Weight measurement system, information processing device, and weight measurement method

Abstract

This technology enables highly accurate weight measurement while moving the object being measured in three dimensions using force sensors, and realizes a versatile weight measurement technology applicable to objects of various weights. [Solution] The weight measurement system (1) comprises a force sensor (20) that can be attached to the gripping part of a transport arm that grips and transports an item, a first acquisition unit (1111) that acquires an output signal from the force sensor when the gripping part moves three-dimensionally while gripping an item, a weight derivation unit (112) that processes the output signal to derive weight data representing the weight of the item, and an output unit (113) that outputs the weight data to the outside.

Description

Technical Field

[0001] The present invention relates to a weight measurement system, an information processing device, and a weight measurement method.

Background Art

[0002] A method of measuring force or weight using a force sensor is known. For example, Patent Document 1 describes a force sensor device including a force sensor, a load cell using the force sensor device, a robot hand, and the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, it is common to measure the weight in a state where the measurement object is stationary. Although there is also a method of measuring the weight while moving the measurement object in the gravitational direction or the horizontal direction in some cases, it is not practical due to operation restrictions, and the necessary measurement accuracy may not always be obtained. In addition, the measurement method using a force sensor is generally limited to a specific measurement object, and there is a problem of lack of versatility.

[0005] One aspect of the present invention aims to realize a general-purpose weight measurement technology that can accurately measure the weight while moving the measurement object three-dimensionally using a force sensor and is applicable to measurement objects of various weights.

Means for Solving the Problems

[0006] To solve the above problems, a weight measuring system according to one aspect of the present invention includes: a force sensor that can be attached to the gripping part of a transport arm that grips and transports an article; a first acquisition unit that acquires an output signal from the force sensor when the gripping part moves three-dimensionally while gripping the article; a weight derivation unit that processes the output signal to derive weight data representing the weight of the article; and an output unit that outputs the weight data to the outside.

[0007] An information processing device according to one aspect of the present invention includes: a first acquisition unit that acquires an output signal from a force sensor attached to a gripping unit of a transport arm that grips and transports an article when the gripping unit moves three-dimensionally while gripping the article; a weight derivation unit that processes the output signal to derive weight data representing the weight of the article; and an output unit that outputs the weight data to the outside.

[0008] A weight measurement method according to one aspect of the present invention includes a first acquisition step of acquiring an output signal from a force sensor attached to a gripping part of a transport arm that grips and transports an article when the gripping part moves three-dimensionally while gripping the article; a weight derivation step of processing the output signal to derive weight data representing the weight of the article; and an output step of outputting the weight data to the outside.

[0009] The control unit of the information processing device according to each aspect of the present invention may be implemented by a computer. In this case, the control program for the information processing device, which enables the computer to implement the information processing device by operating the computer as each part (software element) of the control unit, and the computer-readable recording medium on which the program is recorded, also fall within the scope of the present invention. [Effects of the Invention]

[0010] According to one aspect of the present invention, it is possible to realize a versatile weight measurement technology that can accurately measure the weight of an object to be measured while moving it in three dimensions using a force sensor, and that can be applied to objects of various weights. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing the configuration of the weight measuring system 1 according to Embodiment 1 of the present invention. [Figure 2] This is a schematic diagram showing an example of a transport arm according to Embodiment 1. [Figure 3] This is an example of a schematic plan view from above of a site where a transport arm according to Embodiment 1 is transporting an item. [Figure 4] This is a flowchart showing the flow of the weight measurement method S1 according to Embodiment 1. [Figure 5] This is a block diagram showing the configuration of the weight measurement system 1A according to Embodiment 2. [Figure 6] This flowchart shows the flow of the weight measurement method S2 according to Embodiment 2. [Modes for carrying out the invention]

[0012] [Embodiment 1] One embodiment of the present invention will be described in detail below. Figure 1 is a block diagram showing the configuration of the weight measurement system 1 according to this embodiment 1. The weight measurement system 1 according to this embodiment is a system that can measure the weight of an article grasped by an arbitrary transport arm by being combined with that transport arm. As shown in the figure, the weight measurement system 1 comprises an information processing device 10 and a force sensor 20 that can be attached to the transport arm 50. The information processing device 10 comprises a control unit 11, an input / output IF (interface) 12, at least one processor 13 and at least one memory 14. The information processing device 10 is a device that acquires and processes the output signal from the force sensor 20 and the acceleration data of the transport arm 50, and outputs weight data of the article grasped by the transport arm 50.

[0013] The force sensor 20 is attached to the transport arm 50. The transport arm 50 is a robotic arm or similar mechanical device capable of gripping and moving an object. In the example shown in Figure 1, the transport arm 50 is not included in the weight measurement system 1, but the transport arm 50 may be included in the weight measurement system 1. The force sensor 20 may communicate with the information processing device 10 using the serial communication standard RS-422.

[0014] Figure 2 is a schematic diagram showing an example of a transport arm 50. In Figure 2, a plurality of arm sections 51 connected by a rotation axis indicated by a dashed line and force sensors 20 attached to the ends of the arm sections 51 are shown. Although the gripping section (hand section) for gripping the article is not shown in Figure 2, it is usually attached to the end of the arm section 51. The force sensors 20 may be attached between the end of the arm section 51 and the gripping section. The gripping section may be configured to have, for example, a plurality of finger sections (claw sections) that can grip the article with these finger sections. Alternatively, the gripping section may grip the article with any gripping means.

