Touch force feedback simulation method and system based on pressure deformation signal

Abstract

The application provides a touch force feedback simulation method and system based on pressure deformation signals, relates to the technical field of touch interaction and tactile feedback, and comprises a data acquisition process: configuring a sensor to collect the physical state of a touch interface to obtain instantaneous pressure and deformation signals; an impedance compensation process comprises the following steps: step 1, obtaining instantaneous signals; step 2, constructing a dynamic hysteresis loop model; step 3, solving a viscous energy loss value; step 4, generating an energy compensation waveform; and step 5, driving an actuator to generate reverse damping vibration. The application quantifies the viscous loss of a material through a physical phase space model, accurately injects reverse energy, and effectively solves the problems of touch hysteresis and soft collapse of a touch interface caused by viscoelasticity.

Description

Technical Field

[0001] This invention relates to the field of touch interaction and haptic feedback technology, and in particular to a touch force feedback simulation method and system based on pressure deformation signals. Background Technology

[0002] As a key device for enhancing the immersive experience of human-computer interaction, the realism of tactile force feedback systems in fields such as smart mobile terminals, virtual reality devices, and automotive touch control directly depends on the ability to reproduce the physical characteristics of touch operations. Therefore, accurate energy compensation is crucial to ensuring the crispness of the touch.

[0003] Existing feedback simulation methods have many problems. For example, they often use a single pressure threshold or a linear mapping mechanism based on time-domain waveforms. Due to inherent defects such as high internal friction and stress relaxation in the composite structure layer of the touch interface, it is difficult to fully reflect the rheological characteristics of the material during the pressing process. Especially when there is a large difference between the user's pressing force and speed, the system cannot sense and compensate for the energy loss caused by the material viscosity, and cannot effectively correct the tactile blur and lag caused by signal trailing. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a touch force feedback simulation method and system based on pressure deformation signal, which can solve the technical problems existing in the prior art.

[0005] A first aspect of this invention proposes a touch force feedback simulation method based on pressure deformation signals, comprising: configuring a pressure sensor and a deformation detection module to collect physical state data of a touch interface; and triggering an impedance compensation process in response to a detected touch operation, the impedance compensation process comprising: step 1, acquiring an instantaneous pressure signal output by the pressure sensor and an instantaneous deformation signal output by the deformation detection module; step 2, mapping the instantaneous pressure signal and the instantaneous deformation signal to a two-dimensional phase space, and constructing a dynamic hysteresis loop model through discrete point fitting processing; step 3, performing area integration on the dynamic hysteresis loop model to calculate the viscous energy loss value of the current touch operation; step 4, generating an energy compensation waveform based on the viscous energy loss value and a preset rheological impedance model; and step 5, outputting the energy compensation waveform to a tactile feedback actuator to drive the tactile feedback actuator to generate reverse damped vibration.

[0006] Preferably, constructing a dynamic hysteresis loop model includes: establishing an energy phase plane coordinate system with pressure parameters as the vertical axis and deformation parameters as the horizontal axis; tracking the change trajectories of instantaneous pressure signals and instantaneous deformation signals in real time in the energy phase plane coordinate system; and reconstructing the change trajectories using a closed curve fitting algorithm to generate a closed dynamic hysteresis loop model.

[0007] Preferably, generating an energy compensation waveform includes: using a fractional derivative algorithm to decompose the instantaneous pressure signal into elastic and viscous components; calculating the reverse force parameter to counteract the viscous component based on the viscous energy loss value; and performing pre-distortion processing on a preset base waveform according to the reverse force parameter to generate an energy compensation waveform.

[0008] Preferably, the method further includes an environmental adaptability correction process: acquiring current ambient temperature data; using the ambient temperature data as a correction coefficient to adjust the elastic modulus parameter of the rheological impedance model; wherein, a preset low temperature threshold is less than a preset high temperature threshold; if the ambient temperature data is lower than the preset low temperature threshold, the weight of the elastic modulus parameter is increased; if the ambient temperature data is higher than the preset high temperature threshold, the weight of the elastic modulus parameter is decreased; if the ambient temperature data is greater than or equal to the preset low temperature threshold and less than or equal to the preset high temperature threshold, the elastic modulus parameter remains unchanged.

[0009] Preferably, the process also includes a health monitoring procedure: calculating the feature area of ​​the dynamic hysteresis loop model; if the feature area is greater than a preset abnormal threshold, generating a structural layer peeling warning signal; if the feature area is less than or equal to the abnormal threshold, maintaining the current feedback strategy.

[0010] Preferably, the process also includes an aging calibration procedure: obtaining a preset reference hysteresis loop characteristic; periodically calculating the geometric deviation between the dynamic hysteresis loop model and the reference hysteresis loop characteristic; and updating the compensation coefficient of the rheological impedance model based on the geometric deviation value to maintain the consistency of tactile feedback.

[0011] Preferably, the energy compensation waveform has a phase characteristic opposite to the phase lag direction of the viscous energy loss, and the energy integral value of the energy compensation waveform is equal to the viscous energy loss value.

