Suspension control device

Abstract

[Problem] To provide a suspension control device that can improve the feeling of agility and the feeling of ground contact when turning while riding a saddle-type vehicle. [Solution] A suspension control device 1 controls variable damping force shock absorbers Df, Dr that can adjust the damping force and are interposed between a vehicle body B of a saddle-type vehicle M and a front wheel (vehicle wheel) Wf, and the vehicle body B and a rear wheel (front wheel) Wr, respectively. The suspension control device 1 comprises: a bank angle detection unit 2 that detects a bank angle θ, which is the angle of inclination of the vehicle body B in the left-right direction; a bank angular velocity detection unit 3 that detects a bank angular velocity ω of the vehicle body B; and a control unit 5 that controls the damping force of the variable damping force shock absorbers Df, Dr on the basis of the bank angle θ and the bank angular velocity ω.

Description

Suspension control device

[0001] The present invention relates to a suspension control device.

[0002] As a suspension control device that controls the damping force of a variable damping shock absorber that is interposed between the body and wheels of a saddle-type vehicle and can adjust the damping force, for example, as disclosed in JP2017-165297A, there is a bank angle detection unit that detects the bank angle in the left-right direction of the vehicle body, and a control unit that performs control to increase the damping force on the extension side of the variable damping shock absorber when the bank angle increases.

[0003] JP2017-165297A

[0004] According to the conventional suspension control device, since the damping force generated by the variable damping shock absorber is increased during turning of the saddle-type vehicle, the posture of the vehicle body during turning of the saddle-type vehicle can be appropriately maintained.

[0005] However, in the conventional suspension control device, regardless of whether the bank angle of the vehicle body increases and the vehicle body leans greatly, or whether the bank angle of the vehicle body decreases and the vehicle body rises, since the damping force of the variable damping shock absorber is controlled depending only on the bank angle, the damping force of the variable damping shock absorber is not optimal for the running condition of the saddle-type vehicle. Therefore, there is room for improving the ground contact feeling and the light feeling of the vehicle body rising during turning of the saddle-type vehicle.

[0006] Therefore, an object of the present invention is to provide a suspension control device that can improve the ground contact feeling and the light feeling of the vehicle body rising during turning of a saddle-type vehicle.

[0007] To achieve the above object, the suspension control device of the present invention is a suspension control device that controls a variable damping shock absorber that is interposed between the body and wheels of a saddle-type vehicle and can adjust the damping force, and includes a bank angle detection unit that detects the bank angle which is the inclination angle in the left-right direction of the vehicle body, a bank angular velocity detection unit that detects the bank angular velocity of the vehicle body, and a control unit that controls the damping force of the variable damping shock absorber based on the bank angle and the bank angular velocity.

[0008] With the suspension control device configured in this way, the damping force of the variable damping shock absorber is controlled based on the bank angle and bank angular velocity of the vehicle body. This allows the system to understand whether the vehicle body is leaning or straightening up, and to generate a damping force in the variable damping shock absorber that is suitable not only for when the vehicle body is leaning but also for when the vehicle body is straightening up.

[0009] Figure 1 shows a suspension control device and a variable damping shock absorber in one embodiment mounted on a saddle-type vehicle. Figure 2 shows the configuration of the suspension control device. Figure 3 is a schematic diagram of the variable damping shock absorber. Figure 4 is a diagram illustrating the relationship between the vertical and lateral acceleration of the vehicle body and the bank angle. Figure 5 is a diagram illustrating the relationship between the angular velocity in the pitch and yaw directions of the vehicle body and the bank angle. Figure 6 shows the relationship between the bank angle and control commands when the vehicle body is leaning. Figure 7 shows the relationship between the bank angle and control commands when the vehicle body is straightening. Figure 8 is a flowchart showing an example of the calculation processing procedure for control commands in a suspension control device of one embodiment. Figure 9 is a schematic diagram of a variable damping shock absorber in which the extension damping force and compression damping force can be adjusted independently. Figure 10 is a diagram illustrating the change in control commands when the leaning or straightening of the vehicle body is completed. Figure 11 is a diagram illustrating the change in control commands when the leaning or straightening of the vehicle body is continuous. Figure 12 illustrates the changes in bank angle and control commands when the vehicle body alternates between leaning and straightening. Figure 13 is a flowchart showing another example of the calculation processing procedure for control commands in a suspension control device according to one embodiment.

[0010] The present invention will be described below based on the embodiments shown in the figures. In one embodiment, the suspension control device 1 controls adjustable damping force shock absorbers Df and Dr, which are interposed between the vehicle body B of the saddle-type vehicle M and the front wheel Wf and rear wheel Wr, and together with these adjustable damping force shock absorbers Df and Dr, constitute a suspension system.

[0011] As shown in Figures 1 and 2, the suspension control device 1 includes a bank angle detection unit 2 that detects the bank angle θ, which is the left-right tilt angle of the vehicle body B; a bank angular velocity detection unit 3 that detects the bank angular velocity ω of the vehicle body B; a speed detection unit 4 that detects the driving speed V of the saddle-type vehicle M; and a control unit 5 that controls the damping force of the variable damping shock absorbers Df and Dr based on the bank angle θ and bank angular velocity ω.

[0012] The following describes in detail each part of the suspension system. In this embodiment, the saddle-type vehicle M is a motorcycle. The variable damping shock absorber Df on the front wheel Wf side is built into the front fork (not shown), which is interposed between the vehicle body B and the front wheel Wf, along with the front suspension spring (not shown), and exerts damping force when it extends and contracts. Furthermore, the variable damping shock absorber Dr on the rear wheel side is interposed between the vehicle body B and the rear wheel Wr, which is the wheel, via a swing arm (not shown), along with the rear suspension spring (not shown), and exerts damping force when it extends and contracts.

[0013] In this embodiment, both the front wheel-side variable damping shock absorber Df and the rear wheel-side variable damping shock absorber Dr, as shown in Figure 3, include a cylinder 20, a piston 21 slidably inserted into the cylinder 20 and dividing the cylinder 20 into an extension chamber R1 and a compression chamber R2, which are filled with liquid, a piston rod 22 movably inserted into the cylinder 20 and connected to the piston 21, and a damping valve 23 provided on the piston 21 that connects the extension chamber R1 and the compression chamber R2, and The cylinder is configured to include a bypass passage 24 that bypasses the damping valve 23 and connects the extension chamber R1 and the compression chamber R2, a damping force adjustment valve 25 provided in the middle of the bypass passage 24, a reservoir 26 that supplies and discharges excess or insufficient liquid in the cylinder 20 by a piston rod 22 that moves in and out of the cylinder 20, a suction passage 28 that allows only the flow of liquid from the reservoir 26 to the compression chamber R2, and a compression valve 29 that provides resistance to the flow of liquid from the compression chamber R2 to the reservoir 26.

[0014] The damping force adjustment valve 25, although not shown in detail, in this embodiment comprises a valve body connected to the actuator 27 via a control rod 27a and a valve seat provided in the bypass passage 24. The valve body is driven relative to the valve seat to adjust the flow area, thereby changing the resistance applied to the flow of liquid moving between the extension chamber R1 and the compression chamber R2 through the bypass passage 24, and thus the damping force generated when the variable damping force shock absorbers Df and Dr expand and contract can be adjusted. In the variable damping force shock absorbers Df and Dr of this embodiment, when the current supplied to the actuator 27 by the damping force adjustment valve 25 increases, the valve body moves toward the valve seat, reducing the flow area. Therefore, increasing the current supplied to the actuator 27 increases the resistance applied to the flow of liquid passing through the bypass passage 24, increasing the damping coefficient of the variable damping force shock absorbers Df and Dr, and increasing the damping force when the variable damping force shock absorbers Df and Dr expand and contract. On the other hand, reducing the current supplied to the actuator 27 reduces the resistance to the liquid flow through the bypass passage 24, which reduces the damping coefficient of the variable damping shock absorbers Df and Dr, and thus reduces the damping force when the variable damping shock absorbers Df and Dr expand and contract.

[0015] The damping force adjustment valve 25 is merely an example, and any valve that can adjust the damping force generated by the variable damping force shock absorbers Df and Dr is acceptable; therefore, it may be a valve with a different structure. Accordingly, the damping force adjustment valve 25 may be, for example, an electromagnetic relief valve with adjustable opening pressure, a rotary valve disclosed in Japanese Patent Application Publication No. 05-238235, or even a spool valve. Furthermore, if the damping force is generated solely by the damping force adjustment valve 25, the damping valve 23 may be eliminated.

[0016] Furthermore, if the liquid used in the variable damping shock absorbers Df and Dr is an electroviscous fluid or a magnetorheological fluid, the damping force may be adjusted by applying an electric or magnetic field to the passage through which the liquid flows, instead of using a damping force adjustment valve. In addition, the structure of the variable damping shock absorbers Df and Dr may be changed to adopt a different structure if it is possible to adjust the damping force generated during expansion and contraction.

[0017] Next, the suspension control device 1 includes the aforementioned decoy, a bank angle detection unit 2 that detects the bank angle θ, which is the left-right tilt angle of the vehicle body B, a bank angular velocity detection unit 3 that detects the bank angular velocity ω of the vehicle body B, a speed detection unit 4 that detects the driving speed V of the saddle-type vehicle M, and a control unit 5 that controls the damping force of the variable damping shock absorbers Df and Dr based on the bank angle θ and bank angular velocity ω.

