Acupuncture point positioning and electric pulse regulation and control device and method based on electrical impedance feedback

Abstract

The invention provides an acupoint positioning and electric pulse regulation and control device and method based on electrical impedance feedback, and the device comprises a bioelectrical impedance detection module which is provided with a flexible wearing hardware part, and the flexible wearing hardware part is provided with an electrode for collecting a skin electrical impedance signal, the bioelectrical impedance detection module determines a target acupuncture point area for placing an electrode according to the electrical impedance signal; the initial pulse output module is used for outputting a preset initial electric pulse signal to an electrode of the flexible wearing hardware part; the dynamic cooperative control module is used for adjusting an electric pulse parameter according to a real-time skin electrical impedance signal acquired by the electrode after the initial electric pulse signal is applied to the target acupuncture point area through the electrode; the electric pulse output module outputs electric pulse signals to an electrode according to the adjusted electric pulse parameters, acupuncture points can be accurately positioned, the electric pulse output parameters can be accurately adjusted, stimulation output is dynamically optimized through a feedback mechanism under the condition that the skin state of a patient changes or the characteristics of the acupuncture points are different, and the treatment effect and the comfort of the patient are improved.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to an acupoint positioning and electric pulse regulation device and method based on electrical impedance feedback. Background Art

[0002] Chronic pain is a common health problem that seriously affects the quality of life. There are various treatment methods, including medication, physical therapy, and traditional Chinese medicine acupuncture. However, existing treatment methods have many limitations. Although medication is effective quickly, long-term use can easily lead to dependence or adverse reactions; although traditional Chinese medicine acupuncture has significant efficacy, its invasiveness and operational complexity limit its popularization and application; physical therapy equipment is cumbersome to operate and its efficacy depends on the individual compliance of patients. In recent years, non-invasive transcutaneous electrical nerve stimulation (TENS) technology has received widespread attention due to its convenience and non-invasiveness. However, current TENS devices have technical and usage deficiencies.

[0003] Existing TENS devices rely on manual experience or fixed electrode arrangements for acupoint positioning, which makes it difficult to achieve real-time and accurate acupoint identification, thus affecting the treatment effect. Secondly, the output electrical pulse parameters are usually fixed settings, lacking dynamic adjustment for individual differences of patients, and cannot fully adapt to the skin characteristics and treatment needs of different patients, resulting in fluctuations in efficacy. In addition, the wearing comfort of existing equipment is poor, the electrode material is prone to cause skin discomfort, and long-term use may cause irritation or allergic reactions at the contact site. Summary of the invention

[0004] The present invention is made to solve the above-mentioned problems, and its purpose is to provide an acupoint positioning and electric pulse regulation device and method based on electrical impedance feedback.

[0005] The present invention provides an acupoint positioning and electric pulse regulation device based on impedance feedback, which has the following characteristics, including: a bioimpedance detection module, which has a flexible wearable hardware part, the flexible wearable hardware part has electrodes for collecting skin impedance signals, and the bioimpedance detection module is used to determine the target acupoint area where the electrodes are placed according to the impedance signals; an initial pulse output module, which is used to output a predetermined initial electric pulse signal to the electrodes of the flexible wearable hardware part; a dynamic collaborative control module, which is used to adjust the electric pulse output parameters according to the real-time skin impedance signal collected by the electrodes after the initial electric pulse signal is applied to the target acupoint area through the electrodes; an electric pulse output module, which is used to output the electric pulse signal to the electrodes of the flexible wearable hardware part according to the adjusted electric pulse output parameters, wherein the dynamic collaborative control module obtains the real-time skin impedance according to the real-time skin impedance signal, and when the change value of the real-time skin impedance within a predetermined time interval is greater than a preset impedance change value threshold, the electric pulse output parameters are adjusted based on the feedback adjustment formula and the impedance change value.

[0006] In the acupoint positioning and electric pulse regulation device based on impedance feedback provided by the present invention, it can also have the following characteristics: wherein, the bioimpedance detection module also includes: a denoising unit for denoising the impedance signal; a classification and identification unit for extracting key features of the impedance signal using the frequency response characteristics, and classifying the key features to identify the target acupoint area, key features, including amplitude changes and frequency dependence of the low impedance area.

