Sensor assembly with force and temperature sensing capabilities

Abstract

The sensor assembly includes a temperature sensing layer configured to detect a temperature of an object in contact with the sensor assembly, a tangential force sensing layer configured to detect a tangential force applied to the sensor assembly by the object, and a floating multi-layer capacitor configured to electrically couple the temperature sensing layer to the tangential force sensing layer. And the floating multilayer capacitor is configured to detect a normal force applied to the sensor assembly by the object.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 589,989, filed on October 12, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of sensor technology, including, for example, sensors for robots. Background Art

[0004] For robots, sensors play a vital role in helping them understand the world and perform tasks more efficiently. To this end, various soft sensors with force or temperature sensing capabilities based on different working principles have been developed in an attempt to meet the requirements of dexterous object manipulation and safe human-robot collaboration.

[0005] For example, piezoresistive and piezoelectric composites can be used to identify different surface conditions by detecting pressure and vibration information. Electrical impedance can be combined with acoustic tomography to measure pressure and light touch.

[0006] The flexible temperature sensor membrane based on the composite material of plant pectin and cross-linking ions has a high-sensitivity temperature sensing performance similar to that of the natural serpentine membrane.

[0007] Traditional force measurement principles (such as piezoelectric and resistor) show good linearity in measurement, but lack directional sensitivity and cannot distinguish different directions of tangential force. On the other hand, force sensing arrays or light field measurement principles can achieve omnidirectional force sensing, but will increase the complexity of the structure.

[0008] Magnetic field sensors have good directional sensitivity and compact structure that can identify tangential forces in any direction. However, due to the change of magnetic field caused by normal pressure, and when normal force and shear force exist at the same time, the sensor cannot achieve numerical decoupling of normal force and shear force.

[0009] In addition, most traditional force and temperature measurement methods may affect each other. How to achieve temperature measurement and decoupling within a common range of scenarios is also a difficulty.

[0010] In summary, although advances have been made in conventional sensors, which enable conventional sensors to measure a variety of signals, they are still limited in numerical decoupling of multiple signals due to interference between sensing principles. Summary of the invention

[0011] In an example embodiment, the present disclosure provides a sensor assembly. The sensor assembly includes: a temperature sensing layer configured to detect a temperature of an object in contact with the sensor assembly; at least one tangential force sensing layer configured to detect a tangential force applied to the sensor assembly by the object; and a floating mountain multilayer capacitor configured to detect a normal force applied to the sensor assembly by the object.

[0012] In another embodiment, a temperature sensing layer is disposed above at least one tangential force sensing layer and a floating mountain multilayer capacitor, and wherein the temperature sensing layer provides a contact surface for an object, or is closer to a contact surface for an object than at least one tangential force sensing layer and a floating mountain multilayer capacitor.

[0013] In another embodiment, the temperature sensing layer, at least one tangential force sensing layer, and the floating mountain multilayer capacitor are connected to a controller or processor.

[0014] In another embodiment, the controller or processor is configured to independently determine the temperature of the object, the tangential force applied by the object, and the normal force applied by the object based on respective measurements of the temperature sensing layer, the tangential force sensing layer, and the floating mountain multilayer capacitor.

[0015] In another embodiment, the temperature sensing layer includes a thermosensitive ionic gel disposed within an encapsulation material.

[0016] In another embodiment, at least one tangential force sensing layer includes a Halbach magnetic film and a Hall sensor.

[0017] In another embodiment, the Hall sensor is disposed on a printed circuit board.

[0018] In another embodiment, a floating mountain type multilayer capacitor is disposed between the Halbach magnetic film and the printed circuit board.

[0019] In another embodiment, a Halbach magnetic film includes an inner portion having a first magnetization and a coaxial outer portion disposed around the inner portion and having a second magnetization opposite to the magnetization of the inner portion.

[0020] In another embodiment, detecting the tangential force includes detecting the direction of the tangential force and the magnitude of the tangential force.

[0021] In another embodiment, a floating mountain type multilayer capacitor includes two positive electrodes and two negative electrodes.

