WO2015143281A1 - Capteur de force multi-axe, monolithique - Google Patents

Capteur de force multi-axe, monolithique Download PDF

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Publication number
WO2015143281A1
WO2015143281A1 PCT/US2015/021683 US2015021683W WO2015143281A1 WO 2015143281 A1 WO2015143281 A1 WO 2015143281A1 US 2015021683 W US2015021683 W US 2015021683W WO 2015143281 A1 WO2015143281 A1 WO 2015143281A1
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WIPO (PCT)
Prior art keywords
layer
sensor
monolithic
strain
scaffold
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PCT/US2015/021683
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English (en)
Inventor
Joshua GAFFORD
Samuel Kesner
Conor Walsh
Robert Wood
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President And Fellows Of Harvard College
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Publication of WO2015143281A1 publication Critical patent/WO2015143281A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/22—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers
    • G01L5/226—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers to manipulators, e.g. the force due to gripping
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/30—Surgical robots
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/70—Manipulators specially adapted for use in surgery
    • A61B34/76—Manipulators having means for providing feel, e.g. force or tactile feedback
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
    • G01L5/161—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using variations in ohmic resistance
    • G01L5/1627—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using variations in ohmic resistance of strain gauges
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/70—Manipulators specially adapted for use in surgery
    • A61B34/74—Manipulators with manual electric input means
    • A61B2034/742—Joysticks
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/06—Measuring instruments not otherwise provided for
    • A61B2090/064—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension

Definitions

  • MIS minimally invasive surgical
  • Haptic feedback has been explored in many areas of surgery, including laparoscopic surgery, microsurgery, and vitreoretinal surgery.
  • Haptic feedback implementations can be broken into kinesthetic (force sensing) and cutaneous
  • FBG optical fiber Bragg grating
  • measured forces at the tool tip are contaminated by friction and reaction forces at the point of entry, as well as by actuation forces and by the mechanics of the tool itself, which makes this proximal placement less desirable than distal placement of the sensor, as shown in FIG. 2.
  • a monolithic, multi-axis force sensor and methods for its fabrication and use are described herein.
  • Various embodiments of the apparatus and methods may include some or all of the elements, features, and steps described below.
  • a monolithic, multi-axis force sensor can be in the form of a laminated structure including a scaffold; a plurality of arms extending within and across the scaffold at distinct angles, wherein the arms include a structural support layer, a sensor layer including a strain-gauge alloy, and a flexible and electrically insulating polymer layer sandwiched between the structural support layer and the sensor layer in a monolithic, multi-layered laminate structure; and electrically conductive pathways positioned to deliver a voltage through the strain-gauge alloy in the arms.
  • the multi-axis force sensor can be fabricated by aligning a polymer layer comprising a flexible and electrically insulating polymer on a substrate layer;
  • a sensor layer comprising a strain-gauge alloy on the polymer layer; and joining the substrate layer, the polymer layer, and the sensor layer to form a monolithic multi-layered laminate structure, wherein the substrate layer forms a scaffold, and wherein the sensor layer is included in a plurality of arms extending within and across the scaffold and is configured to produce a change in electrical resistance through the sensor layer as the arms are displaced with strain.
  • the monolithic sensor can be used for multi-axis force sensing by contacting an object with a remote-controlled tool coupled with the monolithic force sensor.
  • an electrical current is passed through the strain-gauge alloy as the tool contacts the object.
  • the resistivity of the strain-gauge alloy is tracked as the tool contacts the object.
  • a determination is made of the force vectors applied to the tool as it contacts the object as a function of changes in the resistivity of the strain-gauge alloy.
  • Those force vectors are communicated to an operator ⁇ e.g., a surgeon) operating the tool via remote control.
  • the inventors have rapidly prototyped customized, highly sensitive, mm-scale multi-axis force sensors for medical applications.
  • the inventors Using a composite laminate batch fabrication process with biocompatible constituent materials, the inventors have fabricated a fully-integrated, 10 x 10 mm three-axis force sensor with up to 5 V/N sensitivity and root-mean-square (RMS) noise on the order of -1.6 mN, operational over a range of -500 to 500 mN in the x- and /-axes, and -2.5 to 2.5 N in the ⁇ -axis.
  • Custom foil-based strain sensors were fabricated in parallel with the mechanical structure, obviating the need for post-manufacturing alignment and assembly.
  • the sensor and its custom-fabricated signal conditioning circuitry fit within a 1 x 1 x 2 cm volume to realize a fully integrated force transduction platform with potential haptics and control applications in minimally invasive surgical tools.
  • the form factor, bio compatibility, and cost of the sensor and signal conditioning makes this method advantageous for the rapid prototyping of low-cost, mm-scale distal kinesthetic force sensors.
  • Sensor performance is validated in a simulated tissue palpation task using a robotic master-slave platform.
  • FIGS. 1 and 2 show proximal and distal sensing, respectfully with a sensor 12 mounted on a surgical tool, wherein the sensor 12 is outside the skin in FIG. 1 and under the skin in FIG. 2.
  • FIG. 3 shows a triaxial force sensor 12 with a Maltese cross morphology.
  • FIG. 4 shows the deformation modes (exaggerated for clarity)
  • FIG. 5 illustrates a finite element analysis of sensor performance under loading in the ⁇ -direction.
  • FIG. 6 illustrates fine element analysis of sensor performance under loading in the ⁇ -direction.
  • FIG. 7 shows a signal conditioning circuit schematic, wherein a tunable half- bridge feeds an instrumentation amplifier with a gain of 1000 and a voltage offset of
  • FIG. 8 shows uniaxial deformation for an infinitesimal element of a strain gage 18.
  • FIG. 9 shows an optimization analysis ofx- and /-direction sensitivities, where the inputs are arm width, w, and arm thickness, t, and the output is the resulting voltage normalized for a 1 N load.
  • the labeled contours give mechanical factors-of- safety.
  • FIG. 10 includes an exploded view of a sensor, showing structural, sensing, and encapsulation sublaminates.
  • FIG. 11 shows millimeter-scale triaxial force sensors 12 as fabricated in a batch-manufacturing process.
  • sensors 12 are shown pre-release, while still attached to an alignment scaffold 14.
