Sensor system using wireless power transfer

Abstract

To raise workability and a degree of freedom of an installation location and to appropriately acquire data of a high frequency band.SOLUTION: A sensor system 1 using wireless power feeding comprises: a sensor unit 4 which is integrally movable with a movable apparatus 2; and a power feeding unit 14 which wirelessly feeds power. The sensor unit comprises: a power reception unit 9 which receives the power from the power feeding unit; a storage unit 10 which stores the power received by the power reception unit; a sensor unit 11 which uses the power to be supplied from the storage unit as operation power and acquires data of a high frequency band corresponding to the movable apparatus at sampling rate higher than a predetermined value; and a communication unit 13 which transmits the data acquired by the sensor unit to a data processing unit by wireless communication.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a sensor system using wireless power supply.

Background Art

[0002] Conventionally, there has been a problem that abnormal stops or failures of production equipment occur due to wear or damage of movable devices, resulting in a decrease in productivity. As a means to solve this problem, an acceleration sensor that detects vibrations in a high-frequency band (for example, 20 kHz or higher) is installed in a movable device, and data in the high-frequency band indicating the vibration characteristics of the movable device is acquired from the acceleration sensor to grasp the state of the production equipment. As an acceleration sensor for detecting the vibration of a movable device, a wired small sensor or a wireless large sensor equipped with a rechargeable battery is used.

[0003] In the case of a wired sensor, there is a risk of wire disconnection, and there are problems that the installation location, moving speed, and moving range are limited in order to avoid disconnection. Also, when replacing the sensor, work such as wiring routing is required. On the other hand, in the case of a wireless sensor, battery replacement work and charging work are required, and there is a problem that the installation location is limited to a position where the battery can be attached and detached. Also, data cannot be acquired at a high sampling rate, and there is a problem that data in the high-frequency band cannot be appropriately acquired. For example, Patent Document 1 discloses a configuration in which a power receiving unit is installed in a sensor unit having a wireless sensor, and wireless power supply is performed from an external power supply unit to the power receiving unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 describes how wireless power supply to wireless sensors eliminates the problems associated with wiring for wired sensors, while also eliminating the need for battery replacement and charging, thus resolving the issues of workability and flexibility in installation location associated with batteries. However, Patent Document 1 does not anticipate acquiring high-frequency data at a high sampling rate, and the problem of not being able to properly acquire high-frequency data remains unresolved.

[0006] This invention has been made in view of the above circumstances, and its purpose is to provide a sensor system that utilizes wireless power supply, which improves workability and flexibility in installation location, and can appropriately acquire high-frequency band data. [Means for solving the problem]

[0007] The invention described in claim 1 comprises a sensor unit (4) that moves integrally with a movable device, and a power supply unit (14) that wirelessly supplies power. The movable device moves back and forth between the first and second positions, with one cycle consisting of moving from the first position to the second position, stopping at the second position, moving from the second position to the first position, and stopping at the first position. The aforementioned sensor unit is By having the movable device stopped at the first position and facing the power supply unit, The system includes a power receiving unit (9) that receives power from the power supply unit, a storage unit (10) that stores the power received by the power receiving unit, a sensor unit (11) that uses the power supplied from the storage unit as operating power and acquires high-frequency band data corresponding to the movable device at a sampling rate higher than a predetermined value, and a communication unit (13) that transmits the data acquired by the sensor unit to a data processing unit via wireless communication. The sensor unit acquires the data during the period when the movable device moves from the second position to the first position, based on timing set by a timer that defines the timing when the movable device starts moving from the second position to the first position, and timing set by a timer that defines the data acquisition time. The communication unit transmits the data to the data processing unit by wireless communication during the period when the movable device moves from the second position to the first position.

