JP5921223B2 - Suspension control device - Google Patents

Description

  The present invention relates to a suspension control device that is mounted on a vehicle such as a four-wheeled vehicle and is preferably used for controlling the posture of a vehicle body.

  In general, an air suspension control device mounted on a vehicle discharges air springs provided on, for example, left and right front wheels and left and right rear wheels from a vehicle-mounted air compressor (air compressor). By expanding and contracting using compressed air, the vehicle height is appropriately adjusted in accordance with changes in vehicle weight, driver preferences, and the like. A suspension control device combining an air suspension and a motor-driven active suspension has also been proposed (see, for example, Patent Document 1).

  In addition, the target roll angle is obtained from the lateral acceleration when the vehicle is running, the target pitch angle is calculated according to the target roll angle, and the difference between the actual roll angle and the actual pitch angle is obtained to perform feedback control. A vehicle damping force control device that realizes a behavior is also known (see, for example, Patent Document 2). Further, there has been known one that proposes a method of correcting the tilt in the left-right direction from a state where the vehicle body is tilted obliquely by a hydraulic suspension (see, for example, Patent Document 3).

  On the other hand, various studies have been made so far regarding feeling during vehicle steering (for example, see Non-Patent Documents 1, 2, and 3). Non-Patent Document 1 focuses on the relationship between the roll angle and the pitch angle when the vehicle travels, and when the phase difference between the roll angle and the pitch angle is small, the feeling of vehicle riding comfort, steering stability, etc. is good. It is described. Non-Patent Document 2 describes that the feeling is good in the case of a roll behavior with a head-down pitching during steering. Further, Non-Patent Document 3 describes that the feeling is good when the rotation shaft has a small shake when the roll behavior of the vehicle body and the pitch behavior are combined.

The contents described in these non-patent documents 1 to 3 can be roughly classified into two as shown in the following (1) and (2).
(1). Small phase difference between roll angle and pitch angle (2). Roll behavior with head-down pitch

JP 2008-155758 A Japanese Patent No. 4155299 JP 2008-120360 A

Hideki Sakai and 5 others, “Improvement of roll feeling based on visual sensitivity”, Toyota Technical Review Vol. 55 No. 1 (NoV 2006), pp. 20-24 Kawagoe Kenji, “Suspension Technology for Improving Roll Feel”, Automotive Technology Vol. 51 No. 11 (1997), pp. 20-24 Kazushi Fukuba and two others, “Car Body Posture Measurement Technology Using GPS”, Mazda Technical Report No. 20 (2002), pp. 130-138

  By the way, in the prior art, none of the behaviors (1) and (2) is realized by using an air suspension during a turning operation by steering a vehicle. In the prior art described in Patent Document 1, vehicle height adjustment by an air suspension is prohibited during a turning operation of the vehicle. Further, in the semi-active suspension, it is possible to control the roll rate and the pitch rate, but it is not possible to directly control the vehicle body posture such as the pitch angle and the roll angle.

  In the air suspension, the vehicle height of each wheel can be changed, and the pitch angle and roll angle can be controlled. However, when the vehicle height is raised by filling the air spring (air spring) with compressed air using an air compressor, the vehicle height changes at a low speed, so the vehicle can be used in a short time such as when turning. It cannot cope with changes in posture.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is, for example, a suspension control apparatus that can improve both ride comfort, feeling and stability when a vehicle turns. Is to provide.

In order to solve the above-mentioned problem, the invention of claim 1 is a suspension control device for controlling the posture of the vehicle body having a suspension that adjusts the vehicle height by fluid between each wheel of the vehicle and the vehicle body. A warp stiffness calculating means for obtaining a target warp stiffness which is a rotational stiffness in a diagonal direction of the vehicle body according to a lateral jerk of the vehicle body, and changing the warp stiffness of the vehicle body to be the target warp stiffness. A warp stiffness changing means, wherein the warp stiffness changing means changes the vehicle height by allowing the fluid to flow between suspensions of a front turning outer wheel and a rear turning inner wheel among the wheels of the vehicle. Thus, the warp rigidity is changed, and the vehicle posture of the front lowering roll is realized by utilizing the inertia force of the vehicle at the time of turning .

  As described above, according to the present invention, the warp rigidity of the vehicle body is reduced in accordance with the lateral jerk of the vehicle, so that the roll and the pitch are generated simultaneously by the inertial force at the time of turning, and the vehicle posture of the front lowering roll can be realized. It becomes.

It is a circuit block diagram which shows the suspension control apparatus by the 1st Embodiment of this invention. It is a flowchart which shows the air suspension control process by the controller in FIG. FIG. 3 is a flowchart specifically illustrating a pitch-roll control process in FIG. 2. FIG. FIG. 4 is a control block diagram illustrating a process of calculating the supply / discharge valve opening on each wheel side from the lateral acceleration of the vehicle model by the controller in FIG. 1, showing the contents of the supply / discharge valve opening command calculation in FIG. 3. It is a whole block diagram which shows the flow of the air through the supply / discharge valve between the air suspensions of each wheel side. It is a top view which shows typically the turning running state of a vehicle. FIG. 6 is a characteristic diagram showing a relationship among a steering angle, a lateral acceleration, a roll angle, a pitch angle, a lateral jerk, and a supply / discharge valve opening during turning. It is a circuit block diagram which shows the suspension control apparatus by 2nd Embodiment. FIG. 9 is a control block diagram illustrating a process of calculating a supply / discharge valve opening and a tank valve opening on each front wheel side from a lateral acceleration of the vehicle model by the controller in FIG. 8. It is a whole block diagram which shows the flow of the air between each air suspension and air tank of a front wheel side. It is a circuit block diagram which shows the suspension control apparatus by 3rd Embodiment. FIG. 6 is a characteristic diagram showing the relationship among steering angle, lateral acceleration, roll angle, pitch angle, lateral jerk, feed valve opening, roll rate, left front wheel side and right rear wheel side damping force characteristics during turning.

  Hereinafter, a suspension control device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example the case of mounting on a vehicle such as a four-wheeled vehicle.