[0015] The transport arm 50 is controlled by the control device 60. The gripping part of the transport arm 50 may be replaceable. The transport arm 50 may be a multi-axis robot having multiple rotating arm parts 51 as described above. Alternatively, the transport arm 50 may be an articulated robot having multiple joints. The transport arm 50 may be an arm that transports products manufactured in a factory, for example, in a manufacturing plant. The weight measuring system 1 can measure the weight of an item while it is being transported by the transport arm 50. In addition, the transport arm 50 may be an arm that sorts and transports items other than factory products, such as agricultural products and various raw materials. The transportable load of the transport arm 50 is arbitrary.

[0016] The transfer arm 50 may be equipped with an acceleration sensor (not shown). In that case, the acceleration sensor can be attached, for example, to the end or the gripping part of the transfer arm 50. Alternatively, instead of or in addition to the acceleration sensor, an encoder may be attached to the motor of the transfer arm 50 to detect the rotation angle. The acceleration generated in the gripping part of the transfer arm 50 can be derived using the output signal of the acceleration sensor or the output signal of the encoder.

[0017] The force sensor 20 can be attached to the transfer arm 50 that transfers the article. The position where the force sensor 20 is attached may be, for example, between the gripping part of the transfer arm 50 and the arm part 51. Thereby, the force applied to the article gripped by the gripping part can be detected. The force sensor 20 is, for example, a six-axis force sensor, and can detect and output the magnitude of the force in the respective axial directions of the X-axis, Y-axis, and Z-axis (including the + direction and - direction), and the magnitude of the rotational moment about the X-axis, the rotational moment about the Y-axis, and the rotational moment about the Z-axis (including the + direction and - direction). However, the type of the force sensor 20 is not limited to this. The measurement ability (measurable range) of the force sensor 20 can be arbitrarily selected according to the transfer arm 50 to be attached.

[0018] Next, the information processing apparatus 10 will be described. The control unit 11 of the information processing apparatus 10 includes an acquisition unit 111, a weight derivation unit 112, and an output unit 113. The control unit 11 may include a trajectory change unit 114, may further include a determination unit 115, and may further include a sorting unit 116.

[0019] The acquisition unit 111 includes a first acquisition unit 1111 and a second acquisition unit 1112. The first acquisition unit 1111 acquires the output signal from the force sensor 20 when the transfer arm 50 moves three-dimensionally while gripping an article. "Three-dimensionally" means including the direction synthesized by all of the X-axis, Y-axis, and Z-axis with the gravity direction as the Z-axis, and including not only the horizontal direction (XY-axis direction) or the gravity direction (Z-axis direction), but also the diagonal direction. After gripping the article, the transfer arm 50 is controlled to move the article three-dimensionally along a predetermined trajectory. That is, the transfer arm 50 can move freely not only in the horizontal direction or the gravity direction, but also in the diagonal direction. Further, the trajectory is not limited to a straight line and may be a curved motion. The trajectory is stored as a control program in the control device 60. The force sensor 20 outputs a signal corresponding to the strain of the strain body during this movement. This output signal is transmitted to the information processing device 10. The first acquisition unit 1111 acquires this output signal via the input / output IF 12.

[0020] The second acquisition unit 1112 acquires the acceleration data of the transfer arm 50 when the transfer arm 50 moves three-dimensionally while gripping an article. In particular, the second acquisition unit 1112 acquires the acceleration data of the gripping part of the transfer arm 50. The method by which the second acquisition unit 1112 acquires the acceleration data is arbitrary. For example, when the transfer arm 50 is provided with the aforementioned acceleration sensor or encoder, the second acquisition unit 1112 can acquire the acceleration data by acquiring the output signal from the acceleration sensor or encoder and performing a predetermined calculation. Alternatively, the second acquisition unit 1112 may acquire the rotational speed data of each rotation axis of the transfer arm 50 included in the control program from the control device 60 and calculate the acceleration data at the gripping part. The acquisition unit 111 inputs the output signal acquired by the first acquisition unit 1111 and the acceleration data acquired by the second acquisition unit 1112 to the weight derivation unit 112.

[0021] The weight derivation unit 112 processes the input output signal and acceleration data to derive weight data representing the weight of the object. Strictly speaking, the weight obtained from the equation of motion is mass, but since weight can be calculated by multiplying it by gravitational acceleration, it will be referred to as "weight data" or simply "weight" after calculation, rather than "mass," below. With this configuration, weight derivation can be performed even when the object is moving in three dimensions. In other words, weight can be measured while the transport operation is being carried out. Therefore, the weight measurement step that was required in conventional technology to measure weight alone can be omitted, and the work can be made more efficient.

[0022] The weight derivation unit 112 may also include an (extended) Kalman filter 1121. A Kalman filter is a computational filter used to predict a physical quantity more accurately by combining the results of solving equations of motion, such as physical laws, with measurements from sensors, in order to know the true value of a certain physical quantity. Depending on the accuracy of the force sensor 20 and the acceleration sensor, accurate weight derivation may not be possible with a single measurement. Therefore, by inputting the output signals from the force sensor 20 and the acceleration sensor into the (extended) Kalman filter 1121 and sequentially processing multiple output signals and acceleration data in a time series, weight can be derived using more accurate acceleration or velocity. With this configuration, more accurate weight derivation can be performed. As a result, accurate weight derivation can be performed even when the object is moving in three dimensions.

