JP3517942B2 - Cab attitude control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the attitude of a cab in a cab-suspended vehicle in which the cab is supported on a vehicle frame by a hydraulic actuator, and more particularly, to changing control parameters. The present invention relates to a cabin posture control device in which a control parameter is gradually changed by a constant value every control cycle. 2. Description of the Related Art In a cab attitude control apparatus disclosed in Japanese Patent Application No. 5-345223 filed by the present applicant, a control parameter change is set to be completed in a predetermined control cycle. If the change amount of the control parameter is extremely large, 1
There is a problem that the amount of change in the control cycle becomes large and a sudden change in the behavior of the cab cannot be sufficiently prevented. [0003] In view of the above-mentioned problems, an object of the present invention is to provide a control system which is capable of controlling a control parameter regardless of the amount of change.
The change amount of the control parameter per one control cycle is fixed to a constant value, the change in the behavior of the cab when changing the control parameter is always within a predetermined range, and the sudden change in the behavior of the cab immediately after the change of the control parameter is determined. An object of the present invention is to provide a cabin attitude control device for preventing such a situation. [0004] In order to achieve the above object, a construction of the present invention comprises a hydraulic actuator for supporting four points of the left, right, front and rear of the cab on a vehicle frame, a wheel supporting portion of the vehicle frame and a vehicle frame. Relative displacement calculating means for calculating a relative displacement in each mode of roll, pitch, and bounce from a vehicle height sensor disposed on the cap support portion and a vehicle height change amount with respect to the road surface detected by the vehicle height sensor. When,
From the power spectrum density of the relative displacement amount of each mode of the cab, the power spectrum density of the displacement amount of each mode of the road surface input is obtained, and the control parameter is obtained from the area ratio of each frequency region obtained by dividing the frequency characteristic diagram at a predetermined frequency. Control parameter calculation means for obtaining the control parameter, control parameter change means for making the control parameter change amount per control cycle constant, and gradually changing to a new control parameter in a plurality of control cycles, It is preferable that the hydraulic control apparatus further includes a cap control amount calculating means for obtaining a control force for suppressing the displacement amount of each mode of the cab, and an electromagnetic oil amount control valve for generating a control force for suppressing the displacement amount of each mode of the cab to each of the hydraulic actuators. Features. According to the present invention, when a change command is issued from an occupant,
New control parameters nk1 to
nk9 is calculated, and the attitude control of the cab is performed using the new control parameters. That is, the relative displacement amount in the roll, pitch, and bounce modes with respect to the road surface is obtained from the vehicle height change amount by the relative displacement amount calculating means. The power parameter density of each mode of road surface input is obtained from the power spectrum density of the relative displacement of each mode of the cab at predetermined time intervals by the control parameter calculating means, and the frequency characteristic diagram thereof is plotted in a predetermined manner. An area ratio of each frequency region divided by frequency is obtained, and a control parameter is obtained from each area ratio. Next, the control parameter gradual change means 1
The control parameter is adjusted by a predetermined value in each control cycle, and is changed to a new control parameter in a plurality of control cycles. Using each control parameter adjusted in each control cycle, a control amount (force) for suppressing displacement of each mode of the cab is obtained by a control amount calculating means,
The control amount is applied to each hydraulic actuator. FIG. 1 is a hydraulic circuit diagram of an apparatus for controlling the attitude of a cab according to the present invention. Hydraulic pump 4 driven by engine
Sucks oil from the oil tank 2 and supplies the oil from the pipe 5 to the accumulator 8 of the pipe 7 via the check valve 6. In order to keep the oil pressure to the pipe 7 at a predetermined value, oil pressure holding means A is provided. That is, tube 5
When the detection value of the oil pressure sensor 9 for detecting the oil pressure of the oil tank exceeds a predetermined value, the oil pressure control valve 12 is switched, and a part of the oil pressure of the pipe 5 passes through the pipe 10, the oil pressure control valve 12, the pipe 13, and the filter 27. It is returned to the oil tank 2. When the oil pressure at the discharge port of the hydraulic pump 4 becomes abnormally high, a part of the pressure oil in the pipe 5 is returned to the oil tank 2 via the known relief valve 26, the pipe 13, and the filter 27. The pressurized oil in the pipe 7 is supplied to hydraulic actuators 19 supporting the front, rear, left and right portions of the cabinet 3 on the vehicle frame 25, respectively. The hydraulic actuator 19 is a cylinder 23
, A rod 24 projecting upward from the piston 22 is connected to the cab 3 by a ball joint or the like, and a cylinder 23 is connected to the vehicle frame 25 by a spherical bearing or the like. Cylinder 2 partitioned by piston 22
The upper and lower chambers 3 are communicated by a throttle passage provided in the piston 22. The suspension mechanism of the vehicle frame includes an axle or suspension member 30 for supporting the wheels 20 on the vehicle frame 25 and a known hydraulic shock absorber 29.