  Here, FIG. 1 to FIG. 7 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes an in-vehicle compressor unit. The compressor unit 1 includes an air compressor 2, an electric motor 3, a suction filter 4, a part of a supply / exhaust conduit 5, an air dryer 6, a slow return valve 7, and an exhaust, which will be described later. The valve 8 and the exhaust pipe 9 are included.

  Reference numeral 2 denotes an air compressor serving as an air pressure source. The air compressor 2 is constituted by, for example, a reciprocating compressor or a scroll compressor, and is mounted on the rear side of a vehicle body (not shown), for example. Has become the main part of. The air compressor 2 is driven by an electric motor 3 as a drive source, and compresses the outside air or the air sucked from the suction filter 4 side to generate compressed air (hereinafter referred to as air). The suction filter 4 also functions as a silencer that reduces suction noise.

  Reference numeral 5 denotes an air supply / exhaust pipe connected to the discharge side of the air compressor 2, and one side (base end side) of the supply / exhaust pipe 5 is as shown in FIG. The other side (front end side) extends to the outside of the compressor unit 1. Connection points 5 </ b> A and 5 </ b> B to which branch pipes 12 </ b> A to 12 </ b> D (described later) are connected are provided on the distal end side of the supply / discharge pipe 5.

  Reference numeral 6 denotes an air dryer as an air drying means provided in the middle of the supply / exhaust pipe 5. The air dryer 6 incorporates, for example, a moisture adsorbent (not shown) and the like, and a slow return valve 7 and a later-described valve. Between the exhaust pipe 9 and the exhaust pipe 9. The slow return valve 7 is configured by a parallel circuit of a throttle 7A and a check valve 7B, and the check valve 7B is not opened and the air flow rate is not throttled for a forward flow described later. However, the check valve 7B closes against the flow in the reverse direction, and the flow of the air at this time is throttled by the throttle 7A, so that the air flows slowly in the air dryer 6 at a small flow rate.

  When the high-pressure air generated in the air compressor 2 circulates in the forward direction toward the pneumatic equipment (air suspensions 10A to 10D described later), the air dryer 6 contacts the air adsorbent with the air. Thus, moisture is adsorbed and dried air is supplied toward air springs 11A to 11D described later. On the other hand, when the air (exhaust gas) discharged from the air springs 11A to 11D flows in the air dryer 6 in the reverse direction, the dried air flows back through the air dryer 6, so that the moisture adsorbent in the air dryer 6 is dried. Moisture is desorbed by air. Thereby, the moisture adsorbent is regenerated and returned to a state where moisture can be adsorbed again.

  Reference numeral 8 denotes an exhaust valve connected to the supply / exhaust pipe line 5 through an exhaust pipe line 9. The exhaust valve 8 is configured by using an electromagnetic valve as an exhaust solenoid valve, and is normally closed and the exhaust pipe line is closed. 9 is blocked from the exhaust port 9A. When the exhaust valve 8 is excited by energization from the outside (a controller 18 described later), the exhaust valve 8 is opened to connect the exhaust pipe 9 to the exhaust port 9A, and the air in the supply / exhaust pipe 5 is in the atmosphere. Is discharged (released).

  10A and 10B indicate left and right (FL, FR) air suspensions provided on the front wheel side of the vehicle, and 10C and 10D indicate left and right (RL, RR) air suspensions provided on the rear wheel side of the vehicle. Is shown. Here, the air suspensions 10A to 10D are provided with air springs 11A, 11B, 11C, and 11D, respectively, positioned between the vehicle wheel side and the vehicle body side (both not shown).

  When these air springs 11A to 11D supply or discharge air through branch pipes 12A to 12D and supply / discharge valves 13A to 13D, which will be described later, the supply / discharge amount (air amount) at this time is reduced. Correspondingly, it expands and contracts downward. Thus, the air springs 11A to 11D individually adjust the vehicle height on the front wheel side and the rear wheel side of the vehicle together with the air suspensions 10A to 10D, and the vehicle height is raised and lowered for each wheel.

  Reference numerals 12A, 12B, 12C, and 12D are branch pipes, and these branch pipes 12A to 12D are connected from the supply / discharge pipe 5 to connect the air springs 11A to 11D to the supply / discharge pipe 5 individually. They are branched from each other at the points 5A and 5B. That is, the branch pipes 12A and 12B are connected to the supply / discharge pipe 5 at the connection point 5A, and the branch pipes 12C and 12D are connected to the supply / discharge pipe 5 at the connection point 5B.

  Reference numerals 13A, 13B, 13C, and 13D are supply / discharge valves including solenoid valves provided for the branch pipes 12A to 12D. These supply / discharge valves 13A to 13D are normally closed to air as shown in FIG. The springs 11 </ b> A to 11 </ b> D are blocked from the supply / exhaust pipe 5. When the supply / discharge valves 13A to 13D are excited by energization from the outside (a controller 18 which will be described later), the valves are individually opened independently. When the valves are opened, the air springs 11A to 11D are connected to the supply / discharge pipes. It communicates with the road 5 individually.

  Here, an air dryer 6 is provided in the middle of the supply / exhaust pipeline 5 between the exhaust valve 8 and the slow return valve 7 to dry the air. For this reason, this air can be dried by the air dryer 6 before supplying the air from the air compressor 2 to the air springs 11 </ b> A to 11 </ b> D via the supply / exhaust pipeline 5, the branch pipelines 12 </ b> A to 12 </ b> D, and the like. . As a result, the air in the air springs 11A to 11D can be kept in a dry state, moisture can be prevented from remaining in the air springs 11A to 11D, and a vehicle using the air springs 11A to 11D can be prevented. The high adjustment operation can be performed smoothly and stably, and the ride comfort and comfort of the vehicle can be enhanced.

  The left front wheel (FL) side air suspension 10A is provided with a front left vehicle height sensor 14A, and the right front wheel (FR) side air suspension 10B is provided with a front right vehicle height sensor 14B. The left rear wheel (RL) side air suspension 10C is provided with a rear left vehicle height sensor 14C, and the left rear wheel (RR) side air suspension 10D is provided with a rear right vehicle height sensor 14D.

