Electric suspension control

Abstract

The object of the present invention is to improve traffic safety while suppressing a decrease in passenger comfort. The electric suspension control device (15) of the present invention is a control device for an electric suspension (11) having an electric motor (31), which gradually reduces the thrust command of the electric suspension under specified operating conditions and performs short-circuit control on the electric motor when the thrust command is below a specified value. Furthermore, the operating conditions are detection of an instruction to stop the power supply to the electric suspension, a short-circuit instruction in a collision countermeasure, detection of a specified vehicle speed during deceleration, or detection of a road surface change exceeding a specified value by a foresight sensor.

Description

Technical Field

[0001] The present invention relates to an electric suspension control device. Background Art

[0002] Electric suspension devices are known in the past. These are located between the vehicle body and wheels and include an electromagnetic actuator that generates a driving force related to the vibration damping of the vehicle via an electric motor (see, for example, Patent Document 1). In addition to the electric motor, the electromagnetic actuator may also include a ball screw mechanism. The electromagnetic actuator operates by converting the rotational motion of the electric motor into the linear motion of the ball screw mechanism to generate a driving force related to the vibration damping of the vehicle body. Furthermore, some electromagnetic actuators employ linear motion.

[0003] Patent Document 1 describes a suspension device that transforms the output of a high-voltage battery through a DC / DC converter and supplies power to the motor of an electric actuator. The output voltage of the DC / DC converter is corrected by subtracting a variable voltage obtained based on the power consumption indicating the operating state of the electric actuator, thereby adjusting the output voltage of the DC / DC converter so that the corrected voltage approaches a reference voltage.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-131395 Summary of the Invention

[0007] In the electric suspension having an electromagnetic actuator disclosed in Patent Document 1, if the electromagnetic actuator is switched to short-circuit control or power supply to the electromagnetic actuator is stopped, the stroke position of the electric suspension may suddenly change to a natural length, which may deteriorate passenger comfort.

[0008] The present invention has been made in view of the above circumstances and has as its object to improve traffic safety while suppressing a decrease in passenger comfort.

[0009] To solve the above problems, the electric suspension control device of the present invention is a control device for an electric suspension including an electric motor. Under predetermined operating conditions, the thrust command of the electric suspension is gradually reduced, and the electric motor is short-circuited when the thrust command is below a predetermined value.

[0010] Effects of the Invention

[0011] According to the electric suspension control device of the present invention, when the thrust output of the electric actuator is switched to short-circuit control in situations other than emergencies and errors, the thrust command is gradually reduced to perform short-circuit control, so that the stroke position of the electric suspension will not suddenly change to the natural length, and the passenger comfort will not be deteriorated. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing the overall configuration of a vehicle equipped with the electric suspension device according to the embodiment.

[0013] Figure 2 It is a partial cross-sectional view of an electromagnetic actuator included in the electric suspension device according to the embodiment.

[0014] Figure 3 It is a structural diagram of the interior and peripheral parts of the electric suspension control device according to the embodiment.

[0015] Figure 4 This is a diagram showing an example of gain adjustment in the command value adjustment unit of the electric suspension control device.

[0016] Figure 5 This is an operational flowchart of the electric suspension control device according to the embodiment.

[0017] Description of Reference Numerals

[0018] 11 Electric suspension device

[0019] 13 Electromagnetic actuator

[0020] 15ECU (Electric Suspension Control Unit)

[0021] 16 drive control lines

[0022] 31 electric motor

[0023] 40 vehicle speed sensor

[0024] 41 yaw rate sensor

[0025] 42 Foresight Sensor

[0026] 43 Information Acquisition Department

[0027] 45 Damping force calculation unit

[0028] 47 Driving force calculation unit

[0029] 48 drive unit

[0030] 49 drive control unit DETAILED DESCRIPTION

[0031] Hereinafter, an electric suspension control device (hereinafter referred to as ECU 15 ) according to an embodiment of the present invention, which switches to short-circuit control in the thrust output of an electric actuator, will be described in detail with reference to the drawings as appropriate.

[0032] In the drawings shown below, components having common functions are denoted by common reference numerals. Furthermore, the dimensions and shapes of components may be schematically shown with deformation or exaggeration for the sake of convenience.