[0018] The bank angular velocity detection unit 3 is, for example, a gyro sensor and is installed on the body B of the saddle-type vehicle M. In addition to the roll rate, which is the rotational speed of the vehicle body B along its longitudinal axis, it can also detect the pitch rate, which is the rotational speed of the vehicle body B along its lateral axis, and the yaw rate, which is the rotational speed of the vehicle body B along its vertical axis. The bank angular velocity ω is the rotational speed of the vehicle body B in the lateral direction, and is therefore equal to the roll rate detected by the bank angular velocity detection unit 3. The bank angular velocity detection unit 3 is preferably installed at the center of gravity of the vehicle body B, but it is not always possible to install it at the center of gravity of the vehicle body B. However, calibration allows the bank angular velocity ω at the center of gravity of the vehicle body B to be detected regardless of the installation location on the vehicle body B. The bank angular velocity ω obtained by the bank angular velocity detection unit 3 takes a positive value when the tilt of the vehicle body B increases to the right, and a negative value when the tilt of the vehicle body B increases to the left. The calculation is performed so that a negative value is obtained when the vehicle body B is tilted. Furthermore, since the bank angular velocity detection unit 3 only needs to be able to detect the bank angular velocity ω, it may be a sensor that only detects the roll rate.

[0019] The bank angle detection unit 2 includes an acceleration sensor 6 installed on the body B of the saddle-type vehicle M, and a bank angle calculation unit 7 that calculates the bank angle θ from the acceleration detected by the acceleration sensor 6.

[0020] The acceleration sensor 6 is installed on the body B of the saddle-type vehicle M and is a three-axis acceleration sensor that detects acceleration in three axes: acceleration Gx in the longitudinal direction, acceleration Gy in the lateral direction, and acceleration Gz in the vertical direction of the vehicle body B.

[0021] The bank angle calculation unit 7 determines the bank angle θ, which is the tilt angle of the vehicle body B in the left-right direction, based on the accelerations Gx, Gy, and Gz of the vehicle body B detected by the acceleration sensor 6 in the longitudinal, left-right, and up-down directions. As shown in Figure 4, when the vehicle body B banks by an angle θ with respect to the vertical axis Ver, if centrifugal force is ignored, the resultant force of the left-right acceleration GOy and the up-down acceleration GOz acting on the center of gravity O of the vehicle body B is equal to the acceleration due to gravity g. Therefore, the bank angle calculation unit 7 first determines the vertical axis direction of the vehicle body B from the three-axis accelerations Gx, Gy, and Gz detected by the acceleration sensor 6 through calibration, and uses the transformation matrix obtained through calibration to determine the accelerations GOy and GOz at the center of gravity of the vehicle body B from the accelerations Gy and Gz detected by the acceleration sensor 6, and then determines the bank angle θ from the determined accelerations GOy and GOz. The bank angle θ determined by the bank angle detection unit 2 is calculated such that, with the vehicle body B standing vertically as 0 degrees, it takes a positive value when the vehicle body B is tilted to the right, and a negative value when the vehicle body B is tilted to the left. The value of the bank angle θ may take a negative value when the vehicle body B is tilted to the right and a positive value when the vehicle body B is tilted to the left, but in that case, the bank angular velocity ω will also take a negative value when the tilt of the vehicle body B to the right increases and a positive value when the tilt of the vehicle body B to the left increases.

[0022] The bank angle calculation unit 7 may determine the bank angle θ based on the angular velocities p and ψ in the pitch and yaw directions of the vehicle body B detected by the bank angular velocity detection unit 3. As shown in Figure 5, if the pitch angular velocity p and yaw angular velocity ψ are obtained, the bank angle θ of the vehicle body B with respect to the vertical axis Ver can be uniquely determined. The vertical axis Ver can be determined by calibrating the acceleration sensor 6 in the bank angle detection unit 2. The bank angle calculation unit 7 may also determine the bank angle θ by integrating the bank angular velocity ω detected by the bank angular velocity detection unit 3. Furthermore, the bank angle detection unit 2 and the bank angular velocity detection unit 3 may be inertial measurement units capable of detecting the bank angle θ and bank angular velocity ω.

[0023] The speed detection unit 4 is a speed sensor that detects the travel speed V of the saddle-type vehicle M. Since the saddle-type vehicle M is almost always equipped with a speed sensor, the travel speed V may be obtained by using the speed sensor of the saddle-type vehicle M.

[0024] Next, as shown in Figure 2, the control unit 5 includes a vehicle body condition determination unit 51 that determines the tilt of the vehicle body B based on the bank angle θ and bank angular velocity ω, a command generation unit 52 that generates control commands Ff and Fr for controlling the damping force of each variable damping force shock absorber Df and Dr based on the absolute value of the bank angle θ and the determination result of the vehicle body condition determination unit 51, a correction unit 53 that corrects the control commands Ff and Fr based on the driving speed V, and a driver 54 that receives the input of the corrected control commands Ffc and Frc by the correction unit 53 and supplies current to the actuator 27 in the damping force adjustment valve 25 of the variable damping force shock absorbers Df and Dr.

[0025] The vehicle body condition determination unit 51 determines, based on the bank angle θ and bank angular velocity ω, whether the vehicle body B is changing in a direction that causes it to tilt to the left or right, or in a direction that causes it to straighten up.

[0026] The vehicle body condition determination unit 51 determines that when the bank angle θ is positive and the bank angular velocity ω is positive, and when the bank angle θ is negative and the bank angular velocity ω is negative, the tilt of the vehicle body B is changing in a direction that increases, and therefore the vehicle body B is in a leaning state where it is tilting to the left or right. Specifically, the vehicle body condition determination unit 51 determines that the vehicle body B is in a leaning state when the sign of the value obtained by multiplying the bank angle θ by the bank angular velocity ω is positive.

[0027] Furthermore, the vehicle body condition determination unit 51 determines that when the bank angle θ is positive and the bank angular velocity ω is negative, and when the bank angle θ is negative and the bank angular velocity ω is positive, the tilt of the vehicle body B is changing in a direction that decreases, and therefore the vehicle body B is changing in a direction that straightens up. Specifically, the vehicle body condition determination unit 51 determines that the vehicle body B is straightening up if the sign of the value obtained by multiplying the bank angle θ by the bank angular velocity ω is negative.

[0028] The command generation unit 52 generates control commands Ff and Fr for controlling the damping force of each variable damping force shock absorber Df and Dr based on the absolute value of the bank angle θ and the judgment result of the vehicle body condition judgment unit 51.

[0029] When the vehicle body B is leaning in a tilting state, the command generation unit 52 generates control commands Ff and Fr that increase the damping force of the variable damping shock absorbers Df and Dr as the absolute value of the bank angle θ increases. Specifically, the command generation unit 52 multiplies the absolute value of the bank angle θ by a predetermined gain G1 to generate control commands Ff and Fr that instruct the current to be supplied to the actuator 27 in the damping force adjustment valve 25 of each variable damping shock absorber Df and Dr. When the vehicle body B is leaning in a tilting state, the control commands Ff and Fr are proportional to the bank angle θ, so as shown in Figure 6, as the absolute value of the bank angle θ increases, it becomes a signal to increase the current supplied to the actuator 27. When the vehicle body B is leaning, the command generation unit 52 increases the control commands Ff and Fr in proportion to the absolute value of the bank angle θ. As the absolute value of the bank angle θ increases, the damping coefficients of the variable damping shock absorbers Df and Dr increase, and the damping force generated by the variable damping shock absorbers Df and Dr increases. If the optimal gain differs between the variable damping shock absorber Df on the front wheel side and the variable damping shock absorber Dr on the rear wheel side, the value of the gain G1 may be set to different values ​​for the front and rear wheels when generating the control commands Ff and Fr. Furthermore, when the vehicle body B is leaning, the command generation unit 52 generates control commands Ff and Fr such that the extension damping force in the variable damping shock absorber Df on the front wheel side is higher than the compression damping force, and the compression damping force in the variable damping shock absorber Dr on the rear wheel side is higher than the extension damping force. If the extension damping force in the front-wheel variable damping shock absorber Df is set higher than the compression damping force, and the compression damping force in the rear-wheel variable damping shock absorber Dr is set higher than the extension damping force, the vehicle body B tends to tilt forward, making it easier for the driver of the saddle-type vehicle M to lean the vehicle body B over. If the extension and compression damping forces of the variable damping shock absorbers Df and Dr are to be adjustable, a stroke sensor is provided to detect the stroke displacement of the variable damping shock absorbers Df and Dr. The control unit 5 then understands the extension and contraction status of the variable damping shock absorbers Df and Dr from the stroke displacement detected by the stroke sensor and generates control commands Ff and Fr to be given to the damping force adjustment valve 25 to control the extension and compression damping forces.Furthermore, if the extension damping force and compression damping force of the variable damping force shock absorbers Df and Dr are to be adjustable, the variable damping force shock absorbers Df and Dr may, for example as shown in Figure 9, instead of the bypass passage 24 and damping force adjustment valve 25 in the variable damping force shock absorbers Df and Df shown in Figure 3, include an extension bypass passage 30 that allows only the flow of hydraulic fluid from the extension chamber R1 to the compression chamber R2, a compression bypass passage 31 that allows only the flow of hydraulic fluid from the compression chamber R2 to the reservoir 26, an extension damping force adjustment valve 32 provided in the extension bypass passage 30, a compression damping force adjustment valve 33 provided in the compression bypass passage 31, an actuator 34 that drives the extension damping force adjustment valve 32, and an actuator 35 that drives the compression damping force adjustment valve 33. Furthermore, the structure of the variable damping shock absorbers Df and Dr is not limited to the structure shown in Figure 9; the design can be arbitrarily modified as long as the extension damping force and compression damping force can be adjusted independently.