[0007] The acupoint positioning and electric pulse regulation device based on electrical impedance feedback provided by the present invention may also have the following features: wherein the bioelectrical impedance detection module supports multi-frequency impedance measurement with a frequency range of 10kHz to 100kHz, and combines the following formula to achieve accurate identification of low impedance areas:

[0008]

[0009] Where R adj is the adjusted impedance value, f is the measurement frequency, C is the equivalent capacitance, d is the contact thickness between the skin and the electrode, α is the impedance characteristic attenuation coefficient, R meas is the collected impedance value.

[0010] In the acupoint positioning and electric pulse regulation device based on impedance feedback provided by the present invention, it can also have the following characteristics: wherein, the initial pulse output module includes: an initial pulse parameter selection unit, which is used to select the electric pulse amplitude and electric pulse frequency according to the target acupoint area, and calculate the current flowing through the skin; an initial treatment time selection unit, which is used to select the treatment time; an output unit, which is used to output an electric pulse signal of a preset duration to the electrodes of the flexible wearable hardware part according to the electric pulse amplitude, frequency and the current flowing through the skin.

[0011] In the acupoint positioning and electric pulse regulation device based on electrical impedance feedback provided by the present invention, it can also have such a feature: wherein the dynamic collaborative control module is used to adjust the electric pulse output parameters based on the feedback adjustment formula and the impedance change value after the preset duration of the output electric pulse signal, when the change value of the real-time skin impedance is greater than the preset impedance change value threshold, wherein the feedback adjustment formula is as follows:

[0012] P(t)=P 0 +k·(R Ref -R t )

[0013] Where P(t) is the current power, P 0 is the basic power, R t is the real-time impedance value, R Ref is the reference impedance value, k is the adjustment coefficient, R Ref -R tis the impedance change value, wherein the adjusted electrical pulse signal output parameters include frequency, amplitude and pulse width.

[0014] In the acupoint positioning and electric pulse regulation device based on impedance feedback provided by the present invention, it can also have the following features: a parameter optimization module is used to obtain patient response feedback and update the electric pulse output parameters according to the patient response feedback and the parameter optimization formula; the electric pulse output module is also used to output the electric pulse signal according to the electric pulse output parameters updated by the parameter optimization module.

[0015] The acupoint positioning and electric pulse control device based on electrical impedance feedback provided by the present invention may also have the following features: wherein the parameter optimization formula is as follows:

[0016]

[0017] Where T opt is the output parameter of the electric pulse signal, y i is the patient response feedback, f(x i ,T) is the parameter model output, λ||T|| 2 is the regularization term.

[0018] In the acupoint positioning and electric pulse regulation device based on impedance feedback provided by the present invention, it can also have the following features: a skin condition monitoring module is used to detect the current humidity, temperature and contact quality of the skin to optimize the electric pulse output parameters, and the dynamic collaborative control module is also used to adjust the electric pulse output parameters according to the current humidity, temperature and contact quality of the skin.

[0019] The acupoint positioning and electric pulse regulation device based on electrical impedance feedback provided by the present invention may also have the following features: a power management module for real-time monitoring of power and issuing an alarm when the device is low on power.

[0020] The present invention provides an acupuncture point positioning and electric pulse control method based on electrical impedance feedback, which may also have the following features: determining the target acupuncture point area for placing electrodes according to the electrical impedance signal;

[0021] Outputting a predetermined initial electrical pulse signal to the electrodes of the flexible wearable hardware portion;

[0022] After the initial electrical pulse signal is applied to the target acupuncture point area through the electrode, the electrical pulse output parameters are adjusted according to the real-time skin electrical impedance signal collected by the electrode;

[0023] According to the adjusted electrical pulse output parameters, electrical pulse signals are output to the electrodes of the flexible wearable hardware part.

[0024] Among them, the real-time skin impedance is obtained according to the real-time skin electrical impedance signal, and when the change value of the real-time skin impedance within a predetermined time interval is greater than a preset impedance change value threshold, the electric pulse output parameter is adjusted based on the feedback adjustment formula and the impedance change value.

