Control system for omnidirectional mobile vehicles

Abstract

The present invention aims to provide a control device that enables high-precision stopping of an omnidirectional mobile vehicle driven by a drive motor, regardless of the floor surface conditions, and an omnidirectional mobile vehicle equipped with the control device. [Solution] The control device for an omnidirectional vehicle includes a motor drive command generation unit for measuring floor surface movement characteristics, a floor surface movement characteristics measurement unit, and a floor surface movement characteristics storage unit for measuring floor surface movement characteristics in advance; a movement path execution unit and a motor drive command generation unit for movement path execution for performing path-following driving during normal driving; and a stop position error measurement unit and a motor drive command generation unit for correction movement for performing corrective movement according to the floor surface movement characteristics after path-following driving.

Description

Technical Field

[0001] The present invention relates to a control device for an omnidirectional mobile vehicle.

Background Art

[0002] In recent years, due to the shortage of labor force and the spread of work-style reforms, the need for automation and labor-saving has been increasing at various work sites. In particular, omnidirectional mobile vehicles are applied to the automation of work sites such as factories and warehouses, and are utilized in AGVs (Automatic Guided Vehicles), AMRs (Autonomous Mobile Robots), and mobile collaborative robots. Since omnidirectional mobile vehicles can freely move in any direction on the floor surface, they can efficiently move in narrow spaces and complex routes. However, in order to stop an omnidirectional mobile vehicle accurately at a target position and orientation, there are several technical problems.

[0003] First, there are problems such as the motor having a dead zone with respect to the control input and slip occurring between the mobile vehicle and the floor surface. As a result, it is difficult to perform high-precision control of micro-movements (about several millimeters to several centimeters) by a general feedback control method. Regarding this problem, Patent Document 1 discloses a control method for removing the influence of the dead zone, but it cannot address the problem of slip between the mobile vehicle and the floor surface.

[0004] Second, it has been clarified by the research of the present inventors that the dynamic characteristics of an omnidirectional mobile vehicle change depending on the properties of the floor surface on which it moves. For example, compared to a floor surface with high rigidity such as an iron plate, on a floor surface with low rigidity such as vinyl chloride or rubber, the rolling resistance of the wheels is large, and the actual amount of movement for the same speed command tends to decrease. Therefore, it is effective to change the control parameters of the movement control device for each operating environment of the omnidirectional mobile vehicle.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The present invention was proposed to solve the above-mentioned problems, and its objective is to provide a control device for an omnidirectional mobile vehicle that can stop an omnidirectional mobile vehicle driven by a drive motor with high precision regardless of the floor surface conditions. [Means for solving the problem]

[0007] One aspect of the present invention is, A control device for an omnidirectional vehicle, which is equipped with multiple omnidirectional wheels that can be rotated independently by drive motors, to move the vehicle to a target stopping position, A motor drive command generation unit for floor surface movement characteristics measurement generates a drive command for the drive motor in order to perform a movement characteristic measurement run for measuring the movement characteristics of the omnidirectional vehicle, A floor surface movement characteristic measuring unit measures the movement characteristics of the omnidirectional vehicle by the aforementioned movement characteristic measuring run, A floor movement characteristic storage unit stores the movement characteristics of the omnidirectional mobile vehicle measured by the floor movement characteristic measurement unit, When performing normal driving, the movement path execution unit determines the movement path to reach the target stopping position of the omnidirectional vehicle, A movement path execution motor drive command generation unit generates a drive command for the drive motor to move the omnidirectional mobile vehicle along the movement path determined by the movement path execution unit, A stopping position error measuring unit that measures the error between the target stopping position and the actual stopping position of the omnidirectional vehicle, The system includes a correction movement motor drive command generation unit that generates drive commands for each wheel of the omnidirectional mobile vehicle to perform movement that corrects the error in the stopping position, based on the error in the stopping position measured by the stopping position error measurement unit and the movement characteristics stored in the floor surface movement characteristics storage unit. Here, the movement characteristics refer to a mathematical model that expresses the relationship between the drive command that rotates the drive motor of the omnidirectional vehicle and the actual amount of movement using mathematical formulas or tables.

