JP7283152B2 - Autonomous mobile device, program and steering method for autonomous mobile device - Google Patents

Description

The present invention relates to an autonomous mobile device, a program, and a steering method for an autonomous mobile device.

2. Description of the Related Art Conventionally, automating transportation work in a warehouse by using an automated guided vehicle (AGV), which is an autonomous mobile device, has been widely studied in the world. Specifically, a configuration is already known in which an automatic guided vehicle is provided with a connection mechanism, an object to be conveyed (a basket car) is connected to the automatic guided vehicle, and the object is conveyed within a warehouse.

Patent Literature 1 discloses an automatic transport vehicle that automatically determines and controls a transport route.

Further, Patent Literature 2 discloses a technique for easily and reliably connecting an autonomous mobile device to an object to be conveyed (cargo cart) when automatically connecting the device.

By the way, an automated guided vehicle (AGV), which is an autonomous mobile device, must always steer left and right when tracing and moving on a track, and it traces the track while moving left and right by this steering. In other words, it can be said that the automatic guided vehicle (AGV) always staggers during travel. Further, when the automatic guided vehicle (AGV) is connected to the object to be conveyed (carrying basket) and travels, in other words, when the automatic guided vehicle (AGV) is conveying the object to be conveyed (carrying basket) , resonance occurs at a specific frequency in accordance with the weight of the object to be conveyed (basket cart), and the fluctuation increases at the specific frequency at which this resonance occurs. In particular, when the vehicle travels through narrow passages in a warehouse, for example, the influence of this swaying is great, and if the swaying is large, it becomes difficult to travel through the passages.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to suppress fluctuation during travel of an autonomous mobile device that transports an object to be transported. In particular, it is an object of the present invention to suppress an increase in fluctuation at a specific frequency corresponding to the weight of a load loaded on an object to be conveyed while the object is being conveyed.

In order to solve the above-described problems and achieve the object, the present invention provides an autonomous mobile device for carrying an object to be carried, in which a frequency obtaining means for obtaining a resonance frequency of the object to be carried, and a steering device for steering the autonomous mobile device. A control means for performing steering control by reducing the gain in the frequency range including the resonance frequency from the control signal using a filter that attenuates the control output in the range including the resonance frequency for the control signal that controls the It is characterized by having

ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to suppress the swaying at the time of driving|running|working of the autonomous moving apparatus which conveys a conveying target object. In particular, it is possible to suppress an increase in fluctuation at a specific frequency corresponding to the weight of a load loaded on an object to be conveyed while the object is being conveyed.

FIG. 1 is an explanatory diagram showing a self-propelled robot and a cage carriage in the transport system according to the first embodiment. FIG. 2 is a perspective view showing an example in which an ID panel is arranged on a cart. FIG. 3 is an explanatory diagram showing an example of a distribution warehouse to which the transportation system is supposed to be applied. FIG. 4 is a block diagram showing an example of the hardware configuration of the controller of the self-propelled robot. FIG. 5 is a block diagram showing a functional configuration example exhibited by the controller of the self-propelled robot. FIG. 6 is a diagram showing the configuration of the steering control system. FIG. 7 is a diagram showing an example of frequency characteristics of a controlled object. FIG. 8 is a diagram for explaining control signals for controlling the steering angle. FIG. 9 is a diagram showing the relationship between the weight of the object to be conveyed and the current. FIG. 10 is a diagram showing the relationship between the weight of the object to be conveyed and the current for detection of the fluctuation frequency according to the second embodiment.

Embodiments of an autonomous mobile device, a program, and a steering method for the autonomous mobile device will be described in detail below with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is an explanatory diagram showing a self-propelled robot 1 and a cage carriage 2 in a transport system according to the first embodiment. This embodiment is an automated guided vehicle (AGV) that automatically transports the basket trolley 2 to a desired destination by automatically connecting to and towing a towed trolley such as the basket trolley 2 that is a connection target. ) is applied to an autonomous mobile device.

