JP2011143770A - Suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension device for attaining reduction of a sprung displacement transmission ratio during traveling an uneven road face, prevention of stopper contact during traveling a gradient change road face, and reduction of shock feeling. <P>SOLUTION: When traveling an uneven road face, vibration of a sprung member is restrained by correction active control force f<SB>bfr</SB>*, f<SB>bfl</SB>*, and the sprung displacement transmission ratio is reduced. When traveling a gradient change road face, input from the road face is transmitted to the sprung member at an early timing by correction stroke dumping control force f<SB>sfr</SB>*, f<SB>sfl</SB>* to lower the peak value of the road face input, thus reducing shock feeling. When a vehicle travels the gradient change road face, and when the stroke change amount becomes large, the stroke dumping control becomes dominant, thus increasing resistance force against extension/contraction of an electromagnetic shock absorber device. Generation of stopper contact is effectively prevented by increase of the resistance force. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle suspension apparatus.

  A vehicle suspension device is disposed between a sprung member and an unsprung member of a vehicle, and generates a damping force and a propulsive force for an approaching / separating operation between the sprung member and the unsprung member by expanding and contracting. A shock absorber device is provided. Controlling the damping force and propulsive force generated by the shock absorber device improves the ride comfort of the vehicle.

  Patent Document 1 discloses a semi-active control type suspension device that controls a damping coefficient of a shock absorber device according to a skyhook damper theory. According to the suspension device described in Patent Document 1, when the vibration of the sprung member is large or the relative displacement between the sprung member and the unsprung member is large, the minimum value of the damping coefficient is relatively large. Set to a value. Thus, when the vibration is large, the shock absorber device is set to a relatively hard specification. As a result, a strong damping force (resistance force) acts on excessive vibrations, thereby preventing stopper contact at the limit point of the expansion / contraction stroke of the shock absorber device.

  Patent Document 2 has a power source such as an electric motor, and the power source receives energy supplied from a vehicle-mounted battery or the like to generate a driving force (propulsive force). An active suspension device including an active control type shock absorber device that expands and contracts in the direction of separation and approach is disclosed. According to the active suspension device described in Patent Document 2, when the expansion / contraction stroke of the shock absorber device reaches the vicinity of its terminal end, the control gain of the driving force (propulsion force) decreases, or the expansion / contraction direction of the shock absorber device The shock absorber device is controlled so as to generate a driving force (resistance force) in the opposite direction. Thereby, the resistance to the movement in the end direction increases as the expansion / contraction stroke approaches the end. As a result, the stopper contact at the limit point of the expansion / contraction stroke of the shock absorber device is prevented.

JP-A-10-119528 JP 2000-203933 A

  By the way, the suspension device must control the shock absorber device so as to maintain good riding comfort in response to various changes in the road surface. For example, the road surface shown in FIG. 19 is a road surface on which irregularities smaller than the expansion / contraction stroke range of the shock absorber device are formed. When a vehicle travels on such an uneven road surface, the sprung member may fluctuate due to transmission of wheel vibrations caused by the road surface unevenness to the sprung member. Therefore, it is required to control the driving force generated by the shock absorber device so that the flat feeling of the sprung member is improved, that is, the displacement of the sprung member with respect to the road surface input (sprung displacement transmission ratio) is reduced. Is done. Further, the road surface shown in FIG. 20 is a road surface on which the slope changes, specifically, a road surface that changes from a flat road surface to an uphill road surface. When traveling on such a slope-changing road surface, the shock absorber device prevents the stopper from being touched due to the road surface slope change and reduces the shock feeling generated based on the force that the sprung member receives from the road surface. It is required to control the generated driving force.

  When the control described in Patent Document 1 is applied to an active suspension device, the driving force (propulsive force) generated by the shock absorber device can be controlled so as to prevent contact with the stopper when traveling on a slope changing road surface. . However, when traveling on an uneven road surface, when the amount of relative displacement between the sprung member and the unsprung member increases, the resistance force to the relative movement increases, so the sprung displacement transmission ratio increases. For this reason, a sufficient flat feeling cannot be obtained.

  Further, according to the control described in Patent Document 2, the driving force (propulsive force) generated by the shock absorber device can be actively controlled so as to reduce the sprung displacement transmission ratio when traveling on an uneven road surface. . Further, when the expansion / contraction stroke of the shock absorber device reaches near the end when traveling on a slope changing road surface, the stopper contact is prevented by lowering the control gain. However, when the speed at which the road surface changes up and down is high, that is, when the road surface input is large, even if the control gain is reduced when the expansion / contraction stroke reaches the vicinity of the terminal end, it is already too late and the stopper contact may occur. There is. When the stopper hits, the input from the road surface is instantly transmitted to the sprung member, so that the driver receives a great shock. In addition, when the driving force generated by the shock absorber device is controlled so that a large driving force (resistance force) is generated in the direction opposite to the expansion / contraction direction of the shock absorber device when the stroke reaches the vicinity of its end, Even if there is no contact with the stopper, the driver receives a great shock feeling due to the large driving force in the opposite direction. That is, with the control described in Patent Document 2, it is not possible to sufficiently prevent the occurrence of a hit with a stopper and a great shock feeling during traveling on a slope changing road surface.

  If the telescopic stroke of the shock absorber device is set to a very large value, the stroke amount from when the stroke reaches the vicinity of the end of the shock absorber until the stopper hits can be set large. It is theoretically possible to control so that the stopper contact does not occur even if the gain is lowered. However, increasing the expansion / contraction stroke leads to an increase in the size of the shock absorber device. Therefore, a realistic problem that a failure on mounting occurs.

  As described above, in the conventional active suspension device, the shock absorber is configured so as to achieve both reduction of the sprung displacement transmission ratio when traveling on the uneven road surface, prevention of stopper contact and prevention of generation of a great shock feeling when traveling on the slope changing road surface. The driving force generated by the device cannot be controlled. The reason is that there is a conflict between the requirement to reduce the sprung displacement transmission ratio when traveling on uneven roads and the requirement to prevent contact with the stopper and reduce shock when traveling on gradient road surfaces. .

上記（１）式において、ｍは車両の質量、ｖ_０は車両の速度ベクトルである。一方、図２０に示される勾配変化路面を車両が等速度で走行する場合、勾配変化路面の走行前後における運動量変化は、（２）式のように表される。

上記（２）式において、Ｆは、車両が路面から受ける力（路面入力）を表し、ｖ’は勾配変化路面走行後における車両の速度ベクトル、ｖ_０は勾配変化路面走行前における車両の速度ベクトルであり、｜ｖ’｜＝｜ｖ_０｜である。 When the vehicle travels on the uneven road surface shown in FIG. 19 at a constant speed, the change in the momentum before and after the travel on the uneven road surface is expressed by equation (1).

In the above equation (1), m is the mass of the vehicle, and v ₀ is the velocity vector of the vehicle. On the other hand, when the vehicle travels on the gradient changing road surface shown in FIG. 20 at a constant speed, the change in the momentum before and after traveling on the gradient changing road surface is expressed as in equation (2).

In the above equation (2), F represents the force (road surface input) that the vehicle receives from the road surface, v ′ is the vehicle speed vector after traveling on the slope changing road surface, and v ₀ is the vehicle speed vector before traveling on the slope changing road surface. And | v ′ | = | v ₀ |.

  As can be seen from the equation (1), when the vehicle travels on an uneven road surface, the vehicle does not receive a change in external force (ground load) from the uneven road surface before and after traveling. On the other hand, as can be seen from the equation (2), when the vehicle travels on the gradient changing road surface, the vehicle receives a change in external force (ground load) from the gradient changing road surface before and after traveling. The movement direction of the vehicle changes due to the change in the external force.

  When traveling on an uneven road surface, the change in momentum before and after traveling is not received from the road surface, so that all of the upward and downward displacement of the uneven road surface is controlled by the vertical displacement of only the unsprung member, thereby reducing the on-spring displacement transmission ratio. . That is, the driving force generated by the shock absorber device may be actively controlled so that the vertical displacement of the uneven road surface is absorbed by the vertical displacement of only the unsprung member. This reduces the sprung displacement transmission ratio and improves the flat feeling. However, when such control is applied to a vehicle traveling on a slope-changing road surface, the vehicle is pushed into the slope-changing road surface, and a stopper hit occurs at the end of the expansion / contraction stroke of the shock absorber device. The road surface input is transmitted to the sprung member by a large force accompanied by a shock generated by the stopper. This force changes the direction of travel of the vehicle. In this way, control that emphasizes the improvement of flatness when driving on uneven roads (reduction of the sprung displacement transmission ratio) prevents the occurrence of per-stopper on slope-changed road surfaces, as well as the prevention or mitigation of large shocks. It is not effective control. In addition, when a large driving force (resistance force) is generated in the direction opposite to the expansion / contraction direction of the shock absorber device in order to prevent contact with the stopper, a large shock feeling is generated by the driving force in the reverse direction as described above. End up.

  The present invention has been made to cope with the above-described problem, and in a suspension device including an active control type shock absorber device, the sprung displacement transmission ratio is reduced when traveling on an uneven road surface and when traveling on a slope-changing road surface. It is an object of the present invention to provide a suspension device that achieves both prevention of contact with a stopper and reduction of shock feeling.

  A feature of the present invention is that the sprung member and the unsprung member are arranged between each wheel position of the sprung member of the vehicle and the unsprung member, respectively, and generate a driving force upon receiving energy. In a suspension device that includes a shock absorber device that expands and contracts in the direction of separation and approach, and controls the expansion and contraction operation of the shock absorber device by controlling the driving force, based on a physical quantity related to the vertical movement of the sprung member, Based on an active control amount calculating means for calculating an active control amount corresponding to a driving force to be generated by the shock absorber device in order to suppress the vertical movement of the sprung member, and a physical amount related to the expansion / contraction operation of the shock absorber device In order to suppress the expansion and contraction of the shock absorber device, the shock absorber device should Stroke attenuation control amount calculation means for calculating a stroke attenuation control amount corresponding to the driving force, and stroke attenuation control which is a control gain related to the stroke attenuation control amount as the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device increases. Control gain calculating means for calculating the active control gain and the stroke attenuation control gain so that the gain is relatively large with respect to the active control gain that is a control gain related to the active control amount; and the control gain calculating means By multiplying the stroke control amount calculated by the control gain calculating means and the corrected active control amount calculated by multiplying the active control amount calculated by the active control gain and the stroke attenuation control amount. Calculated Based on the corrected stroke damping control amount, the front wheel side target control amount corresponding to the target value of the driving force generated by the shock absorber device disposed between the front wheel position of the sprung member and the unsprung member is calculated. And a front wheel side target control amount calculating means.

