Seat control device

Abstract

The present disclosure appropriately controls the attitude of a seat on which an occupant of a vehicle is seated when the vehicle is braked. A seat control device controls driving of an actuator that can change the attitude of a seat on which an occupant of a vehicle is seated, and controls the attitude of the seat when the vehicle is braked, wherein, in a case where it is determined that a sink behavior in which a front portion of the seat moves downward from a position before braking occurs at the start of braking of the vehicle, first control is performed in which a force opposite in direction to a pitch angular velocity of the seat is output from the actuator, and in a case where it is determined that a swing-back behavior in which the front portion of the seat moves upward from the position before braking occurs from after the first control is performed until the vehicle stops, second control is performed in which a force identical in direction to the pitch angular velocity of the seat is output from the actuator.

Description

Technical Field

[0001] This invention relates to a seat control device. Background Technology

[0002] Patent Document 1 discloses a seat control device for controlling the posture of a vehicle occupant's seat. This seat control device controls an actuator capable of rotating the seat in the pitch, yaw, and roll directions. In the configuration described in Patent Document 1, when the vehicle body tilts forward or backward due to sudden deceleration or acceleration, the actuator is activated based on a pitch rate sensor reading to rotate the seat in the pitch direction, thereby maintaining the seat cushion horizontally.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-090181 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] When a vehicle brakes, the pitch vibrations that occur in the seat in response to the vehicle's swaying can be exemplified by the sinking motion that occurs at the start of braking and the swaying motion that occurs until the vehicle comes to a stop. However, in the configuration described in Patent Document 1, it is possible that the sinking and swaying motions of the seat that occur during vehicle braking cannot be accurately detected, and the seat posture cannot be properly controlled from the start of braking until the vehicle comes to a stop, thereby deteriorating ride comfort.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a seat control device that can properly control the posture of the seat in which the occupants of a vehicle are seated when the vehicle is braking.

[0009] Means for solving technical problems

[0010] The seat control device of the present invention controls the drive of an actuator capable of changing the posture of a seat in which a vehicle occupant sits, and controls the posture of the seat when the vehicle is braking. Specifically, if it is determined that a downward movement occurs in the front part of the seat relative to its pre-braking position when braking begins, a first control is executed, in which the actuator outputs a force opposite to the pitch angular velocity direction of the seat. If it is determined that a upward movement occurs in the front part of the seat relative to its pre-braking position from the execution of the first control until the vehicle stops, a second control is executed, in which the actuator outputs a force in the same direction as the pitch angular velocity direction of the seat.

[0011] According to this configuration, the seat posture can be appropriately controlled from the start of vehicle braking until the vehicle comes to a stop. In particular, by executing a second control from the execution of the first control until the vehicle comes to a stop, it is possible to suppress the occupant's upper body from moving away from the seat. As a result, ride comfort is improved.

[0012] Alternatively, the situation in which the sinking action is determined to have occurred can be either a situation where the rate of change of the pitch angular velocity of the seat is greater than or equal to a specified value, or a situation where the rate of change of the brake pedal force is greater than or equal to a threshold value.

[0013] Based on this configuration, the seat sinking action that occurs immediately after braking can be accurately detected.

[0014] Alternatively, the situation in which the swinging action is determined to occur can be when the brake pedal force is smaller than when the braking begins, and the forward and backward acceleration acting on the seat is in a constant direction and has decreased.

[0015] Based on this configuration, the swing motion that occurs from the execution of the first control until the vehicle stops can be accurately detected.

[0016] Alternatively, the first control may be executed if it is determined that the front of the seat has moved downward relative to its position before braking from the time the second control is executed until the vehicle stops.

[0017] Based on this configuration, it is possible to accurately detect the pitch vibration of the seat from the execution of the second control until the vehicle stops.

[0018] Alternatively, multiple seats may be provided on the vehicle, and the actuator may be provided for each of the multiple seats, performing the first control and the second control for each of the multiple seats.

[0019] According to this configuration, first control and second control can be performed for each of the multiple seats installed in the vehicle.

[0020] Alternatively, multiple seats may be provided on the floor of the vehicle, and the actuator may be configured to move the entire floor in the pitch direction of the vehicle, thereby performing the first control and the second control in such a manner that the entire floor moves in the pitch direction of the vehicle.

[0021] According to this configuration, the posture of multiple seats installed in the vehicle can be changed by moving the entire floor of the vehicle in the pitch direction.

[0022] Invention Effects

[0023] According to the present invention, the posture of the seat can be appropriately controlled from the start of vehicle braking until the vehicle comes to a stop. In particular, by executing a second control from the execution of the first control until the vehicle comes to a stop, it is possible to suppress the movement of the occupant's upper body away from the seat. As a result, riding comfort is improved. Attached Figure Description

[0024] Figure 1 This is a diagram showing a vehicle equipped with the seat control device described in the embodiment.

[0025] Figure 2 It is a three-dimensional diagram used to illustrate the seat and actuator.

[0026] Figure 3 This is a block diagram used to illustrate the seat control device.

[0027] Figure 4 This is a flowchart illustrating the seat control process.

[0028] Figure 5 It is a timing diagram showing the control state and seat movement during braking.

[0029] Figure 6 This is a diagram showing a modified example of a vehicle equipped with a seat control device. Detailed Implementation

[0030] The seat control device according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0031] Figure 1 This diagram shows a vehicle equipped with the seat control device described in the embodiment. The seat control device 1 controls the posture of the seat 2 installed in the vehicle Ve. The vehicle Ve is equipped with the seat control device 1. This seat control device 1 is configured to control the posture of the seat 2 to an appropriate posture in response to the swaying of the vehicle Ve that occurs when the vehicle Ve brakes.

