TW201346238A - Wireless plantar pressure sensor system - Google Patents

Abstract

A wireless plantar pressure sensor system comprises at least a pressure sensing unit set on a soft substrate, a signal processing module, a wireless communication module, and a computer or mobile phone; the wireless communication module can transmit the measured pressure signals from the sensing units to the computer or the mobile phone for displaying and further applications. A user worn the shoes with the wireless plantar pressure sensor substrate can monitor the center of pressure for each foot while moving directly through the mobile phone. By sending the measured data to the cloud and through computing based on rule base, the user can obtain more information about his gait analysis, and whether he needs an orthotic insole for adjusting his gait.

Description

Wireless foot pressure sensing system

The invention relates to a device for measuring the change of the pressure of the sole of the foot in combination with the pressure sensing unit, in particular to mean that the plurality of capacitive pressure sensing units are evenly distributed on a flexible substrate, and the scanning is performed by a low-power microprocessor system. The pressure sensing unit and Bluetooth low-power transmission to the mobile phone/cloud, to achieve the purpose of monitoring the pressure change of the foot.

At present, research or products for plantar pressure sensing have increased significantly compared to the past. The earliest previous foot pressure measurement system was a kind of rubber cone material and lattice structure mat. The ink was squeezed out between the sole and the mat to quantify the pressure into a positive force value. In the past two decades, with the development of sensor technology and the popularity of processors, measurement systems have been developed to date. The most common and main methods for measuring dynamic foot pressure during walking are: 1. Force Plate The System is a pressure platform type system with higher resolution than the Placed Sensors System system, but at a higher price. 2. Placed Sensors System puts the sensor on the sole of the foot or in the shoe to measure the sole of the foot. The price is relatively low and it is easy to accept.

Other companies also use capacitive sensors or self-developed sensors to make force-measuring shoes and force-test insoles, which are representative of the following: 1. Pennsylvania State University (The A pressure gauge insole developed by Pennsylvania State University in the early 1980s that uses a high-precision pressure inductive meter to measure the distribution of pressure. 2. In 1990, Tekscan developed a F-Scan insole system. 3. Germany Novel Company developed the Emed force plate system and Pedar force insole system based on the capacitance measurement theory. 4. The Parotec-system system developed by Kraemer, Germany, is a wireless measurement system, and its subjects are free from the transmission line and processor. None of the above products are combined with smart phones, especially the Bluetooth 4.0 communication method, so that the mobile phone screen instantly displays the change of foot pressure and transmits it to the cloud for recording and calculation; in addition, the above-mentioned products cannot use only buttons. The battery has been used for at least ten hours or longer; the price is quite high, generally ranging from tens of thousands to hundreds of thousands of yuan, and the fatigue resistance has to reach hundreds of thousands of times - millions of walking steps, not More common.

It can be seen that there are still many shortcomings in the above-mentioned methods of use, which is not a designer who is good and convenient to use, and needs to be improved.

The invention provides a device for measuring the pressure change of the sole of the foot in combination with the pressure sensing device, in particular, the plurality of capacitive pressure sensing units are evenly distributed on a flexible substrate, and then the force measuring substrate is placed into a shoe. Under the insole, the user wears the shoe activity, scans the pressure sensing units by a low-power microprocessor system, and transmits the Bluetooth low energy to the mobile phone/cloud to monitor the pressure change of the sole.

The invention designs the plantar pressure sensing device on a flexible substrate, and then places the force measuring substrate under the insole of a shoe, and selects low-power parts during circuit planning to achieve low power consumption. The purpose is to supply power to a small-capacity battery for at least ten hours of continuous operation.

The invention designs the plantar pressure sensing device on a flexible substrate, and then places the force measuring substrate under the insole of a shoe, in order to reduce the weight, to avoid increasing the weight of the shoe, the signal processing circuit and the Bluetooth transmission. The modules are mainly made up of small surface mount components (SMD), which can make the foot pressure sensing system compact and lightweight.

The invention designs the plantar pressure sensing device on a flexible substrate, and then places the force measuring substrate under the insole of a shoe, and fuses the force measuring substrate on the appearance of the shoe, the signal processing circuit and the blue bud The transmission module is mainly made up of small surface-adhesive components (SMD), and the design of the force-measuring substrate also enables the foot-pressure sensing system to achieve miniaturization and concealment.

