# US 11,298,828 B2 · Calibration device, calibration method, and control device

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- Number: US 11,298,828 B2
- Document ID: US11298828B2
- Status: Granted
- Kind: B2
- Application number: 16/846,046
- Filed: 2020-04-10
- Published: 2020-07-30
- Granted: 2022-04-12
- Earliest claimed: 2017-11-02
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Takashi Nammoto; Koji Shiratsuchi
- Web page: https://patentgrep.com/patent/US11298828B2

## CPC

- B25J 9/1692: {Calibration of manipulator}
- B25J 9/161: {Hardware, e.g. neural networks, fuzzy logic, interfaces, processor}
- B25J 9/163: {learning, adaptive, model based, rule based expert control}
- B25J 9/1648: {non-linear control combined or not with linear control}
- B25J 9/1694: {characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion}
- B25J 13/085: {Force or torque sensors (B25J13/082, B25J13/084 take precedence)}
- B25J 19/02: Sensing devices
- G01D 5/00: Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable (G01D3/00 takes precedence; specially adapted for apparatus giving results other than momentary value of variable G01D1/00)
- G05B 19/4155: characterised by program execution, i.e. part program or machine function execution, e.g. selection of a program
- G05B 2219/39024: Calibration of manipulator
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

Disclosed is a calibration device including: a position information acquiring unit (101) for acquiring position information showing the position and the posture of control target equipment; a force information acquiring unit (102) for acquiring information about a force applied to the control target equipment from a detection result of a force sensor (5) disposed in the control target equipment; a first estimating unit (104) for estimating the force applied to the control target equipment from the acquired position information by using a physical model, to acquire estimated force information; and a second estimating unit (105) for estimating a linear or nonlinear model on the basis of the acquired position information, the acquired force information, and the acquired estimated force information.

## Claims

### Claim 1

A calibration device comprising:
processing circuitry to perform a process to:
acquire position information showing a position and a posture of control target equipment which constructs a device performing a force control and has at least either of a changing position and a changing posture; acquire information about a force applied to the control target equipment from a detection result of a force sensor disposed in the control target equipment;
estimate the force applied to the control target equipment from the position information acquired by using a physical model, to acquire estimated force information;
estimate a difference between estimated force information and force information using a linear or nonlinear model on a basis of the position information acquired, the force information acquired, and the estimated force information acquired when the control target equipment is not contact with other objects;
set the position information acquired as an input to a neural network and sets a difference between the estimated force information acquired and the force information acquired as a teaching signal for the neural network, and performs learning of the neural network, the neural network being utilized as the linear or nonlinear model,
wherein the physical model is separate from the linear or nonlinear model.

### Claim 2 (depends on 1)

The calibration device according to claim 1, wherein the process includes to convert the position information acquired into a continuous numeric representation including no discontinuity.

### Claim 3 (depends on 2)

The calibration device according to claim 2, wherein
the process converts the position information to vectors by performing rotation matrix calculation on the position information acquired.

### Claim 4 (depends on 1)

The calibration device according to claim 1, wherein the process acquires the position information and the force information about the control target equipment that performs uniform motion.

### Claim 5 (depends on 1)

The calibration device according to claim 1, wherein the process refers to information about the control target equipment, to estimate a difference between the estimated force information and the force information using the linear or nonlinear model.

### Claim 6 (depends on 5)

The calibration device according to claim 5, wherein
information regarding the control target equipment is a degree of wearing of end effector.

### Claim 7

A calibration method comprising:
acquiring position information showing a position and a posture of control target equipment;
acquiring information about a force applied to the control target equipment from a detection result of a force sensor disposed in the control target equipment;
estimating the force applied to the control target equipment from the acquired position information, to acquire estimated force information;
estimating a difference between estimated force information and force information using a linear or nonlinear model on a basis of the acquired position information, the acquired force information, and the acquired estimated force information, when control target equipment is not contact with other objects;
setting the position information acquired as an input to a neural network and setting a difference between the estimated force information and the force information as a teaching signal for the neural network; and
performing learning of the neural network, the neural network being utilized as the linear or nonlinear model,
wherein the physical model is separate from the linear or nonlinear model.

### Claim 8 (depends on 1)

A control device comprising:
processing circuitry to perform a process to:
calculate a control amount for the control target equipment from an output of a difference between estimated force information estimated using the linear or nonlinear model by the process of the calibration device according to claim 1, and force information, the estimated force information acquired, and the force information acquired; and
control the control target equipment on a basis of the control amount calculated.