CN102090896A - Method for measuring planta pressure for rehabilitation therapy - Google Patents

Abstract

A plantar pressure measurement method for rehabilitation treatment, using thin film piezoresistive pressure sensors placed on the plantar pressure points in the left and right insoles, the insoles have a three-layer structure, the top and bottom layers are fiber layers, and the film piezoresistive The thin-film piezoresistive pressure sensor is fixed on the bottom layer, and the thin-film piezoresistive pressure sensor is connected and fixed with the top fiber through soft bumps. The thin-film piezoresistive pressure sensor transmits the obtained resistance signal corresponding to the pressure to the left and right insole pressure sensors. The corresponding two signal processing transmitters perform resistance-voltage conversion, filter and output to two corresponding microprocessors for AD conversion respectively, and combine the data collected by the two feet into data packets and send them to the receiver together, and the receiver will The left and right foot data are transmitted to the PC through USB, and the PC is triggered by a timer to read the data, unpack the data packet, and perform signal processing and three-dimensional display through software.

Description

A plantar pressure measurement method for rehabilitation therapy

technical field

The present invention relates to a rehabilitation diagnosis and treatment instrument, in particular to a plantar pressure measurement method for rehabilitation treatment, which is mainly applicable to the disease assessment in the early stage of rehabilitation treatment for patients with weakened or lost walking ability, and provides a basis for formulating rehabilitation training plans, Evaluation of the effect during or after rehabilitation training and early detection of diabetes.

Background technique

Due to changes in the living environment and people's eating habits, the incidence of cardiovascular and cerebrovascular diseases such as stroke (commonly known as apoplexy) is very high. Although the mortality rate of apoplexy has decreased with the improvement of current medical technology, those who survive Among the patients, about 70% still have different degrees of limb motor dysfunction such as hemiplegia, and 30% of them can only be accompanied by wheelchairs in the future, and 25% to 30% of stroke patients will relapse within 5 years. In addition, children with cerebral palsy caused by premature or dystocia account for about 0.5% of the children born. These children with cerebral palsy usually do not have normal walking ability. They are likely to be accompanied by wheelchairs and crutches for life, and may never have the opportunity Like other children, enjoy life and receive education. At the beginning of this century, the research of rehabilitation medicine showed that most patients can still recover their original walking ability after receiving correct rehabilitation training. Now it is only necessary to formulate an effective rehabilitation training plan according to the specific conditions of each patient. The formulation and implementation of this training plan is based on the detection and observation of some characteristics of the individual patient itself, such as the patient's walking gait and the pressure distribution of the sole of the foot.

The traditional gait measuring instrument adopts the arrangement of rigid sensor arrays on the soles of the feet, which requires thousands of pressure sensors, resulting in a large amount of data, resulting in low sampling rate, high price, narrow use area, poor flexibility, and poor comfort; The signal transmission mode between the measuring instrument and the PC display, one is the transmission mode of the physical cable, and the other is to save the data of the patient during the test in the memory. After the test is completed, the PC reads it from the memory again. Take the patient's gait data. The former uses physical cables to restrain the freedom of the patient and seriously interferes with the individual being tested, so the measured data is also inaccurate. Although the latter solves the problem of interference to the patient, it cannot observe the patient's gait in real time. The display can only simply show the waveform curve of the regular gait, which is not conducive to the detailed understanding and analysis of the patient's state by rehabilitation doctors and diagnosticians.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, provide a kind of plantar pressure measurement method that is used for rehabilitation treatment, be used for detecting the distribution of plantar pressure when the patient walks, provide quantitative gait measurement data for the rehabilitation training doctor, Doctors can formulate the most suitable training plan for individual patients based on these measured data, helping them recover to normal walking ability faster.

The present invention adopts the following technical solutions: a plantar pressure measurement method for rehabilitation treatment, pressure sensors are arranged in the left and right insoles of the soles, and it is characterized in that: a thin film piezoresistive pressure sensor is placed in the left and right insoles The plantar pressure point, the insole has a three-layer structure, the top layer and the bottom layer are fiber layers, the thin-film piezoresistive pressure sensor is placed and fixed on the bottom layer, and the thin-film piezoresistive pressure sensor is connected and fixed with the top layer of fibers through soft bumps. The thin-film piezoresistive pressure sensor transmits the obtained resistance signal corresponding to the pressure to the resistance-voltage conversion circuit and filter circuit respectively contained in the two signal processing transmitters corresponding to the left and right insole pressure sensors, and then outputs to the two corresponding microprocessors. The converter performs AD conversion separately, packs the data frame format after AD conversion by the microprocessor of one leg, and sends it to the signal processing transmitter of the other leg in the form of Bluetooth, and combines the data collected by the two legs into a data packet and sends it together To the receiver, the receiver transmits the data of the left and right feet to the PC through USB, and the PC reads the data triggered by a timer, unpacks the data packet, performs signal processing and three-dimensional display through software.