[0022] In another embodiment, two positive electrodes and two negative electrodes are arranged within a floating mountain type multilayer capacitor such that a first positive electrode is disposed above a first negative electrode, a first negative electrode is disposed above a second positive electrode, and a second positive electrode is disposed above a second negative electrode.

[0023] In another embodiment, the first positive electrode has a smaller width than the first negative electrode, the first negative electrode has a smaller width than the second positive electrode, and the second positive electrode has a smaller width than the second negative electrode.

[0024] In another embodiment, the first positive electrode is configured to move in a direction corresponding to the applied tangential force without interfering with the detection of the applied normal force.

[0025] In another embodiment, a floating mountain type multilayer capacitor includes electrodes, and wherein the floating mountain type multilayer capacitor is configured such that a distance between the electrodes decreases in a direction corresponding to the applied normal force based on application of the normal force.

[0026] In another embodiment, a floating mountain multilayer capacitor includes electrodes embedded in an elastic material.

[0027] In another exemplary embodiment, the present disclosure provides a floating mountain type multilayer capacitor. The floating mountain type multilayer capacitor includes: a plurality of electrodes; and an elastic material encapsulating the plurality of electrodes. The plurality of electrodes and the elastic material are configured such that the distance between the electrodes of the plurality of electrodes decreases in a direction corresponding to the normal force applied to the floating mountain type multilayer capacitor based on the normal force applied to the floating mountain type multilayer capacitor.

[0028] In another embodiment, the plurality of electrodes include two positive electrodes and two negative electrodes, and the two positive electrodes and the two negative electrodes are arranged within a Floating Mountain type multilayer capacitor such that a first positive electrode is disposed above a first negative electrode, a first negative electrode is disposed above a second positive electrode, and a second positive electrode is disposed above a second negative electrode.

[0029] In another embodiment, the first positive electrode has a smaller width than the first negative electrode, the first negative electrode has a smaller width than the second positive electrode, and the second positive electrode has a smaller width than the second negative electrode.

[0030] In yet another example embodiment, the present disclosure provides an apparatus for sensing tangential force. The apparatus includes: a first layer including a Halbach magnetic film; and a second layer including a Hall sensor disposed on a printed circuit board. The Hall sensor is configured to detect a voltage corresponding to a displacement of a magnetic field based on an applied tangential force.

[0031] In another embodiment, a Halbach magnetic film includes an inner portion having a first magnetization and a coaxial outer portion disposed around the inner portion and having a second magnetization opposite to the magnetization of the inner portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 An exemplary flow chart depicting a contact object interfacing with a multi-layer sensor assembly according to an exemplary embodiment of the present disclosure;

[0033] Figure 2 A schematic block diagram of a multi-layer sensor assembly capable of decoupled measurement of normal force, tangential force, and temperature according to an exemplary embodiment of the present disclosure is depicted;

[0034] FIG. 3A to FIG. 3C A schematic flow chart depicting a method of forming various components of a sensor assembly according to an exemplary embodiment of the present disclosure;

[0035] Figure 4 depicts a plot showing an exemplary simulation of a Halbach magnetic field distribution;

[0036] Figure 5 depicts a schematic diagram showing an example of how a tangential force changes the relationship between an exemplary Halbach magnetic film and a Hall sensor;

[0037] Figures 6 to 11 depicts a plot showing exemplary results of quantitative testing of exemplary implementations of the present disclosure;

[0038] FIG. 12A to FIG. 12C depicts a schematic diagram showing an example of how tangential forces and normal forces affect an exemplary floating mountain multi-layer structure according to an exemplary embodiment of the present disclosure;

[0039] Fig.12D A circuit diagram showing an example of how a conversion circuit according to an embodiment of the present disclosure connects a capacitor of an exemplary floating mountain multilayer structure is depicted; and

[0040] Figures 13 to 21 Depicted are plots showing the quality and results of quantitative testing of exemplary implementations of the present disclosure. DETAILED DESCRIPTION

[0041] Exemplary embodiments of the present disclosure provide a decoupled flexible sensor assembly capable of multi-signal sensing. This can enable, for example, higher levels of autonomous decision making and mission planning for robots.

