WO2021153411A1

WO2021153411A1 - Moving trolley

Info

Publication number: WO2021153411A1
Application number: PCT/JP2021/002023
Authority: WO
Inventors: 厚太鍋嶌; 悠輔田中
Original assignee: 株式会社ＰｒｅｆｅｒｒｅｄＮｅｔｗｏｒｋｓ
Priority date: 2020-01-27
Filing date: 2021-01-21
Publication date: 2021-08-05
Also published as: JPWO2021153411A1

Abstract

A moving trolley having at least one of wheels and endless tracks. The moving trolley includes: a measurement unit for measuring information about force that is received by the moving trolley from a vehicle support surface of the moving trolley via the wheels or the endless tracks; a calculation unit for calculating an index of stability that is obtained on the basis of the information about the force measured by the measurement unit and positional information about the wheels or the endless tracks relative to the vehicle support surface; and a control unit for controlling a movement of the moving trolley on the basis of the calculated index.

Description

Mobile trolley

This disclosure relates to a mobile trolley.

A mobile trolley that has multiple wheels or tracks and can move autonomously is known. Various controls are applied to improve the convenience of such a mobile trolley. For example, Patent Document 1 proposes a mobile trolley capable of moving the trolley body in an arbitrary direction on a floor contact surface while maintaining the posture of the trolley body at an arbitrary posture angle.

Japanese Unexamined Patent Publication No. 2010-76630

When applying such a mobile trolley to a human coexistence environment, further improvement in stability is required.

The purpose of this disclosure is to provide a mobile trolley that can improve stability.

The mobile trolley according to one aspect of the embodiment of the present invention is a mobile trolley having at least one of a wheel and an endless track, and is said to be from the vehicle support surface of the moving trolley via the wheel or the endless track. An index of stability obtained based on a measuring unit that measures information on the force received by the moving carriage, information on the force measured by the measuring unit, and position information on the wheel or the endless track with respect to the vehicle support surface. A calculation unit for calculating the above, and a control unit for controlling the operation of the mobile trolley based on the calculated index.

According to the present disclosure, it is possible to provide a mobile trolley that can improve stability.

A plan view showing a schematic configuration of a mobile carriage according to an embodiment. Side view of the mobile trolley shown in FIG. Perspective view showing an example of the installation mode of the force sensor Functional block diagram of the controller according to the embodiment Controller hardware configuration diagram Flowchart of operation control of mobile trolley using CoP according to the embodiment Schematic diagram showing the positional relationship between each wheel of the mobile trolley and CoP Schematic diagram showing the schematic configuration of the first modification Schematic diagram showing the schematic configuration of the second modification

Hereinafter, embodiments will be described with reference to the attached drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals as much as possible in each drawing, and duplicate description is omitted.

In the following description, the x direction, the y direction, and the z direction are perpendicular to each other. The x and y directions are horizontal and the z direction is typically vertical. The x direction is the front-rear direction of the moving carriage 1. The y direction is the left-right direction of the moving carriage 1. Further, in the following, for convenience of explanation, the z positive direction side may be expressed as the upper side and the z negative direction side may be expressed as the lower side.

FIG. 1 is a plan view showing a schematic configuration of the mobile carriage 1 according to the embodiment. FIG. 2 is a side view of the moving carriage 1 shown in FIG. 1, and is a schematic view showing the positional relationship between the wheels 2, the force sensor 4, and the base 5.

The mobile trolley 1 according to the embodiment is a device that can autonomously move, for example, by loading a load or mounting a device such as a robot arm. Further, when a device such as a robot arm is mounted, the mobile trolley 1 is a device capable of driving the mounted device to execute various tasks. As shown in FIGS. 1 and 2, the mobile carriage 1 includes a plurality of wheels 2, a plurality of force sensors 4 (measurement units), a base 5, and a controller 10. In the example shown in FIG. 1, the moving carriage 1 advances in the x positive direction side and retreats in the x negative direction side.

In the present embodiment, the mobile carriage 1 includes four

wheels

2A, 2B, 2C, and 2D as a plurality of wheels 2. Of the wheels 2, two

wheels

2A and 2B are arranged on the vehicle body rear side (x negative direction side), and the other two

wheels

2C and 2D are arranged on the vehicle body front side (x positive direction side). Further, the two

wheels

2A and 2B on the rear side of the vehicle body are driving wheels, and

actuators

3A and 3B for supplying driving force to the

respective wheels

2A and 2B are connected.

Actuators

3A and 3B include a power source such as a motor.