The self-propelled robot 1 is an autonomous mobile device having a function of automatically connecting to a basket cart 2 on which goods are loaded. As a result, the self-propelled robot 1 does not need to have a structure capable of being loaded, and by pulling the cage carriage 2 with a simple moving device, a large number of objects loaded on the cage carriage 2 can be transported. can.

As shown in FIG. 1, the self-propelled robot 1 includes a robot body 100 as a device body, a magnetic sensor 3, a controller 4 as a detection device, a power source (battery) 6, a power motor 7, a motor driver 8, a first range sensor 9, coupling device 10, drive wheel 71, driven wheel 72, and the like. Range sensor 9 recognizes the surrounding environment of self-propelled robot 1 .

In the transport system of the present embodiment, a magnetic tape, which is a guide tape, is placed on the floor of a route on which the self-propelled robot 1 can travel, and the magnetic sensor 3 is used to detect the magnetic tape, thereby allowing the self-propelled robot 1 to travel. It can be recognized that it is located on a possible route. The guidance method for installing the tape on the floor is not limited to the configuration using the magnetic tape (magnetic type), but may be the configuration using the optical tape (optical type). When using an optical tape, a reflective sensor, an image sensor, or the like can be used instead of the magnetic sensor 3 .

Further, in the transport system of this embodiment, it is possible to autonomously travel by recognizing its own position by collating the two-dimensional or three-dimensional map with the detection result of the range sensor 9 . The range sensor 9 is a scanning laser distance sensor (laser range finder (LRF)) that irradiates an object with laser light and measures the distance to the object from the reflected light. Henceforth, the ranging sensor 9 may be described as LRF9.

In addition to the laser range finder (LRF), a stereo camera, a depth camera, etc. can also be used as a sensor for recognizing the self position by matching the detection result with a two-dimensional or three-dimensional map.

In the self-propelled robot 1, the controller 4 controls the driving of the power motor 7 via the motor driver 8 based on the detection results of the magnetic sensor 3 and the range sensor 9, and the power motor 7 rotates the drive wheels 71. As a result, the self-propelled robot 1 runs autonomously.

As shown in FIG. 1, the basket truck 2 includes a bottom plate 22 that holds the basket portion 20, casters 23 arranged at the four corners of the rectangular bottom plate 22, and identification members arranged on the side surfaces of the basket portion 20. and an ID panel 21 .

An ID panel 21 on which a recognition marker is displayed is attached to the basket truck 2 placed at a predetermined place. For the marker, the identification number information (ID information) of the cage cart 2, the destination information such as the transportation position, and the priority information of transportation are coded using retroreflective tape 21b (see FIG. 2) or the like, which is a band-shaped member. ing. The identification number information (ID information) of the cart 2 can be recognized by referring to a table or the like.

The self-propelled robot 1 is equipped with a marker reader. The marker reader comprises a range sensor 9 as ID recognition means and a decoding section. In this embodiment, the controller 4 functions as a decoding section. The controller 4 recognizes the marker code from the detection result of the range sensor 9 . The decoding unit of the controller 4 decodes the code information of the recognized marker to obtain identification number information, transport destination information, and priority information of the cart 2 .

In this embodiment, a retroreflective tape 21b is used as a marker installed on the cart 2. As shown in FIG. The self-propelled robot 1 reads using a range sensor 9 such as a laser range finder (LRF) that obtains the distance to the surrounding environment. The controller 4 calculates the position coordinates of the ID panel 21 from distance information between the ID panel 21 whose position is recognized by the range sensor 9 and the range sensor 9 . Using the calculated positional coordinates of the ID panel 21 , the controller 4 drives and controls the power motor 7 , thereby positioning the self-propelled robot 1 at a predetermined position in front of the ID panel 21 on the cart 2 .

Next, the ID panel 21 will be described in detail.

