JP7459710B2 - Lift/tilt control device for automated guided vehicles - Google Patents

Description

The present invention relates to lifting and transporting luggage using an automated guided vehicle (AGV), and particularly relates to technology for controlling the elevation and inclination of luggage.

Automatic guided vehicles such as those disclosed in Patent Document 1 are equipped with a motor for lifting and lowering cargo in addition to a driving motor. In the platform stabilizing device disclosed in Patent Document 2, the inclination (lateral direction and traveling direction) of the top plate (base) is controlled by two elevating shafts using servo motors.

Patent document 3 deals with a method for correcting the thrust constant using a table when controlling a stage using a multi-axis linear actuator.

In addition, as a study related to the control of the present invention, Non-Patent Document 1 describes control based on mode space.

JP 2019-204538 A JP2019-093981A Japanese Patent Application Publication No. 2005-150615

Shunsuke Yajima, Seiichiro Katsura, "Non-interfering bilateral control based on mode space observer in a different mass master-slave system", Electrical Engineering Theory D, vol. 133-2, pp. 172-180, 2013

As described in Non-Patent Document 1, research into control based on mode space has been conducted in the study of remotely operated devices, but as far as we have investigated, there have been no confirmed examples of its application to AGVs (especially their lifting and tilting devices).

Furthermore, it is difficult to design a control system using actuators to control the elevation, lateral inclination, and forward direction inclination of an AGV's luggage lifting cart, etc.

The present invention aims to solve the above problems, and its purpose is to provide a lifting/tilting control device for an automated guided vehicle that reduces the impact when the actuator output shaft comes into contact with a controlled object such as a cart or tabletop on which cargo is loaded, and can smoothly control the lifting/tilting while controlling the tilt of the controlled object.

In order to solve the above problem, the lifting/tilting control device for an automated guided vehicle according to claim 1 comprises:
A base mounted on a movable traveling body;
First to fourth actuators are respectively installed at the four corners of the base, and the output shafts of the actuators are configured to be movable in a direction perpendicular to a surface on which the actuators are installed on the base ;
a controlled body disposed opposite to a tip end of each of the output shafts of the first to fourth actuators;
a position control unit that extends the first to fourth actuators by a force that is sufficiently smaller than the load of the controlled body, and controls the position of each of the output shafts of the first to fourth actuators while controlling the inclination of the controlled body after the tip of the output shaft of each actuator comes into contact with the controlled body and stops;
Equipped with

The position control unit is
a command value generating unit that converts the center height command of the controlled object and the tilt command of the controlled object into a mode position command using the following equations (1), (2), and (3);

(However, x ₁ to x ₄ are the positions of the tips of the output shafts of the first to fourth actuators in the controlled object, X ₁ is the mode variable corresponding to the elevation of the controlled object, and X ₁ = (x _{1 +} x _{2 + x 3 +} x ₂ + x ₃ - x ₄ )/4, and the proportional relationship with the lateral slope S _x is X ₂ = (d ₁₂ / ₂ ) _S 2; the distance between the tips of the output shafts of the actuators; _X3 is the mode variable corresponding to the inclination of the controlled object in the direction of movement (direction of rotation with the y-axis as the rotation axis). _{It is defined as ​ ​ ​ ​ ​ ​} The distance between the tip of the output shaft and the tip of the output _shaft of the ^third actuator; S _x ^cmd is the tilt command in the lateral direction (with respect to the x-axis) of the controlled object, S _y ^cmd is the tilt command in the traveling direction (with respect to the y-axis) of the controlled object, X ₁ ^cmd to X ₄ ^cmd is the mode position command value),
The position command of the mode converted by the command value generation unit and the response value of the mode obtained by converting the position response value of the output shaft of each actuator into a variable by performing position control on the first to fourth actuators. a position controller that calculates a mode force reference value based on equation (4);

(However, C _PM1 to C _PM4 are the characteristics of the position controller, X ₁ ^cmd to X ₄ ^cmd are the mode position command values, X ₁ ^res to X ₄ ^res are the mode response values, and F ₁ ^ref to F ₄ ^ref are the mode variable force reference value),
a variable conversion unit that converts the mode force reference value determined by the position controller into the force reference value of the output shaft of the first to fourth actuators using equation (5);

(where T ^-1 is the inverse matrix of the transformation matrix)
The present invention is characterized by comprising:

The lifting/tilting control device for an automatic guided vehicle according to claim 2 is the device according to claim 1,
The position control unit is
When there is no load on the controlled object, equal forces are applied to the first to fourth actuators to extend each output shaft, and when the tip of the output shaft of each actuator comes into contact with the controlled object and stops, the deviation of the actuator output shaft length from the average is stored, and when the load is transported, the deviation is added to the position response value of the output shaft of each actuator.