  • At center bottom is a flat sensor 12 post-release.
  • a sensor 12 is shown with stiffening struts folded up and locked into place with a ball of solder.
  • FIG. 12 is a top view of a sensor 12 with callouts to various wiring and assembly features; and a magnified image (obtained from a scanning electron microscope) of the manufactured sensor before encapsulation.
  • FIG. 13 shows a test setup for obtaining sensor calibration data.
  • FIG. 14 shows a calibration curve obtained for differential output voltage using the test setup of FIG. 13 as a function of force.
  • FIG. 16 shows a quantitative palpation evaluation obtained via an
  • FIG. 17 shows a measurement using the experimental setup of FIG. 16, wherein a characteristic palpation force profile demonstrating a dominant z- component is measured.
  • FIG. 18 shows an experimental curve produced from an Ecoflex-0010 indentation test with the setup of FIG. 16 compared with analytical Hertzian and Mooney-Rivlin models.
  • FIGS. 19-21 illustrate a high-bandwidth, 2-axis, arm force sensor formed by folding a monolithic laminar structure, wherein FIG. 19 is a top view, preassembly; FIG. 20 is a front view, after folding and locking; and FIG. 21 is an isometric view showing sensitive axes.
  • FIGS. 22 and 23 illustrate stacked triaxial force sensors 12, which can be fabricated via folding, as shown in FIGS 19-21.
  • the layers When the layers are "popped up," they enable 6-axis force sensing because strain gages 18 on perpendicular faces allow for torque sensing; the six axes of sensing are as follows: F x , F y , F z , 3 ⁇ 4 r , and ⁇ ⁇ .
  • FIG. 24 shows the fabrication, assembly and release steps in a schematic representation of the fabrication of a pop-up MEMS device.
  • FIG. 25 illustrates four stages (a)-(d) in the formation of folding joints 21.
  • FIGS. 26-28 provide schematic illustrations of folding and locking steps with brass plates 47 and solder 48.
  • the composition may be substantially, though not perfectly pure, as practical and imperfect realities may apply; e.g., the potential presence of at least trace impurities ⁇ e.g., at less than 1 or 2%) can be understood as being within the scope of the description; likewise, if a particular shape is referenced, the shape is intended to include imperfect variations from ideal shapes, e.g., due to manufacturing
  • Percentages or concentrations expressed herein can represent either by weight or by volume. Processes, procedures and phenomena described below can occur at ambient pressure ⁇ e.g., about 50-120 kPa— for example, about 90-110 kPa) and temperature ⁇ e.g., -20 to 50°C— for example, about 10-35°C).
  • first, second, third, etc. may be used herein to describe various elements, these elements are not to be limited by these terms. These terms are simply used to distinguish one element from another. Thus, a first element, discussed below, could be termed a second element without departing from the teachings of the exemplary embodiments.
  • the various components identified herein can be provided in an assembled and finished form; or some or all of the components can be packaged together and marketed as a kit with instructions ⁇ e.g., in written, video or audio form) for assembly and/or modification by a customer to produce a finished product.
  • the inventors have developed a new class of cost-effective, mm-scale sensors that can be implemented distally to generate a pure measurement of the applied force at the tissue interface.
  • an approach is presented that can be used to batch fabricate low-cost, high-resolution three-axis force sensors.
  • Embodiments of the sensor can be constructed out of biocompatible materials and can fit within the size constraints imposed by MIS procedures.
  • Such a sensor 12 can be used, in particular, for applications in which the applied force is relatively low ⁇ e.g., less than 1 N), including tissue palpation and characterization, microsurgery, and vitreoretinal surgery, to name a few.
  • the level of force detection can extend down to the limit of resolution, which can be 1.6 mN in the x- and y- axes and 16 mN in the z- axis.
  • surgery on a patient can be performed using robotic tools, wherein the human surgeon (or other operator) controls the tool ⁇ e.g., by manually manipulating an input device, such as a "joystick" from a remote location.
  • Readings of the force vectors (and/ or torque) sensed by the tool 22 (along three orthogonal axes) via the sensor 12 are processed and communicated ⁇ e.g., electronically and/or wirelessly) to the surgeon's input device; and the input device can be displaced and/or can change in stiffness via a vector/torque-force feedback mechanism in accord with the force vector and/ or torque measurements provided by the sensor 12 so that the surgeon can haptically "feel" a representation of the patient's internal tissues and other internal structures that contact the tool 22 via the surgeon's remote input device.
  • the forces that are presented to the operator can be processed and/or amplified to improve human perception.
  • the surgeon can also manipulate the input device, and the surgeon's movements can be recorded by the input device and communicated to actuators coupled with the tool 22 to manipulate the tool 22 in accord with the surgeon's motions.
  • the sensors 12 can also be used in a wide variety of applications, such as in portable electronics, where the sensors 12 can, for example, measure forces against the display screen of the device ⁇ e.g., when a user accidentally sits on the device) and may issue a warning to the user if the force is high enough to potentially damage the display screen.
  • the sensors 12 can also be used in various other forms of instrumentation and metrology in a manner similar to the use of commercially available load cells and in other applications, where less-expensive, more-sensitive, lower-profile and lightweight sensors are used.
  • the sensor electronics can be an integral part of the sensor 12 so the electronics can operate as standalone measurement units individually or as part of an easily reconfigurable sensor network with modular units, thus saving the need for expensive and potentially bulky off-board signal processing and transmission electronics.
  • the sensors 12 can be embedded in or placed on shelves, where they can provide a force reading to indicate how full the shelf is.
  • the sensors 12 can also be used in a variety of assembly processes involving manipulation of fine and/or delicate components ⁇ e.g., watch assembly).
  • a simple button interface ⁇ e.g., light, medium, or large forces cause three different behaviors in the device.
  • the sensor electronics e.g., data acquisition, signal conditioning, signal processing, and communication ⁇ e.g., wireless
  • the sensors 12 can be embedded in or placed on shelves, where they can provide a force reading to indicate how full the shelf is.
  • the sensors 12 can also be used in a variety of assembly processes involving manipulation of fine and/or delicate components ⁇ e.g., watch assembly).