The number of wheels 2 included in the mobile carriage 1 is not limited to four, and a plurality of wheels 2 may be provided. Preferably, the number of wheels 2 is at least three, and these wheels 2 have a support polygon of the mobile carriage 1 (support area of the mobile carriage 1) when the contact points with the floor (vehicle support surface of the mobile carriage 1) are connected. ) Is formed. Further, the number of drive wheels is not limited to two, and at least one of the plurality of wheels 2 may be a drive wheel. Also, the wheels may be replaced with tracks.

The plurality of force sensors 4 measure the floor reaction force received by each of the plurality of wheels 2. In the present embodiment, the mobile carriage 1 includes four

force sensors

4A, 4B, 4C, and 4D as a plurality of force sensors 4. The

force sensors

4A, 4B, 4C, and 4D are installed in association with the four

wheels

2A, 2B, 2C, and 2D, respectively, and the floor reaction force received by the

wheels

2A, 2B, 2C, and 2D (at least in the z direction of the floor reaction force). (Vertical direction) component) is measured. The plurality of force sensors 4 function as a measuring unit that measures information on the force received by the moving carriage 1 from the vehicle support surface of the moving carriage 1 via the wheels 2 (or endless track).

That is, in the present embodiment, the number of the plurality of force sensors 4 is the same as the number of the wheels 2 included in the moving carriage 1. Even with a configuration including a number of force sensors smaller than the number of wheels 2, it is possible to calculate the force received by the moving carriage 1 from the contact surface of the wheels 2 (the vehicle supporting surface of the moving carriage 1). Such a configuration will be described later with reference to FIGS. 8 and 9.

In the present embodiment, as shown in FIG. 2, for example, in the mobile carriage 1, a base 5 for installing luggage, devices, and the like is laminated above each wheel 2. Then, the plurality of force sensors 4 are installed between the wheel 2 associated with measuring the floor reaction force and the base 5. In this configuration, each of the plurality of force sensors 4 is a uniaxial compressive force sensor, and the plurality of force sensors 4 are installed so that their detection directions are in the vertical direction (z direction). As a result, the plurality of force sensors 4 can measure the floor reaction force (force shown by f1 and f2 in FIG. 2) applied to each wheel 2, respectively. As the force sensor 4, a tensile compression sensor capable of detecting both a tensile force and a compressive force may be used.

It is preferable that the plurality of force sensors 4 are arranged directly above each of the rotation axes (axle 6D, see FIG. 6) of each wheel 2. As a result, each force sensor 4 can detect a value closer to the floor reaction force actually received by each wheel 2. Further, each force sensor 4 can be made less likely to receive a moment due to the floor reaction force received by each wheel 2.

FIG. 3 is a perspective view showing an example of the installation mode of the force sensor 4. As shown in FIG. 3, the component group that holds the wheel 2 has a structure that can be rotated by the shaft 6A held by the bearing 6G. For the bearing 6G of the shaft 6A, it is preferable to use a sliding bearing instead of a rolling bearing for simplification of the structure. A load cell (force sensor 4) and a seat 6E are arranged directly above the axle 6D of the wheel 2, and the output of the load cell 4 changes depending on the reaction force received from the seat 6E. If the seat 6E is deformed due to an impact or the like, the contact state with the load cell 4 changes, and the output reproducibility of the load cell 4 is lost. Therefore, it is desirable to use a steel material instead of an aluminum material for the seat 6E.

If the reaction force from the floor is not applied to the wheel 2, there is a gap between the load cell 4 and the seat 6E, and the wheel 2 rotates downward due to gravity. Therefore, the stopper 6F is used to restrain the rotation. This prevents the wheel 2 from falling.

The shaft 6A has an axial direction in the y direction like the axle 6D, and is arranged parallel to the axle 6D. Both the shaft 6A and the axle 6D are rotatably connected to the member 6B whose longitudinal direction is the x direction. A receiving seat 6E is installed directly above the axle 6D on the upper surface of the member 6B. Similar to the member 6B, the member 6C having the x direction as the longitudinal direction is arranged above the member 6B, and the force sensor 4 (load cell) is installed at a position on the lower surface of the member 6C facing the receiving seat 6E. .. The member 6C is fixed to, for example, the base 5. As shown in FIG. 3, for example, the stopper 6F has a convex portion 6F1 projecting upward from the upper surface of the member 6B and a concave portion 6F2 provided on the member 6C into which the convex portion 6F1 is slidably fitted. It is configured to prevent the member 6B from rotating downward about the shaft 6A when the wheel 2 has no load.