The lifting/tilting control device for an automatic guided vehicle according to claim 3 is the device according to claim 1 or 2 ,
The position control unit is
Calculating the position L of the output shaft of the first to fourth actuators when the tip ends of the output shafts of the actuators come into contact with the controlled object using equation (6);

(However, f ₀ ^ref is the output shaft force reference value when no force is applied to each actuator, k is the elastic coefficient of the actuator, and L ₀ is the natural length when no force is applied to each actuator.)
It is characterized in that the calculated position L is applied to x ₁ to x ₄ in equation (1).

The elevation/inclination control device for an automatic guided vehicle according to claim 4 is any one of claims 1 to 3 , comprising:
comprising a tilt sensor installed on the base;
The position control unit includes a coordinate conversion unit that calculates a tilt command in the base coordinate system by calculating the following equation (7), and converts the determined tilt command in the base coordinate system into the command value. It is characterized in that it is a tilt command for the controlled object in the generation section.

(However, S _Bx ^cmd is a horizontal tilt command of the controlled object in the base coordinate system, S _By ^cmd is a tilt command in the advancing direction of the controlled object in the base coordinate system, and S _Wx ^cmd is the world coordinate system. S W x ^B is the horizontal tilt command of the controlled object in the world coordinate system, S _Wx B is the tilt command in the direction of movement of the controlled object in the world coordinate system, and S _Wx ^B is the command for the controlled object in the world coordinate system detected by the tilt sensor. (S _Wy ^B is the inclination in the direction of movement of the controlled object in the world coordinate system detected by the inclination sensor)

(1) According to the invention described in claims 1 to 4 , the impact when the first to fourth actuators come into contact with the controlled object (cart, tabletop, etc.) is small, and the controlled object can be lifted smoothly while controlling the inclination of the controlled object. In addition, it is possible to independently design the control parameters for the center height, lateral inclination, forward inclination, and distortion of the controlled object, making it easy to adjust the control gain. In addition, because distortion is used as a control parameter, it is possible to absorb errors from the contact surface between the output shaft of each actuator and the controlled object.
(2) According to the invention described in claim 2 , the inclination of the controlled object can be calculated with high accuracy.
(3) According to the invention described in claim 3 , the position of the output shaft of each actuator can be calculated correctly regardless of the state of the force applied to each actuator, thereby improving control accuracy.
(4) According to the invention described in claim 4 , even if the base mounted on the traveling body is tilted, the tilt of the controlled body can be controlled. For example, even if the base is tilted due to traveling on a slope, the tilt of the controlled body can be kept horizontal.

FIG. 1 is a schematic diagram of a lifting/tilting device according to an embodiment of the present invention. FIG. 1 is a diagram showing the overall configuration of a system according to a first embodiment of the present invention. 1 is a configuration diagram of a controller according to a first embodiment of the present invention. 1 is a block diagram of a control system according to a first embodiment of the present invention. FIG. FIG. 2 is an explanatory diagram showing the correspondence between numbers of automatic guided vehicles (AGV) and actuators in Embodiment 1 of the present invention. FIG. 11 is a diagram showing the overall configuration of a system according to a second embodiment of the present invention. FIG. 11 is a configuration diagram of a controller according to a second embodiment of the present invention. FIG. 11 is an explanatory diagram showing the results of an experiment on the control performance of the second embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings, but the present invention is not limited to the following embodiment.

Figure 1 shows an overview of the lifting/tilting device according to the first embodiment. In Figure 1, a base 20 is mounted and fixed to an automated guided vehicle (mobile running body) 10, and the stators of the first to fourth actuators 31 to 34 are fixed to the four corners of the base 20.