  • the sensors 12 can used for viscous force measurement.
  • such a platform presents an ultra-low-cost ( ⁇ $10) alternative to commercial sensors (which often cost up to $l,000/axis) to realize smart, disposable sensors for some of the above-mentioned applications.
  • a sensor can be used to create a disposable surgical tool 22 that can provide haptic feedback or can be tagged to items or shelves in a retail or industrial setting.
  • Cross topology is adopted, including a suspended platform ('probe') attached to a structural ground via axisymmetric flexures that transmit motion in the desired sensing degrees of freedom.
  • This morphology is shown in FIG. 3, where four arms 16, each with a strain gage 18 layered thereon, extend across the sensor 12 (at orthogonal angles from one another) from the scaffold 14 to the central mount 20 for the tool 22. While the tool 22 here is shown as a probe, the tool 22 in other
  • embodiments can take other forms, such as a grasper or cutter.
  • Signals generated by the strain gages 18 bonded to these flexures can be combined to determine the magnitude and direction of the force applied at the probe 22 in N axes so long as the number of gages 18, n gages > N.
  • a three-axis sensor 12 is presented, where each arm 16 has two strain gages 18 (one in tension and one in compression). The combination of signals generated by each arm 16 under load can be reconstructed into a three-dimensional applied force vector.
  • F z is the applied load
  • h is the distance between strain and the arm's neutral axis
  • Eis the Young's Modulus
  • / is the second moment of area
  • l b is the length of the beam (arm) 16.
  • F x is the applied load; ris the distance defined in FIG. 4; and L is the probe length.
  • strain profiles normalized and plotted as a function of distance along the arml6 (also normalized to arm length, l b ), are shown in the plots of FIG. 4 for each loading condition.
  • the strain profile In the case of ⁇ --loading, the strain profile is antisymmetric about the midpoint of the arml6, whereas for x- or ⁇ -loading, the zero strain crossing is slightly offset from the midpoint.
  • the strain gage coverage area comprises a significant portion of the arm surface area, so it is inaccurate to consider only the maximum strain in gage analysis. Instead, the average value of strain integrated is considered over the strain gage length.
  • the average strain, ⁇ is defined as follows: ⁇ — ⁇ j
  • the length of the strain gage 18 was limited to half of the arm length (noting that if the strain gage length exceeds half of the arm length, desensitization occurs due to a reversal in the direction of strain as shown in the normalized strain plots in FIG. 4).
  • metal foil strain gages 18 can be custom-designed on an application-specific basis using a thorough understanding of strain-gage mechanics and an anticipation of the strain levels that the strain gage 18 is predicted to endure. Accurately predicting strain-gage performance pre-fabrication is advantageous to ensure that sensitivity requirements are satisfied in light of mechanical constraints.
  • strain gage resistance under loading can be expressed as a linear function of the nominal (unloaded) resistance and the average strain, which was computed previously. This methodology can be used to predict strain gage behavior when designing custom strain gages on an application-specific basis.
  • this design sensitivity corresponds to a mechanical factor of safety (defined as ⁇ J y /a max ) of around 2-3 for a 1 N load, as shown by the contour lines. These dimensions result in a ⁇ -sensitivity (analysis not shown) of roughly 0.6 V/N. Note that mechanical yield defines the geometry limit.
  • the monolithic structure of the sensor 12 can be fabricated in parallel with the sensing elements to realize a fully-integrated multi-axis sensor 12 with no need for post-manufacturing alignment, bonding or assembly. Manufacturing:
  • the embodiment of the sensor 12 shown in FIG. 10 comprises a multi-material laminate composed of several functional sub-laminates.
  • Rigid 304 Stainless steel shim stock 38 (four layers, where each layer is 50 ⁇ thick) forms the core of a structural support layer that dominates the mechanical behavior of the sensor 12.
  • Kapton polyimide 36 (25 ⁇ thick) is a polymer used as (1) a flexible layer allowing active hinges to transmit motion and (2) an electrically insulating and encapsulating layer to isolate the strain gage 18.
  • Mangan 40 (a 45% Cu / 55% Ni alloy, 5 ⁇ thick) is used as the strain gage alloy (in a sensor layer) due to its versatility and similarity to 304SS in terms of thermal expansion; and it offers an electrical resistivity that is substantially constant over a wide range of temperatures.
  • DuPont Pyralux FR1500 sheet adhesive 34 (12.5 ⁇ thick) is used to bond subsequent layers. All materials with the exception of the adhesive 34 are biocompatible; a thin parylene [poly(p-xylylene polymer) coating can be deposited onto the sensor structure to cover the other layers for complete bio compatibility. Each of these layers can be laser machined to form the illustrated shapes and profiles. Additional layers include copper pads 32 and solder 42, wherein the copper pads 32 and solder 42 provide electrically conductive pathways and are positioned to deliver a voltage (electric current) through the strain-gage alloy 40 in each of the arms 16.
  • constantan 40 is the oldest and still the most widely used.
  • the acceptance of constantan 40 reflects the fact that constantan 40 has the best overall combination of properties needed for many strain gauge applications.
  • This alloy has, for example, an adequately high strain sensitivity or gauge factor, which is relatively insensitive to strain level and temperature. Its resistivity is high enough to achieve suitable resistance values in even very small grids, and its temperature coefficient of resistance is not excessive.
  • constantan 40 is characterized by good fatigue life and relatively high elongation capability.
  • an alternative strain-gage alloy such as manganin (Cu86Mni2Ni 2 ) can be used.
  • the manufacturing process of the sensor 12 can be similar to that outlined in J. Gafford, et al, "Force-Sensing Grasper Enabled by Pop-Up Book MEMS" IEEE IROS, Tokyo, Japan (2013). Layers are individually machined using a diode-pumped solid-state (DPSS) laser, plasma etched with Argon gas to promote surface adhesion, and laminated in a heat press at 50 psi and 200°C for 2 hours. After lamination, the strain gage pattern is cut using the laser, and the sensor 12 is encapsulated in an additional Kapton layer (with breakout contacts) prior to the final release cuts. After release cuts are made, the stiffening struts are folded, locked, and soldered; and the sensor 12 is wired to the signal conditioning circuitry.