[0030] Thus, when the vehicle body B is leaning, the command generation unit 52 generates control commands Ff and Fr to increase the damping force of the variable damping shock absorbers Df and Dr according to the absolute value of the bank angle θ. In situations where the vehicle body B leans as the saddle-type vehicle M begins to turn and the absolute value of the bank angle θ increases, the variable damping shock absorbers Df and Dr generate high damping force, improving the ground contact of the front wheels Wf and rear wheels Wr.

[0031] In this embodiment, the variable damping shock absorbers Df and Dr increase the damping coefficient when the current supplied to the actuator 27 by the damping force adjustment valve 25 increases, and decrease the damping coefficient when the current supplied to the actuator 27 decreases. Therefore, when the vehicle body B is leaning, the command generation unit 52 generates control commands Ff and Fr that are proportional to the bank angle θ. If the variable damping shock absorbers Df and Dr decrease the damping coefficient when the current supplied to the actuator 27 increases, and increase the damping coefficient when the current supplied to the actuator 27 decreases, the command generation unit 52 should generate control commands Ff and Fr that decrease the damping coefficient of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ increases, in the opposite case.

[0032] Furthermore, when the vehicle body B is in an uprighting state, the command generation unit 52 generates control commands Ff and Fr that increase the damping force of the variable damping shock absorbers Df and Dr as the absolute value of the bank angle θ decreases. Specifically, the command generation unit 52 calculates the formula Ff(Fr) = A × (|θmax| - |θ|) to generate control commands Ff and Fr that instruct the current supplied to the actuator 27 in the damping force adjustment valve 25 of each variable damping shock absorber Df and Dr. The coefficient A is an arbitrary coefficient for determining the control commands Ff and Fr, and is set so that the damping coefficients of the variable damping shock absorbers Df and Dr are appropriate when the vehicle body B of the saddle-type vehicle M is uprighting. Also, |θmax| in the above formula is the maximum absolute value of the bank angle θ detected from when the vehicle body B is leaned down until it starts to upright. For detecting |θmax|, the control unit 5 may, for example, adopt the absolute value of the bank angle θ detected by the bank angle calculation unit 7 as |θmax| when the sign of the bank angular velocity ω detected by the bank angular velocity detection unit 3 changes or becomes zero. Alternatively, instead of θmax, the control commands Ff and Fr may be obtained by subtracting |θ| from a preset angle and multiplying the result by a coefficient A.

[0033] Furthermore, if the optimal damping coefficient differs between the variable damping shock absorber Df on the front wheel side and the variable damping shock absorber Dr on the rear wheel side, the control command Ff may be calculated as Ff = Af × (|θmax| - |θ|), and the control command Fr may be calculated as Fr = Ar × (|θmax| - |θ|), and the coefficients Af and Ar in the formulas may be set to different values ​​for the front wheel and rear wheel when generating the control commands Ff and Fr.

[0034] When the vehicle body B is in the upright position, the control commands Ff and Fr become signals that reduce the current supplied to the actuator 27 as the absolute value of the bank angle θ increases, as shown in Figure 7. When the vehicle body B is in the upright position, the command generation unit 52 reduces the control commands Ff and Fr as the absolute value of the bank angle θ increases. Therefore, as the absolute value of the bank angle θ decreases, the damping coefficients of the variable damping shock absorbers Df and Dr increase, and the damping force generated by the variable damping shock absorbers Df and Dr increases.

[0035] Thus, when the vehicle body B is in an upright position, the command generation unit 52 generates control commands Ff and Fr to increase the damping force of the variable damping shock absorbers Df and Dr as the absolute value of the bank angle θ decreases. In situations where the saddle-type vehicle M is in the latter half of cornering and the vehicle body B is upright, causing the absolute value of the bank angle θ to decrease, the damping force generated by the variable damping shock absorbers Df and Dr increases as the absolute value of the bank angle θ decreases. This can give the driver a sense of agility when operating the vehicle body B to upright, and can also quickly dampen vibrations of the vehicle body B at the end of the uprighting phase.

[0036] Furthermore, when the vehicle body B is in an upright position, the command generation unit 52 should generate control commands Ff and Fr such that the damping force is increased by decreasing the absolute value of the bank angle θ, while also increasing the extension damping force in the front wheel variable damping shock absorber Df above the compression damping force, and increasing the compression damping force in the rear wheel variable damping shock absorber Dr above the extension damping force. By increasing the extension damping force in the front wheel variable damping shock absorber Df and increasing the compression damping force in the rear wheel variable damping shock absorber Dr, the front wheel variable damping shock absorber Df becomes less likely to extend, and the rear wheel variable damping shock absorber Dr becomes less likely to contract, causing the vehicle body B to tend to tilt forward, making it easier for the driver of the saddle-type vehicle M to operate the vehicle body B to upright.

[0037] As mentioned above, when the vehicle body B is leaning, the command generation unit 52 generates control commands Ff and Fr to increase the damping force of the variable damping shock absorbers Df and Dr according to the absolute value of the bank angle θ, as shown in Figure 6. When the vehicle body B is standing up, as shown in Figure 7, the command generation unit 52 generates control commands Ff and Fr to increase the damping force of the variable damping shock absorbers Df and Dr as the absolute value of the bank angle θ decreases. Therefore, if the calculation formula for determining the control commands Ff and Fr is simply switched when the vehicle body B switches from leaning to standing up, the values ​​of the control commands Ff and Fr will change abruptly. To address this, the command generation unit 52 processes the values ​​of the control commands Ff and Fr to change slowly when the vehicle body B switches from leaning to standing up, mitigating the abrupt change in the values ​​of the control commands Ff and Fr. For example, when the vehicle body B switches from a leaning state to an upright state, the command generation unit 52 may fade out the control commands Ff and Fr obtained using the calculation formula used when the vehicle body B is leaning, and fade in the control commands Ff and Fr obtained using the calculation formula used when the vehicle body B is upright, or it may gradually decrease the values ​​of the control commands Ff and Fr used when the vehicle body B is leaning to change them to the values ​​of the control commands Ff and Fr that should be used when the vehicle body B is upright. In addition, if there is a steady-state turning period in which the bank angular velocity ω becomes 0 between the transition of the vehicle body B from a leaning state to an upright state, the command generation unit 52 will adopt control commands Ff and Fr suitable for the saddle-type vehicle M during steady-state turning. If there is a difference between the values ​​of the control commands Ff and Fr to be used during steady-state turning and the values ​​of the control commands Ff and Fr that have been used or will be used, the command generation unit 52 should mitigate the sudden change in the control commands Ff and Fr as described above.

[0038] Furthermore, if the absolute value of the bank angle θ is small near 0°, and the vehicle body B is hardly tilted and it cannot be recognized as turning, it may be better not to change the control commands Ff and Fr according to the absolute value of the bank angle θ. To address such cases, when the absolute value of the bank angle θ is less than or equal to the bank angle threshold, the command generation unit 52 outputs control commands Ff and Fr suitable for straight-line driving of the saddle-type vehicle M. In this way, even though the saddle-type vehicle M is not turning, the damping coefficients of the variable damping shock absorbers Df and Dr can be maintained at the level suitable for straight-line driving instead of being changed to one suitable for turning, thereby improving the ride comfort of the saddle-type vehicle M.

[0039] Furthermore, if the bank angular velocity ω fluctuates rapidly near zero, causing the vehicle body B to repeatedly lean and straighten, resulting in vibrational changes and hunting of the control commands Ff and Fr, a threshold value for the absolute value of the bank angular velocity ω may be set. If the absolute value of the bank angular velocity ω is less than or equal to the angular velocity threshold, the command generation unit 52 may output the control commands Ff and Fr appropriate for steady-state turning as described above. In this way, if the command generation unit 52 outputs the control commands Ff and Fr during steady-state turning when the absolute value of the bank angular velocity ω is less than or equal to the angular velocity threshold, hunting of the control commands Ff and Fr can be prevented, thereby preventing vibrational changes in the ground contact feel of the saddle-type vehicle M during turning. The command generation unit 52 may also maintain the previous control commands Ff and Fr when the absolute value of the bank angular velocity ω is less than or equal to the angular velocity threshold. In this way, if the absolute value of the bank angular velocity ω is less than or equal to the angular velocity threshold, even if the command generation unit 52 maintains the previous control commands Ff and Fr, it is possible to prevent the control commands Ff and Fr from hunting and to prevent the ground contact sensation of the saddle-type vehicle M during turning from changing vibrationally.

[0040] The correction unit 53 corrects the control commands Ff and Fr based on the travel speed V of the saddle-type vehicle M. Specifically, the correction unit 53 multiplies the control commands Ff and Fr by a speed gain GV corresponding to the travel speed V to generate corrected control commands Ffc and Frc. The speed gain GV is a predetermined gain according to the speed range of the travel speed V, and is set to a value of 1 or greater, changing in steps with respect to the travel speed V, for example, 1 in the speed range of less than 40 km / h, 1.1 in the speed range of 40 km / h or more and less than 60 km / h, and 1.2 in the speed range of 60 km / h or more. The speed gain GV may change proportionally with respect to the travel speed V, or it may change proportionally with respect to

[0041] Therefore, the correction unit 53 determines the speed gain GV according to the travel speed V, multiplies the control commands Ff and Fr by the determined speed gain GV to generate and output corrected control commands Ffc and Frc. Because the correction unit 53 corrects the control commands Ff and Fr to suit the travel speed V according to the travel speed V and generates corrected control commands Ffc and Frc, the damping force variable shock absorbers Df and Dr can exert a damping force suitable for the travel speed V of the saddle-type vehicle M.