  On the vehicle body side, a vehicle speed sensor 15 for detecting a traveling speed, a steering angle sensor 16 for detecting a steering angle of a handle (not shown), a vehicle height change switch 17 and the like are provided. The vehicle height change switch 17 is operated, for example, when the vehicle height is appropriately raised or lowered according to the operator's preference or the like.

  Reference numeral 18 denotes a controller as a control device configured by a microcomputer or the like. The controller 18 has a front left vehicle height sensor 14A, a front right vehicle height sensor 14B, a rear left vehicle height sensor 14C, Connected to the right vehicle height sensor 14D, the vehicle speed sensor 15, the steering angle sensor 16, the vehicle height change switch 17, and the like, and the output side of the controller 18 is connected to the electric motor 3, the exhaust valve 8, the supply / discharge valves 13A to 13D, and the like. ing.

  Here, the controller 18 has a storage unit 18A composed of, for example, a ROM, a RAM, a non-volatile memory, and the like. In this storage unit 18A, for example, a program for air suspension control processing shown in FIG. 2, shown in FIG. A program for pitch-roll control processing and the like are stored. Further, as shown in FIG. 4, the controller 18 includes a vehicle model unit 19, a differentiation unit 20, an absolute value calculation unit 21, a front wheel side gain multiplication unit 22, a rear wheel side gain multiplication unit 23, and a front and rear wheel side turn. The direction determination units 24 and 25 are included.

  In this case, based on the vehicle speed signal detected by the vehicle speed sensor 15 and the steering angle signal detected by the steering angle sensor 16, the controller 18 estimates and calculates the lateral acceleration in the vehicle model unit 19 as described below. Then, based on the estimated lateral acceleration and the lateral jerk described later, the opening degree of the supply / discharge valves 13A to 13D is calculated by feedforward control (FF control) as described later, so that the feeling and stability during turning of the vehicle are calculated. And can improve.

First, the vehicle model unit 19 estimates the lateral acceleration αy by using the vehicle model of the following equation 1 from the steering angle (front wheel steering angle δf) and the vehicle speed V. Here, the lateral acceleration αy can be obtained by the equation (1) when the linear model of the vehicle is assumed and the dynamic characteristics are ignored. Where V is the vehicle speed (m / s), A is the stability factor (S ² / m ² ), δf is the front wheel steering angle (rad), and L is the wheel base (m).

  Next, the differentiation unit 20 differentiates the lateral acceleration to calculate the lateral jerk, and the absolute value calculation unit 21 obtains the absolute value | u | of the lateral jerk. The next-stage front wheel gain multiplying unit 22 multiplies the absolute value | u | of the lateral jerk by the Fr gain for the front wheels. Further, the rear wheel gain multiplying unit 23 multiplies the absolute value | u | of the lateral jerk by the Rr gain for the rear wheel. Here, the front wheel side gain multiplying unit 22 and the rear wheel side gain multiplying unit 23 together with the turning direction determining units 24 and 25, the target warp rigidity which is the rotational rigidity in the diagonal direction of the vehicle body according to the lateral jerk of the vehicle body. The warp stiffness calculation means for obtaining the above is configured.

  The front and rear wheel turning direction determination units 24 and 25 determine the turning direction of the vehicle based on the steering angle signal detected by the steering angle sensor 16. When it is determined that the vehicle is turning right, an opening degree command is output from the controller 18 to the supply / discharge valve 13A on the left front wheel (FL) side and the supply / discharge valve 13D on the right rear wheel (RR) side. In this case, the supply / discharge valves 13A and 13D change the warp stiffness of the vehicle body to the target warp stiffness by communicating the air springs 11A and 11D between the air suspensions 10A and 10D on the FL and RR sides. The warp stiffness changing means is configured.

  When the turning direction determination units 24 and 25 determine that the vehicle is turning left, the controller 18 outputs an opening degree command to the supply / discharge valve 13B on the right front wheel (FR) side and the supply / discharge valve 13C on the left rear wheel (RL) side. . In this case, the supply / discharge valves 13B and 13C change the warp stiffness of the vehicle body to the target warp stiffness by communicating the air springs 11B and 11C between the air suspensions 10B and 10C on the FR and RL sides. The warp stiffness changing means is configured.

  The suspension control apparatus according to the present embodiment has the above-described configuration. Next, air suspension control processing including vehicle height adjustment processing by the controller 18 will be described with reference to FIG.

  In step 1 in FIG. 2, it is determined based on a detection signal from the steering angle sensor 16 whether or not the vehicle is turning. Here, when sudden steering such as during danger avoidance is detected, it is determined that the vehicle is not turning. When it is determined “NO” in step 1, the process proceeds to the next step 2 to determine whether or not there is a request for vehicle height adjustment. While it is determined as “NO” in step 2, the vehicle is not turning, and it is not necessary to adjust the vehicle height. Therefore, the control proceeds to the next step 3 to maintain the air amount.

  That is, in this case, the driving of the air compressor 2 by the electric motor 3 is stopped, the exhaust valve 8 is kept closed, and the exhaust pipe 9 is shut off from the exhaust port 9A. As a result, the air flow in the supply / exhaust conduit 5 is stopped, and the air suspensions 10A to 10D on the respective wheel sides are held by the air springs 11A to 11D without changing the vehicle height.

  On the other hand, when “YES” is determined in step 2, a command for adjusting the vehicle height is issued, so the process proceeds to step 4 to determine whether or not the actual vehicle height is lower than the target vehicle height. While it is determined as “NO” in step 4, the actual vehicle height is higher than the target vehicle height, so the process proceeds to step 5 to perform the process of discharging air. That is, when it is determined that the vehicle height is high in the air suspensions 10A to 10D on the respective wheels, the supply / discharge valves 13A to 13D are excited and opened, the exhaust valve 8 is opened, and the air springs 11A to 11A are opened. The air is discharged from 11D to the outside of the exhaust port 9A through the supply / discharge conduit 5 and the exhaust conduit 9.