[0032] Seat 2 is installed on the floor of vehicle Ve for the occupants of vehicle Ve to sit on. Vehicle Ve has multiple seats 2, including a driver's seat, a front passenger seat, and rear seats. Figure 2 As shown, seat 2 includes: a seat cushion 2a with a seat surface, a seat back 2b supporting the back of the occupant, and a footrest 2c for placing the occupant's feet. When the vehicle Ve is in motion and the seat cushion 2a moves in the pitch direction, the seat back 2b and footrest 2c move in the pitch direction together with the seat cushion 2a. Furthermore, seat 2 changes its posture by being driven by actuator 3.

[0033] Actuator 3 is a drive device capable of changing the posture of seat 2. Actuator 3 is configured to rotate seat 2 in the pitch direction of vehicle Ve.

[0034] like Figure 2 As shown, actuator 3 enables seat 2 to rotate about three axes: pitch, yaw, and roll. For example, actuator 3 includes a first actuator that rotates seat 2 in the pitch direction, a second actuator that rotates seat 2 in the yaw direction, and a third actuator that rotates seat 2 in the roll direction. Driven by actuator 3, seat 2 can change its attitude in the pitch, yaw, and roll directions. Furthermore, actuator 3 is controlled and driven by seat control device 1.

[0035] Figure 3 This is a block diagram used to illustrate the seat control device.

[0036] The seat control unit 1 is an electronic control device for controlling the vehicle Ve. This electronic control device is configured to include a microcontroller with a CPU, RAM, ROM, and input / output interfaces. The seat control unit 1 processes signals according to a program pre-stored in the ROM. The seat control unit 1 receives signals from various sensors mounted on the vehicle Ve.

[0037] Examples of signals input to the seat control unit 1 include signals from the vehicle speed sensor 21, the acceleration sensor 22, the brake stroke sensor 23, the master cylinder pressure sensor 24, and the seat angular velocity sensor 25. The vehicle Ve includes: a vehicle speed sensor 21 for detecting vehicle speed; an acceleration sensor 22 for detecting the fore-and-aft acceleration of the seat 2; a brake stroke sensor 23 for detecting the amount of brake pedal depressed; a master cylinder pressure sensor 24 for detecting brake pedal force; and a seat angular velocity sensor 25 for detecting the angular velocity of the seat 2 in the pitch direction (hereinafter referred to as pitch angular velocity). The vehicle speed sensor 21 outputs a vehicle speed signal. The acceleration sensor 22 outputs a seat fore-and-aft acceleration signal (seat fore-and-aft G-signal). The brake stroke sensor 23 outputs a brake signal. The master cylinder pressure sensor 24 outputs a master cylinder pressure signal. The seat angular velocity sensor 25 outputs a seat angular velocity signal. The seat control unit 1 then performs various controls based on the signals input from the various sensors.

[0038] For example, the seat control device 1 performs seat control to control the posture of the seat 2 when the vehicle is under Ve braking. In this case, the seat control device 1 uses a signal input from the brake stroke sensor 23 to detect the depressing of the brake pedal and performs seat control. The seat control device 1 includes a control unit 11 that performs seat control. The seat control includes a first control that causes the actuator 3 to output a force opposite to the direction of the pitch angular velocity of the seat 2, and a second control that causes the actuator 3 to output a force in the same direction as the pitch angular velocity of the seat 2. The control unit 11 controls the actuation of the actuator 3 so that the seat 2 is in an appropriate posture when the vehicle is under Ve braking. At this time, the control unit 11 uses the first control and the second control respectively depending on the situation.

[0039] In this way, the seat control device 1 appropriately changes the posture of the seat 2 according to the amount of brake pedal depressing, thereby suppressing the pitch vibration of the occupant seated on the seat 2. At this time, the seat control device 1 considers not only the initial braking at the moment of emergency braking, but also the swaying of the vehicle Ve that occurs after braking begins and until the vehicle comes to a stop, and performs seat control accordingly. Seat control includes control of the downward movement of the seat 2 at the start of braking, and control of the subsequent swaying movement. That is, a scenario in which seat control is performed can be exemplified by the driver depressing the brake pedal while the vehicle Ve is in motion, causing the vehicle Ve to decelerate and come to a stop. In this scenario, the seat control device 1 controls the posture of the seat 2 by controlling the drive of the actuator 3, so that the occupant is separated from the swaying of the vehicle Ve caused by the swaying during emergency braking, thus suppressing the pitch vibration of the occupant.

[0040] In detail, during emergency braking, the front of the vehicle Ve initially drops downwards immediately after braking begins. The pitch vibration generated on the seat 2 at this time becomes the first angular velocity of the first wave caused by this drop. The direction of the first angular velocity is the direction of rotation of the front of the seat 2 as it moves downwards relative to its pre-braking position. During emergency braking, as the vehicle Ve drops, the seat 2 also drops. Therefore, when the rate of change of the pitch angular velocity of the seat 2 is large, the seat control device 1 uses the actuator 3 to apply a force opposite in phase to the first angular velocity, suppressing the drop of the seat 2 and thus suppressing the occupant's movement caused by the drop. In this case, the control unit 11 performs the first control in the seat control.