The holding structure of the wheel 2 illustrated in FIG. 3 has the same structure for the

driving wheels

2A and 2B and the driven

wheels

2C and 2D.

Returning to FIG. 1, the controller 10 controls the overall operation of the mobile carriage 1. In the present embodiment, the controller 10 acquires the measured values of the floor reaction forces received by the four

wheels

2A, 2B, 2C, and 2D from the four

force sensors

4A, 4B, 4C, and 4D, and these acquired floor reaction forces. And, an index obtained based on the wheel position information, specifically, CoP (Center of Pressure) is calculated. CoP is the position coordinate of the pressure center of the floor reaction force received by each of the plurality of

wheels

2A, 2B, 2C, and 2D (see coordinate P in FIG. 7). In CoP, the total of the moments generated by each floor reaction force, gravity, etc. becomes zero. That is, in the mobile carriage 1 provided with the plurality of wheels 2, the CoP coincides with the so-called ZMP (Zero Moment Point). In the present disclosure, CoP is an index (numerical information) used for calculating the stability of the mobile carriage 1.

The controller 10 can execute an operation of evaluating the stability of the mobile carriage 1 based on the calculated CoP. Further, the controller 10 outputs a control command to the

actuators

3A and 3B of the

drive wheels

2A and 2B and the actuators such as the in-vehicle robot hand (end effector), and the position of the CoP can be more stabilized by the moving carriage 1. It is possible to execute an operation (stabilization control) that causes a transition to.

FIG. 4 is a functional block diagram of the controller 10 according to the present embodiment. As shown in FIG. 4, the controller 10 includes a floor reaction force calculation unit 11 (measurement unit), a CoP calculation unit 12, a stability evaluation unit 13, and a stabilization control unit 14 with respect to the above-mentioned functions.

The floor reaction force calculation unit 11 calculates the floor reaction force received by the four

wheels

2A, 2B, 2C, and 2D based on the output signals of the four

force sensors

4A, 4B, 4C, and 4D. The floor reaction force calculation unit 11 is a measuring unit that measures information on the force received by the moving carriage 1 from the vehicle support surface (contact surface of the wheels 2 with the ground) of the moving carriage 1 via the wheels 2 (or endless track). Function.

The CoP calculation unit 12 calculates CoP based on the floor reaction force of each

wheel

2A, 2B, 2C, 2D calculated by the floor reaction force calculation unit 11 and the position information of each

wheel

2A, 2B, 2C, 2D. do.

The stability evaluation unit 13 calculates the current stability (stability index) of the mobile trolley 1 based on the support polygon A (see FIG. 7) of the CoP and the mobile trolley 1 calculated by the CoP calculation unit 12. .. Further, the mobile trolley 1 is provided with a notification device 15 such as a display screen and a microphone, and notifies the user of the mobile trolley 1 of the evaluation result by the stability evaluation unit 13 via the notification device 15, thereby causing the mobile trolley 1 to notify the user. The configuration may be such that the stability can be monitored by the user. The stability evaluation unit 13 calculates a stability index obtained based on the force information measured by the floor reaction force calculation unit 11 and the position information of the wheel 2 (or track) with respect to the vehicle support surface. Functions as a department. The stability evaluation unit 13 also functions as a control unit that controls the operation of the mobile carriage 1 based on the calculated stability index.

The stabilization control unit 14 controls the

actuators

3A and 3B so that the mobile carriage 1 is stabilized based on the CoP calculated by the CoP calculation unit 12. The stabilization control unit 14 may control the

actuators

3A and 3B based on the stability (an index of the current stability of the mobile carriage 1) calculated by the stability evaluation unit 13. The stabilization control unit 14 functions as a control unit that controls the operation of the mobile carriage 1 based on the calculated stability index.

The controller 10 only needs to be able to control some operation of the mobile carriage 1 by using at least the CoP calculated by the CoP calculation unit 12, and includes only one of the stability evaluation unit 13 and the stabilization control unit 14. It may be configured. Specific examples of stability evaluation and stabilization control will be described later with reference to the flowcharts of FIG. 6 (particularly steps S03 to S05).

FIG. 5 is a hardware configuration diagram of the controller 10. As shown in FIG. 5, the controller 10 physically includes a CPU (Central Processing Unit) 101, a RAM (Random Access Memory) 102 and a ROM (Read Only Memory) 103 as main storage devices, and a keyboard as an input device. It can be configured as a computer system including an input device 104 such as a mouse, an output device 105 such as a display, a communication module 106 which is a data transmission / reception device such as a network card, and an auxiliary storage device 107.