Supported by The hydraulic shock absorber 29 is formed by inserting a piston into a cylinder. The cylinder is connected to a suspension member 30, and a rod projecting upward from the piston is connected to a vehicle frame 25. The coil spring 21 is interposed between the cylinder and the vehicle frame 25. Instead of the coil spring 21, the suspension member 30 may be supported on the vehicle frame 25 by a known leaf spring. Cab 3
Height sensor 2 for detecting the relative displacement of the vehicle with respect to the vehicle frame 25
8 and a vehicle height sensor 31 for detecting the relative displacement of the vehicle frame 25 with respect to the suspension member 30 are provided. The pressure oil in the pipe 7 is supplied to a check valve 14, an oil amount control valve 1 comprising a general neutral position closed type electromagnetic proportional pressure control valve.
6. The air is supplied to the air spring or the accumulator 18 via the throttle 18a, and further supplied to the lower end chamber of the cylinder 23 of the hydraulic actuator 19. The oil pressure supplied to the lower end chamber of the cylinder 23 is detected by the oil pressure sensor 17. When the oil amount control valve 16 is switched, the oil in the lower end chamber of the cylinder 23 is returned to the oil tank 2 via the oil amount control valve 16, the check valve 15, the pipe 13, and the filter 27. The hydraulic actuators 19 on the front, rear, left and right sides of the cabinet 3 are independently provided with check valves 14 and 15, an oil amount control valve 16,
A throttle 18a, a pressure accumulator 18, a hydraulic sensor 17, and a vehicle height sensor 28 are provided. Although not shown, a vehicle height sensor 31 is also provided in each suspension mechanism of the front, rear, left and right vehicle frames. Each oil amount control valve 16 performs a feedback control of the oil amount of each hydraulic actuator 19 in accordance with a control voltage from an electronic control unit comprising a micro computer. When the front, rear, left and right hydraulic actuators 19 are specified, subscripts of FL, FR, RL, and RR are added. Assuming that the relative vehicle height of the vehicle frame 25 with respect to each axle or wheel 20 is hFL-hRR, and the relative vehicle height of each of the front, rear, left and right portions of the cab 3 with respect to the vehicle frame 25 is hcFL-hcRR, the vehicle height change amount of the vehicle frame 25 xFL to xRR and the vehicle height change amounts xcFL to xcRR of the cab 3 are expressed by the following equations. XFL = hFL-hFL0, xFR = hFR-hFR0 xRL = hRL-hRL0, xRR = hRR-hRR0 xcFL = hcFL-hcFL0, xcFR = hcFR-hcFR0 xcRL = hcRL-hcRL0, xcRR = hcRR 1) However, hFL0 to hRR0: standard vehicle height of each wheel supporting portion of the vehicle frame hcFL0 to hcRR0: relative displacement amounts Δφ, Δ of the respective modes with respect to the road surface of the standard vehicle height vehicle frame 25 at the front, rear, left and right portions of the cab.