  In this case, the suspension device of the present invention is a pitch suppression control amount calculation means for calculating a pitch suppression control amount corresponding to the driving force to be generated by the shock absorber device in order to suppress the movement of the sprung member around the pitch direction. And the shock absorber disposed between the rear wheel position of the sprung member and the unsprung member based on the active control amount and the pitch suppression control amount calculated by the pitch suppression control amount calculation means. It is preferable to further include rear wheel side target control amount calculation means for calculating a rear wheel side target control amount corresponding to the target value of the driving force generated by the device.

  According to the above invention, it corresponds to the target value of the driving force generated by the shock absorber device disposed between the front wheel position (for example, the left and right front wheel position) of the sprung member and the unsprung member connected to the front wheel. The front wheel side target control amount is calculated based on the corrected active control amount and the corrected stroke attenuation control amount. In this case, the front wheel side target control amount may be calculated based on a control amount obtained by adding the correction active control amount and the correction stroke attenuation control amount. Based on the calculated front wheel side target control amount, the driving force generated by the shock absorber device disposed between the front wheel position of the sprung member and the unsprung member is controlled.

  The corrected active control amount is calculated by multiplying the active control amount by the active control gain, and the corrected stroke attenuation control amount is calculated by multiplying the stroke attenuation control amount by the stroke attenuation control gain. Further, the active control gain and the stroke attenuation control gain are set in advance, for example, so that the stroke attenuation control gain becomes relatively larger than the active control gain as the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device increases. It is calculated according to the control gain characteristic. Therefore, when the ride comfort control of the vehicle is performed by the control by the corrected active control amount (active control) and the control by the corrected stroke damping control amount (stroke damping control), the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device becomes large. As a result, the proportion of stroke attenuation control related to ride comfort control increases. That is, the stroke attenuation control becomes dominant.

  The active control amount is a control amount corresponding to the driving force that should be generated by the shock absorber device in order to suppress the vertical motion of the sprung member due to input from the road surface, that is, to reduce the sprung displacement transmission ratio. In other words, the active control is a control in which the road surface input is not transmitted to the sprung member by actively expanding and contracting the shock absorber device to control the road surface input by the vertical movement of the unsprung member. The stroke attenuation control amount is a control amount corresponding to the driving force that should be generated by the shock absorber device in order to suppress the expansion / contraction operation of the shock absorber device. The force necessary to suppress the expansion / contraction operation of the shock absorber device always acts as a resistance force against the expansion / contraction operation. Therefore, this force is not a force that positively expands / contracts the shock absorber device, but a so-called passive force. It is. In the control by this passive force, the input from the road surface is transmitted to the sprung member. According to the present invention, as the amount of expansion / contraction stroke displacement of the shock absorber device increases, control by passive force becomes dominant. In other words, as the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device increases, the input from the road surface is easily transmitted to the sprung member.

  Thus, according to the present invention, the expansion and contraction operation of the shock absorber device disposed between the front wheel position of the sprung member and the unsprung member is based on the corrected active control amount and the corrected stroke damping control amount. Since the vehicle is controlled based on the calculated front wheel side target control amount, when the vehicle using the control of the present invention travels on the uneven road surface shown in FIG. 19, the corrected active control element included in the front wheel target control amount The sprung displacement transmission ratio is reduced. Further, when traveling on the slope changing road surface shown in FIG. 20, the road surface input is transmitted to the sprung member at an early stage by the corrected stroke attenuation control element included in the front wheel target control amount. This increases the time during which the road surface input is transmitted to the sprung member when traveling on a slope-changing road surface. As a result, the peak of the force received from the road surface is reduced (that is, F is reduced because the integration interval of the equation (2) becomes longer). As a result, it is possible to reduce the magnitude of the shock that is generated when the road surface input is transmitted to the sprung member (that is, the maximum value of F in equation (2)). Further, as the amount of expansion / contraction stroke displacement increases, the stroke damping control becomes dominant, and the resistance force to the expansion / contraction operation of the shock absorber device increases. This increase in the resistance force reliably prevents the stopper contact at the stroke limit position of the shock absorber device. That is, according to the present invention, by appropriately changing the control ratio between the active control and the stroke damping control according to the magnitude of the expansion / contraction stroke displacement amount, it is possible to reduce the sprung displacement transmission ratio when traveling on the uneven road surface, and to change the slope change road surface. It is possible to prevent the occurrence of contact with the stopper and reduce the feeling of shock.

  Further, the rear corresponding to the target value of the driving force generated by the shock absorber device disposed between the rear wheel position of the sprung member (for example, the left and right rear wheel positions) and the unsprung member connected to the rear wheel. The wheel side target control amount is calculated based on the active control amount and the pitch suppression control amount. In this case, the rear wheel side target control amount may be calculated based on a control amount obtained by adding the active control amount and the pitch suppression control amount. Based on the calculated rear wheel side target control amount, the driving force generated by the shock absorber device arranged between the rear wheel position of the sprung member and the unsprung member is controlled.

  The pitch suppression control amount is a control amount corresponding to the driving force that should be generated by the shock absorber device in order to suppress the movement of the sprung member around the pitch direction (around the vehicle width direction axis). By adding the control amount of the pitch direction component to the active control amount and controlling the force generated by the shock absorber device disposed on the rear wheel side of the sprung member, the pitch behavior of the sprung member can be suppressed. .

  As described above, when the vehicle using the control of the present invention travels on the uneven road surface shown in FIG. 19, the sprung displacement transmission ratio is reduced by the modified active control element included in the front wheel side target control amount. When the expansion / contraction stroke displacement amount of the shock absorber device is large, the corrected stroke damping control element included in the front wheel side target control amount becomes dominant, so that the road surface input may be transmitted to the sprung member. At this time, since the pitch behavior of the sprung member is suppressed by the pitch suppression control amount included in the rear wheel side target control amount, the vibration of the sprung member in the pitch direction is suppressed. This improves ride comfort.

  Further, when the vehicle using the control of the present invention travels on the slope changing road surface shown in FIG. 20, for example, only the front wheels approach the slope changing road surface, and the rear wheels are not yet traveling on the slope changing road surface, In order for the sprung member to perform the pitch motion, the driving force generated by the shock absorber device disposed on the rear wheel side of the sprung member is controlled based on the pitch suppression control amount so as to suppress the pitch motion. The force for suppressing the pitch motion acts in the same direction as the direction in which the road surface input is transmitted to the sprung member. As described above, according to the present invention, the road surface on which the rear wheel side travels is predicted in advance (in terms of pre-sensing) based on the difference between the front wheel side motion and the rear wheel side motion (that is, pitch behavior). By generating a force in the direction in which the road surface input is transmitted to the sprung member, the time during which the input from the road surface side is transmitted to the sprung member increases. As a result, the peak of the force received from the road surface decreases (that is, F in equation (2) decreases). Thereby, the magnitude | size of the shock feeling generate | occur | produced when a road surface input is transmitted to a sprung member can be made small.

  Further, a shock absorber device that performs the calculation of the front wheel side target control amount and the calculation of the rear wheel side target control amount as described above and is disposed on the front wheel side of the sprung member based on the calculated front wheel side target control amount is provided. By controlling the driving force generated, and controlling the driving force generated by the shock absorber device disposed on the rear wheel side of the sprung member based on the calculated rear wheel side target control amount, that is, the front wheel side By cooperatively controlling the rear wheel side, it is possible to reliably achieve both reduction of the sprung displacement transmission ratio when traveling on uneven road surfaces, prevention of contact with a stopper when traveling on slope-changing road surfaces, and reduction of shock feeling. In particular, when running on uneven road surfaces, the sprung member may vibrate due to the stroke damping control element of the shock absorber device on the front wheel side. Of this vibration, the pitch vibration is a pitch suppression control element of the shock absorber device on the rear wheel side. It is suppressed by. Since the driver is sensitive to the occurrence of vibration in the pitch direction, the ride comfort is greatly improved by suppressing the vibration in the pitch direction as in the present invention.

  Further, the control gain calculation means is configured such that a stroke attenuation control ratio, which is a control ratio based on the stroke attenuation control amount, becomes a control ratio based on the active control amount as the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device increases. Preferably, the active control ratio and the stroke attenuation control ratio are calculated as the active control gain and the stroke attenuation control gain so as to increase with respect to a certain active control ratio. According to this, the active control ratio and the stroke attenuation control ratio are calculated so that the stroke attenuation control ratio increases as the stroke displacement amount increases. Then, a corrected active control amount is calculated by multiplying the active control ratio by the active control amount, and a corrected stroke attenuation control amount is calculated by multiplying the stroke attenuation control ratio by the stroke attenuation control amount.

  The active control ratio and the stroke attenuation control ratio are control ratios when the control is performed by the control by the active control amount (active control) and the control by the stroke attenuation control amount (stroke attenuation control). That is, the active control ratio is a ratio in which the active control is involved in the control performed by the active control and the stroke attenuation control, and the stroke attenuation control ratio is the stroke attenuation control in the control performed by the active control and the stroke attenuation control. Represents the percentage involved. The sum of the active control ratio and the stroke control ratio is 1.

  In the present invention, when the active control gain is represented as RA (or the active control ratio is R) and the stroke damping control gain is represented as RS (or the stroke damping control ratio is 1-R), the expansion / contraction stroke displacement amount of the shock absorber device is large. As the value increases, RS / RA (or (1-R) / R) increases. In this case, the increasing tendency of RS / RA (or (1-R) / R) may not reach the entire range of the expansion / contraction stroke displacement amount of the shock absorber device, and the stroke displacement amount is at least partially in the range. It is sufficient that RS / RA (or (1-R) / R) increases as the value increases. Preferably, when the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device is equal to or greater than a preset stroke displacement amount, the greater the stroke displacement amount, the greater the RS / RA (or (1-R) / R). ) Should be large. Further, the increasing trend of RS / RA (or (1-R) / R) may be a continuous increasing trend, or a discontinuous or stepwise increasing trend.

  In the present invention, each wheel position of the sprung member means a position where each wheel is attached to the sprung member via the unsprung member and the suspension device. In the case of a general four-wheel vehicle, each wheel position of the sprung member refers to a right front wheel position, a left front wheel position, a right rear wheel position, and a left rear wheel position of the sprung member.