[0033] First, refer to Figure 1 、 Figure 2 A basic configuration common to the electric suspension device 11 according to the embodiment of the present invention will be described.

[0034] Figure 1 This is a diagram showing the overall configuration common to the electric suspension device 11 according to the embodiment of the present invention. Figure 2 It is a partial cross-sectional view of the electromagnetic actuator 13 constituting a part of the electric suspension device 11 .

[0035] like Figure 1 As shown, the electric suspension device 11 according to the embodiment of the present invention comprises: a plurality of electromagnetic actuators 13 provided for each wheel of the vehicle 10; and an electronic control unit (hereinafter referred to as "ECU 15"). Between the plurality of electromagnetic actuators 13 and the ECU 15, drive signal lines 14 (see FIG. 1 ) are provided for the ECU 15 to drive the plurality of electromagnetic actuators 13. Figure 1 solid line) and the electric motor 31 from the plurality of electromagnetic actuators 13 to the ECU 15 (refer to Figure 2 ) of the rotation angle signal line 16 (refer to Figure 1 are connected to each other by dashed lines).

[0036] In this embodiment, four electromagnetic actuators 13 are provided on each of the front wheels (left front wheel, right front wheel) and the rear wheels (left rear wheel, right rear wheel). Each electromagnetic actuator 13 provided on each wheel is independently driven and controlled in coordination with the extension and retraction operation of each wheel.

[0037] In the embodiment of the present invention, the plurality of electromagnetic actuators 13 have a common configuration unless otherwise specified. Therefore, the configuration of one electromagnetic actuator 13 will be described instead of describing the plurality of electromagnetic actuators 13 .

[0038] The forward-looking sensor 42 is a CCD camera located in front of each wheel. It obtains information about the road surface ahead of the vehicle 10 based on an image of the road surface ahead of the vehicle 10. Alternatively, a laser sensor, ultrasonic sensor, or the like may be used as the forward-looking sensor 42 to obtain road surface information.

[0039] like Figure 2 As shown, the electromagnetic actuator 13 includes a base housing 17 , an outer tube 19 , a ball bearing 21 , a ball screw shaft 23 , a plurality of balls 25 , a nut 27 , and an inner tube 29 .

[0040] The base housing 17 supports the base end of the ball screw shaft 23 via a ball bearing 21, allowing it to rotate freely about its axis. The outer tube 19 is provided on the base housing 17 and houses the ball screw mechanism 18, which includes the ball screw shaft 23, a plurality of balls 25, and a nut 27. The balls 25 roll along the thread grooves of the ball screw shaft 23. The nut 27 engages with the ball screw shaft 23 via the balls 25, converting the rotational motion of the ball screw shaft 23 into linear motion. The inner tube 29, which is connected to the nut 27, is integral with the nut 27 and moves axially along the outer tube 19.

[0041] In order to transmit the rotational driving force to the ball screw shaft 23, as shown in FIG. Figure 2 As shown, the electromagnetic actuator 13 includes an electric motor 31, a pair of pulleys 33, and a belt member 35. The electric motor 31 is provided in parallel with the outer tube 19 in the base housing 17. Pulleys 33 are attached to the motor shaft 31a of the electric motor 31 and the ball screw shaft 23, respectively. The belt member 35 is wound around the pair of pulleys 33 to transmit the rotational driving force of the electric motor 31 to the ball screw shaft 23.

[0042] The electric motor 31 is provided with a resolver 37 that detects a rotation angle signal of the electric motor 31. The rotation angle signal of the electric motor 31 detected by the resolver 37 is transmitted to the ECU 15 via a rotation angle signal line 16. The electric motor 31 is rotationally driven by drive signal lines 14 connected from the ECU 15 to each of the plurality of electromagnetic actuators 13.

[0043] In addition, in this embodiment, if Figure 2 As shown, by adopting a layout in which the motor shaft 31a of the electric motor 31 and the ball screw shaft 23 are arranged substantially parallel to each other and connected to each other, the axial dimension of the electromagnetic actuator 13 can be shortened. However, a layout in which the motor shaft 31a of the electric motor 31 and the ball screw shaft 23 are arranged coaxially and connected to each other can also be adopted.

[0044] However, the structure of the electromagnetic actuator 13 in the embodiment is not limited to this, and it is of course possible to use another electromagnetic active suspension such as a linear motor type.