θ, Δx, and the relative displacement amounts Δφc, Δθc, Δxc of each mode with respect to the vehicle frame 25 of the cab 3 are represented by the following equations, respectively. Δφ = kφ1 (xFL−xFR) + kφ2 (xRL−xRR) Δθ = kθ1 (xFL + xFR) −kθ2 (xRL + xRR) Δx = kx1 (xFL + xFR) + kx2 (xRL + xRR) Δφc = kc φ1 (xcFL−xcFR) + kφ xcRL-xcRR) [Delta] [theta] c = kc [theta] 1 (xcFL + xcFR) -kc [theta] 2 (xcRL + xcRR) [Delta] xc = kcx1 (xcFL + xcFR) + kcx2 (xcRL + xcRR) ... [1], k1; Determined constants kφ2, kθ2, kx2: Constants determined by vehicle specifications kc φ1, kc θ1, kc x1: Constants determined by vehicle specifications kc φ2, kc θ2, kc x2: Constants determined by vehicle specifications For each axle or wheel 20 Assuming that the displacement of each mode of the road surface input that acts is φ, θ, x, the relative displacement φ2, θ2, x2 of each mode of the cab 3 can be expressed by the following equation. Φ2 = φ + Δφ + Δφc θ2 = θ + Δθ + Δθcx2 = x + Δx + Δxc (3) Therefore, in order to keep the cab 3 flat (parallel to the road surface), the control amount (force) of each mode to be added to the cab 3 by each hydraulic actuator 19 ) -F12, -F22 and -F32 can be represented by the following equations. −F12 = −k1 [φ] −k2d [φ] dt−k7Σ [φ] dt−F22 = −k3 [θ] −k4d [θ] dt−k88 [θ] dt−F32 = −k5 [x] −k6 d [x] dt−k9 Σ [x] dt (4) where [φ] is the roll displacement of the cab relative to the road surface (Δφ + Δφc) [θ] is the pitch displacement of the cab relative to the road surface (Δθ + Δ
θc) [x]: The amount of bounce displacement of the cab relative to the road surface (Δx +
Δxc) k1 to k9: control parameter Σ: represents an integral symbol (◆) for convenience. In the present invention, the control parameters k1 to k9 of the above equation (4) can be changed so that a comfortable ride can be obtained on any road surface conditions. The transfer function from the roll displacement φ of the road input to the roll displacement [φ] of the cab with respect to the road is Hφ, and the pitch displacement of the cab with respect to the road [θ] from the pitch displacement θ of the road input.
If the transfer function from the bounce displacement x of the road surface input to the bounce displacement [x] of the cab relative to the road surface is Hx, the transfer function up to H.theta.
The transfer functions Hφ, Hθ, and Hx of each bounce mode are expressed by the following equations. [0021] ^{Hφ = - (IX s 3 -Mc} ghr s) / (IX s 3 + k2 s 2 + k1 s-Mc ghr s + k7) = (Δφ + Δφc) / φ Hθ = - (IY s 3 -Mc ghp s) / ( ^{IY s 3 + k4 s 2 +} k3 s-Mc ghp s + k8) = where (Δθ + Δθc) / θ Hx = -Mc s 3 / (Mc s 3 + k6 s 2 + k5 s + k9) = (Δx + Δxc) / x ...... (5), IX : Cabinet roll inertia moment IY: Cabinet pitch inertia moment Mc: Cabinet mass g: Acceleration of gravity hr: Height difference between the center of gravity of the cap and the roll center hp: Height difference between the center of gravity of the cab and the center of pitch s: Operator and And the power spectral densities of the displacement amounts φ, θ, x of the roll, pitch, and bounce modes of the road surface input are Sφ, S
Assuming that the power spectral densities of the relative displacement amounts of each mode of the roll, pitch and bounce of the cab with respect to the road surface are SΔφ, SΔθ, and SΔx, the following relationship is obtained between the power spectral densities of the two for each frequency. is there. Sφ = SΔφ / [Hφ] ² Sθ = SΔθ / [Hθ] ² Sx = SΔx / [Hx] ² (6) Now, the transfer functions Hφ, Hθ, Hx can be calculated for each frequency,
The relative displacement [φ] of each mode of the cab to the road surface,
Since [θ] and [x] are always detected, the power spectral densities SΔφ, SΔθ, and SΔx of the relative displacement of each mode of the cab with respect to the road surface are also obtained. Therefore, the power spectrum densities Sφ, Sθ, and Sx of the displacement amount of each mode of the road surface input, that is, the road surface condition can be known from the above equation (6). Next, the obtained power spectrum densities Sφ, Sθ, and Sx of the displacement amounts of the respective modes of the road surface input are determined in advance by a frequency characteristic diagram shown in FIG. 3 (representing only the power spectrum density Sφ). The set frequency fi (i = 1 to
n), and the respective frequency regions 0 to f1, f1 to f2,.
