Suspension piezoelectric steering wheel key device and blind operation switch control method thereof, vehicle

Abstract

The application discloses a kind of suspension piezoelectric steering wheel button device and its blind operation switch control method, vehicle, it is related to the field of automobile man-machine interaction, the device includes base and controller;Multiple layer composite suspension cover plate assembly is installed on base, multiple layer composite suspension cover plate assembly includes from top to bottom, from outside to inside, mutually adhered touch surface, decorative film layer, metal substrate in sequence;Capacitance sensing element is adhered to the back of decorative film layer, and capacitance sensing element is used to detect the coordinate position of finger on touch surface;Capacitance sensing element is adhered to the back of decorative film layer, and capacitance sensing element is used to detect the coordinate position of finger on touch surface;Metal substrate back adheres piezoelectric element, piezoelectric element detects the pressing pressure value of finger to touch surface using positive piezoelectric effect and is transmitted to controller, and generates tactile feedback vibration using inverse piezoelectric effect;Metal substrate has high elastic modulus, as the resonance cavity of piezoelectric element, for transmitting the vibration generated by piezoelectric element to touch surface;Controller is used to drive piezoelectric element to output tactile feedback signal according to finger coordinate position and pressing pressure value.

Description

Technical Field

[0001] This invention relates to the field of automotive human-machine interaction technology, and in particular to a floating piezoelectric steering wheel button device and its blind operation switch control method, and a vehicle. Background Technology

[0002] With the development of automotive intelligence, traditional physical buttons on steering wheels are gradually being replaced by capacitive touch switches due to their large number and complex layout. Capacitive touch switches achieve operation through touch sensing technology, improving the convenience and technological feel of operation to a certain extent. Currently, haptic feedback is typically achieved by combining a capacitive touch panel with an eccentric rotor motor (ERM) or a linear motor (LRA). The capacitive touch panel detects the touch position of the finger, and when a touch operation is detected, it drives the ERM or LRA to generate vibration feedback, providing the user with an operation confirmation signal. However, in this design, the capacitive touch panel has a completely flat structure. Without looking down at the steering wheel, the driver cannot perceive the specific location and boundaries of the buttons, which can easily lead to accidental touches or safety hazards caused by a shift in gaze. Furthermore, the eccentric rotor motor and linear motor have large vibration start-stop inertia, resulting in a delayed feedback response and making it difficult to simulate the crisp tactile feedback of real physical buttons, leading to a poor user experience. Summary of the Invention

[0003] This invention provides a floating piezoelectric steering wheel button device and its blind operation switch control method and vehicle, solving the problems of existing steering wheel touch switches that cannot be blindly operated, have a high rate of accidental touches, and have unrealistic tactile feedback, thus affecting the driver's driving safety and operating experience.

[0004] In a first aspect, the present invention provides a floating piezoelectric steering wheel button device.

[0005] A suspended piezoelectric steering wheel button device includes a base and a controller; The base is equipped with a multi-layer composite floating cover assembly, which includes, from top to bottom and from outside to inside, a touch surface that is bonded to each other, a decorative film layer, and a metal substrate. A capacitive sensing element is attached to the back of the decorative film layer, which is used to detect the coordinate position of the finger on the touch surface; a piezoelectric element is attached to the back of the metal substrate, which uses the direct piezoelectric effect to detect the pressure value of the finger on the touch surface and transmits it to the controller, and uses the inverse piezoelectric effect to generate tactile feedback vibration; the metal substrate has a high elastic modulus and serves as a resonant cavity for the piezoelectric element, which is used to transmit the vibration generated by the piezoelectric element to the touch surface; The controller is used to drive the piezoelectric element to output a tactile feedback signal based on the finger coordinate position and the pressing pressure value.

[0006] A further technical solution is provided where a vertical pressing stroke is reserved between the base and the multi-layer composite floating cover assembly, and an elastic floating support structure is provided between the two. The multi-layer composite floating cover is suspended and installed on the base through the elastic floating support structure; the vertical pressing stroke is 0.10mm~0.20mm. The elastic suspension support structure is a silicone sealing ring distributed along the peripheral edge of the multi-layer composite suspension cover assembly, and the elastic deformation direction of the elastic suspension support structure is orthogonal to the propagation direction of the high-frequency vibration of the piezoelectric element.

[0007] A further technical solution is that the base is provided with a labyrinth-style waterproof structure around its perimeter. The labyrinth-style waterproof structure includes waterproof ribs and water-guiding grooves, forming a non-contact hydrophobic channel. The labyrinth-style waterproof structure works in conjunction with the elastic suspension support structure to allow vertical displacement of the multi-layer composite suspension cover assembly while preventing liquid from entering the interior of the base.

[0008] In a further technical solution, the touch surface is optical glass or crystal glass; the metal substrate is made of stainless steel. The decorative film layer is an IML film or an INS film, used to realize the functions of graphic printing carrier, explosion-proof backing and visual enhancement; the visual enhancement function is achieved by using the optical thickness between the decorative film layer and the touch surface to form an icon, which is visually suspended inside the touch surface.

[0009] In a further technical solution, the capacitive sensing element is a capacitor electrode, which is attached to the hollowed-out area on the back of the decorative film layer and the metal substrate; the piezoelectric element is a multi-layer stacked piezoelectric ceramic, which is bonded and fixed to the central area on the back of the metal substrate by high-strength epoxy resin adhesive, and the piezoelectric element also serves as a pressure sensor and a tactile output actuator.

[0010] Secondly, the present invention provides a blind operation switch control method for a floating piezoelectric steering wheel button device.

[0011] A blind operation switch control method for a floating piezoelectric steering wheel button device, comprising a two-stage interactive logic of guided search and trigger confirmation executed by a controller, including: Acquire the coordinate position information of the finger on the touch surface and the pressing pressure value of the finger on the touch surface; If the pressing pressure value is within the first threshold range, then the piezoelectric element is driven to output continuous micro-vibration according to the finger coordinate position, generating a perceptible vibration sensation in the button boundary area of ​​the touch surface, guiding the finger to locate the target button. If the finger has moved to a preset position, then it is determined whether the pressing pressure value exceeds a second threshold. If so, the continuous micro-vibration is interrupted, and the piezoelectric element is driven to output a single-pulse transient strong vibration to simulate the click sensation of a mechanical button and provide a feedback operation confirmation signal.

[0012] A further technical solution is that the first threshold range is 0.5N~2.0N, and the second threshold is greater than 4.0N; the driving frequency of the continuous micro-vibration is 200Hz~300Hz, and the amplitude is 20Vpp; the single-pulse transient strong vibration is a single-pulse sine wave with a half wavelength of 10ms~15ms and an amplitude of 110V, so that the touch surface generates a transient acceleration of not less than 15G.

