# US 9,517,030 B2 · Nonlinear system identification techniques and devices for discovering dynamic and static tissue properties

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,517,030 B2
- Document ID: US9517030B2
- Status: Granted
- Kind: B2
- Application number: 14/310,744
- Filed: 2014-06-20
- Published: 2015-02-19
- Granted: 2016-12-13
- Earliest claimed: 2009-09-01
- Assignees: Massachusetts Institute of Technology
- Applicants: Massachusetts Institute of Technology
- Inventors: Ian W. Hunter; Yi Chen
- Web page: https://patentgrep.com/patent/US9517030B2

## CPC

- A61B 5/103: Measuring devices for testing the shape, pattern, {colour,} size or movement of the body or parts thereof, for diagnostic purposes (measuring instruments specially adapted for dentistry A61C19/04)
- A01G 7/00: Botany in general
- A61B 5/0048: {Detecting, measuring or recording by applying mechanical forces or stimuli (A61B5/021, A61B5/4884 and A61B9/00 take precedence)}
- A61B 5/0053: {by applying pressure, e.g. compression, indentation, palpation, grasping, gauging}
- A61B 5/0055: {by applying suction}
- A61B 5/0057: {by applying motion other than vibrations, e.g. rolling, rubbing, applying a torque, tribometry}
- A61B 5/442: {Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment}
- A61B 5/6824: {Arm or wrist}
- A61B 9/00: Instruments for examination by percussion; Pleximeters
- G01N 3/24: by applying steady shearing forces (G01N3/26, G01N3/28 take precedence)
- G01N 3/40: Investigating hardness or rebound hardness
- G01N 2203/0069: Fatigue, creep, strain-stress relations or elastic constants
- G01N 2203/0218: Calculations based on experimental data
- G01N 2203/0246: Special simulation of "in situ" conditions, scale models or dummies
- G01N 2203/0278: Thin specimens
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A device for measuring a mechanical property of a tissue includes a probe configured to perturb the tissue with movement relative to a surface of the tissue, an actuator coupled to the probe to move the probe, a detector configured to measure a response of the tissue to the perturbation, and a controller coupled to the actuator and the detector. The controller drives the actuator using a stochastic sequence and determines the mechanical property of the tissue using the measured response received from the detector. The probe can be coupled to the tissue surface. The device can include a reference surface configured to contact the tissue surface. The probe may include a set of interchangeable heads, the set including a head for lateral movement of the probe and a head for perpendicular movement of the probe. The perturbation can include extension of the tissue with the probe or sliding the probe across the tissue surface and may also include indentation of the tissue with the probe. In some embodiments, the actuator includes a Lorentz force linear actuator. The mechanical property may be determined using non-linear stochastic system identification. The mechanical property may be indicative of, for example, tissue compliance and tissue elasticity. The device can further include a handle for manual application of the probe to the surface of the tissue and may include an accelerometer detecting an orientation of the probe. The device can be used to test skin tissue of an animal, plant tissue, such as fruit and vegetables, or any other biological tissue.

## Claims

### Claim 1

A device for measuring a mechanical property of a tissue, the device comprising:
a probe configured with a probe surface for contacting a surface of the tissue;
an actuator coupled to the probe for moving the probe laterally with respect to the surface of the tissue;
a detector configured to measure a response of the tissue to the lateral movement of the probe; and
a controller coupled to the actuator and the detector, the controller configured to move the probe laterally with respect to the surface of the tissue by driving the actuator using a stochastic sequence and determine the mechanical property of the tissue by using the measured response received from the detector when the stochastic sequence is driving the actuator.

### Claim 2 (depends on 1)

The device of claim 1, wherein the actuator is a Lorentz-force actuator.

### Claim 3 (depends on 1)

The device of claim 1, wherein the mechanical property is indicative of tissue compliance.

### Claim 4 (depends on 1)

The device of claim 1, wherein the mechanical property is indicative of tissue elasticity.

### Claim 5 (depends on 1)

The device of claim 1, wherein the detector comprises a force sensor for detecting force of the lateral movement.

### Claim 6 (depends on 5)

The device of claim 5, wherein the force sensor comprises a current sensor for detecting a current input to the actuator.

### Claim 7 (depends on 1)

The device of claim 1, wherein the detector comprises a position sensor for detecting displacement of the tissue surface.

### Claim 8 (depends on 1)

The device of claim 1, wherein the controller is configured to employ system identification to determine the mechanical property of the tissue from the measured response to the stochastic sequence driving the actuator.

### Claim 9 (depends on 8)

The device of claim 8, wherein said system identification is nonlinear system identification.

### Claim 10 (depends on 8)

The device of claim 8, wherein the stochastic sequence is a Gaussian input.

### Claim 11 (depends on 8)

The device of claim 8, wherein the stochastic sequence is a Brownian input.