  Thereby, on each wheel side, the air springs 11A to 11D of the air suspensions 10A to 10D are reduced as the air is discharged, and the vehicle height is adjusted to be lowered at the positions of all four wheels. Note that the vehicle height adjustment work in such a lowering direction is not necessarily performed on all four wheels. Control may be performed to independently reduce or stop the air springs 11A to 11D of the air suspensions 10A to 10D on each wheel side in accordance with the vehicle height signals output from the vehicle height sensors 14A to 14D.

  On the other hand, if “YES” is determined in step 4, the actual vehicle height is lower than the target vehicle height, so that the process proceeds to step 6 to supply air. That is, when it is determined that the vehicle height is low in the air suspensions 10A to 10D on the respective wheels, the air compressor 2 is driven by the electric motor 3 to generate high-pressure air, and the supply / discharge valves 13A to 13D are turned on. Energize to open the valve. Thereby, the air generated from the air compressor 2 is supplied from the connection points 5A and 5B of the supply / exhaust pipeline 5 into the air springs 11A to 11D of the air suspensions 10A to 10D via the branch pipelines 12A to 12D. Is done.

  Thereby, on each wheel side, the air springs 11A to 11D of the air suspensions 10A to 10D are extended or expanded as the air is supplied, and the vehicle height is adjusted in the raising direction at the positions of all four wheels. In addition, it is not always necessary to carry out the vehicle height adjustment work in such a raising direction, and the air springs 11A to 11D of the air suspensions 10A to 10D are individually extended and stopped independently on each wheel side. Control may be performed.

  On the other hand, when “YES” is determined in Step 1, the vehicle is turning. Therefore, the process proceeds to the next Step 7 and “Pitch-Roll Control” is performed as processing from Steps 11 to 15 shown in FIG. This “pitch-roll control” is a process performed to improve both the ride comfort, feeling and running stability of the operator during a turning operation of the vehicle.

  That is, when the “pitch-roll control” shown in FIG. 3 is started, the compression operation of the air compressor 2 is stopped in step 11, and the exhaust valve 8 is kept closed in the next step 12. Next, in this state, the opening degree command for any of the supply / discharge valves 13A to 13D is calculated by the process of step 13.

  Specifically, the lateral jerk is obtained by differentiating the lateral acceleration estimated and calculated by the vehicle model unit 19 of the controller 18 shown in FIG. Then, the absolute value | u | of the lateral jerk is multiplied by the front wheel Fr gain by the front wheel side gain multiplier 22 to obtain opening commands for the front wheel side supply / discharge valves 13A and 13B. Further, the rear wheel side gain multiplier 23 multiplies the absolute value | u | of the lateral jerk by the Rr gain for the rear wheel to obtain an opening degree command for the supply / discharge valves 13C and 13D on the rear wheel side. The turning direction determination units 24 and 25 determine the turning direction of the vehicle.

  In the next step 14, it is determined whether or not the opening / closing processing of the supply / discharge valves 13A to 13D has been completed for all four wheels. While it is determined as “NO” in step 14, the process proceeds to step 15, and any of the supply / discharge valves 13 </ b> A to 13 </ b> D is opened and closed based on the opening degree command. If "YES" is determined in step 14, all opening / closing valve commands for the four supply / discharge valves 13A to 13D are output, and the open / close valves 13A to 13D are opened / closed for all four wheels. Since the valve processing is completed, the “pitch-roll control” processing is terminated.

  In this case, the opening degree of the supply / discharge valves 13A to 13D can be adjusted by the driving current if the valve uses a proportional solenoid. Further, in the case of a valve that cannot achieve the intermediate opening, the on-off valve time can be adjusted by controlling the pulse width by PWM control, for example.

  Next, a case where the traveling vehicle 100 is turned to the right will be described as an example with reference to FIGS. As shown in FIG. 6, when the vehicle 100 reaches the corner portion of the road 26 and turns in the right direction, the steering operation is performed in the order of straight ahead → transient turn → steady turn → transient turn → straight forward. At this time, the driver of the vehicle 100 operates the steering wheel so as to switch the steering angle along the characteristic line 27 in FIG.

  When the vehicle 100 travels straight, the steering angle becomes substantially zero and is kept neutral. When the vehicle reaches a transitional turn from time t1 to t2, the steering angle is increased by a necessary angle. When a steady turn from time t2 to t3 is reached, the steering angle is maintained at a substantially constant angle so as to maintain the required angle. Thereafter, when a transient turn from time t3 to t4 is reached, an operation to return the steering angle to neutral is performed. When the vehicle returns to straight running after time t4, the steering angle becomes substantially zero and is kept neutral.

  The lateral acceleration generated in the turning vehicle 100 changes corresponding to the steering angle characteristic line 27 as shown by the characteristic line 28 in FIG. 7, and increases or decreases so as to be substantially proportional. The roll angle of the vehicle 100 that is turning also changes corresponding to the steering angle characteristic line 27 and the lateral acceleration characteristic line 28 as shown by the characteristic line 29 in FIG. .

  Characteristic lines 30 and 31 in FIG. 7 indicate characteristics of the pitch angle and lateral jerk of the vehicle 100 that is turning. Among these, the lateral jerk characteristic line 31 is shown as a characteristic obtained by differentiating the lateral acceleration characteristic line 28. The lateral jerk of the vehicle 100 that is turning is a rising curve like the characteristic line portion 31A at the time of a transient turn from time t1 to t2, and returns to a substantially zero equilibrium state at a steady turn from time t2 to t3. Thereafter, when a transitional turn at time t3 to t4 is reached, a falling curve is formed as shown by the characteristic line portion 31B, and after time t4, the state returns to an almost zero equilibrium state again.

  A characteristic line 32 in FIG. 7 indicates a characteristic when the supply / discharge valves 13A and 13D are controlled to be opened and closed based on the characteristic line 31 of the lateral jerk. That is, from the controller 18, when the vehicle 100 turns to the right, a left front wheel (FL) side supply / discharge valve 13A that becomes a turning outer wheel on the front wheel side and a right rear wheel (RR) side that becomes a turning inner wheel on the rear wheel side. An opening degree command is output to the supply / discharge valve 13D. The other supply / discharge valves 13B and 13C are kept closed. Therefore, the supply / discharge valves 13A and 13D are controlled to open like the characteristic line portion 32A from time t1 to time t2 (transient turning) from the closed state, and when time t2 to time t3 (steady turning) is reached. The valve is closed. Thereafter, valve opening control is performed as in the characteristic line portion 32B at time t3 to t4 (during transient turning), and the valve is again closed after time t4.