Each output shaft of the first to fourth actuators 31 to 34 has a degree of freedom of movement in the vertical direction, and a controlled object 40 such as a cargo cart, a top plate, or a cage cart is disposed opposite the tip of each output shaft.

At the location where the tip of each output shaft of the actuators 31 to 34 comes into contact with the controlled object 40 due to the extension of the output shaft, a connection mechanism (not shown) is provided that movably supports the controlled object 40 via the tip of each output shaft.

This connection mechanism allows the output shaft of the actuator to come into contact with the controlled object 40 even when the controlled object 40 is tilted, and is configured to allow the controlled object 40 to tilt.

The automated guided vehicle 10 is equipped with a motor for driving the vehicle, a motor for raising and lowering and tilting the controlled object (motors for driving the actuators 31 to 34), etc., but these are not shown in the figure. In addition, the actuators 31 to 34 in this embodiment are, for example, ball screw mechanisms.

Next, the overall system configuration of the lifting/tilting device, including the position control unit of the present invention, is shown in Figure 2. The thick lines in Figure 2 indicate mechanical connections. In Figure 2, 61 is a controller equipped with the function of a position control unit. Controller 61 applies thrust to actuators 31 to 34, and the thrust value is determined by feeding back information on the actuator length.

The configuration of the controller 61 is shown in Fig. 3. In Fig. 3, reference numeral 62 denotes a command value generating unit, which converts the command values of the center height and inclination of the controlled body 40 into variables based on geometric relationships, and calculates a position command value X ^cmd of the mode (modal space).

The position response value ^xres of the actuator output shaft (response value of the actuator extension length) is measured directly by a position sensor in the case of a direct drive linear motor. When using a transmission mechanism such as a ball screw instead of a direct drive, the actuator length is calculated using a constant such as lead.

Reference numeral 63 denotes a variable conversion unit that converts variables of the position response value ^xres of the output shaft of the actuator based on the definition of the modal space (Equation (3) described later) to calculate a modal response value ^Xres .

A position control system is constructed by a position controller 64 based on the position command value X ^cmd of the mode and the response value X ^res of the mode, and the force reference value F ^ref of the mode is output from the position controller 64 .

Reference numeral 65 denotes a variable conversion unit that converts the force reference value F ^ref of the mode into a force reference value f ^ref of the output shaft of the actuator using equation (5) described later. This output shaft force reference value f ^ref becomes the final control input to the first to fourth actuators 31 to 34.

A block diagram of the control system of the first embodiment is shown in FIG. In FIG. 4, the same parts as those in FIG. 3 are designated by the same reference numerals. 64a in the controller 61 is a subtracter that takes the deviation between the mode position command value X ^cmd and the mode response value X ^res , and C _p (s) is the position control gain of the mode position controller 64.

70 is a motor driver for each actuator, and f _a ^ref represents the thrust of the output shaft of the actuator. A subtracter 71 calculates the deviation between the thrust force f _a ^ref and the disturbance f ^ext of the plant (controlled objects 40 such as trolleys and top plates, loads on controlled objects, etc.), and a coefficient assigning section is applied to the deviation. By applying the force-position conversion coefficient 1/Ms ² of 72, the position response value x ^res of the output shaft is output.

Figure 5 shows the positional relationship of each actuator in the controlled object 40, with Actuators 1 to 4 in the figure indicating the positions of the first to fourth actuators 31 to 34.

Next, the operation of the controller 61 in Figures 3 and 4 will be specifically described. The equations for converting the position and inclination of the actuator can be expressed as equations ₍₁ ) and (2) using the mode variable X = [ _X1 , _X2 , _X3 , _X4 ] of each function and the actuator position vector x = [ _x1 , _x2 , x3, _x4 ].

Here, the mode variable _X1 corresponds to elevation, _X2 corresponds to inclination in the lateral direction (rotation direction about the x-axis), _X3 corresponds to inclination in the advancement direction (rotation direction about the y-axis), and _X4 corresponds to distortion.