[0023] The output unit 113 outputs the weight data derived by the weight derivation unit 112 to the outside via the input / output IF 12. "External" means outside the weight measurement system 1. For example, the output unit 113 may output the weight data to the control device 60 of the transport arm 50. The control device 60 may then be configured to control the transport arm 50 by referring to the input weight. Alternatively, the output unit 113 may generate display data for display on an external display device 30 and output it to the display device 30.

[0024] If the transport arm 50 is controlled by process control equipment (such as a process control computer) in a manufacturing plant, the output unit 113 may output weight data to the process control equipment. The process control equipment may then be configured to control the transport arm 50 by referring to the input weight. The following description will focus on the case where the transport arm 50 is controlled by the control device 60, but the same applies when the transport arm 50 is controlled by process control equipment.

[0025] The weight measurement system 1 may select a control signal for the transport arm 50 and output it to the control device 60 by referring to the weight derived by the weight extraction unit 112. In that case, the control device 60 controls the transport arm 50 using the control signal received from the weight measurement system 1. Such an example is described below.

[0026] The weight measurement system 1 may include a trajectory changing unit 114. The trajectory changing unit 114 changes the trajectory of the gripping part of the transport arm 50 by referring to weight data. In other words, the trajectory changing unit 114 changes the destination of the gripped item by referring to weight data. This will be explained with reference to Figure 3. Figure 3 is an example of a schematic plan view from above of the site where the transport arm 50 transports an item. In Figure 3, the item 40 is sequentially sent on the conveyor 70 from the upper right to the left of the figure and reaches the front of the transport arm 50 shown in the upper left. The transport arm 50 transports the item 40 to one of the destinations 81, 82, or 83 shown at the bottom of the figure. The procedure will be explained below.

[0027] The transport arm 50 detects an item 40 from an image captured by, for example, a camera (not shown), and grasps the item 40 with its gripping unit 52. Then, while gripping the item 40, the transport arm 50 moves the gripping unit 52 along a predetermined trajectory A. While the gripping unit 52 moves along trajectory A, the output signal from the force sensor 20 and acceleration data are processed by the weight derivation unit 112 of the information processing device 10 and output as weight. The trajectory changing unit 114 acquires this weight and changes (selects) the trajectory for moving the gripping unit 52 according to the weight category. The trajectory changing unit 114 then outputs the selected trajectory data to the control device 60 of the transport arm 50. The trajectory data may be a program or a trajectory number. The control device 60 controls the transport arm 50 by referring to the received trajectory data.

[0028] In the example shown in Figure 3, the weight categories of the items 40 are pre-divided into three categories: Category 1, Category 2, and Category 3. If the weight of item 40 corresponds to Category 1, the trajectory changing unit 114 changes the trajectory after trajectory A to trajectory B1, that is, it selects trajectory B1 as the trajectory after trajectory A. The output unit 113 then outputs trajectory data representing the changed trajectory B1 to the control device 60. "Changing" may also mean selecting one of the predetermined trajectories B1, B2, or B3. Alternatively, the output unit 113 may output a signal indicating trajectory B1 as trajectory data to the control device 60. The control device 60 holds a control program unit that realizes trajectory B1, and may control the transport arm 50 with that program.

[0029] Similarly, if the weight of the item 40 corresponds to the second category, the trajectory changing unit 114 changes the trajectory after trajectory A to trajectory B2. Also, if the weight of the item 40 corresponds to the third category, the trajectory changing unit 114 changes the trajectory after trajectory A to trajectory B3. The changes are output to the control device 60. Then, at the end of each trajectory, the gripping unit 52 releases the item 40, and the item 40 is transported to one of the predetermined transport destinations 81, 82, or 83.

[0030] In the example shown in Figure 3, the weight of the items 40 is divided into three categories to determine the destinations 81, 82, and 83. However, the method of changing the destination based on weight is not limited to this. For example, if an item 40 is deemed acceptable if its weight falls within a predetermined range, the acceptable items may be transported to a predetermined packaging container, while the unacceptable items may be transported to an unacceptable items storage area. The acquisition unit 111 may also count the number of acceptable items 40. When a predetermined number of acceptable items have been collected, the acquisition unit 111 can communicate with the process control equipment, which can then control the process control equipment to move the packaging containers to the shipping space.

[0031] The acquisition unit 111 may further acquire the type of item 40. The trajectory changing unit 114 may change the trajectory of the gripping part 52 of the transport arm 50 by referring to the type of item 40. For example, the acquisition unit 111 may acquire the type of item 40 by image analysis from an image of the item 40 captured by a camera or the like (not shown). The acquisition unit 111 may be equipped with a machine model that has been pre-trained with images of several types of items, and the type of item 40 may be identified by that machine model. With such a configuration, the transport destination (transport position) can be changed by taking into account not only the weight of the item 40 but also the type of item 40.