[0012] A second aspect of this invention proposes a touch force feedback simulation system based on pressure deformation signals, comprising: a data acquisition unit for acquiring instantaneous pressure signals output by a pressure sensor and instantaneous deformation signals output by a deformation detection module; a phase space modeling unit for mapping the instantaneous pressure signals and instantaneous deformation signals to a two-dimensional phase space and constructing a dynamic hysteresis loop model through discrete point fitting processing; an energy calculation unit for performing area integration on the dynamic hysteresis loop model to calculate the viscous energy loss value of the current touch operation; a waveform synthesis unit for generating an energy compensation waveform based on the viscous energy loss value and a preset rheological impedance model; and a drive control unit for outputting the energy compensation waveform to a tactile feedback actuator.

[0013] Preferably, the data acquisition unit includes: a pressure sensing circuit connected to the bottom of the touch panel for acquiring instantaneous pressure signals; and a capacitor plate spacing detection circuit connected to the composite structure layer of the touch panel for acquiring instantaneous deformation signals.

[0014] Preferably, the waveform synthesis unit operates in a field-programmable gate array (FPGA) or a high-frequency microcontroller (MCU) to achieve a microsecond-level waveform synthesis response.

[0015] Beneficial effects

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This invention effectively solves the problems of tactile lag and soft collapse caused by traditional tactile feedback relying solely on pressure thresholds by constructing a physical phase space model and a dynamic hysteresis loop integration mechanism. Unlike simple time-domain waveform analysis, this scheme maps instantaneous pressure signals and deformation signals to a two-dimensional energy phase space, reconstructs the dynamic hysteresis loop reflecting the nonlinear mechanical response of the material using a closed curve fitting algorithm, and accurately quantifies viscous energy loss through area integration calculation, thereby achieving precise compensation for the viscoelasticity of touch interface materials from a physical essence.

[0018] 2. This invention introduces fractional derivative decomposition and reverse damping compensation strategies, which greatly improves the crispness and realism of tactile feedback. By establishing a fractional rheological model, the total pressure signal is accurately decomposed into elastic and viscous components, and the reverse force parameters that can counteract the viscous components are calculated. Combined with pre-distortion processing based on actuator inverse dynamics, this method can effectively eliminate the blurriness caused by signal trailing and reproduce a realistic rigid mechanical button feel on a flexible screen.

[0019] 3. This invention establishes an environmental adaptability correction and aging closed-loop calibration mechanism, which gives the system consistent experience under complex working conditions. The system uses ambient temperature data to dynamically adjust the elastic modulus parameter of the rheological impedance model to counteract the influence of temperature changes on the storage modulus of polymer materials. At the same time, it periodically calculates the geometric deviation between the current hysteresis loop and the reference feature, and automatically updates the compensation coefficient to offset the performance degradation caused by material physical relaxation, ensuring a continuous and stable tactile feedback effect.

[0020] This invention employs capacitor micro-deformation detection and health monitoring technology based on existing structures, achieving highly integrated physical sensing and device self-diagnosis. By reusing the parasitic capacitance of the touch panel and using a second-order nonlinear fitting algorithm to solve the instantaneous deformation, high-precision displacement data can be obtained without increasing the thickness of the sensor. At the same time, by using the normalized specific damping capacity as a judgment indicator, it can sensitively identify abnormal states such as structural layer peeling or bubbles, ensuring the long-term reliable operation of the touch module. Attached Figure Description

[0021] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0022] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts disclosed in this invention.

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention.

[0026] Reference manual attached Figure 1 .

[0027] This invention provides a touch force feedback simulation method based on pressure deformation signals, comprising: configuring a pressure sensor and a deformation detection module to collect physical state data of a touch interface; in response to a detected touch operation, triggering an impedance compensation process, the impedance compensation process comprising: step 1, acquiring the instantaneous pressure signal output by the pressure sensor and the instantaneous deformation signal output by the deformation detection module; step 2, mapping the instantaneous pressure signal and the instantaneous deformation signal to a two-dimensional phase space, and constructing a dynamic hysteresis loop model through discrete point fitting processing; step 3, performing area integration on the dynamic hysteresis loop model to calculate the viscous energy loss value of the current touch operation; step 4, generating an energy compensation waveform based on the viscous energy loss value and a preset rheological impedance model; step 5, outputting the energy compensation waveform to a tactile feedback actuator to drive the tactile feedback actuator to generate reverse damped vibration;

[0028] This embodiment details the specific execution logic of the aforementioned touch force feedback simulation method based on pressure deformation signals. This method aims to break away from the traditional linear mapping mechanism of tactile feedback that relies solely on pressure thresholds. By constructing a physical phase space model, it addresses the tactile lag and softness issues caused by the viscoelasticity of materials at the touch interface. First, the system configures a highly sensitive physical sensing unit at the underlying hardware level, namely a pressure sensor and a deformation detection module, to synchronously acquire a multi-dimensional data set that fully describes the mechanical properties of the touch interface under force at a microsecond-level sampling rate, ensuring strict alignment of the two physical quantities in the time domain. In response to the detection of a touch operation via the rising edge of the pressure sensor signal and the pressure value exceeding a preset noise threshold, the system immediately triggers an impedance compensation process. This process aims to calculate and generate a compensation that can offset the impact on the touch interface. The active force of material physical damping is then assessed. Next, the data acquisition unit reads the current physical quantities in real time, acquiring the instantaneous pressure signal characterizing the normal force applied by the user's finger to the touch interface, and the instantaneous deformation signal characterizing the microscopic vertical displacement of the touch interface at the force point. Subsequently, the system performs a dimensionality upgrade, no longer analyzing the time-domain waveform separately, but constructing a two-dimensional Cartesian coordinate system with the deformation signal as the horizontal axis and the pressure signal as the vertical axis, i.e., the energy phase space. In this space, a complete press-and-release operation forms a closed loop trajectory due to the viscoelasticity of the touch interface material, i.e., a dynamic hysteresis loop model, which intuitively reflects the nonlinear mechanical response of the material. Based on this, the system performs area integration on the dynamic hysteresis loop model, specifically using the Discrete Green's formula for the discrete point set in the phase space. Perform the calculation:

[0029] ;

[0030] Defined as To ensure the path is closed;

[0031] Defined as a complete touch operation, that is, the total number of sampling points collected by the system from the time the pressure signal exceeds the trigger threshold to the time it returns to zero. This value changes dynamically with the duration of the touch.

