Vibration damping device

Abstract

To provide a vibration damping device capable of reducing discomfort experienced by an occupant when a vehicle passes over a step.SOLUTION: A vibration damping device includes: an actuator that changes the height of a seat surface of a vehicle seat installed on a floor; a detection unit that detects a step on a road surface along which the vehicle travels; and a processor that is configured to control driving of the actuator such that the jerk of the seat surface when the vehicle passes over the step is smaller than the jerk of the floor when the step is detected.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a vibration damping device.

Background Art

[0002] Patent Document 1 describes a vehicle seat having an acceleration sensor that grasps unevenness of a road surface, and a seat ECU that drives a motor so that a seat body moves in a direction opposite to a direction of vibration transmitted to an occupant sitting on the seat body after the wheels pass over the unevenness of the road surface and vibration is applied to the vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology of Patent Document 1, there are cases where a delay occurs in the response to vibration when the vehicle crosses a step, or the vibration cannot be sufficiently suppressed.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a vibration damping device capable of reducing discomfort of an occupant when the vehicle crosses a step.

Means for Solving the Problems

[0006] The vibration damping device according to the present disclosure includes an actuator that changes the height of a seat surface of a vehicle seat installed on a floor, a detection unit that detects a step on a road surface on which the vehicle travels, and a processor configured to control driving of the actuator so that, when the step is detected, a jerk of the seat surface when the vehicle passes over the step is made smaller than a jerk of the floor.

Effects of the Invention

[0007] According to the present disclosure, a vibration damping device capable of reducing the discomfort of passengers when the vehicle crosses a step can be realized.

Brief Description of the Drawings

[0008]

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DETAILED DESCRIPTION OF THE INVENTION

[0009] The vibration control device according to the embodiment of the present disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that can be replaced by those skilled in the art and are easy to replace, or those that are substantially the same.

[0010] (Embodiment 1) 〔Configuration of Vibration Control Device〕 FIG. 1 is a schematic configuration diagram of a vehicle as a vibration control device according to Embodiment 1. The vehicle 1 as a vibration control device includes a Lidar (Laser Imaging Detection and Ranging) 2 as a detection unit.

[0011] Lidar2 is configured to detect obstacles such as other vehicles and steps ST outside the vehicle 1 using laser light and transmit the detection data to a control device of the vehicle 1 such as an ECU (Electronic Control Unit). For example, it emits laser light around the vehicle 1, receives the laser light reflected by hitting other vehicles or obstacles, and measures and analyzes it to detect other vehicles and obstacles. Note that the detection unit may be configured to be able to detect the step ST of the road surface on which the vehicle 1 travels, and may be, for example, a binocular camera or the like.

[0012] Figures 2 and 3 are a front view and a side view of the seat, and correspond to an enlarged view of the area A in Figure 1. A seat 4 is installed on the floor 3 of the vehicle 1 via an actuator 5. The actuator 5 is driven by the control of the ECU 7 and can change the height of the seating surface 6 of the seat 4.

[0013] The actuator 5 is composed of, for example, four electric actuators that can be independently driven up and down. By driving the four electric actuators simultaneously, the height of the seating surface 6 of the seat 4 can be changed. However, the actuator 5 may have any configuration as long as it can change the height of the seating surface 6 of the seat 4, and the configuration and the number are not particularly limited.

[0014] The ECU 7 controls the vehicle 1. The ECU 7 is configured using a memory and a processor having hardware such as a CPU (Central Processing Unit). Further, when the ECU 7 detects the step ST by the Lidar 2, the ECU 7 controls the drive of the actuator 5 so that the jerk of the seat surface 6 of the seat 4 when the vehicle 1 passes over the step ST is smaller than the jerk of the floor 3. Specifically, the ECU 7 calculates the control amount and control timing of the actuator 5 based on the vehicle speed and road surface shape detected by the Lidar 2, and moves the seat surface 6 of the seat 4 in the protruding direction of the step ST using this calculation result. At this time, it is preferable that the ECU 7 drives the actuator 5 so that the acceleration of the seat surface 6 of the seat 4 reaches the maximum value before the acceleration of the floor 3 reaches the maximum value. The ECU 7 may calculate the acceleration of the vertical vibration input to the vehicle 1 and the timing of vibration generation based on the vehicle speed and road surface shape detected by the Lidar 2, and calculate the control amount and control timing of the actuator 5 using this calculation result.