Each function of the controller 10 shown in FIG. 4 is input to the communication module 106 under the control of the CPU 101 by loading predetermined computer software (operation control program of the mobile carriage) on the hardware such as the CPU 101 and the RAM 102. This is realized by operating the device 104 and the output device 105, and reading and writing data in the RAM 102 and the auxiliary storage device 107. That is, by executing the operation control program of the mobile trolley according to the present embodiment on the computer, the controller 10 has the floor reaction force calculation unit 11, the CoP calculation unit 12, the stability evaluation unit 13, and the stabilization control in FIG. It functions as a unit 14.

Further, each function of the controller 10 may be a circuit composed of an analog circuit, a digital circuit, or an analog / digital mixed circuit. Further, a control circuit for controlling each function may be provided. The implementation of each circuit may be by ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or the like.

At least a part of each function of the controller 10 may be configured by hardware, or may be configured by software and executed by a CPU or the like by information processing of the software. When composed of software, the controller 10 and a program that realizes at least a part of the functions may be stored in a storage medium such as a flexible disk or a CD-ROM, read by a computer, and executed. .. The storage medium is not limited to a removable one such as a magnetic disk or an optical disk, and may be a fixed storage medium such as a hard disk device or a memory. That is, information processing by software may be concretely implemented using hardware resources. Further, the processing by software may be implemented in a circuit such as FPGA and executed by hardware such as a processor. The job may be executed by using an accelerator such as a GPU (Graphics Processing Unit), for example.

For example, the computer can be used as the device of the above embodiment by reading the dedicated software stored in the storage medium that can be read by the computer. The type of storage medium is not particularly limited. Further, the computer can be used as the device of the above-described embodiment by installing the dedicated software downloaded via the communication network on the computer. In this way, information processing by software is concretely implemented using hardware resources. Note that one or more hardware such as a memory, a processor, and a computer may be provided.

The controller 10 may be mounted on the mobile trolley 1, or may be configured to be connected to the mobile trolley 1 by wire or wirelessly at a position distant from the mobile trolley 1.

FIG. 6 is a flowchart of operation control of the mobile carriage 1 using CoP according to the embodiment. The flowchart shown in FIG. 6 is implemented by the controller 10.

In step S01, the floor reaction force calculation unit 11 calculates the floor reaction force of each wheel 2A to 2D based on the measured values of the force sensors 4A to 4D. The floor reaction force calculation unit 11 outputs the detected values of the force sensors 4A to 4D to the CoP calculation unit 12 as the floor reaction force of each wheel 2A to 2D.

In step S02, the CoP calculation unit 12 calculates the CoP of the moving carriage 1 based on the floor reaction force of each wheel 2A to 2D. The CoP calculation unit 12 can calculate the CoP coordinates P = (xp, yp) using, for example, the following equation (1). In the equation (1), the subscripts associated with the wheels 2A to 2D are i, the floor reaction force of the wheels 2A to 2D is f_i, and the plane position coordinates of the wheels 2A to 2D are p_i = (x_i, y_i).

FIG. 7 is a schematic view showing the positional relationship between each wheel 2A to 2D of the mobile carriage 1 and CoP. As shown in FIG. 7, the coordinates P = (xp, yp) of CoP are arranged in the support polygon A formed by connecting the ground contact points 7A to 7D of the wheels 2A to 2D in a plan view. It can be said that the closer the coordinate P of the CoP is to the position G of the center of gravity of the support polygon A, the more stable the moving carriage 1 is and the less likely it is to tip over. The support polygon A is calculated based on, for example, the position information of the wheel 2 (or track) with respect to the vehicle support surface.

Returning to FIG. 6, after that, one or both of the stability evaluation (steps S03 and S04) and the stabilization control (step S05) are performed using the CoP calculated in step S02.

In step S03, the stability evaluation unit 13 evaluates the stability of the mobile carriage 1 based on CoP. The stability evaluation unit 13 evaluates the stability by observing, for example, the position of the CoP calculated by the CoP calculation unit 12 in the support polygon A. For example, as shown in FIG. 7, it can be evaluated that the current stability of the mobile trolley 1 is lower as the calculated position of CoP is closer to the side of the support polygon A (the possibility that the mobile trolley 1 falls is relatively low). expensive). Further, it can be evaluated that the closer the calculated position of CoP is to the center of gravity G of the support polygon A, the higher the current stability of the mobile carriage 1 (the possibility that the mobile carriage 1 falls is relatively low). In this way, the stability of the moving carriage 1 can be quantified based on the positional relationship between the coordinates P of CoP and the supporting polygon A. For example, the stability evaluation unit 13 calculates the distance between CoP in the support polygon A and each side of the support polygon A as stability (an index of stability of the moving carriage 1), and the distance is less than a predetermined value. Evaluate whether or not. When the distance is less than a predetermined value, it can be judged that the stability is low.