[0032] The viscous energy loss of this touch operation is quantified by calculating the geometric area enclosed by the dynamic hysteresis loop. It must be clearly stated that although the calculation uses the geometric term "area," the area integral enclosed by this closed curve in phase space with force as the vertical axis and displacement as the horizontal axis represents the actual energy loss. In physical essence, this strictly corresponds to the work done by non-conservative forces in a single press-release cycle, i.e., energy dissipation, with dimensions in units of energy, i.e., Joules or N·mm, rather than purely geometric area; here... That is, phase space area This is the unnormalized absolute energy value, reflecting the actual physical dissipation and suitable for directly driving energy compensation. However, for subsequent processes involving material property analysis, such as health monitoring or aging calibration, this value needs to be normalized to eliminate the influence of operational force. This definition of physical essence ensures that the model calculation results can be directly mapped to the energy value that needs to be compensated. This loss value refers to the mechanical energy dissipated as heat energy due to factors such as internal friction of the touch interface material and creep of the adhesive layer during a single touch operation. Furthermore, based on the principle of energy conservation and combined with a preset rheological impedance model, the system calculates the energy that needs to be backfilled and generates an energy compensation waveform. The design goal of this waveform is to inject mechanical energy into the touch interface in the same amount as the viscous energy loss value, but in the opposite direction, to artificially create the physical characteristics of zero loss or even negative loss. The rheological impedance model adopts the fractional-order Kelvin-Voigt model, and its mathematical expression is:

[0033] ;

[0034] Total pressure;

[0035] For deformation;

[0036] The elastic coefficient;

[0037] It is the viscous damping coefficient;

[0038] The order of the fractional derivative is 0.3-0.7.

[0039] Model parameters , , Frequency scanning experiments were conducted on touch interface material samples using a dynamic thermomechanical analyzer, and the storage modulus and loss modulus curves were obtained by fitting them using the least squares method. When generating the energy compensation waveform, the viscous component was separated and the reverse force was calculated based on this model. This addresses the issue of varying user pressure levels in practical applications. The haptic feedback can fluctuate significantly, with light presses resulting in less energy loss and heavy presses in greater loss, potentially leading to inconsistent haptic feedback. This embodiment addresses this by introducing a consistency-of-experience correction mechanism on top of the basic energy conservation logic: the system sets a minimum perceived energy threshold. This threshold, determined through psychophysical experiments, is the minimum mechanical energy value that a human fingertip can perceive on the touch interface; for example, its typical value was determined to be 5 μJ through a series of tests. If the calculated... Below The system will be based on Instead Generate a compensation waveform, or introduce a nonlinear gain function to boost small signals, thereby ensuring that even slight touches trigger clear haptic feedback, avoiding the experiential imbalance caused by relying solely on absolute physical quantities; to strictly enforce energy conservation and ensure code reproducibility, the system performs specific voltage amplitude mapping calculations in this step: assuming the haptic feedback actuator, such as a linear motor, has an electromechanical conversion efficiency of... Dimensionless, the real part of the equivalent electrical impedance is ,unit The preset normalized shape function of the compensation waveform is For example, the normalized Ricker wavelet, where the integral term is explicitly stated here. The physical dimension is time, unit: second, representing the time-domain cumulative effect of waveform energy under normalized amplitude, then the system calculates the driving voltage amplitude. The formula is:

[0040] ;

[0041] This formula ensures that the energy integral value of the output waveform, after being converted into mechanical work, is strictly matched. Finally, the drive control unit converts the generated energy compensation waveform into a voltage signal, which drives the haptic feedback actuator to produce reverse damping vibration. This vibration is not a normal vibration prompt, but a precise physical displacement compensation that acts on the moment the finger leaves the touch interface.

[0042] The construction of a dynamic hysteresis loop model includes: establishing an energy phase plane coordinate system with pressure parameters as the vertical axis and deformation parameters as the horizontal axis; tracking the change trajectories of instantaneous pressure signals and instantaneous deformation signals in real time in the energy phase plane coordinate system; and reconstructing the change trajectories using a closed curve fitting algorithm to generate a closed dynamic hysteresis loop model.