[0032] The weight measurement system 1 may include a determination unit 115. The determination unit 115 determines whether the weight data meets a predetermined weight standard. The weight standard is, for example, that the item 40, such as a product or agricultural product, is below a certain weight, above a certain weight, or between a certain weight and a certain weight. The weight standard may be obtained, for example, by the acquisition unit 111 from process control equipment, or by the user inputting the weight standard from the input unit of the information processing device 10. The trajectory changing unit 114 may change the trajectory of the gripping unit 52 by referring to the determination result of the determination unit 115. With this configuration, the system can determine whether the item passes or fails based on the weight standard, and the trajectory changing unit 114 can transport the item 40 to a predetermined destination according to the determination result.

[0033] The weight measurement system 1 may include a sorting unit 116. The sorting unit 116 sorts the items 40 by type by referring to the weight data. For example, when multiple types of items 40 are flowing, the sorting unit 116 grasps each item 40, measures its weight, and sorts the items 40 by type based on their weight. The trajectory changing unit 114 may change the trajectory of the gripping unit 52 by referring to the sorting results of the sorting unit 116. With this configuration, the types of items 40 can be sorted by weight, and the trajectory changing unit 114 can transport the items 40 to a predetermined destination according to the sorting results.

[0034] The input / output IF12 of the information processing device 10 is an interface for outputting information to the outside or acquiring (inputting) information from the outside. The input / output IF12 may be a wireless communication unit such as Wi-Fi® or Bluetooth®, or a wired communication unit such as a USB input / output terminal.

[0035] The processor 13 can be configured using, for example, at least one general-purpose processor such as an MPU (Micro Processing Unit) or CPU (Central Processing Unit). Alternatively, the processor 13 may include a dedicated processor composed of an ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or PLD (Programmable Logic Device).

[0036] Memory 14 may include multiple types of memory, such as ROM (Read Only Memory) and RAM (Random Access Memory). Memory 14 may also include internal or external memory such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). As an example, the control unit 11 implements the functions of the acquisition unit 111, weight derivation unit 112, output unit 113, trajectory modification unit 114, determination unit 115, and sorting unit 116 by loading various control programs recorded in the ROM of memory 14 into the RAM and executing them. Memory 14 may also store at least one of the following: weight data, trajectory data modified by the trajectory modification unit 114, determination results from the determination unit 115, and sorting results from the sorting unit 116.

[0037] Memory 14 may store various programs. For example, it may store custom programs according to the operating environment of the weight measurement system 1, such as a trajectory program for moving the item 40 to a transport position corresponding to the site where the transport arm 50 is working, a program for determining or classifying weight data using thresholds, and a data processing program according to the type of force sensor 20. The output unit 113 may output data stored in memory 14 to the display device 30.

[0038] The above program can be created using commonly used programming languages. Examples of programming languages ​​include C#, C++, and Python. Using these programming languages ​​increases compatibility with the control program used in the control device 60 of the transport arm 50, making it easier to connect to the existing transport arm 50's control device 60. Furthermore, since these languages ​​can also be used with robot development platforms such as ROS and ROS2, there is the added benefit of high compatibility with transport arms 50 developed on such platforms.

[0039] The weight measurement system 1 may be connected to an optional display device 30. The display device 30 may display at least one of the following stored in the memory 14: the measured weight data, the trajectory data modified by the trajectory modification unit 114, the determination result of the determination unit 115, and the sorting result of the sorting unit 116. The display device 30 may be the display of a personal computer incorporating the information processing device 10. The memory 14 may be the memory of a personal computer. Thresholds and the like may be configured to be input by the user as appropriate via the display device 30.

[0040] According to the weight measurement system 1 having the above configuration, accurate weight measurement is possible while moving the object to be measured in three dimensions using the force sensor 20, and by appropriately selecting the force sensor 20 according to the capacity of the transport arm 50, a versatile weight measurement technology applicable to objects of various weights can be realized. Furthermore, for example, the movement of the transport arm 50 can be controlled based on the measured weight.

[0041] Next, the weight measurement method S1 according to this embodiment will be described. Figure 4 is a flowchart showing the flow of the weight measurement method S1 according to this embodiment. As shown in the figure, the weight measurement method S1 includes steps S11 to S14.

[0042] Step S11 is a first acquisition step (also called the first acquisition process) in which the transport arm 50 that transports the item 40 moves in three dimensions while gripping the item 40, and the output signal from the force sensor 20 attached to the transport arm 50 is acquired. The first acquisition step S11 is performed by the first acquisition unit 1111 described above.

[0043] Step S12 is a second acquisition step (also called the second acquisition process) in which acceleration data of the transport arm 50 is acquired when the transport arm 50 moves three-dimensionally while gripping the item 40. The second acquisition step S12 is performed by the second acquisition unit 1112 described above.

[0044] Step S13 is a derivation step in which the output signal from the force sensor 20 and the acceleration data calculated from the acceleration sensor or encoder are processed to derive weight data representing the weight of the item 40. Derivation step S13 is performed by the weight derivation unit 112 described above.

[0045] Step S14 is an output step in which weight data is output to an external source. Output step S14 is performed by the output unit 113 described above. Alternatively, in output step S14, the weight data may be output to the control device 60 of the transport arm 50.

[0046] The weight measurement method S1 may further include a trajectory modification step in which the trajectory of the gripping portion 52 of the transport arm 50 is modified by referring to the weight data. In this case, the output step S14 may output trajectory data representing the modified trajectory to the control device 60 of the transport arm 50.