Here, FIG. 2 is a perspective view showing an example in which the ID panel 21 is arranged on the cart 2. As shown in FIG. As shown in FIG. 2 , the ID panel 21 is arranged substantially centrally on the front surface of the cage carriage 2 . More specifically, the ID panel 21 is arranged at a position facing the range sensor 9 of the self-propelled robot 1 (see FIG. 1). The ID panel 21 is attachable to and detachable from the cage carriage 2 and is installed at a predetermined position such as the central frame (vertical bar) of the cage carriage 2 by an operator. Since the angle of the ID panel 21 is synonymous with the angle of the cage truck 2 , it is installed so as to be parallel to the front portion of the cage truck 2 .

In order for the self-propelled robot 1 to connect the cage carriage 2, the self-propelled robot 1 needs to detect the distance and angle between the cage carriage 2 and the self-propelled robot 1 and travel toward the cage carriage 2. . However, when the range sensor 9 recognizes the shape of the cage truck 2, the shape to be recognized changes depending on the loading condition of the cage truck 2, so it is difficult to accurately detect the distance and angle to the cage truck 2. . Therefore, in the present embodiment, the ID panel 21 is attached to the cart 2 and the range sensor 9 mounted on the self-propelled robot 1 detects the ID panel 21 .

Here, the ID panel 21, which is an identification member, will be technically described. The ID panel 21 is an identification member for detecting and identifying a detection target by a detection device using electromagnetic waves such as a laser range finder (LRF). In order to perform detection using electromagnetic waves or the like, the detection surface (for example, the surface of the ID panel 21) where the electromagnetic waves are detected is geometrically arranged in at least three directions in the first direction (horizontal direction in the ID panel 21 shown in FIG. 2). It is divided into regions, and in a plurality of divided regions, at least adjacent regions are set to have different reflectances with respect to electromagnetic waves and the like. A detector such as a laser range finder (LRF) also scans in this first direction. In the case of a laser range finder (LRF), the laser scans in this first direction.

Then, the detection device detects and identifies a detection target by detecting a specific pattern (signal) using a difference in intensity of a reflected signal when an electromagnetic wave or the like is irradiated.

The transport system of the present embodiment using the self-propelled robot 1 automates the work of transporting a transport object with casters such as a basket trolley 2 in a distribution warehouse or the like. The transportation operation by the self-propelled robot 1 is divided into the following three operations (1) to (3).
(1) Searching and connecting objects to be transported in the temporary storage area (2) Traveling in the travel area (3) Searching for storage locations and unloading in the storage area

FIG. 3 is an explanatory diagram showing an example of a distribution warehouse 1000 to which the transportation system is assumed. FIG. 3 shows a plan view of the floor surface of the distribution warehouse 1000 viewed from the ceiling side. The XY plane shown in FIG. 3 is a plane parallel to the floor surface, and the Z axis indicates the height direction. In the physical distribution warehouse 1000 shown in FIG. 3, the temporary storage area A1 of (1) above is assumed to be a place where, for example, packages after picking (collection work in the warehouse) or unloaded packages are arranged. The storage area A2 in (3) above is assumed to be an area in front of the truck parking position for each direction of the truck berth, or an area in front of the elevator when transferring to another floor by an elevator or the like. Also, the traveling area A3 in (2) above is assumed to be a place where the arrow in FIG. 3 indicates a round-trip route between the temporary storage area A1 and the storage area A2.

The self-propelled robot 1 moves on the main line by a guidance method based on line recognition in which a sensor recognizes the line of the magnetic tape installed on the floor. Also, the area is determined by detecting the area mark 52 on the side of the line. Further, the ID panel 21 includes information on the storage area A2 to be the transfer destination and information on the order of priority.

As shown in FIG. 3, a magnetic tape for guiding the self-propelled robot 1 is provided in a line in the travel area A3, and a travel line 51 along which the self-propelled robot 1 travels is provided. Also, area marks 52 are arranged near the travel line 51 at the start and end positions of the temporary placement area A1 and the storage area A2 in the travel area A3 to recognize in which area the self-propelled robot 1 is located. It is possible.