[0042] The driver 54 has a drive circuit that supplies current to the actuator 27, and upon receiving the corrected control commands Ffc and Frc obtained as described above, it supplies the current instructed by the corrected control commands Ffc and Frc to the actuator 27. When the corrected control commands Ffc and Frc are input from the correction unit 53 and the driver 55 supplies current to the actuator 27 in this way, the flow path area of ​​the damping force adjustment valve 25 is adjusted and the damping coefficients of the variable damping shock absorbers Df and Dr are controlled.

[0043] Incidentally, as the hardware resources of the suspension control device 1, specifically, for example, although not shown in the drawings, an amplifier for amplifying signals output from an acceleration sensor 6, a bank angular velocity detection unit 3 as a gyro sensor, and a speed detection unit 4, a converter for converting an analog signal into a digital signal, a computer system including a CPU (Central Processing Unit), a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), a crystal oscillator, and a bus line for connecting these may be configured. Then, by executing a program for the CPU to function as the suspension control device 1, each part in the bank angle calculation unit 7 in the bank angle detection unit 2 and the control unit 5 can be realized. Incidentally, since the suspension control device 1 is a well-known computer system, when the saddle-type vehicle M includes an ECU (Electronic Control Unit), it can be integrated into the ECU.

[0044] Here, the processing procedure in the above-described suspension control device 1 will be described based on the flowchart shown in FIG. 8. First, the suspension control device 1 reads the accelerations Gx, Gy, Gz, the bank angular velocity ω, and the traveling speed V detected by the acceleration sensor 6 and the bank angular velocity detection unit 3 (step S1). Subsequently, the suspension control device 1 obtains the bank angle θ (step S2).

[0045] Further, the suspension control device 1 determines whether or not the value θ·ω obtained by multiplying the bank angle θ and the bank angular velocity ω is 0 (step S3). As a result of the determination in step S3, if θ·ω is not 0, since neither the bank angle θ nor the bank angular velocity ω is 0, it is a situation where the vehicle body B is tilted, and the process proceeds to step S4. On the other hand, as a result of the determination in step S3, if θ·ω is 0, since one or both of the bank angle θ and the bank angular velocity ω are 0, the saddle-type vehicle M is traveling straight or is in a steady turn, and the process proceeds to step S11.

[0046] Subsequently, when θ·ω≠0 in the determination of step S3, since the vehicle body B is in a tilted state, in order to determine whether the vehicle body B is in a leaning - down state or a rising - up state, it is determined whether the value θ·ω obtained by multiplying the bank angle θ and the bank angular velocity ω exceeds 0 (step S4). As a result of the determination in step S4, if θ·ω>0, it is determined that the vehicle body B is in a leaning - down state (step S5), and if θ·ω<0, it is determined that the vehicle body B is in a rising - up state (step S6).

[0047] Subsequently, when it is determined that the vehicle body B is in a leaning - down state, control commands Ff and Fr are obtained by multiplying the absolute value of the bank angle θ by the gain G1 (step S7). On the other hand, when it is determined that the vehicle body B is in a rising - up state, Ff(Fr)=A×(|θmax| - |θ|) is calculated to obtain control commands Ff and Fr (step S8). Further, the suspension control device 1 obtains a speed gain GV from the traveling speed V, and multiplies the speed gain GV by the control commands Ff and Fr to obtain corrected control commands Ffc and Frc (step S9).

[0048] Then, the suspension control device 1 supplies current from the driver 54 to the actuator 27 as indicated by the corrected control commands Ffc and Frc to drive the damping - force adjustment valve 25, and controls the damping forces of the variable - damping shock absorbers Df and Dr (step S10).

[0049] Returning, when θ·ω = 0 in the determination of step S3, since the straddle - type vehicle M is traveling straight or in a steady turn, in order to determine which situation it is, it is determined whether the absolute value |θ| of the bank angle θ is 0 (step S11).

[0050] In step S11, if |θ| = 0, the vehicle body B is not tilted and the saddle-type vehicle M is traveling in a straight line, so the system proceeds to step S12, where the suspension control device 1 obtains control commands Ff and Fr suitable for the straight-line travel of the saddle-type vehicle M, and then proceeds to step S10. When the saddle-type vehicle M is traveling in a straight line, in step S10, unlike when turning, the suspension control device 1 supplies current from the driver 54 to the actuator 27 to drive the damping force adjustment valve 25 as instructed by the control commands Ff and Fr suitable for straight-line travel, and controls the damping force of each damping force variable shock absorber Df and Dr.

[0051] On the other hand, if the judgment in step S11 is that |θ|≠0, then although the vehicle body B is tilted, the bank angular velocity ω is 0, and the bank angle θ of the saddle-type vehicle M has not changed, and the saddle-type vehicle M is in steady-state cornering. Therefore, the process proceeds to step S13, where the suspension control device 1 obtains control commands Ff, Fr suitable for steady-state cornering of the saddle-type vehicle M, and then proceeds to step S9. Note that when the saddle-type vehicle M is in steady-state cornering, the driving is stabilized when the variable damping shock absorbers Df, Dr exert a relatively high damping force, whereas when the saddle-type vehicle M is driving straight, the ride comfort can be improved when the variable damping shock absorbers Df, Dr exert a relatively low damping force. For this reason, the damping force generated by the variable damping shock absorbers Df, Dr by the control commands Ff, Fr suitable for steady-state cornering is higher than the damping force generated by the variable damping shock absorbers Df, Dr by the control commands Ff, Fr suitable for straight-line driving. Furthermore, the damping force generated by the variable damping shock absorbers Df and Dr during straight-line driving can be determined by using control laws that prioritize ride comfort or control laws suitable for suppressing vibrations of the vehicle body B, front wheels Wf, and rear wheels Wr during straight-line driving, for example, to obtain control commands Ff and Fr.

[0052] The suspension control device 1 then repeatedly executes the processes from step S1 to step S13 described above to control the damping coefficients of the variable damping shock absorbers Df and Dr.

[0053] As described above, the suspension control device 1 executes the series of processes described above, thereby realizing the processing of each part of the bank angle detection unit 2 and the control unit 5. These parts are realized when the CPU reads the program and executes the calculation processes described above.

[0054] As described above, the suspension control device 1 of this embodiment controls adjustable damping force shock absorbers Df and Dr interposed between the vehicle body B of a saddle-type vehicle M and the front wheels Wf and rear wheels Wr, and comprises a bank angle detection unit 2 that detects the bank angle θ, which is the left-right tilt angle of the vehicle body B; a bank angular velocity detection unit 3 that detects the bank angular velocity ω of the vehicle body B; and a control unit 5 that controls the damping force of the adjustable damping force shock absorbers Df and Dr based on the bank angle θ and bank angular velocity ω.

[0055] With the suspension control device 1 configured in this way, the damping force of the variable damping shock absorbers Df and Dr is controlled based on the bank angle θ and bank angular velocity ω of the vehicle body B. Therefore, it is possible to understand whether the vehicle body B is leaning or straightening and generate damping forces in the variable damping shock absorbers Df and Dr that are suitable not only for when the vehicle body B is leaning but also for when the vehicle body B is straightening. Thus, with the suspension control device 1 of this embodiment, the variable damping shock absorbers Df and Dr can exert damping forces suitable for the banking state of the vehicle body B, thereby improving the sense of ground contact and the agility when the vehicle body B is straightening in a saddle-type vehicle M.

[0056] Furthermore, the control unit 5 in the suspension control device 1 of this embodiment includes a vehicle body condition determination unit 51 that determines whether the vehicle body B is in a leaning state where it is changing in the direction of leaning to the left or right, or in an upright state where it is changing in the direction of straightening, based on the bank angle θ and bank angular velocity ω, and a command generation unit 52 that generates a control command to increase the damping force of the variable damping force shock absorbers Df and Dr when the absolute value of the bank angle θ is large when the vehicle body B is in a leaning state, and generates control commands Ff and Fr to increase the damping force of the variable damping force shock absorbers Df and Dr when the absolute value of the bank angle θ is small when the vehicle body B is in an upright state.

[0057] With the suspension control device 1 configured in this way, when the vehicle body B is leaning, the damping force of the variable damping shock absorbers Df and Dr increases in accordance with the absolute value of the bank angle θ. Therefore, in situations where the vehicle body B leans and the absolute value of the bank angle θ increases after the saddle-type vehicle M begins to turn, the variable damping shock absorbers Df and Dr generate a high damping force, improving the ground contact feel of the front wheels Wf and rear wheels Wr. Furthermore, with the suspension control device 1 configured in this way, when the vehicle body B is standing up, the damping force of the variable damping shock absorbers Df and Dr increases as the absolute value of the bank angle θ decreases. Therefore, in situations where the vehicle body B stands up and the absolute value of the bank angle θ decreases during the latter half of cornering of the saddle-type vehicle M, the damping force generated by the variable damping shock absorbers Df and Dr increases in accordance with the decrease in the absolute value of the bank angle θ, which can give the driver a sense of agility in the operation of standing up the vehicle body B, and can also quickly dampen the vibration of the vehicle body B at the end of the standing-up phase.

