JP7845154B2 - Sensor system using wireless power transfer - Google Patents

Description

This invention relates to a sensor system utilizing wireless power transfer.

Traditionally, production equipment has faced challenges such as abnormal shutdowns and malfunctions due to wear and tear or damage to moving parts, resulting in decreased productivity. To address this issue, a diagnostic technology has been developed that involves installing acceleration sensors that detect high-frequency vibrations (e.g., 20 kHz or higher) on moving parts. This technology acquires high-frequency data indicating the vibration characteristics of the moving parts from the acceleration sensors to understand the state of the production equipment. Acceleration sensors used to detect vibrations in moving parts include small wired sensors or large wireless sensors equipped with rechargeable batteries.

Wired sensors have the risk of wire breakage, and to avoid this, their installation location, operating speed, and range of motion are limited. Furthermore, replacing the sensor requires rerouting the wiring. On the other hand, wireless sensors require battery replacement and charging, limiting their installation location to a position where the battery can be easily removed. They also have the challenge of not being able to acquire data at a high sampling rate, making it difficult to properly acquire high-frequency data. 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 power is wirelessly supplied from an external power supply unit to the power receiving unit.

Japanese Patent Publication No. 2022-53125

Patent Document 1 describes a method for wirelessly powering a wireless sensor, which eliminates the problems associated with wiring for wired sensors, while also eliminating the need for battery replacement and charging. This resolves the issues of workability and installation flexibility associated with batteries. However, Patent Document 1 does not anticipate the acquisition of high-frequency data at a high sampling rate, and therefore the problem of not being able to properly acquire high-frequency data remains unresolved.

This invention was made in view of the above circumstances, and its purpose is to provide a sensor system utilizing wireless power transfer that improves workability and flexibility in installation location, while also enabling the appropriate acquisition of high-frequency band data.

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 a first position to a second position, stopping at the second position, moving from the second position to the first position, and stopping at the first position. The sensor unit comprises 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 at the first position , 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.

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, the high-frequency data can be acquired appropriately.

Diagram illustrating the configuration of one embodiment of the present invention. Functional block diagram Timing chart

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.

The movable device 2 moves back and forth in a linear fashion, with one cycle consisting of movement from the first position to the second position, stopping at the second position, movement from the second position to the first position, and stopping at the first position. Movement from the first position to the second position, i.e., movement in the direction of arrow A1, is called forward movement, and movement from the second position to the first position, i.e., 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 linearly as a single unit.

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 conform to, 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.

The sensor unit 4 and the power supply unit 5 are identical in size; for example, their dimensions are 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. Figure 1 exaggerates the distance between them for illustrative purposes, and the ratio of the sizes of the sensor unit 4 and power supply unit 5 to the distance between them differs 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.

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.

The power supply unit 14 wirelessly supplies power from an external source to the power receiving unit 9. The power receiving unit 9 receives the 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.

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

The sensor unit 11 includes an acceleration sensor and is positioned to detect vibrations generated by the reciprocating linear movement of the movable device 2. The sensor unit 11 operates using power supplied from the capacitor 10 as its operating power. Upon receiving a data acquisition start command from the CPU 8, it begins data acquisition, acquiring high-frequency vibration data representing the vibration characteristics of the movable device 2 at a sampling rate higher than a predetermined value, and outputs the acquired high-frequency vibration data to the memory 12. The sensor unit 11 terminates its data acquisition operation upon receiving a data acquisition end command from the CPU 8. The predetermined value can be determined, for example, according to the quality assurance specifications required for the sensor system 1.

The memory 12 operates using power supplied from the capacitor 10 as its operating power. When it receives a data retention command as a control command from the CPU 8, it receives high-frequency vibration data from the sensor unit 11 and temporarily holds that input high-frequency vibration data.

The communication unit 13 operates using power supplied from the capacitor 10 as its operating power. Upon receiving a data transmission command as a control command from the CPU 8, it reads high-frequency vibration data temporarily stored in the memory 12 and transmits the read high-frequency vibration data to the PC terminal 7 via wireless communication. The wireless communication method is, for example, a short-range wireless communication standard such as Bluetooth® or Bluetooth Low Energy.

Next, the operation of the above configuration will be explained with reference to Figure 3.
The movable device 2 moves back and forth in a linear fashion, with one cycle consisting of moving forward from time t1 to time t2, stopping at the second position from time t2 to time t3, moving backward from time t3 to time t7, and stopping at the first position from time t7 to time t8.

The CPU 8 has a first timer that measures the waiting time from the start of the movable device 2's forward movement to the start of its backward movement, i.e., the time until vibration data acquisition begins, and a second timer that measures the vibration data acquisition time. The vibration data acquisition time is a time that can be arbitrarily specified within the time from the start to the end of the movable device 2's backward movement. The CPU 8 starts timing the first timer at the start of the movable device 2's forward movement (t1). When the timing of the first timer is completed, i.e., at the start of the movable device 2's backward movement, the CPU 8 outputs a data acquisition start command to the sensor unit 11 and starts timing the second timer. The CPU 8 also outputs a data transmission command to the communication unit 13.

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

When the second timer expires, the CPU 8 outputs a data acquisition termination command to the sensor unit 11. Upon receiving the data acquisition termination command from the CPU 8, the sensor unit 11 terminates the acquisition of high-frequency vibration data (t5). When the communication unit 13 has read all the high-frequency vibration data stored in the memory 12, it terminates the transmission of the high-frequency vibration data to the PC terminal 7 (t6). The PC terminal 7 can analyze the high-frequency vibration data received from the sensor unit 4 to diagnose wear, damage, etc., to the movable equipment 2.

When the movable device 2 finishes its retraction 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.

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 device 2 at a sampling rate higher than a predetermined value, conventional battery replacement and charging work is eliminated, resolving issues related to battery-related workability and flexibility of installation location. 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 appropriately acquired.

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 directly.

This disclosure is described in accordance with the embodiments, but is not limited to those embodiments or structures. This disclosure also encompasses various modifications and variations within the equivalence range. Furthermore, 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.

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 indicating the vibration characteristics of movable equipment was used. 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.

While the example illustrates 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, the power supply unit 5 may also be positioned at the location facing the sensor unit 4 when the movable device 2 is in the second position, thereby enabling power to be supplied from the power supply unit 14 to the power receiving unit 9 when the movable device 2 is stopped in the second position. Furthermore, the power supply unit 5 may be positioned at two locations: the location facing the sensor unit 4 when the movable device 2 is in the first position and the location facing the sensor unit 4 when the movable device 2 is in the second position, thereby enabling power to be supplied from the power supply unit 14 to the power receiving unit 9 in both the first and second positions.

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 using 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 composed of 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.

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 (2)

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 . 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 .