The area Aφ1, of the area Aφi, Aθi, Axi of fn-1 to fn
The area ratios γφi, γθi, γxi to Aθ1, Ax1 are determined. Aφ1, Aφ2,... Aφn, area ratio γφi = Aφi / Aφ1 Sφ surrounds Aθ1, Aθ2,... Aθn, area ratio γθi =
Aθi / Aθ1 Areas Ax1, Ax2,... Axn surrounded by Sx, area ratio γxi =
Axi / Ax1 From the area ratio γφi, γθi, γxi of each frequency domain,
Control parameters k1 to k for each mode of pitch and bounce
Determine 9 Specifically, the control parameters k1 to k9 suitable for many road surface conditions are determined by changing the area ratios γφi, γθi, γxi
Is determined experimentally in advance as a function of, and is set in a ROM of a microcomputer as an electronic control device as a control map, and is automatically selected. The control parameters k1 to k9 can be calculated more finely by narrowing the division of the displacement amount of each mode of the road surface input by the frequency of the power spectral densities Sφ, Sθ, and Sx. Note that the area ratios γφi, γθi, γxi are obtained by dividing each frequency region fi−1 with respect to the area of all frequency regions f1 to fn.
To fi. K1 = k1 (γφ2, γφ3, ... γφn) k2 = k2 (γφ2, γφ3, ... γφn) k3 = k3 (γθ2, γθ3, ... γθn) k4 = k4 (γθ2, γθ3, ... γθn) k5 = k5 (Γx2, γx3, ... γxn) k6 = k6 (γx2, γx3, ... γxn) k7 = k7 (γφ2, γφ3, ... γφn) k8 = k8 (γθ2, γθ3, ... γθn) k9 = k9 (γx2, γx3, ... γxn) (7) As shown in FIG. 4, for example, a frequency characteristic diagram representing the power spectral density Sφ of the roll displacement amount of the road surface input is represented by 1
When divided by two frequencies, the control parameter k1 obtained from the area ratio γφ2 of the two frequency regions is preferably set in advance so as to change more gradually than the step-like shape in accordance with the area ratio γφ2. From the control amounts F12, F22, and F32 of each mode of the cab using the above-mentioned control parameters k1 to k9, the control voltages VcFL to VcR of the respective oil amount control valves 16 represented by the following equations are obtained.
Find R. VcFL = -KV1 F12-KV2 F22 + KV5 F32 VcFR = + KV1 F12-KV2 F22 + KV5 F32 VcRL = -KV3 F12 + KV4 F22 + KV6 F32 VcRR = + KV3F12 + KV6 F32 VcV = + KV3F12 + KV3F12 + KV3V12 + KV3F12 + KV3V12 + KV3V12 + KV3F12 + KV3F12 + KV3F32 + 8 By driving each oil amount control valve 16 and controlling the hydraulic actuator 19 by using the feedback feedback voltages VsFL to VsRR from the hydraulic pressure sensor 17, the attitude of the cab 3 can be maintained substantially flat (parallel to the road surface). As shown in FIG. 2, according to the present invention, the vehicle height sensor 31 detects the vehicle heights hFL to hRR of the vehicle frame 25 based on the above-described principle.