As shown in FIG. 1 , the sole pressure sensing device 100 of the present invention includes at least one pressure sensing unit 3, a flexible substrate 2 on which the pressure sensing units 3 can be disposed, a transmission line 4, and a signal processing module. The group and the wireless communication module 1; the plurality of pressure sensing units 3 are distributed in an array on the flexible substrate 2, and the pressure sensing unit 3 is composed of a flexible dielectric material covering the conductive film as an electrode, when pressure is applied In the pressure sensing unit 3, the capacitance value is changed by the deformation of the soft dielectric material, and the upper and lower electrodes of the pressure sensing unit 3 distributed in the array manner are connected in series or in parallel to form a row and a column of wiring, via the transmission line. 4 is connected to the connector 110 of the signal processing module 1; as shown in FIG. 2, the signal processing module and the wireless communication module 1 include a scanning integrated circuit 101 and 102, a capacitor amplifying integrated circuit 103, and a microcontroller. With a wireless communication module 104 and a battery 105; the above electronic components basically have to select a low power consumption specification. The preferred choice of the wireless communication module is Bluetooth Low Energy (BLE). If the size is reduced, the microcontroller and the wireless communication module can preferably use Texas Instruments TI CC2540/2541. Two-in-one system chip (SOC). The scan integrated circuit is used to sequentially select a row of the pressure sensing unit 3 in a row to connect the capacitor amplifying integrated circuit, convert the changed capacitance value of the pressure sensing unit 3 into a voltage signal and amplify, and then The amplified voltage signal enters the analog digital converter (ADC) of the microcontroller and is converted into a digital signal. The digital signal is converted into a pressure signal by the operation of the microcontroller, and then transmitted to the outside through the wireless communication module. As shown in FIG. 1 and FIG. 4, the design of the transmission line 4 has a specific meander shape, and the purpose is that when the flexible substrate 2 of the pressure sensing unit 3 is placed under the insole of the shoe, the signal processing module can be just wirelessly communicated. The module 1 can be placed under the label or pocket of the free end of the tongue so that the appearance of the shoe does not reveal the presence of the force measuring substrate. This design allows the foot pressure sensing system to achieve miniaturization and concealment.

As shown in FIG. 3, which is a preferred use example of the plantar pressure sensing device 100 of the present invention, the plantar pressure sensing device 100 of FIG. 1 senses the plantar pressure distribution of the plurality of pressure sensing units 3 thereof. The value is transmitted to the external mobile phone 6 or computer 7 through the wireless communication module. It is particularly worth mentioning that the microcontroller is responsible for analyzing and converting the signals of each pressure sensing unit 3. Since the capacitance characteristics generated by each pressure sensing unit 3 are inconsistent, the initial values of the capacitances of each pressure sensing unit are different. The relationship between the amount of pressure and the change of the capacitance value is not the same for each pressure sensing unit. Therefore, it is necessary to establish a database or a comparison table to adapt to each pressure sensing unit, and through the calibration procedure of the microcontroller, to correctly obtain each The initial value of the pressure sensing unit and its change in pressure and capacitance values. It should be particularly emphasized that in order to allow a small-sized battery such as a button battery to be continuously used for a long period of time, the wireless communication module uses a Bluetooth 4.0 low-power module, and the mobile phone must also support Bluetooth 4.0 communication functions, such as the iPhone 4S, or It is a smart phone and tablet that supports Android 4.0, or a laptop or plug-in transmitter (Dongle) that supports Bluetooth 4.0.

Further, the signal processing module and the wireless communication module 1 are wirelessly transmitted to the data of the computer 7 or the mobile phone 6 for analysis, for example, when the user walks, the feet are stepped on the pressure sensing devices at various points, so that the pressure sensing at each point is performed. The unit pressure changes, the computer 7 or mobile phone 6 program can calculate the body weight and center of gravity or Center of Pressure (COP), especially the position of the COP with the gait, and then via the computer 7 or the phone 6 WIFI Or the 3G function is transmitted to the cloud, and the rule base is used to evaluate the bad walking posture of the user's foot to facilitate the production of the foot accessory such as the insole or the air cushion deformation mechanism, thereby improving the damage caused by the user's bad traveling posture.

As shown in FIG. 1 and FIG. 3, the sole pressure sensing device 100 includes at least one pressure sensing unit 3, a flexible substrate 2 for arranging the pressure sensing units 3, a transmission line 4, and a signal processing module. And the wireless communication module 1; the plurality of pressure sensing units 3 are distributed in an array on the flexible substrate 2, and the pressure sensing unit 3 is composed of a soft dielectric material covering the conductive film as an electrode, when pressure is applied The pressure sensing unit 3 has a capacitance value that changes due to deformation of the soft dielectric material. 1 shows a total of 16 pressure sensing units 3, 8 in the sole portion and 8 in the heel portion. This is not a necessary limitation. Less pressure sensing unit can reduce the cost, and more pressure sensing units can be used. More accurate and higher resolution to obtain the pressure distribution of the sole. The soft dielectric material of each of the pressure sensing units may have a thickness of between 0.1 mm and 1 mm and an area of between 1 mm ^{2 and} 400 mm ² , depending on the application.