[0047] Furthermore, in the weight measurement method S1, the trajectory of the gripping part 52 of the transport arm 50 may be changed in the trajectory changing step by referring to the type of article 40. In that case, the type of article 40 may be acquired in the first acquisition step S11.

[0048] Furthermore, the weight measurement method S1 may further include a determination step to determine whether the weight data meets a predetermined weight standard. In that case, the trajectory may be changed in the trajectory change step by referring to the determination result of the determination step.

[0049] Furthermore, the weight measurement method S1 may further include a sorting step in which the items 40 are sorted by referring to the weight data. In that case, the trajectory may be changed in the trajectory change step by referring to the sorting results of the sorting step.

[0050] According to the weight measurement method S1 described above, accurate weight measurement is possible while moving the object to be measured in three dimensions using the force sensor 20. Furthermore, by appropriately selecting the force sensor 20 according to the capacity of the transport arm 50, a versatile weight measurement technology applicable to objects of various weights can be realized. In addition, for example, the movement of the transport arm 50 can be controlled based on the measured weight.

[0051] [Embodiment 2] Next, Embodiment 2 of the present invention will be described with reference to the drawings. Figure 5 is a block diagram showing the configuration of the weight measurement system 1A according to Embodiment 2. In the following description, the differences from the configuration of Embodiment 1 will be the focus, and the same functions as those described in Embodiment 1 will not be described. The weight measurement system 1A according to Embodiment 2 is a system that measures the weight of a gripped object by processing only the output signal from the force sensor 20. In other words, it is not necessarily required to have a second acquisition unit that acquires acceleration data from an acceleration sensor or the like, as described in Embodiment 1. However, by providing a second acquisition unit that acquires acceleration data, it becomes possible to perform weight measurement with even greater accuracy. In this case, the force sensor 20 is attached to the gripping unit 52 (see Figure 3). More specifically, it is attached between the end of the arm unit 51 and the gripping unit 52. In other words, the force sensor 20 is configured to directly receive the weight of the object gripped by the gripping unit 52 and output a sensor signal to the information processing device 10.

[0052] As shown in Figure 5, the control unit 11A of the information processing device 10A of the weight measurement system 1A includes a control signal acquisition unit 117. This control signal acquisition unit 117 will be described later. The other configurations of the weight measurement system 1A are the same as those of the weight measurement system 1 of Embodiment 1.

[0053] Similar to Embodiment 1, the gripping portion 52 is controlled to move in three dimensions. The gripping portion 52 may be controlled to move in any three dimensions. However, when measuring the weight of an object using only the output signal from the force sensor 20, it is expected that the accuracy of weight measurement will be improved if the gripping portion 52 moves according to certain conditions. For example, the arm portion 51 may be controlled so that the gripping portion 52 moves along a predetermined trajectory. Alternatively, the arm portion 51 may be controlled so that the gripping portion 52 moves with a predetermined acceleration.

[0054] The weight deriving unit 112 may, for example, process the output signal from the force sensor 20 when the gripping unit 52 is controlled to move along a predetermined trajectory to derive weight data of the gripped item. This also includes cases where the gripping unit is controlled to move along a predetermined trajectory and with a predetermined acceleration.

[0055] In this case, the weight derivation unit 112 may derive weight data by referring to the correlation between the output signal from the force sensor acquired when an arbitrary item is transported, when the gripping unit 52 is controlled to move along a predetermined trajectory, and the weight data corresponding to the output signal. This correlation may be determined by conducting transport tests in advance under various patterns. For example, various items of different shapes and weights are moved along a predetermined trajectory and output signals are acquired from the force sensor 20. Then, a large amount of data is acquired on what kind of output signal is acquired when an item of a certain shape and weight is moved along a predetermined trajectory. Then, a calculation formula is determined in which the weight data of an item is calculated when a predetermined output signal is substituted under various transport conditions. The calculation formula thus obtained is a type of correlation. The calculation formula may be a calculation formula based on a linear model, a calculation formula based on a quadratic function model, a calculation formula based on a polynomial model, etc.

[0056] Alternatively, a reference table may be created that summarizes the combinations of transport conditions and output signals, along with the corresponding weight data, for various transport conditions. Transport conditions include, for example, the trajectory of the gripping unit and its acceleration. Such a reference table is also a type of correlation.

[0057] Alternatively, a correlation (or calculation formula) may be obtained using a machine model. For example, a large amount of measured data (training data) may be collected by combining predetermined transport conditions, including a defined trajectory, the measured output signal at that time, and weight data, and a machine model that estimates the weight data of an item may be trained using this training data. By inputting the output signal at that time into the machine model trained for each transport condition, the estimated weight data is output. An algorithm including the parameters built into the trained machine model is also considered a calculation formula. The above correlation may be stored, for example, in memory 14, or in an external database or memory.

[0058] Furthermore, when the weight extraction unit 112 derives weight data of an item when the gripping unit 52 is controlled to move along a predetermined trajectory and with predetermined acceleration, it is sufficient to determine a calculation formula that, for example, calculates the weight data of the item when a predetermined output signal is substituted under the predetermined transport conditions of trajectory and acceleration. As mentioned above, a reference table or a mechanical model may also be used as a correlation instead of a calculation formula.