[0042] In addition, exemplary embodiments of the present disclosure provide a multi-signal sensor assembly capable of achieving numerical decoupling between various types of signals, thereby significantly enhancing the environmental adaptability of the robot.

[0043] In an exemplary embodiment, the multi-layer flexible sensing assembly includes three types of receivers for decoupled normal force, omnidirectional tangential force, and temperature sensing, respectively. It will be understood that the sensor assembly according to an exemplary embodiment of the present disclosure can be similar to the receivers in human skin that allow a person to sense characteristics of their environment (such as pressure, temperature, and pain), thereby providing a robot with enhanced environmental sensing capabilities.

[0044] Figure 1 An exemplary flow chart of interfacing a contact object with a multi-layer sensor assembly according to an exemplary embodiment of the present disclosure is depicted.

[0045] Stage 101 represents the occurrence of contact between the sensor and the contact object. The contact includes a detectable temperature of the contact object (stage 110) and a detectable force of the contact object (stage 120).

[0046] The temperature of the contacting object affects the temperature of the sensor's ion gel, thereby changing the number of free ions within the gel, as shown in stage 111. This changes the ion gel resistance (stage 112), thereby generating an independent and clearly perceptible signal.

[0047] With respect to force detection (stage 120), the input force components include a normal force in the normal or vertical direction (stage 120a) and a tangential force in the tangential or horizontal direction (120b), both of which are defined relative to the surface of the sensor. As shown in stage 121a, the normal force acts on the floating mountain structure, compressing it in the normal direction. Since the electrode is embedded in the floating mountain structure, this vertical compression changes the capacitance of the electrode (stage 122a), thereby generating another independent and clearly perceptible signal. The tangential force causes the Halbach array magnetic film embedded in the sensor to shift (stage 121b), affecting the voltage of the Hall sensor below the magnetic film (stage 122b), thereby generating another independent and clearly perceptible signal.

[0048] Thus, as shown at stage 130 , a sensor assembly according to an exemplary embodiment of the present disclosure is capable of generating three independent and distinctly perceptible signals corresponding to temperature, normal force, and tangential force of a contact object in contact with a surface of the sensor assembly.

[0049] Figure 2 A schematic block diagram of a multilayer sensor assembly 200 capable of decoupled measurements of normal force, tangential force, and temperature according to an exemplary embodiment of the present disclosure is depicted. A circular coaxial magnetic film 202 is provided in combination with a Hall sensor 204 to measure the direction and magnitude of tangential forces in all directions (providing directional sensitivity relative to the magnetic field). In addition, for normal pressure sensing, a floating mountain multilayer structure 206 provides capacitance measurement (with good dynamic response), thereby achieving physical decoupling between normal force and tangential force. The sensor assembly 200 is further configured to perform temperature measurements based on the temperature sensitive properties of the ion gel 210, wherein the ion motion remains insensitive to external pressure and deformation, thereby allowing decoupled temperature and force measurements. Therefore, it will be understood that the sensor assembly 200 decouples the measurement capabilities of multiple signals, thereby providing the possibility of performing higher levels of robotic motion control, autonomous decision-making, and mission planning.

[0050] The measurement of omnidirectional tangential force is achieved by combining the Hall element 204 with the Halbach magnetic array 202, which is designed to be unilaterally omnidirectionally symmetrical. The direction of the tangential force is only related to the ratio of the magnetic field strength in the xy direction, and the magnitude of the tangential force is positively correlated with the total strength of the radial magnetic field. The measurement of normal pressure is achieved by capacitance measurement, and the vertical sensitivity and horizontal insensitivity of the capacitance measurement are achieved by the floating mountain multilayer structure 206. The combination of the Halbach magnetic array 202 and the floating mountain capacitor 208 maintains the directional sensitivity to magnetic field changes and the high dynamic response of the capacitance, and realizes the complete decoupling of the normal force and the tangential force. The temperature measurement utilizes the conductive properties of the ion gel 210. Since ion migration is mainly affected by temperature and is insensitive to external pressure and structural deformation, it becomes one of the best choices for temperature decoupling measurement. Therefore, the sensor assembly 200 according to the exemplary embodiment of the present disclosure is capable of simultaneously realizing omnidirectional tangential force sensing, decoupled tangential-normal force sensing, and decoupled temperature-force sensing, thereby providing the robot with the possibility of performing a higher level of environmental perception, motion control, autonomous decision-making, and task planning.