Furthermore, the variable conversion from the center height/tilt command [H ^cmd , S _x ^cmd , _Sy ^cmd ] to the mode command X ^cmd = [X ₁ ^cmd , X ₂ ^cmd , X ₃ ^cmd , X ₄ ^cmd ] performed by the command value generation unit 62 in Figures 3 and 4 can be expressed as equation (3).

where _x1 to _x4 are the positions of the tips of the output shafts of the first to fourth actuators in the controlled body, and _X1 is a mode variable corresponding to the elevation of the controlled body and is defined as _X1 = ( _x1 + _x2 + _x3 + _x4 )/4.

X ₂ is a mode variable corresponding to the inclination of the controlled object in the lateral direction (rotation direction with the x-axis as the rotation axis), and is defined as X ₂ = (x ₁ - _{x 2} + x ₃ - _{x 4} )/4, The horizontal inclination S _x and the proportional relationship X ₂ = (d ₁₂ /2) S _x (d ₁₂ is the distance between the tip of the output shaft of the first actuator and the tip of the output shaft of the second actuator; (actuator left and right spacing).

_X3 is a mode variable corresponding to the inclination of the controlled object's direction of travel (rotation direction about the y-axis as the rotation axis) and is defined as _X3 = ( _x1 + _x2 - _x3 - _x4 )/4, and is proportional to the inclination S _y in the direction of travel, _X3 = ( _d13 /2) S _y ( _d13 is the distance between the tip of the output shaft of the first actuator and the tip of the output shaft of the third actuator; actuator front-to-rear spacing).

_X4 is a mode variable corresponding to the distortion of the controlled body, H ^cmd is a center height command of the controlled body, S _x ^cmd is a lateral tilt command (relative to the x-axis) of the controlled body, S _y ^cmd is a tilt command (relative to the y-axis) of the controlled body in the traveling direction, and _X1 ^cmd to _X4 ^cmd are position command values of the mode.

The position controller 64 determines the force reference value F ^ref of the mode using equation (4) based on the deviation between the mode position command value X ^cmd input from the subtractor 64 a and the mode response value X ^res .

where C _PM1 to C _PM4 are the characteristics of the controller (such as PID), X ₁ ^cmd to X ₄ ^cmd are the position command values of the modes, X ₁ ^res to X ₄ ^res are the response values of the modes, and F ₁ ^ref to F ₄ ^ref are the force reference values of the mode variables.

In this embodiment, the controller for the mode variables of each function is directly incorporated into the position controller 64, as shown in equation (4), so the control performance of each function can be directly designed.

In other words, while conventional methods make it possible to change the control gain for each axis of the actuator, it is difficult to adjust the weighting of the control gain for each function, such as tilt control and height control.

On the other hand, in the present invention, since a control system is constructed for the mode variables of each function, control gains regarding each function can be directly designed.

To convert the force reference value F ^ref of the mode variable to the force reference value f ^ref of the actuator output shaft, the variable converter 65 multiplies F ^ref by the inverse matrix T ⁻¹ of the conversion matrix as shown in equation (5). It can be realized with.

Next, correction values for contact and geometric errors on the controlled object 40 will be explained.

When the controlled object 40 is pushed up by the actuators 31 to 34, the distance between the AGV 10 and the controlled object 40 at the point of contact between the controlled object and the actuators 31 to 34 is not necessarily equal due to structural and manufacturing errors. Therefore, when the inclination of the controlled body 40 is calculated from the extension length of the actuators 31 to 34, an error occurs in calculating the inclination of the load.

Therefore, an equal force (sufficiently smaller than the weight of the controlled object 40) is applied to each actuator in an unloaded state to extend the actuator, and the actuator is stopped when the output shaft of the actuator contacts the bottom of the controlled object 40. The difference in length from the average is stored as a correction value.

Then, when a load is being transported, the stored correction value is added to the actuator detection length to calculate the position and inclination of the controlled object 40.

Furthermore, when starting the elevation/tilting control, if the actuators 31 to 34 start the control from a state where they are not in contact with the controlled object 40, the load will be lower than when the actuators are in contact with the controlled object 40 and the actuators are lifting the controlled object 40. is extremely light, and a controller that is adjusted to be stable while being lifted tends to become unstable.

For this purpose, an equal (small) force is first applied to each of the actuators 31 to 34, and the actuators are extended until they stop and come into contact with the controlled object 40. The reason why the forces are equal is to detect the longest distance between the AGV 10 and the controlled object 40, and the height command of the controlled object 40 is set to be equal to or greater than the sum of this value and the actuator mounting height. Further, the reason why a small force is applied is to reduce the impact upon contact.