  • DPSS diode-pumped solid-state
  • millimeter-scale triaxial force sensors 12 in a batch- manufacturing process is shown in FIG. 11 ⁇ i.e., many sensors 12 can be
  • FIG. 11 manufactured in parallel across a large scaffold 14).
  • the sensors 12 are shown pre-release, while still attached to the alignment scaffold 14.
  • At center bottom is a flat sensor 12 post-release.
  • a sensor 12 is shown with stiffening struts folded up and locked into place with a ball of solder.
  • a US penny provides scale.
  • a combination of active hinges 24 (castellated hinges approximating pin- joint motion), plastic hinges (serrated material that plastically deforms when folded), and snapfit features allow for precision folding into a robust, 3-dimensional assembly which stiffens the structure and localizes deformation to the flexural elements.
  • a microscope image of the sensor prototype, pre-encapsulation, is shown via the call- out in FIG. 12; the gage arm width here is shown to be 30 ⁇ .
  • FIG. 12 provides a top view of the sensor 12, with the scaffold 14, arms 16, strain gage 18, central mount 20, copper 32 and solder 42 conductive pathways, and the mounting holes 26 in the scaffold 14.
  • the mounting holes 26, which are provided in each layer, are aligned with fixed mounting pins that feed through the holes 26 as the layers are stacked so that each layer is precisely aligned with the others via the alignment of its mounting holes 26 with the mounting pins.
  • the arms 16 are attached to the scaffold 14 at corners for increased stiffness.
  • this attachment point is not perfectly rigid; and a small amount of local deformation occurs at the corners due to strain diffusion.
  • placing the strain gages 18 on the probe half of the arms 16 becomes beneficial, where the attachment of the probe 22 more closely approximates a rigid connection point. Due to symmetry, loading in the /-direction results in behavior that is substantially identical (beyond the directional difference) to behavior due to loading in the ⁇ -direction.
  • An on-board signal conditioning circuit was designed to amplify the strain gage output such that reasonable transistor-transistor logic (TTL) voltage levels can be processed by a data acquisition system (DAQ).
  • TTL transistor-transistor logic
  • DAQ data acquisition system
  • On-board sensing can ensure that resistive/inductive contributions from leadwires are minimized pre-amplification, so the design challenge is to minimize the footprint of the signal conditioning printed circuit board (PCB) to dimensions similar to those of the sensor 12, itself.
  • PCB signal conditioning printed circuit board
  • FIG. 7 a half bridge with precision (0.05% tolerance) reference resistors feeds an AD8221 instrument amplifier with tunable gain.
  • the amplifier gain was set to 1,000 such that a 500 mN load results in an ⁇ 2.5 V voltage swing.
  • the half-bridge configuration ensures adequate temperature compensation and long-term stability.
  • a high-impedance tuning potentiometer allows for manual zero-offset calibration coverage for up to 5% strain gage resistance mismatch with negligible effect on linearity and sensitivity.
  • the sensor 12 is designed for a single supply, so a mid-level voltage reference is established by a buffered on-board voltage divider so that positive and negative forces can both be measured.
  • the custom PCB measuring 10 x 20 mm, was fabricated in-house via direct-write photolithography on a copper- cladded FR4 dielectric layer.
  • a calibration matrix is defined that expresses each force component as a linear combination of the signals generated by each half-bridge.
  • the objective is to formulate the calibration matrix [C] 3x4 that satisfies the following: where f x , f y , and z are the resolved forces; and s 1 — s 4 are the bridge outputs.
  • the sensor 12 was calibrated in a benchtop setting using precision weights of known mass, as shown in FIG. 13.
  • An example calibration curve for the -axis is shown in FIG. 14.
  • the on-axis signals are linear and dwarf the off-axis signals for a sufficiently pure measurement of the ⁇ -directional force.
  • the on-axis sensitivity is roughly 5 V/N, as designed.
  • the senor 12 is significantly more sensitive in the x- and y- axes than in the z- axis due to the mechanical amplification of the probe. Sensitivity matching can be achieved simply by shortening the length of the probe 22.
  • the Moore- Penrose pseudoinverse is computed to our overconstrained system of equations. This entails the use of a least-squares algorithm to numerically compute the pseudoinverse matrix, C, which is given in the following equation:
  • the sensor 12 is designed to withstand mechanical loads of up to 2 N so the gain can simply be adjusted to accommodate a higher operational range given the 5 V supply.
  • the root- mean-square (RMS) noise of the sensor 12 measured by integrating the power spectral density of a null signal, is roughly 8 mV (corresponding to 1.6 mN in the x- and /-axes). Note that, due to increased stiffness, the RMS noise is a factor of 10 higher in the ⁇ -direction (roughly, 16 mN).
  • Dynamic Response The dynamic response of the system is damped and of the second order, as shown in FIG. 15, where a step load of 50 mN was applied in the ⁇ -direction, and the response of the system was measured. As the sensor 12 is most compliant in the x- and /-directions, dynamic behavior in these axes will limit the operational bandwidth.
  • ⁇ 0:88
  • a tissue palpation experiment was simulated, wherein the sensor 12 was attached to the end effector of a 3-degree-of-freedom (DoF) linear stage equipped with a 3-DoF wrist to realize a 6-DoF micromanipulation platform.
  • An image of the test setup is shown in FIG 16.
  • Three ball-screw linear stages (ATSlOO-100, Aerotech, Pittsburgh, PA) are mounted orthogonally to create the 3-DoF linear stage.
  • the linear stages have 100 mm travel with a 0.5 ⁇ resolution and are connected to a control box (A3200 Npaq Drive Rack, Aerotech, Pittsburgh, PA) that runs an internal servo loop on the stages at 8 kHz.
  • the 3-DoF wrist has a gimbal design with three direct drive rotary joints.
  • Three 12-Watt 22-mm brushless DC motors (EC-max)
  • GUI graphical user interface
  • GUI User Interface library calls.
  • the GUI was programmed in C++ using the Qt application framework (Digia Pic, Helsinki, Finland).
  • a tissue analog was molded out of Ecoflex-0010 (Smooth-On), with high- stiffness intrusions (steel balls) embedded at different depths to simulate metastatic or cancerous tissue regimes.