[0013] A further technical solution involves obtaining the pressure value of a finger pressing on the touch surface, including the following steps: The piezoelectric element also functions as a pressure sensor. A sampling time window is inserted at the end of each driving cycle of the piezoelectric element. During the sampling time window, the output of the driving signal to the piezoelectric element is paused and the positive piezoelectric output voltage of the piezoelectric element is sampled. The sampled values ​​of multiple sampling time windows are filtered to obtain the pressing pressure value.

[0014] Further technical solutions also include: The background signal of the piezoelectric element sensing channel is continuously monitored without active operation, and the root mean square value of the background signal within a preset time window is used as a quantitative index of road vibration intensity. The first threshold range and the second threshold are dynamically adjusted according to the road vibration intensity, and the pressing pressure value is subjected to low-frequency noise filtering to ensure that the pressure range between the first threshold range and the second threshold is always not less than the preset minimum distance.

[0015] Thirdly, the present invention also provides a vehicle.

[0016] A vehicle includes a steering wheel, on which the aforementioned floating piezoelectric steering wheel button device is provided, or a blind operation switch control method for performing the aforementioned floating piezoelectric steering wheel button device.

[0017] The above one or more technical solutions have the following beneficial effects: This invention provides a floating piezoelectric steering wheel button device, its blind operation switch control method, and a vehicle. The specific structure of the steering wheel button device is optimized: tactile feedback is generated using the inverse piezoelectric effect of piezoelectric elements. Compared to traditional eccentric rotor motors and linear motors, piezoelectric elements have a faster response speed and lower start-stop inertia, enabling low-latency, high-fidelity tactile feedback. Single-pulse transient strong vibrations can simulate the crisp click of mechanical buttons, significantly improving the user experience. Furthermore, a corresponding blind operation switch interaction method is designed for this button structure: through two-stage pressure threshold control combined with finger coordinate position mapping, the piezoelectric element drive waveform is adjusted in real time according to the finger position during the blind operation guidance stage, generating a perceptible vibration tactile sensation in the button boundary area. This allows the driver to identify the button position and boundary by fingertip touch without looking down, achieving true blind operation and eliminating the accidental touch problem of flat touch panels, greatly improving driving safety. In addition, the floating piezoelectric steering wheel button device proposed in this invention also achieves non-contact waterproof sealing while ensuring the vertical pressing stroke through a multi-layer composite floating cover structure combined with a labyrinth waterproof structure, meeting automotive-grade waterproof and dustproof requirements, while eliminating structural noise during pressing, thus improving the reliability and durability of the product.

[0018] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is an exploded view of the overall structure of the suspended piezoelectric steering wheel button device provided in an embodiment of the present invention; Figure 2 A circuit hardware architecture block diagram of a floating piezoelectric steering wheel button device provided in an embodiment of the present invention; Figure 3 A flowchart of a blind operation switch control method for a floating piezoelectric steering wheel button device provided in an embodiment of the present invention; Figure 4 The diagram shows a comparison of two-stage tactile feedback drive waveforms provided in the embodiments of the present invention; wherein, (a) is a continuous micro-vibration waveform in the blind operation guidance mode, and (b) is a single-pulse transient strong vibration waveform in the trigger confirmation mode.

[0021] The components include: 1. Touch surface; 2. Decorative film layer; 3. Metal substrate; 4. Piezoelectric element; 5. Silicone sealing ring; 6. Base; 7. Labyrinth waterproof structure. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are exemplary and are intended only to describe specific embodiments and to provide further explanation of the invention, and are not intended to limit the scope of exemplary embodiments of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] As noted in the background section, traditional physical buttons on steering wheels are gradually being replaced by capacitive touch switches. Existing steering wheel touch switches typically use a capacitive touch panel combined with an eccentric rotor motor (ERM) or a linear motor (LRA) to provide haptic feedback. The capacitive touch panel detects the touch position of a finger, and upon detecting a touch operation, drives the ERM or LRA to generate vibration feedback, providing the user with an operation confirmation signal. However, the existing capacitive touch switch method for steering wheels has significant drawbacks: the capacitive touch panel has a completely flat structure, and without the driver looking down at the steering wheel, the fingers cannot perceive the specific location and boundaries of the buttons, which can easily lead to accidental touches or safety hazards caused by a shift in gaze, and lacks a sense of boundaries for blind operation; the eccentric rotor motor and linear motor have large vibration start-stop inertia, resulting in a delayed feedback response, failing to simulate the crisp tactile feedback of real physical buttons, and resulting in a poor user experience.

[0024] To address the aforementioned issues, this invention proposes a floating piezoelectric steering wheel button device and its blind operation switch control method and vehicle. Through a multi-layer composite floating cover structure and a two-stage control design using piezoelectric elements, effective blind operation switch control and timely feedback of the steering wheel buttons are achieved, thereby improving driver safety and operating experience. Specifically, in this invention, a multi-layer composite suspended cover assembly is used as the user interface. This assembly includes, from top to bottom and from outside to inside, a touch surface, a decorative film layer, and a metal substrate that are bonded together. The metal substrate serves as the resonant cavity for the piezoelectric element, transmitting the vibrations generated by the piezoelectric element to the touch surface with high fidelity. The piezoelectric element also functions as a pressure sensor and a tactile output actuator, using the direct piezoelectric effect to detect the pressure value of the finger pressing the touch surface and using the inverse piezoelectric effect to generate tactile feedback vibration. The controller executes a two-stage pressure threshold control logic. When the finger pressing pressure value is within the first threshold range, the piezoelectric element is driven to output continuous micro-vibration according to the finger's coordinate position, generating a perceptible tactile vibration in the button boundary area of ​​the touch surface, guiding the finger to locate the target button and achieving blind operation guidance. When the finger moves to a preset position and the pressing pressure value exceeds the second threshold, the continuous micro-vibration is interrupted, and the piezoelectric element is driven to output a single-pulse transient strong vibration to simulate the click of a mechanical button, providing a feedback operation confirmation signal and achieving trigger confirmation. Through the above technical solution, the present invention realizes a complete interactive closed loop of blind operation guidance and operation confirmation, makes up for the shortcomings of the prior art, and improves driving safety and operating experience.