The main procedures used in the present invention are as follows:

Step 1: When the system is started, the user wears the shoes 8 of the built-in sole pressure sensing device 100 and walks. When the sole contacts the ground, the sensing unit in the sensing device 100 receives different pressures and immediately passes the signal processing. The module and the wireless communication module 1 process the correction to send the actual foot pressure value to the computer 7 or the mobile phone 6.

Step 2: When the computer 7 or the mobile phone 6 receives the pressure data transmitted by the wireless communication module, the data analysis and display can be performed. The display part can see the distribution of the power and the COP position, and the analysis part can first store the pressure data in the memory. In the body, when the analysis is needed, the data is transmitted to the cloud server for analysis, and the analysis result is displayed on the computer 7 or the mobile phone 6 screen.

As shown in FIG. 3 and FIG. 4, the user wears the shoe 8 with the plantar pressure sensing device 100 to walk and hop, and the system of foot pressure sensing combined with wireless communication can instantly sense the distribution of the plantar pressure. The situation and the position of the center of gravity of the sole are displayed on the computer 7 or the mobile phone 6, and a piece of data can also be stored and uploaded to the cloud server for analysis. As shown in FIG. 5, the color change 11 corresponding to the pressure magnitude of each pressure sensing unit, the center of gravity of the plantar pressure distribution, and the message frame 9 can be displayed on the screen. Message box 9 can have current weight information, or the size of the overall foot force, and the analysis results returned from the cloud server. If the size of the overall foot force exceeds the excessive weight, it may mean that the user walks heavily, and the mood is not good.

As shown in FIG. 2, at least one three-axis accelerometer 106 is further added to the signal processing module 1 for detecting the trajectory of the foot motion. Further, at least one multi-axis gyroscope 107 is further mounted on the signal processing module 1 for detecting the steering of the foot motion. Further, in the cloud, the force of the ground landing is changed, and the trajectory and movement of the foot before the foot is not touched are integrated to obtain the correctness of the whole process of the foot movement and the correctness of the posture, which is conducive to correction or rehabilitation.

Embodiment 1

Figure 6 shows the signal flow of the system as a whole. The plantar pressure sensing device 100 is placed at the bottom of the insole at a scanning speed of 10 times per second. The regulated power supply circuit 12 provides a stable voltage source to the Bluetooth 4.0 module 13 and the signal processing module 15. The user walks on the shoe with the array-type foot pressure sensing substrate 14. When the sole touches the ground, the sensing unit in the sensing device receives different pressures, and the scanning and amplifying circuits of the signal processing module 15 are different. DC voltage. The microcontroller of the signal processing module 15 converts the DC voltage analog signal into digital signal data and stores it in the Bluetooth 4.0 module 13. The Bluetooth 4.0 module 13 is transmitted to the mobile phone 18 by wireless transmission, or transmitted to the Bluetooth 4.0 external transmission transmitter (Dongle) 16 and transmitted to the computer 17 via USB. Each time the mobile phone 18 or the computer 17 receives the information, each sensing unit is displayed on the foot position corresponding to the mobile phone program, and the color of the upper color changes from shallow to deep depending on the force, the mobile phone 18 or The color displayed by the computer 17 is the current state of the user's current plantar pressure, and the pressure information is stored and displayed in the mobile phone 18 or the computer 17 each time. In addition, the application will use the value and position of the current 16 sensing units to calculate the user's center of gravity, and present it in the form of a red dot at the sole of the foot, thereby observing the movement trajectory of the user's center of gravity. During the measurement, the mobile phone 18 or the computer 17 will temporarily store all the data in the memory, and after the measurement is finished, it can be uploaded to the cloud 19, and the information can be used to analyze the state of the user walking, and the cloud 19 analyzes The finished result will be displayed back on the mobile phone 18 or the computer 17.

In summary, the system of plantar pressure sensing combined with wireless communication is only based on the human foot, but not limited to this, the foot pressure sensing system can be made into a cushion or a back pad or a robot or The force sensor of the prosthetic force transmits the force distribution of the hip or the back or the robot or the prosthetic to the object in an instant wireless manner.