[0015] 〔Control method of vibration damping device〕 FIG. 4 is a flowchart showing the processing executed by the vibration damping device according to Embodiment 1. As shown in FIG. 4, the ECU 7 determines whether or not the detected step ST is equal to or greater than the threshold value amm based on the information detected by the Lidar 2 (step S1). When the ECU 7 determines that the detected step ST is smaller than the threshold value amm (step S1: No), the process of step S1 is repeated.

[0016] On the other hand, when the ECU 7 determines that the detected step ST is equal to or greater than the threshold value amm (step S1: Yes), the ECU 7 calculates the vehicle speed b and the step amount c based on the information detected by the Lidar 2 (step S2).

[0017] Subsequently, the ECU 7 calculates the actuator control amount d1 and the control timing e1 when the front wheels cross over the step ST (step S3).

[0018] Furthermore, the ECU 7 calculates the actuator control amount d2 and the control timing e2 when the rear wheels cross the step ST (step S4).

[0019] Subsequently, the ECU 7 determines whether it is the start time of the front-wheel crossing control based on the control timing e1 (step S5). When the ECU 7 determines that it is not the start time of the front-wheel crossing control (step S5: No), it enters a standby state where step S5 is repeated.

[0020] On the other hand, when the ECU 7 determines that it is the start time of the front-wheel crossing control (step S5: Yes), the ECU 7 executes control to raise the actuator 5 up to the actuator control amount d1 (step S6).

[0021] After that, the ECU 7 returns the position of the actuator 5 to the actuator control amount 0 (step S7).

[0022] Subsequently, the ECU 7 determines whether it is the start time of the rear-wheel crossing control based on the control timing e2 (step S8). When the ECU 7 determines that it is not the start time of the rear-wheel crossing control (step S8: No), it enters a standby state where step S8 is repeated.

[0023] On the other hand, when the ECU 7 determines that it is the start time of the rear-wheel crossing control (step S8: Yes), the ECU 7 executes control to raise the actuator 5 up to the actuator control amount d2 (step S9).

[0024] After that, the ECU 7 returns the position of the actuator 5 to the actuator control amount 0 (step S10), and a series of processes ends.

[0025] 〔Effect of the Vibration Damping Device〕 FIG. 5 is a timing chart showing the processes executed by the vibration control device according to Embodiment 1. In FIG. 5, a line L1 representing the displacement amount of the actuator 5, a line L2 representing the acceleration of the seat surface 6 of the seat 4 when the vehicle 1 stops, a line L3 representing the acceleration of the floor 3 when the vehicle 1 is running, and a line L4 representing the acceleration of the seat surface 6 of the seat 4 when the vehicle 1 is running are illustrated in order from the top.

[0026] First, when the start time Ta0 of the front-wheel overstep control by the actuator 5 has passed, the actuator 5 is driven according to the control timing e1, and the displacement amount of the actuator 5 shown by the line L1 increases.

[0027] FIG. 6 is a diagram showing the state of the vehicle before crossing a step. FIG. 7 is a diagram showing the state of the seat before the vehicle crosses a step. As shown in FIG. 6, when the vehicle 1 approaches the step ST, as shown in FIG. 7, the actuator 5 is driven and the seat surface 6 of the seat 4 rises. Then, at time Tsa, the acceleration of the seat surface 6 of the seat 4 shown by the line L2 reaches the maximum value.

[0028] Subsequently, when the vehicle 1 runs, since the front wheels of the vehicle 1 cross the step ST, the floor 3 is pushed up by the step ST, and the acceleration of the floor 3 acts upward. This section is illustrated as a push-up section in FIG. 5.

[0029] The time Tf0 when the acceleration of the floor 3 shown by the line L3 starts to increase is the time when the front wheels of the vehicle 1 start to cross the step ST. FIG. 8 is a diagram showing the state of the vehicle while crossing a step. FIG. 9 is a diagram showing the state of the seat while the vehicle crosses a step. As shown in FIG. 8, while the vehicle 1 is crossing the step ST, as shown in FIG. 9, when the seat surface 6 of the seat 4 rises, a negative acceleration acts, and the jerk (the slope of the acceleration) of the seat surface 6 does not increase rapidly.