The plantar pressure points in the insole refer to the plantar pressure distribution points when normal people walk and stand, and 10 film piezoresistive pressure sensors corresponding to the plantar pressure distribution points can be installed in the left and right insoles, and the left and right insoles are arranged symmetrically. .

In each of the two signal processing transmitters, three four-op amp LM324AD 20-way sensor signal input arithmetic circuits can be set to realize the conversion of pressure-voltage changes, and then the LM324AD constitutes a second-order low-pass filter to process the signal. After filtering and conditioning, it is sent to the microprocessor STM32F103 in the signal processing transmitter to perform AD conversion on the signal, pre-process the data, pack the Bluetooth transmission data packets and drive the Bluetooth transceiver module to send the data to the receiver, and the receiver sends the data to the receiver through USB. The data is transmitted to the PC, and the PC software uses the software written under the MFC framework combined with a set of NI measurement studio controls provided by National Instruments to perform three-dimensional display, waveform display and storage of the twenty pressure signals of the left and right feet.

Compared with the prior art, the present invention has the following advantages:

1) The present invention abandons the traditional arrangement of rigid sensor arrays, selects representative points on the soles of the feet to arrange sensors, greatly reduces the number of sensors, improves the sampling rate without losing effective data, and improves The reliability of the system is improved, and the cost is also greatly reduced. And because the flexible pressure tactile sensor that is more comfortable for the human body is selected, the entire insole is also flexible, which is convenient and comfortable to use, and the measured data is more realistic.

2) The PC display of the traditional gait measuring instrument simply shows the waveform curve of the gait law, which is unfavorable for rehabilitation doctors and diagnostic doctors to understand the patient's state in detail, while the PC display of the present invention adopts the three-dimensional peak map display and The pressure waveform display presents the pressure of each point of the plantar in front of the doctor in the form of a peak map, so that the rehabilitation doctor can see the pressure distribution of the patient's plantar more intuitively, and it is convenient to observe the patient's walking gait in real time.

3) The signal transmission mode between measurement data and PC display, the present invention adopts wireless bluetooth communication mode, which frees patients from the shackles of traditional physical media such as cables, gives patients "wireless" freedom, and makes the data obtained by doctors more convenient. Real and real-time observation of the distribution of plantar pressure when the patient walks or stands, so that the rehabilitation treatment plan formulated is more in line with the actual situation.

4) Most of the traditional plantar pressure testing systems adopt rigid design, narrow use surface, poor flexibility, and poor comfort. However, the present invention uses a flexible film pressure sensor, which is attached to the inner layer of the commonly used fiber insole. Each sensor is equipped with soft bumps, which not only ensures comfort, but also enhances the sensitivity of the pressure sensor, and the measured data is more realistic.

Description of drawings

Fig. 1 is the overall structural block diagram of the present invention;

Fig. 2 is the three-layer structure schematic diagram of insole of the present invention;

Fig. 3 is the bluetooth module circuit diagram of the present invention;

Fig. 4 is the voltage conversion circuit diagram of piezoresistor of the present invention;

Fig. 5 is a circuit diagram of a second-order active low-pass filter of the present invention;

Fig. 6 is a software flow chart of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation.

As shown in Figures 1 and 2, two insoles each contain ten flexible piezoresistive pressure tactile sensors (one for each of the left and right feet), two signal processing transmitters (I and II) and a receiver. The signal processing transmitter obtains the voltage amplitude corresponding to the plantar pressure by processing the signal obtained by the sensor, and then transmits the data to the receiver through Bluetooth transmission, and the receiver transmits the received data to the PC through USB, and the PC The software realizes the three-dimensional peak map display and waveform display of the pressure of 20 points on the soles of the feet, and stores the pressure data for future reference. The white dots on the left and right insoles are where the resistive pressure tactile sensors fit. In the signal processing transmitter, the pressure signal passes through the resistance-voltage conversion circuit, and after filtering, it is sent to the microprocessor for AD conversion, and then sent via Bluetooth. Wireless transmission adopts Bluetooth 2.0 protocol. After receiving the bluetooth signal, the receiver sends the signal to the PC software via USB for further signal processing and three-dimensional display. Twenty flexible piezoresistive pressure tactile sensors (flexiforce) can be used to attach to the body surface where the plantar pressure of the human body is representative when walking and standing, and ten sensors are respectively distributed on the left and right soles. When a person stands on it or walks wearing the shoes equipped with the present invention, these sensors can collect the corresponding pressure signals of each part of the sole, and the front end thereof is reflected in the change of the resistance value of the sensor. Then, the inverse proportional operation circuit composed of the sensor and the operational amplifier converts the change of resistance corresponding to the plantar pressure into a corresponding voltage change. The change of the voltage amplitude is proportional to the change of the plantar pressure, that is, the greater the amplitude of the voltage signal, the greater the plantar pressure. Pass the twenty-way voltage signals of the left and right feet through the second-order Butterworth low-pass active filter, and the cut-off frequency is 16HZ. Then input the filtered signal to the AD conversion input terminal of the microprocessor STM32F103, and the microprocessor STM32F103 performs scanning 12BitAD conversion on these voltage signals, converts the analog signal of the voltage into a digital signal, and then converts the digital quantity to Wireless transmission to PC. The PC is written under the framework of MFC combined with a set of controls (NI measurement studio) provided by National Instruments. It can perform three-dimensional display, waveform display and storage of 20 channels of pressure signals from the left and right feet, and the interface is simple and intuitive. The shape of the instrument is similar to that of an insole, and it uses a flexible pressure tactile sensor. Therefore, the entire insole is also flexible, and the user can put it into the shoes used in daily life for convenient and comfortable use. During the user's walking process, the invention can measure the distribution of the plantar pressure. The measured plantar pressure data is transmitted to the PC in the form of wireless bluetooth for analysis by doctors. The way of wireless transmission allows users to get rid of the shackles of physical media such as cables, so the measured data is more real. Fig. 2 is a schematic diagram of the three-layer structure of the insole of the present invention. Both the top and bottom layers of the insole are fiber layers. The thin-film pressure sensor is placed close to the bottom layer, and the sensor is connected to the top layer of fibers through soft bumps, so that the measurement effect of the plantar pressure is more obvious.