[0041] Furthermore, before the vehicle Ve comes to a stop, a sway phenomenon occurs due to the forward and backward acceleration. Therefore, a swaying motion occurs on seat 2 due to the forward and backward acceleration. The pitch-direction vibration generated on seat 2 becomes the second angular velocity of the second wave of the sway. The direction of the second angular velocity is the direction of rotation in which the front of seat 2 moves upward relative to its pre-braking position. That is, the second angular velocity acts in the opposite direction to the first angular velocity. Furthermore, when the forward and backward acceleration acting on seat 2 is constant (rearward direction) due to braking, and the pitch angular velocity of seat 2 is pushed from front to back due to the second angular velocity, the occupant's upper body will be in a state of leaving the seat back 2b. To suppress this situation, when the seat control device 1 determines that a swaying motion of seat 2 has occurred, it uses actuator 3 to apply a force with the same phase as the second angular velocity to control the posture of seat 2. By outputting a force with the same phase as the second angular velocity from the actuator 3, the front part of the seat 2 can be moved upward compared to its position before braking, causing the seat 2 to tilt backward in the direction that presses the upper body of the occupant sitting on the seat cushion 2a towards the seat back 2b. This suppresses forward movement of the occupant's upper body, stabilizing the occupant's upper body on the seat back 2b side. In this case, the control unit 11 performs the second control in the seat control.

[0042] Following this, the pitch-direction vibration generated on seat 2 can be represented by a third triangular velocity, which is the third wave of the swing. The direction of the third angular velocity is the direction of rotation in which the front of seat 2 moves downward relative to its position before braking. Seat control device 1 controls the posture of seat 2 to be in the opposite phase to the third triangular velocity of the swing vibration, suppressing the swaying of seat 2 and effectively suppressing vibration to the occupant. In this case, control unit 11 performs the first control in seat control.

[0043] Thus, when the vehicle is braking (Ve), at the beginning of braking when the pitch velocity of seat 2 is high, an opposite phase is applied to suppress the sinking of seat 2. Then, when the vibration caused by braking converges to a certain degree, the same phase is applied to stabilize the occupant's upper body. Finally, when the occupant's upper body has stabilized, an opposite phase is applied again to suppress the swaying of seat 2.

[0044] Furthermore, since multiple seats 2 are provided on the vehicle Ve, the seat control device 1 is configured to perform seat control on each seat 2. That is, the seat control device 1 controls the drive of each actuator 3 provided on the seat 2. Therefore, the control unit 11 performs first control and second control on each seat 2.

[0045] Figure 4 This is a flowchart illustrating the seat control process. Figure 4The process shown is repeatedly executed by the control unit 11 of the seat control device 1 while the vehicle Ve is in motion.

[0046] During the movement of vehicle Ve, control unit 11 acquires vehicle information (step S1). In step S1, as vehicle information, vehicle speed, braking signal, master cylinder pressure, seat angular velocity, and front-rear acceleration are acquired. Vehicle speed is the current vehicle speed obtained from the signal from vehicle speed sensor 21. Braking signal is obtained from the signal from brake stroke sensor 23, indicating that the brake is closed when the driver has not pressed the brake pedal, and that the brake is open when the driver has pressed the brake pedal. Master cylinder pressure is obtained from the signal from master cylinder pressure sensor 24, indicating the magnitude of the brake pedal force. Seat angular velocity is obtained from the signal from seat angular velocity sensor 25, indicating the pitch angular velocity of seat 2. Front-rear acceleration is obtained from the signal from acceleration sensor 22, indicating the front-rear acceleration acting on seat 2. In step S1, the front-rear acceleration of seat 2 is detected as a representative value of the unsprung front-rear acceleration and sprung front-rear acceleration of vehicle Ve. Thus, in step S1, in addition to detecting the seat angular velocity through the seat angular velocity sensor 25 and the forward and backward acceleration through the acceleration sensor 22, the control unit 11 also linearly detects the brake pedal force through the master cylinder pressure sensor 24.

[0047] The control unit 11 determines whether the brake is engaged (step S2). In step S2, it determines whether the brake pedal is depressed based on the signal from the brake stroke sensor 23. In step S2, it uses the brake signal obtained in step S1 to determine whether the brake has switched from being deactivated to being engaged, or whether the brake is engaged continuously.

[0048] If it is determined that the brake is not engaged (step S2: "No"), the control routine ends.

[0049] When the brakes are determined to be engaged (step S2: "Yes"), the control unit 11 calculates the deviation σ between the target value A and the actual seat angular velocity, which is the pitch angular velocity of the seat 2 (step S3). In step S3, using the seat angular velocity (actual seat acceleration) obtained in step S1 and the preset target value A, the deviation σ is obtained by subtracting the actual seat acceleration from the target value A. The target value A is set to zero, representing the case where the seat 2 is in its basic posture, that is, the case where the seat cushion 2a is in a horizontal state. The basic posture refers to the posture of the seat 2 before braking or the posture of the seat 2 in a stopped state. For example, the basic posture is when the seat cushion 2a is held in a horizontal posture. Therefore, the deviation σ is a value representing how much the posture of the seat 2 deviates from the basic posture in the pitch direction.

[0050] Furthermore, since the pitch angular velocity of seat 2 has a rotational direction, one direction is set as positive and the other as negative regarding the seat angular velocity. In this description, the seat angular velocity is set to positive when the front part of seat 2 moves downward relative to the basic posture, and negative when the front part of seat 2 moves upward relative to the basic posture. In other words, when the front part of seat cushion 2a moves downward relative to its pre-braking position due to the downward movement of seat 2 during braking, the seat angular velocity is positive. After that, when the front part of seat cushion 2a moves upward relative to its pre-braking position due to the swinging movement of seat 2, the seat angular velocity is negative. Therefore, the deviation σ calculated in step S3 is either positive or negative. When the front part of seat 2 moves downward relative to its pre-braking position, the seat angular velocity is positive; therefore, the deviation σ, obtained by subtracting the actual angular velocity of the seat from the target value A, is negative. When the front part of seat 2 moves upward compared to its position before braking, the seat angular velocity is negative. Therefore, the deviation σ obtained by subtracting the actual angular velocity of the seat from the target value A is positive. In other words, by determining whether the deviation σ is positive or negative, the control unit 11 can detect the rotation direction of the seat 2 in the pitch direction, and can detect the magnitude of the pitch direction movement of the seat 2 based on the magnitude of this value.