[0045] In the electromagnetic actuator 13 of this embodiment, Figure 2As shown, a connection portion 39 is provided at the lower end of the base housing 17. This connection portion 39 is connected and fixed to an unsprung component (not shown) (such as the wheel-side lower arm and steering knuckle). Meanwhile, the upper end 29a of the inner tube 29 is connected and fixed to an unsprung component (not shown) (such as the vehicle body-side strut tower). In short, the electromagnetic actuator 13 is arranged in parallel with an unshown spring component provided between the vehicle body and the wheel of the vehicle 10.

[0046] The electromagnetic actuator 13 constructed as described above operates as follows. For example, consider a case where a thrust force related to upward vibration is input from the wheel side of the vehicle 10 relative to the connecting portion 39. In this case, the inner tube 29 and the nut 27 want to descend as a whole relative to the outer tube 19 to which the thrust force related to upward vibration is applied. Under this influence, the ball screw shaft 23 wants to rotate in the direction in which the nut 27 descends. At this time, the electric motor 31 generates a rotational driving force in a direction that hinders the nut 27 from descending. The rotational driving force of the electric motor 31 is transmitted to the ball screw shaft 23 via the belt component 35.

[0047] In this manner, a reaction force (damping force) that opposes the thrust force associated with the upward vibration acts on the ball screw shaft 23 , thereby damping the vibration that is intended to be transmitted from the wheel side to the vehicle body side.

[0048] Next, refer to Figure 3 The configuration of the interior and peripheral portions of the ECU 15 included in the electric suspension device 11 according to the embodiment of the present invention will be described. Figure 3 It is a structural diagram of the interior and peripheral parts of the ECU 15 included in the electric suspension device 11 according to the embodiment of the present invention.

[0049] The ECU 15 is composed of a microcomputer that performs various calculations. The ECU 15 has a drive control function: by executing a program, it drives and controls each of the multiple electromagnetic actuators 13 based on the stroke position calculated from the rotation angle signal of the electric motor 31 detected by the resolver 37 and transmitted via the rotation angle signal line 16, thereby generating a driving force related to vibration damping of the vehicle body.

[0050] In order to realize such drive control functions, such as Figure 3 As shown, the ECU 15 includes an information acquiring unit 43 , a damping force calculating unit 45 , a driving force calculating unit 47 , and a driving control unit 49 .

[0051] The information acquisition unit 43 acquires the rotation angle signal of the electric motor 31 detected by the resolver 37 as time-series information on the stroke position, and acquires information on the stroke speed SV by temporally differentiating the time-series information on the stroke position.

[0052] Furthermore, the information acquisition unit 43 acquires information on the reversal of the stroke direction and information on the stroke amount AS after the reversal, which are obtained based on the time series information of the stroke position.

[0053] Moreover, if Figure 3 As shown, the information acquisition unit 43 acquires the vehicle speed detected by the vehicle speed sensor 40, the yaw rate (steering amount) detected by the yaw rate sensor 41, and the information of the upcoming road surface obtained by the anticipation sensor 42 provided on the front side of the vehicle 10.

[0054] The information of the stroke speed SV, the information of the reversal of the stroke direction, the information of the stroke amount AS after the reversal, the vehicle speed, the yaw rate, and the travel road surface acquired by the information acquisition unit 43 are sent to the damping force calculation unit 45 .

[0055] The damping force calculation unit 45 calculates a target damping force, which serves as a target value for the damping operation of the electromagnetic actuator 13, based on the information on the stroke speed SV acquired by the information acquisition unit 43. Furthermore, based on the information on the stroke amount AS after the reversal acquired by the information acquisition unit 43, the damping force calculation unit 45 corrects the target damping force, in principle, such that the smaller the stroke amount AS, the weaker the target damping force.

[0056] The corrected target damping force calculated by the damping force calculation unit 45 is sent to the driving force calculation unit 47 .

[0057] The driving force calculation unit 47 receives as input the corrected target damping force calculated by the damping force calculation unit 45 and calculates drive control information for achieving the target damping force via the electromagnetic actuator 13. The drive control information, which is the calculation result of the driving force calculation unit 47, is transmitted to the drive control unit 49 as a thrust command.