[0051] The multi-layer flexible sensor assembly 200 with three types of receivers is configured to decouple normal force sensing, omnidirectional tangential force sensing, and temperature sensing. Figure 2 As shown in , the sensor assembly includes three parts, namely, a temperature sensing layer based on ion gel, a normal force sensing layer based on capacitors, and a tangential force sensing layer based on magnetic field. Through microfabrication and molding, all these functions are integrated into a compact cylindrical unit, and in an exemplary implementation, the cylindrical structure can have a radius of 6 mm and a height of 8 mm. Unlike conventional multi-signal sensors that only provide qualitative signal ranges or use artificial intelligence to obtain approximate fitting values, the sensor assembly 200 according to an exemplary embodiment of the present disclosure can numerically decouple normal force, tangential force, and temperature through structural design and corresponding signal analysis. These accurate and decoupled signals can help robots achieve dexterous operations and complex tasks that were not possible before, without the delay and processing power required by mathematical approximations.

[0052] FIG. 3A to FIG. 3C A schematic flow chart of a method of forming various components of a sensor assembly according to an exemplary embodiment of the present disclosure is depicted.

[0053] refer to Figure 3AFor each sensor assembly, a temperature layer 300a (e.g., 1 mm thick) is fabricated using an ion gel 302 by molding followed by curing under UV light. During this period, a porous mesh fabric 304 is added for mechanical property enhancement (e.g., to maintain stable temperature measurement under stress), and encapsulation is performed using cyanoacrylate 306 or another material suitable for encapsulation to maintain sensing stability. It will be appreciated that other ways of enhancing mechanical properties (such as material modification or combination) may also be utilized.

[0054] The tangential force sensing layer 300b includes a Figure 3B The manufacturing of the magnetic film 308 in a circular Halbach pattern provides sensing of omnidirectional tangential forces. Figure 3B As shown in FIG, a rectangular magnetic film of a common Halbach array magnetization 314 is first fabricated by conventional methods, such as magnetizing, magnetron sputtering, or electrophoretic deposition of a mixture of polydimethylsiloxane (PDMS) and neodymium (NdFeB) magnetic powder. Then, a laser can be used to cut the film into small isosceles triangles 316 according to the desired magnetization pattern. Finally, these isosceles triangles 316 can be used to assemble a nearly circular Halbach magnetic film with annular magnetization 308.

[0055] In this example, a planar Halbach array magnetized film 314 with a north-south magnetic moment of 4 mm can be cut into 8 isosceles triangle modules 316 with a 45-degree vertex angle after laser cutting. The 8 isosceles triangle modules can also be arranged to obtain a nearly circular coaxial Halbach magnetization form 308. The inner circle of the assembled almost circular magnetic film is the south pole, the outer circle is the north pole, and the magnetic field lines are sinusoidally distributed from the center of the circle along the radius to the outside on the single-sided surface. This arrangement allows accurate measurement of omnidirectional tangential forces based on magnetic fields.

[0056] like Figure 3B As shown in , the planar Halbach array magnetized film 314 has triangular portions of alternating S-pole magnetization and N-pole magnetization, with the inner horizontally magnetized portion disposed therebetween. Each of the cut triangles includes a first S-pole magnetized portion and a second N-pole magnetized portion, and when assembled into an annularly magnetized approximately circular polygonal Halbach film, the S-pole magnetized portion forms a concentric polygonal ring around the inner portion of the N-pole magnetization. This arrangement provides a magnetic field distribution on one side, and the magnetic field lines are sinusoidally distributed from the center of the circle along the radius to the outside, which allows accurate measurement of the omnidirectional tangential force.