[0043] This embodiment further specifies the steps for constructing a dynamic hysteresis loop model. This step aims to transform discrete time-domain signals into a geometric model with energy physical meaning. First, the system allocates a dedicated data buffer in memory and establishes a virtual energy phase plane coordinate system, where the vertical axis is defined as physical force (in N) and the horizontal axis is defined as physical deformation displacement (in mm). During this process, the system calls preset calibration coefficients to map the raw instantaneous pressure signals collected by sensors, such as voltage values ​​or ADC code values, to the instantaneous deformation signals using physical dimensions, ensuring that the point set in the coordinate system... This approach possesses genuine mechanical significance, ensuring that the calculated hysteresis loop area physically corresponds precisely to the mechanical energy loss, i.e., Joules, avoiding dimensional errors caused by directly using the original signal. Next, with each user's press operation, the system tracks the changes in instantaneous pressure and deformation signals in real-time using high-frequency sampling points in the coordinate system. During the loading phase, the trajectory extends along the upper right, its slope representing the instantaneous stiffness of the material. During the unloading phase, the trajectory returns along the lower left; due to stress relaxation, the unloading path is typically lower than the loading path. Subsequently, considering that sampling noise may cause the original trajectory to become discrete and jittery, the system utilizes a closed-curve fitting algorithm, specifically employing a Savitzky-Golay smoothing filter to denoise the sequence. Its core convolution formula is:

[0044] ;

[0045] in the formula As a general variable, in this embodiment, the system maps the instantaneous pressure signal sequences respectively. and instantaneous deformation signal sequence As Substituting the values ​​into the above formula, independent filtering is performed to ensure signal-to-noise ratio matching when the two components are combined in the phase plane; this filter removes high-frequency jitter while preserving peak and trough characteristics; after processing, the system executes forced closure logic, i.e., at the end of the trajectory... From the starting point Linear interpolation paths are inserted between them to reconstruct a mathematically continuous and integrable closed dynamic hysteresis loop model.

[0046] This embodiment can intuitively capture the rheological characteristics of materials by reconstructing the trajectory of the phase plane. The width of the hysteresis loop directly reflects the magnitude of the damping, and the change in the slope reflects the nonlinearity of the stiffness. This geometric modeling method provides a reliable mathematical basis for subsequent accurate calculation of viscous loss and ensures the robustness of energy calculation in complex touch environments.

[0047] The process of generating an energy compensation waveform includes: using a fractional derivative algorithm to decompose the instantaneous pressure signal into elastic and viscous components; calculating the reverse force parameters to counteract the viscous components based on the viscous energy loss value; and performing pre-distortion processing on a preset base waveform according to the reverse force parameters to generate the energy compensation waveform.

[0048] This embodiment further specifies the step of generating the energy compensation waveform; this step employs advanced fractional calculus theory to accurately separate the physical components causing tactile lag; firstly, the system introduces a fractional Kelvin-Voigt model, using a fractional derivative algorithm to decompose the total pressure signal into two parts:

[0049] ;

[0050] The source is real-time data collection, and its physical meaning is the instantaneous deformation signal of the touch panel at the point of force application, i.e., the vertical displacement.

[0051] The source is calculated, and its physical meaning is the elastic component, which is proportional to the deformation and represents the ideal rigid feel;

[0052] The source is calculated, and its physical meaning is the viscous component, which is proportional to the fractional derivative of the deformation and represents hysteresis damping.

[0053] The value is derived from the material properties, is dimensionless, and ranges from 0.3 to 0.7. Its physical meaning is the order of the fractional derivative, representing the viscoelastic characteristics of the material.

[0054] The source is a preset parameter, the unit is N / mm, and the physical meaning is the elastic coefficient;

[0055] Source: Preset parameters, unit: N·s / mm, in physical terms, refers to the viscous damping coefficient;

[0056] The above parameters The specific values ​​were obtained by performing frequency scanning experiments on the touch interface material samples using a dynamic thermomechanical analyzer, and by fitting the storage modulus and loss modulus curves obtained from the experiments using the least squares method. Based on this, in order to realize the real-time calculation of the above fractional derivatives in a digital computing platform, such as an FPGA or MCU, this embodiment uses the Grünwald-Letnikov G-L definition for discretization processing; specifically, time... place The first derivative is approximately in weighted sum form:

[0057] ;

[0058] The sampling period, for example, 10. s, The principle for setting the memory length is as follows: Greater than the material's stress relaxation time constant, for example, taking ;

[0059] The weighted coefficients of the fractional derivatives are calculated according to the Grünwald-Letnikov definition, and their expression is: ,in It is the Gamma function;

[0060] To facilitate implementation in embedded systems, the absolute value of the coefficients can be calculated using the following recursive relationship. ,in ,but The system stores the most recent data through shift registers. Historical deformation data Perform signed convolution operations in real time to obtain viscous components. Subsequently, the system locks onto the target of eliminating the viscous component and, based on the viscous energy loss value, calculates the parameters of the reverse force used to counteract the viscous component. In this step, to address the mismatch between the user's press time domain (typically several hundred milliseconds) and the haptic feedback time domain (typically several milliseconds), the system does not directly use historical records. Instead of using sequences, a feature mapping strategy is employed: the system first reads a preset basic waveform. The corresponding ideal displacement trajectory sequence The trajectory is stored in ROM and represents the displacement curve of a standard rigid click. Next, the system uses the aforementioned fractional-order algorithm to calculate the theoretical viscous drag sequence generated by this ideal trajectory under the current material properties.