In the program executed by the self-propelled robot 1, which will be described later, an action can be specified for each area. The self-propelled robot 1 performs the connection operation of the basket carriage 2 in the temporary storage area A1, and the operation of putting the basket carriage 2 into the garage in the storage area A2. After the transportation of the basket trolley 2 to the storage area A2 is completed, the self-propelled robot 1 automatically moves to the temporary storage area A1 where the basket trolley 2 is placed in order to carry the next basket trolley 2 without the help of an operator. Move by running.

In this embodiment, the travel line 51 made of magnetic tape for guiding the self-propelled robot 1 is provided in the travel area A3, but the present invention is not limited to this. For example, the travel line 51 is not essential in the travel area A3, and area marks may be installed at predetermined intervals. In this case, the self-propelled robot 1 determines its own position from the number of rotations of the drive wheels 71 and the driven wheels 72 and the like, and travels between the area marks.

In the present embodiment, the temporary placement area A1 and the storage area A2 are arranged immediately beside the travel line 51. As shown in FIG. The self-propelled robot 1 searches the areas of the temporary placement area A1 and the storage area A2 while traveling along the travel line 51. - 特許庁When the basket trolley 2 to be transported is found in the temporary placement area A1, the connection operation to the basket trolley 2 from the running line 51 is performed. Also, in the storage area A2, a vacant address is searched from the traveling line 51, and the operation of putting the basket truck 2 into the garage is performed.

In addition, in the distribution warehouse 1000 shown in FIG. 3, a plurality of retroreflective tapes 53, which are reflective materials, are installed on the opposite side of the storage area A2 across the travel line 51 and at a position spaced apart from the storage area A2. ing. A plurality of retroreflective tapes 53 are installed at positions that can be detected by the range sensor 9 of the self-propelled robot 1 . The self-propelled robot 1 estimates its own position based on the installation information of the plurality of retroreflective tapes 53 .

Next, the controller 4 of the self-propelled robot 1 will be explained.

Here, FIG. 4 is a block diagram showing an example of the hardware configuration of the controller 4 of the self-propelled robot 1. As shown in FIG. As shown in FIG. 4, the controller 4 includes a control device 11 such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), and a main storage device 12 such as a ROM (Read Only Memory) or a RAM (Random Access Memory). , an auxiliary storage device 13 such as an SSD (Solid State Drive), a display device 14 such as a display, an input device 15 such as a keyboard, and a communication device 16 such as a wireless communication interface. It has a hardware configuration using a computer.

The control device 11 executes various programs stored in the main storage device 12 and the auxiliary storage device 13 to control the overall operation of the controller 4 (self-propelled robot 1) and realize various functional units described later. .

The program executed by the controller 4 of the self-propelled robot 1 is a file in an installable format or an executable format on a computer such as a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk). It may be configured to be recorded on a readable recording medium and provided.

Furthermore, the program to be executed by the controller 4 of the self-propelled robot 1 may be stored on a computer connected to a network such as the Internet, and provided by being downloaded via the network. Alternatively, the program executed by the controller 4 of the self-propelled robot 1 may be provided or distributed via a network such as the Internet.

Next, the functions that the controller 4 of the self-propelled robot 1 exhibits when the control device 11 of the controller 4 of the self-propelled robot 1 executes the programs stored in the main storage device 12 and the auxiliary storage device 13 will be described. Here, description of conventionally known functions will be omitted, and the characteristic functions exhibited by the controller 4 of the self-propelled robot 1 of the present embodiment will be described in detail.

Part or all of the functions exhibited by the controller 4 of the self-propelled robot 1 may be configured using a dedicated processing circuit such as an IC (Integrated Circuit).

