US 2023/0408248 A1Published application

System and method for measuring mobility metrics of a joint using magnetometer-free inertial measurement units

AssigneeMuvr Labs, Inc.

InventorsPablo Abad, Prudhvi Tej Chinimilli, Ivan Vican

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Abstract

A method and a system include a first inertial measurement unit (IMU) is positioned on a first member of a joint and a second IMU is positioned on a second member of the joint, where the first IMU and the second IMU each lack a magnetometer unit. A processing device receives first IMU sensor data and second IMU sensor data. The first IMU sensor data is inputted into a quaternion computation algorithm (QCA) to compute a first quaternion. The first quaternion and the second IMU sensor data are inputted into the QCA to compute a one second quaternion, where the inputting of the first quaternion imposes yaw constraints. A calibration parameter algorithm determines a mobility metric of the joint based on the first and the second quaternions, and an orientation and position of the first IMU on the first member and of the second IMU on the second member.

Claims20

Dependent claims

A system, comprising:

at least one first inertial measurement unit (IMU) is positioned on a first member of a joint;
at least one second inertial measurement unit (IMU) is positioned on a second member of the joint;
wherein each of the at least one first IMU and the at least one second IMU lacks a magnetometer unit;
wherein the at least one first IMU and the at least one second IMU respectively output at least one first IMU sensor data and at least one second IMU sensor data;
at least one processing device configured to determine at least one mobility metric of the joint by executing programming instructions that cause the at least one processing device to:
receive, from the at least one first IMU, the at least one first IMU sensor data;
receive, from the at least one second IMU, the at least one second IMU sensor data;
input the at least one first IMU sensor data into a quaternion computation algorithm to compute at least one first quaternion;
input the at least one first quaternion and the at least one second IMU sensor data into the quaternion computation algorithm to compute at least one second quaternion;
wherein the inputting of the at least one first quaternion imposes a yaw constraint that reduces an uncertainty in:
at least one first yaw axis value in a coordinate frame of the at least one first IMU, and
at least one second yaw axis value in a coordinate frame of the at least one second IMU;
and
utilize a calibration parameter algorithm to determine the at least one mobility metric of the joint based on:
the at least one first quaternion,
the at least one second quaternion,
at least one first orientation and at least one first position of the at least one first IMU on the first member of the joint, and
at least one second orientation and at least one second position of the at least one second IMU on the second member of the joint.

15 more elements

A method, comprising:

receiving, by at least one processing device, from at least one first inertial measurement unit (IMU), at least one first IMU sensor data;
wherein the at least one first IMU is positioned on a first member of a joint;
receiving, by the at least one processing device, from at least one second inertial measurement unit (IMU), at least one second IMU sensor data;
wherein the at least one second IMU is positioned on a second member of the joint;
wherein each of the at least one first IMU and the at least one second IMU lacks a magnetometer unit;
wherein the at least one first IMU and the at least one second IMU respectively output the at least one first IMU sensor data and the at least one second IMU sensor data;
inputting, by the at least one processing device, the at least one first IMU sensor data into a quaternion computation algorithm to compute at least one first quaternion;
inputting, by the at least one processing device, the at least one first quaternion and the at least one second IMU sensor data into the quaternion computation algorithm to compute at least one second quaternion;
wherein the inputting of the at least one first quaternion imposes a yaw constraint that reduces an uncertainty in:
at least one first yaw axis value in a coordinate frame of the at least one first IMU and
at least one second yaw axis value in a coordinate frame of the at least one second IMU;
and
utilizing, by the at least one processing device, a calibration parameter algorithm to determine at least one mobility metric of the joint based on:
the at least one first quaternion,
the at least one second quaternion,
at least one first orientation and at least one first position of the at least one first IMU on the first member of the joint, and
at least one second orientation and at least one second position of the at least one second IMU on the second member of the joint.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/362,584Filed 31 Jul 2023
Priority: 20 Mar 2018
Published: 21 Dec 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G01B 7/30
Measuring arrangements characterised by the use of electric or magnetic techniques: for measuring angles or tapers; for testing the alignment of axes
G01C 21/166
By integrating acceleration or speed, i.e. inertial navigation: mechanical, construction or arrangement details of inertial navigation systems
G01C 21/18
By integrating acceleration or speed, i.e. inertial navigation: stabilised platforms, e.g. by gyroscope
G01C 25/005
Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass: initial alignment,…

Family

Application62/645,788Us provisional application · filed 20 Mar 2018
Application16/359,599Continuation · filed 20 Mar 2019
Application18/362,584Continuation
US 11,733,023 B2Related patent
US 2019/0293404 A1Published application
US 2023/0408248 A1This patent

From the US filing history. Foreign family members aren’t listed.

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