[0061] ;

[0062] Calculate the energy gain coefficient This coefficient ensures that the compensated energy matches the actual measured energy loss. Equal; finally determine the sequence of reverse force parameters. Finally, the system performs pre-distortion processing on the preset base waveform based on the reverse force parameters; this processing aims to counteract the physical inertia of the actuator itself and the transmission attenuation of the screen, specifically employing a superposition algorithm based on the actuator's inverse dynamics model; assuming the actuator is approximately a first-order inertial system at low frequencies, its transfer function is... In order to increase the output force Following the target compensation force Required drive voltage It should satisfy the inverse transformation ; this time-domain relationship

[0063] Discretization is performed, and the preset basic waveform is assumed to be... Specifically, a trapezoidal or half-sine wave with an amplitude of 3.0V to 5.0V and a duration of 5ms to 15ms, such as a standard square wave pulse, serves as the main vibration carrier for tactile feedback; the resulting final energy compensation waveform Using the following discrete difference equation, and utilizing the above-generated... isomorphic Sequence generation:

[0064] ;

[0065] The index of the waveform synthesis sequence, with a length equal to... Consistent;

[0066] The waveform output sampling period;

[0067] The voltage-to-force conversion coefficient corresponds to the one in the inverse model described above. Its specific value comes from the offline calibration of the haptic feedback actuator, and the calculation formula is as follows: ,in This is the maximum drive voltage of the actuator. This coefficient represents the maximum electromagnetic force that the actuator can output at this voltage. It is used to linearly map the calculated mechanical parameters to a voltage amplitude that the circuit can recognize.

[0068] The actuator acceleration time constant is defined as the time required for the actuator to reach 63.2% of its steady-state value under the drive of a step signal. It is derived from the actuator's manufacturer's specifications or measured through step response experiments. The value is usually in the range of 2ms to 10ms. It is used to characterize and compensate for the physical response hysteresis of the actuator caused by the mass of the mover.

[0069] The differential term in the formula is used to provide a high-frequency pre-emphasis pulse to overcome the static friction of the actuator, giving it an asymmetric characteristic with a steep leading edge and a reverse damping pulse at the trailing edge.

[0070] This embodiment utilizes a fractional derivative algorithm to describe the complex rheological properties of polymer materials more accurately than the traditional integer derivative model. This mathematical decomposition and discretization enables the compensation waveform to accurately eliminate viscous components and retain only elastic components, thereby restoring an extremely realistic feel of rigid mechanical buttons on a flexible screen and eliminating the blurriness caused by signal trailing.

[0071] It also includes an environmental adaptability correction process: acquiring the current ambient temperature data; in step 4, using the ambient temperature data as a correction coefficient to adjust the elastic modulus parameter of the rheological impedance model; wherein, the preset low temperature threshold is less than the preset high temperature threshold; if the ambient temperature data is lower than the preset low temperature threshold, the weight of the elastic modulus parameter is increased; if the ambient temperature data is higher than the preset high temperature threshold, the weight of the elastic modulus parameter is decreased; if the ambient temperature data is greater than or equal to the preset low temperature threshold and less than or equal to the preset high temperature threshold, the elastic modulus parameter remains unchanged.

[0072] This embodiment further improves the method by adding an environmental adaptability correction process. This process aims to address the significant impact of temperature changes on the storage modulus of polymer materials. First, the system acquires the current ambient temperature data through a built-in thermistor or temperature sensor. Next, the system uses this temperature data as a correction coefficient to adjust the elastic modulus parameter of the rheological impedance model; the specific adjustment strategy adopts a piecewise linear compensation algorithm: in response to ambient temperature data falling below a preset low-temperature threshold... For example, 10°C indicates that the touch interface material has become harder and more brittle. The system increases the elastic modulus parameter according to the following formula. Weights:

[0073] ;

[0074] These are standard parameters;

[0075] Low-temperature hardening coefficient, unit: For example, 0.02 / ℃, to match the high stiffness prediction of the model; in response to ambient temperature data exceeding a preset high temperature threshold. For example, 40°C indicates that the touch interface material softens and becomes more viscous. The system reduces the elastic modulus parameter according to the following formula. The weight of the coefficient is adjusted accordingly, and the viscous damping coefficient is increased accordingly. Weights:

[0076] ;

[0077] ;

[0078] This is the high-temperature softening coefficient, in units of: When the ambient temperature data is in the normal temperature range, that is, greater than or equal to the preset low temperature threshold and less than or equal to the preset high temperature threshold, the system keeps the elastic modulus parameter unchanged.

[0079] To ensure the accurate acquisition of the aforementioned environmental adaptability parameters and support code reproduction, this embodiment discloses a specific calibration experimental procedure: A dynamic thermomechanical analyzer is used to perform temperature scanning tests on the optical adhesive (OCA) or cover material used in the touch panel, with a frequency of 10Hz, a heating rate of 2℃ / min, and a temperature range covering -20℃ to 60℃; the storage modulus is recorded. A curve showing how temperature changes; definition for The value represents the temperature at which the temperature rises by 20% relative to room temperature (25°C); definition. for The temperature at which the value decreases by 20% relative to room temperature; for the coefficient Select The following data segment was fitted using a linear regression formula. The slope is obtained; similarly, by fitting... The above data segments yielded and The fitted physical slope value is written into the system's non-volatile memory as an operating parameter.

[0080] It also includes a health monitoring process: calculating the feature area of ​​the dynamic hysteresis loop model; if the feature area is greater than the preset abnormal threshold, generating a structural layer peeling warning signal; if the feature area is less than or equal to the abnormal threshold, maintaining the current feedback strategy.