[0058] Furthermore, in the control unit 5 of the suspension control device 1 of this embodiment, the command generation unit 52 generates control commands Ff and Fr to increase the extension damping force of the variable damping shock absorber Df interposed between the vehicle body B of the saddle-type vehicle M and the front wheel Wf, and to increase the compression damping force of the variable damping shock absorber Dr interposed between the vehicle body B of the saddle-type vehicle M and the rear wheel Wr, when the vehicle body B of the saddle-type vehicle M is leaning or straightening. With the suspension control device 1 configured in this way, when the vehicle body B of the saddle-type vehicle M is leaning or straightening, the variable damping shock absorber Df on the front wheel side becomes less likely to extend and the variable damping shock absorber Dr on the rear wheel side becomes less likely to contract, so the vehicle body B tends to tilt forward, making it easier for the driver of the saddle-type vehicle M to perform the leaning and straightening operations of the vehicle body B. Furthermore, in order to make it easier to tilt the front of the vehicle body B of the saddle-type vehicle M when it is leaning down and standing up, the command generation unit 52 should generate control commands Ff and Fr such that when the vehicle body B is in a leaning or standing-up state, the extension damping force of the variable damping shock absorber Df interposed between the vehicle body B of the saddle-type vehicle M and the front wheel Wf is higher than the compression damping force, and the compression damping force of the variable damping shock absorber Dr interposed between the vehicle body B of the saddle-type vehicle M and the rear wheel Wr is higher than the extension damping force. With the suspension control device 1 configured in this way, when the extension damping force of the variable damping shock absorber Df on the front wheel side becomes higher than the compression damping force and it repeatedly expands and contracts, the variable damping shock absorber Df gradually contracts, and when the extension damping force of the variable damping shock absorber Dr on the rear wheel side becomes higher than the compression damping force and it repeatedly expands and contracts, the variable damping shock absorber Dr gradually extends, making it easier for the vehicle body B to tilt forward.

[0059] Furthermore, the suspension control device 1 of this embodiment includes a speed detection unit 4 that detects the travel speed V of the saddle-type vehicle M, and the control unit 5 includes a correction unit 53 that corrects the control commands Ff and Fr so as the travel speed V increases, the damping force of the variable damping shock absorbers Df and Dr increases.

[0060] With the suspension control device 1 configured in this way, the control commands Ff and Fr for controlling the variable damping shock absorbers Df and Dr are corrected to increase the damping force according to the travel speed V. As a result, the damping force of the saddle-type vehicle M during cornering becomes suitable for the travel speed V, and the swaying of the vehicle body B during cornering can be suppressed when the travel speed V is high.

[0061] As mentioned above, when the vehicle body B is leaning, the control unit 5 increases the damping force of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ increases, and when the vehicle body B is standing upright, it increases the damping force of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ decreases. In contrast, the command generation unit 52 in the control unit 5 may generate control commands Ff and Fr to increase only the compression damping force of the variable damping shock absorbers Df and Dr when the vehicle body B is leaning, and generate control commands Ff and Fr to increase only the extension damping force of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ decreases when the vehicle body B is standing upright.

[0062] With the suspension control device 1 configured in this way, when the absolute value of the bank angle θ increases when the vehicle body B is leaned over, only the compression damping force of the variable damping shock absorbers Df and Dr is increased. This ensures a sense of contact with the road when the vehicle body B is leaned over, while the extension damping force of the variable damping shock absorbers Df and Dr can be set to a damping force suitable for ride comfort, thereby improving ride comfort in a saddle-type vehicle M.

[0063] Furthermore, with the suspension control device 1 configured in this way, when the absolute value of the bank angle θ when the vehicle body B is upright decreases, only the extension damping force of the variable damping force shock absorbers Df and Dr is increased. This suppresses the lifting of the vehicle body B when it is upright, ensuring a sense of ground contact and agility, while the compression damping force of the variable damping force shock absorbers Df and Dr can be set to a damping force suitable for ride comfort, thereby improving ride comfort in a saddle-type vehicle M.

[0064] Furthermore, as mentioned above, the control unit 5 determines control commands Ff and Fr to control the damping force of the variable damping shock absorbers Df and Dr depending on the magnitude of the absolute value of the bank angle θ when the vehicle body B is leaning down and when it is straightening up. However, when the vehicle body B is leaning down, control commands Ff and Fr may be determined to be proportional to the absolute value of the bank angular velocity ω, and when the vehicle body B is straightening up, control commands Ff and Fr may be determined so that their values ​​decrease as the absolute value of the bank angular velocity ω decreases.

[0065] As mentioned above, the basic operation of the suspension control device 1 was explained using the following examples: when a saddle-type vehicle M transitions from straight-line driving to turning driving with a constant curvature, the vehicle body B tilts relative to the road surface, causing the vehicle body B to lean; and when returning from turning driving to straight-line driving, the vehicle body B straightens up to make its posture perpendicular to the road surface.

[0066] The suspension control device 1 can determine whether the vehicle body B is leaning or straightening and generate a damping force appropriate to the situation at that time. However, to deal with situations where the saddle-type vehicle M is slalom driving on a series of left and right curves, causing the vehicle body B to lean and straighten continuously, or where the turning radius of the saddle-type vehicle M changes midway, causing the vehicle body B to lean multiple times in a row or straighten continuously, the suspension control device 1 should process as follows.

[0067] The following describes in detail the processing of the suspension control device 1 when the vehicle body B is tilted and straightened in succession, and when the vehicle body B is tilted or straightened in succession.

[0068] In this case, the vehicle body condition determination unit 51 in the suspension control device 1 determines, based on the bank angle θ and bank angular velocity ω, whether the vehicle body B is leaning or straightening, and also determines when the leaning of the vehicle body B has finished and when the straightening of the vehicle body B has finished.

[0069] Specifically, the vehicle body condition determination unit 51 should determine that the leaning or straightening of the vehicle body B has finished when the bank angle θ is 0 or the bank angular velocity ω is 0. When the bank angle θ is 0, the vehicle body B is in a vertical upright position. Therefore, the vehicle body condition determination unit 51 determines that the leaning or straightening of the vehicle body B has finished when the bank angle θ becomes 0. The vehicle body condition determination unit 51 may also determine whether the leaning of the vehicle body B has finished or the straightening of the vehicle body B has finished. In that case, if the bank angular velocity ω takes a positive value when the bank angle θ is 0, the vehicle body condition determination unit 51 determines that the straightening of the vehicle body B has finished because the vehicle body B is transitioning from straightening to leaning. Furthermore, if the bank angular velocity ω takes a negative value when the bank angle θ is 0, the vehicle body B is in a state of transition from leaning to straightening, and the vehicle body condition determination unit 51 determines that the leaning of the vehicle body B has finished.

[0070] Furthermore, when the bank angular velocity ω is 0, the vehicle body B is in a constant tilt position at a bank angle θ. Therefore, the vehicle body condition determination unit 51 determines that when the bank angular velocity ω is 0, the leaning or straightening of the vehicle body B has finished. The vehicle body condition determination unit 51 may also determine whether the leaning of the vehicle body B has finished or the straightening of the vehicle body B has finished. If the bank angular velocity ω immediately before the bank angular velocity ω becomes 0 is a positive value and the bank angle θ is a positive value, or if the bank angular velocity ω immediately before the bank angular velocity ω becomes 0 is a negative value and the bank angle θ is a negative value, the leaning of the vehicle body B has finished and the vehicle body B has stopped in a position at a bank angle θ, so the vehicle body condition determination unit 51 determines that the leaning of the vehicle body B has finished. If the bank angular velocity ω is positive and the bank angle θ is negative just before the bank angular velocity ω becomes 0, or if the bank angular velocity ω is negative and the bank angle θ is positive just before the bank angular velocity ω becomes 0, the vehicle body B has finished standing up and has stopped in a position where the bank angle θ is reached. Therefore, the vehicle body condition determination unit 51 determines that the standing up of the vehicle body B has finished.

[0071] In this way, the vehicle body condition determination unit 51 can determine, based on the bank angle θ and bank angular velocity ω, whether the vehicle body B is leaning or straightening up, as well as whether the leaning or straightening of the vehicle body B has ended.

[0072] As described above, the command generation unit 52 in the suspension control device 1 generates control commands Ff and Fr that increase the damping force of the variable damping shock absorbers Df and Dr as the absolute value of the bank angle θ increases when the vehicle body B is in a leaning state where it is leaning in the direction of leaning, and generates control commands Ff and Fr that increase the damping force of the variable damping shock absorbers Df and Dr as the absolute value of the bank angle θ decreases when the vehicle body B is in an upright state where it is upright.