[0057] The normal force sensing layer 300c (e.g., 5 mm thick) is located between the magnetic film 308 and the PCB board 312. In order to ensure the overall displacement of the magnetic film 308 when an external tangential force is applied, an elastic material 318 (e.g., silicone elastomer) is used to encapsulate the embedded electrodes of the normal force sensing layer 300c. Figure 3C As shown, four circular electrodes 320 having different sizes are embedded with a gap (eg, 1 mm) through repeated molding operations to form a normal force sensing layer.

[0058] The signals from the temperature sensing layer 300a, the tangential force sensing layer 300b, and the normal force sensing layer 300c are connected to a controller (e.g., a microcontroller unit (MCU)) through circuits on the PCB 312. By monitoring the changes in resistance, magnetic field, and capacitance, the temperature, tangential force, and normal force information can be obtained, respectively.

[0059] The directional sensitivity of the magnetic field makes it very suitable for measuring tangential forces in any direction. Unlike other magnetic field-based sensor designs, the magnetic film 308 according to the exemplary embodiment of the present disclosure adopts Figure 3B Characteristic of the circular pattern of magnetization in a coaxial Halbach array. Magnets and magnet sensors usually have a single pair of poles and are not coaxially arranged.

[0060] Figure 4 Depicted is a plot 400 showing an exemplary simulation of a Halbach magnetic field distribution that provides a unique magnetization pattern that produces a spatial distribution of magnetic fields on one side that resembles a coaxial sinusoidal pattern. Figure 4 is a cross-sectional side view of the magnetic film, which shows the difference in magnetic field distribution between the upper surface and the lower surface of the magnetic film.

[0061] Figure 5 Depicted is a diagram showing how tangential force changes the relationship between an exemplary Halbach magnetic film 502 and a Hall sensor 504 (corresponding to Figure 4 Due to the unique magnetization pattern mentioned above, when a tangential external force acts on the sensor assembly, the direction of the tangential force can be determined by measuring the direction of the magnetic field, and the magnitude of the tangential force is positively correlated with the magnitude of the tangential component of the magnetic field in that direction.

[0062] In addition, the one-sided distribution of the magnetic field can reduce the influence of external magnetic materials on the sensor's measurement, making the measurement results more stable and accurate compared to sensors using conventional magnetic films. Figure 4 As shown in , the magnetic field is weaker on the upper surface of the magnetic film (corresponding to the outside of the sensor) and stronger on the lower surface of the magnetic film (corresponding to the inside of the sensor). This means that the sensor is less affected by external magnetic materials while maintaining its own high measurement sensitivity.

[0063] Additionally, tests were performed to provide quantitative characterization of the magnetic field distribution and tangential force measurement performance. Figures 6 to 11 A plot showing exemplary results of such quantitative testing of exemplary implementations of the present disclosure is depicted.

[0064] Figure 6 The variation of tangential magnetic field intensity along the radius of the circular magnetic film is shown. Due to the coaxial circular magnetization distribution, the tangential magnetic field intensity is the same and varies sinusoidally in all directions at the same height distance. The tangential displacement interval of 0-2.5mm is adopted within the working range of the sensor, which can be Figure 7 It is observed that for a given height ΔH, the tangential displacement has a one-to-one correspondence with the magnetic field strength, which means that the magnitude of the tangential force corresponds to the magnitude of the tangential magnetic field strength. See the ground truth at ΔH = 0 mm (702), 1 mm (704) and 2 mm (706), and the fitting curves at ΔH = 0 mm (708), 1 mm (710) and 2 mm (712). This shows the correspondence between the tangential magnetic field strength and the tangential force at different heights ΔH.

[0065] Figure 8 It is shown that at a given height ΔH, the tangential magnetic field strength initially increases linearly with increasing tangential force. See the values ​​at ΔH = 0 mm (802), 1 mm (804) and 2 mm (804). However, when approaching the boundary region (ΔR = 2.5 mm), the magnetic field increase slows down (indicating a reduced sensitivity when measuring the tangential force near the boundary region), consistent with the sinusoidal variation pattern of the tangential magnetic field strength. The direction of the tangential force is related to the direction of the tangential magnetic field.