FIG. 5 is a block diagram showing a functional configuration example exhibited by the controller 4 of the self-propelled robot 1. As shown in FIG. As shown in FIG. 5 , the controller 4 of the self-propelled robot 1 includes frequency acquisition means 111 and feedback control means 112 .

The frequency acquisition means 111 acquires a resonance frequency based on the weight of the object to be conveyed (car 2). A specific acquisition method will be described later.

The feedback control means 112 attenuates the resonance frequency range acquired by the frequency acquisition means 111 from a control signal (details will be described later) for controlling the steering angle, and executes steering feedback control.

Next, feedback control (steering control) of steering of the self-propelled robot 1 will be described.

In general, in the self-propelled robot 1, which is a line tracing type automated guided vehicle (AGV: Automated Guided Vehicle), there are wheel diameter errors and assembly errors between the left and right driving wheels, and especially in the case of a differential drive type, Since there are individual differences in the number of revolutions of the motor, the vehicle may turn slightly even when instructed to run straight, so it is necessary to always steer left and right to correct the direction of travel even when going straight. Therefore, the self-propelled robot 1 performs feedback control to correct the direction of travel by constantly steering left and right when tracing and moving on the track.

Correcting the direction of travel by constantly steering left and right means that the self-propelled robot 1 moves by tracing the track while swaying left and right. However, the resonant frequency differs depending on the weight of the load loaded on the object to be conveyed (basket trolley 2). Therefore, the frequencies that increase the left-right sway when tracing and moving on this trajectory are different. In other words, there is a specific frequency (frequency of sway) that increases the sway, depending on the weight of the load loaded on the object to be conveyed (basket carriage 2).

In steering feedback control, the frequency is the reciprocal of the left-right steering cycle (left-right steering speed), and the gain is a coefficient that determines the magnitude of the left-right steering angle.

That is, when the self-propelled robot 1 of the present embodiment tows an object to be conveyed (basket carriage 2), the weight of the object to be conveyed (basket carriage 2) can be reduced by traveling while constantly steering. It is important to prevent this because it will increase the wobble at certain frequencies depending on the frequency.

Here, FIG. 6 is a diagram showing the configuration of the steering control system. As shown in FIG. 6, the steering controller 101 functions as feedback control means 112, and includes a comparator 102, a controller 103, a BEF (Band Elimination Filter) 104, and a steering control section 105. Prepare. Schematically, the steering controller 101 controls the self-propelled robot 1, which is an autonomous mobile device, and when the self-propelled robot 1, which is an autonomous mobile device, runs on a track, it is steered to the left and right to change the traveling direction. fix it. The measuring instrument 5 also includes a camera 106 and a position calculator 107 . The camera 106 senses the position of the trajectory viewed from the self-propelled robot 1 , and the position calculator 107 calculates the position of the self-propelled robot 1 with respect to the trajectory sensed by the camera 106 and inputs it to the steering controller 101 .

In FIG. 6, thin arrows indicate signal flow, and thick arrows indicate that the self-propelled robot 1 is controlled by the steering controller 101 and that the measuring instrument 5 senses the self-propelled robot 1. showing.

The comparator 102 of the steering controller 101 inputs the difference between the position of the self-propelled robot 1 with respect to the trajectory input from the measuring device 5 and the target value (=position error is 0) to the controller 103 as a deviation (=position error). do.

The controller 103 of the steering controller 101 creates a control signal (1) for controlling the steering angle for making the input deviation zero, and outputs it to the BEF 104 .

The BEF 104 is a filter circuit that attenuates only signals of a certain range of frequencies and passes signals of other frequencies, and is also called a band-rejection filter or a band-stop filter.

BEF 104 generates control signal ( 2 ) by attenuating the resonance frequency based on the weight of the object to be conveyed (car carriage 2 ) obtained by frequency obtaining means 111 from control signal ( 1 ), and outputs the control signal ( 2 ) to steering control unit 105 . .

