/contraction force that is a target value of an expansion/contraction operation of the electromagnetic actuator, and that obtains a target driving force that is obtained based on the target damping force calculated by the damping force calculation unit and the target expansion/contraction force calculated by the expansion/contraction force calculation unit; and

a drive control unit that performs drive control of the electric motor using the target drive force obtained by the drive force calculation unit,

the driving force calculation unit includes an adjustment unit that adjusts an expansion/contraction control amount for reducing the target expansion/contraction force based on the stroke speed acquired by the information acquisition unit.

2. The electric suspension device according to claim 1,

the adjustment unit provided in the driving force calculation unit performs adjustment to increase the degree of decrease relating to the expansion/contraction control amount in accordance with an increase in the stroke speed acquired by the information acquisition unit.

3. The electric suspension device according to claim 2,

the adjustment unit provided in the driving force calculation unit performs adjustment for fixing a degree of reduction relating to the expansion/contraction control amount when the stroke speed exceeds a predetermined speed threshold.

4. The electric suspension device according to claim 1,

in the adjustment unit provided in the driving force calculation unit, a characteristic relating to a degree of reduction of the expansion/contraction control amount when the stroke speed is increased and a characteristic relating to a degree of reduction of the expansion/contraction control amount when the stroke speed is decreased are set to be different from each other.

5. The electric suspension device according to claim 1,

the adjustment unit provided in the driving force calculation unit is configured such that a response characteristic when performing adjustment that increases the degree of reduction in the expansion/contraction control amount and a response characteristic when performing adjustment that decreases the degree of reduction in the expansion/contraction control amount are different from each other.

6. The electric suspension device according to claim 5,

in the adjustment unit provided in the driving force calculation unit, the response characteristic when performing the adjustment that reduces the degree of reduction relating to the expansion/contraction control amount is set to be delayed in time from the response characteristic when performing the adjustment that increases the degree of reduction relating to the expansion/contraction control amount.

Technical Field

The present invention relates to an electric suspension device including an electromagnetic actuator provided between a vehicle body and a wheel of a vehicle and including an electric motor generating a driving force related to a damping operation and a telescopic operation.

Background

Conventionally, there is known an electric suspension device including an electromagnetic actuator provided between a vehicle body and a wheel of a vehicle and including an electric motor generating a driving force involved in a damping operation and a telescopic operation (see patent document 1). The electromagnetic actuator has a ball screw mechanism in addition to the electric motor. In the electromagnetic actuator, a rotational motion of an electric motor is converted into a linear motion of a ball screw mechanism. Thus, the electric motor operates to generate a driving force involved in the damping operation and the expansion/contraction operation.

Here, the driving force related to the damping operation means a damping force. The damping force is a force in an upward direction different from a direction of a stroke speed of the electromagnetic actuator. On the other hand, the driving force involved in the telescopic operation means a telescopic force. The extension force refers to an upward force independent of the direction of the stroke speed.

Disclosure of Invention

In the electric suspension device of patent document 1, for example, when a large input is applied such as when the wheel climbs a broken slope, a situation may occur in which the electric motor provided in the electromagnetic actuator operates near the limit of the output capacity thereof. Specifically, in such a case, the electric suspension device causes the electric motor to integrally generate a damping force for buffering a vehicle body pounding phenomenon generated when a large input is applied and an expansion/contraction force for maintaining the vehicle posture in a horizontal state.

However, when the electric motor is operated near the limit of the output capacity thereof, how to distribute the maximum output (maximum driving force) of the electric motor to the damping force and the expansion/contraction force becomes a problem.

If a sufficient damping force cannot be secured, unsprung (wheel) vibration cannot be sufficiently suppressed. As a result, the behavior of the vehicle may be disturbed. In addition, when a sufficient amount of expansion and contraction force cannot be secured, the vehicle cannot be secured in a stable posture by the ceiling control. As a result, the ride comfort of the vehicle is impaired.

In this regard, patent document 1 does not mention how the maximum driving force of the electric motor is distributed as the damping force and the stretching force when the electric motor is operated near the limit of the output capacity.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric suspension device capable of controlling vibration of a vehicle without disturbing vehicle lifting even when an electric motor is operated near the limit of the output capacity thereof, and without impairing the ride comfort performance of the vehicle as much as possible.