Next, we will explain how to correct the length when the actuator is elastic.

When the actuator has elasticity, the relationship between the displacement on the input side and the position of the output shaft varies depending on the force. Therefore, the actuator position is calculated based on Hooke's law. In other words, the position L of the actuator output shaft when it contacts the controlled body 40 is calculated using equation (6) from Hooke's law.

where f ₀ ^ref is the force reference value of the output shaft when no force is applied to each actuator, k is the elastic coefficient of the actuator, and L ₀ is the natural length when no force is applied to each actuator.

Then, by applying the position L calculated by the above equation (6) to x ₁ to x ₄ of the above equation (1), the length can be corrected when the actuator has elasticity.

As described above, according to the first embodiment, when the output shafts of the first to fourth actuators 31 to 34 come into contact with the controlled object (such as a truck or a top plate) 40, the impact is small and the controlled object 40 is It can be lifted smoothly while controlling the tilt.

In addition, the configurations shown in Figures 3 and 4 make it possible to independently design control parameters related to center height, lateral tilt, travel direction tilt, and distortion, making it easy to adjust the control gain.

Further, calculation of constraint conditions is not required, which simplifies the calculation. Furthermore, the influence of distortion on the contact surface of the controlled body 40 can be reduced. The actuator has four axes, and we want to control three variables (height position, tilt [vertical, horizontal]). Therefore, it is conceivable to calculate the command values of the actuators by adding a constraint condition that the tip positions of the output shafts of the actuators 31 to 34 are on the same plane. However, the position where the actuator contacts the controlled object 40 is not necessarily on a perfect plane, and the actuator does not always contact the controlled object 40 at the same position. Therefore, by detecting errors from the same plane as distortion and using this as a control target, the errors from the same plane are absorbed. The control system for distortion should be flexible enough to tolerate errors.

In addition, the actuators 31 to 34 are elastic bodies whose length changes depending on the force applied to them, so if the position and inclination of the controlled body 40 are calculated based on the length when no force is applied, an error will occur. For this reason, accurate height and inclination control can be achieved by correcting the actuator position based on the force using equation (6).

In the second embodiment, a function is added to control the tilt even when the AGV 10 is tilted, such as keeping the controlled object 40 horizontal even when the AGV 10 is tilted. In the second embodiment, in addition to the system of the first embodiment, a tilt sensor 90 is installed on the base 20 as shown in FIG. 6, and the measured value of the tilt is fed back to the controller 61.

Two tilt sensors 90 are installed so that they can detect the inclination of the AGV 10 in the longitudinal direction and in the direction of travel. The AGV 10 tilts due to the influence of road surface conditions (inclination, unevenness), mechanical errors, wheel distortion (due to an imbalance in forces applied due to the center of gravity of the controlled object 40 and the cargo), etc. For this reason, even if the inclination of the controlled object 40 relative to the AGV 10 is controlled to a command value, the inclination of the controlled object 40 will not be as commanded.

The configuration of the controller 61 in the second embodiment is shown in FIG. 7. In FIG. 7, the same parts as in FIG. 3 are denoted by the same reference numerals. In FIG. 7, the world coordinate system is an orthogonal coordinate system on the horizontal ground, and the base coordinate system is an orthogonal coordinate system (the origin is the center of the actuator mounting position) as seen from the actuator mounting surface of the base 20.

In the controller 61 of the first embodiment, travel on a horizontal plane is assumed, so it is assumed that the inclination of the base coordinate system and the inclination of the world coordinate system are equal. In the second embodiment, these may differ, so a block for coordinate conversion between the world coordinate system and the base coordinate system is added to the command calculation. The inclination of the base in the world coordinate system can be measured from the inclination sensor 90 installed on the base 20, making it possible to calculate the coordinate conversion.

The difference between the second embodiment (FIG. 7) and the first embodiment ( ^FIG _{. 3} ) is ^{that the tilt commands of the base coordinate system [S Bx cmd} _, ^S _By The reason is that a coordinate conversion unit 80 that converts to ^cmd ] has been added.