The steering control unit 105 controls the steering angle of the self-propelled robot 1 based on the control signal (2).

In this embodiment, the frequency acquisition means 111 estimates the weight of the cargo loaded on the object to be conveyed (basket cart 2) from the drive current at the start of transportation, and determines a specific frequency that increases the fluctuation (the frequency) is obtained, and in feedback control of the steering, the steering angle of the self-propelled robot 1 is controlled by a control signal obtained by attenuating the frequency of this fluctuation, thereby conveying the object to be conveyed (cart 2). To suppress staggering of a robot 1 when traveling.

Here, FIG. 7 is a diagram showing an example of frequency characteristics of a controlled object.

FIG. 7(a) shows an example of the frequency characteristic of the response to the steering input to the controlled object. In FIG. 7A, both the vertical axis and the horizontal axis are logarithmic. FIG. 7(a) shows the responsiveness for each frequency when control signals for controlling steering with a constant magnitude are applied at various frequencies while the self-propelled robot 1 is traveling at a constant speed.

As shown in FIG. 7A, when the frequency of the control signal is low, the responsiveness of the self-propelled robot 1 is high, the amount of movement of the self-propelled robot 1 in response to steering is relatively large, and the frequency of the control signal is increases, the responsiveness of the self-propelled robot 1 decreases, and the amount of movement of the self-propelled robot 1 in response to steering becomes relatively small.

However, in FIG. 7A, the responsiveness of the self-propelled robot 1 is high around 0.6 to 0.8 Hz. This is because when the control signal for controlling the steering angle of the self-propelled robot 1 contains a frequency in the vicinity of this 0.6 to 0.8 Hz, the self-propelled robot 1 has a high responsiveness. This indicates that the amount of movement corresponding to steering increases, in other words, that the vehicle tends to wobble.

This phenomenon is caused by resonance at a specific frequency depending on the weight of the self-propelled robot 1 and the combined weight of the self-propelled robot 1 and the object to be conveyed (basket carriage 2) when they are connected.

Here, although the weight of the self-propelled robot 1 does not change, the weight of the object to be conveyed (basket carriage) viewed from the self-propelled robot 1 changes depending on the load condition of the object to be conveyed (basket truck 2). In other words, the frequency at which this resonance occurs (resonance frequency), the weight of the object to be conveyed (basket truck) as viewed from the self-propelled robot 1, and the load status of the object to be conveyed (basket truck 2) change.

Since the weight of the object (basket truck 2) viewed from the self-propelled robot 1 changes depending on the load status of the object (basket truck 2), the control signal for controlling the steering angle of the self-propelled robot 1 Although it was difficult to remove this resonance frequency, the frequency range of the BEF 104 in the steering controller 101 for removing this resonance frequency was determined by estimating the weight of the object to be conveyed (cart 2) viewed from the self-propelled robot 1. can be set.

FIG. 7B shows an example of frequency characteristics of the BEF 104. FIG. In FIG. 7B, both the vertical axis and the horizontal axis are logarithmic. The vertical axis of FIG. 7B represents the magnitude of the output control signal (2) (magnitude of the steering angle when steering the self-propelled robot 1) and the magnitude of the input control signal (1). It is divided by (magnitude of the steering angle when steering the self-propelled robot 1), and is called "gain" in control engineering.

For example, as shown in FIG. 7(b), the BEF 104 generates a control signal (2 ) is set as a filter to generate

FIG. 8 is a diagram for explaining control signal (1) and control signal (2), which are control signals for controlling the steering angle. Control signal (1) in FIG. 8 indicates that the vehicle is steered to the target steering angle of 1.0 [rad] in 2.6 seconds. On the other hand, the control signal (2), which is obtained by attenuating the frequency in the vicinity of 0.6 to 0.8 Hz from the control signal (1), is a signal that steers the target steering angle to 1.0 [rad] over 5 seconds. becomes. By attenuating a specific frequency from the control signal in this way, the control time (slope in FIG. 8) until steering to the target steering angle changes.