In order to achieve the above object, the present invention provides an electric suspension device, which is characterized by comprising: an electromagnetic actuator provided between a vehicle body and wheels of a vehicle and including an electric motor that generates a driving force related to a damping operation and a telescopic operation; an information acquisition unit that acquires information on a stroke speed of the electromagnetic actuator; a driving force calculation unit that includes a damping force calculation unit that calculates a target damping force that is a target value of a damping operation of the electromagnetic actuator, and an expansion/contraction force calculation unit that calculates a target expansion/contraction force that is a target value of an expansion/contraction operation of the electromagnetic actuator, and that obtains a target driving force that is obtained based on the target damping force calculated by the damping force calculation unit and the target expansion/contraction force calculated by the expansion/contraction force calculation unit; and a drive control unit that performs drive control of the electric motor using the target drive force obtained by the drive force calculation unit, wherein the drive force calculation unit includes an adjustment unit that performs adjustment to reduce an expansion control amount related to the target expansion force based on the stroke speed obtained by the information acquisition unit.

Effects of the invention

According to the present invention, even in the case where the electric motor operates near the limit of the output capacity thereof, it is possible to realize vibration control of the vehicle without disturbing the behavior of the vehicle and without impairing the riding comfort performance of the vehicle as much as possible.

Drawings

Fig. 1 is an overall configuration diagram of an electric suspension system according to embodiments 1 and 2 of the present invention.

Fig. 2 is a partial sectional view of an electromagnetic actuator provided in the electric suspension device.

Fig. 3 is a diagram showing the internal and peripheral portions of an ECU provided in the electric suspension device.

Fig. 4A is a diagram conceptually showing the inside of an ECU provided in the electric suspension device according to embodiment 1 of the present invention.

Fig. 4B is an explanatory diagram of a damping force graph conceptually showing a relationship between the target damping force that changes in accordance with the stroke speed.

Fig. 4C is an explanatory diagram of a 1 st decrease rate map conceptually showing a relationship of decrease rates with changes in stroke speed.

Fig. 4D is an explanatory diagram of a2 nd reduction ratio map conceptually showing a case where the characteristic value of the reduction ratio that changes in accordance with the stroke speed follows the hysteresis locus between the increase time and the decrease time of the stroke speed.

Fig. 4E is an explanatory diagram conceptually showing a relationship between the target stretching force before and after adjustment when the adjustment request for reducing the stretching control amount occurs.

Fig. 4F is a diagram conceptually showing the inside of an ECU provided in the electric suspension device according to embodiment 2 of the present invention.

Fig. 5 is a flowchart for explaining the operation of the electric suspension system according to embodiment 1 of the present invention.

Fig. 6A is a timing chart of road surface displacement used for explanation of the operation of the electric suspension device according to embodiment 2.

Fig. 6B is a timing chart of the stroke speed for explaining the operation of the electric suspension device according to embodiment 2.

Fig. 6C is a time chart of the reduction ratio for explaining the operation of the electric suspension device according to embodiment 2.

Fig. 7 is a diagram conceptually showing the inside of an ECU provided in an electric suspension device according to a modification example of embodiment 1 of the present invention.

Fig. 8 is a diagram conceptually showing the inside of an ECU provided in an electric suspension device according to a modification example of embodiment 2 of the present invention.

Description of the reference numerals

10 vehicle

11 electric suspension device

13 electromagnetic actuator

31 electric motor

43 information acquisition unit

47 driving force calculation unit

49 drive control unit

51 damping force calculating part (driving force calculating part)

53 calculation part of extension force (driving force calculation part)

60 reduction ratio calculating section (adjusting section, adjusting section of modified example)

63 control responsiveness calculating section (adjusting section, adjusting section of modification)

65 expansion force correcting part (adjusting part)

67 multiplication operation unit (adjustment unit of modification)

75 adjusting part (driving force calculating part) of embodiment 1

77 adjustment unit (driving force calculation unit) of embodiment 2

Adjustment unit (driving force calculation unit) of modification 85

87 modification example adjustment unit (driving force calculation unit)

SV Stroke velocity

Detailed Description

Hereinafter, the electric suspension system according to embodiment 1 and embodiment 2 of the present invention will be described in detail with reference to the accompanying drawings as appropriate.

In the drawings shown below, the same reference numerals are given to components having common functions. In addition, the size and shape of the components may be distorted or exaggerated schematically for convenience of description.

[ basic constitution common to the electric suspension devices 11 of the 1 st and 2 nd embodiments of the present invention ]

First, a basic configuration common to the electric suspension units 11 according to embodiments 1 and 2 of the present invention will be described with reference to fig. 1 and 2.