Although the present invention has been described above in terms of a preferred embodiment, it is not intended to limit the invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

1. . . Signal processing module and wireless communication module

2. . . Setting a flexible substrate of the pressure sensing unit

3. . . Pressure sensing unit

4. . . Transmission line

5. . . Foot

6. . . Mobile phone

7. . . computer

8. . . Shoes with plantar pressure sensing device

9. . . Message box

10. . . Center of gravity of the plantar pressure distribution

11. . . The color change corresponding to the pressure

12. . . Regulated power supply circuit

13. . . Bluetooth 4.0 module

14. . . Array type plantar pressure sensing substrate

15. . . Signal processing module

16. . . Bluetooth 4.0 Extrapolation Transmitter (Dongle)

17. . . computer

18. . . Mobile phone

19. . . Cloud

100. . . Plantar pressure sensing device

110. . . Connector

101. . . Scan integrated circuit

102. . . Scan integrated circuit

103. . . Capacitance amplification integrated circuit

104. . . Microcontroller and wireless communication module SOC

105. . . battery

106. . . Three-axis accelerometer

107. . . Multi-axis gyroscope

1 is a schematic diagram of a sole pressure sensing device of the present invention, comprising a plurality of pressure sensing units and a signal processing module.

2 is a schematic diagram of the measurement application of the present invention by measuring the pressure of the foot through a wireless transmission module and transmitting it to a computer or a mobile phone.

Figure 3 is a schematic view of a user of the present invention wearing a shoe having a plantar pressure sensing device.

Figure 4 is a schematic view showing the distribution of the pressure and center of gravity of the foot of the present invention.

FIG. 5 is a block diagram showing the internal circuit of the signal processing module of the present invention.

Figure 6 shows an embodiment of use of the present invention

1. . . Microprocessor system and line transmission module

2. . . Setting a flexible substrate of the pressure sensing unit

3. . . Pressure sensing unit

4. . . Transmission line

5. . . Foot

6. . . Mobile phone

7. . . computer

9. . . Message box

Claims (10)

A wireless foot pressure sensing system includes: a sole pressure sensing device comprising a flexible substrate, at least one capacitive pressure sensing unit disposed on the flexible substrate for obtaining foot pressure information, a signal processing module, The pressure sensing unit is electrically coupled to the pressure sensing unit, and the processing signals of the pressure sensing units are processed, and a wireless communication module and an electrical connection signal processing module are sent from the signal processing module. The group of processed plantar pressure signals are wirelessly transmitted to the outside, a battery for supplying power to the electronic components, and a computer or a mobile device for receiving and analyzing the plantar pressure signals from the wireless communication module. The wireless foot pressure sensing system of claim 1, wherein the signal processing module mainly comprises a scanning integrated circuit, a capacitor amplifying integrated circuit, and a microcontroller; and the scanning integrated circuit is used. The pressure sensing unit of a certain row is selected in sequence to be coupled to the capacitor amplification integrated circuit, the capacitance value of the pressure sensing unit is converted into a voltage signal and amplified, and then the amplified voltage signal enters the microcontroller. The analog digital converter (ADC) is converted into a digital signal, and the digital signal is converted into a pressure signal by a microcontroller operation. The wireless foot pressure sensing system of claim 1, wherein the wireless communication module is a module that complies with Bluetooth 4.0 and above. The wireless foot pressure sensing system according to claim 2, wherein the microcontroller mainly performs different pressure and capacitance value change characteristics for each pressure sensing unit by establishing a database for each pressure sense. The calibration of the measurement unit causes each pressure sensing unit to output the correct pressure signal. The wireless foot pressure sensing system according to claim 1, wherein the user further wears a shoe with a foot pressure sensing device on both feet, and steps on each pressure sensing unit while walking, so that each pressure is applied. The sensing unit generates a pressure signal change, calculates the body weight and the center of gravity position, and then transmits the data to the computer or the mobile phone through the wireless communication module and then sends the data to the cloud, and uses the rule base to evaluate the bad walking posture of the user's foot to benefit the foot. The auxiliary equipment such as the insole or the air cushion deformation mechanism is manufactured to improve the user's injury caused by the bad traveling posture. For example, the wireless foot pressure sensing system of claim 1 further includes at least one three-axis accelerometer in the signal processing module for detecting the trajectory of the foot movement. The wireless foot pressure sensing system according to claim 1, further comprising at least one multi-axis gyroscope in the signal processing module for detecting the steering of the foot motion. For example, the system described in claim 5-7 further integrates the force of the foot landing in the cloud, and the movement track and movement steering before the foot is not touched to obtain the coordination of the whole process of the foot movement. The correctness of sex and posture is conducive to correction or rehabilitation. The wireless foot pressure sensing system according to claim 1, wherein the flexible substrate and the transmission line are designed to have a specific meander shape, and the purpose is that the soft substrate can be just placed under the insole of the shoe. The processing module and the wireless communication module can be placed under the label or pocket of the free end of the tongue so that the appearance of the shoe does not have the presence of a foot pressure sensing device. The wireless foot pressure sensing system according to claim 1, wherein the computer or the mobile device supports the communication function of the Bluetooth 4.0 and above specifications.