Referring to Fig. 3-5, the hardware circuits adopted in the present invention are all known circuits. The conversion from pressure change to voltage change of the piezoresistive pressure sensor is realized by an arithmetic circuit with six pieces (three pieces for each of the left and right pins) and twenty-way sensor signal input of four operational amplifiers LM324AD. Then LM324AD constitutes a second-order low-pass filter with a cutoff frequency of 16Hz to filter and condition the signal. The microprocessor STM32F103 is responsible for AD conversion of the signal, data preprocessing, packaging of Bluetooth transmission data packets and driving the Bluetooth module to send the data to the PC. The system is powered by a common lithium battery, and the power supply voltage required by each circuit module is obtained through circuits such as boost, step-down, and voltage regulation. The user slave sends data to the receiver through the Bluetooth 2.0 protocol, and the receiver sends the signal to the PC for display through USB.

Fig. 6 is a working flow diagram of the software of the PC and the signal processing transmitter. As shown in the figure, the pressure signal of the corresponding point collected by the sensor on one insole is converted by the microprocessor AD in the signal processing transmitter II, then packed in a certain data frame format, and then sent to the other in the form of Bluetooth. The signal processing transmitter 1 corresponding to the insole, and the data gathered by the sensor of the corresponding insole of the transmitter 1 are combined into a data packet with a certain format and sent to the receiver together, and then the receiver transmits the left and right foot data to the PC through USB. The PC reads data triggered by a timer, unpacks the data packet, saves it after obtaining valid data, and refreshes the interface display. .

Claims (3)

1. A plantar pressure measuring method for rehabilitation therapy, a pressure sensor is arranged in the left and right insoles of the sole, it is characterized in that: the plantar pressure points that adopt the film piezoresistive pressure sensor to be placed in the left and right two insoles, The insole has a three-layer structure. The top and bottom layers are fiber layers. The piezoresistive thin-film pressure sensor is placed and fixed on the bottom layer. The sensor transmits the obtained resistance signal corresponding to the pressure to the resistance-voltage conversion circuit and filter circuit included in the two signal processing transmitters corresponding to the left and right insole pressure sensors, and then outputs to the two corresponding microprocessors for AD conversion respectively. , pack the data frame format after AD conversion by the microprocessor of any foot, send it to the signal processing transmitter of the other foot in the form of bluetooth, combine the data collected by the two feet into a data packet and send it to the receiver together, and receive The device transmits the data of the left and right feet to the PC through USB, and the PC reads the data triggered by a timer, unpacks the data packet, performs signal processing and three-dimensional display through software. 2. the plantar pressure measuring method that is used for rehabilitation treatment according to claim 1, is characterized in that: the plantar pressure point system in said shoe-pad is with reference to the plantar pressure distribution point when normal person walks and stands, left and right shoe-pads There are 10 thin-film piezoresistive pressure sensors corresponding to the pressure distribution points on the soles of the feet, and the left and right insoles are arranged symmetrically. 3. the plantar pressure measurement method that is used for rehabilitation treatment according to claim 1 or 2, is characterized in that: in two signal processing transmitters, respectively arrange 20 road sensor signal inputs of 3 four operational amplifiers LM324AD The arithmetic circuit realizes the conversion of pressure-voltage change, and then the second-order low-pass filter is formed by LM324AD, and the signal is filtered and conditioned, and then sent to the microprocessor STM32F103 in the signal processing transmitter to perform AD conversion on the signal and pre-prediction of the data Processing, packaging of Bluetooth transmission data packets and driving the Bluetooth transceiver module to send the data to the receiver, the receiver transmits the data to the PC through USB, and the PC software uses the NI measurement studio provided by the National Instruments under the MFC framework. The software written by the control group can perform three-dimensional display, waveform display and storage of the twenty pressure signals of the left and right feet.

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