[0025] The example environment in which the various embodiments of the present invention can be implemented includes a steering wheel, a driver, and an in-vehicle controller. The steering wheel, as a user device, is equipped with the floating piezoelectric steering wheel button device of the present invention. This device includes a multi-layer composite floating cover assembly, a piezoelectric element, a capacitive sensing element, and a base, for receiving touch and press operations from the driver. The driver, as a user, can blindly operate the buttons on the steering wheel using fingertip touch during driving, completing button positioning and operation confirmation without looking down. The in-vehicle controller, as a computing device, is based on an automotive-grade MCU and drives the piezoelectric element through a dedicated piezoelectric drive chip. It receives coordinate data from the capacitive sensing element and pressure data from the piezoelectric element in real time, executes two-stage interaction logic, and drives the piezoelectric element to output corresponding tactile feedback signals based on the finger coordinate position and pressing pressure value.

[0026] Furthermore, the piezoelectric element is connected to the vehicle controller via a dedicated piezoelectric driver chip. This chip incorporates a boost circuit to increase the vehicle's 12V power supply to 100V~120V, driving the piezoelectric element to deform. Simultaneously, the chip's internal high-precision ADC collects the positive piezoelectric output voltage of the element in real time, obtaining the finger pressure value. The capacitive sensing element is connected to the vehicle controller via a flexible printed circuit (FPC) to transmit the X / Y axis coordinate position information of the finger on the touch surface in real time. It should be noted that the data collection and processing in this embodiment strictly adheres to relevant laws and regulations. The collected finger coordinate position and pressure data are used solely for implementing blind operation switch control functions and are not used for any other unauthorized purposes.

[0027] It should be understood that the example environment is described for illustrative purposes only and does not imply any limitation on the scope of protection of the present invention. The present invention can also be applied to other intelligent interaction scenarios, and the environment may also include components such as sensors and communication modules not shown.

[0028] Example 1 This embodiment provides a floating piezoelectric steering wheel button device, which mainly includes a base and a controller (not shown in the figure). The components of the device and their working principle are described in detail below.

[0029] like Figure 1 As shown, a multi-layer composite floating cover assembly is installed on the base 6. The multi-layer composite floating cover assembly includes, from top to bottom and from outside to inside, a touch surface 1 (or touch cover), a decorative film layer 2, and a metal substrate 3 that are attached to each other. The touch surface is located on the outermost layer and is the user-touchable surface of the device. In some embodiments, it is made of optical glass or crystal glass with a thickness of approximately 1.5mm to 2.0mm. It has high light transmittance, high hardness, good wear resistance, and excellent tactile feel, providing users with a direct tactile interaction interface and excellent tactile and visual effects. The decorative film layer is a functional film located between the touch surface and the metal substrate. In some embodiments, it is an IML film (in-mold label film) or an INS film (in-mold insert film). It is tightly bonded to the touch surface and the metal substrate through a full-lamination process (Optical Bonding) to ensure no air bubbles between layers and high-fidelity vibration transmission. This decorative film layer simultaneously serves as a graphic printing carrier, an explosion-proof backing, and a visual enhancement. The metal substrate is located on the innermost layer and is made of SUS304 stainless steel in some embodiments, serving as the structural framework of the multi-layer composite suspended cover assembly.

[0030] As one implementation method, the decorative film layer uses a high-toughness IML (or INS) decorative film, which has a triple function: 1) Graphic printing carrier function: The decorative film layer carries high-precision translucent characters and light-blocking ink to display the icons and text of the buttons. Because the decorative film layer is a flexible film, printing on it offers higher yield and finer pattern resolution compared to printing directly on the back of irregularly shaped thick-walled covers. 2) Explosion-proof backing function: When the touch surface is broken due to a violent impact, the decorative film layer uses its toughness to absorb the fragments of the touch surface, preventing the fragments from flying and causing secondary injury to the driver, which meets the requirements of GB 11552 internal protrusion regulations. 3) Visual Enhancement Function: The visual enhancement function utilizes the optical thickness between the decorative film layer and the touch surface to create the visual effect of icons floating inside the touch surface. Specifically, due to the certain optical thickness (usually 1.5mm~2.0mm) between the decorative film layer and the touch surface, when light passes through the touch surface and shines on the icon on the decorative film layer, due to optical refraction and scattering effects, a deep 3D texture is visually created, making the icon appear to float inside the touch surface, significantly enhancing the product's premium and technological feel.

[0031] In one implementation, the metal substrate has a high elastic modulus. Besides serving as a structural framework, it also acts as a resonant cavity for the piezoelectric element, transmitting the vibrations generated by the element to the touch surface. Specifically, when the piezoelectric element deforms under the drive of the controller, this deformation is transmitted through the metal substrate to the decorative film layer and the touch surface. Due to the high elastic modulus of the metal substrate, the vibration energy is transmitted to the touch surface almost without loss, causing the touch surface to vibrate in accordance with the driving waveform of the piezoelectric element. Compared to traditional plastic frameworks, the high elastic modulus of the metal substrate significantly improves vibration transmission efficiency, ensuring high fidelity of tactile feedback. Furthermore, the stainless steel metal substrate possesses high elastic modulus and strong corrosion resistance, enabling it to maintain stable vibration transmission performance over a long period.

[0032] A capacitive sensing element is attached to the back of the aforementioned decorative film layer. This element detects the coordinate position of a finger on the touch surface. In some embodiments, the capacitive sensing element is a capacitor electrode integrated onto a flexible printed circuit board (FPC) and attached to the cutout area where the decorative film layer meets the metal substrate, thereby reducing the influence of the stainless steel substrate on the capacitive signal. Preferably, the cutout of the metal substrate is such that the central area of ​​the corresponding button area remains solid, while the surrounding area has slots or several through holes. The capacitor electrode is embedded in this cutout area, and can directly or indirectly (e.g., through differential signals or four-point touch sensing) detect the coordinates of the entire area. When the driver's finger touches or approaches the touch surface, capacitive coupling is formed between the finger and the capacitor electrode. The capacitor electrode detects the change in capacitance and transmits the X / Y axis two-dimensional coordinate position information of the finger on the touch surface to the controller via the FPC. The controller receives the finger coordinate position information in real time to determine which area of ​​the button the finger is currently located in (e.g., the center area or the boundary area of ​​the button), and adjusts the driving waveform of the piezoelectric element in real time according to the finger coordinate position.

[0033] A piezoelectric element 4 is attached to the back of the aforementioned metal substrate. The piezoelectric element uses the direct piezoelectric effect to detect the pressure value of a finger pressing on the touch surface and transmits it to the controller, and uses the inverse piezoelectric effect to generate tactile feedback vibration. In some embodiments, the piezoelectric element is a multilayer stacked piezoelectric ceramic (PZT), which is bonded to the central area of ​​the back of the metal substrate (i.e., the central area of ​​the corresponding button) with high-strength epoxy resin adhesive. The pressure sensing is uniform and the vibration can be transmitted to the entire touch surface through the resonant cavity of the metal substrate. This piezoelectric element also serves as a pressure sensor and a tactile output actuator.