  • Ecoflex-0010 Smooth-On
  • a solid block of Ecoflex-0010 was palpated with a spherical sensor probe.
  • the force profile generated by the sensor 12 was compared to an analytical force profile based on (1) a simple model assuming linear-elastic Hertzian contact mechanics and (2) a hyperelastic, neo-Hookean Mooney-Rivlin model given an empirical Young's
  • Modulus of E 30 kPa for the Ecoflex-0010.
  • the sensor 12 accurately captures the nonlinear hyperelastic behavior of the elastomer, as well as the hysteretic behavior that is not captured in the model.
  • the tissue analog was probed in an 8 x 8 grid with each subsequent probe separated from the previous probe by 9.2 mm.
  • Steel balls were buried at depths of 1 mm (ball 1), 3 mm (ball 2), and 5 mm (ball 3).
  • the indentation speed was 1 mm/ s, with a nominal indentation depth of 2 mm.
  • a normalized stiffness contour plot of the tissue, as measured by the sensor 12, was obtained; and the sensor 12 was able to accurately reconstruct the stiffness map of the tissue and localize high-stiffness intrusions, with the exception of the deepest intrusion, which was 5 mm deep (most likely due to the shallow indentation depth).
  • the monolithic fabrication of a fully integrated, highly sensitive triaxial sensor 12 is demonstrated using a pop-up MEMS approach.
  • the performance of the sensor 12 was tested both in benchtop calibration experiments as well as in a simulated tissue palpation task to demonstrate the sensor's efficacy at evaluating unknown forces with high precision.
  • Preliminary characterization methods have shown that the sensor 12 can resolve forces with ⁇ 1 mN resolution at a frequency of 20 Hz. Additionally, the sensor 12 was able to accurately detect subtle stiffness changes in a simulated tissue.
  • An embodiment of a pop-up laminate structure that can be distorted, flexed or folded can be fabricated by, for example, forming a five -layer composite with the following sequence of layers: rigid layer, adhesive layer, flexible layer, adhesive layer, rigid layer.
  • a thinner composite can be formed from a stacking of just a rigid layer, an adhesive layer, and a flexible layer, though this structure is not symmetric.
  • the rigid layers are machined to have gaps that correspond to fold lines, while the flexible layer is continuous, thereby providing a joint where the flexible layer extends across the gaps machined from the rigid layers.
  • the dimensions and feature sizes of the various apparatus described herein can be, e.g., 0.1 mm to 5 cm or, in more particular embodiments, 0.5 mm to 2 cm.
  • the devices described, below can be mass- fabricated by forming a plurality of the laminate structures across a large-area multi- layer laminate from which the individual devices can then be popped by, e.g., severing sacrificial bridges that joint the devices to the rest of the large-area laminate.
  • Characterization of the structure as being "super-planar” means taking multiple planar layers and selectively connecting them. An analogy here can be drawn to circuit boards, where electrical vias connect circuits on different layers.
  • the superplanar structure is made with "mechanical vias.” By stacking multiple planar layers, the range of achievable devices is greatly expanded.
  • the super-planar structure also enables features and components to be packed into the structure that would not fit if the device could only be made out of one planar sheet.
  • super-planar structures with mechanisms that operate normal to the plane can now be made with these techniques.
  • forming Sarrus linkages between planar layers is an advantageous strategy for designing an assembly mechanism/ scaffold. Other mechanisms can attach to the Sarrus links to effect the intended component rotations.
  • the multi-layer, super-planar structure can be fabricated via the following sequence of steps, which are further described, below: (1) machining each planar layer, (2) machining or patterning adhesives, (3) stacking and laminating the layers under conditions to effect bonding, (4) post-lamination machining of the multi-layer structure, (5) post-lamination treatment of the multi-layer structure, (6) freeing an assembly degree of freedom in each structure, (7) locking connections between structural members, (8) freeing any non-assembly degrees of freedom, and (9) separating finished parts from a scrap frame.
  • FIG. 24 A schematic representation of a fabrication process is provided in FIG. 24, illustrating how the basic operations of micromachining 101, lamination on dowel pins 50 and pick-and-place 102, folding 103, locking 104, and additional
  • micromachining 105 can be arranged to manufacture machines 106.
  • These assembly techniques can include the formation of folding joints 21, as illustrated in steps (a)-(d) of FIG. 25, wherein (a) features are first micro-machined 101 in individual material layers, and the resulting chips 13 are removed; (b) during lamination, dowel pins 50 pass through apertures 54 that align material layers while heat and pressure are applied; here, two rigid carbon-fiber layers 52 bonded to a flexible polyimide-film layer 36 with adhesive 34 form a five-layer laminate 15 referred to as a "linkage sub-laminate"; (c) micro-machining 101 cuts mechanical bridges that constrain individual elements, allowing the creation of articulated structures; and (d) a completed folding joint 21 is formed and removed from the surrounding scaffold 14.
  • Polyimide can have a flexural modulus of about 20 GPa; other materials ⁇ e.g., polymers) with a flexural modulus with a flexibility within about, e.g., 25%, 50% or 75% of this value (higher or lower) can alternatively be used for the flexible layer.
  • the rigid layers can be, e.g., less than half as flexible ⁇ i.e., more than twice as stiff) as the flexible layer.
  • the multi-layer structure is formed from a multitude of thin (1.5- ⁇ to about 150- ⁇ thick) layers of various materials.
  • These layers are laser micro-machined ⁇ e.g., by a diode-pumped solid-state pulsed laser) with desired features, usually cutting all the way through the layer to create individual planar structures.
  • Each layer is micro-machined so as to leave a unified (contiguous) part with robust connections to surrounding alignment holes.
  • the micro-machining can produce complex in-plane features with dimensions as small as 10 ⁇ .
  • many copies of the pop-up laminate device are formed on a laminate panel, and the machining process removes sufficient material to form each part and part feature, while leaving thin tabs to connect each device to the surrounding laminate; in this regard, the arrangement of devices in a laminate panel can be similar to that of a batch of circuit boards attached to a surrounding laminate structure by thin, easily breakable tabs.
  • each layer can be formed of a different material and can be machined and treated differently from each of the other layers.