Next, estimation of the weight of the object to be conveyed (basket truck 2) will be described. Here, FIG. 9 is a diagram showing the relationship between the weight of the object to be conveyed and the current.

The frequency acquisition means 111 estimates the weight of the object to be conveyed (the cart 2) by, for example, the following method. When the motor rotates at a constant speed, the load torque applied to the motor is proportional to the input current, and the weight of the cage truck 2 acts as rolling resistance of the wheels of the cage truck 2 (=the load torque is proportional to the weight of the cage truck 2). to do). First, an object having a known weight is loaded on the cart 2, and the self-propelled robot 1 is caused to travel at a specific motor rotation speed (about 2500 rpm for both left and right). At that time, the input current [A] to the motor driver is measured and plotted against the weight to create the relationship between the weight and the current of the object to be conveyed (basket truck 2) as shown in FIG. Furthermore, the relationship between the weight of the car carriage 2 and the frequency of the fluctuation is similarly grasped by actual measurement when traveling on a straight track or mechanism simulation.

From the above, during actual operation, the self-propelled robot 1 is run for about 1 m at a specific motor rotation speed (about 2500 rpm for both left and right) as described above, and the input current to the motor driver is measured. From the obtained relationship shown in FIG. 9, it is possible to estimate the weight of the object to be conveyed (basket truck 2) and obtain the frequency range set by the BEF 104. FIG.

As described above, according to the present embodiment, it is possible to suppress swaying of the self-propelled robot 1 that conveys the object to be conveyed (basket cart 2) during traveling. In particular, it is possible to suppress an increase in fluctuation at a specific frequency corresponding to the weight of a load loaded on an object to be conveyed while the object is being conveyed.

Furthermore, for example, when traveling in a narrow aisle in a warehouse, the influence of this swaying is great, but by suppressing the swaying, the object to be conveyed (car trolley 2) can be conveyed even in the narrow passage.

In the present embodiment, the self-propelled robot 1, which is an autonomous mobile device to be controlled, is a line trace type that runs on a track. It may be of a guideless (trackless) type that runs on a running track.

(Second embodiment)
Next, a second embodiment will be described.

The transport system of the second embodiment differs from the first embodiment in that the fluctuation frequency immediately after the start of transport is measured. Hereinafter, in the description of the second embodiment, the description of the same portions as those of the first embodiment will be omitted, and the portions different from those of the first embodiment will be described.

In the first embodiment, the weight of the cargo loaded on the object to be conveyed (basket cart 2) is estimated from the drive current at the start of conveyance, and the fluctuation frequency is obtained. In the embodiment, the frequency of fluctuation is obtained by measuring the frequency of fluctuation immediately after the start of transportation.

Here, FIG. 10 is a diagram showing the relationship between the weight of the object to be conveyed and the current for detection of the fluctuation frequency according to the second embodiment.

For example, the self-propelled robot 1 travels at 0.5 m/s in a 10-m straight section with the object to be conveyed (cart 2) connected. In this way, the wobble of the object to be conveyed (basket carriage 2) connected to the self-propelled robot 1 during travel is measured.

In addition, such measurement data can be obtained by providing an angle sensor at the connection between the self-propelled robot 1 and the object to be conveyed (basket carriage 2) and using a range sensor mounted on the self-propelled robot 1. Various methods can be used, such as providing a distance measuring sensor for measuring the distance to the object to be conveyed (basket carriage 2) in the robot 1, or providing a pressure sensor in the bumper portion of the self-propelled robot 1.

The data measured as described above are, for example, as shown in FIG. In the example shown in FIG. 10, the number of peak-to-peak repetitions of the value is counted per 20 seconds. By dividing the measurement time by 20 seconds, the frequency of the sway can be obtained. In the case of FIG. 10, the fluctuation frequency is 0.4 Hz from 8 pieces/20 seconds.