[0030] Here, the slope from the time Tf0 to the time Tfa when it reaches the maximum value is the jerk of the floor 3. And the slope from the time Ts0 when the acceleration of the seat surface 6 of the seat 4 shown by the line L4 starts to increase to the time Tda when it reaches the maximum value is the jerk of the seat surface 6 of the seat 4.

[0031] Also, the superposition of the acceleration of the seat surface 6 of the seat 4 shown by the line L2 and the acceleration of the floor 3 shown by the line L3 becomes the acceleration of the seat surface 6 of the seat 4 shown by the line L4. At this time, the ECU 7 drives the actuator 5 so that the acceleration of the seat surface 6 of the seat 4 reaches the maximum value at the time Tsa before the time Tfa when the acceleration of the floor 3 reaches the maximum value. As a result, the time Ts0 when the acceleration of the seat surface 6 of the seat 4 starts to increase is earlier than the time Tf0 when the acceleration of the floor 3 starts to increase, and the jerk of the seat surface 6 of the seat 4 becomes smaller than the jerk of the floor 3.

[0032] According to the first embodiment described above, since the jerk of the seat surface 6 of the seat 4 is smaller than the jerk of the floor 3, it is possible to reduce the discomfort of the occupant when the vehicle 1 crosses the step ST.

[0033] (Second Embodiment) The vehicle 1 as a vibration damping device according to the second embodiment may have the same configuration as the first embodiment, so the description is omitted. In the first embodiment, the ECU 7 executes control to raise the actuator 5, but in the second embodiment, the ECU 7 executes control to lower the actuator 5.

[0034] FIG. 10 is a flowchart showing the processing executed by the vibration damping device according to the second embodiment. In FIG. 10, the same processes as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0035] After step S2, the ECU 7 calculates the actuator control amount d21 and the control timing e21 when the front wheels cross the step ST (step S21).

[0036] Furthermore, the ECU 7 calculates the actuator control amount d22 and the control timing e22 when the rear wheels cross the step ST (step S22).

[0037] After that, when ECU 7 determines that it is the start time of the front-wheel overstep control based on the control timing e21 (step S5: Yes), ECU 7 executes control to lower the actuator 5 to the actuator control amount d21 (step S23).

[0038] Also, when ECU 7 determines that it is the start time of the rear-wheel overstep control based on the control timing e22 (step S8: Yes), ECU 7 executes control to lower the actuator 5 to the actuator control amount d22 (step S24).

[0039] FIG. 11 is a timing chart showing the processes executed by the vibration control device according to Embodiment 2. In FIG. 11, similar to FIG. 5, a line L11 representing the displacement amount of the actuator 5, a line L12 representing the acceleration of the seat surface 6 of the seat 4 when the vehicle 1 stops, a line L13 representing the acceleration of the floor 3 when the vehicle 1 is running, and a line L14 representing the acceleration of the seat surface 6 of the seat 4 when the vehicle 1 is running are illustrated in order from the top.

[0040] In Embodiment 2, when passing the start time Ta0 of the front-wheel overstep control by the actuator 5, the actuator 5 is driven according to the control timing e21, and the displacement amount of the actuator 5 shown in the line L11 decreases. This means that the seat surface 6 of the seat 4 is lowered by the actuator 5. That is, ECU 7 drives the actuator 5 to move the seat surface 6 of the seat 4 in the direction opposite to the protruding direction of the step ST.

[0041] FIG. 12 is a diagram showing the state of the seat before the vehicle crosses a step. As shown in FIG. 6, when the vehicle 1 approaches the step ST, as shown in FIG. 12, the actuator 5 is driven and the seat surface 6 of the seat 4 is lowered. Then, a negative acceleration acts on the occupant O, and the occupant O sinks into the seat 4. Then, when the time Tsa is reached, the upward acceleration of the seat surface 6 of the seat 4 shown in the line L12 reaches the maximum value.

[0042] FIG. 13 is a diagram showing the state of the seat immediately before the vehicle crosses a step. As the vehicle 1 approaches the step ST further, immediately before the vehicle 1 crosses the step ST, as shown in FIG. 12, the occupant O accelerates upward in order to receive the repulsion of the seat 4.