The reason why stability can be evaluated by CoP will be further explained. When CoP is on the side of the supporting polygon A, all of the total weight is hung on the wheels (for example, wheel 2A) constituting the side. This is a state in which the floor reaction force of the wheels on the opposite side (for example, wheels 2D) is 0, and the wheels 2D are starting to float. If the CoP is from the inside to the outside of the support polygon A and it does not stop, it will fall around the wheel 2A. On the other hand, it can be said that the closer the CoP is to the center of the supporting polygon A, the higher the stability. In addition, since the CoP position P fluctuates when there is a disturbance, when the load balance changes, or when an inertial force due to acceleration / deceleration or turning is applied, stability is achieved by monitoring the CoP position P. Can be evaluated.

The stability evaluation unit 13 can output the evaluation result to the in-vehicle notification device 15. In this case, in step S04, the notification device 15 notifies the user of the stability of the mobile trolley 1 by using an arbitrary notification method such as an image or sound. Further, in step S04, the notification device 15 may visually display the positional relationship between the coordinates P of CoP and the support polygon A as shown in FIG. 7. The stability evaluation unit 13 may transmit the evaluation result to an external device of the mobile carriage 1.

Further, in steps S03 and S04, the stability evaluation unit 13 detects that the corresponding wheel 2 is floating from the ground when the detection value is zero among the plurality of force sensors 4A to 4D. The processing for notifying may also be carried out. In addition, considering the duration during which the detection value of the force sensor 4 becomes zero, whether the corresponding wheel 2 has been removed or is temporarily floating, or whether it hits the bottom (under the chassis to which the wheel 2 is attached). It can be detected whether the road surface is in contact with the vehicle.

Further, the CoP calculation unit 12 calculates another index for calculating the stability in addition to the CoP obtained based on the floor reaction forces of the plurality of wheels 2, and the stability evaluation unit 13 calculates this other index. The stability may be evaluated based on the above. For example, based on the inertial parameters (mass, center of gravity position, moment of inertia, etc.) of the moving trolley 1 and the load of the moving trolley 1, the inertial force obtained from the acceleration / deceleration or turning information that the moving trolley 1 intends to execute is obtained. The added virtual CoP may be calculated as another index. That is, this virtual CoP is based on information on the force received by the mobile carriage 1 from the vehicle support surface, the inertial parameters of the load of the mobile carriage 1, and the inertial force generated by the planned operation of the mobile carriage 1. It is calculated. These inertial parameters may be calculated in advance using design values or based on the floor reaction forces of each wheel 2A-2D. In this case, when the distance between the calculated position of the virtual CoP and the side of the support polygon A is less than a predetermined value, the stability evaluation unit 13 controls stabilization so as not to accelerate / decelerate or turn. Limits can be given to unit 14.

Further, in the case where the mobile trolley 1 includes a manipulator and a hand mounted on the tip of the manipulator and gripping an object, for example, the mobile trolley 1 and the manipulator, the hand, and an object gripped by the hand. Based on the inertial parameters (mass, center of gravity position, moment of inertia, etc.), the inertial force obtained from the acceleration / deceleration or turning information that the moving carriage 1 intends to execute, and the acceleration / deceleration information that each axis of the manipulator intends to execute. The virtual CoP in consideration of the reaction force obtained from the above may be calculated as an index for calculating the stability. That is, this virtual CoP contains information on the force that the mobile carriage 1 receives from the vehicle support surface, the inertial parameters of the load of the mobile carriage 1, the inertial force generated by the planned operation of the mobile carriage 1, and the manual. It is calculated based on the reaction force that the moving carriage 1 receives from the manipulator with the operation of the purator. These inertial parameters may be calculated using design values or based on, for example, the floor reaction forces of a plurality of wheels 2, the position information of each wheel 2, and the attitude of the manipulator. The inertial parameters of the manipulator, the hand, and the gripping object change according to the posture of the manipulator and the shape of the attached hand and the gripping object. Therefore, based on the method of the present embodiment, the inertial parameters of the manipulator and the like can be estimated by using the information such as the attitude of the manipulator and the measured value of the force sensor 4. Further, if the inertial parameter can be estimated, it can be used for estimating the external force applied to the manipulator, and the reaction force received from the manipulator by the moving carriage 1 due to the operation of the manipulator can be estimated.