"(Tilt command of the controlled object 40 in the world coordinate system [S _Wx ^cmd , S _Wy ^cmd ]) = (Inclination of the base in the world coordinate system [S _Wx ^B , S _Wy ^B ]) + (Base coordinates The tilt command for the controlled object 40 in the base coordinate system [S _Bx ^cmd , S _By ^cmd ]) holds true, but the tilt command for the controlled object 40 in the base coordinate system [S _Bx ^cmd , S By cmd ]) is modified from this. _By ^cmd ])=(Inclination command of the controlled object 40 in the world coordinate system [S _Wx ^cmd , S _Wy ^cmd ]) - (Inclination of the base in the world coordinate system [S _Wx ^B , S _Wy ^B ]) The "tilt command of the controlled object 40 in the base coordinate system [S _Bx ^cmd , S _By ^cmd ]" is calculated using the formula. Since the slope needs to be converted to an angle and then the difference is taken, specifically

The tilt command in the base coordinate system can be calculated as follows.

However, in equation (7), S _Bx ^cmd is the lateral tilt command of the controlled body 40 in the base coordinate system, S _By ^cmd is the tilt command in the traveling direction of the controlled body 40 in the base coordinate system, S _Wx ^cmd is the lateral tilt command of the controlled body 40 in the world coordinate system, S _Wy ^cmd is the tilt command in the traveling direction of the controlled body 40 in the world coordinate system, S _Wx ^B is the lateral tilt of the controlled body 40 in the world coordinate system detected by the tilt sensor 90, and S _Wy ^B is the tilt in the traveling direction of the controlled body 40 in the world coordinate system detected by the tilt sensor 90.

As described above, according to the second embodiment, by using the tilt information from the tilt sensor 90, it is possible to control the tilt of the controlled object 40 even when the base 20 mounted on the running object (10) tilts. For example, the tilt of the controlled object 40 can be kept horizontal even when the base tilts due to running on a slope. Note that the tilt can be set not only to zero (horizontal), but also to a constant tilt so that the load on the controlled object 40 does not shift when turning.

Figure 8 shows the results of an operation simulation of Example 2. In Figure 8, a cart is used as the controlled object 40, and the tilt of the cart in the traveling direction x and the tilt of the cart in the lateral direction y are shown when the following operation is simulated.

(1) Extend the output shaft upward with a constant actuator torque (small torque), and the upper part of the actuator contacts the trolley (0-10 s).

(2) The actuator length for the maximum rotation angle is controlled as the target value, aiming to keep the cart horizontal (horizontal control) (10s-20s).

(3) AGV10 accelerates at 1 m/s2 for ¹ s, with a speed of 1 m/s (20 s - 21 s). This acceleration causes the cart to tilt in the direction of travel x.

(4) Set the steering to π/6 rad (AGV steering) (25s-). The centrifugal force of this steering causes the cart to tilt sideways in the y direction.

The technique in Example 2 makes it easy to adjust the gain, and it is possible to achieve the operation of "lifting → horizontal control → acceleration → steering" as shown in Figure 8.

REFERENCE SIGNS LIST 10...automated guided vehicle 20...base 31-34...first to fourth actuators 40...controlled object 61...controller 62...command value generating section 63, 65...variable conversion section 64...position controller 64a, 71...subtractor 70...motor driver 72...coefficient assigning section 80...coordinate conversion section 90...tilt sensor

Claims (4)

A base mounted on a movable traveling body;
First to fourth actuators are respectively installed at the four corners of the base, and the output shafts of the actuators are configured to be movable in a direction perpendicular to a surface on which the actuators are installed on the base ;
a controlled body disposed opposite to a tip end of each of the output shafts of the first to fourth actuators;
a position control unit that extends the first to fourth actuators by a force sufficiently smaller than the load of the controlled body, and controls the position of each of the output shafts of the first to fourth actuators while controlling the inclination of the controlled body after the tip of the output shaft of each actuator comes into contact with the controlled body and stops;
The position control unit is
a command value generating unit that converts the center height command of the controlled object and the tilt command of the controlled object into a mode position command using the following equations (1), (2), and (3);