[0051] Then, after calculating the deviation σ between the target value A and the actual angular velocity of the seat in step S3, the control unit 11 controls the drive of the actuator 3 based on one of the calculation results of the first angular velocity calculation, the second angular velocity calculation, and the third angular velocity calculation. Furthermore, in this process flow, the processing in step S3 is included in the first angular velocity calculation.

[0052] After the processing in step S3 is performed, the control unit 11 determines whether the rate of change of the seat angular velocity ΔJ1 is greater than or equal to the first set value Ja, or whether the rate of change of the master cylinder pressure ΔM1 is greater than or equal to the first threshold Mb (step S4). ΔJ1 represents the change in seat angular velocity per unit time. ΔM1 represents the change in master cylinder pressure per unit time. Since master cylinder pressure represents brake pedal force, ΔM1 represents the change in brake pedal force per unit time. The first set value Ja is a preset value representing the threshold of seat angular velocity in the first angular velocity calculation. The first threshold Mb is a preset value representing the threshold of master cylinder pressure in the first angular velocity calculation.

[0053] In step S4, the control unit 11 uses the rate of change of the seat angular velocity ΔJ1 and a first set value Ja to determine whether a sinking motion has occurred in the seat 2. If the rate of change of the seat angular velocity ΔJ1 is greater than or equal to the first set value Ja, the control unit 11 determines that a sinking motion has occurred in the seat 2.

[0054] Furthermore, in step S4, the control unit 11 uses the rate of change of the master cylinder pressure ΔM1 and the first threshold Mb to determine whether a sinking motion of the seat 2 will occur. In other words, the control unit 11 determines whether a brake pedal force has been applied that would cause the seat 2 to sink. In short, before the posture of the seat 2 changes from its basic posture, the control unit 11 determines whether a sinking motion of the seat 2 is possible based on the rate of increase of the brake pedal force. If the rate of increase of the brake pedal force is above a predetermined threshold, it is determined that a sinking motion of the seat 2 will occur. Therefore, if the rate of change of the master cylinder pressure ΔM1 is above the first threshold Mb, the control unit 11 determines that a sinking motion of the seat 2 is likely to occur due to a sharp increase in the brake pedal force.

[0055] If the determination in step S4 is affirmative (step S4: "Yes"), the control unit 11 performs calculations to bring the pitch angular velocity of the seat 2 closer to the target value A (step S5). In step S5, control is performed to reduce the absolute value of the deviation σ. In step S5, the control unit 11 performs PID control and FF control. When the absolute value of the deviation σ is large, the control unit 11 performs FF control. And when the absolute value of the deviation σ is small, the control unit 11 performs PID control.

[0056] Additionally, the control unit 11 determines whether the deviation σ is negative (step S6). In step S6, it determines whether the deviation σ calculated in step S3 is negative. In step S6, the control unit 11 determines whether a sinking action of the seat 2 has occurred.

[0057] If the deviation σ is determined to be negative in step S6 (step S6: "Yes"), the control unit 11 determines that a first angular velocity based on the sinking motion has been generated, and outputs a force from the actuator 3 that is opposite in phase to the seat angular velocity (step S7). In step S7, the control unit 11 controls the drive of the actuator 3, and outputs a force from the actuator 3 that acts in the rotational direction opposite to the direction of the first angular velocity. Since the pitching force output from the actuator 3 acts on the seat 2, the sinking motion of the seat 2 is reduced.

[0058] The processing in step S7 is performed when the condition determined in step S4 is affirmative. The condition determined in step S4 is either the condition where the rate of change of seat angular velocity ΔJ1 is greater than or equal to the first set value Ja, or the condition where the rate of change of main cylinder pressure ΔM1 is greater than or equal to the first threshold value Mb.

[0059] Therefore, if the change rate of the seat angular velocity ΔJ1 is greater than or equal to the first set value Ja, and the determination is affirmative in both step S4 and step S6, then in step S7, the control unit 11 determines that a downward movement of the seat 2 has occurred, and outputs a force from the actuator 3 in the opposite direction to the pitch direction of the seat 2. The actuator 3 outputs a force in the opposite direction to the downward movement of the front part of the seat 2, i.e., a force used to reduce the downward movement of the seat 2.

[0060] On the other hand, if the change rate ΔM1 of the master cylinder pressure is greater than or equal to the first threshold Mb, and is therefore determined to be certain in step S4 and step S6, in step S7, the control unit 11 determines that the sinking action of the seat 2 is likely to occur, and outputs a force opposite to the direction of the first angular velocity from the actuator 3. The actuator 3 outputs a force opposite to the direction of the force that the front part of the seat 2 intends to move downward, that is, a force used to suppress the sinking action of the seat 2.

[0061] The scenario in which step S7 is performed is immediately after the start of emergency braking. By performing step S7 on the downward movement of the vehicle Ve during emergency braking, the downward movement of the seat 2 can be suppressed by applying a force opposite in phase to the first angular velocity through actuator 3, thereby suppressing the occupant's movement. Then, after performing step S7, the control routine ends. The case in which step S7 is performed refers to the case where the drive of actuator 3 is controlled based on the calculation result of the first angular velocity.