Fig. 1 is an overall configuration diagram common to electric suspension units 11 according to embodiments 1 and 2 of the present invention. Fig. 2 is a partial sectional view of the electromagnetic actuator 13 constituting a part of the electric suspension apparatus 11. In the following description, the electric suspension unit 11 according to the embodiment of the present invention will be referred to as an electric suspension unit 11 according to the embodiment of the present invention when the electric suspension unit 11 according to the embodiment of the present invention is referred to as a whole.

As shown in fig. 1, an electric suspension device 11 according to an embodiment of the present invention includes: a plurality of electromagnetic actuators 13 provided to each wheel of the vehicle 10; and an electronic control unit (hereinafter, referred to as "ECU") 15. The plurality of electromagnetic actuators 13 and the ECU15 are connected to each other via an electric power supply line 14 (see the solid line in fig. 1) for supplying drive control electric power from the ECU15 to the plurality of electromagnetic actuators 13 and a signal line 16 (see the broken line in fig. 1) for transmitting a rotation angle signal of the electric motor 31 (see fig. 2) from the plurality of electromagnetic actuators 13 to the ECU 15.

In the present embodiment, the electromagnetic actuators 13 are provided in a total of four on each of the front wheels (left front wheel, right front wheel) and the rear wheels (left rear wheel, right rear wheel). The electromagnetic actuators 13 provided to the respective wheels are driven and controlled independently of each other in accordance with the expansion and contraction operation of each wheel.

In the embodiment of the present invention, the plurality of electromagnetic actuators 13 each have a common configuration, unless otherwise specified. Therefore, the description of the plurality of electromagnetic actuators 13 is replaced by the description of the configuration of one electromagnetic actuator 13.

As shown in fig. 2, the electromagnetic actuator 13 includes a base housing 17, an outer tube 19, a ball bearing 21, a ball screw shaft 23, a plurality of balls 25, a nut 27, and an inner tube 29.

The base housing 17 supports the base end side of the ball screw shaft 23 to be rotatable around the axis via the ball bearing 21. The outer tube 19 is provided in the base case 17 and houses the ball screw mechanism 18 including the ball screw shaft 23, the plurality of balls 25, and the nut 27. The plurality of balls 25 roll along the screw grooves of the ball screw shaft 23. The nut 27 is engaged with the ball screw shaft 23 via the plurality of balls 25, and converts the rotational motion of the ball screw shaft 23 into a linear motion. The inner tube 29 connected to the nut 27 is integrated with the nut 27 and displaced in the axial direction of the outer tube 19.

As shown in fig. 2, the electromagnetic actuator 13 includes an electric motor 31, a pair of pulleys 33, and a belt member 35 in order to transmit a rotational driving force to the ball screw shaft 23. The electric motor 31 is provided in the base case 17 in parallel with the outer tube 19. Pulleys 33 are attached to the motor shaft 31a of the electric motor 31 and the ball screw shaft 23, respectively. A belt member 35 for transmitting the rotational driving force of the electric motor 31 to the ball screw shaft 23 is suspended from the pair of pulleys 33.

The electric motor 31 is provided with a resolver (resolver)37 for detecting a rotation angle signal of the electric motor 31. The rotation angle signal of the electric motor 31 detected by the resolver 37 is sent to the ECU15 via the signal line 16. The electric motor 31 is controlled to be rotationally driven in accordance with drive control electric power supplied from the ECU15 to each of the plurality of electromagnetic actuators 13 via the electric power supply line 14.

In the present embodiment, as shown in fig. 2, the motor shaft 31a of the electric motor 31 and the ball screw shaft 23 are arranged substantially in parallel and coupled to each other, whereby the dimension in the axial direction of the electromagnetic actuator 13 is reduced. However, the motor shaft 31a of the electric motor 31 and the ball screw shaft 23 may be arranged coaxially and coupled to each other.

In the electromagnetic actuator 13 of the present embodiment, as shown in fig. 2, a coupling portion 39 is provided at the lower end portion of the base case 17. The connecting portion 39 is connected and fixed to an unsprung member (a lower arm on the wheel side, a knuckle, and the like) not shown. On the other hand, an upper end portion 29a of the inner tube 29 is fixedly coupled to a sprung member (a strut tower portion on the vehicle body side, etc.), which is not shown.

In short, the electromagnetic actuator 13 is juxtaposed to a spring member, not shown, provided between the vehicle body and the wheels of the vehicle 10. The sprung member is provided with a sprung acceleration sensor 40 (see fig. 3) that detects acceleration of the vehicle body (sprung) along the stroke direction of the electromagnetic actuator 13.