[0073] In addition to the processing described above, the command generation unit 52 maintains the previously outputted control commands Ff and Fr until a certain period of time has elapsed when the vehicle body condition determination unit 51 determines that the leaning or straightening of the vehicle body B has finished. The command generation unit 52 generates control commands Ff and Fr so that the damping force is gradually increased as the vehicle body condition determination unit 51 leans or straightens the vehicle body B. When the leaning or straightening of the vehicle body B is finished, the command generation unit 52 maintains the previous control commands Ff and Fr until a certain period of time has elapsed to maintain a state of high damping force. When a certain period of time has elapsed without the vehicle body B leaning or straightening, the command generation unit 52 generates control commands Ff and Fr to decrease the damping force. When the vehicle body B is leaning, the command generation unit 52 generates control commands Ff and Fr by multiplying the bank angle θ by the gain G1. As shown in Figure 10, the control commands Ff and Fr are increased until the leaning state of the vehicle body B is completed. Once the leaning state of the vehicle body B is completed, the values ​​of the control commands Ff and Fr that were output at the time of completion are maintained for a certain period of time, after which the control commands Ff and Fr are decreased. Also, when the vehicle body B is standing up, the command generation unit 52 generates control commands Ff and Fr by calculating the formula Ff(Fr) = A × (|θmax| - |θ|). As shown in Figure 10, the control commands Ff and Fr are increased until the standing state of the vehicle body B is completed. Once the standing state of the vehicle body B is completed, the values ​​of the control commands Ff and Fr that were output at the time of completion are maintained for a certain period of time, after which the control commands Ff and Fr are decreased. Furthermore, measures may be taken to mitigate sudden changes in the control commands Ff and Fr at the start of tilting or righting.

[0074] Furthermore, if the vehicle body B is leaned further before a certain amount of time has elapsed since the vehicle body condition determination unit 51 has finished leaning the vehicle body B, the absolute value of the bank angle θ will increase. Therefore, the command generation unit 52 multiplies the absolute value of the bank angle θ by the gain G1 to generate control commands Ff and Fr that instruct the current to be supplied to the actuators 27 in the damping force adjustment valves 25 of each damping force variable shock absorber Df and Dr. In other words, if the vehicle body B continues to lean after the completion of the leaning of the vehicle body B, the command generation unit 52 maintains the control commands Ff and Fr at the end of the leaning of the vehicle body B. However, if the vehicle body B leans again without waiting for a certain amount of time, the command generation unit 52 obtains control commands Ff and Fr by multiplying the increased absolute value of the bank angle θ by the gain G1. Therefore, as shown in Figure 11, the command generation unit 52 increases the control commands Ff and Fr in accordance with the increase in the absolute value of the bank angle θ due to the leaning of the vehicle B, maintains the control commands Ff and Fr at the end when the leaning of the vehicle B is completed, and further increases the control commands Ff and Fr in accordance with the increase in the absolute value of the bank angle θ as the leaning is resumed without a certain amount of time having elapsed.

[0075] The command generation unit 52 calculates the formula Ff(Fr) = A × (|θmax| - |θ|) if the vehicle body B rises again before a certain amount of time has elapsed since the vehicle body condition determination unit 51 has finished rising, because the absolute value of the bank angle θ becomes smaller, and generates control commands Ff, Fr that instruct the current to be supplied to the actuator 27 in the damping force adjustment valve 25 of each damping force variable shock absorber Df, Dr. In other words, if the vehicle body B continues to rise after it has finished rising, the command generation unit 52 maintains the control commands Ff, Fr at the end of the rising as the vehicle body B finishes rising. However, if the vehicle body B rises again without waiting for a certain amount of time, the command generation unit 52 calculates the control commands Ff, Fr by substituting the decreasing absolute value of the bank angle θ into the above formula. Therefore, as shown in Figure 11, the command generation unit 52 increases the control commands Ff and Fr in accordance with the decrease in the absolute value of the bank angle θ as the vehicle B stands up, maintains the control commands Ff and Fr at the end when the standing up of the vehicle body B is completed, and further increases the control commands Ff and Fr in accordance with the decrease in the absolute value of the bank angle θ as the standing up resumes without a certain amount of time having elapsed.

[0076] The aforementioned fixed time can be set arbitrarily. The command generation unit 52 may change the fixed time for maintaining the control commands Ff and Fr according to the travel speed V of the saddle-type vehicle M detected by the speed detection unit 4. When the travel speed V increases, increasing the predetermined time will increase the time during which the damping force is maintained at a high level after the leaning and straightening of the vehicle body B is completed, thereby stabilizing the posture of the vehicle body B. For this reason, the command generation unit 52 will stabilize the posture of the vehicle body B by increasing the fixed time in proportion to the travel speed V, or by gradually increasing the fixed time in response to the increase in travel speed V.

[0077] Furthermore, the command generation unit 52 determines that the saddle-type vehicle M is performing slalom driving when the vehicle body condition determination unit 51 determines that the vehicle body B is tilting and straightening alternately in succession, and generates control commands Ff and Fr suitable for slalom driving. The command generation unit 52 determines that the saddle-type vehicle M is performing slalom driving if the other tilting and straightening of the vehicle body B occurs within a predetermined time after the completion of one of the tilting and straightening of the vehicle body B.

[0078] The command generation unit 52, when the vehicle body condition determination unit 51 determines that the vehicle body B is performing slalom driving in which it alternates between leaning and straightening, generates control commands Ff and Fr that generate a damping force at least equal to or greater than the damping force at the end of leaning during the straightening operation following the completion of leaning of the vehicle body B, and generates control commands Ff and Fr that generate a damping force at least equal to or greater than the damping force at the end of straightening during the leaning operation following the completion of straightening of the vehicle body B. In other words, the command generation unit 52 generates control commands Ff and Fr in a manner that does not reduce the damping force during slalom driving. Note that not reducing the damping force includes increasing or maintaining the damping force.

[0079] More specifically, the command generation unit 52 maintains the damping force at the end of the leaning of the vehicle body B for a predetermined time after the vehicle body condition determination unit 51 has finished leaning the vehicle body B. If the vehicle body B starts to straighten up during this predetermined time, the command generation unit 52 generates control commands Ff and Fr so as not to reduce the damping force at the end of the leaning of the vehicle body B until the vehicle body B has finished straightening up.

[0080] The command generation unit 52 maintains the damping force at the end of the vehicle body B's uprighting position for a predetermined time after the vehicle body condition determination unit 51 has finished righting the vehicle body B. If the vehicle body B starts to lean during this predetermined time, the command generation unit 52 generates control commands Ff and Fr to prevent the damping force at the end of the vehicle body B's uprighting position from decreasing until the leaning of the vehicle body B is completed.

[0081] Furthermore, the command generation unit 52 generates control commands Ff and Fr based on the maximum absolute value of the bank angle θ generated by the leaning of the vehicle body B during slalom driving.

[0082] Therefore, as shown in Figure 12, the command generation unit 52 generates control commands Ff and Fr during slalom driving based on the maximum absolute value of the bank angle θ generated by the leaning of the vehicle body B during slalom driving. When the absolute value of the bank angle θ is updated to a larger value, the command generation unit 52 generates control commands Ff and Fr based on the updated absolute value of the bank angle θ.

[0083] As mentioned above, the command generation unit 52 determines that slalom driving is in progress if the other tilting or straightening of the vehicle body B occurs within a predetermined time after the completion of one of the tilting or straightening of the vehicle body B, and generates control commands Ff and Fr suitable for slalom driving. However, when a saddle-type vehicle M is driving in a slalom, the bank angle θ crosses 0° and switches from a positive value to a negative value or from a negative value to a positive value, so the change in the value of the bank angle θ exhibits such a switch may also be used as a condition for determining whether or not slalom driving is in progress.

[0084] The predetermined time can be set arbitrarily. Furthermore, the predetermined time for determining slalom driving after the uprighting phase is complete and the predetermined time for determining slalom driving after the leaning phase are complete may be different. The predetermined time may be different from, or it may be set to be the same as, the constant time for maintaining the damping force as described above.

[0085] As mentioned above, when the vehicle body B is leaning, the control unit 5 increases the damping force of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ increases, and when the vehicle body B is standing upright, it increases the damping force of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ decreases. In contrast, the command generation unit 52 in the control unit 5 may generate control commands Ff and Fr to increase only the compression damping force of the variable damping shock absorbers Df and Dr when the vehicle body B is leaning, and generate control commands Ff and Fr to increase only the extension damping force of the variable damping shock absorbers Df and Dr when the absolute value of the bank angle θ decreases when the vehicle body B is standing upright.

[0086] With the suspension control device 1 configured in this way, when the absolute value of the bank angle θ increases when the vehicle body B is leaned over, only the compression damping force of the variable damping shock absorbers Df and Dr is increased. This ensures a sense of contact with the road when the vehicle body B is leaned over, while the extension damping force of the variable damping shock absorbers Df and Dr can be set to a damping force suitable for ride comfort, thereby improving ride comfort in a saddle-type vehicle M.

[0087] Furthermore, with the suspension control device 1 configured in this way, when the absolute value of the bank angle θ when the vehicle body B is upright decreases, only the extension damping force of the variable damping force shock absorbers Df and Dr is increased. This suppresses the lifting of the vehicle body B when it is upright, ensuring a sense of ground contact and agility, while the compression damping force of the variable damping force shock absorbers Df and Dr can be set to a damping force suitable for ride comfort, thereby improving ride comfort in a saddle-type vehicle M.

[0088] Furthermore, as mentioned above, the control unit 5 determines control commands Ff and Fr to control the damping force of the variable damping shock absorbers Df and Dr depending on the magnitude of the absolute value of the bank angle θ when the vehicle body B is leaning down and when it is straightening up. However, when the vehicle body B is leaning down, control commands Ff and Fr may be determined to be proportional to the absolute value of the bank angular velocity ω, and when the vehicle body B is straightening up, control commands Ff and Fr may be determined so that their values ​​decrease as the absolute value of the bank angular velocity ω decreases.