Further, in the case where the mobile trolley 1 is provided with a trolley portion on which a plurality of wheels 2 are installed or an inclinometer installed on a base portion 5 installed above the trolley portion, the output value of the inclinometer is set to the output value of the inclinometer. Information on the degree of inclination of the ground may be acquired accordingly, and a predetermined value used for stability evaluation may be adjusted according to the degree of inclination. With this configuration, it is possible to evaluate the stability more suitable for the driving environment. Further, by using the information on the degree of inclination, the total weight and the inertial parameters of the moving trolley 1 can be calculated even when the moving trolley 1 is traveling on the slope. Further, by using the information on the degree of inclination, it is possible to easily filter the value of the force sensor 4 so as not to be affected by the uneven road surface.

Based on the stability evaluation result notified via the notification device 15, the user of the mobile trolley 1 manually stops the operation of the mobile trolley 1 or slows down the operation in order to avoid the mobile trolley 1 from tipping over, for example. You can perform operations. Alternatively, it is possible to perform work such as transshipping the luggage loaded on the mobile carriage 1 so as to improve the stability.

Further, in steps S03 and S04, the stability evaluation unit 13 may output an alert when the calculated CoP coordinates and the distance between each side of the support polygon A are less than a predetermined value.

In step S05, the stabilization control unit 14 executes stabilization control of the mobile carriage 1 based on CoP. As shown in FIG. 7, for example, when the position of CoP is close to the side of the support polygon A, the stabilization control unit 14 shifts the position of CoP in the direction of the center of gravity G of the center of the support polygon A. The operation of the moving carriage 1 can be controlled by adjusting the control commands to the

drive wheels

2A and 2B so that the stability is improved. That is, the stabilization control unit 14 controls the operation of the moving carriage 1 so that the calculated CoP coordinates and the distance between each side of the support polygon A do not fall below a predetermined value.

When the mobile carriage 1 is configured to include a manipulator, the stabilization control unit 14 determines that the distance between the calculated CoP coordinates and each side of the support polygon A does not fall below a predetermined value. It may be configured to control the operation.

Further, the stabilization control unit 14 receives the detection value of the compressive force sensor 4 from the vehicle support surface based on the floor reaction force of the plurality of wheels 2 or while observing the value of the force sensor 4. It is also possible to control the torque of each wheel 2 so that the frictional force of each wheel 2 with the vehicle support surface is within an appropriate range). This makes it possible to cope with the change in frictional force in proportion to the normal force.

Further, as described above, the CoP calculation unit 12 obtains the inertial force obtained from the acceleration / deceleration or turning information that the mobile carriage 1 intends to execute based on the inertial parameters of the mobile carriage 1 and the load of the mobile carriage 1. When the added virtual CoP is calculated as an index for calculating the stability, the stabilization control unit 14 can also perform stabilization control based on the calculated virtual CoP. This inertial parameter can also be calculated in advance based on the floor reaction force of each wheel 2A to 2D. As a result, for example, when the load moves while driving, or when a part of the load is unloaded from the trolley, it is unknown how the load is placed or what is placed, or when the load changes on the way. However, acceleration / deceleration, rotation speed, and radius of gyration can be adjusted so that the inertial force is within an appropriate range. In other words, the cruising speed can be maximized while guaranteeing stability.

Further, when the calculated CoP coordinates and the distance between each side of the support polygon A are less than a predetermined value, the stabilization control unit 14 at least stops, suppresses acceleration / deceleration, or expands the turning radius. It may be configured to perform one.

When the process of step S04 or S05 is completed, this control flow ends.

As described above, in the mobile carriage 1 of the present embodiment, the CoP calculation unit 12 of the controller 10 obtains a numerical value based on the floor reaction forces of the plurality of wheels 2 measured by the plurality of force sensors 4 and the position information of the wheels 2. CoP is calculated as information, and the stability evaluation unit 13 and the stabilization control unit 14 control the operation of the mobile trolley 1 based on the calculated CoP.