  • Each layer can also advantageously be formed of a material that is sufficiently rigid, strong and tough to allow holes 54 for alignment pins 50 and other features to be machined into the layer to facilitate easy handling and to not distort (a) when placed into the layup and (b) when restrained by alignment pins 50.
  • layers that do not have the structural stability to support alignment features can nevertheless be used by attaching such layers, in bulk form, to a rigid frame that meets these objectives without introducing enough additional thickness to disturb the other layers or parts in the laminate.
  • a very thin polymer film ⁇ e.g., 2-5 microns thick
  • the thin polymer film Due to its thinness and insulating qualities, the thin polymer film is prone to wrinkling and electrostatic handling issues.
  • the thin polymer film can be lightly stretched, in bulk form, to a flat and controlled state and then bonded to a thin frame that is made, for example, of thin metal or fiberglass composite.
  • the thin polymer layer can be machined with the fine part features ⁇ e.g., tiny holes in the polymer at precise locations), and the alignment hole features can be machined into the frame material.
  • the device can be designed to mitigate thin-layer handling issues.
  • a part within the device can be designed such that all machining pertinent to a fragile layer is performed post-lamination; and, thus, this layer will not require precision alignment when put into the laminate, though the material is advantageously capable of being placed into the laminate sufficiently flat and extending over a sufficient area to cover the desired parts of the device.
  • bulk polymer films formed, e.g., of polyester, polyimide, etc.
  • metal sheets and foils formed, e.g., of stainless steel, spring steel, titanium, copper, invar (FeNi36), nickel-titanium alloy (nitinol), aluminum, etc.]; copper-clad laminates; carbon fiber and glass fiber composites; thermoplastic or thermoset adhesive films; ceramic sheets; etc.; can be laser machined to make the layers that are laminated to form the multi-layer structure.
  • the laser machining can be performed, e.g., with a 355-nm laser (from DPSS Lasers Inc. of Santa Clara, California) with a spot size of about 7 microns on materials with typical thicknesses of l-150- ⁇ , although thicker layers can be machined with such a laser, well.
  • this type of laser allows for very high resolution and an ability to machine almost any type of material.
  • Adhesion between layers is achieved by patterning adhesive onto one or both sides of a non-adhesive layer or by using free-standing adhesive layers ("bondplies") 34.
  • an intrinsically adhesive layer 34 e.g., in the form of a sheet of thermoplastic or thermoset film adhesive, or an adhesive laminate, such as a structural material layer with adhesive is pre-bonded to one or both sides.
  • the adhesive layer 34 is machined like the other layers.
  • Specific examples of sheets that can be used as the adhesive layer 34 include sheet adhesives used in making flex circuits ⁇ e.g., DuPont FR1500 adhesive sheet) or polyimide film 36 coated with FEP thermoplastic adhesive 34 on one or both sides.
  • Free-standing sheet adhesives can be acrylic-based for thermosets; alternatively, the adhesive can be thermoplastic, wherein the thermoplastic film can be formed of polyester, fluorinated ethylene propylene (or other fluoropolymer), polyamide, polyetheretherketone, liquid crystal polymer, thermoplastic polyimide, etc. Any of these adhesives can also be applied on one or both sides to a non-adhesive carrier.
  • a layer may serve both as a structural layer and as a thermoset adhesive 34— for example, liquid crystal polymer or thermoplastic polyimide.
  • a variety of wafer bonding techniques that do not require an adhesive may be employed, such as fusion bonding.
  • adhesive 34 is applied and patterned directly on a non-adhesive layer.
  • This technique can be used where, for example, the type of adhesive desired may not be amenable to being in a free-standing form.
  • Examples of such an adhesive 34 include solders, which are inherently inclined to form a very thin layer, or adhesives that are applied in liquid form (by spraying, stenciling, dipping, spin coating, etc.) and then b-stage cured and patterned. B-staged epoxy films are commonly available, but they usually cannot support themselves unless they are quite thick or reinforced with scrim.
  • the resulting bond can be a "tack bond," wherein the adhesive 34 is lightly cross-linked to an adjacent layer before laser micromachining with sufficient tack to hold it in place for subsequent machining and with sufficient strength to allow removal of the adhesive backing layer.
  • the tack bonding allows for creation of an "island” of adhesive 34 in a press layup that is not part of a contiguous piece, which offers a significant increase in capability.
  • Another reason for tacking the adhesive 34 to an adjacent structural layer is to allow for unsupported "islands” of adhesive 34 to be attached to another layer without having to establish a physical link from that desired adhesive patch to the surrounding "frame" of material containing the alignment features.
  • a photoimagable liquid adhesive such as benzocyclobutene
  • a photoimagable liquid adhesive can be applied in a thin layer, soft baked, and then patterned using lithography, leaving a selective pattern of adhesive.
  • Other photoimagable adhesives used in wafer bonding can also be used.
  • the adhesive 34 is patterned while initially tacked to its carrier film, aligned to the structural layer using pins 50, and then tacked to at least one adjoining layer in the layup with heat and pressure ⁇ e.g., at 200°C and 340 kPa for one hour).
  • the adhesive layer can be patterned by micro-machining it as a free sheet. Tack bonding can involve application of heat and pressure at a lower intensity and for less time than is required for a complete bond of the adhesive.
  • the adhesive film 34 can be tack bonded in bulk, and then machined using, for example, laser skiving/ etching.
  • use of this variation can be limited to contexts where the machining process does not damage the host layer. Both of these variations were tried using DuPont FR1500 adhesive sheet and laser skiving.
  • multi-layer laminate structure To form the multi-layer laminate structure, a multitude of these layers ⁇ e.g., up to 15 layers have been demonstrated) are ultrasonically cleaned and exposed to an oxygen plasma to promote bonding and aligned in a stack by passing several vertically oriented precision dowel pins 50 respectively through several alignment apertures 54 in each of the layers and by using a set of flat tooling plates with matching relief holes for the alignment pins 50.
  • other alignment techniques ⁇ e.g., optical alignment
  • All layers can be aligned and laminated together.
  • Linkages in the laminated layers can be planar (where all joint axes are parallel); or the joint axes can be non-parallel, allowing for non-planar linkages, such as spherical joints.