[0043] FIG. 14 is a diagram showing the state of the seat while the vehicle crosses a step. As shown in FIG. 8, while the vehicle 1 is crossing the step ST, as shown in FIG. 14, the seat 4 is pushed up by the step ST, but the jerk (the slope of the acceleration) of the seat surface 6 of the seat 4 does not increase rapidly.

[0044] Here, the ECU 7 drives the actuator 5 so that the acceleration of the seat surface 6 of the seat 4 reaches the maximum value at the time Tsa before the acceleration of the floor 3 reaches the maximum value at the time Tfa. As a result, the time Ts0 when the acceleration of the seat surface 6 of the seat 4 starts to increase becomes earlier than the time Tf0 when the acceleration of the floor 3 starts to increase, and the jerk of the seat surface 6 of the seat 4 becomes smaller than the jerk of the floor 3.

[0045] According to the second embodiment described above, since the jerk of the seat surface 6 of the seat 4 is smaller than the jerk of the floor 3, the discomfort of the occupant when the vehicle 1 crosses the step ST can be reduced.

[0046] FIG. 15 is a diagram showing the first peak jerk. As shown in FIG. 15, according to the second embodiment, the first peak jerk on the seat surface 6 of the seat 4 can be reduced by 25% compared with the conventional case.

[0047] FIG. 16 is a diagram showing the slope, linearity, and sensory evaluation points of the acceleration of the seat surface with respect to the predictive control time. The predictive control time represents how far before the vehicle 1 crosses the step ST the actuator 5 is driven.

[0048] First, the inclination of the seat surface 6 of the seat 4 shown by the line L21 decreases as the pre-reading control time increases. However, the linearity of the inclination of the seat surface 6 of the seat 4 shown by the line L22 rapidly decreases when the pre-reading control time exceeds a certain value. Therefore, the sensory evaluation point shown by the line L23 is the best in the region B. Thus, it is preferable that the ECU 7 calculates the control timing of the actuator 5 at which the linearity of the inclination of the seat surface 6 of the seat 4 becomes equal to or greater than a predetermined value.

[0049] (Embodiment 3) The vibration damping device according to Embodiment 3 includes an acceleration sensor that detects, as a detection unit, the acceleration when the front wheels of the vehicle 1 cross a step ST. Then, in Embodiment 3, the ECU 7 calculates the control amount and control timing of the actuator 5 according to the acceleration when the front wheels cross the step ST detected by the detection unit.

[0050] FIG. 17 is a flowchart showing the processing executed by the vibration damping device according to Embodiment 3. As shown in FIG. 17, the ECU 7 determines whether the vibration when the front wheels cross a step is greater than a threshold value T based on the acceleration detected by the acceleration sensor (step S31).

[0051] When the ECU 7 determines that the vibration when the front wheels cross a step is less than the threshold value T (step S31: No), the process of step S31 is repeated.

[0052] On the other hand, when the ECU 7 determines that the vibration when the front wheels cross a step is greater than the threshold value T (step S31: Yes), the ECU 7 calculates an actuator control amount d31 and control timing e31 suitable for the rear wheels to cross a step (step S32).

[0053] Subsequently, the ECU 7 determines whether it has reached the start time of the rear-wheel crossing control based on the control timing e31 (step S33). When the ECU 7 determines that it has not reached the start time of the rear-wheel crossing control (step S33: No), it enters a standby state where step S33 is repeated.

[0054] On the other hand, when the ECU 7 determines that the start time of the rear-wheel overstep control has arrived (step S33: Yes), the ECU 7 executes control to lower the actuator 5 to the actuator control amount d31 (step S34).

[0055] After that, the ECU 7 returns the position of the actuator 5 to the actuator control amount 0 (step S35), and a series of processes ends.

[0056] This vibration control device is suitable for suppressing the vibration of the seat 4 located behind the vehicle 1 with a long overall length of the vehicle 1. It is difficult for the vibration when the front wheels of the vehicle 1 cross the step ST to be transmitted to the rear seat 4. Therefore, the vibration detection unit detects the vibration when the front wheels cross the step ST, and the ECU 7 may calculate the actuator control amount and control timing when the rear wheels cross the step ST based on the detected vibration.