From the vehicle height sensor 28, the vehicle height hcFL to hcR of the cab 3.
R, respectively, and the relative displacement calculating means 35 calculates the vehicle heights hFL to hRR of the vehicle frame 25 and the vehicle heights hcFL to hcR of the cab 3.
From R, the vehicle height change amounts xFL to xRR of the vehicle frame 25 and the vehicle height change amounts xcFL to xcRR of the cap 3 are obtained, and the relative displacement amounts Δφ, Δθ, Δx of each mode of the vehicle frame 25 with respect to the road surface are obtained.
And the relative displacement amounts Δφc, Δθc, Δxc of each mode of the cab 3 with respect to the vehicle frame 25 are obtained. When a change command is issued from the control parameter change command means 33, the control parameter nki is changed as follows.
Is newly calculated. From the power spectrum densities SΔφ, SΔθ, SΔx of the relative displacement of each mode of the cab with respect to the road surface, the control parameter calculating means 34 calculates the power spectrum densities Sφ, S of the displacement of each mode of the road input.
θ and Sx are obtained, and the frequency characteristic diagram thereof is converted to a predetermined frequency f
i (i = 1 to n), and each frequency domain 0 to f1, f1
F2,... Fn-1 to fn, the area ratios .gamma..phi.i, .gamma..theta.i, .gamma.xi of the areas A.phi.i, A.theta.i, Axi and the areas A.phi.1, A.theta.1, Ax1 are obtained. Is determined. The difference between each control parameter nki newly obtained by the control parameter gradual change means 36 and each control parameter ki thus far, that is, the amount of change is gradually changed by a constant value in a plurality of control cycles. Next, the relative displacement amounts Δφ, Δθ, Δx of the respective modes of the vehicle frame 25 with respect to the road surface are calculated by the control amount calculating means 37.
From the relative displacement amounts Δφc, Δθc, Δxc of the mode of the cab 3 with respect to the vehicle frame 25 and the control parameters that gradually change, the control amounts F12, F22, F32 of the modes of the cab 3 are obtained.
Ask for. Finally, the control amount F1 of each mode of the cab 3
From 2, F22, F32, the control voltage VcFL of each oil amount control valve 16
ＶVcRR, each of the oil quantity control valves 16 is driven by the control voltages VcFL VcRR and the feedback voltage FsFL〜FsRR from the hydraulic pressure sensor 17, and each hydraulic actuator 19
To adjust the amount of oil. FIGS. 5 to 10 are flow charts of a control program for performing the above-described control by the electronic control unit composed of a microcomputer. This control program is repeatedly executed at predetermined time intervals. p11-p77, p81-p86, p91-p
96, p101 to p107 represent each step of the control program. The control program is started at p11 in FIGS. 5 to 7, initialization is performed at p12, and the hydraulic pressure holding routine shown in FIG.
The hydraulic control valve 12 is driven to maintain the output hydraulic pressure pm at a predetermined value pc. At p14, the vehicle height hFL-hRR of the vehicle frame 25 is obtained from the vehicle height sensor 31 and the vehicle height hcF of the cab 3 is obtained from the vehicle height sensor 28.
Read L to hcRR respectively. At p15, the vehicle height change amounts xFL-xRR of the vehicle frame 25 are obtained from the vehicle heights hFL-hRR of the vehicle frame 25, and the vehicle height change amounts xcFL-xcRR of the cab 3 are obtained from the vehicle heights hcFL-hcRR of the cab 3, respectively. At p16, the relative displacement amounts .DELTA..phi., .DELTA..theta.
And the relative displacement amounts Δφc, Δθc, Δxc of each mode of the cab 3 from the vehicle height change amounts xcFL to xcRR of the cab 3.