  In the present invention, the active control amount, the stroke attenuation control amount, the pitch suppression control amount, and the target control amount may be the force itself required for each control, or may be an amount corresponding to the force. Further, the shock absorber device of the present invention is a shock absorber device that receives a supply of energy to generate a driving force and can be expanded and contracted by the driving force, that is, a shock absorber device capable of active control. Any power source may be used to generate the force. For example, it may be a shock absorber device that includes an electric motor and generates a rotational driving force by receiving power supply from a battery or the like, and expands and contracts by this rotational driving force, or a hydraulic actuator that includes a hydraulic pump. A shock absorber device that receives an oil pressure to generate an oil pressure and expands and contracts by the generated oil pressure may be used.

  Further, the active control amount is calculated based on a physical quantity related to the vertical movement of the sprung member so that the vertical movement of the sprung member is suppressed. Based on the general skyhook theory, the force required to suppress the upward and downward movement of the sprung member is obtained by multiplying the speed along the vertical direction of the sprung member (sprung vertical speed) by a predetermined gain. Desired. Therefore, the physical quantity related to the vertical motion of the sprung member may be a physical quantity that can obtain the sprung vertical speed, for example, acceleration along the vertical direction of the sprung member (sprung vertical acceleration). The active control amount is based on the sum of a value obtained by multiplying the sprung vertical speed by a predetermined gain and a value obtained by multiplying the unsprung speed (speed along the vertical direction of the unsprung member) by a predetermined gain. You may calculate.

  The suspension device of the present invention may include a sprung vertical acceleration sensor for detecting a sprung vertical acceleration at each wheel position of the sprung member. The sprung vertical acceleration sensor may be attached to each wheel position of the sprung member, but may be attached to at least three positions representing the plane of the sprung member. According to this, the sprung vertical acceleration at each wheel position of the sprung member can be estimated based on the detection signal of each sensor.

  The stroke attenuation control amount is calculated based on a physical quantity related to the expansion / contraction operation of the shock absorber device so that the expansion / contraction operation of the shock absorber device is suppressed. This stroke damping control amount is an amount representing the damping force of the shock absorber device, and the damping force is generally obtained by multiplying the expansion / contraction speed (stroke speed) of the shock absorber device by a predetermined gain (damping coefficient). . Therefore, the physical quantity related to the expansion / contraction operation of the shock absorber apparatus may be a physical quantity that can obtain the stroke speed of the shock absorber apparatus, for example, the stroke displacement amount of the shock absorber apparatus. In this case, the suspension device of the present invention may include a stroke sensor for detecting the expansion / contraction stroke of the shock absorber device disposed between the front wheel position of the sprung member and the unsprung member.

  The pitch suppression control amount is calculated so that the movement of the sprung member around the pitch direction (around the vehicle width direction axis), that is, the pitch behavior is suppressed. This pitch suppression control amount can be expressed, for example, by the difference between the average of the sprung vertical speed on the front wheel side of the sprung member and the average of the sprung vertical speed on the rear wheel side of the sprung member. Therefore, the pitch suppression control amount calculation means calculates the pitch suppression control amount based on the difference between the average sprung vertical speed on the front wheel side of the sprung member and the average sprung vertical speed on the rear wheel side of the sprung member. It is good to calculate.

  Further, the front wheel side target control amount and the rear wheel side target control amount may include other control amounts in addition to the above-described active control amount, stroke attenuation control amount, and pitch suppression control amount. For example, in order to improve the ground contact of the unsprung member, an unsprung control amount calculated based on a physical quantity (for example, unsprung up / down speed) related to the up / down motion of the unsprung member, or a roll motion when the vehicle turns The vehicle is controlled in order to suppress the drivability control amount calculated based on a physical quantity (for example, lateral acceleration) related to the force acting on the vehicle in the lateral direction in order to suppress, or the nose dive or squat when the vehicle is accelerated or decelerated. In addition, an anti-dive / squat control amount calculated based on a physical quantity (for example, longitudinal acceleration) related to a force acting in the front-rear direction may be included in each target control amount.

1 is a schematic view of a vehicle equipped with a suspension device according to the present embodiment. It is the schematic of the system configuration | structure of the suspension apparatus which concerns on this embodiment. FIG. 3 is a partial cross-sectional schematic view of a suspension body. It is a block diagram showing the control structure of the electric motor by a suspension control apparatus and a drive circuit. It is the figure which represented the internal structure of the suspension control apparatus for every function. It is a functional block diagram showing the internal processing of a state quantity calculating part. It is a functional block diagram showing the internal process of an active control force calculating part. It is a functional block diagram showing the internal processing of a stroke damping control force calculating part. It is a functional block diagram showing the internal processing of a pitch suppression control force calculating part. It is a functional block diagram showing the internal processing of the unsprung control force calculating part. It is a functional block diagram showing the internal processing of a control ratio calculating part. It is a functional block diagram showing the internal processing of an arbitration control part. It is a schematic diagram showing that road surface input is transmitted to the sprung member at an early stage through the suspension main body on the front wheel side of the sprung member while traveling on a slope changing road surface. It is a schematic diagram showing that road surface input is transmitted to the sprung member at an early stage through the suspension main body on the rear wheel side of the sprung member while traveling on a slope changing road surface. It is another example of a control ratio characteristic diagram. It is a figure showing the vibration model of a vehicle. It is a schematic diagram showing that force is transmitted to the road surface early from the front wheel side during traveling on a downhill road surface. It is a schematic diagram showing that force is transmitted to the road surface early from the rear wheel side during traveling on the downhill road surface. It is a figure showing an uneven road surface. It is a figure showing a gradient change road surface.

  Hereinafter, a suspension device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a vehicle equipped with a suspension device according to the present embodiment, and FIG. 2 is a schematic diagram of a system configuration of the suspension device according to the present embodiment.

  This suspension device includes suspension bodies 10FR, 10FL, 10RR, 10RL provided between the wheels WFR, WFL, WRR, WRL and the vehicle body B (sprung member), and the suspension bodies 10FR, 10FL, 10RR, 10RL. And a suspension control device 50 for controlling the operation.

  As shown in FIG. 2, the right front wheel suspension body 10FR includes a left front wheel suspension body 10FL between a right front position (right front wheel position) of the vehicle body B and an unsprung member such as a lower arm connected to the right front wheel WFR. Is between the left front position (left front wheel position) of the vehicle body B and the unsprung member connected to the left front wheel WFL, the right rear wheel suspension body 10RR is positioned at the right rear position (right rear wheel position) of the vehicle body B. Between the unsprung member connected to the right rear wheel WRR, the left rear wheel suspension main body 10RL includes a left rear position (left rear wheel position) of the vehicle body B and an unsprung member connected to the left rear wheel WRL. In between, each is arranged. That is, each suspension body is disposed between each wheel position of the sprung member of the vehicle and the unsprung member connected to the wheel corresponding to each wheel position. Hereinafter, when the four sets of suspension bodies 10FR, 10FL, 10RR, 10RL and the wheels WFR, WFL, WRR, WRL are collectively referred to, they are simply referred to as the suspension body 10 and the wheels W.

  FIG. 3 is a partial cross-sectional schematic view of the suspension body 10. As shown in FIG. 3, the suspension body 10 includes a coil spring 20 and an electromagnetic shock absorber device 30. The coil spring 20 absorbs an impact received from the road surface by using its own elasticity, enhances the ride comfort, and elastically supports the weight of the vehicle. The side supported by the coil spring 20, that is, the vehicle body B side member is a sprung member, and the side that supports the coil spring 20, that is, the wheel W side member is an unsprung member.

  The electromagnetic shock absorber device 30 is disposed in parallel with the coil spring 20 between each wheel position of the sprung member and the unsprung member. The electromagnetic shock absorber device 30 includes an electric motor 31 and a ball screw mechanism 32. The electric motor 31 includes a motor casing 311, a hollow rotating shaft 312, a permanent magnet 313, and a pole body 314. The motor casing 311 is a housing that constitutes the outline of the electric motor 31, and has a stepped cylindrical shape having a shaft in the vertical direction in the figure and gradually decreasing in diameter from the top. The rotating shaft 312 is disposed in the motor casing 311 coaxially with the motor casing 311, and is rotatably supported by the motor casing 311 by bearings 331 and 332. A permanent magnet 313 is fixed to the outer peripheral surface of the rotating shaft 312. The rotating shaft 312 and the permanent magnet 313 constitute a rotor of the electric motor 31. A pole body 314 (with a coil wound around a core) is fixed to the inner peripheral surface of the motor casing 311 so as to face the permanent magnet 313. The pole body 314 constitutes the stator of the electric motor 31.

  The ball screw mechanism 32 is connected to the electric motor 31 and has a function as a conversion mechanism that converts the rotational motion of the electric motor 31 into linear motion. The ball screw mechanism 32 includes a ball screw shaft 321 in which a screw groove 321 a is formed, and a ball screw nut 322 that is screwed into the screw groove 321 a of the ball screw shaft 321. The ball screw nut 322 is disposed in the motor casing 311, is connected to the lower end portion of the rotating shaft 312, and is supported by the motor casing 311 via a ball bearing so as to be rotatable and not movable in the axial direction. Therefore, when the rotating shaft 312 rotates, the ball screw nut 322 rotates accordingly.

  As shown in the drawing, the ball screw shaft 321 is coaxially disposed in the motor casing 311, and the ball screw nut 322 is screwed into the motor casing 311, and the inner periphery of the rotating shaft 312 is located at an upper portion thereof. Inserted in the side. Further, the lower portion of the ball screw shaft 321 penetrates the lower end surface of the motor casing 311 and extends further downward.

  A spline nut 35 is disposed below the ball screw nut 322 in the figure. The spline nut 35 is disposed and fixed at the lowermost portion of the motor casing 311. The spline nut 35 is provided with a through hole in which a spline is formed, and the ball screw shaft 321 is inserted into the through hole. A spline groove is also formed in the screw groove 321a of the ball screw shaft 321 at the same time. Accordingly, the ball screw shaft 321 is spline-fitted to the spline nut 35 and supported by the spline nut 35 so as not to rotate but to move in the axial direction.

  A hydraulic damper device 40 is disposed below the electromagnetic shock absorber device 30 in the figure. The hydraulic damper device 40 is disposed between the electromagnetic shock absorber device 30 and the unsprung member so as to be connected in series to the electromagnetic shock absorber device 30. The hydraulic damper device 40 includes a housing 41 in which a working fluid (for example, working oil) is sealed, and a valve piston 42 that is disposed inside the housing 41 and moves relative to the housing 41. The interior of the housing 41 is partitioned into an upper chamber and a lower chamber by the valve piston 42. The lower end of the housing 41 is connected to a lower arm, which is an unsprung member, via a bush.