  • the final layup includes the following layers, which formed a pair of linkages ⁇ i.e., structures wherein flexible layers 36, formed, e.g. , of polyimide, are bonded to rigid segments 52, formed, e.g., of carbon, and extend across the gaps between the rigid segments 52), thereby enabling flexure of the rigid segments 52 relative to one another at the flexible layer 36 in the gaps between the rigid segments 52, wherein those exposed sections of the flexible layer 36 effectively serve as joints.
  • a pair of linkages ⁇ i.e., structures wherein flexible layers 36, formed, e.g. , of polyimide, are bonded to rigid segments 52, formed, e.g., of carbon, and extend across the gaps between the rigid segments 52), thereby enabling flexure of the rigid segments 52 relative to one another at the flexible layer 36 in the gaps between the rigid segments 52, wherein those exposed sections of the flexible layer 36 effectively serve as joints.
  • the choice of the flexible layers 36 which can be formed of a polymer— polyimide in this example— is based upon compatibility with the matrix resin in the carbon fiber.
  • the cure cycle can reach a maximum temperature of 177°C using a curing profile of four hours.
  • Polyimide film (available, e.g., as KAPTON film from E.I. du Pont de Nemours and Company), for example, has a sufficiently high service temperature (up to 400°C) to survive the curing step.
  • the polyimide film can have a thickness of, e.g., 7.5 ⁇ .
  • the rigid layers 52 in this embodiment are standard cured carbon fiber sheets ⁇ e.g., with three layers of unidirectional fibers, wherein the fiber layers are oriented at 0°, 90°, and 0° to provide thickness in two orthogonal directions), each sheet having a thickness of, e.g., 100 ⁇ .
  • Fifteen layers are used because the adhesive sheet 34 ⁇ e.g., in the form of a B-staged acrylic sheet adhesive, commercially available, e.g., as DuPont PYRALUX FR1500 acrylic sheets) in this embodiment is separate from each layer of structural material in the layup of this embodiment. Accordingly, the adhesive sheet 34 can be laser machined into a pattern differing from any structural layer, and aligned layups of many layers can be made. This capability enables the fabrication of parts with many linkage layers that are perfectly or near-perfectly aligned.
  • the layup can be cured in a heated press, autoclave, or other device that provides the atmosphere (or lack thereof), temperature, and pressure to achieve the bonding conditions required by the adhesive.
  • a heated press typically in a heated platen press
  • the layup can be cured in a heated press, autoclave, or other device that provides the atmosphere (or lack thereof), temperature, and pressure to achieve the bonding conditions required by the adhesive.
  • One embodiment of the curing process uses 50- 200 pounds-per-square-inch (psi) clamping pressure, 350°F (177°C) temperature, and two-hours cure time (optionally with temperature ramping control) to cure DuPont PYRALUX FR1500 acrylic sheets in a heated press with temperature, pressure, and atmosphere control.
  • the laminate is then machined ⁇ e.g., by severing tabs with a laser) to release the device(s) from a surrounding frame structure in the laminate.
  • the laminate is then machined ⁇ e.g., by severing tabs with a laser) to release the device(s) from a surrounding frame structure in the laminate.
  • additional machining that is not involved with freeing the device from the external frame (circumscribing the device in the laminate) is reserved for after lamination ⁇ e.g., post-lamination machining of a layer that is structurally weak or that, for some other reason, cannot be precisely aligned since the weak layer is better supported after lamination). 5) Post-Lamination Treatment
  • a post-lamination treatment can include plating or coating on an exposed layer; and/or the post-lamination treatment can include the addition of a material, such as solder paste, by silk screening or some other method, e.g., for the later joint "locking" step, as shown in FIGS. 26-28. Additional components may be attached to the laminate using a pick-and-place methodology. Pick-and-place operations can be used to insert discrete components into layups before press lamination.
  • a stimulus responsive material such as an electroactive material
  • a lead zirconate titanate piezoelectric plate is mounted on a spring clip in the carbon layer 52 and has been demonstrated to create a functional bimorph cantilever actuator within a device.
  • Press lamination and laser micro-machining can be conducted multiple times. For example, five layers can be laser micro-machined, then press laminated, then laser micro-machined again. Another three layers can be separately laser micro- machined, then press laminated, then laser micro-machined again. These two partial layups can then be press laminated together with a single adhesive layer between them, for a final layup of nine layers.
  • the resulting laminate can then be laser micro-machined and/ or scrap materials can be removed from the laminate to "release" functional components in each part.
  • the parts, as laminated, may unfold to have many actuated and passive mechanical degrees of freedom; though, in some embodiments, restraining these non-assembly degrees of freedom during the assembly folding process is
  • elements of a flexural linkage can be held in place (i.e., locked) ⁇ to prevent the linkages from flexing— by a rigid bar element alongside the elements or by a fixed tab forming an integral bridge between the elements and the surrounding structure.
  • a machining process e.g., punch die or laser cutting
  • the tabs or other features that restrain the assembly degree of freedom are severed.
  • the pop-up laminate can be a flat multi-layer laminate with limited three dimensional structure. Its components undergo a variety of assembly trajectories to realize the final fully three-dimensional topology. A co-fabricated mechanical transmission called an "assembly scaffold" couples all of these assembly trajectories into a single degree of freedom.
  • the pop-up laminate emerges from the manufacturing process as a three-degree-of-freedom machine, though internal mechanical connections eliminate these active degrees of freedom during assembly.
  • Assembly of the final device can be performed manually by external actuation, or assembly can happen spontaneously. Where assembly is spontaneous, if one or more of the layers is pre- strained, the relaxation of the pre-strained layers can lead to the assembly of the device as soon as the assembly degree of freedom is freed.
  • the layer that is pre- strained can be, for example, a patterned spring formed of spring steel or another spring-capable material, such as a superelastic nickel titanium alloy (nitinol) or an elastomer material that can survive the lamination conditions without annealing or degradation.
  • the dowel pins and the pin alignment holes in the pre-strained layer can be configured to maintain this tension when the pre-strained layer is in the stack through lamination.
  • the pre-strain can be in the form, for example, of tension or compression, though compression may require consideration of tendencies of linkages to buckle out of plane.
