Motion Tracking Solutions Using a Self Correcting Three Sensor Architecture
OwnerJohn Baker, Remigio Peralesinventors
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Abstract
A system of sensors including 1) an accelerometer, 2) a magnetometer, and 3) a gyroscope, combined with a zero crossing error correction algorithm, as well as a method of using those sensors with the zero crossing error correction algorithm, for orientation motion tracking applications, including sports and athletics training, animation for motion picture and computer gaming industry, 3D joysticks, and peripherals for computer gaming industry, as well as medical and health diagnosis and monitoring systems.
Claims39
A system for tracking motion and calculating error corrected orientations, comprising:
- A sensor node, which comprises an accelerometer, gyroscope and magnetometer, and which is attached to a segment of a subject that is expected to move;
- Means for instantaneous raw sensor data to pass from the sensor node to a microcontroller unit (MCU);
- An MCU which receives raw sensor data from the sensor nodes;
- Means for performing data processing and/or analysis on the sensor data, computing the orientation of the sensor node as well as for applying the zero crossing error correction algorithm to the computed orientation to correct errors;
- and
- Means for providing power to all components of the system.
A method of tracking motion and calculating error corrected orientations, comprising the steps of:
- Aligning the axes of an accelerometer, gyroscope, and magnetometer on a sensor node;
- Attaching a sensor node to the subject or segment of a subject to be tracked;
- Capturing instantaneous data over time from the accelerometer, gyroscope, and magnetometer comprising the sensor node;
- Transferring all or a portion of the raw sensor data in sets over time from the sensor node to a processor;
- Calculating with a processor the non-corrected orientation of the sensor node using each set of raw sensor data;
- Monitoring the accelerometer data with a processor and identifying points in time where the magnitude of the acceleration is below a predefined threshold. These points in time are defined as the zero crossings;
- and
- Applying with a processor the zero crossing error correction algorithm to each calculated orientation.
A method of calibrating a magnetometer to correct for the presence of ferrous or magnetic materials in close proximity to the sensor node which produce a local magnetic field. Calibration steps are comprised of the following:
- Measuring the direction of the geomagnetic field with a magnetometer on a sensor node, while the sensor node is isolated from any other ferrous magnetic material;
- Attaching the sensor node to the ferrous or magnetic material, while keeping track of gyroscope data to ascertain the position of the sensor node;
- Using the known data of the geomagnetic field and orientation of the sensor node and data from the magnetometer measuring total magnetic field to calculate the local magnetic field due to the ferrous or magnetic material;
- and
- Storing local magnetic field data to be subtracted from future magnetometer readings.
Dependencies are inferred from the claim text.