[0062] If, in step S6, the deviation σ is determined to be non-negative (step S6: "No"), the control unit 11 outputs a force from the actuator 3 that is in phase with the seat angular velocity (step S8). In step S8, the control unit 11 controls the drive of the actuator 3, outputting a force from the actuator 3 that acts in the same direction of rotation as the seat angular velocity (an angular velocity opposite to the direction of the first angular velocity). After the processing in step S8 is performed, the control routine ends.

[0063] If the determination in step S4 is negative (step S4: "No"), the control unit 11 determines whether the rate of change of the seat angular velocity ΔJ2 is greater than or equal to the second set value Jb and less than the third set value Jc, or whether the rate of change of the master cylinder pressure ΔM2 is greater than or equal to the first threshold Mb and less than the second threshold Mc (step S9). ΔJ2 represents the change in seat angular velocity per unit time. ΔM2 represents the change in master cylinder pressure per unit time. The second set value Jb is a preset value representing the lower limit (threshold) of the seat angular velocity in the second angular velocity calculation. The third set value Jc is a preset value representing the upper limit (threshold) of the seat angular velocity in the second angular velocity calculation. The first threshold Mb represents the lower limit (threshold) of the master cylinder pressure in the second angular velocity calculation. The second threshold Mc is a preset value representing the upper limit (threshold) of the master cylinder pressure in the second angular velocity calculation.

[0064] In step S9, the control unit 11 uses the rate of change of the seat angular velocity ΔJ2, the second set value Jb, and the third set value Jc to determine whether a swinging motion has occurred in the seat 2. If the rate of change of the seat angular velocity ΔJ2 is greater than or equal to the second set value Jb and less than the third set value Jc, the control unit 11 determines that a swinging motion has occurred in the seat 2.

[0065] Furthermore, in step S9, the control unit 11 uses the rate of change of master cylinder pressure ΔM2, a first threshold Mb, and a second threshold Mc to determine whether a brake pedal force has occurred that would cause the seat 2 to swing back. In this case, before the seat 2's posture changes from its basic posture, i.e., before any movement related to the pitch direction of the seat 2, the control unit determines whether a swinging motion of the seat 2 is possible based on the rate of change of brake pedal force. Therefore, if the rate of change of master cylinder pressure ΔM2 is greater than or equal to the first threshold Mb and less than the second threshold Mc, the control unit 11 determines that a swinging motion in the seat 2 is possible due to a change in brake pedal force.

[0066] If the determination in step S9 is affirmative (step S9: "Yes"), the control unit 11 performs calculations to bring the pitch angular velocity of the seat 2 closer to the target value A (step S10). In step S10, control is performed to reduce the absolute value of the deviation σ. In step S10, the control unit 11 performs PID control and FF control. If the absolute value of the deviation σ is large, the control unit 11 performs FF control. And if the absolute value of the deviation σ is small, the control unit 11 performs PID control.

[0067] Additionally, the control unit 11 determines whether the deviation σ is negative (step S11). In step S11, it determines whether the deviation σ calculated in step S3 is negative. In step S11, the control unit 11 determines whether a swinging motion of the seat 2 has occurred.

[0068] If, in step S11, the deviation σ is determined to be negative (step S11: "Yes"), the control unit 11 outputs a force from the actuator 3 that is opposite in phase to the seat angular velocity (step S12). In step S12, the control unit 11 controls the drive of the actuator 3, outputting a force from the actuator 3 that acts in the direction of rotation opposite to the direction of the seat angular velocity (an angular velocity opposite to the direction of the second angular velocity). After the processing in step S12 is performed, the control routine ends.

[0069] If, in step S11, the deviation σ is determined to be non-negative (step S11: "No"), the control unit 11 determines that a second angular velocity has been generated as a swing motion, and outputs a force from the actuator 3 that is in phase with the seat angular velocity (step S13). In step S13, the control unit 11 controls the drive of the actuator 3, and outputs a force from the actuator 3 that acts in the same direction of rotation as the second angular velocity. A force acting in the opposite direction of rotation to the first angular velocity is output from the actuator 3. Since the pitch force output from the actuator 3 acts on the seat 2, the swing motion of the seat 2 is reduced.

[0070] The processing in step S13 is performed when the condition is affirmative in step S9. The condition being affirmative in step S9 refers to either the case where the rate of change of the seat angular velocity ΔJ2 is greater than or equal to the second set value Jb and less than the third set value Jc, or the case where the rate of change of the main cylinder pressure ΔM2 is greater than or equal to the first threshold Mb and less than the second threshold Mc.

[0071] Therefore, if the rate of change of the seat angular velocity ΔJ2 is greater than or equal to the second set value Jb and less than the third set value Jc, thus being determined as affirmative in step S9 and negative in step S11, then in step S13, the control unit 11 determines that a swinging motion of the seat 2 has occurred, and outputs a force from the actuator 3 in the same direction as the pitch direction of the seat 2. The actuator 3 outputs a force in the same direction as the upward movement of the front part of the seat 2.

[0072] On the other hand, if the change rate ΔM2 of the main cylinder pressure is greater than or equal to the first threshold Mb and less than the second threshold Mc, thus being determined as affirmative in step S9 and negative in step S11, then in step S13, the control unit 11 determines that the swaying motion of the seat 2 is possible, and outputs a force from the actuator 3 in the same direction as the second angular velocity. The actuator 3 outputs a force in the same direction as the force that the front of the seat 2 intends to move upward.