[0081] This embodiment further extends the method by introducing a health monitoring process. This process uses physical parameters calculated by the algorithm as the basis for device self-diagnosis. First, the system monitors in real time the characteristic area of ​​the dynamic hysteresis loop model calculated in step 3. Here, the characteristic area physically corresponds to the absolute integral area of ​​the hysteresis loop. However, in health monitoring scenarios, to prevent issues caused by users pressing hard, When the area increases naturally but falsely triggers a structural layer peeling warning, the system cannot directly use the absolute area as the basis for judgment. Instead, it performs normalization correction. The system adds a normalization step here: the system simultaneously reads the peak pressure of this operation. and peak deformation The specific damping capacity is calculated as a judgment indicator, and the calculation formula is as follows:

[0082] ;

[0083] This indicator eliminates the influence of the input energy magnitude and purely reflects the material's dissipation characteristics; subsequently, the system executes anomaly detection logic; in response to the normalized indicator... greater than the preset abnormal threshold For example, a value of 0.4, based on the loss factor calibration of healthy screen materials, indicates an abnormally increased energy loss under the same unit elastic potential energy. Physically, this corresponds to a sharp increase in interlayer friction caused by glue failure, blistering, or delamination between screen structural layers. The system generates a structural layer peeling warning signal to prompt the user for repair or to record a fault log in the background. In response to a feature area less than or equal to the abnormal threshold, the system determines the screen structure is healthy and maintains the current feedback strategy. Regarding the abnormal threshold... The rigorous acquisition method, as described in this embodiment, employs statistical process control: 1000 samples of high-quality touch modules are selected and subjected to pressure tests under standard test pressure; the average specific damping capacity of the sample group is then calculated. and standard deviation Considering that structural layer peeling is a unilateral anomaly, the following settings are made: This is the 6 sigma level, ensuring a false alarm rate of less than three parts per million under healthy conditions; simultaneously, verification is performed by artificially creating bubble defect samples to ensure the defect samples are... The value is significantly higher than the threshold.

[0084] It also includes an aging calibration process: obtaining a preset reference hysteresis loop characteristic; periodically calculating the geometric deviation between the dynamic hysteresis loop model and the reference hysteresis loop characteristic; updating the compensation coefficient of the rheological impedance model based on the geometric deviation value to maintain the consistency of tactile feedback;

[0085] This embodiment further improves the method by adding an aging calibration process. This process aims to combat the degradation of physical performance after long-term use of the equipment. First, the system acquires the stored preset reference hysteresis loop characteristics, where the reference characteristics are defined as a dimensionless reference loss factor. Instead of absolute area; then, the system periodically, specifically when the system's internal cumulative press count register... mold For example, every 10,000 times, when the value equals 0, the geometric deviation between the current dynamic hysteresis loop model and the baseline hysteresis loop characteristics is calculated; to avoid calculation errors caused by different pressure levels in a single press, the system adopts a normalized deviation calculation method: first, the equivalent loss factor of the current operation is calculated. Then calculate its relative deviation from the benchmark value. Subsequently, the system updates the compensation coefficients of the rheological impedance model based on this geometric deviation value; if This indicates that with increased hysteresis and material relaxation, the system updates the viscous damping coefficient in the rheological impedance model according to the proportional-integral (PI) strategy. :

[0086] ;

[0087] The preset adjustment gain is, for example, 0.1; if This indicates that the hysteresis has not increased or is within the measurement error range, and the system maintains its current coefficient unchanged. To avoid unnecessary parameter jitter;

[0088] Meanwhile, to prevent coefficient updates from overflowing due to sensor drift, the system sets a safety saturation boundary, that is, if the calculated... Then a mandatory order ,in These are the initial factory values; as the screen ages, it typically relaxes, the hysteresis loop becomes larger and its slope decreases, and the system automatically increases the compensation strength using the above formula to counteract the effects of aging; this is for adjusting the gain. The determination of the system's stability boundary is not based on empirical estimation in this embodiment, but rather on a calculation method based on the system's stability boundary: The discrete-domain transfer function of the closed-loop feedback system is constructed, and the system poles are analyzed using the Julius criterion; a target convergence rate is set while ensuring the system does not diverge, for example, eliminating 90% of the deviation within 500 pressing cycles; simulation is then used to... Set as critical gain 0.5 times, or by formula Calculation, where The desired deviation decay time constant is expressed in the number of calibration cycles, thus achieving a mathematically optimal balance between rapid calibration and prevention of parameter oscillations.

[0089] The energy compensation waveform has a phase characteristic opposite to the phase lag direction of the viscous energy loss, and the energy integral value of the energy compensation waveform is equal to the viscous energy loss value.

[0090] This embodiment further defines the physical characteristics of the energy compensation waveform. This definition ensures that the compensation signal conforms to the law of conservation of physical energy. First, regarding the phase characteristics, since viscoelastic materials cause the response to lag behind the excitation, the system sets the phase angle of the energy compensation waveform to a negative lag angle, that is, it has a phase characteristic opposite to the phase lag direction generated by viscous energy loss. Thus, after superposition, the phase angle of the total response approaches zero, simulating a purely elastic response. Second, regarding the energy amplitude, the system controls the energy integral value of the energy compensation waveform to be strictly equal to the calculated viscous energy loss value, ensuring that the total energy of the system is conserved, without generating unnecessary oscillations or leaving any uncompensated damping.