The steering controller 101 sets the frequency range of the BEF 104 shown in FIG. 7(b) from the fluctuation frequency obtained as described above, and can prevent the object to be conveyed (cargo cart 2) from fluctuation.

In addition, the running time for obtaining the fluctuation frequency of the object to be conveyed (basket truck 2) should be within 30 seconds after the object to be conveyed (basket truck 2) is connected to the self-propelled robot 1 and starts running. is desirable. At first it staggers, but after that the stagger is suppressed and you can enter a narrow passage.

As described above, according to the present embodiment, even if the power source is an autonomous mobile device other than an electric motor, the self-propelled robot 1 that transports the object to be transported (basket cart 2) can be prevented from wobbling during travel. In particular, it is possible to suppress an increase in fluctuation at a specific frequency corresponding to the weight of the cargo loaded on the object to be conveyed (the cart 2) when the object is being conveyed.

The fluctuation frequency of the object to be conveyed (basket carriage 2) can also be obtained by causing the self-propelled robot 1 to perform the same operation as the above measurement and obtaining the positional error with respect to the trajectory of the self-propelled robot 1. This is because the wobbling of the object to be conveyed (basket carriage 2) causes torque in the turning direction to be applied to the leading self-propelled robot 1, which appears as a positional error behavior with respect to the trajectory.

In each embodiment, an automated guided vehicle (AGV) that automatically transports the basket trolley 2 to a desired destination by automatically connecting to and towing a towed trolley such as the basket trolley 2 that is a connection target. Although an example in which the self-propelled robot 1 is applied to an autonomous mobile device has been described, it is needless to say that it is not limited to this and can be applied to various autonomous mobile devices.

REFERENCE SIGNS LIST 1 autonomous mobile device 2 object to be conveyed 111 frequency acquisition means 112 feedback control means

Japanese Patent No. 5848915 JP 2018-090084 A

Claims (8)

In an autonomous mobile device that transports an object to be transported,
frequency obtaining means for obtaining a resonance frequency of the object to be conveyed;
For a control signal for controlling steering of the autonomous mobile device, a filter that attenuates a control output in a range including the resonance frequency is used to reduce the gain in the frequency range including the resonance frequency from the control signal to perform steering control. a control means for performing
An autonomous mobile device comprising: the frequency obtaining means obtains the resonance frequency by estimating the weight of the object to be conveyed;
The autonomous mobile device according to claim 1, characterized in that: the frequency obtaining means obtains the resonance frequency based on running behavior;
The autonomous mobile device according to claim 1, characterized in that: the frequency obtaining means obtains the resonance frequency from the fluctuation behavior of the object to be conveyed;
The autonomous mobile device according to claim 3, characterized in that: wherein the frequency acquisition means obtains the resonance frequency from the fluctuation behavior of the autonomous mobile device;
The autonomous mobile device according to claim 3, characterized in that: The frequency acquisition means sets the time for movement to obtain the resonance frequency to be within 30 seconds from the start of movement.
The autonomous mobile device according to any one of claims 3 to 5, characterized in that: The computer that controls the autonomous mobile device that transports the object to be transported,
frequency obtaining means for obtaining a resonance frequency of the object to be conveyed;
For the control signal for controlling the steering of the autonomous mobile device, a filter that attenuates the control output in the range including the resonance frequency is used to reduce the gain in the frequency range including the resonance frequency from the control signal to perform steering control. a control means to implement;
A program to function as A steering method for an autonomous mobile device that conveys an object to be conveyed,
a frequency acquisition step of acquiring a resonance frequency of the object to be conveyed;
For the control signal for controlling the steering of the autonomous mobile device, a filter that attenuates the control output in the range including the resonance frequency is used to reduce the gain in the frequency range including the resonance frequency from the control signal to perform steering control. a control process to be performed;
A steering method for an autonomous mobile device, comprising:

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