[0073] The scenario in which step S13 is performed is before the vehicle Ve stops, when a second angular velocity is generated as a swing motion. By performing step S13, the attitude of the seat 2 can be controlled by applying a force with the same phase as the second angular velocity through actuator 3, thereby suppressing the occupant's upper body from moving forward. Then, after performing step S13, the control routine ends. The case in which step S13 is performed refers to the case where the drive of actuator 3 is controlled based on the calculation result of the second angular velocity.

[0074] If the determination in step S9 is negative (step S9: "No"), the control unit 11 determines whether the rate of change of the seat angular velocity ΔJ3 is greater than or equal to the second set value Jb and less than the third set value Jc, or whether the rate of change of the master cylinder pressure ΔM3 is greater than or equal to the first threshold Mb and less than the second threshold Mc (step S14). ΔJ3 represents the change in seat angular velocity per unit time. ΔM3 represents the change in master cylinder pressure per unit time. The second set value Jb represents the lower limit (threshold) of the seat angular velocity in the third angular velocity calculation. The third set value Jc represents the upper limit (threshold) of the seat angular velocity in the third angular velocity calculation. The first threshold Mb represents the lower limit (threshold) of the master cylinder pressure in the third angular velocity calculation. The second threshold Mc represents the upper limit (threshold) of the master cylinder pressure in the third angular velocity calculation.

[0075] In step S14, the control unit 11 uses the rate of change of the seat angular velocity ΔJ3, the second set value Jb, and the third set value Jc to determine whether a swinging motion of the seat 2 has occurred. If the rate of change of the seat angular velocity ΔJ3 is greater than or equal to the second set value Jb and less than the third set value Jc, the control unit 11 determines that a swinging motion has occurred in the seat 2.

[0076] Furthermore, in step S14, the control unit 11 uses the rate of change of the master cylinder pressure ΔM3, the first threshold Mb, and the second threshold Mc to determine whether a brake pedal force has occurred that would cause the seat 2 to swing back. In this case, the control unit determines whether a swinging motion of the seat 2 is possible based on the rate of change of the brake pedal force. Therefore, if the rate of change of the master cylinder pressure ΔM3 is greater than or equal to the first threshold Mb and less than the second threshold Mc, the control unit 11 determines that a swinging motion in the seat 2 is possible due to a sudden change in the brake pedal force.

[0077] If the result in step S14 is negative (step S14: "No"), the control routine ends.

[0078] If the determination in step S14 is affirmative (step S14: "Yes"), the control unit 11 performs calculations to bring the pitch angular velocity of the seat 2 closer to the target value A (step S15). In step S15, control to reduce the absolute value of the deviation σ is executed. In step S15, the control unit 11 executes PID control and FF control. If the absolute value of the deviation σ is large, the control unit 11 executes FF control. And if the absolute value of the deviation σ is small, the control unit 11 executes PID control.

[0079] Additionally, the control unit 11 determines whether the deviation σ is negative (step S16). In step S16, it determines whether the deviation σ calculated in step S3 is negative. In step S16, the control unit 11 determines whether a swinging motion of the seat 2 has occurred.

[0080] If the deviation σ is determined to be negative in step S16 (step S16: "Yes"), the control unit 11 determines that a third triangular velocity based on the oscillation motion is generated, and outputs a force from the actuator 3 that is opposite in phase to the seat angular velocity (step S17). In step S17, the control unit 11 controls the drive of the actuator 3, and outputs a force from the actuator 3 that acts in the rotational direction opposite to the direction of the third angular velocity. Since the pitch force output from the actuator 3 acts on the seat 2, the oscillation motion of the seat 2 is reduced.

[0081] The processing in step S17 is performed when the condition is affirmative in step S14. The condition being affirmative in step S14 refers to either the case where the rate of change of the seat angular velocity ΔJ3 is greater than or equal to the second set value Jb and less than the third set value Jc, or the case where the rate of change of the main cylinder pressure ΔM3 is greater than or equal to the first threshold Mb and less than the second threshold Mc.

[0082] Therefore, if the change rate of the seat angular velocity ΔJ3 is greater than or equal to the second set value Jb and less than the third set value Jc, thus determining a positive result in step S14 and step S16, in step S17, the control unit 11 determines that a swaying motion of the seat 2 has occurred, and outputs a force from the actuator 3 in the opposite direction to the pitch direction of the seat 2. The actuator 3 outputs a force in the opposite direction to the downward movement of the front part of the seat 2, i.e., a force used to reduce the swaying motion of the seat 2.

[0083] On the other hand, if the change rate ΔM3 of the main cylinder pressure is greater than or equal to the first threshold Mb and less than the second threshold Mc, thus being determined as certain in step S14 and step S16, in step S17, the control unit 11 determines that the swaying motion of the seat 2 is likely to occur, and outputs a force opposite to the direction of the third angular velocity from the actuator 3. The actuator 3 outputs a force opposite to the direction of the force that the front part of the seat 2 intends to move downward, that is, a force used to suppress the swaying motion of the seat 2.

[0084] The scenario in which step S17 is performed is before the vehicle Ve stops, when a third angular velocity is generated as a swing motion. By performing step S17, the posture of seat 2 can be controlled in the opposite phase to the third angular velocity, thereby suppressing the swaying of seat 2 and suppressing the vibration of the occupant. Then, after performing step S17, the control routine ends. The case in which step S17 is performed refers to the case in which the drive of actuator 3 is controlled based on the calculation result of the third angular velocity.