[0058] Although described in detail later, the thrust command immediately before the short-circuit control of the electromagnetic actuator 13 is referred to as a final thrust command.

[0059] The drive control unit 49 notifies the drive unit 48 that drives the electric motors 31 included in each of the plurality of electromagnetic actuators 13 of a thrust command 496 and a short-circuit command 497 in accordance with the thrust command sent from the drive force calculation unit 47 .

[0060] The drive unit 48 is supplied with driving power from a battery mounted on the vehicle 10 , and drives the electric motor 31 through the inverter circuit via the drive signal line 14 based on a thrust command 496 notified from the drive control unit 49 .

[0061] In addition, the drive unit 48 (inverter circuit) that controls the electric motor 31 switches the FETs (field effect transistors) or IGBTs (insulated gate bipolar transistors) of the drive unit 48 so that the armature coils of the electric motor 31 are electrically connected, thereby short-circuiting the drive signal line 14 and performing short-circuit control on the electromagnetic actuator 13 based on the short-circuit instruction 497 notified from the drive control unit 49. Alternatively, the drive signal line 14 may be short-circuited so that the armature coils of the electric motor 31 are connected via a resistor based on the short-circuit instruction 497 notified from the drive control unit 49. Furthermore, a relay that short-circuits the armature coils of the electric motor 31 may be provided on the drive unit 48 or the electric motor 31 side to perform short-circuit control on the electromagnetic actuator 13. In this case, the short-circuit may be performed via a resistor.

[0062] By short-circuiting the electromagnetic actuator 13, even when power is cut off, a damping force is generated based on changes in the stroke of the electromagnetic actuator 13, thereby stabilizing vehicle height vibrations while the vehicle 10 is moving. Furthermore, even when the vehicle 10 is parked, a damping force is generated based on changes in the dynamic load of the vehicle 10, thereby stabilizing vehicle height displacement.

[0063] Next, the configuration of the drive control unit 49 that processes the short-circuit command will be described.

[0064] When the electromagnetic actuator 13 is short-circuited by the setting of the action setting unit 495 described later, the command value adjustment unit 491 uses the thrust command of the driving force calculation unit 47 as the value of the final thrust command and adjusts the gain of the thrust command so that the value gradually decreases from the value of the final thrust command.

[0065] The gain of the command value adjustment unit 491 has the following characteristics: Figure 4 The characteristics of attenuation over time shown include, for example, a nonlinear attenuation reduction characteristic such as a Sigmoid function, a linear gain reduction characteristic, or a step function characteristic that decreases in steps.

[0066] The command value adjustment unit 491 sets the gain of the thrust command to Figure 4 The characteristics shown minimize the gain change between the start and end of adjustment, allowing for smooth thrust command adjustment. This prevents abrupt changes in stroke position when short-circuiting the electromagnetic actuator 13, and ensures a smooth transition to short-circuiting control, preventing degradation of passenger comfort.

[0067] The short-circuit ON / OFF determination unit 492 determines whether the thrust command value adjusted by the command value adjustment unit 491 is below a predetermined value. If the thrust command value is below the predetermined value, the short-circuit control is turned on, and a short-circuit command is output to short-circuit the electromagnetic actuator 13. The predetermined value, serving as the determination threshold, can be appropriately set to take into account changes in comfort when the electromagnetic actuator 13 transitions to short-circuit control.

[0068] The thrust command adjustment time of the command value adjustment unit 491 depends on the judgment threshold of the short-circuit ON / OFF determination unit 492 and the gain attenuation characteristics of the command value adjustment unit 491. From the perspective of suppressing changes during short-circuit control of the electromagnetic actuator 13, a smaller judgment threshold is better, but this increases the adjustment time. Therefore, a predetermined judgment threshold and adjustment time are set to determine the gain attenuation characteristics. Alternatively, the gain attenuation characteristics may be determined based on the operating conditions of the command value adjustment unit 491 and the short-circuit ON / OFF determination unit 492, described later.

[0069] The thrust command output unit 493 selects the thrust command adjusted by the command value adjustment unit 491 or the thrust command having a value of “0” as the thrust command, and notifies the drive unit 48 of the thrust command from the thrust command 496 .