[0066] Fig. 9 The inverse tangent of the ratio of By and Bx is depicted in relation to the direction of the tangential force, where By and Bx correspond to the strength of the magnetic field in the y-direction and the x-direction, respectively. It can be observed that they do not have a one-to-one correspondence due to the presence of both positive and negative values ​​in the direction of the magnetic field. Referring to the values ​​at ΔH = 0 mm (902), 1 mm (904) and 2 mm (906), it follows that Fig. 9 Each of the three lines shown in has three overlapping lines corresponding to ΔH=0 mm (902), 1 mm (904) and 2 mm (906). Therefore, the direction of the tangential force is related to the inverse tangent of the ratio of By and Bx and is independent of the magnitude of the different normal forces.

[0067] exist Fig.10 By correcting the sign of the tangential magnetic field in the x and y directions, a completely linear angular relationship can be obtained. See the values ​​when ΔH = 0 mm (1002), 1 mm (1004) and 2 mm (1006), thus Fig.10 The single line shown in has three overlapping lines corresponding to ΔH=0 mm (1002), 1 mm (1004) and 2 mm (1006). Therefore, it can be concluded that the measurement direction of the tangential force F is independent of the normal pressure (in the height direction), and the measurement direction of the tangential force is also independent of the magnitude of the tangential force (see Fig.11 ). This is also consistent with actual observations.

[0068] The measurement of normal force is based on the change of capacitance. In order to mitigate the influence of tangential force, a floating mountain type multilayer structure according to an exemplary embodiment of the present disclosure is used. FIG. 12A to FIG. 12C A schematic diagram illustrating an example of how tangential forces and normal forces affect an exemplary floating mountain multilayer structure according to an exemplary embodiment of the present disclosure is depicted. In particular, Fig. 12A A capacitor comprising two sets of positively and negatively charged electrodes (the electrodes have different lengths that increase gradually from top to bottom) is shown with no force applied to the capacitor.

[0069] When subjected to a tangential force, the electrode undergoes a displacement in the horizontal plane, e.g. Fig. 12B As shown in . Due to the floating mountain structure design, the effective area of ​​the capacitor remains constant within the operating range. Therefore, the measurement of the capacitor in the normal direction can be independent of the tangential force.

[0070] When experiencing Fig. 12C When the normal pressure shown in , the distance between the electrodes decreases, resulting in an increase in capacitance. Thus, by measuring the capacitance value, the normal displacement and force can be calculated accordingly.

[0071] Fig.12D Depicts the conversion circuit in an embodiment and how the conversion circuit can be connected to a capacitor as part of a sensor assembly. Fig.12D In the figure, C corresponds to a floating mountain type multilayer capacitor; R1 and R2 are matching resistors; and the circuit output is a variable frequency square wave, where the frequency is determined by the size of the matching resistor and capacitor.

[0072] To facilitate capacitance measurement, this conversion circuit can be used to convert capacitance measurement into frequency measurement. The relationship between capacitance and output frequency can be as follows:

[0073]

[0074] Wherein, f represents the output frequency, R1 and R2 indicate the resistance in the circuit, and C expresses the capacitance. This method can accurately measure the capacitance value, and thus can accurately measure the normal force while effectively decoupling the normal force from the tangential force.

[0075] Figures 13 to 21Depicted are plots showing the quality and results of quantitative testing of exemplary implementations of the present disclosure.

[0076] Fig.13 and Fig.14 Depicted are tests that characterize an exemplary configuration, establishing a relationship between normal displacement and output frequency ( Fig.13 ) and the relationship between normal force and output frequency ( Fig.14 ). In addition, tests have verified that the Fushan multilayer capacitor is independent of tangential forces. Fig.15 The results are depicted when the tangential force is gradually increased from 0 to 2 Newtons while maintaining a constant normal force, where the measured normal force remains stable. See the values ​​for Fn = 1 N and EMS = .005 (1502), Fn = 3 N and EMS = .001 (1504), and Fn = 5 N and EMS = .003 (1506). This shows that the normal force is independent of and decoupled from the tangential force, confirming the effectiveness of the design in isolating these two force components.