[0008] The drive motor that drives omnidirectional wheels has a dead zone in response to control input. Furthermore, slippage occurs between the omnidirectional wheels and the floor surface while the omnidirectional vehicle is in motion. Therefore, it is difficult to precisely rotate a stationary drive motor by a small amount. Moreover, these phenomena vary depending on the properties of the floor surface on which the omnidirectional vehicle travels.

[0009] However, the movement characteristics of the omnidirectional vehicle, which originate from the dead zone and slippage, are reproducible on the same floor surface. Therefore, by measuring and storing the movement characteristics in advance and appropriately determining the motor drive command according to the stored movement characteristics, it becomes possible to drive the omnidirectional vehicle to the target stopping position with high precision. The present invention is based on such findings. [Effects of the Invention]

[0010] According to the present invention, the stopping accuracy of an omnidirectional mobile vehicle relative to a target position and orientation can be improved without being affected by the floor surface properties of the site environment in which the omnidirectional mobile vehicle is used. Further features related to the present invention will become apparent from the description herein and the accompanying drawings. In addition, problems, configurations, and effects other than those described above will become apparent from the following description of embodiments. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing the configuration of a control device for an omnidirectional vehicle according to Embodiment 1 of the present invention. [Figure 2] This is a plan view of an omnidirectional mobile vehicle 2 controlled by a control device for an omnidirectional mobile vehicle according to Embodiment 1 of the present invention. [Figure 3] This figure illustrates the situation when measuring the stopping position error of an omnidirectional mobile vehicle according to Embodiment 1 of the present invention at a work site. [Figure 4]It is a flowchart showing the order in which the control device 1 of the omnidirectional moving vehicle according to Example 1 of the present invention exhibits its functions. [Figure 5] It is a flowchart showing the method by which the control device 1 of the omnidirectional moving vehicle according to Example 1 of the present invention realizes the floor surface movement characteristic measurement function. [Figure 6] It is a flowchart showing the method by which the control device 1 of the omnidirectional moving vehicle according to Example 1 of the present invention realizes the path following movement function. [Figure 7] It is a flowchart showing the method by which the control device 1 of the omnidirectional moving vehicle according to Example 1 of the present invention realizes the correction movement function. [Figure 8] It is a block diagram showing the configuration of the control device 1 of the omnidirectional moving vehicle according to Example 2 of the present invention. [Figure 9] It is a flowchart showing the method by which the control device 1 of the omnidirectional moving vehicle according to Example 2 of the present invention realizes the floor surface movement characteristic measurement function. [Figure 10] It is a block diagram showing the configuration of the control device 1 of the omnidirectional moving vehicle according to Example 3 of the present invention. [Figure 11] It is a block diagram showing the configuration of the control device 1 of the omnidirectional moving vehicle according to Example 4 of the present invention. [Figure 12] It is a diagram for showing how the stop accuracy monitoring unit of the control device 1 of the omnidirectional moving vehicle according to Example 4 of the present invention prompts the user to re - perform the floor surface movement characteristic measurement. [Figure 13] It is a block diagram showing the configuration of the control device 1 of the omnidirectional moving vehicle according to Example 5 of the present invention. [Figure 14] [[ID=~]]It is a flowchart showing the method by which the control device 1 of the omnidirectional moving vehicle according to Example 5 of the present invention realizes the floor surface movement characteristic measurement function. [Figure 15] It is a scatter diagram for explaining the method by which the reliability calculation unit of the control device 1 of the omnidirectional moving vehicle according to Example 5 of the present invention derives the reliability. [Figure 16] It is a diagram for showing the situation where the floor surface movement characteristic measurement progress display unit of the control device 1 of the omnidirectional moving vehicle according to Example 6 of the present invention displays the progress of the floor surface movement characteristic measurement. [Figure 17]It is a diagram showing a situation where an estimated maximum stop position error display unit of a control device 1 of an omnidirectional moving vehicle according to Example 6 of the present invention displays an estimated maximum stop position error. [Figure 18] It is a block diagram showing a configuration of a computer 1000 that realizes the control device 1.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments are merely examples for explaining the present invention and do not limit the present invention. For the sake of clarity of explanation, appropriate omissions and simplifications are made. The present invention can also be implemented with various other examples or examples in which some or all of the examples are combined. Unless otherwise particularly limited, each component may be singular or plural. Also, in the description of the embodiments described later, the description will focus on the differences from the already described embodiments, and the description of the overlapping parts will be omitted as appropriate.