[0070] The thrust command is selected based on the determination result of the short-circuit ON / OFF determination unit 492. Specifically, if the short-circuit ON / OFF determination unit 492 determines that short-circuit control is ON, a thrust command value of "0" is selected. If the short-circuit control is OFF, the thrust command adjusted by the command value adjustment unit 491 is selected and notified to the drive unit 48.

[0071] The short-circuit command output unit 494 notifies the driver unit 48 of a short-circuit command based on the ON determination result of the short-circuit ON / OFF determination unit 492, or a short-circuit command based on an emergency or error condition of the vehicle 10 detected by another ECU. Therefore, if short-circuit control is urgently required, the thrust command adjustment by the command value adjustment unit 491 is not performed, and the short-circuit command is notified to the driver unit 48, causing the driver unit 48 to immediately short-circuit the electromagnetic actuator 13. Specifically, when a short-circuit command is issued by another ECU in the event of an emergency or error condition of the vehicle 10, the driver unit 48 prioritizes short-circuit control of the electromagnetic actuator 13, disregarding any reduction in comfort (emphasis is placed on emergency braking (traffic safety) and protection against electrocution from high voltage).

[0072] Although described in detail later, the operation setting unit 495 initiates the operation of the command value adjustment unit 491 and the short-circuit ON / OFF determination unit 492 based on operational conditions such as a short-circuit command from another ECU for the electric suspension device 11. Specifically, the drive control unit 49, in the absence of a command from another ECU, notifies the drive unit 48 of the thrust command from the drive force calculation unit 47 via the thrust command 496 from the thrust command output unit 493. The short-circuit command output unit 494 does not notify the drive unit 48 of the short-circuit command 497 except in the event of an emergency or error.

[0073] The action setting unit 495 starts the action of the command value adjustment unit 491 and the short-circuit ON / OFF judgment unit 492 under any of the following action conditions: (1) when a short-circuit command is input in a countermeasure during a collision, (2) when a vehicle speed below a fixed value is detected, (3) when a power OFF command of the vehicle is input, (4) when an excessive change in the driving road surface is detected, (5) when the power supply is stopped, (6) when the electromagnetic actuator 13 does not operate normally due to a fault, etc., (7) when the ECU 15 detects an error or does not operate normally, and (8) when the capacity of the vehicle's driving power supply is reduced.

[0074] Specifically, the action condition (1) is a situation in which the electromagnetic actuator 13 is short-circuited when the high-voltage power supply to the electric suspension device 11 located outside the vehicle body is stopped as a countermeasure in the event of a collision. The action setting unit 495 starts the action of the instruction value adjustment unit 491 and the short-circuit ON / OFF judgment unit 492 based on the short-circuit instruction notified in advance by other ECUs before the power supply is stopped.

[0075] In this case, the thrust command adjustment time of the command value adjustment unit 491 is the time from notification of the short-circuit command to stop of the power supply, and is equal to or shorter than the notice time of stop of the power supply.

[0076] The electric suspension device 11 performs short-circuit control after gradually reducing the thrust of the electromagnetic actuator 13 . This prevents the stroke position of the electric suspension from suddenly changing to a natural length, thereby preventing a decrease in passenger comfort.

[0077] After the short-circuit control of the electromagnetic actuator 13 , the supply of high-voltage power to the electric suspension device 11 is stopped, thereby taking measures to prevent electric induction and the like during a collision.

[0078] Under operating condition (2), the operation setting unit 495 obtains the vehicle speed detected by the vehicle speed sensor 40 from the information acquisition unit 43. When a predetermined vehicle speed is detected during deceleration, the operation of the command value adjustment unit 491 and the short-circuit ON / OFF determination unit 492 is started. Then, if the vehicle speed further decreases, the high-voltage power supply to the electric suspension device 11 is stopped, thereby ensuring safety (preventing electric shock).

[0079] In this case, the adjustment time of the thrust command by the command value adjustment unit 491 is equal to or shorter than a predetermined deceleration time from the vehicle speed determined by the operation setting unit 495 to the vehicle speed at which the power supply is stopped.

[0080] The electric suspension device 11 gradually reduces the thrust of the electromagnetic actuator 13 and then performs short-circuit control, and then stops the power supply. This prevents the stroke position of the electric suspension device 11 from suddenly changing to a natural length, thereby preventing degradation of passenger comfort.