[0077] For temperature measurement, the temperature-sensitive properties of ion gels are utilized. Typically, ion gels contain two types of ions: non-free ions 1602 (non-free ions are bound and fixed within polymer chains 1604) and free ions 1606 (free ions are not bound). When a voltage is applied across the gel, the free ions 1606 move in response to the electric field, thereby generating an electric current. The greater the number of free ions 1606, the lower the resistance the gel exhibits to the external circuit. As the temperature increases, the distance between the polymer chains 1604 within the gel increases, resulting in more non-free ions 1602 being converted into free ions 1606. Ultimately, this results in the temperature-sensitive properties of the gel, wherein the resistance of the gel decreases as the temperature increases. Fig.16 Describes this relationship.

[0078] Fig.17 Results from using an equivalent voltage divider circuit to study the relationship between temperature and current within the gel are shown. Compared to conventional temperature-sensitive materials, the apparent resistance of the ion gel is only related to the amount of free ions in the ion gel and remains insensitive to external pressure or deformation. This property is advantageous for decoupled measurements of temperature and force, as demonstrated in comparative experiments. Fig.18 The experimental comparison of temperature measurement with and without load (10 N) is depicted. When the ambient temperature increases from 20 to 80 degrees, the ratio of the temperatures measured in the two states always remains between 0.99 and 1.01.

[0079] also, Fig.19 and Fig. 20The changes in the current within the gel during slow and fast temperature changes are depicted, respectively. They are almost identical in both cases. However, due to the time delay of temperature conduction, the current change lags by 20-30 milliseconds. Fig.21 The repeatability of temperature sensing is shown. The current range within the ion gel shows little decay after 50 cycles.

[0080] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0081] The use of the terms "the" and "at least one" and similar designations in the context of describing the present invention (especially in the context of the appended claims) should be interpreted as covering the singular and the plural, unless otherwise stated herein or clearly contradicted by the context. The use of the term "at least one" after a list of one or more items (e.g., "at least one of A and B") should be interpreted as indicating any combination of one item (A or B) or two (A and B) or more of the listed items, unless otherwise stated herein or clearly contradicted by the context. Unless otherwise stated, the terms "comprising", "having", "including" and "containing" should be interpreted as open terms (i.e., meaning "including but not limited to"). Unless otherwise stated herein, the description of the numerical range herein is intended only as a convenient method of individually referencing each independent value falling within the range, and each independent value is incorporated into the specification as if it were individually cited. All methods described herein can be performed in any suitable order, unless otherwise stated herein or otherwise clearly contradicted by the context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better illuminate the invention and does not limit the scope of the invention unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0082] Preferred embodiments of the present invention are described herein, including the best mode known to the inventor for implementing the present invention. After reading the above description, variations of the above preferred embodiments will be apparent to those of ordinary skill in the art. The inventor expects those skilled in the art to appropriately adopt such variations, and the inventor intends to practice the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalents of the subject matter listed in the appended claims as permitted by applicable law. In addition, any combination of all possible variations of the above elements is included in the present invention, unless otherwise stated herein or otherwise clearly contradictory to the context.

Claims

1. A sensor assembly, comprising: a temperature sensing layer configured to detect a temperature of an object in contact with the sensor assembly; at least one tangential force sensing layer configured to detect a tangential force applied to the sensor assembly by the object; as well as A floating-mount multilayer capacitor is configured to detect a normal force applied to the sensor assembly by the object.

2. The sensor assembly according to claim 1, wherein: The temperature sensing layer is disposed above the at least one tangential force sensing layer and the floating mountain multilayer capacitor, and wherein the temperature sensing layer provides a contact surface for the object or is closer to the contact surface for the object than the at least one tangential force sensing layer and the floating mountain multilayer capacitor.