With this configuration, it is possible to control the operation of the mobile carriage 1 based on CoP, which is an index related to stability, and as a result, the stability of the mobile carriage 1 can be improved. With conventional mobile trolleys, there is a risk that stability cannot be ensured by control alone, so physically, such as increasing the ground contact area, increasing the footprint to increase the supporting polygon A, and increasing the weight, etc. There is a tendency to stabilize. On the other hand, in the mobile trolley 1 of the present embodiment, the stability can be sufficiently improved even if the footprint is small or lightweight by controlling the operation of the mobile trolley as described above, so that the stability can be physically improved. It is not necessary to plan, and the physique of the mobile carriage 1 can be reduced in size and weight.

A modified example of the above embodiment will be described with reference to FIGS. 8 and 9. In the above embodiment, the number of the plurality of force sensors 4 is the same as the number of the wheels 2 included in the moving carriage 1, but the configuration including the number of force sensors smaller than the number of the wheels 2 is also included in each wheel. It is possible to calculate the floor reaction force.

FIG. 8 is a schematic diagram showing a schematic configuration of the first modification. As shown in FIG. 8, in the first modification, a base portion 5 on which a plurality of wheels 2 are installed and a main body portion 21 installed above the base portion 5 are provided, and between the base portion 5 and the main body portion 21. One 3-axis force sensor 22 is provided. The 3-axis force sensor 22 measures the compressive force in the z-axis direction and the moments around the x-axis and the y-axis. In the first modification, the detected value of the three-axis force sensor 22 is output as information on the force received by the moving carriage 1. If it is possible to measure at least the three axes of the compressive force in the z direction and the moments in the x direction and the y direction, a multiaxial force sensor having more than the three axes may be used. In the configuration of the first modification, the floor reaction force calculation unit 11 and the CoP calculation unit 12 of the controller 10 can calculate CoP from the detected values of the triaxial force sensor 22. Further, the floor reaction force can be calculated by decomposing the floor reaction forces f1 and f2 of the plurality of wheels 2.

The CoP calculation method in the first modification will be further described. In a configuration using a multi-axial force sensor such as the 3-axial force sensor 22, the CoP calculation unit 12 calculates, for example, the compressive force in the z direction among the detected values of the multi-axial force sensor in the Fz, x-direction, and y-direction moments. Assuming that M_x and M_y are used, respectively, the CoP coordinates p = (p_x, p_y) are calculated by the following equation (2).

FIG. 9 is a schematic diagram showing a schematic configuration of the second modification. As shown in FIG. 9, in the second modification, a base portion 5 on which a plurality of wheels 2 are installed and a main body portion 21 installed above the base portion 5 are provided, and between the base portion 5 and the main body portion 21. Is provided with three uniaxial

compressive force sensors

23A, 23B, 23C, which is less than the number of wheels 2. The three uniaxial

compressive force sensors

23A, 23B, and 23C measure the compressive force in the z direction at each installation position. The three uniaxial

compressive force sensors

23A, 23B, and 23C are not provided at positions corresponding to the wheels 2, and are arranged at substantially equal intervals inside the support polygon A formed by the ground contact points of the wheels 2, for example. Will be done. In the configuration of the second modification, the floor reaction force calculation unit 11 of the controller 10 can calculate CoP from the detected values of the uniaxial

compressive force sensors

23A, 23B, and 23C. Further, the floor reaction force can be calculated by decomposing the floor reaction forces f1 and f2 of the plurality of wheels 2.

As in the configuration in which the

force sensors

22, 23A to 23C are provided in a number smaller than the number of the wheels 2 shown in the first and second modifications, the floor surface of each wheel 2 does not necessarily have to be provided for each wheel 2. The force can be calculated. As a result, even if there are design restrictions such as no space for installing the force sensor around the wheel 2, the number and installation position of the force sensor can be adjusted arbitrarily, so that the adjustment can be performed with a high degree of freedom. The design of the mobile trolley 1 can be facilitated while reducing the size and weight of the mobile trolley 1. In the second modification, the number of uniaxial

compressive force sensors

23A, 23B, 23C may be less than the number of wheels 2, and when the number of wheels 2 is 5 or more, the number of force sensors is 3. The above may be sufficient.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Those skilled in the art with appropriate design changes to these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-mentioned specific examples, its arrangement, conditions, shape, and the like are not limited to those illustrated, and can be changed as appropriate. The combinations of the elements included in each of the above-mentioned specific examples can be appropriately changed as long as there is no technical contradiction.

This international application claims priority based on Japanese Patent Application No. 2020-01526 filed on January 27, 2020, and the entire contents of No. 2020-01526 are incorporated herein by reference.