[0025] Functions and Effects of the Invention

[0026] According to the present invention, an acupoint positioning and electric pulse regulation device and method based on impedance feedback include: a bioimpedance detection module, which has a flexible wearable hardware part, the flexible wearable hardware part has electrodes for collecting skin impedance signals, and the bioimpedance detection module is used to determine the target acupoint area where the electrodes are placed according to the impedance signals; an initial pulse output module, which is used to output a predetermined initial electric pulse signal to the two electrodes of the flexible wearable hardware part; a dynamic collaborative control module, which is used to adjust the electric pulse output parameters according to the real-time skin impedance signal collected by the electrodes after the initial electric pulse signal is applied to the target acupoint area through the electrodes; an electric pulse output module, which is used to output the electric pulse signal to the electrodes of the flexible wearable hardware part according to the adjusted electric pulse output parameters, wherein the dynamic collaborative control module obtains the real-time skin impedance according to the real-time skin impedance signal, and when the change value of the real-time skin impedance within a predetermined time interval is greater than the preset impedance change value threshold, the electric pulse output parameters are adjusted based on the feedback adjustment formula and the impedance change value. Therefore, the acupoint positioning and electric pulse regulation device and method based on impedance feedback of the present invention can quickly identify and accurately locate acupoints, adjust the electric pulse output parameters in real time, and improve the personalization and adaptability of treatment. When the patient's skin condition changes or the acupoint characteristics differ, the device can dynamically optimize the stimulation output through a feedback mechanism, significantly improving the treatment effect and patient comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a module schematic diagram of the acupoint positioning and electric pulse regulation device based on electrical impedance feedback in Example 1 of the present invention.

[0028] Figure 2 It is a flow chart of the acupoint positioning and electric pulse control method based on electrical impedance feedback in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate the acupoint positioning and electric pulse control device and method based on electrical impedance feedback of the present invention.

[0030] Example 1

[0031] Figure 1 It is a module schematic diagram of the acupoint positioning and electric pulse regulation device 10 based on electrical impedance feedback in Example 1 of the present invention.

[0032] like Figure 1 As shown, the acupoint positioning and electric pulse regulation device 10 based on impedance feedback in Example 1 of the present invention includes: a bioimpedance detection module 101, an initial pulse output module 102, a dynamic collaborative control module 103, an electric pulse output module 104, a parameter optimization module 105, a skin condition monitoring module 106, and a power management module 107.

[0033] Specifically, the bioelectrical impedance detection module 101 includes: a flexible wearable hardware part, a positioning indication part, a denoising unit and a classification and recognition unit.

[0034] The flexible wearable hardware part has electrodes for collecting skin impedance signals, and the bioimpedance detection module 101 is used to determine the target acupuncture point area for placing electrodes according to the impedance signals, wherein the electrodes for collecting skin impedance signals on the flexible wearable hardware part may be one or more. The electrodes of the flexible wearable hardware part are made of conductive fabric material, and the surface of the electrodes is coated with a nano-antioxidation layer to improve durability and conductivity, while avoiding skin allergies caused by long-term wearing.

[0035] The positioning indicator lights up green when the target acupuncture point area is positioned successfully, and lights up red when the target acupuncture point area is positioned unsuccessfully.

[0036] The denoising unit performs denoising on the electrical impedance signal, filters out environmental interference signals, and ensures the accuracy of the measured data.

[0037] The classification and recognition unit extracts the key features of the electrical impedance signal using the frequency response characteristics, and classifies and processes the key features to identify the target acupuncture point area, key features, including amplitude changes and frequency dependence of the low impedance area.

[0038] The bioelectrical impedance detection module 101 supports multi-frequency impedance measurement with a frequency range of 10kHz to 100kHz, and combines the following formula to achieve accurate identification of low impedance areas:

[0039]

[0040] Where R adj is the adjusted impedance value, f is the measurement frequency, C is the equivalent capacitance, d is the contact thickness between the skin and the electrode, α is the impedance characteristic attenuation coefficient, R meas is the collected impedance value.