[0013] [Example 1] FIG. 1 is a block diagram showing a schematic configuration of a control device of an omnidirectional moving vehicle according to Example 1 of the present invention, and FIG. 2 is a plan view of an omnidirectional moving vehicle 2 controlled by the control device of the omnidirectional moving vehicle according to Example 1 of the present invention. In FIG. 1, the control device 1 of the present embodiment is connected to an omnidirectional moving vehicle 2 and an external sensor 3. In FIG. 1, the control device 1 of the present embodiment is mounted on an omnidirectional moving vehicle 2 as shown in FIG. 2. The omnidirectional moving vehicle 2 is a vehicle that can move in three directions: the front-rear direction (x-axis direction in FIG. 2), the left-right direction (y-axis direction in FIG. 2), and the turning direction (θ direction in FIG. 2), and can move freely on the floor surface.

[0014] The omnidirectional moving vehicle includes a plurality of omnidirectional moving wheels that can be independently rotated by a drive motor. Examples of the omnidirectional moving vehicle 2 include the four-wheel mecanum wheel system shown in FIG. 2(a), the four-wheel omni wheel system shown in FIG. 2(b), and the three-wheel omni wheel system shown in FIG. 2(c). FIG. 1 shows a configuration example for the four-wheel mecanum wheel system, and hereinafter, the embodiments will be described taking the four-wheel mecanum wheel system as an example.

[0015] The omnidirectional vehicle 2 has independently driven omnidirectional wheels 23A to 23D, each driven by a drive motor 22A to 22D. The drive motors 22A to 22D are controlled by a drive motor control unit 21. The drive motors 22A to 22D are, for example, speed-controllable three-phase motors or brushless motors. Alternatively, the drive motors 22A to 22D may be position-controllable servo motors.

[0016] Figure 3 is a diagram illustrating the situation when an omnidirectional mobile vehicle according to Embodiment 1 of the present invention measures the stopping position error at a work site. The external sensor 3 is, for example, a monocular camera, and as shown in Figure 3, it images a position measurement marker 5 having a specific pattern that is installed on the surrounding structure 4. The external sensor 3 may also be a binocular camera. Alternatively, the external sensor 3 may be a LiDAR (Light Detection And Ranging) or a depth camera capable of acquiring depth images, in which case the position measurement marker 5 is a three-dimensional object having a specific shape. The external sensor 3 may also be a binocular infrared camera, in which case the position measurement marker 5 is a predetermined structure that strongly reflects infrared light.

[0017] The control device 1 is a computer composed of a processor, memory, storage, network interface, etc. The control device 1 receives sensor data acquired by the external sensor 3, processes the information, and then controls the drive motors 22A to 22D by outputting motor drive commands to the drive motor control unit 21.

[0018] Figure 4 is a flowchart showing the sequence in which the control device 1 of the omnidirectional vehicle activates its functions. First, in the preparation phase, the control device 1 measures the floor surface movement characteristics (S11). Then, in the normal driving phase, the control device 1 performs path-following movement (S12) followed by correction movement (S13) to achieve highly accurate stopping relative to the target stopping position.

[0019] Returning to Figure 1, the control device 1 has a motor drive command generation unit 11 for floor surface movement characteristic measurement (S11), a floor surface movement characteristic measurement unit 12, a floor surface movement characteristic storage unit 13, a movement path execution unit 14, a motor drive command generation unit 15 for movement path execution, a stop position error measurement unit 16, and a motor drive command generation unit 17 for correction movement, in order to realize the three functions described above: floor surface movement characteristic measurement (S11), path following movement (S12), and correction movement (S13).

[0020] The floor surface movement characteristic measurement motor drive command generation unit 11 generates drive commands for measuring the movement characteristics of the omnidirectional vehicle 2, which are expressed as the relationship between the drive command to rotate the drive motor of the omnidirectional vehicle 2 and the actual amount of movement. The floor surface movement characteristic measurement unit 12 measures the movement characteristics of the omnidirectional vehicle. The floor surface movement characteristic storage unit 13 stores the movement characteristics of the omnidirectional vehicle 2 measured by the floor surface movement characteristic measurement unit 12. The movement path execution unit 14 determines the movement path of the omnidirectional vehicle 2 to reach the target stopping position.