  In the present embodiment, the hydraulic damper device 40 is a twin tube type shock absorber device, and includes an outer cylinder 411 and an inner cylinder 412 in which a housing 41 is coaxially arranged. A reservoir chamber is formed by the space between the outer cylinder 411 and the inner cylinder 412. The valve piston 42 is disposed in the inner cylinder 412. When the valve piston 42 moves in the inner cylinder 412 in the axial direction, the working fluid flows between the upper chamber and the lower chamber. ) Occurs. A base valve 413 is attached to the lower end of the inner cylinder 412, and the lower chamber communicates with the reservoir chamber via the base valve 413. As the valve piston 42 moves, the hydraulic fluid flows between the lower chamber and the reservoir chamber, whereby a resistance force (attenuating force) depending on the viscosity of the hydraulic fluid is generated with respect to the movement. That is, the hydraulic damper device 40 generates a damping force based on the viscosity of the hydraulic fluid.

  A piston rod 43 is inserted into the inner cylinder 412. The piston rod 43 is connected to the valve piston 42 at its lower end. The piston rod 43 is connected to the lower end of the ball screw shaft 321 at its upper end, extends downward in the figure from the connected portion, and is inserted into the inner cylinder 412 from the upper surface side of the housing 41 of the hydraulic damper device 40. Therefore, the valve piston 42 is connected to the ball screw shaft 321 of the electromagnetic shock absorber device 30 via the piston rod 43. In this way, the hydraulic damper device 40 is connected in series with the electromagnetic shock absorber device 30.

  An annular lower retainer 44 a is provided on the outer peripheral portion of the outer cylinder 411 of the hydraulic damper device 40. The cylinder part 21 is connected to the outer periphery of the lower retainer 44a. The cylindrical portion 21 extends upward in the drawing so as to cover the housing 41 of the hydraulic damper device 40 from a portion connected to the lower retainer 44a. A flange portion 211 that is bent radially inward is formed at the upper end portion of the cylindrical portion 21. An annular upper retainer 44 b is provided on the lower surface side of the flange portion 211.

  A central retainer 44 c is attached to a connecting portion between the ball screw shaft 321 and the piston rod 43. The central retainer 44c includes a disk-shaped portion 44c1 extending radially from the connecting portion between the ball screw shaft 321 and the piston rod 43, and a cylindrical portion 44c2 extending downward from the outer periphery of the disk-shaped portion 44c1. And an annular flange portion 44c3 extending radially outward from the cylindrical portion 44c2. A first coil spring 46a is disposed between the flange portion 44c3 and the lower retainer 44a of the central retainer 44c having such a shape, and a second coil spring 46b is disposed between the flange portion 44c3 and the upper retainer 44b.

  The hydraulic damper device 40 having such a configuration operates when high-frequency vibration (for example, 20 Hz or more) is input from the road surface side. That is, the housing 41 moves relative to the valve piston 42 when high-frequency vibration is input from the road surface. The high-frequency vibration is attenuated by the damping force generated by this relative movement. When other vibrations are input from the unsprung member side or the sprung member side, or when the electromagnetic shock absorber device 30 is actively expanded and contracted, the hydraulic damper device 40 does not operate in principle. (The housing 41 and the valve piston 42 are not relatively displaced). In short, the hydraulic damper device 40 serves as a high frequency vibration filter.

  A retainer 212 is formed on the outer periphery of the cylindrical portion 21. The lower end of the coil spring 20 is connected to the retainer 212. The upper end of the coil spring 20 is connected to a retainer 213 formed on the lower surface of the bracket 25 in the figure.

  The suspension body 10 is disposed such that the upper portion of the motor casing 311 of the electric motor 31 protrudes upward from a hole formed in the vehicle body B, and the upper support 12 is maintained so as to maintain such an arrangement state. It is attached to the vehicle body B via. The upper support 12 includes a resin member 121 and a bracket 122, and elastically connects the suspension body 10 to the vehicle body B.

  In the suspension body 10 configured as described above, the electric motor 31 of the electromagnetic shock absorber device 30 generates a rotational driving force by supplying power from a battery power source or the like. Then, the ball screw nut 322 connected to the rotating shaft 312 of the electric motor 31 rotates. As the ball screw nut 322 rotates, the ball screw shaft 321 and the hydraulic damper device 40 connected to the ball screw shaft 321 move in the axial direction. As a result, the electromagnetic shock absorber device 30 expands and contracts. The axial direction of the ball screw shaft 321 is the same as the approach / separation direction (vertical direction) between the sprung member and the unsprung member. Therefore, the electromagnetic shock absorber device 30 actively expands and contracts in the approaching / separating direction between the sprung member and the unsprung member by the rotational driving force generated by the electric motor 31. By the expansion and contraction operation of the electromagnetic shock absorber device 30, the sprung member and the unsprung member relatively move in the approaching / separating direction.

  When an external force (such as road surface input) is applied to the suspension body 10, the external force moves the ball screw shaft 321 of the electromagnetic shock absorber device 30 in the axial direction. As the ball screw shaft 321 moves in the axial direction, the electromagnetic shock absorber device 30 expands and contracts. Along with this expansion and contraction, the sprung member and the unsprung member relatively move in the approaching / separating direction and the ball screw nut 322 rotates. The electric motor 31 is rotated by the rotation of the ball screw nut 322. At this time, the electric motor 31 acts as a generator and generates a resistance force due to power generation. Thus, the electromagnetic shock absorber device 30 generates a driving force (damping force) that opposes the expansion and contraction operation by an external input.

  As shown in FIG. 2, the suspension control device 50 is mounted on the vehicle body B. The suspension control device 50 controls the expansion / contraction operation of each electromagnetic shock absorber device 30 by controlling the driving force generated by the electric motor 31 provided in the electromagnetic shock absorber device 30 of each suspension body 10. Each suspension control device 50 is connected to each sprung vertical acceleration sensor 61, each unsprung vertical acceleration sensor 62, and each stroke sensor 63. The sprung vertical acceleration sensor 61 is placed at each wheel position of the sprung member and detects a signal corresponding to acceleration (sprung vertical acceleration) acting in the vertical direction on each wheel position of the sprung member. The detected signal is output to the suspension control device 50. The unsprung vertical acceleration sensor 62 is mounted on an unsprung member such as a lower arm to which each suspension body 10 is attached, and outputs a signal corresponding to an acceleration (unsprung vertical acceleration) acting in the vertical direction on the unsprung member. The detected signal is output to the suspension control device 50. The stroke sensor 63 is attached in the vicinity of the front suspension body (the right front wheel suspension body 10FR and the left front wheel suspension body 10FL), and corresponds to the amount of expansion / contraction stroke displacement of the electromagnetic shock absorber device 30 of these suspension bodies. The signal is detected by, for example, a change in the angle of the lower arm, and the detected signal is output to the suspension control device 50.

The suspension control device 50 is mainly composed of a microcomputer. The suspension control device 50 has a target control force (a target value of a force generated by the electric motor 31 of each electromagnetic shock absorber device 30 disposed between each wheel position of the sprung member and the unsprung member ( Right front wheel target control force F _fr , left front wheel target control force F _fl , right rear wheel target control force F _rr , left rear wheel target control force F _rl ) are calculated. The suspension control device 50 outputs a control signal corresponding to the calculated target control force to the drive circuit 70 corresponding to each electromagnetic shock absorber device 30. Each drive circuit 70 is connected to each electric motor 31 of the corresponding electromagnetic shock absorber device 30 and controls the electric motor 31 based on the input control signal.

  FIG. 4 is a block diagram illustrating a control configuration of the electric motor 31 by the suspension control device 50 and the drive circuit 70. As shown in the figure, the suspension control device 50 controls the driving force of the electric motor 31 via the drive circuit 70. The drive circuit 70 constitutes a three-phase inverter circuit, and switching elements SW11, SW12, SW21, respectively corresponding to the three-phase electromagnetic coils CL1, CL2, CL3 of the electric motor 31 (a three-phase brushless motor is used in this embodiment). SW22, SW31, SW32. These switching elements are duty-controlled based on a control signal input from the suspension control device 50 (PWM control). As a result, the amount of current supplied from the battery to the electric motor 31 and the amount of regenerative power sent from the electric motor 31 to the battery are controlled.

  FIG. 5 is a diagram showing the internal configuration of the suspension control device 50 for each function. As shown in the figure, the suspension control device 50 includes a state quantity calculation unit 51, an active control force calculation unit 52, a stroke damping control force calculation unit 53, a pitch suppression control force calculation unit 54, an unsprung control force as functional blocks. A calculation unit 55, a control ratio calculation unit 56, and an arbitration control unit 57 are provided. The state quantity calculation unit 51 is based on signals obtained from various sensors, the movement state quantity related to the vertical movement at each wheel position of the sprung member of the vehicle, the movement state quantity related to the vertical movement of each unsprung member, The amount of motion state related to the expansion / contraction operation of each electromagnetic shock absorber device 30 is calculated.

FIG. 6 is a functional block diagram showing internal processing of the state quantity calculation unit 51. As shown in the figure, the state amount calculation unit 51 receives signals detected by the sprung vertical acceleration sensors 61, the unsprung vertical acceleration sensors 62, and the stroke sensors 63, respectively. The state quantity calculation unit 51 calculates the sprung vertical acceleration x _bi ″ at each wheel position of the sprung member based on the signal detected by each sprung vertical acceleration sensor 61. Here, the sprung vertical acceleration is calculated. The subscript i of the reference sign x _bi "represents the position of each ring of the sprung member. Therefore, the subscript i is any one of the right front wheel position fr, the left front wheel position fl, the right rear wheel position rr, and the left rear wheel position rl. In other words, the state quantity calculation unit 51 determines, based on the signals detected by the sprung vertical acceleration sensors 61, the sprung vertical acceleration at the right front wheel position (right front wheel sprung vertical acceleration) _xbfr ", the spring at the left front wheel position. Upper vertical acceleration (upper vertical acceleration on the left front wheel spring) x _bfl ", Upper vertical acceleration on the right rear wheel position (upper vertical acceleration on the right rear wheel spring) x _brr ", Upper vertical acceleration on the left rear wheel position (left rear wheel) The sprung vertical acceleration) x _brl "is calculated. In the following description, the role of the subscript i is the same.