[0034] The working principle of the positive piezoelectric effect is as follows: When the driver's finger presses the touch surface, the pressure of the touch surface and the decorative film layer is transmitted to the metal substrate, causing a slight deformation of the metal substrate, which in turn causes the piezoelectric element attached to the back of the metal substrate to deform. Under the action of deformation, the piezoelectric element generates a voltage signal proportional to the pressure. This voltage signal is acquired in real time by a high-precision ADC inside a dedicated piezoelectric driver chip. After being processed by an algorithm, the pressing pressure value of the finger on the touch surface is obtained and transmitted to the controller. The controller determines whether the finger is currently in the blind operation guidance stage (the pressing pressure value is within the first threshold range) or the trigger confirmation stage (the pressing pressure value exceeds the second threshold) based on the pressing pressure value.

[0035] The working principle of the inverse piezoelectric effect is as follows: The controller applies a driving voltage to the piezoelectric element through a dedicated piezoelectric drive chip, causing the piezoelectric element to deform under the action of the driving voltage. This deformation is transmitted to the decorative film layer and the touch surface through the metal substrate, causing the touch surface to vibrate. Depending on the frequency, amplitude, and waveform of the driving voltage, the touch surface produces different types of vibrations, thereby achieving different tactile feedback effects. For example, when the controller applies a continuous driving voltage of 200Hz~300Hz with an amplitude of 20Vpp, the piezoelectric element produces continuous micro-vibrations, and the touch surface produces high-frequency micro-vibrations, forming a dynamic air film between the finger and the touch surface, changing the coefficient of friction, and making the fingertip produce a perceptible boundary touch. When the controller applies a single-pulse sine wave driving voltage of half wavelength 10ms~15ms with an amplitude of 110V, the piezoelectric element produces a single-pulse transient strong vibration, and the touch surface produces a transient acceleration of no less than 15G, simulating the click sensation of a mechanical button.

[0036] In some embodiments, a vertical pressing stroke is provided between the base and the multi-layer composite floating cover assembly, and an elastic floating support structure is provided between them. The multi-layer composite floating cover is suspended and installed on the base by the elastic floating support structure. In this embodiment, the elastic floating support structure is a silicone sealing ring 5 distributed along the peripheral edge of the multi-layer composite floating cover assembly; as another embodiment, the elastic floating support structure can also be implemented using spring sheets or the like.

[0037] The elastic deformation direction of the elastic suspension support structure is orthogonal to the propagation direction of the high-frequency vibration of the piezoelectric element, with a vertical pressing stroke of 0.10mm~0.20mm, preferably with a 0.15mm allowance. Specifically, silicone sealing rings are distributed along the peripheral edge of the multi-layer composite suspension cover assembly, flexibly connecting the cover assembly to the base. When the driver presses the touch surface with their finger, the multi-layer composite suspension cover assembly moves downward as a whole under the pressing pressure, and the silicone sealing rings undergo elastic deformation in the vertical direction (Z-axis), allowing the cover assembly to produce a vertical displacement of 0.10mm~0.20mm. This vertical pressing stroke provides the driver with clear pressing feedback, enhancing the sense of operation confirmation.

[0038] It should be noted that the elastic deformation direction of the silicone sealing ring is vertical (Z-axis), while the high-frequency vibration generated by the piezoelectric element mainly propagates along the plane of the metal substrate in the horizontal direction (XY plane). Since these directions are orthogonal, the damping effect of the silicone sealing ring has minimal impact on the in-plane propagation of the high-frequency vibration of the piezoelectric element and will not cause a significant attenuation of the vibration amplitude required for the extrusion film effect. Furthermore, the low stiffness of the silicone sealing ring helps to create vibration isolation between the multi-layer composite suspended cover assembly and the base in the high-frequency vibration direction, reducing the energy loss from vibration to the base and thus improving the effective vibration amplitude of the touch surface.

[0039] Furthermore, considering that ordinary injection-molded touch panels lack effective suspension and waterproof design, are prone to structural noise when pressed, and cannot meet the stringent automotive-grade waterproof and dustproof requirements, affecting product reliability and durability, this embodiment also includes a labyrinth-style waterproof structure 7 around the base. This labyrinth-style waterproof structure includes waterproof ribs and water-guiding channels, forming a non-contact hydrophobic channel. The labyrinth-style waterproof structure works in conjunction with the elastic suspension support structure to allow vertical displacement of the multi-layer composite suspension cover assembly while preventing liquid from entering the base.

[0040] Specifically, the base features a labyrinthine structure around its perimeter, consisting of waterproof ribs and water-guiding channels. The waterproof ribs extend upwards along the base's perimeter, maintaining a slight gap with the perimeter of the multi-layer composite suspended cover assembly, forming a non-contact waterproof barrier. The water-guiding channels are located between the waterproof ribs, creating a meandering drainage path. When liquids (such as rainwater or beverages) splash onto the steering wheel button surface, the liquid flows along the perimeter of the multi-layer composite suspended cover assembly into the labyrinthine waterproof structure. Guided by the waterproof ribs, it flows in a meandering pattern along the water-guiding channels, ultimately exiting from the channel outlets without entering the base's internal circuitry.

[0041] Because the labyrinthine waterproof structure employs a non-contact design, the waterproof ribs and the multi-layer composite suspended cover assembly do not directly contact each other. Therefore, while allowing for a vertical displacement of 0.10mm to 0.20mm in the cover assembly, no mechanical friction or abnormal noise is generated. Simultaneously, the non-contact design avoids the degradation of waterproof performance due to friction and wear after long-term use, ensuring the long-term reliability of the device.

[0042] In this embodiment, the controller drives the piezoelectric element to output a tactile feedback signal based on the finger's coordinate position and the pressure value. The controller is based on an automotive-grade MCU (such as CVM0128) and drives the piezoelectric element through a dedicated piezoelectric driver chip (such as AWP1923). This dedicated piezoelectric driver chip has a built-in boost circuit that boosts the vehicle's 12V power supply to 100V~120V to provide the driving voltage for the piezoelectric element. Simultaneously, the high-precision ADC inside the dedicated piezoelectric driver chip collects the positive piezoelectric output voltage of the piezoelectric element in real time to obtain the finger pressure value.