[0085] If, in step S16, the deviation σ is determined to be non-negative (step S16: "No"), the control unit 11 outputs a force from the actuator 3 that is in phase with the seat angular velocity (step S18). In step S18, the control unit 11 controls the drive of the actuator 3, outputting a force from the actuator 3 that acts in the same direction of rotation as the seat angular velocity (an angular velocity opposite to the direction of the third angular velocity). After the processing in step S18 is performed, the control routine ends.

[0086] like Figure 4 As shown, the control unit 11 performs steps S3 to S8 as a first angular velocity calculation, performs steps S9 to S13 as a second angular velocity calculation, and performs steps S14 to S18 as a third angular velocity calculation.

[0087] Figure 5 This is a timing diagram showing the control state and seat movement during braking. Figure 5 In this example, the seat control device 1 is described as performing seat control, while a conventional configuration is described as a comparative example. Regarding... Figure 5 The seat angular velocity signals shown are as follows: solid lines represent the actual angular velocity of the embodiment, dashed lines represent the control quantity of the embodiment, and double-dotted lines represent the actual angular velocity of the comparative example. Additionally, seat displacement represents the displacement of the embodiment.

[0088] While vehicle Ve is traveling at a specified speed, the driver depresses the brake pedal, thus sending a braking signal indicating that the brakes have been engaged to seat control device 1 (at time t1). At time t1, vehicle Ve begins to brake.

[0089] Immediately after time t1, the master cylinder pressure increases sharply. This is an emergency braking request. Therefore, the fore-and-aft acceleration acting on seat 2 (hereinafter referred to as seat fore-and-aft acceleration) increases sharply. The seat fore-and-aft acceleration is constant in the rearward direction from the start of braking until the vehicle stops, and its magnitude increases or decreases in this constant direction (rearward direction). At this time, since the rate of change of master cylinder pressure ΔM1 exceeds the first threshold Mb, the seat control device 1 outputs a force from actuator 3 that is opposite in phase to the seat angular velocity. That is, the seat control device 1 controls the drive of actuator 3 to suppress the downward movement of seat 2 after the start of braking. Thus, it is possible to suppress the downward movement of the front part of seat 2. In the case where no control is performed as in the comparative example, a downward movement of the front part of the seat will occur.

[0090] In detail, the embodiment and the comparative example are compared, focusing on the seat angular velocity signal, seat posture, and seat displacement. First, in the comparative example, as shown by the double-dotted line in the seat angular velocity signal, the seat angular velocity deviates significantly from the target value A, with the deviation σ being a negative value. Therefore, as shown in the comparative example of seat posture, a sinking motion occurs in the seat, with the front of the seat moving downwards compared to its position before braking. Furthermore, since the seat posture changes accordingly after this sinking, vibration occurs due to the occupant sliding while rubbing against the seat cushion surface. Figure 5 (shown as a wavy line in the middle).

[0091] In contrast, in the seat posture of this embodiment, the posture of seat 2 changes in that the front of seat 2 moves upward compared to its position before braking. This is because, as shown by the dashed line in the seat angular velocity signal, the control amount that counteracts the change (deviation σ) in the existing seat angular velocity acts on seat 2; that is, a force opposite in phase to the first angular velocity is output from actuator 3. Thus, as shown by the solid line in the seat angular velocity signal, the actual angular velocity shifts to the positive side of the target value A.

[0092] Furthermore, as shown in the forward displacement of the seat, the front part of the seat 2 moves upward relative to the designated position, and as shown in the rear displacement of the seat, the rear part of the seat 2 moves downward relative to the designated position. The designated position is the position before braking or the position of the basic posture. Regarding the forward and rear displacements, as shown in (A), the seat control device 1 actively and gradually changes the seat displacement towards the designated position. That is, after changing the posture of the seat 2 in a way that suppresses the sinking movement of the seat 2, the seat control device 1 gradually changes the posture of the seat 2 towards the basic posture in a way that the occupant sitting on the seat 2 will not notice. This suppresses vibrations caused by the occupant sliding while rubbing against the seat surface of the seat cushion 2a.

[0093] After this, the master cylinder pressure and the seat's fore-and-aft acceleration decrease. At the moment when the brake vibration converges, it is determined that a swinging motion of seat 2 has occurred (time t2). Since it is determined that a second angular velocity, which constitutes a swinging motion, is generated at time t2, the actuator 3 is controlled to drive by outputting a force with the same phase as the second angular velocity. The situation where a swinging motion is determined to occur at time t2 means that the brake pedal force is smaller than at the start of braking, and the fore-and-aft acceleration acting on seat 2 is constant in direction and has decreased.

[0094] Immediately following time t2, in this embodiment, as shown by the dashed line in the seat angular velocity signal, a force with the same phase as the second angular velocity is applied, thereby pushing the actual angular velocity toward the positive side of the target value A. During the period when the seat's fore-and-aft acceleration decreases, a force with the same phase as the second angular velocity is output from actuator 3. As shown in the seat posture of this embodiment, the front of seat 2 is controlled to move upward relative to its position before braking. That is, as shown by the forward displacement of seat displacement, the front of seat 2 moves upward relative to a specified position, and as shown by the backward displacement of seat displacement, the rear of seat 2 moves downward relative to a specified position. Then, when the seat's fore-and-aft acceleration changes from decreasing to increasing, seat control device 1 outputs a force with the opposite phase to the second angular velocity from actuator 3 to stabilize the occupant's posture.

[0095] After that, during the phase when the occupant's upper body stabilizes, it is determined that a third angular velocity is generated as a swing motion (time t3). Since it is determined that a third angular velocity is generated as a swing motion at time t3, the actuator 3 is controlled to drive by outputting a force opposite in phase to the third angular velocity.