[0089] The processing procedures in the suspension control device 1 for cases where the vehicle body B leans and straightens continuously, and when the vehicle body B leans or straightens continuously, will be explained based on the flowchart shown in Figure 13. First, the suspension control device 1 generates control commands Ff and Fr suitable for straight driving or steady cornering, and performs normal processing by supplying the current instructed by the control commands Ff and Fr to the actuator 27 (step S101). In normal processing, the vehicle body B does not lean or straighten, and the vehicle body B is either tilted or the vehicle body B is performing steady cornering while maintaining a constant bank angle, so the suspension control device 1 generates control commands Ff and Fr to generate predetermined damping forces in the variable damping shock absorbers Df and Dr. Furthermore, when the saddle-type vehicle M is performing a steady turn, the driving becomes stable when the variable damping shock absorbers Df and Dr exert relatively high damping force, whereas when the saddle-type vehicle M is driving straight, the ride comfort can be improved when the variable damping shock absorbers Df and Dr exert relatively low damping force. Therefore, in normal processing, if the absolute value of the bank angle θ is 0, control Ff and Fr suitable for straight driving may be generated, and if the absolute value of the bank angle θ is not 0, control commands Ff and Fr suitable for steady turn may be generated.

[0090] Next, the suspension control device 1 determines whether the value θ・ω, obtained by multiplying the bank angle θ by the bank angular velocity ω, is a positive value (step S102). If the result of the determination in step S102 is that the value θ・ω is a positive value, then the bank angle θ is a positive value and the bank angular velocity ω is also a positive value, or the bank angle θ is a negative value and the bank angular velocity ω is also a negative value, and the vehicle body B is in a leaned position, so the device proceeds to step S103. On the other hand, if the result of the determination in step S102 is that the value θ・ω is not a positive value, the device proceeds to step S110.

[0091] In step S103, since the vehicle body B is leaning, the suspension control device 1 performs the processing for when the vehicle body B is leaning, multiplying the absolute value of the bank angle θ by the gain G1 to generate control commands Ff and Fr, and multiplying the speed gain GV by the control commands Ff and Fr to obtain corrected control commands Ffc and Frc.

[0092] Subsequently, the suspension control device 1 proceeds to step S104, where it supplies current to the actuator 27 as instructed by the corrected control commands Ffc and Frc, drives the damping force adjustment valve 25, and controls the damping force of each variable damping shock absorber Df and Dr.

[0093] Next, the suspension control device 1 determines whether the leaning of the vehicle body B is complete (step S105). Specifically, in step S105, the suspension control device 1 determines whether the value θ・ω is 0.

[0094] If the value θ・ω is not 0, the leaning of the vehicle body B is not yet complete, and the vehicle body B is still in a leaning state. Therefore, the suspension control device 1 returns to the process in step S103 and repeats the leaning process.

[0095] On the other hand, if the value θ・ω is not 0, the tilting of the vehicle body B is complete, so the suspension control device 1 proceeds to the process in step S106 and supplies current to the actuator 27 as instructed by the corrected control commands Ffc and Frc obtained in step S103, maintaining the damping force of each damping force variable shock absorber Df and Dr at the same level as when the tilting was completed.

[0096] Furthermore, the suspension control device 1 proceeds to step S107 to determine whether the value θ・ω has become 0. In other words, the suspension control device 1 determines whether the vehicle body B is in steady-state cornering. If the value θ・ω is 0 and the vehicle body B is in steady-state cornering, the suspension control device 1 proceeds to step S108 to determine whether the time T that has elapsed since the execution of step S106 has become greater than or equal to time Ta.

[0097] If, as a result of the determination in step S108, time T is greater than or equal to time Ta, then time Ta has elapsed since the leaning of the vehicle body B was completed, and the suspension control device 1 proceeds to the process in step S101 to perform normal processing. In the flowchart shown in Figure 13, both the time required to maintain the damping force after the completion of leaning or straightening and the predetermined time required to determine slalom driving are set to the same length of time Ta.

[0098] On the other hand, if the result of the determination in step S108 is that time T is less than time Ta, then time Ta has not elapsed since the leaning of the vehicle body B was completed, so the suspension control device 1 returns to the process of maintaining the damping force in step S106.

[0099] Furthermore, if the value θ・ω becomes a positive or negative value in step S107, the suspension control device 1 proceeds to step S109. If the value θ・ω is a positive or negative value other than 0 in step S107, it means that the vehicle body B has either tilted or straightened up before time Ta has elapsed since the vehicle body B finished tilting. Therefore, in step S109, the suspension control device 1 determines whether the value θ・ω is negative in order to determine whether the vehicle body B has tilted or straightened up.

[0100] If the value θ・ω is negative, the vehicle body B is standing up, so the suspension control device 1 proceeds to step S111. On the other hand, if the value θ・ω is positive, the vehicle body B is leaning down again, so the suspension control device 1 proceeds to step S103, the leaning down process.

[0101] As a result of the determination in step S102, the suspension control device 1 proceeds to the process in step S110, and if the value θ・ω is not a positive value, it determines whether the value θ・ω is a negative value.

[0102] If the value θ・ω is 0 as a result of the processing in step S110, the vehicle body B is either traveling in a straight line or making a steady turn, so the suspension control device 1 proceeds to the processing in step S101 to perform normal processing. On the other hand, if the value θ・ω is a negative value as a result of the processing in step S110, the vehicle body B is in an upright position, so the suspension control device 1 proceeds to step S111 to perform the processing for when the vehicle body B is upright, calculates Ff(Fr) = A × (|θmax| - |θ|) to generate control commands Ff and Fr, and multiplies the speed gain GV by the control commands Ff and Fr to obtain corrected control commands Ffc and Frc.

[0103] Subsequently, the suspension control device 1 proceeds to step S112, where it supplies current to the actuator 27 as instructed by the corrected control commands Ffc and Frc, drives the damping force adjustment valve 25, and controls the damping force of each variable damping shock absorber Df and Dr.

[0104] Next, the suspension control device 1 determines whether the vehicle body B has finished standing up (step S113). Specifically, in step S113, the suspension control device 1 determines whether the value θ・ω is 0.

[0105] If the value θ・ω is not 0, the vehicle body B has not finished standing up and is still in the standing position, so the suspension control device 1 returns to the process of step S111 and repeats the process of leaning down.

[0106] On the other hand, if θ・ω is not 0, the vehicle body B has finished standing up, so the suspension control device 1 proceeds to step S114 and supplies current to the actuator 27 as instructed by the corrected control commands Ffc and Frc obtained in step S113, maintaining the damping force of each damping force variable shock absorber Df and Dr at the same level as when the standing up was completed.

[0107] Furthermore, the suspension control device 1 proceeds to step S115 to determine whether the value θ・ω has become 0. In other words, the suspension control device 1 determines whether the vehicle body B is traveling in a straight line or in a steady turn. If the value θ・ω is 0 and the vehicle body B is traveling in a straight line or in a steady turn, the suspension control device 1 proceeds to step S116 to determine whether the time T that has elapsed since the execution of step S113 is equal to or greater than time Ta.

[0108] If, as a result of the determination in step S116, time T is greater than or equal to time Ta, then time Ta has elapsed since the vehicle body B finished standing up, and the suspension control device 1 proceeds to the process in step S101 to perform normal processing.

[0109] On the other hand, if the result of the determination in step S116 is that time T is less than time Ta, then time Ta has not elapsed since the vehicle body B has finished standing up, so the suspension control device 1 returns to the process of maintaining the damping force in step S114.

[0110] Furthermore, if θ・ω becomes a positive or negative value during step S115, the suspension control device 1 proceeds to step S117. If the value θ・ω is a positive or negative value other than 0 during step S115, it means that the vehicle body B has tilted or straightened up before time Ta has elapsed since the vehicle body B has finished straightening up. Therefore, in step S117, the suspension control device 1 determines whether the value θ・ω is positive or negative in order to determine whether the vehicle body B has tilted or straightened up.

[0111] If the value θ・ω is positive, the vehicle body B is tilted, so the suspension control device 1 proceeds to step S103. On the other hand, if the value θ・ω is negative, the vehicle body B is straightened up again, so the suspension control device 1 proceeds to step S110, the process for when the vehicle straightens up.

[0112] In this manner, the suspension control device 1 repeatedly executes the processes from step S101 to step S117 described above to control the damping coefficients of the variable damping shock absorbers Df and Dr.

[0113] The suspension control device 1 performs the series of processes described above, thereby realizing the processing of each part of the bank angle detection unit 2 and the control unit 5 in the case where the vehicle body B is tilted and straightened in succession, and in the case where the vehicle body B is tilted or straightened in succession. Each part of the suspension control device 1 is realized when the CPU reads the program and executes the processing.

[0114] Furthermore, when using floating-point arithmetic in the aforementioned processes to determine ω・θ = 0 or |θ| = 0, it should be understood that, because information loss or calculation errors may occur, the determination is not made using strict equality signs, but rather involves setting an error range when determining ω・θ = 0 or |θ| = 0. Similarly, it should be understood that the determination of inequalities in the aforementioned processes may also involve setting an error range.

[0115] As described above, the command generation unit 52 in the suspension control device 1 maintains the control command at the end of the leaning or straightening of the vehicle body B for a time Ta without reducing it once the leaning or straightening of the vehicle body B is completed. With the suspension control device 1 configured in this way, after the leaning or straightening of the vehicle body B is completed, the control commands Ff and Fr at the end of the leaning or straightening of the vehicle body B are maintained for a time Ta, so the damping force does not immediately decrease after the leaning or straightening of the vehicle body B is completed, preventing the vehicle body B from swaying and stabilizing its posture.