[0043] Specifically, the controller receives finger coordinate position information from the capacitive sensing element and pressure value from the dedicated piezoelectric drive chip in real time, and determines the appropriate tactile feedback signal to output based on two-stage control logic. When the finger pressure value is within the first threshold range, the controller adjusts the drive waveform in real time according to the finger's coordinate position: when the finger is in the button boundary area, the controller drives the piezoelectric element to output continuous micro-vibration; when the finger is in the center area of ​​the button, the controller drives the piezoelectric element to output silent or weak waveform. When the finger moves to a preset position and the pressure value exceeds the second threshold, the controller immediately interrupts the continuous micro-vibration and drives the piezoelectric element to output a single-pulse transient strong vibration.

[0044] Combination Figure 2 As shown, the circuit hardware architecture and control process of the floating piezoelectric steering wheel button device provided in this embodiment are described in more detail. The figure fully illustrates the signal interaction relationship and power supply path between the controller (MCU), dedicated piezoelectric drive chip, capacitive sensing element and piezoelectric element (PZT), wherein: 1) The vehicle-mounted 12V DC power supply serves as the energy source for the entire system, supplying power to each module via two paths. The first path, after being stepped down and regulated by an LDO (Low Dropout Linear Regulator) or PMIC (Power Management Integrated Circuit), provides a stable 3.3V or 5V operating power to the automotive-grade MCU (in some embodiments, model CVM0128), ensuring reliable operation of the MCU under the wide temperature and voltage environment of the vehicle. The second path directly supplies power to a dedicated piezoelectric driver chip (in some embodiments, model AWP1923). The Boost converter built into the piezoelectric driver chip boosts the 12V power supply to 100V~120V, providing a high-voltage drive power to the piezoelectric element (PZT piezoelectric ceramic). This boost design is key to achieving a large deformation of the piezoelectric element. The deformation of the piezoelectric ceramic is positively correlated with the applied voltage. A drive voltage of 100V to 120V enables the piezoelectric element to generate sufficient deformation amplitude, thereby driving the metal substrate and touch surface to produce perceptible vibrations.

[0045] 2) The MCU and the dedicated piezoelectric driver chip communicate bidirectionally via SPI or I2C bus, transmitting the following four types of signals: First, control signals: the MCU sends control parameters such as drive enable, drive frequency, and drive amplitude to the piezoelectric driver chip via SPI / I2C bus to precisely configure the output waveform of the piezoelectric element; Second, virtual texture waveform control commands: in blind operation guidance mode, the MCU controls the output waveform of the piezoelectric element based on the finger coordinate position (X, Y) Real-time calculation of the continuous micro-vibration waveform parameters to be output (frequency 200Hz to 300Hz, amplitude 20Vpp), and sending the waveform control command to the piezoelectric driver chip via the bus. The driver chip adjusts the high-voltage drive waveform output to the PZT in real time. Third, tactile feedback trigger command: In trigger confirmation mode, the MCU sends a single-pulse trigger command to the piezoelectric driver chip. The driver chip immediately outputs a single-pulse sine wave with a half wavelength of 10ms to 15ms and an amplitude of 110V to the PZT, producing a crisp click-like feel. Fourth, pressure data feedback: The piezoelectric driver chip has a built-in high-precision ADC that collects the positive piezoelectric output voltage of the PZT within the sampling time window at the end of each drive cycle. After analog-to-digital conversion, the pressure data is fed back to the MCU via the SPI / I2C bus. The MCU uses this data to calculate the pressing pressure value and determine the threshold.

[0046] 3) The capacitive sensing element (capacitor plates, integrated on the FPC flexible circuit board) is directly connected to the MCU via the FPC flexible circuit board, transmitting the X / Y axis two-dimensional coordinate position information of the finger on the touch surface to the MCU in real time. The capacitive sensing element adopts the mutual capacitance or self-capacitance detection principle. When the finger touches or approaches the touch surface, capacitive coupling is formed between the finger and the capacitor plates. By scanning and calculating the capacitance values ​​of each capacitor plate, the coordinate position (X, Y) of the finger is obtained. The MCU polls the coordinate data of the capacitive sensing element at a high frequency (usually 100Hz~200Hz) to ensure the real-time nature of the finger position information, providing accurate input for the judgment of the button boundary area in the blind operation guidance mode.

[0047] 4) A bidirectional signal flow exists between the piezoelectric element (PZT piezoelectric ceramic assembly) and the dedicated piezoelectric drive chip. This is the core circuit foundation for the time-division multiplexing of the piezoelectric element in this solution. Forward (driving direction): The piezoelectric drive chip applies a boosted 100V~120V high-voltage AC drive signal to the two electrodes of the PZT. Under the inverse piezoelectric effect, the PZT deforms, driving the metal substrate and touch surface to vibrate, outputting tactile feedback. Reverse (sensing direction): At the end of each driving cycle, within the sampling time window, the piezoelectric drive chip turns off the high-voltage drive output. Under the pressure of a finger, the PZT generates a positive piezoelectric effect, and its two electrodes generate a voltage signal proportional to the pressing pressure. This signal is acquired by the high-precision ADC built into the piezoelectric drive chip, converted from analog to digital, and then transmitted back to the MCU as pressure data. Through precise timing control of the above bidirectional signal flow, the PZT achieves time-division multiplexing of the drive actuator and pressure sensor on the same physical device, eliminating the need for an additional independent pressure sensor, simplifying the hardware architecture, and reducing system cost and device size.

[0048] comprehensive Figure 2 The overall signal flow shown in this embodiment is as follows: 12V vehicle power supply → LDO / PMIC → MCU (digital processing core); 12V vehicle power supply → piezoelectric drive chip (Boost to 100V~120V) → PZT (high voltage drive, inverse piezoelectric effect, tactile output); PZT (direct piezoelectric effect, pressure detection) → piezoelectric drive chip (high-precision ADC sampling) → MCU (pressure data, threshold judgment); capacitive sensing element (FPC) → MCU (coordinate data, position judgment); MCU → piezoelectric drive chip (SPI / I2C, waveform control command). The above signal links form a complete closed-loop control system: the MCU acquires the finger coordinate position and pressure value in real time, and sends corresponding waveform control commands to the piezoelectric drive chip according to the two-stage control logic. The piezoelectric drive chip drives the PZT to output corresponding tactile feedback, and simultaneously collects the pressure signal from the PZT and sends it back to the MCU, realizing the closed-loop integration of perception and execution. The above architecture makes full use of the dual characteristics of the positive and negative piezoelectric effects of piezoelectric elements, and achieves complete tactile interaction functions of blind operation guidance and operation confirmation while minimizing hardware complexity.