In addition, the state quantity calculation unit 51 integrates each sprung vertical acceleration x _bi ″, so that the sprung vertical speed x _bi ′ (the right front wheel spring) is the speed along the vertical direction of the sprung member at each wheel position. Upper vertical speed x _bfr ', left front wheel spring vertical speed x _bfl ', right rear wheel spring vertical speed x _brr ', left rear wheel spring vertical speed x _brl '). By integrating x _bi ′, each sprung vertical displacement amount x _bi (right front wheel sprung vertical displacement amount x _bfr , left ₎ , which is a displacement amount from the reference position along the vertical direction of the sprung member at each wheel position, is _obtained . The front wheel spring up / down displacement amount _xbfl , the right rear wheel spring up / down displacement amount _xbrr , and the left rear wheel spring up / down displacement amount _xbrl ) are calculated.

Further, the state quantity calculation unit 51 operates in the vertical direction on the unsprung member connected to each wheel position of the sprung member via the suspension body 10 based on the signal input from each unsprung vertical acceleration sensor 62. unsprung to vertical acceleration _{x wi} "(under the right front wheel spring vertical acceleration _{x wfr",} under the left front wheel spring vertical acceleration _{x wfl ",} the right rear wheel unsprung vertical acceleration _{x wrr",} the left rear wheel unsprung vertical acceleration _{x wrl} " Further, by integrating the unsprung vertical acceleration x _wi ″, the unsprung vertical speed x _wi ′ (the right front wheel unsprung vertical speed x _wfr ′), which is the speed along the vertical direction of each unsprung member, is calculated. , Left front wheel unsprung vertical speed x _wfl ′, right rear wheel unsprung vertical speed x _wrr ′, left rear wheel unsprung vertical speed x _wrl ′). Further, by integrating the unsprung vertical velocity x _wi ′, the unsprung vertical displacement amount x _wi (the right front wheel unsprung vertical displacement amount x _wfr ), which is the displacement amount from the reference position along the vertical direction of each unsprung member. , Left front wheel unsprung vertical displacement x _wfl , right rear wheel unsprung vertical displacement x _wrr , left rear wheel unsprung vertical displacement x _wrl ). In calculating the sprung vertical acceleration x _bi ″ and the unsprung vertical acceleration x _wi ″, the state quantity calculation unit 51 calculates the upward acceleration as a positive acceleration and the downward acceleration as a negative acceleration. Calculate as acceleration. In calculating the sprung vertical speed x _bi ′ and the unsprung vertical speed x _wi ′, the upward speed is calculated as a positive speed, and the downward speed is calculated as a negative speed.

In addition, the state quantity calculation unit 51 calculates the expansion / contraction stroke displacement amount of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR based on the signals detected by the stroke sensors 63 provided on the front wheel side of the sprung member. A right front wheel stroke displacement amount x _sfr and a left front wheel stroke displacement amount x _sfl representing the expansion stroke displacement amount of the electromagnetic shock absorber device 30 of the left front wheel suspension body _10FL are calculated. These stroke displacement amounts represent an amount (amount of expansion / contraction) in which the length of the electromagnetic shock absorber device 30 has changed from a predetermined reference length. Further, the state quantity calculation unit 51 differentiates the right front wheel stroke displacement amount x _sfr and the left front wheel stroke displacement amount x _sfl , respectively, to thereby express the right front wheel representing the expansion / contraction speed of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR. The stroke speed x _sfr ′ and the left front wheel stroke speed x _sfl ′ representing the expansion / contraction speed of the electromagnetic shock absorber device 30 of the left front wheel suspension body 10FL are calculated. Note that, when calculating each stroke speed, the state quantity calculation unit 51 calculates the stroke speed in the extension direction as a positive speed and calculates the stroke speed in the contraction direction as a negative speed.

Based on the sprung vertical speed x _bi ′ at each wheel position of the sprung member, the active control force calculating unit 52 controls the electromagnetic shock absorber device 30 to suppress the vertical movement at each wheel position of the sprung member. A driving force (active control force) to be output by the electric motor 31 is calculated. FIG. 7 is a functional block diagram showing internal processing of the active control force calculation unit 52. The active control force calculation unit 52 inputs each sprung vertical speed x _bi ′ calculated by the state quantity calculation unit 51. Further, the active control force calculation unit 52 calculates the right front wheel active control force f _bfr by multiplying the input right front wheel sprung vertical speed x _bfr ′ by a negative gain −K _bfr , and the left front wheel sprung vertical speed x _The left front wheel active control force _fbfl is calculated by multiplying _bfl 'by a negative gain _-Kbfl , and the right rear wheel active control force is calculated by multiplying the right rear wheel sprung vertical speed _xbrr ' by a negative gain _-Kbrr. The force _fbrr is calculated, and the left rear wheel active control force _fbrl is calculated by multiplying the left rear wheel sprung vertical speed _xbrl 'by a negative gain _-Kbrl . The right front wheel active control force f _bfr corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR should output in order to suppress the vertical movement of the sprung member at the right front wheel position. The left front wheel active control force f _bfl corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the left front wheel suspension body 10FL should output in order to suppress the vertical movement of the sprung member at the left front wheel position. The right rear wheel active control force _fbrr is a driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the right rear wheel suspension body 10RR should output in order to suppress the vertical movement of the sprung member at the right rear wheel position. Equivalent to. The left rear wheel active control force _fbrl is a driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the left rear wheel suspension body 10RL should output in order to suppress the vertical movement of the sprung member at the left rear wheel position. Equivalent to.

The stroke damping control force calculation unit 53 is configured to suppress the expansion / contraction operation of the electromagnetic shock absorber device 30 based on the stroke speed of the electromagnetic shock absorber device 30 of the suspension body 10 on the front wheel side. The driving force (stroke damping control force) to be output by the 30 electric motors 31 is calculated. FIG. 8 is a functional block diagram showing the internal processing of the stroke damping control force calculation unit 53. The stroke damping control force calculation unit 53 inputs the right front wheel stroke speed x _sfr ′ and the left front wheel stroke speed x _sfl ′ calculated by the state quantity calculation unit 51. The right front wheel stroke speed x _sfr is multiplied by a negative gain (attenuation coefficient) −C _fr to obtain the right front wheel stroke damping control force f _sfr and the left front wheel stroke speed x _sfl as a negative gain (attenuation coefficient) −C _The left front wheel stroke damping control force f _sfl is calculated by multiplying by _fl , respectively. The right front wheel stroke damping control force f _sfr corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 should output in order to suppress the expansion and contraction operation of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR. . The left front wheel stroke damping control force f _sfl corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 should output in order to suppress the expansion and contraction operation of the electromagnetic shock absorber device 30 of the left front wheel suspension body 10FL. .

The pitch suppression control force calculator 54 is a driving force (pitch) to be output by the electric motor 31 of the electromagnetic shock absorber device 30 of each suspension body 10 in order to suppress the movement of the sprung member around the pitch direction (pitch movement). (Suppression control force) is calculated. FIG. 9 is a functional block diagram showing internal processing of the pitch suppression control force calculation unit 54. The pitch suppression control force calculator 54 receives the sprung vertical speed x _bi ′ at each wheel position of the sprung member calculated by the state quantity calculator 51. Then, the front right wheel upper sprung vertical speed x _bfr ′ and the left front wheel sprung vertical speed x _bfl ′ are added and divided by two to calculate the front wheel upper sprung vertical average speed x _bF ′. Further, by adding the input right rear wheel sprung vertical speed _xbrr 'and the left rear wheel sprung vertical speed _xbrl ' and dividing by 2, the rear wheel side sprung vertical average speed _xbR 'is calculated. Furthermore, by subtracting the rear wheel _'on the front-wheel-side spring from the upper and lower average speed x _bF' side on the upper and lower average speed x _bR spring, _'computes, the pitch rate x _p' pitch rate x _p multiplied by the gain K _p to it allows calculating a pitch restraining force f _p.

The pitch reduction control force calculating unit 54, by multiplying the 1 on the calculated pitch restraining force f _p, calculates the right front wheel pitch reduction control force f _pfr and the left front wheel pitch reduction control force f _pfl, computed pitch control By multiplying the force f _p by −1, the right rear wheel pitch suppression control force f _prr and the left rear wheel pitch suppression control force f _prl are calculated. The right front wheel pitch suppression control force f _pfr is a driving force to be output by the electric motor 31 of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR in order to suppress the movement of the sprung member around the pitch direction (pitch movement). It corresponds to. Left front wheel pitch reduction control force f _pfl corresponds to the driving force to be output by the electric motor 31 of the left front wheel suspension body 10FL electromagnetic shock absorber device 30 in order to suppress the pitch motion of the sprung member. The right rear wheel pitch suppression control force f _prr corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the right rear wheel suspension body 10RR should output in order to suppress the pitch motion of the sprung member. The left rear wheel pitch suppression control force f _prl corresponds to a driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the left rear wheel suspension body 10RL should output in order to suppress the pitch motion of the sprung member.

The unsprung control force calculation unit 55 should output the electric motor 31 of the electromagnetic shock absorber device 30 of each suspension body 10 based on each unsprung speed x _wi ′ so that each wheel W contacts the road surface. The driving force (unsprung control force) is calculated. FIG. 10 is a functional block diagram showing the internal processing of the unsprung control force calculation unit 55. The unsprung control force computing unit 55 inputs each unsprung vertical speed x _wi ′ computed by the state quantity computing unit 51. The right front wheel unsprung control force f _wfr is calculated by multiplying the input right front wheel unsprung vertical speed x _wfr ′ by a positive gain K _wfr , and the input left front wheel unsprung vertical speed x _wfl ′ is a positive gain. By multiplying K _wfl , the left front wheel unsprung control force f _wfl is calculated, and by multiplying the input right rear wheel unsprung vertical speed x _wrr ′ with a positive gain K _wrr , the right rear wheel unsprung control force f _wrr is obtained. The left rear-wheel unsprung control force f _wrl is calculated by multiplying the inputted left rear-wheel unsprung vertical speed x _wrl ′ with a positive gain K _wrl . The right front wheel unsprung control force _fwfr corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR should output so that the right front wheel WFR _{contacts the} road surface. The left front wheel unsprung control force _fwfl corresponds to the driving force to be output by the electric motor 31 of the electromagnetic shock absorber device 30 of the left front wheel suspension body 10FL so that the left front wheel WFL is in contact with the road surface. The right rear wheel unsprung control force f _wrr corresponds to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 of the right rear wheel suspension body 10RR should output so that the right rear wheel WRR contacts the road surface. The left rear wheel unsprung control force f _wrl corresponds to the driving force to be output by the electric motor 31 of the electromagnetic shock absorber device 30 of the left rear wheel suspension body 10RL so that the left rear wheel WRL _{contacts the} road surface.