[0057] FIG. 18 is a diagram showing the state before the rear wheels of the vehicle cross the step. As shown in FIG. 18, when the rear wheels of the vehicle 1 approach the step ST, as in FIG. 12, the actuator 5 is driven and the seat surface 6 of the seat 4 descends. Then, a negative acceleration acts on the occupant O, and the occupant O sinks into the seat 4.

[0058] FIG. 19 is a diagram showing the state immediately before the rear wheels of the vehicle cross the step. As shown in FIG. 19, as shown in FIG. 19, while the rear wheels of the vehicle 1 are crossing the step ST, as in FIG. 14, the seat 4 is pushed up by the step ST, but the jerk (the slope of the acceleration) of the seat surface 6 of the seat 4 does not increase rapidly.

[0059] Further, the ECU 7 may compare the distance LF from the seat 4 to the front wheels and the distance LR from the seat 4 to the rear wheels, and make the control amount of the actuator 5 on the side with the smaller distance larger than the control amount of the actuator 5 on the side with the larger distance. Furthermore, the ECU 7 may control the actuator 5 so that the ratio of the maximum value of the acceleration of the seat surface 6 of the seat 4 is LR:LF.

[0060] (Embodiment 4) The vibration control device according to Embodiment 4 has an acceleration sensor that detects the acceleration of the seating surface 6 of the seat 4 as a detection unit. Then, the ECU 7 drives the actuator 5 in a state where the vehicle 1 is stopped, and stores the passage of time of the vertical movement amount of the seating surface 6 of the seat 4. Further, the ECU 7 calculates the actuator control amount and the control timing based on the passage of time of the vertical movement amount of the seating surface 6 of the seat 4 that has been stored. Note that the vibration control device has an acceleration sensor that detects the acceleration of the floor 3 or the vehicle body of the vehicle 1 as a detection unit, and based on the passage of time of the vertical movement amount of the floor 3 or the vehicle body of the vehicle 1 detected by the detection unit, the actuator control amount and the control timing may be calculated.

[0061] FIG. 20 is a timing chart showing the process executed by the vibration control device according to Embodiment 4. When the displacement amount of the actuator 5 shown by the line L31 is reduced, the seating surface 6 of the seat 4 descends.

[0062] FIG. 21 is a diagram showing the state of the occupant and the seat in the first half of the descent. As shown in FIG. 21, in the first half of the descent, the seat 4 descends and the occupant O sinks into the seating surface 6 of the seat 4. More specifically, at the initial stage of the descent, the weight of the occupant O does not act on the seating surface 6 of the seat 4, so the displacement amount of the seating surface 6 of the seat 4 shown by the line L32 changes to the stretching side.

[0063] After that, the displacement amount of the seating surface 6 of the seat 4 turns to the compression side and rebounds again in the second half of the descent. FIG. 22 is a diagram showing the state of the occupant and the seat in the second half of the descent. As shown in FIG. 22, in the second half of the descent, the occupant O is pushed upward by the seating surface 6 of the seat 4. The ECU 7 can perform control according to the occupant O by calculating the actuator control amount and the control timing based on this rebound timing.

[0064] Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Description of Symbols

[0065] 1 Vehicle 2 Lidar 3 Floor 4 Seat 5 Actuator 6 Seat surface 7 ECU

Claims

1. An actuator for changing the height of the seat surface of a vehicle seat installed on the floor, a detection unit for detecting a step on the road surface on which the vehicle travels, a processor configured to control the drive of the actuator so that when the step is detected, the jerk of the seat surface when the vehicle passes over the step is made smaller than the jerk of the floor, a vibration damping device comprising the same.

2. The vibration damping device according to claim 1, wherein the processor moves the seat surface in the protruding direction of the step.

3. The vibration damping device according to claim 1, wherein the processor calculates a control amount and a control timing of the actuator.

4. The vibration damping device according to claim 1, wherein the processor drives the actuator so that the acceleration of the seat surface reaches a maximum value before the acceleration of the floor reaches a maximum value.

5. The detection unit is a stereo camera or LiDAR, The vibration damping device according to claim 1, wherein the processor calculates a control amount and a control timing of the actuator based on the vehicle speed and the road surface shape detected by the detection unit.

Images