The electromagnetic actuator 13 configured as described above operates as follows. That is, for example, a case is considered in which an urging force relating to upward vibration is input to the coupling portion 39 from the wheel side of the vehicle 10. In this case, the inner tube 29 and the nut 27 are integrally lowered with respect to the outer tube 19 to which the urging force involving the upward vibration is applied. Under this influence, the ball screw shaft 23 rotates in a direction to descend in accordance with the nut 27. At this time, a rotational driving force of the electric motor 31 is generated which hinders the lowering direction of the nut 27. The rotational driving force of the electric motor 31 is transmitted to the ball screw shaft 23 via the belt member 35.

As described above, by applying a reaction force (damping force) against the urging force relating to the upward vibration to the ball screw shaft 23, the vibration to be transmitted from the wheel side to the vehicle body side is damped.

[ internal constitution of ECU15 ]

Next, the configuration of the interior and the peripheral portion of the ECU15 included in the electric suspension unit 11 according to the embodiment of the present invention will be described with reference to fig. 3 and 4A to 4E.

Fig. 3 is a diagram showing the internal and peripheral portions of an ECU15 provided in the electric suspension unit 11 according to the embodiment of the present invention. Fig. 4A is a diagram conceptually showing the inside of the ECU15 included in the electric suspension unit 11 according to embodiment 1 of the present invention. Fig. 4B is an explanatory diagram of an attenuation map table conceptually showing a relationship between the target attenuation force that changes in accordance with changes in the stroke speed SV. Fig. 4C is an explanatory diagram of the 1 st lowering ratio map 61 conceptually showing the relationship of the lowering ratio LR that changes in accordance with changes in the stroke speed SV. Fig. 4D is an explanatory diagram of the 2 nd decrease rate map conceptually showing a case where the characteristic value of the decrease rate LR that changes in accordance with the stroke speed SV follows the hysteresis locus between the increase time and the decrease time of the stroke speed SV. Fig. 4E is an explanatory diagram of the pre-adjustment and post-adjustment target stretching force table 66 conceptually showing the relationship between the pre-adjustment and post-adjustment target stretching force when the adjustment request for reducing the stretching control amount is made.

[ electric suspension device 11 according to embodiment 1 of the present invention ]

The ECU15 included in the electric suspension unit 11 according to embodiment 1 of the present invention is configured to include a microcomputer that performs various arithmetic operations. The ECU15 has a drive control function for generating drive forces for the damping operation and the expansion/contraction operation by individually driving and controlling the plurality of electromagnetic actuators 13 based on a rotation angle signal of the electric motor 31 detected by the resolver 37.

In order to realize such a drive control function, as shown in fig. 3, the ECU15 is configured to include an information acquisition unit 43, a drive force calculation unit 47, and a drive control unit 49.

As shown in fig. 3, the information acquisition unit 43 acquires the rotation angle signal of the electric motor 31 detected by the resolver 37 as the timing information related to the stroke position, and acquires the information of the stroke velocity SV by differentiating the timing information related to the stroke position with time.

Further, as shown in fig. 3, the information acquisition unit 43 acquires time series information related to the sprung acceleration detected by the sprung acceleration sensor 40, and acquires information of the sprung velocity BV by integrating the time series information related to the sprung acceleration.

As shown in fig. 3, the information acquisition unit 43 acquires information on the vehicle speed detected by the vehicle speed sensor 41, information on the yaw rate detected by the yaw rate sensor 42, and information on the motor current supplied to the electric motor 31 to achieve the target driving force related to the electromagnetic actuator 13.

The information on the stroke speed SV, the information on the sprung mass speed BV, and the information on the vehicle speed, the yaw rate, and the motor current acquired by the information acquiring unit 43 are transmitted to the driving force calculating unit 47.

As shown in fig. 4A, the driving force calculation unit 47 includes a damping force calculation unit 51, an expansion/contraction force calculation unit 53, an adjustment unit 75, and an addition calculation unit 57.

The driving force calculation unit 47 basically has the following functions: a target damping force as a target value of the damping operation and a target expansion/contraction force as a target value of the expansion/contraction operation are calculated for the electromagnetic actuator 13, respectively, and a target driving force integrating the target damping force and the target expansion/contraction force is obtained by calculation so as to realize the calculated target damping force and the target expansion/contraction force.

Specifically, the damping force calculation unit 51 included in the driving force calculation unit 47 calculates the value of the target damping force corresponding to the stroke speed SV based on the information of the stroke speed SV acquired by the information acquisition unit 43 and a target damping force map (see fig. 4A and 4B)52 conceptually showing the relationship (target damping force characteristic) between the target damping force changing according to the stroke speed SV. In the target damping force table 52, the target value of the damping force control current is actually stored as a value corresponding to the value of the target damping force.