  When the vehicle 100 shown in FIG. 5 starts to turn right from the straight traveling state, the supply / discharge valve 13A on the left front wheel (FL) side and the supply / discharge valve 13D on the right rear wheel (RR) side are controlled to open. As a result, the air spring 11A on the left front wheel side and the air spring 11D on the right rear wheel side are in communication with each other. At this time, in the vehicle 100 that is turning right, the air in the air spring 11A on the front turning outer wheel (ie, the left front wheel) side is changed to the turning inner wheel on the rear wheel side (ie, the right rear wheel). It flows in the direction of arrow A in FIG. 5 toward the air spring 11D on the side. As a result, the vehicle 100 can realize the vehicle posture of the front lowering roll.

  During the subsequent steady turning, all the supply / discharge valves 13A to 13D are kept closed, so that the posture of the vehicle 100 is maintained in a stable state. During a transient turn before the turn is completed (time t3 to t4 in FIG. 7), the left front wheel side supply / discharge valve 13A and the right rear wheel side supply / discharge valve 13D are opened again, and the left front wheel side air spring 11A is opened. And the right rear wheel side air spring 11D communicate with each other. Then, due to the inertial force of the vehicle 100, the air in the air spring 11D on the right rear wheel side returns to the air spring 11A on the left front wheel side in the direction indicated by the arrow B in FIG.

  In addition, the amount of air in the air springs 11A to 11D immediately after the turn may not be the same as before the turn due to the change in the load balance before and after the vehicle due to the load capacity of the vehicle and the number of passengers and the influence of the road surface. . However, in the first embodiment, when the air suspension control process shown in FIG. 2 determines “NO” in step 1, that is, when it is determined that the vehicle is not turning, the vehicle height adjustment is performed in the control process after step 2. For this reason, even if the amount of air in the air springs 11A to 11D immediately after turning is not the same as before turning, the vehicle height adjustment in a desired state is automatically realized by the vehicle height adjustment control performed after turning. be able to.

  Thus, according to the first embodiment, as shown in FIG. 4, the controller 18 includes the vehicle model unit 19, the differentiation unit 20, the absolute value calculation unit 21, the front wheel side gain multiplication unit 22, the rear wheel side gain multiplication. It has the structure which has the part 23 and the turning direction determination parts 24 and 25 by the side of a front and a rear wheel. The front wheel side gain multiplying unit 22 and the rear wheel side gain multiplying unit 23 include a warp stiffness calculating means for obtaining a target warp stiffness that is a rotational stiffness in a diagonal direction of the vehicle body according to a lateral jerk of the vehicle body, and a turning direction determining unit. 24 and 25 together.

  When the front and rear wheel side turning direction determination units 24 and 25 determine that the vehicle is turning right, for example, the controller 18 sends an opening command to the left front wheel side supply / discharge valve 13A and the right rear wheel side supply / discharge valve 13D. Is output. The supply / discharge valves 13A and 13D connect the air springs 11A and 11D to each other between the air suspensions 10A and 10D on the left front wheel and right rear wheel sides, so that the warp rigidity of the vehicle body becomes the target warp rigidity. The warp rigidity changing means for changing is configured.

  That is, the present inventors reduce the rotational rigidity in the diagonal direction of the vehicle in accordance with the lateral jerk of the vehicle in order to realize the vehicle posture of the forward-lowering roll with little phase difference between the pitch and the roll when the vehicle turns. I came to realize that it should be done. More specifically, in the air suspensions 10A to 10D of the four-wheel vehicle, the rotational rigidity in the diagonal direction of the vehicle 100 is filled in the air springs 11A and 11D (or air springs 11B and 11C) of the diagonal wheels. Determined by the amount of air. By controlling the opening and closing of the supply / discharge valves 13A to 13D without using the compressor unit 1 (the air compressor 2, the exhaust valve 8, etc.), the air in the air spring 11A or 11B of the front wheel of the turning outer wheel is discharged. It is determined that it is sufficient that the air is discharged at the beginning of the turn and supplied to return the air into the air spring at the end of the turn.

  According to the first embodiment, the warp rigidity of the vehicle body decreases according to the lateral jerk of the vehicle by the configuration as described above, so that the roll and the pitch are simultaneously generated by the inertial force at the time of turning, and the front lowering roll The vehicle posture can be realized. That is, the warp rigidity changing means is configured to change the vehicle height by the air springs 11A to 11D of the air suspensions 10A to 10D generated by the fluid (air). In particular, the warp rigidity is changed by allowing air to flow between the air suspensions 10A and 10D (or between the air suspensions 10B and 10C) of the turning outer wheel of the front wheel and the turning inner wheel of the rear wheel among the wheels of the vehicle. It is configured.

  Thus, the vehicle posture can be adjusted using the inertial force of the vehicle at the time of turning only by performing the opening / closing control of the supply / discharge valves 13A to 13D that block and communicate the air flow. For this reason, the air suspensions 10A to 10D can cope with steep changes in the vehicle posture during turning. In addition, warp rigidity is ensured during steady turning or straight travel where no lateral jerk is generated, and the vehicle body posture of the vehicle can be maintained. On the other hand, at the time of sudden steering, the air suspensions 10A to 10D can be operated in the same manner as in the prior art. For this reason, the warp rigidity of the vehicle body does not change during sudden steering, and the stability of the vehicle body can be ensured during a sudden turn such as avoiding danger.