[0021] The motor drive command generation unit 15 for movement path execution generates drive commands for the drive motors to move the omnidirectional vehicle 2 along the movement path determined by the movement path execution unit 14. The stop position error measurement unit 16 measures the error between the target stop position of the omnidirectional vehicle 2 and the actual stop position. The motor drive command generation unit 17 for correction movement generates drive commands for each wheel to perform movement that corrects the error in the stop position, based on the error in the stop position measured by the stop position error measurement unit 16 and the movement characteristics stored in the floor surface movement characteristics storage unit 13.

[0022] Figure 5 is a flowchart showing the process by which the control device 1 of the omnidirectional vehicle performs floor surface movement characteristic measurement (S11 in Figure 4). First, the floor surface movement characteristic measurement unit 12 processes the sensor information acquired by the external sensor 3 to obtain the position of the omnidirectional moving vehicle 2 (S21). Next, the floor surface movement characteristic measurement motor drive command generation unit 11 generates a motor drive command to move the omnidirectional moving vehicle 2 (S22). After the movement is completed, the floor surface movement characteristic measurement unit 12 processes the sensor information acquired by the external sensor 3 to obtain the position of the omnidirectional moving vehicle 2 (S23). Then, it calculates the amount of change in the position of the omnidirectional moving vehicle 2 acquired in S21 and S23 (S24), and adds the motor drive command generated in S22 and the amount of change in position calculated in S24 to the memory buffer (S25).

[0023] To return the omnidirectional vehicle 2 to its initial position, the floor surface movement characteristic measurement motor drive command generation unit 11 generates a motor drive command and moves the omnidirectional vehicle 2 to the starting position for floor surface movement characteristic measurement (S26). The system then determines whether the termination conditions for floor surface movement characteristic measurement are met. If the termination conditions are not met, the system returns to S21; if the termination conditions are met, the system proceeds to the next operation (S27).

[0024] In S25, the relationship between the motor drive command stored in the memory buffer and the amount of position change is identified by multiple regression analysis or the like (S28), and the relationship between the motor drive command and the amount of position change identified in S28 is stored in the floor surface movement characteristic storage unit 13 (S29). The relationship between the motor drive command and the amount of position change identified in S28 is the movement characteristic of the floor surface on which this measurement was performed, and is referred to as floor surface movement characteristic measurement.

[0025] Figure 6 is a flowchart showing how the control device 1 of an omnidirectional vehicle according to Embodiment 1 of the present invention realizes a path-following movement function. Figure 6 shows the process by which the control device 1 executes the movement path (S12 in Figure 4).

[0026] First, the movement path execution unit 14 determines the movement path to the target stopping position (S31). The movement path execution motor drive command generation unit 15 generates motor drive commands to move the omnidirectional vehicle along the movement path, causing the omnidirectional vehicle 2 to follow the path (S32). If the distance between the target stopping position and the omnidirectional vehicle 2 is less than a threshold (S33), the movement is terminated (S34); otherwise, the process returns to S31.

[0027] Figure 7 is a flowchart showing how the control device 1 of an omnidirectional vehicle according to Embodiment 1 of the present invention realizes the corrective movement function. Figure 7 shows the process by which the control device 1 performs corrective movement (S13 in Figure 4).

[0028] The stopping position error measurement unit 16 receives information on the target stopping position from the movement path execution unit 14 (S41). The stopping position error measurement unit 16 acquires sensor information from the external sensor 3 and derives the stopping position error of the omnidirectional moving vehicle 2 (S42). The motor drive command generation unit 17 acquires the stopping position error from the stopping position error measurement unit 16 (S43). The motor drive command generation unit 17 acquires the floor surface movement characteristics from the floor surface movement characteristics storage unit 13 (S44). The motor drive command generation unit 17 generates drive commands for each wheel to perform movement that corrects the stopping position error, based on the stopping position error measured by the stopping position error measurement unit 16 and the movement characteristics stored in the floor surface movement characteristics storage unit 13. The corrective movement motor drive command generation unit 17 generates a motor drive command for each wheel that is inferred to minimize the stopping position error based on the floor surface movement characteristics (S45), and outputs the corrective movement motor drive command to the drive motor control unit 21 of the omnidirectional vehicle 2, causing the omnidirectional vehicle 2 to move and stop (S46).