[0041] The initial pulse output module 102 includes: an initial pulse parameter selection unit, an initial treatment duration selection unit and an output unit.

[0042] The initial pulse parameter selection unit selects the electric pulse amplitude and the electric pulse frequency according to the target acupuncture point area and calculates the current flowing through the skin.

[0043] The initial treatment duration selection unit is used to select the treatment duration.

[0044] The output unit outputs an electric pulse signal of a preset duration to the electrodes of the flexible wearable hardware part according to the electric pulse amplitude, frequency and current flowing through the skin.

[0045] After the initial electric pulse signal is applied to the target acupuncture point area through the electrode, the dynamic collaborative control module 103 adjusts the electric pulse output parameters according to the real-time skin electrical impedance signal collected by the electrode. Specifically, after the dynamic collaborative control module 103 outputs the electric pulse signal for a preset time, when the change value of the real-time skin impedance is greater than the preset impedance change value threshold, the electric pulse output parameters are adjusted based on the feedback adjustment formula and the impedance change value, where the feedback adjustment formula is as follows:

[0046] P(t)=P 0 +k·(R Ref -R t )

[0047] Where P(t) is the current power, P 0 is the basic power, R t is the real-time impedance value, R Ref is the reference impedance value, k is the adjustment coefficient, R Ref -R t The impedance change value, wherein the adjusted electrical pulse signal output parameters include frequency, amplitude and pulse width, so as to dynamically optimize the output power to ensure adaptation to different skin impedance states of patients.

[0048] The electric pulse output module 104 outputs an electric pulse signal to the dual electrodes of the flexible wearable hardware part according to the adjusted electric pulse output parameters. Specifically, the electric pulse signal is a bipolar rectangular wave signal, and the dynamic collaborative control module obtains the real-time skin impedance according to the real-time skin electrical impedance signal. When the change value of the real-time skin impedance within a predetermined time interval is greater than the preset impedance change value threshold, the electric pulse output parameter is adjusted based on the feedback adjustment formula and the impedance change value.

[0049] The electric pulse output module 104 supports dual-mode output, including a high-frequency low-intensity mode (10-50 Hz, 2-5 mA) and a low-frequency high-intensity mode (2-10 Hz, 10-20 mA), to meet different types of pain treatment needs.

[0050] The parameter optimization module 105 obtains patient response feedback and updates the electrical pulse output parameters according to the patient response feedback and the parameter optimization formula. The electrical pulse output module 104 is also used to output electrical pulse signals according to the electrical pulse output parameters updated by the parameter optimization module 105.

[0051] Specifically, the parameter optimization formula is as follows:

[0052]

[0053] Where T opt is the output parameter of the electric pulse signal, y i is the patient response feedback, f(χ i ,T) is the parameter model output, λ||T|| 2 It is a regularization term, and the parameters are continuously optimized through patient feedback to improve the therapeutic effect.

[0054] The skin condition monitoring module 106 detects the current moisture, temperature and contact quality of the skin to optimize the electrical pulse output parameters.

[0055] The power management module 107 monitors the power in real time and issues an alarm when the device is low on power. It has a fast charging function and can charge to 80% within 30 minutes.

[0056] The acupoint positioning and electric pulse control device 10 based on electrical impedance feedback also includes: a Bluetooth communication module, which connects the acupoint positioning and electric pulse control device 10 based on electrical impedance feedback and a host computer software system, and uploads the historical treatment data collected by the device to the host computer system. The host computer software system analyzes the historical treatment data through a machine learning algorithm to generate a personalized treatment plan. The host computer software system interface can also set a personalized treatment mode, including acupuncture simulation mode, muscle relaxation mode and rapid pain relief mode. The command is transmitted to the acupoint positioning and electric pulse control device based on electrical impedance feedback through the Bluetooth communication module, and the user preference can be saved for quick call, and the parameters can be dynamically adjusted according to the patient's real-time feedback. The Bluetooth communication module adopts the BLE 5.0 protocol, supports real-time data transmission with a delay of less than 10ms, and can protect the security of patient data through an encrypted communication mechanism.