[0008] By wirelessly powering the sensor unit that acquires high-frequency data corresponding to moving equipment at a sampling rate higher than a predetermined value, the need for conventional battery replacement and charging is eliminated, resolving the issues of workability and installation flexibility associated with batteries. By transmitting the high-frequency data acquired by the sensor unit to the data processing unit via wireless communication, high-frequency data can be acquired appropriately. [Brief explanation of the drawing]

[0009] [Figure 1] Diagram illustrating the configuration of one embodiment of the present invention. [Figure 2] Functional block diagram [Figure 3] Timing chart [Modes for carrying out the invention]

[0010] One embodiment will be described below with reference to the drawings. As shown in Figure 1, the sensor system 1, which utilizes wireless power supply, is installed, for example, as part of a production facility. The movable device 2 moves back and forth linearly along a fixed, straight rail 3 between a first position and a second position in the directions of arrows A1 and A2. In Figure 1, the state in which the movable device 2 is stopped at the first position is shown by a solid line, and the state in which the movable device 2 is stopped at the second position is shown by a dashed line. In this embodiment, a rectangular parallelepiped movable device 2 is shown as an example, but the shape of the movable device 2 is not limited to a rectangular parallelepiped.

[0011] The movable device 2 moves back and forth in a linear fashion, with one cycle consisting of moving from the first position to the second position, stopping at the second position, moving from the second position to the first position, and stopping at the first position. The movement from the first position to the second position, i.e., the movement in the direction of arrow A1, is called forward movement, and the movement from the second position to the first position, i.e., the movement in the direction of arrow A2, is called backward movement. The time required for the movable device 2 to move forward and the time required for it to move backward may be the same or different. The time the movable device 2 is stopped at the second position and the time it is stopped at the first position may be the same or different. A sensor unit 4 is fixed to one side of the movable device 2, and the movable device 2 and the sensor unit 4 move back and forth in a linear fashion as a single unit.

[0012] The power supply unit 5 is fixedly positioned at the location facing the sensor unit 4 when the movable device 2 is in its first position. The power supply unit 5 wirelessly supplies power to the sensor unit 4 from an external source. The wireless power supply standard may be, for example, the Qi standard. In the case of the Qi standard, the distance and planar positional displacement between the sensor unit 4 and the power supply unit 5 must be less than a few centimeters. The wireless power supply method may be electromagnetic induction, magnetic field resonance, or electromagnetic wave radiation. Wireless power supply by electromagnetic wave radiation is, for example, microwave power supply.

[0013] The sensor unit 4 and the power supply unit 5 are the same size, for example, with dimensions of 40 mm in the x-direction, 40 mm in the y-direction, and 15 mm in the z-direction. When the sensor unit 4 and the power supply unit 5 are facing each other, the distance between them is approximately 10 mm. In Figure 1, the distance between them is exaggerated for illustrative purposes, and the ratio of the sizes of the sensor unit 4 and the power supply unit 5 to the distance between them is illustrated differently from the real world. A PC terminal 7 (corresponding to the data processing unit) is connected to the power supply unit 5 via a wired cable 6.

[0014] As shown in Figure 2, the sensor unit 4 comprises a CPU (Central Processing Unit) 8, a power receiving unit 9, a capacitor 10, a sensor unit 11, a memory 12, and a communication unit 13. The power supply unit 5 comprises a power supply unit 14.

[0015] The power supply unit 14 wirelessly supplies power from an external source to the power receiving unit 9. The power receiving unit 9 receives power wirelessly supplied from the power supply unit 14. The capacitor 10 stores the power received by the power receiving unit 9. When the power stored in the capacitor 10 reaches a threshold, power is supplied from the capacitor 10 to the CPU 8, sensor unit 11, memory 12, and communication unit 13. The threshold is a value that allows the CPU 8, sensor unit 11, memory 12, and communication unit 13 to perform a series of processes described later, and can be set appropriately, for example, through experiments or simulations. In Figure 2, the power path is shown by a dashed line.

[0016] The CPU 8 operates using the power supplied from the capacitor 10 as the operating power, outputs control commands to the power receiving unit 9, the sensor unit 11, the memory 12, and the communication unit 13, and controls the operation of the sensor unit 4. In FIG. 2, the path of the control command is shown by a solid line.