[0029] [Example 2] Figure 8 is a block diagram showing the configuration of the control device 1 for an omnidirectional mobile vehicle according to Embodiment 2 of the present invention, and Figure 9 is a flowchart showing how the control device 1 for an omnidirectional mobile vehicle according to Embodiment 2 of the present invention realizes the floor surface movement characteristic measurement function.

[0030] In the control device 1, improving the stopping accuracy of the omnidirectional vehicle 2 requires improving the accuracy of identifying the floor surface movement characteristics. An omnidirectional vehicle with omnidirectional wheels, as illustrated in Figure 2, generally exhibits different mechanical characteristics depending on the direction of movement, such as the longitudinal, lateral, and turning directions. This is because omnidirectional wheels, such as Mecanum wheels and omniwheels, have a structure in which small rollers are arranged around the surface of the wheel, and the position and number of rotating rollers change depending on the direction of travel of the omnidirectional vehicle. This embodiment discloses a method for measuring floor surface movement characteristics that was discovered in consideration of the characteristics of such an omnidirectional vehicle.

[0031] In this embodiment, the control device 1, in addition to the components described in Embodiment 1, includes a motor command storage unit 111 for measuring the longitudinal direction, a motor command storage unit 112 for measuring the lateral direction, and a motor command storage unit 113 for measuring the rotational direction. The motor command storage unit 111 for measuring the longitudinal direction stores speed commands to the drive motor for measuring the movement characteristics related to movement in the longitudinal direction. The motor command storage unit 112 for measuring the lateral direction stores speed commands to the drive motor for measuring the movement characteristics related to movement in the lateral direction. The motor command storage unit 113 for measuring the rotational direction stores speed commands to the drive motor for measuring the movement characteristics related to movement in the rotational direction. The motor drive command generation unit 11 for measuring floor surface movement characteristics outputs the motor commands stored in the motor command storage unit 111 for measuring the longitudinal direction, the motor command storage unit 112 for measuring the lateral direction, and the motor command storage unit 113 individually.

[0032] Figure 9 shows the process by which the control device 1 in Embodiment 2 performs floor surface movement characteristic measurement. Steps S21, S23, S24, S25, S26, S27, S28, and S29 are the same as in Figure 5, but the form in which the motor drive command generation unit 11 for floor surface movement characteristic measurement generates motor drive commands is more concrete.

[0033] After the floor surface movement characteristic measurement unit 12 processes the sensor information acquired by the external sensor 3 and obtains the position of the omnidirectional moving vehicle 2 (S21), the floor surface movement characteristic measurement motor drive command generation unit 11 individually determines whether the collection of measurement data in the front-rear direction, left-right direction, and turning direction has been completed (S22a, S22b, S22c).

[0034] Then, for directions where data collection is not yet complete (S22d, S22e, S22f), the motor drive command generation unit 11 for floor movement characteristic measurement acquires motor command values ​​for measuring movement characteristics that have been previously stored in the motor command storage unit 111 for longitudinal direction measurement, the motor command storage unit 112 for lateral direction measurement, or the motor command storage unit 113 for turning direction measurement, and moves the omnidirectional vehicle 2. In other words, the motor drive command generation unit 11 for floor movement characteristic measurement outputs motor commands stored in the motor command storage unit 111 for longitudinal direction measurement, the motor command storage unit 112 for lateral direction measurement, and the motor command storage unit 113 for turning direction measurement individually. The characteristic of this method is that floor movement characteristic measurement is identified independently for each of the longitudinal, lateral, and turning directions. This makes it possible to control the omnidirectional vehicle 2, which has different mechanical characteristics depending on the direction of movement, with high precision.

[0035] [Example 3] Figure 10 is a block diagram showing the configuration of the control device 1 for an omnidirectional vehicle according to Embodiment 3 of the present invention.

[0036] The area in which the omnidirectional vehicle 2 travels may contain multiple regions with different floor surface properties. In such situations, if corrective movement is performed assuming a single floor surface movement characteristic, a large stopping error will occur due to the discrepancy between the floor surface movement characteristic acquired from the floor surface movement characteristic storage unit 13 by the corrective movement motor drive command generation unit 17 to generate motor commands and the actual floor surface movement characteristic. This embodiment aims to prevent such problems.