[0081] Under operating condition (3), the operation setting unit 495 starts the operation of the command value adjustment unit 491 and the short-circuit ON / OFF determination unit 492 in response to a vehicle power OFF command (preliminary command) from another ECU of the vehicle 10. The power supply to the electric suspension device 11 is stopped after the electromagnetic actuator 13 is short-circuited.

[0082] In this case, the thrust command adjustment time of the command value adjustment unit 491 is equal to or shorter than the time from the issuance of the power OFF command (preliminary command) by the other ECUs to the actual stop of the power supply.

[0083] By gradually reducing the thrust of the electromagnetic actuator 13 and then performing short-circuit control, the electric suspension system 11 prevents the stroke position of the electric suspension system 11 from suddenly changing to its natural length, thereby maintaining passenger comfort. Furthermore, a damping force is generated by the electromagnetic actuator 13 during short-circuit control, thereby suppressing vibrations in the vehicle 10's height caused by the power outage.

[0084] Under action condition (4), when the information of the upcoming road surface acquired by the information acquisition unit 43 from the foreseeable sensor 42 is an excessive change in the convex and concave surface that cannot be fully coped with by the electric suspension device 11, the action setting unit 495 starts the action of the instruction value adjustment unit 491 and the short-circuit ON / OFF judgment unit 492, that is, when the foreseeable sensor detects a road surface change exceeding the specified value.

[0085] The electric suspension system 11 prevents damage to the electromagnetic actuator 13 when traversing uneven surfaces by gradually reducing the thrust of the electromagnetic actuator 13 and then performing short-circuit control. Furthermore, the stroke position of the electric suspension system 11, resulting from short-circuit control of the electromagnetic actuator 13, does not abruptly change to its natural length, thereby ensuring minimum passenger comfort.

[0086] Under operating condition (5), for example, when an abnormality in the battery mounted on the vehicle 10 is detected during driving and the power supply to the electric suspension device 11 is stopped, the operation setting unit 495 starts the operation of the command value adjustment unit 491 and the short-circuit ON / OFF determination unit 492 based on a power supply stop command (preliminary command) notified from another ECU before the power supply is stopped. The power supply to the electric suspension device 11 is stopped after the electromagnetic actuator 13 is short-circuited.

[0087] In this case, the thrust command adjustment time of the command value adjustment unit 491 is equal to or shorter than the time from the issuance of the power supply stop command (preliminary command) by the other ECUs to the actual stop of the power supply.

[0088] By gradually reducing the thrust of the electromagnetic actuator 13 and then performing short-circuit control, the electric suspension system 11 prevents the stroke position of the electric suspension system 11 from suddenly changing to its natural length, thereby maintaining passenger comfort. Furthermore, a damping force is generated in the electromagnetic actuator 13 during short-circuit control, thereby suppressing vibrations in the vehicle 10 caused by a power outage.

[0089] Similarly, in operating conditions (6) to (8), the electric suspension device 11 gradually reduces the thrust of the electromagnetic actuator 13 and then performs short-circuit control. This prevents the stroke position of the electric suspension device 11 from suddenly changing to its natural length, thereby maintaining passenger comfort. Furthermore, a damping force is generated in the electromagnetic actuator 13 during short-circuit control, thereby suppressing vibrations in the vehicle 10 caused by the power supply being stopped.

[0090] The action setting unit 495 may also start the actions of the command value adjustment unit 491 and the short-circuit ON / OFF determination unit 492 based on instructions from other ECUs other than emergency and error conditions, without being limited to the above-mentioned action conditions (1) to (8).

[0091] Then, through Figure 5 The operation of the electric suspension control device according to the embodiment will be described with reference to an operation flowchart of the electric suspension control device according to the embodiment.

[0092] In step S51 (stroke position acquisition), the information acquisition unit 43 of the ECU 15 acquires the rotation angle signal of the electric motor 31 detected by the resolver 37 as time series information of the stroke position.

[0093] In step S52 (stroke speed calculation), the information acquisition unit 43 of the ECU 15 calculates the stroke speed SV by temporally differentiating the time series information of the stroke position acquired in step S51 . The information of the stroke speed SV thus calculated is sent to the damping force calculation unit 45 .