[0116] Furthermore, the command generation unit 52 in the suspension control device 1 may generate control commands Ff and Fr to further increase the damping force of the variable damping shock absorbers Df and Dr if the vehicle body B continues to be tilted after the vehicle body B has finished tilting, and may generate control commands Ff and Fr to further increase the damping force of the variable damping shock absorbers FDf and Dr if the vehicle body B continues to stand up after the vehicle body B has finished standing up.

[0117] With the suspension control device 1 configured in this way, when the vehicle body B is leaning or straightening up in succession, the damping force of the variable damping shock absorbers Df and Dr is increased, so that the damping force does not decrease between leaning and straightening, and the posture of the vehicle body B remains stable between leaning and straightening, and a good feeling of contact with the front wheels Wf and rear wheels Wr is obtained when leaning after leaning, and the driver's operation of straightening the vehicle body B can be made to feel lighter when straightening after straightening, and vibrations of the vehicle body B at the end of straightening can be stopped early.

[0118] Furthermore, the command generation unit 52 in the suspension control device 1 may generate control commands Ff and Fr that generate a damping force greater than or equal to the damping force at the end of the leaning of the vehicle body B if the vehicle body B starts to straighten up within time Ta after the leaning of the vehicle body B is completed, until the straightening is completed. Alternatively, if the vehicle body B starts to lean again within time Ta after the straightening of the vehicle body B is completed, the command generation unit 52 may generate control commands Ff and Fr that generate a damping force greater than or equal to the damping force at the end of the straightening of the vehicle body B until the leaning is completed.

[0119] With the suspension control device 1 configured in this way, when the vehicle body B is tilted or straightened up in succession, the damping force of the variable damping shock absorbers Df and Dr is increased. Therefore, when the vehicle body B straightens up after the tilting of the vehicle body B has finished, or when the vehicle body B straightens up after the straightening of the vehicle body B has finished, the damping force does not decrease between the tilting and straightening of the vehicle body B. The posture of the vehicle body B remains stable between the tilting and straightening, or between the straightening and tilting. Even when the saddle-type vehicle M performs slalom driving in which the tilting and straightening of the vehicle body B occur alternately in succession, the posture of the vehicle body B remains stable, a good sense of contact between the front wheels Wf and rear wheels Wr is obtained, and the driver's operation of straightening the vehicle body B can be made to feel light and agile.

[0120] Furthermore, the command generation unit 52 in the suspension control device 1 may generate control commands Ff and Fr that do not reduce the damping force of the variable damping shock absorbers Df and Dr when the vehicle body B repeatedly moves between leaning and straightening positions.

[0121] With the suspension control device 1 configured in this way, even when the saddle-type vehicle M performs slalom driving in which the vehicle body B is repeatedly tilted and straightened, the damping force does not decrease during slalom driving, so the posture of the vehicle body B remains stable and a good sense of contact between the front wheels Wf and the rear wheels Wr can be obtained.

[0122] Furthermore, if the vehicle body B repeatedly switches between leaning and straightening, the command generation unit 52 in the suspension control device 1 may generate control commands Ff and Fr based on the maximum absolute value of the bank angle θ due to the leaning of the vehicle body B.

[0123] With the suspension control device 1 configured in this way, when a saddle-type vehicle M performs slalom driving in which the vehicle body B is repeatedly tilted and straightened, control commands Ff and Fr are generated based on the maximum absolute value of the bank angle θ of the vehicle body B during slalom driving. As a result, even if the turning radius of the saddle-type vehicle M changes during slalom driving, the posture of the vehicle body B remains stable, and a good sense of contact between the front wheels Wf and rear wheels Wr can be obtained.

[0124] Furthermore, the suspension control device 1 includes a speed detection unit 4 that detects the travel speed of the saddle-type vehicle M, and the command generation unit 52 may change the fixed time for which control commands Ff and Fr are maintained according to the travel speed V.

[0125] With the suspension control device 1 configured in this way, by changing the constant time according to the driving speed V, the constant time for maintaining damping force can be optimized with respect to the driving speed V. At low speeds, the constant time for maintaining damping force can be shortened, allowing for a quick return to normal control that improves ride comfort once the posture of the vehicle body B becomes stable. At high speeds, the constant time for maintaining damping force can be lengthened, allowing for stable posture of the vehicle body B even at high speeds.

[0126] Furthermore, the suspension control device 1 includes a speed detection unit 4 that detects the travel speed of the saddle-type vehicle M, and the command generation unit 52 may change a predetermined time according to the travel speed V.

[0127] With the suspension control device 1 configured in this way, by changing a predetermined time according to the driving speed V, the predetermined time used for determining slalom driving can be optimized according to the driving speed V. When driving at low speeds, the predetermined time during which the damping force is not reduced is shortened, allowing for a quick return to normal control that improves ride comfort once the posture of the vehicle body B becomes constant. At high speeds, the predetermined time during which the damping force is not reduced is lengthened, allowing for stability of the posture of the vehicle body B even at high speeds.

[0128] This concludes the description of embodiments of the present invention, but the scope of the present invention is not limited to the details shown or described.

[0129] 1...Suspension control device, 2...Bank angle detection unit, 3...Bank angle speed detection unit, 4...Speed ​​detection unit, 5...Control unit, B...Vehicle body, Df...Front wheel damping force variable shock absorber, Dr...Rear wheel shock absorber, M...Saddle-type vehicle, Wf...Front wheel, Wr...Rear wheel

Claims

1. A suspension control device for controlling a variable damping shock absorber, which is interposed between the body and wheels of a saddle-type vehicle and whose damping force can be adjusted, comprising: a bank angle detection unit for detecting the bank angle, which is the left-right tilt angle of the vehicle body; a bank angular velocity detection unit for detecting the bank angular velocity of the vehicle body; and a control unit for controlling the damping force of the variable damping shock absorber based on the bank angle and the bank angular velocity.

2. A suspension control device according to claim 1, wherein the control unit includes a vehicle body condition determination unit that determines whether the vehicle body is in a leaning state where it is changing in the direction of leaning to the left or right, or in an upright state where it is changing in the direction of standing up, based on the bank angle and the bank angular velocity, and a command generation unit that generates a control command to increase the damping force of the variable damping shock absorber when the absolute value of the bank angle is large when the vehicle body is in a leaning state, and generates a control command to increase the damping force of the variable damping shock absorber when the absolute value of the bank angle is small when the vehicle body is in an upright state.

3. A suspension control device according to claim 1, wherein the control unit includes a vehicle body condition determination unit that determines whether the vehicle body is in a leaning state where it is leaning in the left-right direction, or in an upright state where it is changing in the upright direction, based on the bank angle and the bank angular velocity, and a command generation unit that generates a control command to increase only the compression damping force of the variable damping shock absorber when the absolute value of the bank angle is large, and generates a control command to increase only the extension damping force of the variable damping shock absorber when the absolute value of the bank angle is small, when the vehicle body is in an upright state.

4. A suspension control device according to claim 1, wherein the control unit includes a vehicle body condition determination unit that determines whether the vehicle body is in a leaning state, where it is changing in the direction of leaning in the left-right direction, or in an upright state, where it is changing in the direction of standing up, based on the bank angle and the bank angular velocity; and a command generation unit that generates a control command to make the extension damping force of a variable damping shock absorber interposed between the vehicle body and the front wheel of the saddle-type vehicle higher than the compression damping force, and to make the compression damping force of a variable damping shock absorber interposed between the vehicle body and the rear wheel of the saddle-type vehicle higher than the extension damping force.

5. A suspension control device according to any one of claims 2 to 4, comprising a speed detection unit for detecting the travel speed of the saddle-type vehicle, wherein the control unit has a correction unit for correcting the control command so as the travel speed increases, the damping force of the variable damping shock absorber increases.

6. A suspension control device according to any one of claims 2 to 4, wherein the command generation unit maintains the control command at the time the vehicle body is tilted or straightened for a certain period of time after the vehicle body is finished tilting or straightening.

7. A suspension control device according to any one of claims 2 to 4, wherein the command generation unit generates a control command to further increase the damping force of the variable damping shock absorber when the vehicle body continues to be in a tilted state after the end of the tilting of the vehicle body, and generates a control command to further increase the damping force of the variable damping shock absorber when the vehicle body continues to be in an upright state after the end of the uprighting of the vehicle body.

8. A suspension control device according to any one of claims 2 to 4, wherein the command generation unit generates a control command that generates a damping force greater than or equal to the damping force at the end of the vehicle body tilting if the vehicle body starts to stand up within a predetermined time after the vehicle body has finished tilting, until the standing up is completed, and generates a control command that generates a damping force greater than or equal to the damping force at the end of the vehicle body standing up if the vehicle body starts to tilt again within a predetermined time after the standing up is completed.

9. A suspension control device according to any one of claims 2 to 4, wherein the command generation unit generates a control command that does not reduce the damping force of the variable damping shock absorber when the vehicle body repeatedly moves between a leaning state and an upright state.

10. A suspension control device according to any one of claims 2 to 4, wherein the command generation unit generates a control command based on the maximum absolute value of the bank angle due to the leaning of the vehicle body when the vehicle body repeatedly moves between a leaning state and an upright state.

11. A suspension control device according to claim 6, comprising a speed detection unit for detecting the travel speed of the saddle-type vehicle, wherein the command generation unit changes the constant time for which the control command is maintained according to the travel speed.

12. A suspension control device according to claim 8, comprising a speed detection unit for detecting the travel speed of the saddle-type vehicle, wherein the command generation unit changes the predetermined time according to the travel speed.

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