  • actuators can be built into the laminate to effect assembly.
  • a piezoelectric bending actuator, shape memory layer, or other type of actuator can be laminated into the structure as a pick-and-place component or inserted as an integral part of a layer in the layup; and the actuator can be actuated, e.g., by supplying electrical current or by changing temperature, to assemble the expanded, three-dimensional structure.
  • the assembly of all parts is actuated via a single assembly degree of freedom so that assembly proceeds in parallel for an entire panel, rather than part by part.
  • Assembly can be effected in several ways, depending on the design and complexity of the part.
  • a human operator can actuate the assembly degree of freedom manually or semi-automatically.
  • the assembly degree of freedom is in the form of a plate connected to a Sarrus linkage that is pulled up or pushed down.
  • Spherical joints or four-bar mechanisms can be attached to the Sarrus linkage, raising and folding other components into their three-dimensional position. Note that by having multiple rigid-flex planar layers and selective adhesion, complex mechanisms and collections of mechanisms can be released in the assembly step.
  • structural members After assembly into a final three-dimensional structure, structural members can be bonded together in a fixed configuration ⁇ i.e., locked, fixed or frozen).
  • adhesive can be manually applied to structural members and/ or joints, though this approach may not be ideal if many parts are being made.
  • adjacent members that have come together to form a locked joint can be automatically laser welded. If adjacent members 45 and 46 have metal pads 47 ⁇ e.g., formed of brass) on them, then wave or dip soldering can form strong filleted bonds 48 between the members, as shown in FIGS. 26-28.
  • solder paste can be applied, for example, by screen printing before assembly to the laminate; and then, after assembly, a re-flow step in a hot oven creates the bonds.
  • Other variations include the use of two-part adhesives, etc.
  • the pop-up laminate device includes brass pads 47 distributed across outer surfaces of its linkage sub-laminates, as shown in FIG. 26. After folding, pads on disparate links align into "bond points," in the form of either two pads 47 meeting at right angles, as shown in FIGS. 27 and 28, or three pads forming the corner of a cube.
  • the structure, held in its folded state, is submerged in a water-soluble flux ⁇ e.g., Superior Supersafe No. 30) and then pre-heated in an oven at 100°C for 10 minutes. It is then submerged in 260°C tin-lead eutectic solder for approximately 1 second. Finally, the structure is ultrasonically cleaned in distilled de-ionized water to remove the water-soluble flux residue. The result of this soldering process is the formation of solder fillets 48 at all bond points, as shown in FIG. 28, eliminating the assembly degree of freedom and locking all disparate machine components together.
  • Any non-assembly degrees of freedom in the part can be unlocked by removing any features ⁇ e.g., connected tabs) that restrain them via, e.g., laser machining. 10) Separating Parts from the Scrap Frame
  • the parts can be separated from the scrap frame ⁇ e.g., an outer frame to which the parts are connected by bridges of material) of the scaffold 14 by laser machining, punching, etc.
  • Layer sharing ⁇ e.g., an outer frame to which the parts are connected by bridges of material
  • two sub-layers can be thought of as sharing the same layer because they are non-overlapping and both engage with the same adhesive layer, e.g., glue, to bond with another layer.
  • adhesive layer e.g., glue
  • multiple layers occupy non-overlapping areas in the For example, four alignment pins 50 can be used.
  • a brass layer can cover half of the full area of the device, while a titanium layer can cover the other half.
  • the brass can be used to form solder pads 47, while the titanium can be used to form structural components.
  • Each sub-layer can engage with just two out of the four alignment pins 50 [i.e., two pins can engage with the brass sub-layer, while the two other pins can engage with the titanium sub-layer].
  • the layer can be split into many sub-layers if each sub-layer is engaged with enough alignment pins 50. For example, a single layer with six sub-layers can look like a map of New England, with each state made out of a different material, and with two alignment pins per state.
  • a second way of achieving layer sharing is by applying pressure to layers that are unsupported from below to bend the layers into the space below. Basically, if a large hole is cut in a thin layer, the application of pressure to the layer immediately above it (or below it) during lamination can be designed to warp and bend that adjacent layer around the edge of the hole, filling in the hole.
  • parameters for various properties or other values can be adjusted up or down by l/100 th , l/50 th , l/20 th , l/10 th , l/5 th , l/3 rd , 1/2, 2/3 rd , 3/4 th , 4/5 th , 9/10 th , 19/20 th , 49/50 th , 99/100 th , etc. (or up by a factor of 1, 2, 3, 4, 5, 6, 8, 10, 20, 50, 100, etc.), or by rounded-off approximations thereof, unless otherwise specified.

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Abstract

La présente invention porte sur un capteur de force multi-axe et monolithique qui peut se présenter sous la forme d'une structure stratifiée comprenant un échafaudage ; une pluralité de bras s'étendant à l'intérieur et de part et d'autre de l'échafaudage à des angles distincts, les bras comprenant une couche de support structurale, une couche de capteur comprenant un alliage de jauge de contrainte et une couche polymère flexible et électriquement isolante, prise en sandwich entre la couche de support structurale et la couche de capteur, dans une structure de stratifié multi-stratifié, monolithique ; des passages conducteurs de l'électricité positionnés pour fournir une tension par l'intermédiaire de l'alliage de jauge de contrainte dans les bras.
PCT/US2015/021683 2014-03-21 2015-03-20 Capteur de force multi-axe, monolithique WO2015143281A1 (fr)

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CN112236658B (zh) * 2018-06-14 2022-08-09 新东工业株式会社 应变体、应变体的制造方法、以及物理量测量传感器
CN109141709A (zh) * 2018-07-03 2019-01-04 合肥工业大学 一种分布式脚手架受力状态监测系统
CN114450153A (zh) * 2019-05-08 2022-05-06 沃扎诺有限公司 电子皮肤的基材
WO2020225565A1 (fr) * 2019-05-08 2020-11-12 Wootzano Limited Substrats destinés à des enveloppes électroniques
CN114270157A (zh) * 2019-08-30 2022-04-01 深圳纽迪瑞科技开发有限公司 力感应装置、力感应方法及设备

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