As shown in fig. 4B, the change region (defined region) of the stroke speed SV in the target damping force map 52 is composed of the 1 st speed region SV1 and the 2 nd speed region SV 2.

The 1 st speed region SV1 is a speed region in which the stroke speed SV converges below the 1 st speed threshold SVth1(| SV-SVth1| ═ 0). The 1 st speed threshold SVth1 is a threshold for dividing a usual speed region among all speed regions of the stroke speed SV. Therefore, the stroke speed SV in the scene of traveling on the ordinary paved road surface almost converges to the 1 st speed region SV 1.

The 2 nd velocity region SV2 is a velocity region in which the stroke velocity SV exceeds the 1 st velocity threshold SVth1(| SV-SVth1| > 0). Therefore, a part of the stroke speed SV generated in a poor traveling scene such as when the wheels of the vehicle 10 go over a hill break reaches the 2 nd speed region SV 2.

The 1 st speed threshold SVth1 may be set to an appropriate value by evaluating a probability density function of the stroke speed SV through experiments, simulations, or the like, referring to the evaluation result, and considering the distribution ratio of the stroke speed SV occurring in each of the 1 st speed region SV1 and the 2 nd speed region SV2, which is a predetermined distribution ratio.

As shown in fig. 4B, the target damping force characteristic of the target damping force map 52 in the 1 st speed region SV1 has the following characteristics: the target damping force directed to the contraction side becomes substantially linearly larger as the stroke speed SV becomes larger toward the expansion side, and the target damping force directed to the expansion side becomes substantially linearly larger as the stroke speed SV becomes larger toward the contraction side. This characteristic is a damping characteristic of a hydraulic damper used in the past. When the stroke speed SV is zero, the target damping force corresponding thereto is also zero.

As shown in fig. 4B, the target damping force characteristic of the target damping force map 52 in the 2 nd velocity region SV2 has the following characteristics: similarly to the target damping force characteristics of the target damping force map table 52 in the 1 st speed region SV1, the target damping force directed to the contraction side increases substantially linearly as the stroke speed SV increases toward the expansion side, and the target damping force directed to the expansion side increases substantially linearly as the stroke speed SV acquired by the information acquisition unit 43 increases toward the contraction side.

However, as shown in fig. 4B, the inclination of the target damping force characteristic of the target damping force graph 52 in the 2 nd velocity region SV2 is set to a gentle inclination characteristic compared to the inclination of the target damping force characteristic of the target damping force graph 52 in the 1 st velocity region SV 1. This characteristic is the damping characteristic of the hydraulic damper used up to now.

On the other hand, the extension/contraction force calculation unit 53 included in the driving force calculation unit 47 calculates a value of the target extension/contraction force corresponding to the sprung velocity BV based on the information of the sprung velocity BV acquired by the information acquisition unit 43 and a target extension/contraction force map (not shown) conceptually showing a relationship of the target extension/contraction force that changes in accordance with the sprung velocity BV (target extension/contraction force characteristics: compliant with skyhook damping control for damping vibration of the sprung member based on the sprung velocity BV). In the target stretching force table, a target value of the stretching force control current is actually stored as a value corresponding to the target stretching force.

The target expansion/contraction force characteristic of the target expansion/contraction force map may be set to an appropriate value obtained by performing an experiment, simulation, or the like for obtaining a target expansion/contraction force corresponding to the sprung velocity BV in order to maintain the posture of the vehicle 10 in a predetermined state.

The target stretching force characteristics of the target stretching force table are not so deeply related to the gist of the present invention, and therefore, the description thereof will be omitted.

Basically, adjustment unit 75 of embodiment 1 provided in driving force calculation unit 47 performs adjustment to reduce the amount of expansion and contraction control based on the target expansion and contraction force in order to properly realize vibration control of vehicle 10 without disturbing the behavior of vehicle 10 and without impairing the ride comfort performance of vehicle 10 as much as possible in the case where electric motor 31 operates near the limit of its output capacity. Here, the degree of reduction of the expansion/contraction control amount means the degree of reduction of the expansion/contraction control amount.

In order to appropriately adjust the reduction amount of the expansion/contraction control, the adjustment unit 75 according to embodiment 1 provided in the driving force calculation unit 47 is configured to include a reduction ratio calculation unit 60 and an expansion/contraction force correction unit 65, as shown in fig. 4A.