3. The sensor assembly according to claim 1, wherein: The temperature sensing layer, the at least one tangential force sensing layer, and the floating mountain multilayer capacitor are connected to a controller or processor.

4. The sensor assembly according to claim 3, wherein: The controller or the processor is configured to independently determine the temperature of the object, the tangential force applied by the object, and the normal force applied by the object based on respective measurements of the temperature sensing layer, the tangential force sensing layer, and the floating mountain multilayer capacitor.

5. The sensor assembly according to claim 1, wherein: The temperature sensing layer includes a thermosensitive ion gel disposed within an encapsulating material.

6. The sensor assembly according to claim 1, wherein: The at least one tangential force sensing layer includes a Halbach magnetic film and a Hall sensor.

7. The sensor assembly according to claim 6, wherein: The Hall sensor is arranged on a printed circuit board.

8. The sensor assembly according to claim 7, wherein: The floating mountain type multilayer capacitor is disposed between the Halbach magnetic film and the printed circuit board.

9. The sensor assembly according to claim 6, wherein: The Halbach magnetic film includes an inner portion having a first magnetization and a coaxial outer portion disposed around the inner portion and having a second magnetization opposite to the magnetization of the inner portion.

10. The sensor assembly according to claim 1, wherein: Detecting the tangential force includes detecting the direction of the tangential force and the magnitude of the tangential force.

11. The sensor assembly according to claim 1, wherein: The Fushan-type multilayer capacitor includes two positive electrodes and two negative electrodes.

12. The sensor assembly according to claim 11, wherein: The two positive electrodes and the two negative electrodes are arranged within the Floating Mountain type multilayer capacitor such that a first positive electrode is disposed above a first negative electrode, the first negative electrode is disposed above a second positive electrode, and the second positive electrode is disposed above a second negative electrode.

13. The sensor assembly of claim 12, wherein: The first positive electrode has a smaller width than the first negative electrode, the first negative electrode has a smaller width than the second positive electrode, and the second positive electrode has a smaller width than the second negative electrode.

14. The sensor assembly according to claim 12, wherein: The first positive electrode is configured to move in a direction corresponding to the applied tangential force without interfering with the detection of the applied normal force.

15. The sensor assembly of claim 1, wherein: The Floating Mountain type multilayer capacitor includes electrodes, and wherein the Floating Mountain type multilayer capacitor is configured such that a distance between the electrodes decreases in a direction corresponding to the applied normal force based on application of the normal force.

16. The sensor assembly of claim 1, wherein: The floating mountain type multilayer capacitor includes electrodes embedded in an elastic material.

17. A Fushan-type multilayer capacitor, comprising: Multiple electrodes; as well as an elastic material encapsulating the plurality of electrodes, The plurality of electrodes and the elastic material are configured such that a distance between electrodes of the plurality of electrodes decreases in a direction corresponding to a normal force applied to the floating mountain type multilayer capacitor based on the normal force applied to the floating mountain type multilayer capacitor.

18. The floating mountain type multilayer capacitor according to claim 17, wherein: The multiple electrodes include two positive electrodes and two negative electrodes, and the two positive electrodes and the two negative electrodes are arranged in the Fushan-type multilayer capacitor such that a first positive electrode is disposed above a first negative electrode, the first negative electrode is disposed above a second positive electrode, and the second positive electrode is disposed above a second negative electrode.

19. The floating mountain type multilayer capacitor according to claim 18, wherein: The first positive electrode has a smaller width than the first negative electrode, the first negative electrode has a smaller width than the second positive electrode, and the second positive electrode has a smaller width than the second negative electrode.

20. A device for sensing tangential force, the device comprising: The first layer includes the Halbach magnetic film; as well as The second layer includes a Hall sensor disposed on a printed circuit board, Wherein, the Hall sensor is configured to detect a voltage corresponding to a displacement of the magnetic field based on the applied tangential force.

21. The device according to claim 20, wherein: The Halbach magnetic film includes an inner portion having a first magnetization and a coaxial outer portion disposed around the inner portion and having a second magnetization opposite to the magnetization of the inner portion.

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