[0049] Through the above structural design, the floating piezoelectric steering wheel button device provided in this embodiment realizes the collaborative work of the multi-layer composite floating cover plate assembly and the piezoelectric element, providing the driver with a complete tactile feedback experience for blind operation guidance and operation confirmation. At the same time, through the synergistic cooperation of the labyrinth waterproof structure and the elastic floating support structure, the waterproof performance and long-term reliability of the device are ensured.

[0050] Example 2 This embodiment provides a blind operation switch control method for a floating piezoelectric steering wheel button device, based on the floating piezoelectric steering wheel button device provided in Embodiment 1 above. The controller executes a two-stage interactive logic of guided search and trigger confirmation. Combined with... Figure 3 As shown, the steps of this method are described in detail below: Step S101: Obtain the coordinate position information of the finger on the touch surface and the pressing pressure value of the finger on the touch surface.

[0051] The aforementioned coordinate position information refers to the two-dimensional coordinates of the finger on the touch surface along the X / Y axes, which are detected in real time by the capacitive sensing element; the aforementioned pressing pressure value refers to the normal pressure applied by the finger to the touch surface, which is detected by the piezoelectric element through the positive piezoelectric effect.

[0052] Specifically, when the driver's finger touches or approaches the touch surface, the capacitive sensing element detects the change in capacitive coupling between the finger and the capacitive electrode. The two-dimensional coordinate position information (X, Y) of the finger on the touch surface is transmitted to the controller through the FPC flexible circuit board. At the same time, when the finger presses the touch surface, the pressure of the touch surface and the decorative film layer is transmitted to the metal substrate. The metal substrate undergoes a slight deformation, which causes the piezoelectric element attached to the back of the metal substrate to deform. Under the action of deformation, the piezoelectric element generates a voltage signal proportional to the pressure.

[0053] In some embodiments, the piezoelectric element also functions as a pressure sensor. A sampling time window is inserted at the end of each drive cycle of the piezoelectric element. During this window, the drive signal output to the piezoelectric element is paused, and the positive piezoelectric output voltage is sampled. The sampled values ​​from multiple sampling time windows are filtered to obtain the pressing pressure value. Specifically, at a drive frequency of 200Hz~300Hz, each vibration cycle is approximately 3.3ms~5ms. The controller, through precise timing control, inserts a drive silence window of approximately 0.3ms~0.5ms at the end of each cycle. During this window, the inverse piezoelectric drive circuit is completely shut off, and the ADC of the dedicated piezoelectric drive chip is triggered to sample the positive piezoelectric output voltage of the piezoelectric element. Drive is resumed immediately after sampling. By performing a moving average filter on the sampled values ​​from multiple consecutive sampling windows, glitches and interference introduced by residual coupling in the drive circuit are eliminated, ultimately obtaining a reliable pressing pressure value. The sampling frequency of this scheme is the drive frequency, i.e., 200~300 times per second, which fully meets the response speed requirements of real-time pressure monitoring.

[0054] Finally, the real-time output of the finger coordinate position (X, Y) and pressing pressure value P is transmitted to the controller for threshold judgment.

[0055] In this way, the time-division multiplexing mechanism of piezoelectric elements does not require the addition of additional sensor elements. While maintaining the original architecture of piezoelectric elements serving as both pressure sensors and tactile output actuators, the problem of interference between the inverse piezoelectric drive signal and the positive piezoelectric sensing signal is solved through hardware and software co-design. This enables the real-time and accurate acquisition of finger coordinate position and pressing pressure value, providing reliable input data for the subsequent two-stage interaction logic.

[0056] Step S102: Determine whether the pressing pressure value is within the first threshold range. If so, drive the piezoelectric element to output continuous micro-vibration according to the finger coordinate position, generate a perceptible vibration sensation in the button boundary area of ​​the touch surface, and guide the finger to locate the target button.

[0057] The aforementioned first threshold range is the range of pressing pressure that triggers the blind operation guidance mode; continuous micro-vibration is a continuous output of high-frequency micro-amplitude vibration, used to generate a perceptible tactile vibration in the button boundary area.

[0058] Specifically, after receiving the finger pressure value P, the controller first determines whether P is within a first threshold range. In some embodiments, the first threshold range is 0.5N to 2.0N. If P is within the first threshold range, it indicates that the driver's finger is in a light touch state, and the system enters the blind operation guidance mode.

[0059] In blind operation guidance mode, the controller adjusts the driving waveform of the piezoelectric element in real time according to the finger's coordinate position (X, Y). Specifically, the controller pre-stores the boundary area coordinate range and center area coordinate range of each button. When the finger's coordinate position (X, Y) is located in the button's boundary area, the controller drives the piezoelectric element to output continuous micro-vibration. In some embodiments, the driving frequency of the continuous micro-vibration is 200Hz~300Hz, and the amplitude is 20Vpp. Under the action of this driving waveform, the piezoelectric element generates continuous high-frequency micro-amplitude deformation, which is transmitted to the touch surface through the metal substrate, causing the touch surface to generate high-frequency micro-amplitude vibration.

[0060] like Figure 4 As shown in (a), the waveform of the continuous micro-vibration is a high-frequency sine wave or square wave with a continuous amplitude of 200Hz~300Hz and an amplitude of 20Vpp. This high-frequency micro-vibration generates a squeezing film effect between the finger and the touch surface, that is, a dynamic air film is formed between the finger and the touch surface, causing a change in the coefficient of friction, thereby producing a perceptible boundary tactile sensation at the fingertip. The driver can clearly perceive the boundary position of the button through the fingertip tactile sensation and locate the target button without looking down.

[0061] When the finger's coordinate position (X, Y) is located in the center area of ​​the button, the controller drives the piezoelectric element to output a silent or weak waveform to simulate a smooth surface, making the driver's fingertip feel smooth. This contrasts with the vibration sensation at the button's boundary area, further enhancing the perceptibility of the button's boundary.

[0062] In some embodiments, the background signal of the piezoelectric element sensing channel is continuously monitored in the absence of active operation, and the root mean square value of the background signal within a preset time window is used as a quantitative indicator of the road vibration intensity; the first threshold interval and the second threshold are dynamically adjusted according to the road vibration intensity, and the pressing pressure value is subjected to low-frequency noise filtering processing, so that the pressure interval between the first threshold interval and the second threshold is always not less than the preset minimum distance.