Ask for. At p17, the relative displacement [φ], [θ], [x] of each mode of the cab 3 with respect to the road surface are sequentially stored in the RAM. At p18, it is determined whether or not a control parameter change command has been received from the control parameter change command means 33. If there is no control parameter change command, the process proceeds to p20. If there is a control parameter change command, the process proceeds to the control parameter calculation routine shown in FIG. 9 at p19, where a new control parameter nki is obtained. At p20, according to the sign of the difference between each new control parameter nk1 and the previous control parameter k1, p
At 23 and p21, the change amount dk1 per control cycle is adjusted, and at p24 and p22, it is determined whether or not the difference between each new control parameter nk1 and the previous control parameter k1 has been reversed. If the difference between each new control parameter nk1 and the previous control parameter k1 is not reversed, p25
Is changed to a value obtained by adding or subtracting the control parameter, and when the difference between each new control parameter nk1 and each control parameter k1 up to now is reversed, the control parameter change is stopped. Similarly, in p26 to p73, each control parameter ki is incremented or decremented by a fixed value dki every control cycle.
Proceed to p74. Thus, in each of a plurality of control cycles, each control parameter ki thus far is replaced with a new control parameter nki
To be changed. At p74, the control amounts F12, F22 and F32 of the respective modes of the cab 3 are obtained from the relative displacement amounts [φ], [θ] and [x] of the respective modes of the cab 3 with respect to the road surface. At p75, control voltages VcFL to VcRR of the oil amount control valve 16 corresponding to the control amounts F12, F22, and F32 of each mode of the cab 3 are obtained. p76
Then, in the hydraulic actuator driving routine shown in FIG. 10, the oil amount of each hydraulic actuator 19 is adjusted by each oil amount control valve 16, and the process ends at p77. As shown in FIG. 8, the hydraulic pressure holding routine is p
Starting at 81, the output oil pressure pm of the hydraulic pump 4 is read by the oil pressure sensor 9 at p82, and it is determined at p83 whether or not the output oil pressure pm is larger than the predetermined value pc, and when the output oil pressure pm is smaller than the predetermined value pc. Closes the hydraulic control valve 12 at p84 and proceeds to p86. If the output hydraulic pressure pm is greater than the predetermined value pc, the hydraulic control valve 12 is opened at p85 to lower the output hydraulic pressure pm, and the output hydraulic pressure pm is maintained at the predetermined value pc. To return to this program. As shown in FIG. 9, the control parameter calculation routine is started at p91, and at p92, the relative displacement [φ], [θ], [x] of each mode of the cab 3 with respect to the road surface is calculated from the cab 3 with respect to the road surface. The power spectrum densities SΔφ, SΔθ, SΔx of the relative displacement amounts of the respective modes are obtained. At p93, from the power spectrum densities SΔφ, SΔθ, SΔx of the relative displacement amounts of each mode of the cab 3 with respect to the road surface, the power spectrum densities Sφ, S of the displacement amounts of each mode of the road surface input are obtained.
Find θ and Sx. Each of the frequency ranges 0 to f1, f1 to f2,.
The area Aφi, Aθi, Axi and the area Aφ1,
The area ratios γφi, γθi, γxi with Aθ1, Ax1 are obtained, and p
At 95, a new control parameter nki is obtained from the area ratios γφi, γθi, γxi, and the program returns to p96 at p96. As shown in FIG. 10, the hydraulic actuator driving routine starts at p101, the hydraulic pressures pFL to pRR of the hydraulic actuators 19 are read from the hydraulic pressure sensors 17 at p102, and the hydraulic pressures pFL to pRR are converted to the voltages VsFL to VsR at p103.