  Next, FIGS. 8 to 10 show a second embodiment of the present invention. A feature of the present embodiment is that the warp rigidity of the vehicle body is changed by allowing fluid (air) to flow between the air suspension of the front turning outer wheel of each wheel of the vehicle and the pressure storage tank. It is to have done. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 41 denotes an air tank as a pressure storage tank provided on the discharge side of the compressor unit 1. The air tank 41 is connected in the middle of the supply / exhaust pipe line 5 via a tank pipe 42. That is, the proximal end side of the tank pipe 42 is connected to the supply / exhaust conduit 5 at a position between the compressor unit 1 (specifically, the slow return valve 7) and the connection point 5A, and the distal end side is an air tank. 41 is connected to the supply / discharge port 41A.

  43 is a tank valve comprising an electromagnetic valve provided in the tank pipe 42, and the tank valve 43 is normally closed to shut off the air tank 41 from the supply / discharge line 5 as shown in FIG. 8. When the tank valve 43 is excited by energization from the outside (a controller 44 described later), the tank valve 43 is opened, and the inside of the air tank 41 is communicated with the supply / discharge line 5. For this reason, the air pressure in the air tank 41 is set to a pressure equal to that in the supply / discharge line 5 when the tank valve 43 is opened.

  Reference numeral 44 denotes a controller as a control device employed in the second embodiment. The controller 44 is configured in substantially the same manner as the controller 18 described in the first embodiment, and its input side is the front left vehicle height sensor 14A. The front right vehicle height sensor 14B, the rear left vehicle height sensor 14C, the rear right vehicle height sensor 14D, the vehicle speed sensor 15, the steering angle sensor 16, and the vehicle height change switch 17 are connected. However, the output side of the controller 44 is different from that of the first embodiment in that it is connected to the tank valve 43 in addition to the electric motor 3, the exhaust valve 8, and the supply / discharge valves 13A to 13D.

  Here, the controller 44 has a storage unit 44A composed of, for example, a ROM, a RAM, a non-volatile memory, and the like, and the storage unit 44A is similar to the storage unit 18A described in the first embodiment. 2 stores a program for air suspension control processing shown in FIG. 2, a program for pitch-roll control processing shown in FIG. As shown in FIG. 9, the controller 44 includes a vehicle model unit 19, a differentiation unit 20, an absolute value calculation unit 21, a front wheel side gain multiplication unit 22, and a front wheel side turning direction determination unit 24. .

  However, the controller 44 in this case is different from the controller 18 described in the first embodiment in that a tank valve gain multiplication unit 45 is provided. The tank valve gain multiplication unit 45 multiplies the absolute value | u | of the lateral jerk by the tank valve gain. Here, the front wheel gain multiplying unit 22 and the tank valve gain multiplying unit 45 constitute a warp stiffness calculating means for obtaining a target warp stiffness that is the rotational stiffness in the diagonal direction of the vehicle body in accordance with the lateral jerk of the vehicle body. Yes.

  When the turning direction determination unit 24 on the front wheel side determines that the vehicle is turning right, an opening degree command is output from the controller 44 to the supply / discharge valve 13A and the tank valve 43 on the left front wheel (FL) side. In this case, the supply / discharge valve 13A and the tank valve 43 communicate the FL side air suspension 10A (air spring 11A) and the air tank 41 with each other, thereby increasing the warp rigidity of the vehicle body to the target warp rigidity. A warp stiffness changing means for changing is configured.

  When the front wheel turning direction determination unit 24 determines that the vehicle is turning left, the controller 44 outputs an opening degree command to the supply / discharge valve 13B and the tank valve 43 on the right front wheel (FR) side. In this case, the supply / discharge valve 13B and the tank valve 43 allow the FR-side air suspension 10B (air spring 11B) and the air tank 41 to communicate with each other, thereby increasing the warp rigidity of the vehicle body to the target warp rigidity. A warp stiffness changing means for changing is configured.

  In the pitch-roll control process according to the second embodiment, either one of the supply / discharge valves 13A and 13B on the front wheel side is opened according to the turning direction of the vehicle, and the tank valve 43 is also opened at this time. . However, the supply / discharge valves 13C and 13D on the rear wheel side are held in the closed state during the pitch-roll control process.

  Thus, also in the second embodiment configured as described above, the vehicle height can be adjusted for each wheel by executing the air suspension control process shown in FIG. 2 by the controller 44, and the pitch shown in FIG. By executing the roll control process, it is possible to improve both the feeling and stability at the time of turning of the vehicle, as in the first embodiment.

  In particular, in the second embodiment, the air spring 11A or 11B of the air suspension 10A or 10B, which becomes the turning outer wheel on the front wheel side when the vehicle 100 turns, is configured to communicate with or shut off from the air tank 41. For example, when the vehicle 100 shown in FIG. 10 starts turning right from a straight traveling state and when the vehicle 100 finishes turning, both the supply / discharge valve 13A and the tank valve 43 on the left front wheel side are opened. The air spring 11A on the left front wheel side and the air tank 41 are communicated with each other.

  For this reason, at the beginning of turning of the vehicle 100, air flows in the direction of arrow C in FIG. 10 from the air spring 11A on the left front wheel side toward the air tank 41 due to the inertial force accompanying the turning operation. As a result, the vehicle 100 can realize the vehicle posture of the front lowering roll. During the subsequent steady turn (time t2 to t3 illustrated in FIG. 7), all the supply / discharge valves 13A to 13D and the tank valve 43 are kept closed, so that the posture of the vehicle 100 is maintained in a stable state. The

  Further, at the time of transitional turning before the vehicle 100 finishes turning (time t3 to t4 illustrated in FIG. 7), the supply / discharge valve 13A and the tank valve 43 on the left front wheel side are opened again. Thereby, the air spring 11A on the left front wheel side and the air tank 41 are in communication with each other. Then, due to the inertial force of the vehicle 100, the air in the air 41 returns to the air spring 11A on the left front wheel side in the direction indicated by the arrow D in FIG.

  For example, when the vehicle height is adjusted before the vehicle travels or when it is determined “NO” (ie, not turning) in step 1 by the air suspension control process illustrated in FIG. When the vehicle height is adjusted, the tank valve 43 is temporarily opened, so that the air pressure in the air tank 41 is equal to the pressure in the supply / exhaust conduit 5 (that is, the pressure equal to that in the air springs 11A to 11D). Is set.