[0059] Furthermore, the weight extraction unit 112 may process the output signal from the force sensor 20 when the gripping unit 52 is controlled to move with a predetermined acceleration, for example, to derive weight data of the gripped item. This also includes cases where the gripping unit is controlled to move with a predetermined acceleration and along a predetermined trajectory.

[0060] In this case as well, the weight derivation unit 112 may derive weight data by referring to the correlation between the weight of an arbitrary item and the output signal corresponding to that item, for example, when the gripping unit 52 is controlled to move at a predetermined acceleration. This correlation may be determined by conducting transport tests in advance under various patterns. For example, various items of different shapes and weights are moved at a predetermined acceleration and output signals are obtained from the force sensor 20. If the direction of acceleration changes, that condition may also be included. Then, a large amount of data is obtained on what kind of output signal is obtained when an item of a certain shape and weight is moved at a certain acceleration. Then, a calculation formula is determined in which the weight data of an item is calculated when a predetermined output signal is substituted under various transport conditions. The calculation formula thus obtained is a type of correlation. The calculation formula may be a calculation formula based on a linear model, a calculation formula based on a quadratic function model, a calculation formula based on a polynomial model, etc.

[0061] Furthermore, a reference table may be created that summarizes the combination of transport conditions and output signals, along with the corresponding weight data, for various transport conditions. Transport conditions include, for example, the acceleration of the gripping part, the direction of acceleration, or both, and the trajectory of the movement of the gripping part. Such a reference table is also a type of correlation.

[0062] Alternatively, a correlation (or calculation formula) may be obtained using a machine model. For example, a large amount of measured data (training data) may be collected by combining predetermined transport conditions, including a defined acceleration, with the measured output signal at that time and weight data, and a machine model that estimates the weight data of an item may be trained using this training data. By inputting the output signal at that time into the machine model trained for each transport condition, the estimated weight data is output. The algorithm, including the parameters built into the trained machine model, is also considered a calculation formula. The above correlation may be stored in memory 14, or in external memory, for example.

[0063] Furthermore, when the weight extraction unit 112 derives weight data of an item when the gripping unit 52 is controlled to move with a predetermined acceleration and trajectory, it is sufficient to determine a calculation formula that, for example, calculates the weight data of an item when a predetermined output signal is substituted under predetermined transport conditions of acceleration and trajectory. As mentioned above, a reference table or a mechanical model may also be used as a correlation instead of a calculation formula.

[0064] The weight derivation unit 112 may derive weight data using one or more of the above correlations (calculation formulas). In other words, the above correlation used by the weight derivation unit 112 may be at least one of the following: a calculation formula using a linear model, a calculation formula using a quadratic function model, a calculation formula using a polynomial model, and a calculation formula obtained by machine learning.

[0065] The weight measurement system 1A may include a control signal acquisition unit 117. The control signal acquisition unit 117 acquires a control signal that controls the movement of the gripping unit 52. This control signal is a signal transmitted by the control device 60 described in Embodiment 1 to the transport arm 50. The control signal acquisition unit 117 may acquire this signal. The control signal acquisition unit 117 notifies the first acquisition unit 1111 that it has acquired this control signal, and the first acquisition unit 1111, upon receiving this notification, acquires the output signal of the force sensor 20 from that point onward. It then transmits the acquired output signal to the weight derivation unit 112. The weight derivation unit 112 processes the output signal of the force sensor 20 from the point onward when this control signal was acquired to derive weight data. With this configuration, the weight derivation unit 112 can efficiently start data processing.

[0066] In this case, the control signal may include an identification signal that identifies what kind of control to perform. The identification signal may be, for example, an identification signal indicating that it is a control signal to control the gripping unit 52 to move along a predetermined trajectory, or an identification signal indicating that it is a control signal to control the gripping unit 52 to move at a predetermined acceleration. Alternatively, the identification signal may be an identification signal indicating which transport condition from the aforementioned reference table to use for control, such as the type of transport condition. The control signal acquisition unit 117 transmits the identification signal to the weight derivation unit 112. By referring to the identification signal, the weight derivation unit 112 can easily determine which method to use to derive the weight and can process the data quickly.

[0067] Next, the weight measurement method S2, which is performed using the weight measurement system 1A, will be described with reference to the drawings. Figure 6 is a flowchart showing the flow of the weight measurement method S2. As shown in the figure, the weight measurement method S2 includes steps S21 to S26.

[0068] Step S21 is an acquisition step in which the control signal acquisition unit 117 acquires a control signal to move the gripping unit 52. Step S22 is a first acquisition step in which the first acquisition unit 1111 acquires an output signal from the force sensor 20 attached to the gripping unit 52 when the gripping unit 52 of the transport arm 50, which grips and transports an item, moves three-dimensionally while gripping an item. Next, the weight derivation unit 112 performs a weight derivation step in which it processes the output signal to derive weight data representing the weight of the item, but the way the weight derivation step is performed differs depending on the pattern in which the gripping unit 52 moves. There are multiple patterns in which the gripping unit 52 moves three-dimensionally while gripping an item, such as a pattern in which it moves three-dimensionally along a predetermined trajectory, or a pattern in which it moves three-dimensionally with a predetermined acceleration.