[0017] The sensor unit 11 includes an acceleration sensor and is arranged to be able to detect vibrations generated by the reciprocating linear movement of the movable device 2. The sensor unit 11 operates using the power supplied from the capacitor 10 as the operating power. When a data acquisition start command is input as a control command from the CPU 8, it starts a data acquisition operation to acquire vibration data in a high-frequency band indicating the vibration characteristics of the movable device 2 at a sampling rate higher than a predetermined value, and outputs the acquired vibration data in the high-frequency band to the memory 12. The sensor unit 11 ends the data acquisition operation when a data acquisition end command is input as a control command from the CPU 8. The predetermined value may be determined according to, for example, the quality assurance specifications required by the sensor system 1.

[0018] The memory 12 operates using the power supplied from the capacitor 10 as the operating power. When a data holding command is input as a control command from the CPU 8, it inputs vibration data in a high-frequency band from the sensor unit 11 and temporarily holds the input vibration data in the high-frequency band.

[0019] The communication unit 13 operates using the power supplied from the capacitor 10 as the operating power. When a data transmission command is input as a control command from the CPU 8, it reads out the vibration data in the high-frequency band temporarily held in the memory 12 and transmits the read vibration data in the high-frequency band to the PC terminal 7 by wireless communication. The wireless communication method is, for example, a short-range wireless communication standard such as Bluetooth (registered trademark) or Bluetooth Low Energy.

[0020] Next, the operation of the above-described configuration will be described with reference to FIG. 3. The movable device 2 reciprocates linearly with one cycle being forward movement from time t1 to time t2, stopping at the second position from time t2 to time t3, backward movement from time t3 to time t7, and stopping at the first position from time t7 to time t8.

[0021] The CPU 8 has a first timer for measuring the waiting time from the start point of the forward movement of the movable device 2 to the start point of the backward movement, that is, until the start of acquisition of vibration data, and a second timer for measuring the acquisition time of the vibration data. The acquisition time of the vibration data is a time that can be arbitrarily specified within the time from the start point to the end point of the backward movement of the movable device 2. The CPU 8 starts the counting of the first timer at the start point of the forward movement of the movable device 2 (t1). When the counting of the first timer expires, that is, when it reaches the start point of the backward movement of the movable device 2, the CPU 8 outputs a data acquisition start command to the sensor unit 11 and starts the counting of the second timer. Also, the CPU 8 outputs a data transmission command to the communication unit 13.

[0022] When the sensor unit 11 receives a data acquisition start command from the CPU 8, it starts acquiring vibration data in a high-frequency band indicating the vibration characteristics of the movable device 2 (t3). The vibration data in the high-frequency band acquired by the sensor unit 11 is sequentially held in the memory 12. When the communication unit 13 receives a data transmission command from the CPU 8, it refers to the memory 12, sequentially reads out the vibration data in the high-frequency band held in the memory 12, and starts transmitting the read vibration data in the high-frequency band to the PC terminal 7 (t4).

[0023] When the counting of the second timer expires, the CPU 8 outputs a data acquisition end command to the sensor unit 11. When the sensor unit receives a data acquisition end command from the CPU 8, it ends the acquisition of vibration data in the high-frequency band (t5). When the communication unit 13 has read out all the vibration data in the high-frequency band held in the memory 12, it ends the transmission of the vibration data in the high-frequency band to the PC terminal 7 (t6). At the PC terminal 7, by analyzing the vibration data in the high-frequency band received from the sensor unit 4, it becomes possible to diagnose wear, damage, etc. of the movable device 2.

[0024] When the movable device 2 finishes retracting and stops at the first position, and the sensor unit 4 approaches the power supply unit 5 so that power can be supplied, power is supplied from the power supply unit 14 to the power receiving unit 9, and power is stored in the capacitor 10 (t7). When the movable device 2 starts moving forward and the sensor unit 4 moves away from the power supply unit 5 so that power cannot be supplied, power is supplied from the power supply unit 14 to the power receiving unit 9 (t8). The above process is repeated as long as the movable device 2 continues to move back and forth in a straight line.