FIG. 11 is a functional block diagram showing internal processing of the control ratio calculation unit 56. The control ratio calculation unit 56 inputs the right front wheel stroke displacement amount x _sfr and the left front wheel stroke displacement amount x _sfl calculated by the state amount calculation unit 51. In addition, a control ratio characteristic diagram 561 is stored in the control ratio calculation unit 56 in advance. This control ratio characteristic diagram 561 is a diagram showing the relationship between the stroke displacement amount of the electromagnetic shock absorber device 30 and the active control ratio R. The active control ratio R is the control by each active control force calculated by the active control force calculation unit 52 (active control) and the control by each stroke damping control force calculated by the stroke damping control force calculation unit 53 ( In the case where the control is performed by the stroke attenuation control), it represents the ratio of the active control involved in the control. Further, a ratio (1-R) obtained by subtracting the active control ratio R from 1 represents a ratio in which the stroke attenuation control is involved in the control when the control is performed by the active control and the stroke attenuation control. That is, the ratio (1-R) is a stroke attenuation control ratio. If the active control ratio R increases, the stroke damping control ratio (1-R) decreases. The sum of the active control ratio R and the stroke attenuation control ratio (1-R) is 1 (100%).

  The active control ratio R changes according to the amount of stroke displacement of the electromagnetic shock absorber device 30 as shown in the control ratio characteristic diagram 561. The horizontal axis of the control ratio characteristic diagram 561 is the absolute value of the stroke displacement amount, and the vertical axis is the magnitude of the active control ratio R. Regarding the stroke displacement amount, the stroke displacement amount when the length of the electromagnetic shock absorber device 30 is the reference length is 0, and the length of the electromagnetic shock absorber device 30 is increased (elongated) from the reference length. The stroke displacement amount increases in the positive direction (that is, as the pull-out amount increases), and the length of the electromagnetic shock absorber device 30 decreases (shrinks) from the reference length (that is, as the pull-in amount increases). Stroke displacement increases in the negative direction. In the control ratio characteristic diagram 561 shown in FIG. 11, the maximum stroke displacement amount is set to 80 mm.

  The active control ratio R is larger than 0 (0%) and smaller than 1 (100%) in the change range of the stroke displacement amount. The active control ratio R decreases as the absolute value of the stroke displacement amount increases. In other words, the stroke attenuation control ratio (1-R) increases relative to the active control ratio R as the absolute value of the stroke displacement amount increases. Specifically, when the absolute value of the stroke displacement amount is, for example, 0 to 30 mm, the active control ratio R is fixed to 0.5 (50%), but the absolute value of the stroke displacement amount increases from 30 mm. Accordingly, the active control ratio R decreases continuously or discontinuously (the stroke damping control ratio (1-R) increases continuously or discontinuously). Further, when the absolute value of the stroke displacement increases between 30 mm and 50 mm, the decreasing slope of the active control ratio R (the increasing slope of the stroke damping control ratio (1-R)) is large, and between 50 mm and 80 mm. The decrease gradient of the active control ratio R (increase gradient of the stroke damping control ratio (1-R)) is small when increasing at. The control ratio characteristic diagram includes, at least in part, a tendency that the stroke attenuation ratio (1-R) increases with respect to the active control ratio R as the absolute value of the stroke displacement amount increases, and vice versa ( The designer can arbitrarily design so that the stroke attenuation ratio (1-R) tends to be smaller than the active control ratio R as the absolute value of the stroke displacement amount increases.

The control ratio calculation unit 56 applies the right front wheel stroke displacement amount x _sfr to the stored control ratio characteristic diagram 561, thereby obtaining the right front wheel active control ratio R _fr and the right front wheel stroke damping control ratio (1-R _fr ). Calculate. Further, the control ratio calculation unit 56 calculates the left front wheel active control ratio R _fl and the left front wheel stroke damping control ratio (1-R _fl ) by fitting the left front wheel stroke displacement amount x _sfl to the control ratio characteristic diagram 561. . Each ratio on the right front wheel side and each ratio on the left front wheel side may be calculated based on the same control ratio characteristic diagram, or may be calculated based on different control ratio characteristic diagrams.

  As described above, the control ratio calculation unit 56 increases the active control ratio R so that the stroke attenuation control ratio (1-R) increases relative to the active control ratio R as the absolute value of the stroke displacement amount increases. And the stroke damping control ratio (1-R) is calculated. The active control ratio R and the stroke damping control ratio (1-R) can be considered as gains multiplied by the active control force and the stroke damping control force, as will be described later. Therefore, the active control ratio R represents a gain related to the active control force (active control gain), and the stroke attenuation control ratio (1-R) represents a gain related to the stroke attenuation control force (stroke attenuation control gain). That is, the control ratio calculation unit 56 increases the stroke attenuation control gain relative to the active control gain as the absolute value of the stroke displacement amount of the electromagnetic shock absorber device 30, that is, the stroke displacement amount increases. Thus, the active control gain and the stroke attenuation control gain are calculated. The control ratio calculation unit 56 corresponds to the control gain calculation means of the present invention.

FIG. 12 is a functional block diagram illustrating the internal processing of the arbitration control unit 57. Arbitration control unit 57 inputs the right front wheel active control force f _bfr, this right front wheel active control force f _bfr, by multiplying the right front wheel active control ratio R _fr computed by the control ratio calculation unit 56, The corrected right front wheel active control force f _bfr * is calculated. Further, the arbitration control unit 57 inputs the right front wheel stroke damping control force f _sfr, this right front wheel stroke damping control force f _sfr, right front wheel stroke damping control ratio, which is calculated by the control ratio calculation section 56 (1 by multiplying the -R _fr), we calculate the corrected right front wheel stroke damping control force _{f sfr} *. Further, the arbitration control unit 57 calculates the corrected right front wheel ride comfort control force f _fr * by adding the calculated corrected right front wheel active control force f _bfr * and the corrected right front wheel stroke damping control force f _sfr *. Further, the arbitration control unit 57 inputs the right front wheel unsprung control force f _wfr, by adding the right front wheel unsprung control force f _wfr corrected right front riding figures comfort control force f _{fr *,} right front wheel target control force F _fr is calculated. The right front wheel target control force F _fr is a target value of the force generated by the electric motor 31 of the electromagnetic shock absorber device 30 of the right front wheel suspension body 10FR.

Further, the arbitration control unit 57 receives the left front wheel active control force f _bfl and _{multiplies the} left front wheel active control force f _bfl by the left front wheel active control ratio R _fl calculated by the control ratio calculation unit 56. To calculate the modified left front wheel active control force f _bfl *. Further, the arbitration control unit 57 inputs the left front wheel stroke damping control force f _sfl, this left front wheel stroke damping control force f _sfl, left front wheel stroke damping control ratio, which is calculated by the control ratio calculation section 56 (1 -R _fl ) is multiplied to calculate the modified left front wheel stroke damping control force f _sfl *. Further, the arbitration control unit 57 calculates the corrected left front wheel riding comfort control force f _fl * by adding the calculated corrected left front wheel active control force f _bfl * and the corrected left front wheel stroke damping control force f _sfl *. Further, the arbitration control unit 57 inputs the left front wheel unsprung control force f _WFL, by adding the left front wheel unsprung control force f _WFL corrected left riding figures comfort control force f _{fl *,} left front wheel target control force F _fl is calculated. The left front wheel target control force F _fl is a target value of the force generated by the electric motor 31 of the electromagnetic shock absorber device 30 of the left front wheel suspension body 10FL.

Thus, the arbitration control unit 57 uses the active control ratio (right front wheel active control ratio R _fr and left front wheel active control ratio R _fl ) calculated by the control ratio calculation unit 56 as the active control force (right front wheel active control force f). _The corrected active control force (right front wheel corrected active control force f _bfr * and left front wheel corrected active control force f _bfl *) calculated by multiplying _bfr and the left front wheel active control force f _bfl ) by the control ratio calculation unit 56 The calculated stroke damping control ratio (right front wheel stroke damping control ratio (1-R _fr ) and left front wheel stroke damping control ratio (1-R _fl )) is used as the stroke damping control force (right front wheel stroke damping control force f _sfr and left _Correction wheel calculated by multiplying the front wheel stroke damping control force f _sfl ) Based on the troke damping control force (modified right front wheel stroke damping control force f _sfr * and modified left front wheel stroke damping control force f _sfl *), the front wheel position of the sprung member (right front wheel position and left front wheel position) and unsprung A front wheel side target control force (right front wheel target control force F _fr and left front wheel target control force F _fl ) generated by the electric motor 31 of the electromagnetic shock absorber device 30 disposed between the members is calculated. The arbitration control unit 57 corresponds to the front wheel side target control amount calculation means of the present invention.

Further, the arbitration control unit 57 _{inputs the} right rear wheel active control force _fbrr and the right rear wheel pitch suppression control force _fprr , adds them, and further adds the input right rear wheel unsprung control force to the added value. The right rear wheel target control force F _rr is calculated by adding f _wrr . Further, the arbitration control unit 57 adds these inputs the left rear wheel active control force f _brl and left rear wheel pitch reduction control force f _prl, further the added value, the left rear wheel unsprung control force entered The left rear wheel target control force F _rl is calculated by adding f _wrl . The right rear wheel target control force _Frr is a target value of the force generated by the electric motor 31 of the electromagnetic shock absorber device 30 of the right rear wheel suspension body 10RR. The left rear wheel target control force F _rl is a target value of the force generated by the electric motor 31 of the electromagnetic shock absorber device 30 of the left rear wheel suspension body 10RL.

As described above, the arbitration control unit 57 _{calculates the} rear wheel side active control force (the right rear wheel active control force _fbrr and the left rear wheel active control force _fbrl ) and the pitch suppression control force calculation unit 54 after the calculation. based pitch reduction control force wheel side (right rear wheel pitch reduction control force f _prr and the left rear wheel pitch reduction control force f _prl), the wheel position after a sprung member (right rear wheel position and the left rear wheel position ) And the unsprung member and the rear wheel side target control force (right rear wheel target control force F _rr and left rear wheel target control force F _rl) generated by the electric motor 31 of the electromagnetic shock absorber device 30. ) Is calculated. The arbitration control unit 57 corresponds to the rear wheel side target control amount calculating means of the present invention.

The arbitration control unit 57 outputs a control signal representing each target control force F _i calculated as described above to each corresponding electric motor 31. Specifically, the arbitration control unit 57 determines a control amount (target energization amount and rotation direction of the electric motor 31) based on the target control force F _i , and the drive circuit 70 with a duty ratio corresponding to the determined control amount. A control signal is output to each switching element of each drive circuit 70 so that the switching elements open and close. Thereby, each switching element opens and closes according to the designated duty ratio. In this manner, the electric motor 31 of each electromagnetic shock absorber device 30 is driven and controlled.