[0069] Step S23 is a weight derivation process when the gripping unit 52 is controlled to move three-dimensionally along a predetermined trajectory. In other words, step S23 is a derivation process in which the weight derivation unit 112 acquires the output signal from the force sensor 20 when the gripping unit 52 moves three-dimensionally along a predetermined trajectory, processes it, and derives the weight data of the item.

[0070] Step S24 is a weight deriving process when the gripping part 52 is controlled to move three-dimensionally with a predetermined acceleration. In other words, step S24 is a deriving process in which the weight deriving unit 112 acquires the output signal from the force sensor 20 when the gripping part 52 moves three-dimensionally with a predetermined acceleration, processes it, and derives the weight data of the item.

[0071] Step S25 is a weight derivation process when the gripping part 52 is controlled to move three-dimensionally along a predetermined trajectory and with predetermined acceleration. In other words, step S25 is a derivation process in which the weight derivation unit 112 acquires the output signal from the force sensor 20 when the gripping part 52 moves three-dimensionally along a predetermined trajectory and with predetermined acceleration, processes the output signal, and derives the weight data of the item.

[0072] Step S26 is an output process in which the output unit 113 outputs the weight data derived by the weight derivation unit 112 to the outside.

[0073] However, it is not necessary to perform all steps. For example, step S21 does not need to be performed. Also, steps S23 through S25 can be selected and executed.

[0074] According to the weight measurement system 1A or weight measurement method S2 described above, accurate weight measurement is possible while moving the object to be measured in three dimensions using the force sensor 20. Furthermore, by appropriately selecting the force sensor 20 according to the capacity of the transport arm 50, a versatile weight measurement technology applicable to objects of various weights can be realized.

[0075] [Examples of implementation using software] The functions of the information processing devices 10 and 10A (hereinafter referred to as "devices") are programs that cause the devices to function as computers, and these programs can be realized by programs that cause each control block of the devices (especially each part included in the control units 11 and 11A) to function as a computer.

[0076] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., memory) as hardware for executing the program. By executing the program using this control device and storage device, the functions described in each of the embodiments are realized.

[0077] The above program may be recorded on one or more computer-readable recording media, not temporary ones. These recording media may or may not be provided by the above device. In the latter case, the program may be supplied to the above device via any wired or wireless transmission medium.

[0078] Furthermore, some or all of the functions of each of the above control blocks can also be realized by logic circuits. For example, an integrated circuit in which logic circuits functioning as each of the above control blocks are formed is also included in the scope of the present invention. In addition, it is also possible to realize the functions of each of the above control blocks by, for example, a quantum computer.

[0079] 〔summary〕 (Aspect 1) A weight measurement system comprising: a force sensor attachable to a transport arm for transporting an item; a first acquisition unit that acquires an output signal from the force sensor when the transport arm moves three-dimensionally while gripping the item; a second acquisition unit that acquires acceleration data of the transport arm when the transport arm moves three-dimensionally while gripping the item; a weight derivation unit that processes the output signal and the acceleration data to derive weight data representing the weight of the item; and an output unit that outputs the weight data to the outside. With the above configuration, it is possible to accurately measure the weight of the object being measured while moving it in three dimensions using a force sensor, and a versatile weight measurement technology can be realized that is applicable to objects of various weights.

[0080] (Aspect 2) The weight measurement system according to embodiment 1, wherein the output unit outputs the weight data to the control device of the transport arm. With the above configuration, the transport arm can be controlled by referring to weight data.

[0081] (Aspect 3) A weight measuring system according to embodiment 1 or 2, further comprising a trajectory changing unit that changes the trajectory of the gripping portion of the transport arm by referring to the weight data, and an output unit that outputs trajectory data representing the changed trajectory to the control device of the transport arm. With the above configuration, the trajectory of the transport arm can be changed by referring to weight data.

[0082] (Aspect 4) The weight measuring system according to embodiment 3, wherein the first acquisition unit further acquires the type of the article, and the trajectory changing unit changes the trajectory in which the gripping part of the transport arm moves, with reference to the type of article. With the above configuration, the trajectory of the transport arm can be changed by referring to the type and weight data of the items.

[0083] (Aspect 5) The weight measurement system according to embodiment 3, further comprising a determination unit that determines whether the weight data meets a predetermined weight standard, and the trajectory changing unit changes the trajectory by referring to the determination result of the determination unit. With the above configuration, the trajectory of the transport arm can be changed depending on whether or not the weight of the item meets the weight specifications.

[0084] (Aspect 6) The weight measurement system according to any one of embodiments 3 to 5, wherein the output unit outputs at least one of the weight data, the modified trajectory, and the determination result of the determination unit to a display device. With the above configuration, users can verify the operation of the weight measurement system.

[0085] (Aspect 7) An information processing device comprising: a first acquisition unit that acquires an output signal from a force sensor attached to a transport arm when the transport arm moves three-dimensionally while gripping the item; a second acquisition unit that acquires acceleration data of the transport arm when the transport arm moves three-dimensionally while gripping the item; a weight derivation unit that processes the output signal and the acceleration data to derive weight data representing the weight of the item; and an output unit that outputs the weight data to the outside. With the above configuration, it is possible to accurately measure the weight of the object being measured while moving it in three dimensions using a force sensor, and a versatile weight measurement technology can be realized that is applicable to objects of various weights.