[0025] As described above, according to this embodiment, the following effects can be obtained. In the wireless power supply system 1, by wirelessly supplying power to a sensor unit 11 that acquires high-frequency data indicating the vibration characteristics of the movable equipment 2 at a sampling rate higher than a predetermined value, conventional battery replacement and charging work is eliminated, resolving issues related to workability and flexibility of installation location associated with batteries. By transmitting the high-frequency data acquired by the sensor unit 11 to the PC terminal 7 via wireless communication, high-frequency data can be acquired appropriately.

[0026] The movable device 2 is configured to receive power from the power supply unit 14 while it is stopped in the first position. This allows for stable power supply from the power supply unit 14 to the power receiving unit 9 when the power supply unit 14 and the power receiving unit 9 are facing each other.

[0027] This disclosure is described in accordance with the embodiments, but is not limited to those embodiments or structures. This disclosure also includes various modifications and variations within the equivalence range. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

[0028] As an example of a sensor unit that acquires high-frequency data corresponding to movable equipment at a sampling rate higher than a predetermined value, an acceleration sensor that acquires vibration data showing the vibration characteristics of movable equipment was given. However, it may also be applied to acoustic emission (AE) sensors that detect the phenomenon in which elastic energy stored inside a material is released as sound waves (elastic waves) when the material deforms or breaks, or to sensors that detect grooves, scratches, etc. on rails. Since the frequency band of AE sensors is several tens of kHz to several MHz, which is higher than the frequency band of acceleration sensors, they can handle even higher frequency bands.

[0029] Although an example has been given of a configuration in which power is supplied from the power supply unit 14 to the power receiving unit 9 when the movable device 2 is stopped in the first position, it is also possible to configure the system so that power is supplied from the power supply unit 14 to the power receiving unit 9 when the movable device 2 is stopped in the second position, by positioning the power supply unit 5 at the part facing the sensor unit 4 when the movable device 2 is in the second position. Alternatively, it is also possible to configure the system so that power is supplied from the power supply unit 14 to the power receiving unit 9 in both the state when the movable device 2 is stopped in the first position and the state when the movable device 2 is stopped in the second position, by positioning the power supply unit 5 at two locations: the part facing the sensor unit 4 when the movable device 2 is in the first position and the part facing the sensor unit 4 when the movable device 2 is in the second position.

[0030] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of symbols]

[0031] In the drawing, 1 is the sensor system, 4 is the sensor unit, 7 is the PC terminal (data processing unit), 9 is the power receiving unit, 10 is the capacitor (storage unit), 11 is the sensor unit, 13 is the communication unit, and 14 is the power supply unit.

Claims

1. A sensor system (1) utilizing wireless power supply, comprising a sensor unit (4) that moves integrally with a movable device, and a power supply unit (14) that wirelessly supplies power, The movable device moves back and forth between the first and second positions, with one cycle consisting of moving from the first position to the second position, stopping at the second position, moving from the second position to the first position, and stopping at the first position. The aforementioned sensor unit is A power receiving unit (9) that receives power from the power supply unit by facing the power supply unit when the movable device is stopped in the first position, A storage unit (10) that stores the power received by the power receiving unit, A sensor unit (11) uses the power supplied from the storage unit as operating power and acquires high-frequency data corresponding to the movable device at a sampling rate higher than a predetermined value, The system includes a communication unit (13) that transmits the data acquired by the sensor unit to a data processing unit via wireless communication, The sensor unit acquires the data during the period in which the movable device moves from the second position to the first position, based on timing set by a timer that defines the timing at which the movable device begins to move from the second position to the first position, and timing set by a timer that defines the data acquisition time. The communication unit is a sensor system that utilizes wireless power supply to transmit the data to a data processing unit via wireless communication during the period when the movable device moves from the second position to the first position.

2. The sensor system using wireless power supply as described in Claim 1, wherein the sensor is an acceleration sensor that acquires vibration data indicating the vibration characteristics of the movable device while the movable device is in motion.

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