[0096] Immediately following time t3, in this embodiment, as shown by the solid line in the seat angular velocity signal, a force opposite in phase to the third angular velocity acts on seat 2, causing the actual angular velocity to shift along the target value A. During the period of increased seat acceleration, a force opposite in phase to the third angular velocity is output from actuator 3. As shown in the seat posture of this embodiment, the front of seat 2 is controlled to move upward relative to its pre-braking position. That is, as shown by the forward displacement of seat displacement, the front of seat 2 moves upward relative to a specified position, and as shown by the backward displacement of seat displacement, the rear of seat 2 moves downward relative to a specified position. This suppresses the downward movement of the front of seat 2, thereby suppressing vibration of seat 2.

[0097] After suppressing the swaying motion, regarding the forward and rearward displacements, as shown in (A), the seat control device 1 actively and gradually changes the seat displacement towards the designated position. That is, after changing the posture of the seat 2 in a way that suppresses the swaying motion of the seat 2, the seat control device 1 gradually changes the posture of the seat 2 towards the basic posture in a way that the occupant sitting on the seat 2 will not notice.

[0098] In contrast, as shown in the comparative example's seat posture, after time t2, the seat continues to swing back and forth in a manner where the front part of the seat moves downwards compared to its pre-braking position, then upwards again compared to its pre-braking position. Furthermore, after this swing, the seat posture changes accordingly. Therefore, after time t2, in the comparative example, vibrations occur due to the occupant sliding while rubbing against the seat cushion surface.

[0099] As explained above, according to the embodiment, the posture of the seat 2 can be appropriately controlled for sinking and swaying movements from the start of braking of the vehicle Ve until it comes to a stop. This improves ride comfort.

[0100] In addition, as a first variation example, such as Figure 6 As shown, the seat 2 can be configured to appropriately control its attitude by damping the entire floor of the vehicle Ve. In the first variation, the actuator 3 is configured to rotate the entire floor of the vehicle Ve in the pitch direction. The seat control device 1 is configured to control the attitude of the entire floor of the vehicle Ve, thereby controlling the attitude of the seat 2, by controlling the drive of the actuator 3.

[0101] Furthermore, as a second modification, an actuator 3 can be included that enables the seat cushion 2a and seat back 2b of the seat 2 to move independently. In this second modification, the seat 2 is configured such that the seat cushion 2a and seat back 2b can move independently. Further, the actuator 3 is configured to include a front actuator that enables the seat cushion 2a to rotate in the pitch direction and a rear actuator that enables the seat back 2b to rotate in the pitch direction. Therefore, by performing seat control, the seat control device 1 can independently control the posture of the seat cushion 2a and the posture of the seat back 2b.

[0102] Furthermore, in the second variation, in Figure 5At time t1, the front actuator of actuator 3 moves the front part of seat cushion 2a upward relative to its pre-braking position, and the rear actuator of actuator 3 moves the rear part of seat back 2b downward relative to its pre-braking position. The posture of seat back 2b is maintained from time t1 until the vehicle stops. That is, the rearward displacement of the seat is maintained at a position that is downward relative to the specified position. On the other hand, the posture of seat cushion 2a actively changes to the specified position during the forward displacement of the seat, as shown in (A). In other words, similar to the forward displacement of the seat in the embodiment, after time t2, the front actuator of actuator 3 moves the front part of seat cushion 2a upward relative to its pre-braking position, changing the posture of seat cushion 2a. Then, at the moment the vehicle Ve stops, the front actuator returns seat cushion 2a to the specified position, and the rear actuator returns seat back 2b to the specified position. This allows seat 2 to return to its basic position.

[0103] [Label Explanation]

[0104] 1 Seat control device; 2 Seat; 2a Seat cushion; 2b Seat backrest; 2c Footrest; 3 Actuator; 11 Control unit; 21 Vehicle speed sensor; 22 Acceleration sensor; 23 Brake stroke sensor; 24 Master cylinder pressure sensor; 25 Seat angular velocity sensor.

Claims

1. A seat control device that controls the actuation of an actuator capable of changing the posture of a seat in which a vehicle occupant is seated, and controls the posture of the seat when the vehicle is braked, characterized in that, If it is determined that a downward movement occurs in the front part of the seat relative to its pre-braking position when braking of the vehicle begins, a first control is executed, in which the actuator outputs a force opposite to the direction of the seat's pitch angular velocity. If it is determined that a swinging motion occurs from the execution of the first control until the vehicle stops, in which the front of the seat moves upward relative to its pre-braking position, a second control is executed, in which the actuator outputs a force in the same direction as the pitch angular velocity of the seat. The sinking action is determined to have occurred when either the rate of change of the seat's pitch angular velocity exceeds a specified value, or the rate of change of the brake pedal force exceeds a threshold value, are met. The situation in which the swinging action is determined is when the brake pedal force is less than when the braking begins, and the forward and backward acceleration acting on the seat is in a constant direction and has decreased.

2. The seat control device according to claim 1, characterized in that, If it is determined that the front of the seat has moved downwards from its pre-braking position after the execution of the second control until the vehicle stops, the first control is executed.

3. The seat control device according to claim 2, characterized in that, Multiple seats are provided on the vehicle. The actuator is provided for each of the multiple seats. The first control and the second control are performed for each of the plurality of seats.

4. The seat control device according to claim 2, characterized in that, Multiple seats are provided on the floor of the vehicle. The actuator is configured to move the entire floor in the vehicle's pitch direction. The first control and the second control are executed in such a way that the entire floor moves in the pitch direction of the vehicle.

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