[0086] (Pattern 8) A weight measurement method comprising: a first acquisition step of acquiring an output signal from a force sensor attached to a transport arm when the transport arm moves three-dimensionally while gripping the item; a second acquisition step of acquiring acceleration data of the transport arm when the transport arm moves three-dimensionally while gripping the item; a weight derivation step of processing the output signal and the acceleration data to derive weight data representing the weight of the item; and an output step of outputting the weight data to the outside. With the above configuration, it is possible to accurately measure the weight of the object being measured while moving it in three dimensions using a force sensor, and a versatile weight measurement technology can be realized that is applicable to objects of various weights.

[0087] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0088] 1...Weight measurement system 10...Information processing device 11...Control unit 111...Acquisition unit 112...Weight extraction unit 113...Output unit 114...Trajectory modification unit 115...Determination unit 116...Sorting unit 12…Input / Output Interface 13…Processor 14…Memory 20…Force Sensor 30…Display Device 40…Item 50…Transport Arm 51…Arm Section 52…Gripping Section 60…Control Device 70...Conveyor belt 81, 82, 83...Destination

Claims

1. A force sensor that can be attached to the gripping part of a transport arm that grips and transports items, A first acquisition unit acquires the output signal from the force sensor when the gripping part moves three-dimensionally while gripping the article, A weight derivation unit that processes the output signal to derive weight data representing the weight of the article, An output unit that outputs the aforementioned weight data to the outside, A weight measurement system equipped with the following features.

2. The weight measurement system according to claim 1, wherein the weight deriving unit processes the output signal when the gripping unit is controlled to move along a predetermined trajectory to derive the weight data.

3. The weight measurement system according to claim 1, wherein the weight deriving unit processes the output signal when the gripping unit is controlled to move at a predetermined acceleration to derive the weight data.

4. The weight measurement system according to claim 2, wherein the weight deriving unit derives the weight data by referring to a predetermined correlation between the output signal from the force sensor acquired when an arbitrary item is transported, when the gripping unit is controlled to move along the predetermined trajectory, and the weight data corresponding to the output signal.

5. The weight measurement system according to claim 3, wherein the weight deriving unit derives weight data by referring to a predetermined correlation between an output signal from the force sensor acquired when an arbitrary item is transported, when the gripping unit is controlled to move at a predetermined acceleration, and weight data corresponding to the output signal.

6. The weight measurement system according to any one of claims 1 to 5, further comprising a control signal acquisition unit that acquires a control signal that controls the movement of the gripping unit, and the weight derivation unit processes the output signal from the time the control signal is acquired onward to derive the weight data.

7. The weight measurement system according to claim 4 or 5, wherein the correlation is at least one of a calculation formula based on a linear model, a calculation formula based on a quadratic function model, a calculation formula based on a polynomial model, and a calculation formula obtained by machine learning.

8. The system further includes a second acquisition unit that acquires acceleration data of the transport arm when the gripping portion of the transport arm moves three-dimensionally while gripping the article. The weight derivation unit processes the output signal and the acceleration data to derive weight data representing the weight of the article. The weight measurement system according to claim 1.

9. The weight measurement system according to claim 8, wherein the output unit outputs the weight data to the control device of the transport arm.

10. The weight measuring system according to claim 9, further comprising a trajectory changing unit that changes the trajectory of the gripping portion of the transport arm by referring to the weight data, and an output unit that outputs trajectory data representing the changed trajectory to the control device of the transport arm.

11. The weight measuring system according to claim 10, wherein the first acquisition unit further acquires the type of article, and the trajectory changing unit changes the trajectory in which the gripping part of the transport arm moves, with reference to the type of article.

12. The weight measurement system according to claim 10, further comprising a determination unit that determines whether the weight data meets a predetermined weight standard, and the trajectory changing unit changes the trajectory by referring to the determination result of the determination unit.

13. The weight measurement system according to claim 12, wherein the output unit outputs at least one of the weight data, the modified trajectory, and the determination result of the determination unit to a display device.

14. A first acquisition unit acquires an output signal from a force sensor attached to a transfer arm that grasps and transports an item, when the gripping part of the transfer arm moves three-dimensionally while grasping the item. A weight derivation unit that processes the output signal to derive weight data representing the weight of the article, An output unit that outputs the aforementioned weight data to the outside, An information processing device equipped with the following features.

15. The system further includes a second acquisition unit that acquires acceleration data of the transport arm when the gripping unit moves three-dimensionally while gripping the article, The weight derivation unit processes the output signal and the acceleration data to derive weight data representing the weight of the article. The information processing apparatus according to claim 14.

16. A first acquisition step involves acquiring an output signal from a force sensor attached to a gripping part of a transport arm that grips and transports an item, when the gripping part moves three-dimensionally while gripping the item. A weight derivation step of processing the output signal to derive weight data representing the weight of the article, An output process for outputting the aforementioned weight data to an external source, A method of measuring weight, including the following.

17. The process further includes a second acquisition step of acquiring acceleration data of the transport arm when the gripping part moves three-dimensionally while gripping the article, In the weight derivation step, the output signal and the acceleration data are processed to derive weight data representing the weight of the article. The weight measurement method according to claim 16.

Images