[0037] Figure 10 shows the configuration of the control device 1 in Embodiment 3. The control device 1 in this embodiment includes, in addition to the components described in Embodiment 1, a position estimation sensor 6 and a position estimation unit 18. The position estimation sensor 6 is, for example, a LiDAR sensor. The position estimation unit 18 processes the sensor information obtained from the position estimation sensor 6 to estimate and output the current position of the omnidirectional mobile vehicle 2.

[0038] In this embodiment, the floor surface movement characteristic storage unit 13 stores the floor surface movement characteristics in association with the position of the omnidirectional moving vehicle 2 at the time the floor surface movement characteristics were measured. When the control device 1 performs a corrective movement, the corrective movement motor drive command generation unit 17 generates a motor drive command for the corrective movement using the floor surface movement characteristics measured at the position closest to the target stopping position among the floor surface movement characteristics stored in the floor surface movement characteristic storage unit 13. As a result, even if the floor surface conditions differ at the target stopping position, corrective movement based on accurate floor surface movement characteristics for each target stopping position can be performed in advance, improving stopping accuracy.

[0039] [Example 4] Figure 11 is a block diagram showing the configuration of the control device 1 for an omnidirectional vehicle according to Embodiment 4 of the present invention, and Figure 12 is a diagram showing how the stopping accuracy monitoring unit of the control device 1 for an omnidirectional vehicle according to Embodiment 4 of the present invention prompts the user to repeat the floor surface movement characteristic measurement.

[0040] Figure 11 shows the configuration of the control device 1 in Embodiment 4. In this embodiment, the control device 1 has a stop accuracy monitoring unit 19 in addition to the components described in Embodiment 1.

[0041] Floor movement characteristics change due to dirt and deterioration of the floor surface, or due to the aging of the omnidirectional vehicle 2 itself. Immediately after measuring the floor movement characteristics, highly accurate stopping relative to the target stopping position can be achieved, but after a long period of time, the same stopping accuracy may not be maintained. This embodiment aims to address this problem.

[0042] In this embodiment, we note that the omnidirectional vehicle 2 can measure the stopping error after correction movement by the stopping position error measurement unit 16 after normal movement, and is characterized by being equipped with a stopping accuracy monitoring unit 19 as shown in Figure 11. The stopping accuracy monitoring unit 19 acquires the stopping position error output by the stopping position error measurement unit 16 after correction movement, compares the stopping position error with a predetermined threshold, and if the stopping position error is greater than the threshold, notifies the system to measure the floor surface movement characteristics at that position.

[0043] Figure 12 schematically shows how the stopping accuracy monitoring unit 19 detects a deterioration in stopping accuracy and notifies the user that remeasurement of the floor movement characteristics is necessary. In this embodiment, the control device 1 communicates information with the tablet terminal 7 held by the user using wireless communication means (not shown). The stopping accuracy deterioration display unit 120 of the tablet terminal 7 can then display a message indicating that the stopping accuracy of the omnidirectional vehicle 2 relative to the target stopping position has deteriorated and prompting the user to remeasure the floor movement characteristics.

[0044] [Example 5] Figure 13 is a block diagram showing the configuration of the control device 1 of the omnidirectional mobile vehicle according to Embodiment 5 of the present invention, Figure 14 is a flowchart showing how the control device 1 of the omnidirectional mobile vehicle according to Embodiment 5 of the present invention realizes the floor surface movement characteristic measurement function, and Figure 15 is a scatter plot illustrating how the reliability calculation unit 121 of the omnidirectional mobile vehicle according to Embodiment 5 of the present invention derives the reliability.

[0045] The control device 1 in this embodiment includes a reliability calculation unit 121 in addition to the components described in Embodiment 1. Measuring floor surface movement characteristics by the control device 1 requires multiple movements to identify the relationship between the motor drive command and the amount of position change, which is time-consuming. This embodiment shows a configuration to shorten the time required for floor surface movement characteristic measurement. This embodiment is characterized by including a reliability calculation unit 121 shown in Figure 13 so that the relationship between the motor drive command and the amount of position change can be identified based on the minimum necessary measurement data.

[0046] The reliability calculation unit 121 calculates the reliability of the floor surface movement characteristics measured by the floor surface movement characteristics measurement unit 12. The floor surface movement characteristics measurement unit 12 continues measuring the floor surface movement characteristics until the reliability calculated by the reliability calculation unit 121 exceeds a threshold.