[0057] The acupoint positioning and electric pulse regulation device 10 based on electrical impedance feedback supports six groups of independent electrode channels, and realizes synchronous stimulation of multiple acupoint areas through independent feedback loops to improve the treatment efficiency of multi-site pain management.

[0058] In the multi-acupoint stimulation scenario, this device uses multi-channel electrode independent control technology to act on multiple low-impedance acupoint areas at the same time. For areas that need enhanced stimulation, the device will give priority to increasing output parameters, such as increasing amplitude or pulse width; while for sensitive areas, the stimulation intensity is reduced to reduce patient discomfort. Through the Bluetooth communication module, patients or doctors can monitor treatment data in real time and adjust the stimulation mode to ensure that the treatment process is more personalized and efficient.

[0059] Figure 2 It is a flow chart of the acupoint positioning and electric pulse control method based on electrical impedance feedback in Example 1 of the present invention.

[0060] After the flexible wearable hardware is placed on the target acupuncture point area of ​​the skin, Figure 2 As shown, the acupoint positioning and electric pulse control method based on electrical impedance feedback specifically includes the following steps:

[0061] Step S201, measuring the initial skin impedance.

[0062] Step S202, judging whether the measured target acupoint area is an acupoint according to the measured initial skin impedance, when the judgment result is no, executing step S203; when the judgment result is yes, executing step S204.

[0063] Step S203, adjust the position of the electrode on the skin, and repeat steps S201 to S202 until the judgment result of step S202 is yes.

[0064] Step S204, selecting appropriate electric pulse amplitude and electric pulse frequency.

[0065] Step S205, calculating the current flowing through the skin.

[0066] Step S206, selecting the treatment duration, that is, the duration for the electrode to release the electrical pulse signal.

[0067] Step S207, starting treatment according to the selected electric pulse amplitude, electric pulse frequency and treatment duration, outputting a predetermined corresponding electric pulse signal to the electrode of the flexible wearable hardware part, taking it as the initial electric pulse signal, and applying it to the acupuncture point through the electrode to start treatment.

[0068] Step S208, determine whether the treatment time reaches the preset treatment time. The preset treatment time can be adjusted according to demand. In this embodiment, the preset treatment time is 5 minutes. If yes, execute step S209; if not, continue to accumulate treatment time until 5 minutes.

[0069] Step S209, measuring real-time skin impedance.

[0070] Step S210, determining whether the real-time skin impedance change value is greater than a preset impedance change value threshold, if the result is yes, executing step S211; if the result is no, executing step S212.

[0071] Step S211, adjusting the electric pulse output parameters based on the feedback adjustment formula and the real-time skin impedance change value.

[0072] Step S212, determine whether the treatment duration reaches the end duration, if so, end the treatment; if not, repeat steps S208-S212 until the treatment duration reaches the end duration.

[0073] Functions and Effects of the Embodiments

[0074] The acupoint positioning and electric pulse control device and method based on electrical impedance feedback of the present invention can quickly identify and accurately locate acupoints, make timely adjustments when positioning errors occur, and adjust the electric pulse output parameters in real time to improve the personalization and adaptability of treatment. When the patient's skin condition changes or the acupoint characteristics are different, the device can dynamically optimize the stimulation output through the feedback mechanism, significantly improving the treatment effect and patient comfort.

[0075] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An acupoint positioning and electric pulse control device based on electrical impedance feedback, characterized in that: include: A bioelectrical impedance detection module, comprising a flexible wearable hardware portion, wherein the flexible wearable hardware portion comprises electrodes for collecting skin electrical impedance signals, and the bioelectrical impedance detection module is used to determine a target acupuncture point area where the electrodes are placed according to the electrical impedance signals; An initial pulse output module, used to output a predetermined initial electrical pulse signal to the electrodes of the flexible wearable hardware part; A dynamic collaborative control module, configured to adjust the electric pulse output parameters according to the real-time skin electrical impedance signal collected by the electrode after the initial electric pulse signal is applied to the target acupuncture point area through the electrode; an electric pulse output module, used to output electric pulse signals to the electrodes of the flexible wearable hardware part according to the adjusted electric pulse output parameters, Among them, the dynamic collaborative control module obtains real-time skin impedance according to the real-time skin electrical impedance signal, and when the change value of the real-time skin impedance within a predetermined time interval is greater than a preset impedance change value threshold, the electric pulse output parameter is adjusted based on the feedback adjustment formula and the impedance change value.

2. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 1, Features: in, The bioelectrical impedance detection module also includes: A denoising unit, used for performing denoising processing on the electrical impedance signal; The classification and identification unit is used to extract the key features of the electrical impedance signal by using the frequency response characteristics, and classify the key features to identify the target acupuncture point area, wherein the key features include the amplitude change and frequency dependence of the low impedance area.

3. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 2, characterized in that: in, The bioelectrical impedance detection module supports multi-frequency impedance measurement with a frequency range of 10kHz to 100kHz, and combines the following formula to achieve accurate identification of the low impedance area: Where R adj is the adjusted impedance value, f is the measurement frequency, C is the equivalent capacitance, d is the contact thickness between the skin and the electrode, α is the impedance characteristic attenuation coefficient, R meas is the collected impedance value.

4. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 1, Features: in, The initial pulse output module comprises: an initial pulse parameter selection unit, for selecting the electric pulse amplitude and the electric pulse frequency according to the target acupuncture point area, and calculating the current flowing through the skin; An initial treatment duration selection unit is used to select the treatment duration; The output unit is used to output an electric pulse signal of a preset duration to the electrodes of the flexible wearable hardware part according to the electric pulse amplitude, frequency and the current flowing through the skin.

5. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 1, characterized in that: in, The dynamic collaborative control module is used to adjust the electric pulse output parameter based on a feedback adjustment formula and the impedance change value after outputting the electric pulse signal for a preset time period, when the change value of the real-time skin impedance is greater than a preset impedance change value threshold, wherein the feedback adjustment formula is as follows: P(t)=P0+k·(R Ref -R t ) Where P(t) is the current power, P0 is the basic power, R t is the real-time impedance value, R Ref is the reference impedance value, k is the adjustment coefficient, R Ref -R t is the impedance change value, wherein the adjusted output parameters of the electric pulse signal include frequency, amplitude and pulse width.

6. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 1, characterized in that: Also includes: a parameter optimization module, for obtaining patient response feedback and updating the electrical pulse output parameters according to the patient response feedback and the parameter optimization formula, The electric pulse output module is also used to output an electric pulse signal according to the electric pulse output parameters updated by the parameter optimization module.

7. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 6, characterized in that: in, The parameter optimization formula is as follows: Where T opt is the output parameter of the electric pulse signal, y i is the patient response feedback, f(x i ,T) is the parameter model output, λ||T|| 2 is the regularization term.

8. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 1, characterized in that: Also includes: Skin condition monitoring module, used to detect the current moisture, temperature and contact quality of the skin to optimize the electrical pulse output parameters, The dynamic collaborative control module is also used to adjust the electrical pulse output parameters according to the current humidity, temperature and contact quality of the skin.

9. The acupoint positioning and electric pulse control device based on electrical impedance feedback according to claim 1, characterized in that: Also includes: The power management module is used to monitor the power in real time and issue an alarm when the device is low on power.

10. A method for acupoint positioning and electric pulse control based on electrical impedance feedback, characterized in that: include: Determining a target acupuncture point area for placing the electrode according to the electrical impedance signal; Outputting a predetermined initial electrical pulse signal to the electrodes of the flexible wearable hardware portion; After the initial electric pulse signal is applied to the target acupuncture point area through the electrode, adjusting the electric pulse output parameter according to the real-time skin electrical impedance signal collected by the electrode; Outputting electric pulse signals to the electrodes of the flexible wearable hardware part according to the adjusted electric pulse output parameters, Wherein, the real-time skin impedance is obtained according to the real-time skin electrical impedance signal, and when the change value of the real-time skin impedance within a predetermined time interval is greater than a preset impedance change value threshold, the electric pulse output parameter is adjusted based on a feedback adjustment formula and the impedance change value.

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