[0091] This embodiment distinguishes itself from ordinary vibration enhancement technology through precise phase offset and energy matching; it does not simply amplify vibration, but performs precise physical energy offset, thereby achieving extremely high fidelity tactile reproduction and avoiding the unnatural feeling caused by overshoot or underdamping.

[0092] This invention also provides a touch force feedback simulation system based on pressure deformation signals, comprising: a data acquisition unit for acquiring instantaneous pressure signals output by a pressure sensor and instantaneous deformation signals output by a deformation detection module; a phase space modeling unit for mapping the instantaneous pressure signals and instantaneous deformation signals to a two-dimensional phase space and constructing a dynamic hysteresis loop model through discrete point fitting processing; an energy calculation unit for performing area integration on the dynamic hysteresis loop model to calculate the viscous energy loss value of the current touch operation; a waveform synthesis unit for generating an energy compensation waveform based on the viscous energy loss value and a preset rheological impedance model; and a drive control unit for outputting the energy compensation waveform to a haptic feedback actuator.

[0093] This embodiment discloses a touch force feedback simulation system based on pressure deformation signals that performs the above-described method. The system's logical architecture consists of multiple core units working collaboratively. First, the data acquisition unit is responsible for digitizing the physical signals, acquiring in real time the instantaneous pressure signal output by the pressure sensor and the instantaneous deformation signal output by the deformation detection module. Next, the phase space modeling unit performs coordinate mapping and discrete point fitting, converting the time-domain data into a dynamic hysteresis loop model in a two-dimensional phase space. Subsequently, the energy calculation unit executes the area integral algorithm of the closed curve to accurately calculate the viscous energy loss value of this touch operation. Based on this, the waveform synthesis unit synthesizes an energy compensation waveform that can offset viscous damping based on this loss value and a preset rheological impedance model. Finally, the drive control unit includes a digital-to-analog converter and a power amplifier circuit, outputting the energy compensation waveform to the haptic feedback actuator to drive it to generate physical displacement.

[0094] This embodiment achieves closed-loop control from physical perception to model calculation to drive execution through modular system architecture design; the independent division of labor of each unit ensures efficient data flow processing, enabling the system to cope with the real-time feedback requirements under high-frequency touch operation.

[0095] The data acquisition unit includes: a pressure sensing circuit connected to the bottom of the touch panel for acquiring instantaneous pressure signals; and a capacitor plate spacing detection circuit connected to the composite structure layer of the touch panel for acquiring instantaneous deformation signals.

[0096] This embodiment further specifies the hardware implementation of the data acquisition unit; this configuration aims to achieve high-precision micro-deformation detection using the existing touch panel structure; firstly, the pressure sensing circuit adopts a piezoresistive sensor with a Wheatstone bridge structure, connected to the bottom of the touch panel, specifically for capturing minute changes in normal force and acquiring instantaneous pressure signals; simultaneously, the capacitor plate spacing detection circuit is connected to the composite structure layer of the touch panel; this circuit utilizes the principle of parasitic capacitance change between the ITO layer of the touch panel itself and the backplate of the display module; the physical model is based on the parallel plate capacitor formula. To ensure the clarity of parameter sources and the reproducibility of calculations, the system performs a benchmark calibration procedure each time it is powered on: reading the current parasitic capacitance value in a touchless state and storing it as the initial capacitance. For example, 150pF, while simultaneously reading the factory-calibrated initial electrode spacing from the OTP memory area of ​​the touch chip. For example, 0.2mm, this value is measured on the production line by a laser displacement sensor; when a finger presses, causing a slight deformation of the touch panel, the electrode spacing... Decrease, resulting in capacitance value Increase; in order to accurately inversely solve for the instantaneous deformation signal , defined as the decrease in the distance between the electrodes, i.e. The system employs a second-order Taylor series expansion algorithm for inverse solution; firstly, the distance formula is transformed into... At the initial capacitance The area unfolded, making Using approximate formulas It can be deduced that:

[0097] ;

[0098] Based on this derivation, the system sets the structural geometric coefficients. At the right time, and Negative values, obtained through the formula Perform real-time calculations; among which The measured capacitance is used; through this second-order nonlinear fitting, the system can reconstruct the instantaneous deformation signal with high linearity without the need for additional displacement sensors, effectively correcting the inverse nonlinear error between capacitance and distance.

[0099] This embodiment utilizes the inherent capacitance characteristics of the touch panel to detect deformation, achieving high-precision physical quantity acquisition without significantly increasing hardware costs and stack thickness. This innovative design, which reuses existing structures, greatly improves the feasibility and integration of the solution in mass production for consumer electronics products.

[0100] The waveform synthesis unit operates in a field-programmable gate array (FPGA) or a high-frequency microcontroller (MCU) to achieve a microsecond-level waveform synthesis response.

[0101] This embodiment is a further specification of the waveform synthesis unit computing platform; this configuration is designed to meet the stringent requirements of haptic feedback for extremely low latency; given that integration and fractional derivative calculations must be completed in an extremely short time to ensure the real-time performance of haptic feedback, general-purpose application processors have scheduling delays that cannot meet the requirements; therefore, this system deploys the waveform synthesis unit in a field-programmable gate array (FPGA) or a high-frequency microcontroller (MCU) of the Cortex-M7 level; this hardware architecture is specifically designed to perform hardware-accelerated computation, ensuring that the end-to-end response time from signal acquisition to waveform output is controlled in the microsecond range;

[0102] This embodiment resolves the conflict between complex physical model calculations and real-time haptic response by deploying a dedicated hardware acceleration unit; it ensures that even when performing fractional calculus calculations that require high computing power, it can still maintain extremely low operation latency, thereby achieving a zero-latency experience of hand-activated vibration.