[0047] Figure 14 shows the method for measuring floor surface movement characteristics in this embodiment. The steps S21-S26, S28, and S29 are the same as in Figure 5, but the distinguishing feature is that the comparison result between the reliability calculated by the reliability calculation unit and the threshold is used as the condition for terminating the run for measuring floor surface movement characteristics (S27'). This is a function in which the reliability increases as the number of measurement data increases. The confidence level is, for example, the width of the confidence interval in the regression analysis shown in Figure 15.

[0048] Figure 15 shows a graph plotting the relationship between the motor drive command and the change in position. Here, the motor drive command is, for example, the integral of the speed command value of the brushless motor that drives the omnidirectional vehicle 2 traveling in the forward and backward directions. If linearity is confirmed between the motor drive command and the change in position, an approximate straight line L1 can be obtained by the least squares method. Also, for example, by calculating the 95% confidence interval for the obtained data, the upper limit L2 and lower limit L2' of the confidence interval can be plotted. If C is the maximum difference between L2 or L2' and L1 among the measured data, then C decreases as the number of data points increases.

[0049] Therefore, the reciprocal of C can be used as an indicator of reliability. By terminating the measurement of floor movement characteristics when the reciprocal of C exceeds a predetermined value, that is, when the reliability exceeds a preset threshold, it is possible to shorten the time required to measure floor movement characteristics while maintaining high stopping accuracy for omnidirectional vehicles.

[0050] [Example 6] Figure 16 is a diagram showing the situation in which the floor surface movement characteristic measurement progress display unit of the control device 1 of the omnidirectional mobile vehicle according to Embodiment 6 of the present invention displays the progress of floor surface movement characteristic measurement.

[0051] The floor movement characteristic measurement by the control device 1 requires multiple movements to identify the relationship between the motor drive command and the amount of position change, so the user needs to wait for the floor movement characteristic measurement to be completed. In this case, if the user does not know the progress of the floor movement characteristic measurement, it becomes difficult to plan work related to the floor movement characteristic measurement. To prevent this problem, this embodiment is characterized by having a floor movement characteristic measurement progress display unit 122 that displays the time remaining until the measurement is completed or the degree of progress, while the floor movement characteristic measurement unit 12 is measuring the floor movement characteristics, as shown in Figure 16.

[0052] In this embodiment, the control device 1 communicates information with the user's tablet terminal 7 using wireless communication means (not shown). The floor surface movement characteristic measurement progress display unit 122 of the tablet terminal 7 displays the time remaining until the measurement is completed or the degree of progress.

[0053] Figure 17 is a diagram illustrating the situation in which the estimated maximum stopping position error display unit of the control device 1 for an omnidirectional mobile vehicle according to Embodiment 6 of the present invention displays the estimated maximum stopping position error. If the user can find out what level of stopping accuracy can be achieved on the target floor surface by measuring the floor surface movement characteristics using the control device 1, the user can easily design the work to be performed by the omnidirectional mobile vehicle 2 using that stopping accuracy as a guideline. In this embodiment, taking such needs into consideration, as shown in Figure 17, the system is characterized by having an estimated maximum stopping position error display unit 123 that displays the maximum stopping position error estimated from the measurement results after measuring the floor surface movement characteristics.

[0054] As shown in Figure 15, one method for calculating the estimated maximum stopping position error is to multiply the standard deviation of the actual measurement result by a predetermined safety factor, which is the approximation line L1 of the data obtained during floor surface movement characteristic measurement. In this embodiment, the control device 1 communicates information with the tablet terminal 7 held by the user using wireless communication means (not shown). The estimated maximum stopping position error is then displayed on the estimated maximum stopping position error display unit 123 of the tablet terminal 7.

[0055] [Configuration of the computer 1000 that implements the control device 1] Figure 18 shows an example configuration of the computer 1000 that implements the control device 1. In computer 1000, the processor 1001, memory such as RAM (Random Access Memory) 1002, storage such as SSD (Solid State Drive) and HDD (Hard Disk Drive) 1003, and network interface 1004 are connected via a bus.