[0063] Specifically, when a vehicle is traveling on a bumpy road, road vibrations are transmitted to the driver's fingers via the steering wheel. This may cause fluctuations in contact pressure when the fingers are naturally resting to exceed the lower limit of a fixed first threshold range (0.5N), triggering a false activation of the virtual texture mode. To address this issue, the controller continuously monitors the output signal of the piezoelectric element's sensing channel in a non-active state, and calculates the root mean square (RMS) value of the signal within a preset time window (e.g., 100ms) as a quantitative indicator of the current road vibration intensity. Based on the background noise baseline value, the first threshold range and the second threshold are dynamically adjusted according to a preset mapping relationship: on a smooth road surface (background RMS lower than the set baseline value), the first threshold range maintains its default value of 0.5N~2.0N, and the second threshold maintains 4.0N; on a slightly bumpy road surface, the first threshold range adaptively increases to 1.0N~1.5N, and the second threshold is adjusted accordingly to 4.5N; on a heavily bumpy road surface, the first threshold range adaptively increases to 1.5N~2.0N, and the second threshold is adjusted accordingly to 5.0N. The pressure range between the two thresholds is always maintained at a minimum preset distance (e.g., 2.5N) to ensure the effectiveness of the two-stage interaction logic. Simultaneously, the controller performs low-frequency noise filtering on the pressing pressure value to remove low-frequency interference introduced by road vibrations, thus obtaining the effective pressure value of active finger pressing.

[0064] The final output is: the piezoelectric element generates a perceptible tactile vibration in the boundary area of ​​the button, guiding the driver's finger to locate the target button. The driver can clearly perceive the boundary position of the button through the touch of the fingertip, thus accurately locating the target button without looking down.

[0065] By combining the aforementioned two-stage pressure threshold control with finger coordinate position mapping, the piezoelectric element drive waveform is adjusted in real time according to the finger position during the blind operation guidance stage, generating a perceptible tactile vibration in the button boundary area. This allows the driver to identify the button position and boundary by touch with their fingertips without looking down, achieving true blind operation and eliminating the accidental touch problem of flat touch panels, greatly improving driving safety. At the same time, the dynamic adaptive pressure threshold algorithm significantly reduces the false trigger rate in bumpy in-vehicle environments and maintains a low threshold sensitivity of 0.5N under stable driving conditions, balancing operational sensitivity and anti-interference reliability.

[0066] Step S103: Determine if the finger has moved to the preset position. If so, determine if the pressing pressure value exceeds the second threshold. If so, interrupt the continuous micro-vibration, drive the piezoelectric element to output a single-pulse transient strong vibration to simulate the click sensation of a mechanical button and provide a feedback operation confirmation signal. The second threshold mentioned above is the critical value of the pressing pressure in the trigger operation confirmation mode; the single-pulse transient strong vibration is a transient large-amplitude vibration used to simulate the click sensation of a mechanical button; the preset position refers to the coordinate range of the center area of ​​the target button.

[0067] Specifically, during the blind operation guidance phase, the driver moves their finger to the center area of ​​the target button based on tactile guidance. The controller monitors the finger's coordinate position (X, Y) in real time and determines whether the finger has moved to a preset position (i.e., the coordinate range of the center area of ​​the target button). If the finger has moved to the preset position, the controller further determines whether the finger pressing pressure value P exceeds a second threshold. In some embodiments, the second threshold is greater than 4.0N.

[0068] If P exceeds the second threshold, it indicates that the driver is pressing the touch surface forcefully, intending to trigger a button operation. At this time, the controller immediately interrupts the current continuous micro-vibration and drives the piezoelectric element to output a single-pulse transient strong vibration. In some embodiments, the single-pulse transient strong vibration is a single-pulse sine wave with a half wavelength of 10ms~15ms and an amplitude of 110V, so as to generate a transient acceleration of not less than 15G on the touch surface.

[0069] like Figure 4 As shown in (b), the waveform of the single-pulse transient strong vibration is a single large-amplitude transient pulse with a duration of 10ms to 15ms and an amplitude of 110V. This driving waveform causes the piezoelectric element to produce a rapid and powerful transient deformation, which is transmitted to the touch surface through the metal substrate, causing the touch surface to generate a transient acceleration of no less than 15G. This transient acceleration simulates the crisp click sensation when the metal dome inside a traditional physical switch collapses, providing the driver with a clear "successful operation" signal.

[0070] Furthermore, in combination Figure 4The waveform differences are explained as follows: Continuous micro-vibration is a sustained, constant-amplitude high-frequency waveform (200Hz~300Hz, 20Vpp), used to generate a continuous boundary tactile sensation during the blind operation guidance phase; single-pulse transient strong vibration is a single, large-amplitude transient pulse (half-wavelength 10ms~15ms, amplitude 110V), used to generate a crisp click sensation during the trigger confirmation phase. The two differ significantly in frequency, amplitude, and duration, providing drivers with two clearly distinguishable tactile feedback experiences.

[0071] The final output is: the touch surface produces a rapid and powerful transient displacement, simulating the crisp click feeling when the metal spring of a traditional physical switch collapses, and at the same time the controller outputs an operation confirmation signal to trigger the corresponding vehicle function (such as volume adjustment, answering a phone call, etc.).

[0072] By using the inverse piezoelectric effect of piezoelectric elements to generate tactile feedback, compared with traditional eccentric rotor motors and linear motors, piezoelectric elements have a fast response speed and small start-stop inertia, which can achieve low-latency and high-fidelity tactile feedback. The single-pulse transient strong vibration can simulate the crisp click of mechanical buttons, so that the driver can get a clear "operation successful" signal, and the operating experience is significantly improved.

[0073] Through the above steps S101~S103, the blind operation switch control method provided in this embodiment realizes a two-stage interactive logic of guided search and trigger confirmation: the driver first guides the positioning of the target button through fingertip touch (S102 blind operation guidance stage), and then presses the touch surface to trigger the button operation (S103 trigger confirmation stage), completing a complete interactive closed loop from button positioning to operation confirmation, and solving the problems of blind operation, high accidental touch rate and unrealistic tactile feedback of steering wheel touch switches in the prior art.

[0074] Example 3 This embodiment also provides a vehicle, including a steering wheel, on which a floating piezoelectric steering wheel button device as described in Embodiment 1 is provided, or a blind operation switch control method for the floating piezoelectric steering wheel button device as described in Embodiment 2 is executed.