According to the above embodiment, the right front wheel target control force F _fr corresponding to the target value of the driving force generated by the electric motor 31 of the electromagnetic shock absorber device 30 attached to the position of the right front wheel of the sprung member is the corrected right front wheel. The left front wheel target control force F _fl corresponding to the target value of the driving force generated by the electric motor 31 of the electromagnetic shock absorber device 30 that includes the active control force f _bfr * and is attached to the left front wheel position of the sprung member is The modified left front wheel active control force f _bfl * is included. Further, the right rear wheel target control force _Frr corresponding to the target value of the driving force generated by the electric motor 31 of the electromagnetic shock absorber device 30 attached to the position of the right rear wheel of the sprung member is the right rear wheel active control force. _fbrr is included, and the left rear wheel target control force F _rl corresponding to the target value of the driving force generated by the electric motor 31 of the electromagnetic shock absorber device 30 attached to the left rear wheel position of the sprung member is the left rear wheel. The wheel active control force _fbrl is included. Thus, since the active control force is included in the target control force for all the electromagnetic shock absorber devices 30, when the vehicle travels on the uneven road surface, the sprung member is caused by the active control element included in the target control force. The vibration of can be suppressed. That is, the sprung displacement transmission ratio is reduced.

Further, the right front wheel target control force F _fr includes a modified right front wheel stroke damping control force f _sfr *, and the left front wheel target control force F _fl includes a modified left front wheel stroke damping control force f _sfl *. Therefore, when the vehicle travels on a slope-changing road surface, the input F from the road surface is transmitted to the sprung member at an early stage as shown in FIG. 13 by the stroke damping control element included in the target control force. For this reason, the input time of the road surface input F in Formula (2) becomes longer and the peak value of the road surface input F becomes smaller. As a result, the feeling of shock is reduced.

  Further, the stroke damping control ratio (1-R) (stroke damping control gain) becomes the active control ratio R (active control gain) as the absolute value (size) of the stroke displacement amount of the electromagnetic shock absorber device 30 increases. On the other hand, it is set to be relatively large. Therefore, as the absolute value of the stroke displacement amount increases, the proportion of active control involved in the riding comfort control (active control + stroke attenuation control) decreases, and the proportion of stroke attenuation control increases. That is, the stroke attenuation control becomes dominant as the absolute value of the stroke displacement amount increases. Therefore, when the vehicle is traveling on a slope changing road surface, if the stroke displacement amount increases, the resistance force of the electromagnetic shock absorber device 30 to the expansion / contraction operation increases. Occurrence of the stopper is effectively prevented by increasing the resistance force.

Further, the right rear wheel target control force F _rr includes the right rear wheel pitch suppression control force f _prr , and the left rear wheel target control force F _rl includes the left rear wheel pitch suppression control force f _prl . These pitch suppression control forces are control amounts corresponding to the driving force that the electric motor 31 of the electromagnetic shock absorber device 30 on the rear wheel side should generate in order to suppress the movement of the sprung member around the pitch direction. . By including the control force of such a pitch direction component in the target control force, the pitch behavior of the sprung member can be suppressed.

As described above, the right front wheel target control force F _fr and the left front wheel target control force F _fl include the corrected right front wheel active control force f _bfr * and the corrected left front wheel active control force f _bfl *. Although the sprung displacement transmission ratio is reduced by the active control element, when the stroke displacement amount of the electromagnetic shock absorber device 30 is large, the correction stroke damping control element included in the target control amount becomes dominant, so the road surface input is There is a risk of transmission to the sprung member. At this time, since the pitch behavior of the sprung member is suppressed by the pitch suppression control force included in the target control force on the rear wheel side, the vibration of the sprung member in the pitch direction is suppressed. This improves ride comfort.

  Further, when the vehicle travels on the slope changing road surface, for example, as shown in FIG. 14, when the front wheel approaches the slope changing road surface, the rear wheel has not yet traveled on the slope changing road surface, but the sprung member In order to perform the pitch motion, the driving force generated by the electric motor 31 of the electromagnetic shock absorber device 30 on the rear wheel side is controlled based on the pitch suppression control force so as to suppress the pitch motion. The force for suppressing the pitch motion acts in the same direction as the direction in which the road surface input is transmitted to the sprung member. As described above, the suspension device of the present embodiment predicts the road surface on which the rear wheel side travels in advance (in terms of pre-sensing) based on the difference between the movement on the front wheel side and the movement on the rear wheel side. Based on this, a force is generated in a direction in which road surface input is transmitted to the sprung member at an early stage. For this reason, the input time of the road surface input F in Formula (2) becomes longer and the peak value of the road surface input F becomes smaller. Therefore, the shock feeling is reduced.

(Modification 1)
In the above embodiment, the active control ratio R and the stroke damping control ratio (1-R) are always calculated according to the absolute value (size) of the stroke displacement amount of the electromagnetic shock absorber device 30, and these ratios are calculated. An example is shown in which the driving force of the electric motor 31 of the electromagnetic shock absorber device 30 attached to the front wheel side of the sprung member is controlled based on the corrected active control force and the corrected stroke damping control force calculated accordingly. However, the stroke attenuation control element may be added to the control when the absolute value of the stroke displacement amount is equal to or greater than a preset threshold value. FIG. 15 is another example of the control ratio characteristic diagram. According to this control ratio characteristic diagram, when the absolute value of the stroke displacement amount of the electromagnetic shock absorber device 30 is 15 mm or less, the active control ratio R is 1 (100%), that is, the stroke damping control ratio is 0 ( 0%). Therefore, when the absolute value of the stroke displacement amount is 15 mm or less, the stroke attenuation control is not performed. On the other hand, when the absolute value of the stroke displacement amount exceeds 15 mm, the stroke attenuation control ratio (1-R) becomes a value larger than zero. That is, the stroke attenuation control is performed when the absolute value of the stroke displacement amount is larger than 15 mm. As the absolute value of the stroke displacement amount increases, the stroke attenuation control ratio (1-R) increases (the active control ratio R decreases).

  Thus, when the absolute value of the stroke displacement amount is small (in this example, 15 mm or less), the ride comfort control is executed only by the active control. Therefore, when running on an uneven road surface with many fine irregularities, the intervention of stroke damping control is prevented, and the sprung displacement transmission ratio is sufficiently reduced only by active control. Therefore, riding comfort is further improved.

(Modification 2)
In the above embodiment, the active control ratio (active control gain) R and the stroke attenuation control ratio (1-R) (stroke control gain) are determined according to the stroke displacement amount by referring to the control ratio characteristic diagram. However, any method may be adopted as long as these ratios are calculated as a result.

（３）式において、Ｃ_ｂはバネ上部材の減衰係数（正のゲイン）、Ｃ_ｗはバネ下部材の減衰係数（正のゲイン）である。Ｃ_ｂまたはＣ_ｗを可変させ、あるいはＣ_ｂおよびＣ_ｗを可変させることにより、Ｃ_ｂ＝Ｃ_ｗとなったとき、出力ｆは（４）式により表される。

FIG. 16 is a diagram illustrating a vehicle vibration model. When the vibration system shown in the figure is actively controlled by the skyhook damper theory based on the sprung vertical speed x _b ′ and the unsprung vertical speed x _w ′, the output f of the electric motor is expressed by the equation (3). .

(3) In the equation, C _b is the damping coefficient (positive gain) of the sprung member, C _w is the attenuation coefficient of the unsprung member (positive gain). When _Cb or _Cw is varied, or _Cb and _Cw are varied, and _Cb = _Cw , the output f is expressed by equation (4).

In the equation (4), x _b ′ −x _w ′ is a relative speed between the sprung member and the unsprung member (relative speed between the sprung and the unsprung part). This speed is equal to the stroke speed x _s ′ of the shock absorber device. Therefore, the output f expressed by the equation (4) is equal to the damping force expressed by multiplying the stroke speed x _s ′ of the shock absorber device by the damping coefficient. That is, when C _b = C _w , active control and stroke attenuation control are equivalent controls.

This controls based on output f in equation (3), C _b and by changing in accordance with C _w the stroke displacement amount, an active control ratio and the stroke damping control ratio of the stroke displacement magnitude It can be changed according to

ｘ_ｓｆｒ’は、ｘ_ｂｆｒ’−ｘ_ｗｆｒ’であるから、（５）式は（６）式のように変形できる。

一方、上記（３）式を用いた場合、バネ上部材の右前輪ＷＦＲに取り付けられる電磁式ショックアブソーバ装置３０の電気モータ３１についての右前輪目標制御力Ｆ_ｆｒは（７）式のように表せる。

In the above-described embodiment, the right front wheel target control force F _fr to be output by the electric motor 31 of the electromagnetic shock absorber device 30 attached to the front wheel side of the sprung member, for example, the right front wheel WFR, is expressed as in equation (5). be able to.

Since x _sfr ′ is x _bfr ′ −x _wfr ′, equation (5) can be transformed into equation (6).

On the other hand, when the above equation (3) is used, the right front wheel target control force F _fr for the electric motor 31 of the electromagnetic shock absorber device 30 attached to the right front wheel WFR of the sprung member can be expressed as the following equation (7). .

By comparing the equations (6) and (7), the equations (8) and (9) are derived.

From the equations (8) and (9), the gains C _bfr and C _wfr are gains that are changed according to the change when the active control ratio R and the stroke damping control ratio (1-R) are changed. I know that there is. Thus, depending on the stroke displacement amount, (3) by changing the gain C _b and / or gain C _w in the formula, the same effects as the above embodiment.

また、右前輪目標制御力Ｆ_ｆｒは（１１）式を用いて求められる。

(Modification 3)
In the above embodiment, the active control force is calculated by multiplying the sprung vertical speed by a gain, but the unsprung control force may be included in this active control force. In this case, since the unsprung control force can be calculated by multiplying the unsprung vertical speed by a gain, for example, the active control force F _bfr to be output by the electromagnetic shock absorber device attached to the right front wheel WFR of the sprung member is ( 10) It is calculated | required using Formula.

Further, the right front wheel target control force F _fr is obtained using equation (11).

  By using the equation (11), when the absolute value of the stroke displacement amount is small (when active control is dominant), the flat feeling of the sprung member and the grounding property of the unsprung side are improved. The shock absorber device can be controlled. On the other hand, when the absolute value of the stroke displacement is large (when the stroke damping control is dominant), the input from the road surface is effectively transmitted to the sprung member. Can do.

Further, by eliminating x _sfr ′ from the expression (11), the expression (12) is obtained.