  Next, FIG. 11 and FIG. 12 show a third embodiment of the present invention. A feature of this embodiment is that the warp rigidity of the vehicle body is changed using an air suspension device capable of adjusting the damping force characteristic. Note that in the third embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  In the figure, reference numerals 50A and 50B denote semi-active dampers formed of left and right (FL, FR) air suspensions provided on the front wheel side of the vehicle. Reference numerals 50C and 50D denote semi-active dampers formed of left and right (RL, RR) air suspensions provided on the rear wheel side of the vehicle. Here, the air springs 51A, 51B, 51C, and 51D are provided in the semi-active dampers 50A to 50D in the same manner as the air suspensions 10A to 10D described in the first embodiment.

  However, the semi-active dampers 50 </ b> A to 50 </ b> D are provided with damping force adjustment valves 52 </ b> A to 52 </ b> D as damping force adjusting means, and the damping force characteristics are variably adjusted according to a control signal output from the controller 53 described later. The damping force characteristics of the semi-active dampers 50A to 50D are adjusted continuously or stepwise between soft characteristics and hard characteristics by the damping force adjusting valves 52A to 52D.

  53 is a controller as a control device adopted in the third embodiment. The controller 53 is configured in substantially the same manner as the controller 18 described in the first embodiment, and the input side thereof is the front left vehicle height sensor 14A. The front right vehicle height sensor 14B, the rear left vehicle height sensor 14C, the rear right vehicle height sensor 14D, the vehicle speed sensor 15, the steering angle sensor 16, and the vehicle height change switch 17 are connected. However, the output side of the controller 53 is different from that of the first embodiment in that it is connected to the damping force adjustment valves 52A to 52D in addition to the electric motor 3, the exhaust valve 8 and the supply / discharge valves 13A to 13D. ing.

  Here, the controller 53 has a storage unit 53A composed of, for example, a ROM, a RAM, a non-volatile memory, and the like, and the storage unit 53A is substantially the same as the storage unit 18A described in the first embodiment. 2 stores a program for air suspension control processing shown in FIG. 2, a program for pitch-roll control processing shown in FIG. In addition, the controller 53 calculates a damping force command proportional to the lateral jerk or vertical speed of the vehicle body and the roll rate so as to reduce the posture change when the vehicle turns, and the damping force command signal (control signal) is used as a semi-active damper. Output to the damping force adjustment valves 52A to 52D of 50A to 50D.

  In this case, the vertical speed of the vehicle body can be calculated by calculating the change in the vehicle height as the vertical speed by differentiating the vehicle height signals detected by the vehicle height sensors 14A to 14D. Further, the roll rate on the vehicle body side can be detected using a roll rate sensor. Further, a method may be employed in which the roll rate is obtained from the angular velocity calculated geometrically by obtaining the respective vertical speeds on the left and right wheel sides of the vehicle body.

  Next, as an example, the vehicle 100 (see FIG. 6) reaches the corner portion of the road 26 and turns rightward (straight forward → transient turn → steady turn → transient turn → straight forward). The operation of the suspension control device will be described. At this time, the driver of the vehicle 100 operates the steering wheel so as to switch the steering angle along the characteristic line 27 in FIG.

  Further, the lateral acceleration and lateral jerk also change in the same manner as the characteristic lines 28 and 31 illustrated in FIG. The characteristic line 32 when opening and closing the supply / discharge valves 13A and 13D on the FL and RR sides also has the same characteristics as in the first embodiment.

  On the other hand, the roll angle of the vehicle that is turning is changed as indicated by a characteristic line 54 in FIG. 12, and the pitch angle is changed as indicated by a characteristic line 55. That is, the roll angle and the pitch angle of the vehicle change corresponding to the steering angle characteristic line 27 and the lateral acceleration characteristic line 28, and increase or decrease so as to be substantially proportional. However, since the change in posture during turning of the vehicle is reduced by the semi-active dampers 50A to 50D, the roll angle characteristic line 54 and the pitch angle characteristic line 55 are the characteristics of FIG. 7 described in the first embodiment. It is kept smaller than the lines 29 and 30.

  Further, the roll rate also changes as shown by the characteristic line 56 in FIG. 12, becomes a rising curve like the characteristic line part 56A at the time of the transient turning at the time t1 to t2, and becomes almost zero when the steady turning at the time t2 to t3. Return to the equilibrium state. Thereafter, when a transient turn at time t3 to t4 is reached, a falling curve is formed as shown by characteristic line portion 56B, and after time t4, the state returns to an almost zero equilibrium state again.

  A characteristic line 57 in FIG. 12 indicates a damping force characteristic by the semi-active damper 50A on the left front wheel (FL) side. The semi-active damper 50A on the left front wheel (FL) side, which is the outer turning wheel on the front wheel side, is attenuated so as to have a hard characteristic on the contraction side like the characteristic line portion 57A at the time t1 to t2 (at the time of transient turning) at the initial turning. When the force is adjusted and time t2 to t3 (steady turn) is reached, the soft characteristics are restored. After that, at times t3 to t4 (during transient turning), the damping force is adjusted so as to have a hard characteristic on the extension side like the characteristic line portion 57B, and after time t4, control is performed so as to return to the soft characteristic again. .

  A characteristic line 58 in FIG. 12 indicates a damping force characteristic by the semi-active damper 50D on the right rear wheel (RR) side. The semi-active damper 50D on the right rear wheel (RR) side, which is the inner turning wheel on the rear wheel side, has a hard characteristic on the expansion side like the characteristic line portion 58A at the time t1 to t2 (at the time of transient turning) at the initial stage of turning. When the damping force is adjusted to time t2 to t3 (steady turn), the soft characteristics are restored. After that, at time t3 to t4 (during transient turning), the damping force is adjusted so as to be hard on the contraction side like the characteristic line portion 58B, and after time t4, control is performed so as to return to the soft characteristic again. .

  Thus, also in the third embodiment configured as described above, the vehicle height can be adjusted for each wheel by executing the air suspension control processing shown in FIG. By executing the roll control process, it is possible to improve both the feeling and stability at the time of turning of the vehicle, as in the first embodiment.