[0075] As one implementation method, the vehicle can be any type of motor vehicle, such as a passenger car, commercial vehicle, or new energy vehicle. The steering wheel is equipped with the floating piezoelectric steering wheel button device of this solution, used to receive the driver's touch and press operations, enabling blind operation control of in-vehicle functions (such as volume adjustment, telephone answering, multimedia control, etc.). The in-vehicle controller executes the blind operation switch control method of this solution, driving the piezoelectric element to output corresponding tactile feedback signals based on the finger coordinate position and pressing pressure value, providing the driver with a complete tactile feedback experience for blind operation guidance and operation confirmation.

[0076] The vehicle provided in this embodiment allows drivers to locate and confirm buttons without looking down at the steering wheel, significantly improving driving safety. Simultaneously, this solution utilizes a touch surface made of optical or crystal glass combined with a multi-layered composite floating cover structure, along with the low-latency, high-fidelity tactile feedback of piezoelectric elements, giving the steering wheel buttons a premium feel reminiscent of million-dollar luxury cars, significantly enhancing the vehicle's high-end and technological appeal. Furthermore, through the synergistic cooperation of a labyrinthine waterproof structure and an elastic floating support structure, this solution's floating piezoelectric steering wheel button device meets automotive-grade waterproof and dustproof requirements, exhibiting high reliability and long-term durability.

[0077] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this embodiment.

[0078] The above description is only a preferred embodiment of the present invention. Although the specific implementation of the present invention has been described in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A suspended piezoelectric steering wheel button device, characterized in that, Includes base and controller; The base is equipped with a multi-layer composite floating cover assembly, which includes, from top to bottom and from outside to inside, a touch surface that is bonded to each other, a decorative film layer, and a metal substrate. A capacitive sensing element is attached to the back of the decorative film layer, which is used to detect the coordinate position of the finger on the touch surface; a piezoelectric element is attached to the back of the metal substrate, which uses the direct piezoelectric effect to detect the pressure value of the finger on the touch surface and transmits it to the controller, and uses the inverse piezoelectric effect to generate tactile feedback vibration; the metal substrate has a high elastic modulus and serves as a resonant cavity for the piezoelectric element, which is used to transmit the vibration generated by the piezoelectric element to the touch surface; The controller is used to drive the piezoelectric element to output a tactile feedback signal based on the finger coordinate position and the pressing pressure value.

2. The suspended piezoelectric steering wheel button device according to claim 1, characterized in that, A vertical pressing stroke is reserved between the base and the multi-layer composite floating cover assembly, and an elastic floating support structure is provided between the two. The multi-layer composite floating cover is suspended and installed on the base by the elastic floating support structure; the vertical pressing stroke is 0.10mm~0.20mm. The elastic suspension support structure is a silicone sealing ring distributed along the peripheral edge of the multi-layer composite suspension cover assembly, and the elastic deformation direction of the elastic suspension support structure is orthogonal to the propagation direction of the high-frequency vibration of the piezoelectric element.

3. The suspended piezoelectric steering wheel button device according to claim 2, characterized in that, The base is surrounded by a labyrinthine waterproof structure, which includes waterproof ribs and water-guiding grooves to form a non-contact hydrophobic channel. The labyrinthine waterproof structure works in conjunction with the elastic suspension support structure to allow vertical displacement of the multi-layer composite suspension cover assembly while preventing liquid from entering the interior of the base.

4. The suspended piezoelectric steering wheel button device according to claim 1, characterized in that, The touch surface is made of optical glass or crystal glass; the metal substrate is made of stainless steel. The decorative film layer is an IML film or an INS film, used to realize the functions of graphic printing carrier, explosion-proof backing and visual enhancement; the visual enhancement function is achieved by using the optical thickness between the decorative film layer and the touch surface to form an icon, which is visually suspended inside the touch surface.

5. The suspended piezoelectric steering wheel button device according to claim 1, characterized in that, The capacitive sensing element is a capacitor electrode, which is attached to the hollowed-out area on the back of the decorative film layer and the metal substrate; the piezoelectric element is a multi-layer stacked piezoelectric ceramic, which is fixed to the central area on the back of the metal substrate by high-strength epoxy resin adhesive. The piezoelectric element also serves as a pressure sensor and a tactile output actuator.

6. A blind operation switch control method for a suspended piezoelectric steering wheel button device as described in any one of claims 1-5, characterized in that, The controller executes a two-stage interaction logic: guiding the search and triggering confirmation. This includes: Acquire the coordinate position information of the finger on the touch surface and the pressing pressure value of the finger on the touch surface; If the pressing pressure value is within the first threshold range, then the piezoelectric element is driven to output continuous micro-vibration according to the finger coordinate position, generating a perceptible vibration sensation in the button boundary area of ​​the touch surface, guiding the finger to locate the target button. If the finger has moved to a preset position, then it is determined whether the pressing pressure value exceeds a second threshold. If so, the continuous micro-vibration is interrupted, and the piezoelectric element is driven to output a single-pulse transient strong vibration to simulate the click sensation of a mechanical button and provide a feedback operation confirmation signal.

7. The blind operation switch control method for the floating piezoelectric steering wheel button device according to claim 6, characterized in that, The first threshold range is 0.5N~2.0N, and the second threshold is greater than 4.0N; the driving frequency of the continuous micro-vibration is 200Hz~300Hz, and the amplitude is 20Vpp; the single-pulse transient strong vibration is a single-pulse sine wave with a half wavelength of 10ms~15ms and an amplitude of 110V, so that the touch surface generates a transient acceleration of not less than 15G.

8. The blind operation switch control method for the floating piezoelectric steering wheel button device according to claim 6, characterized in that, The steps for obtaining the pressure value of a finger pressing on the touch surface include: The piezoelectric element also functions as a pressure sensor. A sampling time window is inserted at the end of each driving cycle of the piezoelectric element. During the sampling time window, the output of the driving signal to the piezoelectric element is paused and the positive piezoelectric output voltage of the piezoelectric element is sampled. The sampled values ​​of multiple sampling time windows are filtered to obtain the pressing pressure value.

9. The blind operation switch control method for the floating piezoelectric steering wheel button device according to claim 6, characterized in that, Also includes: The background signal of the piezoelectric element sensing channel is continuously monitored without active operation, and the root mean square value of the background signal within a preset time window is used as a quantitative index of road vibration intensity. The first threshold range and the second threshold are dynamically adjusted according to the road vibration intensity, and the pressing pressure value is subjected to low-frequency noise filtering to ensure that the pressure range between the first threshold range and the second threshold is always not less than the preset minimum distance.

10. A vehicle, characterized in that, The system includes a steering wheel, on which a floating piezoelectric steering wheel button device as described in any one of claims 1-5 is provided, or a blind operation switch control method for the floating piezoelectric steering wheel button device as described in any one of claims 6-9 is executed.

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