(where x ₁ to x ₄ are the positions of the tips of the output shafts of the first to fourth actuators in the controlled body, X ₁ is a mode variable corresponding to the elevation of the controlled body and is defined as X ₁ = (x ₁ + x ₂ + x ₃ + x ₄ )/4, X ₂ is a mode variable corresponding to the inclination of the controlled body in the lateral direction (the direction of rotation about the x-axis as the axis of rotation) and is defined as X ₂ = (x ₁ - _{x 2} + x ₃ - x ₄ )/4 and is proportional to the lateral inclination S _x , X ₂ = (d ₁₂ /2) S _x (d ₁₂ is the distance between the tip of the output shaft of the first actuator and the tip of the output shaft of the second actuator; the left-right distance between the actuators), and X ₃ is a mode variable corresponding to the inclination of the controlled body in the travel direction (the direction of rotation about the y-axis as the axis of rotation) and X ₃ = (x ₁ + x ₂ - x ₃ - x ₄ )/4 and is proportional to the inclination S _y in the traveling direction, X ₃ = (d ₁₃ /2) S _y (d ₁₃ is the distance between the tip of the output shaft of the first actuator and the tip of the output shaft of the third actuator; actuator front-to-rear distance), X ₄ is a mode variable corresponding to the distortion of the controlled body, H ^cmd is a center height command of the controlled body, S _x ^cmd is a lateral (relative to the x-axis) inclination command of the controlled body, S _y ^cmd is a inclination command in the traveling direction (relative to the y-axis) of the controlled body, and X ₁ ^cmd to X ₄ ^cmd are position command values of the modes).
a position controller that uses equation (4) to determine a modal force reference value based on the modal position command converted by the command value generating unit and a modal response value obtained by variable-converting a position response value of an output shaft of each actuator resulting from performing position control on the first to fourth actuators;

(where C _PM1 to C _PM4 are the characteristics of the position controller, X ₁ ^cmd to X ₄ ^cmd are the position command values of the modes, X ₁ ^res to X ₄ ^res are the response values of the modes, and F ₁ ^ref to F ₄ ^ref are the force reference values of the mode variables).
a variable conversion unit that converts the force reference value of the mode obtained by the position controller into force reference values of the output shafts of the first to fourth actuators using equation (5);

(where T ^-1 is the inverse matrix of the transformation matrix)
A lifting/tilting control device for an automated guided vehicle comprising : The position control unit is
2. The lifting/tilt control device for an automated guided vehicle according to claim 1, characterized in that when there is no load on the controlled object, equal forces are applied to the first to fourth actuators to extend each output shaft, and when the tip of the output shaft of each actuator comes into contact with the controlled object and stops, a deviation from the average length of the output shaft of the actuators is stored, and when the load is transported, the deviation is added to the position response value of the output shaft of each actuator.
The position control section includes:
Calculating the position L of the output shaft of the actuator when the tip of the output shaft of the first to fourth actuators contacts the controlled object using equation (6),

(However, f ₀ ^ref is the output shaft force reference value when no force is applied to each actuator, k is the elastic coefficient of the actuator, and L ₀ is the natural length when no force is applied to each actuator.)
3. The automatic guided vehicle elevation/inclination control device according to claim 1 or 2 , wherein the calculated position L is applied to x ₁ to x ₄ of the equation (1). comprising a tilt sensor installed on the base;
The position control unit includes a coordinate conversion unit that calculates a tilt command in the base coordinate system by calculating the following equation (7), and converts the determined tilt command in the base coordinate system into the command value. The lifting/tilting device for unmanned transportation according to any one of claims 1 to 3 , wherein the generating unit generates a tilting command for the controlled object.

(However, S _Bx ^cmd is a command to tilt the controlled object in the horizontal direction in the base coordinate system, S _By ^cmd is a tilt command in the direction of movement of the controlled object in the base coordinate system, and S _Wx ^cmd is a command to tilt the controlled object in the direction of movement in the base coordinate system. S _Wx ^B is the command to tilt the controlled object in the lateral direction in the world coordinate system, S Wx B is the command to tilt the controlled object in the direction of movement in the world coordinate system, and S _Wx ^B is the command to tilt the controlled object in the world coordinate system in the world coordinate system. (S _Wy ^B is the inclination in the traveling direction of the controlled object in the world coordinate system detected by the inclination sensor)

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