  In particular, in the third embodiment, a damper that is attached between each wheel side and the vehicle body and applies a damping force to reduce the vibration of the vehicle body is a semi-active damper provided with damping force adjustment valves 52A to 52D. 50A to 50D, and the damping force generated by the semi-active dampers 50A to 50D is variably adjusted according to a control signal from the controller 53.

  Supply and discharge valves for the left front wheel (FL) and the right rear wheel (RR) at times t1 to t2 (when transient turning is started) and when the vehicle is finished turning t3 to t4 (when transient turning is started) 13A and 13D open, and the air springs 11A and 11D on the left front wheel side and the right rear wheel side communicate with each other. By reducing the rigidity in the roll direction and the pitch direction about the right front wheel and the left rear wheel, the air in the air spring 11A on the left front wheel side is air spring 11D on the right rear wheel at the beginning of turning due to the inertia of the vehicle. It can flow in and roll forward.

  Moreover, at this time, the semi-active dampers 50A to 50D can generate a damping force proportional to the roll rate, and the roll rate and the pitch rate are reduced by adding the damping force in the roll direction and the pitch direction. be able to. For this reason, as in the first embodiment, it is possible to realize the vehicle posture of the front lowering roll, and it is possible to suppress a sudden posture change.

  In the third embodiment, among the air springs 51A to 51D of the semi-active dampers 50A to 50D provided on each wheel side, when the vehicle turns, the turning outer wheel on the front wheel side and the turning inner wheel on the rear wheel side The case where the air springs communicate with each other has been described as an example. However, the present invention is not limited to this. For example, the air tank 41 described in the second embodiment may be used so that the air tank 41 communicates with the inside of the air spring serving as the turning outer wheel on the front wheel side.

  Moreover, in each said embodiment, the case where the air compressor 2 was comprised by the reciprocating compressor or the scroll compressor was mentioned as an example, and was demonstrated. However, the present invention is not limited to this. For example, a vane type or trochoid type air compressor may be used.

  Next, the invention included in the above embodiment will be described. According to the present invention, the warp rigidity changing means changes the vehicle height of each front wheel of the vehicle body. In particular, when the suspension is provided between each wheel of the vehicle and the vehicle body, the warp stiffness changing means is configured to change the vehicle height of the suspension by adjusting the flow of fluid.

  Thereby, for example, the vehicle posture can be adjusted using the inertial force of the vehicle at the time of turning only by opening / closing control of a valve that blocks and communicates fluid such as high-pressure air. For this reason, the air suspension can cope with a steep change in the vehicle posture during turning. In addition, warp rigidity is ensured during steady turning or straight travel where no lateral jerk is generated, and the vehicle body posture of the vehicle can be maintained.

  Further, the warp stiffness changing means is configured to change the warp stiffness by allowing the fluid to flow between suspensions of a front turning outer wheel and a rear turning inner wheel among the wheels of the vehicle. Even in this case, the same effects as those described above can be obtained.

  Further, the warp stiffness changing means is configured to change the warp stiffness by allowing the fluid to flow between a suspension of a front turning outer wheel and a pressure storage tank among the wheels of the vehicle. Even in this case, the same effects as those described above can be obtained.

1 Compressor unit 2 Air compressor 3 Electric motor (drive source)
4 Suction Filter 5 Supply / Exhaust Pipe Line 6 Air Dryer 7 Slow Return Valve 8 Exhaust Valve 9 Exhaust Pipe Line 10A-10D Air Suspension (Suspension)
11A to 11D, 51A to 51D Air spring 12A to 12D Branch pipe 13A to 13D Supply / exhaust valve (warp rigidity changing means)
14A-14D Vehicle height sensor 18, 44, 53 Controller (control device)
22 Front wheel gain multiplication section (warp stiffness calculation means)
23 Rear wheel side gain multiplier (warp stiffness calculation means)
24, 25 Turning direction determination unit (warp stiffness calculation means)
26 Road 41 Air tank (pressure storage tank)
43 Tank valve (warp stiffness changing means)
45 Tank valve gain multiplier (warp stiffness calculation means)
50A ~ 50D Semi-active damper (suspension)
52A to 52D Damping force adjusting valve (Damping force adjusting means)
100 vehicles

Claims (4)

A suspension control device for controlling a posture of a vehicle body of the vehicle having a suspension for adjusting a vehicle height by a fluid between each wheel and the vehicle body of the vehicle,
Warp stiffness calculating means for obtaining a target warp stiffness that is a rotational stiffness in a diagonal direction of the vehicle body according to a lateral jerk of the vehicle body;
Warp stiffness changing means for changing the warp stiffness of the vehicle body to be the target warp stiffness;
The warp rigidity changing means changes the warp rigidity by allowing the fluid to flow between suspensions of a front turning outer wheel and a rear turning inner wheel among the wheels of the vehicle. A suspension control device that realizes a vehicle posture of a front lowering roll by using an inertia force of a vehicle . Between the suspensions, fluid can flow through a pipe line and a supply / discharge valve, and by controlling the opening / closing of the supply / discharge valve, the vehicle height of each suspension is changed and the warp rigidity is changed. The suspension control device according to claim 1. A suspension control device for controlling a posture of a vehicle body of the vehicle having a suspension for adjusting a vehicle height by a fluid between each wheel and the vehicle body of the vehicle,
Warp stiffness calculating means for obtaining a target warp stiffness that is a rotational stiffness in a diagonal direction of the vehicle body according to a lateral jerk of the vehicle body;
Warp stiffness changing means for changing the warp stiffness of the vehicle body to be the target warp stiffness;
Wherein the warp stiffness changing means may change the warp stiffness by allowing flow through the fluid between the suspension and the pressure storage tank front turning outer wheel of each wheel of the vehicle, the cornering A suspension control device that realizes a vehicle posture of a front lowering roll by using an inertia force of a vehicle . The suspension, the suspension control apparatus according to any one of claims 1 to 3, wherein the adjustable der Rukoto damping force characteristics.

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