Convert to R At p104, the control voltages VcFL to VcRR
The excitation voltages VeFL-VeRR of each oil amount control valve 16 are obtained from the voltages VsFL-VsRR. At p105, each oil amount control valve 16 is excited, and the amount of oil QFL-QRR to be supplied to or discharged from each hydraulic actuator 19 is adjusted. Each hydraulic actuator 19 is driven at p106, and the program returns to p107. As shown in FIG. 11, the amount of oil QFL to QRR to each hydraulic actuator 19 is adjusted by the excitation voltage VeFL to VeRR of each oil amount control valve 16. As described above, the present invention provides a hydraulic actuator for supporting four points on the vehicle frame at the left, right, front and rear sides of the car, and a vehicle disposed on the wheel support of the vehicle frame and the cabinet support of the vehicle frame, respectively. From the height sensor and the amount of change in the vehicle height relative to the road surface detected by the vehicle height sensor,
From the relative displacement amount calculating means for calculating the relative displacement amount of each mode of the pitch and bounce, and the power spectrum density of the relative displacement amount of each mode of the cab, the power spectrum density of the displacement amount of each mode of the road surface input is obtained. A control parameter calculating means for obtaining a control parameter from an area ratio of each frequency domain obtained by dividing the characteristic diagram at a predetermined frequency; a control parameter change amount per control cycle being set to a constant value; Control parameter gradual change means for gradually changing the control parameter, cab control amount calculating means for obtaining a control force for suppressing the displacement of each mode of the cab from the control parameter gradual change means, and control force for suppressing the displacement of each mode of the cab. And the electromagnetic oil amount control valve that generates the hydraulic actuators, the current control parameters and Even if Do control parameter difference is significantly large, it is possible to prevent behavior changes abruptly cab when changing the control parameters, the but connexion, can be further improved ride and comfort.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a hydraulic circuit diagram of a cabinet attitude control device according to the present invention. FIG. 2 is a block diagram of the attitude control device. FIG. 3 is an explanatory diagram of control parameter calculation means in the attitude control device. FIG. 4 is an explanatory diagram of control parameter calculation means in the attitude control device. FIG. 5 is a flowchart of a control program of the attitude control device. FIG. 6 is a flowchart of a control program of the attitude control device. FIG. 7 is a flowchart of a control program of the attitude control device. FIG. 8 is a flowchart of a control program of the attitude control device. FIG. 9 is a flowchart of a control program of the attitude control device. FIG. 10 is a flowchart of a control program of the attitude control device. FIG. 11 is a diagram illustrating a relationship between an excitation voltage of an oil amount control valve and an oil amount. [Description of Signs] 3: Cab 16: Oil amount control valve 17: Oil pressure sensor 1
9: Hydraulic actuator 20: Wheel 25: Vehicle frame 28, 31: Vehicle height sensor 3
3: control parameter change instructing means 34: control parameter calculating means 35: relative displacement amount calculating means 36: control parameter gradual changing means 37: control amount calculating means

Claims (1)

(57) [Claims 1] A hydraulic actuator for supporting four points on the vehicle frame, that is, left, right, front and rear, respectively, and a vehicle height sensor disposed on each of the wheel support portion of the vehicle frame and the cabinet support portion of the vehicle frame. A relative displacement calculating means for calculating the relative displacement of each mode of the roll, pitch, and bounce from the change in the vehicle height with respect to the road surface detected by the vehicle height sensor, and the relative displacement of each mode of the cab. From the power spectral density,
Control parameter calculating means for obtaining a power spectrum density of a displacement amount of each mode of a road surface input, and obtaining a control parameter from an area ratio of each frequency region obtained by dividing a frequency characteristic diagram thereof by a predetermined frequency; and a control per control cycle. Control parameter gradual change means for setting the parameter change amount to a constant value and gradually changing to a new control parameter in a plurality of control cycles, and a cab for obtaining a control force for suppressing the displacement of each mode of the cab from the control parameter gradual change means. An attitude control device for a cab, comprising: a control amount calculating means; and an electromagnetic oil amount control valve for causing each of said hydraulic actuators to generate a control force for suppressing a displacement amount of each mode of said cab.