[0094] In step S53 (obtaining the stroke direction and stroke amount), the ECU 15 sequentially inputs the timing information regarding the stroke position acquired in step S51 (the rotation angle signal of the electric motor 31) at a predetermined cycle time tcl, and calculates the difference between temporally adjacent position data, i.e., the stroke difference ASD. Furthermore, based on the sign of the stroke difference ASD obtained as a result of this calculation, the ECU 15 acquires the stroke direction and the time when the stroke direction is reversed.

[0095] Next, the ECU 15 acquires information on the stroke amount AS after the reversal, starting from the reversal point RP, which is the turning point of the stroke.

[0096] In step S54 (reference damping force calculation), the damping force calculation unit 45 of the ECU 15 refers to the stroke speed SV calculated (acquired) in step S52 and the stored content of the reference damping force map 51 to obtain a reference damping force value corresponding to the stroke speed SV.

[0097] In step S55 (damping force correction ratio calculation), the damping force calculation unit 45 of the ECU 15 refers to the information obtained in step S53 when the stroke direction is reversed and the information of the stroke amount AS after the reversal, and the storage content of the damping force correction diagram 53 to calculate the damping force correction ratio RT corresponding to the stroke amount AS.

[0098] In step S56 (target damping force calculation), the damping force calculation unit 45 of the ECU 15 calculates the corrected target damping force by multiplying the value of the reference damping force calculated in step S54 by the value of the damping force correction ratio RT calculated in step S55 (in the example of this embodiment, 0.6 = < RT = < 1).

[0099] In step S57 (driving force calculation processing), the driving force calculation unit 47 of the ECU 15 obtains driving control information (thrust force command) for realizing the corrected target damping force calculated in step S56 through calculation.

[0100] In step S58, the drive control unit 49 determines whether a short-circuit instruction in an emergency or error state is detected. If detected (Yes in S58), the process proceeds to step S512; if not detected (No in S58), the process proceeds to step S59.

[0101] In step S59, the drive control unit 49 determines whether any one of the above-mentioned action conditions (1) to (5) of the action setting unit 495 is satisfied. If satisfied (yes in S59), it proceeds to step S511; if not satisfied (no in S59), it proceeds to step S510.

[0102] In step S510, the drive control unit 49 notifies the drive unit 48 of the drive control information (thrust command) obtained in step S57, and sets the thrust of the electromagnetic actuator 13. Then, the process returns to step S51 in order to periodically perform the processes of steps S51 to S510.

[0103] In step S511, the drive control unit 49 adjusts the drive control information (thrust command) obtained in step S57 so that it gradually decreases. The adjusted thrust command is then sequentially notified to the drive unit 48, thereby gradually decreasing the thrust of the electromagnetic actuator 13. If the thrust command is adjusted to a value below a predetermined value, the process proceeds to step S512.

[0104] In step S512 , the drive control unit 49 notifies the drive unit 48 of a short-circuit command to perform short-circuit control on the electromagnetic actuator 13 , and then ends the process.

[0105] According to the electric suspension control device (ECU15) of the embodiment, in situations other than emergencies and errors, when the thrust output of the electric actuator is switched to short-circuit control, the thrust of the electromagnetic actuator 13 is adjusted in a manner that gradually decreases. When the thrust of the electromagnetic actuator 13 is adjusted to below the specified value, short-circuit control is performed, so that the stroke position of the electric suspension device 11 will not suddenly change to the natural length, and the passenger comfort will not be deteriorated.

[0106] In the above description, the electromagnetic actuator 13 is described as a high-voltage component. However, high-voltage components such as in-wheel motors, air conditioners, travel motors, and electric stabilizers can also be controlled in the same manner.

[0107] The present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the gist of the invention.

Claims

1. An electric suspension control device comprising an electric motor, wherein: The thrust command of the electric suspension is gradually reduced in response to a short-circuit control command as a countermeasure in the event of a collision, and the electric motor is short-circuited when the thrust command is equal to or less than a predetermined value. After the short-circuit control, the power supply to the electric suspension is stopped.

2. An electric suspension control device comprising an electric motor, wherein: The thrust command of the electric suspension is gradually reduced according to a predetermined vehicle speed detected during deceleration, and the electric motor is short-circuited when the thrust command is below a predetermined value. When the vehicle speed becomes lower, the power supply to the electric suspension is stopped.

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