[0103] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the preferred embodiments, while those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A touch force feedback simulation method based on pressure deformation signal, characterized in that, include: Configure pressure sensors and deformation detection modules to collect physical state data of the touch interface; In response to the detection of a touch operation, an impedance compensation process is triggered, the impedance compensation process including: Step 1: Acquire the instantaneous pressure signal output by the pressure sensor and the instantaneous deformation signal output by the deformation detection module; Step 2: Map the instantaneous pressure signal and instantaneous deformation signal to a two-dimensional phase space, and construct a dynamic hysteresis loop model through discrete point fitting. Step 3: Perform area integration on the dynamic hysteresis loop model to calculate the viscous energy loss value of this touch operation. Step 4: Using the fractional derivative algorithm, the instantaneous pressure signal is decomposed into elastic and viscous components; based on the viscous energy loss value, the reverse force parameter used to counteract the viscous component is calculated; according to the reverse force parameter, the preset basic waveform is pre-distorted to generate an energy compensation waveform. Step 5: Output the energy compensation waveform to the haptic feedback actuator to drive the haptic feedback actuator to generate reverse damped vibration.

2. The touch force feedback simulation method based on pressure deformation signal according to claim 1, characterized in that, Constructing a dynamic hysteresis loop model includes: Establish an energy phase plane coordinate system with pressure parameters as the vertical axis and deformation parameters as the horizontal axis; The trajectory of instantaneous pressure and instantaneous deformation signals is tracked in real time in the energy phase plane coordinate system; The changing trajectory is reconstructed using a closed curve fitting algorithm to generate a closed dynamic hysteresis loop model.

3. The touch force feedback simulation method based on pressure deformation signal according to claim 1, characterized in that, It also includes environmental adaptation modification processes: Obtain the current ambient temperature data; In step 4, the ambient temperature data is used as a correction factor to adjust the elastic modulus parameter of the rheological impedance model. Among them, the preset low temperature threshold is less than the preset high temperature threshold; If the ambient temperature data is lower than the preset low temperature threshold, increase the weight of the elastic modulus parameter; If the ambient temperature data is higher than the preset high temperature threshold, reduce the weight of the elastic modulus parameter; If the ambient temperature data is greater than or equal to the preset low temperature threshold and less than or equal to the preset high temperature threshold, the elastic modulus parameter remains unchanged.

4. The touch force feedback simulation method based on pressure deformation signal according to claim 1, characterized in that, It also includes a health monitoring process: Calculate the characteristic area of ​​the dynamic hysteresis loop model; If the feature area is greater than the preset anomaly threshold, a structural layer peeling warning signal is generated. If the feature area is less than or equal to the anomaly threshold, the current feedback strategy is maintained.

5. The touch force feedback simulation method based on pressure deformation signal according to claim 1, characterized in that, It also includes an aging calibration process: Obtain the preset baseline hysteresis loop characteristics; Periodically calculate the geometric deviation between the dynamic hysteresis loop model and the baseline hysteresis loop characteristics; The compensation coefficients of the rheological impedance model are updated based on the geometric deviation value to maintain the consistency of tactile feedback. The preset reference hysteresis loop characteristic is defined as a dimensionless reference loss factor.

6. The touch force feedback simulation method based on pressure deformation signal according to claim 1, characterized in that, The energy compensation waveform has a phase characteristic opposite to the phase lag direction of the viscous energy loss, and the energy integral value of the energy compensation waveform is equal to the viscous energy loss value.

7. A touch force feedback simulation system based on pressure deformation signals, applied to the touch force feedback simulation method based on pressure deformation signals as described in any one of claims 1-6, characterized in that, include: The data acquisition unit is used to acquire the instantaneous pressure signal output by the pressure sensor and the instantaneous deformation signal output by the deformation detection module; The phase space modeling unit is used to map instantaneous pressure signals and instantaneous deformation signals to a two-dimensional phase space, and construct a dynamic hysteresis loop model through discrete point fitting processing. The energy calculation unit is used to perform area integration on the dynamic hysteresis loop model to calculate the viscous energy loss value of this touch operation. The waveform synthesis unit uses a fractional derivative algorithm to decompose the instantaneous pressure signal into elastic and viscous components; Based on the viscous energy loss value, the parameters of the reverse force used to counteract the viscous component are calculated; Based on the reverse force parameters, the preset basic waveform is pre-distorted to generate an energy compensation waveform. The drive control unit is used to output the energy compensation waveform to the haptic feedback actuator.

8. The touch force feedback simulation system based on pressure deformation signal according to claim 7, characterized in that, The data acquisition unit includes: A pressure sensing circuit connected to the bottom of the touch panel is used to collect instantaneous pressure signals; A capacitor plate spacing detection circuit connected to the composite structure layer of the touch panel is used to collect instantaneous deformation signals.

9. The touch force feedback simulation system based on pressure deformation signal according to claim 7, characterized in that, The waveform synthesis unit operates in a field-programmable gate array (FPGA) or a high-frequency microcontroller (MCU) to achieve a microsecond-level waveform synthesis response.

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