[0056] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add a configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0057] 1: Control device, 2: Omnidirectional vehicle, 3: External sensor, 4: Surrounding structure, 5: Position measurement marker, 6: Position estimation sensor, 11: Motor drive command generation unit for floor surface movement characteristic measurement, 12: Floor surface movement characteristic measurement unit, 13: Floor surface movement characteristic storage unit, 14: Movement path execution unit, 15: Motor drive command generation unit for movement path execution, 16: Stop position error measurement unit, 17: Motor drive command generation unit for correction movement, 18: Position estimation unit, 19: Stop accuracy monitoring unit, 21: Drive motor control unit, 22A~22D: Drive motor, 23A~23D: Omnidirectional wheel, 111: Motor command storage unit for forward / backward direction measurement, 112: Motor command storage unit for left / right direction measurement, 113: Motor command storage unit for turning direction measurement, 121: Reliability calculation unit, 122: Floor surface movement characteristic measurement progress display unit

Claims

1. A control device for an omnidirectional vehicle that moves the omnidirectional vehicle to a target stopping position, A motor drive command generation unit for measuring floor surface movement characteristics generates a drive command for measuring the movement characteristics of the omnidirectional vehicle, which is expressed as the relationship between the drive command for rotating the drive motor of the omnidirectional vehicle and the actual amount of movement. A floor surface movement characteristic measuring unit for measuring the movement characteristics of the omnidirectional vehicle, A floor movement characteristic storage unit stores the movement characteristics of the omnidirectional mobile vehicle measured by the floor movement characteristic measurement unit, A movement path execution unit that determines the movement path to the target stopping position of the omnidirectional vehicle, A movement path execution motor drive command generation unit generates a drive command for the drive motor to move the omnidirectional mobile vehicle along the movement path determined by the movement path execution unit, A stopping position error measuring unit that measures the error between the target stopping position and the actual stopping position of the omnidirectional vehicle, A correction movement motor drive command generation unit generates a drive command for each wheel of the omnidirectional mobile vehicle to perform movement that corrects the error in the stopping position, based on the error in the stopping position measured by the stopping position error measurement unit and the movement characteristics stored in the floor surface movement characteristics storage unit. A control device for an omnidirectional vehicle, characterized by being equipped with the following features.

2. A motor command storage unit for measuring the forward and backward movement, which stores speed commands to the drive motor for measuring the movement characteristics related to movement in the forward and backward direction, A motor command storage unit for measuring left-right movement stores speed commands to the drive motor for measuring movement characteristics related to left-right movement, A motor command storage unit for measuring the turning direction stores speed commands to the drive motor for measuring the movement characteristics related to movement in the turning direction, It has, The control device for an omnidirectional mobile vehicle according to claim 1, characterized in that the motor drive command generation unit for measuring floor surface movement characteristics outputs motor commands stored in the motor command storage unit for measuring the front-rear direction, the motor command storage unit for measuring the left-right direction, and the motor command storage unit for measuring the turning direction individually.

3. It has a position estimation unit that estimates the current position of the omnidirectional vehicle, The floor surface movement characteristic storage unit stores the floor surface movement characteristics in relation to the position of the omnidirectional moving vehicle at the time the floor surface movement characteristics were measured. The control device for an omnidirectional vehicle according to claim 1, characterized in that the motor drive command generation unit for corrective movement generates a motor drive command for corrective movement using the floor surface movement characteristics measured at the position closest to the target stop position.

4. The control device for an omnidirectional vehicle according to claim 1, further comprising a stopping accuracy monitoring unit that acquires the stopping position error output by the stopping position error measurement unit after correction movement, compares the stopping position error with a predetermined threshold, and notifies the user to measure the floor surface movement characteristics at that position if the stopping position error is greater than the threshold.

5. The floor surface movement characteristic measurement unit has a reliability calculation unit that calculates the reliability of the floor surface movement characteristics measured by the floor surface movement characteristic measurement unit, The control device for an omnidirectional vehicle according to claim 1, characterized in that the floor surface movement characteristic measurement unit terminates the measurement of floor surface movement characteristics when the reliability calculated by the reliability calculation unit exceeds a threshold.

6. A control device for an omnidirectional mobile vehicle according to claim 1, further comprising a floor movement characteristic measurement progress display unit that displays the time remaining until the measurement is completed or the degree of progress while the floor movement characteristic measurement unit is measuring the floor movement characteristics.

7. A control device for an omnidirectional vehicle according to claim 1, comprising an estimated maximum stopping position error display unit that displays the maximum stopping position error estimated from the measurement results after measuring the floor surface movement characteristics.

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