In this case, the _relationship between the damping coefficient C _bfr of the sprung member, the active control ratio R _fr and the stroke damping control ratio (1−R _fr ) is expressed by the equation (13), and the damping coefficient C _{wfr of the} unsprung member. And the active control ratio R _fr and the stroke damping control ratio (1-R _fr ) are expressed by the following equation (14).

(Modification 4)
In the above embodiment, an example in which the pitch suppression control force is always included in the target control force for the electromagnetic shock absorber device 30 attached to the rear wheel side of the sprung member is shown in advance. If the amount of vertical displacement can be estimated, when the estimated amount of vertical displacement of the road surface, specifically, when the estimated amount of vertical displacement of the road surface exceeds the reference value, the target control force May be controlled to include a pitch suppression control force. In this case, the road surface vertical displacement amount can be estimated as follows.

（１５）式および（１６）式において、ｍ_ｂはバネ上部材の質量、ｍ_ｗはバネ下部材の質量、ｘ_ｂ”はバネ上上下加速度、ｘ_ｗ”はバネ下上下加速度、ｘ_ｂはバネ上上下変位量、ｘ_ｗはバネ下上下変位量、ｆは電気モータの出力、Ｋ_ｓはコイルスプリングのバネ定数、Ｋ_ｔはタイヤのバネ定数、ｘ_ｒは路面上下変位量である。 In the vibration system shown in FIG. 16, the equation of motion of the sprung member can be expressed by the following equation (15), and the equation of motion of the unsprung member can be expressed by the following equation (16).

In the equations (15) and (16), m _b is the mass of the sprung member, m _w is the mass of the unsprung member, x _b ″ is the sprung vertical acceleration, x _w ″ is the unsprung vertical acceleration, and x _b is sprung displacement, x _w is unsprung vertical displacement, f is the output of the electric motor, the K _s a spring constant of the coil spring, the K _t the spring constant of the tire, the x _r is a road surface vertical displacement.

また、（１５）式と（１６）式からバネ下上下変位量ｘ_ｗを消去することにより、（１８）式を得ることができる。

From Expression (15) and Expression (16), Expression (17) can be obtained.

Further, by erasing the unsprung vertical displacement _{x w} from (15) and (16), can be obtained (18).

(17) and (18) are both an expression relating the road surface vertical displacement _{x r.} Therefore, the road surface vertical displacement amount _xr can be estimated by using these equations. In the control according to this modification, when the estimated road surface vertical displacement x _r is less than the reference displacement amount set in advance after without consideration (added) pitch reduction control force (f _prr and f _prl) The target control force on the wheel side is calculated. On the other hand, when the estimated road surface vertical displacement amount exceeds the reference displacement amount, the target control force on the rear wheel side is calculated in consideration (addition) of the pitch suppression control force (f _prr and f _prl ).

  As mentioned above, although embodiment and the modification of this invention were demonstrated, this invention is not limited to these examples and should not be interpreted. For example, in the above embodiment, the maximum value of the active control ratio R is set to 0.5 (50%), but the designer can set the maximum value of the active control ratio R as appropriate. Further, according to the control ratio characteristic diagram 561 shown in FIG. 12, when the stroke displacement amount is larger than 30 mm, the active control ratio R continuously decreases as the stroke displacement amount increases. May be reduced. In the above embodiment, the active control ratio R and the stroke attenuation control ratio (1-R) are calculated, but not the control ratio but the gain related to the active control force (active control gain) and the stroke attenuation control force. Such gain (stroke attenuation control gain) may be calculated as independent gains. Even in this case, if both gains are calculated so that the stroke attenuation control gain increases relative to the active control gain as the absolute value (size) of the stroke displacement increases, The effects of the invention are achieved.

  Moreover, in the said embodiment, the aspect in the case of driving | running on this uphill road surface is illustrated especially using the uphill road surface as a gradient change road surface using FIG. 13 and FIG. However, the present invention can also be applied when traveling on a downhill road surface. When traveling on a downhill road surface only by active control, the stroke displacement amount of the electromagnetic shock absorber device on the front wheel side increases toward the expansion side as the vehicle travels on the downhill, and eventually the stopper hits at the limit position on the expansion side. The vehicle changes its traveling direction when the impact force generated by the stopper is transmitted to the sprung member.

  On the other hand, when a vehicle adopting the control method of the present invention travels on a downhill road surface (gradient changing road surface) shown in FIG. 17, a force is applied to the sprung member at an early stage by the stroke damping control element included in the target control force. F can be transmitted. For this reason, the input time of force F becomes long and the peak value of F becomes small. As a result, the feeling of shock is reduced.

  Further, as shown in FIG. 18, when the front wheel of the vehicle adopting the control method of the present invention approaches the downhill road surface, the sprung member is pitched even though the rear wheel is not yet traveling on the downhill road surface. In order to move, the driving force generated by the electric motor of the electromagnetic shock absorber device on the rear wheel side is controlled based on the pitch suppression control force so as to suppress the pitch motion. In this way, the rear wheel side predicts the traveling road surface in a presensing manner based on the pitch behavior of the vehicle, and the force is transmitted to the sprung member at an early stage based on the prediction result. It is further reduced.

In the above embodiment, the movements of the sprung member, the unsprung member, and the electromagnetic shock absorber device are detected by the sprung vertical acceleration sensor, the unsprung vertical acceleration sensor, and the stroke sensor, respectively. Motion may be estimated. For example, the motion of the sprung member can be estimated based on values detected by the unsprung vertical acceleration sensor and the stroke sensor. Moreover, it can estimate based on the value detected by one sprung vertical acceleration sensor, a pitch rate sensor, and a roll rate sensor. Further, it can be estimated from the detection value of the unsprung vertical acceleration sensor, the vehicle specifications, the control output of the control system, and the like. Moreover, in the said embodiment, although the positive / negative of the gain concerning each control force was defined, the positive / negative of a gain can be determined suitably based on the direction of a motion. For example, all the gains disclosed in the embodiments may be reversed. In addition, the active control ratio and the stroke attenuation control ratio may be obtained using the same control ratio characteristic diagram when the stroke is displaced in the extension direction and when the stroke is displaced in the contraction direction. You may obtain | require using a characteristic diagram. Thus, the present invention can be modified without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 10 ... Suspension main body, 20 ... Coil spring, 30 ... Electromagnetic shock absorber apparatus, 31 ... Electric motor, 32 ... Ball screw mechanism, 50 ... Suspension control apparatus, 51 ... State quantity calculation part, 52 ... Active control force calculation part, 53 ... stroke attenuation control force calculation unit, 54 ... pitch suppression control force calculation unit, 55 ... unsprung control force calculation unit, 56 ... control ratio calculation unit, 561 ... control ratio characteristic diagram, 57 ... arbitration control unit, 61 ... spring Upper vertical acceleration sensor, 62 ... _Unsprung vertical acceleration sensor, 63 ... Stroke sensor, 70 ... Drive circuit, f _bfr ... Right front wheel active control force,
f _bfr * ... modified right front wheel active control force, f _sfr ... right front wheel stroke damping control force, f _sfr * ... modified right front wheel stroke damping control force, f _wfr ... right front wheel unsprung control force, F _fr ... right front wheel target control Force, f _bfl ... left front wheel active control force, f _bfl * ... modified left front wheel active control force, f _sfl ... left front wheel stroke damping control force, f _sfl * ... modified left front wheel stroke damping control force, f _wfl ... left front wheel spring Lower control force, F _fl ... Left front wheel target control force, f _brr ... Right rear wheel active control force, f _prr ... Right rear wheel pitch suppression control force, f _wrr ... Right rear wheel unsprung control force, F _rr ... Right rear wheel target control force, _{f brl ...} left rear wheel active control force, _{f prl ...} left rear wheel pitch reduction control force, _{f wrl ...} left rear wheel unsprung control force, F _{rl ...} left rear wheel target control _{force, R fr} Right front active control ratio, 1-R _{fr ...} right front wheel stroke damping control ratio, R _{fl ...} left front active control ratio, 1-R _{fl ...} left front wheel stroke damping control ratio

Claims (3)

It is disposed between each wheel position of the sprung member of the vehicle and the unsprung member, and generates a driving force upon receiving energy supply so that the sprung member and the unsprung member are separated and approached. In a suspension device that includes a shock absorber device that extends and contracts and controls the expansion and contraction operation of the shock absorber device by controlling the driving force,
An active control amount calculating means for calculating an active control amount corresponding to a driving force to be generated by the shock absorber device in order to suppress the vertical motion of the sprung member based on a physical quantity related to the vertical motion of the sprung member;
A stroke attenuation control amount that calculates a stroke attenuation control amount corresponding to the driving force that the shock absorber device should generate in order to suppress the expansion / contraction operation of the shock absorber device based on a physical quantity related to the expansion / contraction operation of the shock absorber device. Computing means;
As the amount of expansion / contraction stroke displacement of the shock absorber device increases, the stroke attenuation control gain, which is the control gain related to the stroke attenuation control amount, is relatively relative to the active control gain, which is the control gain related to the active control amount. Control gain calculating means for calculating the active control gain and the stroke attenuation control gain,
The stroke attenuation control includes the corrected active control amount calculated by multiplying the active control amount by the active control gain calculated by the control gain calculating unit, and the stroke attenuation control gain calculated by the control gain calculating unit. Equivalent to the target value of the driving force generated by the shock absorber device disposed between the front wheel position of the sprung member and the unsprung member based on the corrected stroke damping control amount calculated by multiplying the amount Front wheel side target control amount calculating means for calculating the front wheel side target control amount,
A suspension device comprising: The suspension device according to claim 1,
A pitch suppression control amount calculating means for calculating a pitch suppression control amount corresponding to the driving force to be generated by the shock absorber device in order to suppress the movement of the sprung member around the pitch direction;
The shock absorber device disposed between the rear wheel position of the sprung member and the unsprung member based on the active control amount and the pitch suppression control amount calculated by the pitch suppression control amount calculation means. Rear wheel side target control amount calculating means for calculating a rear wheel side target control amount corresponding to the target value of the generated driving force;
A suspension device further comprising: The suspension device according to claim 1 or 2,
The control gain calculating means is configured such that a stroke attenuation control ratio, which is a control ratio based on the stroke attenuation control amount, is a control ratio based on the active control amount as the magnitude of the expansion / contraction stroke displacement amount of the shock absorber device increases. The suspension device, wherein the active control ratio and the stroke damping control ratio are calculated as the active control gain and the stroke damping control gain so as to increase with respect to the control ratio.

Images