Claims

A mobile trolley with at least one of wheels and tracks.
A measuring unit that measures information on the force received by the moving carriage from the vehicle support surface of the moving carriage via the wheels or the endless track.
A calculation unit that calculates a stability index obtained based on the force information measured by the measurement unit and the position information of the wheel or the endless track with respect to the vehicle support surface.
A control unit that controls the operation of the mobile trolley based on the calculated index, and
A mobile trolley equipped with.
The measuring unit includes a compressive force sensor, and outputs a detection value of the compressive force sensor as information on the force received by the moving carriage.
The mobile trolley according to claim 1.
The compressive force sensor is provided directly above each axle of the wheel.
The mobile trolley according to claim 2.
With the base on which the wheels or tracks are installed,
It is provided with a main body portion installed above the base portion, and is provided with a main body portion.
The measuring unit includes one multi-axial force sensor provided between the base unit and the main body unit and capable of measuring at least three axes of a compressive force in the z direction and moments in the x and y directions. The detection value of the multi-axial force sensor is output as information on the force received by the moving carriage.
The mobile trolley according to claim 1.
The index is calculated from CoP (Center of Pressure), which is the center of the force that the wheel or the endless track receives from the vehicle support surface, based on the position information of the wheel or the endless track with respect to the vehicle support surface. The distance to each side of the supporting polygon,
Assuming that the detection value of the compressive force sensor is f_i and the plane position coordinates of the compressive force sensor are p_i = (x_i, y_i), the calculation unit calculates the coordinates P of the CoP by the following equation (1). The mobile trolley according to claim 2.
The index is a support calculated from CoP (Center of Pressure), which is the center of pressure that the wheel or track receives from the vehicle support surface, based on the position information of the wheel or track with respect to the vehicle support surface. The distance to each side of the polygon,
Assuming that the compressive force in the z direction is Fz and the moments around the x and y directions are M_x and M_y, respectively, among the detected values of the multiaxial force sensor, the calculation unit uses the following equation (2) to determine the coordinates of the CoP. The mobile trolley according to claim 4, wherein p = (p_x, p_y) is calculated.
The calculation unit includes an inertial parameter of the load calculated in advance based on information on the force received by the mobile carriage, an inertial force obtained from information on acceleration / deceleration or turning that the mobile carriage intends to execute, and the above-mentioned inertial force. The mobile trolley according to claim 5, wherein the CoP is calculated based on the information of the force received by the mobile trolley.
The manipulator mounted on the mobile trolley and
An end effector mounted on the tip of the manipulator to grip an object,
With
The calculation unit
Each link of the manipulator, the end effector, or at least one or more inertial parameters of the object gripped by the end effector.
The inertial force obtained from the acceleration / deceleration or turning information that the mobile trolley intends to execute, and
The reaction force obtained from the acceleration / deceleration information that each axis of the manipulator intends to execute, and
Information on the force received by the mobile trolley and
The mobile trolley according to claim 5, wherein the CoP is calculated based on the above.
An inclinometer installed on a base on which the wheels or tracks are installed, or on a main body installed above the base.
The mobile trolley according to claim 1.
When the distance between the calculated coordinates of the CoP and each side of the supporting polygon falls below a predetermined value, the control unit performs at least one of stopping, suppressing acceleration / deceleration, and expanding the turning radius. conduct,
The mobile trolley according to claim 5.
The control unit detects that the wheel is floating when the detection value of the compressive force sensor is zero.
The mobile trolley according to claim 2.
The control unit outputs an alert when the calculated coordinates of the CoP and the distance between each side of the supporting polygon are less than a predetermined value.
The mobile trolley according to claim 5.
The control unit controls the operation of the moving carriage so that the calculated coordinates of the CoP and the distance between each side of the supporting polygon do not fall below a predetermined value.
The mobile trolley according to claim 5.
The control unit controls the operation of the manipulator so that the calculated coordinates of the CoP and the distance between each side of the supporting polygon do not fall below a predetermined value.
The mobile trolley according to claim 8.
The control unit regards the detection value of the compression force sensor measured by the measurement unit as a reaction force received by the corresponding wheel from the vehicle support surface, and the frictional force of each wheel with the vehicle support surface is generated. Control the torque of each wheel so that it is within the proper range,
The mobile trolley according to claim 2.
It ’s a mobile trolley,
With multiple wheels, including drive wheels,
A sensor that measures the force received by the moving carriage from the vehicle support surface of the moving carriage via the plurality of wheels, and
A controller that calculates the position of the measured center of force and controls the operation of the moving trolley based on the calculated position of the center of force and the support area of the moving trolley.
A mobile trolley equipped with.