Pointing Device Orientation Using Magnetometer and Inertial Sensor
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Solution Overview
Problem
Three-dimensional pointing and control devices suffer from precision issues due to accumulating offsets and noise in acceleration and angular velocity signals, requiring periodic recalibration and leading to sudden deviations in control operations.
Innovation Solution
A pointing and control device that combines a magnetometer and an inertial sensor with a processor to determine orientation in an absolute reference system, using signals from the Earth's gravitational and magnetic fields, eliminating the need for signal integration and reducing noise-related errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If signal integration is used to determine position and direction from acceleration and angular velocity signals, then control freedom and three-dimensional capability are improved, but measurement precision deteriorates due to accumulating offsets and noise
Solution Approach 1:
The patent introduces magnetic field signals as an intermediary reference system to resolve the accumulation error problem. Instead of directly integrating acceleration and angular velocity signals, the system uses magnetometer measurements of the Earth's magnetic field as a stable reference frame to periodically correct and reset the integrated orientation values, thereby eliminating noise accumulation while preserving three-dimensional control capability
Solution Approach 2:
The system implements feedback by continuously comparing the integrated orientation from inertial sensors with the orientation derived from magnetic field measurements. This feedback mechanism allows periodic correction of accumulated errors without interrupting the three-dimensional control operations, maintaining both versatility and precision
2Measurement precision
If periodic recalibration operations are performed to eliminate errors, then measurement precision is temporarily improved, but productivity deteriorates due to control interruptions
Solution Approach 1:
The patent enables continuous control operations by performing recalibration in the background using magnetic field measurements without interrupting the pointing device functionality. The system continuously integrates inertial sensor data while periodically correcting accumulated errors using magnetic reference data, ensuring uninterrupted three-dimensional control
Solution Approach 2:
The system performs preliminary error correction by continuously tracking magnetic field orientation and using it to pre-correct accumulated integration errors before they significantly degrade precision. This proactive approach eliminates the need for disruptive recalibration operations
3Adaptability or versatility
If integration operations are performed to determine position from acceleration signals, then device functionality is improved, but reliability deteriorates due to sudden deviations and error accumulation
Solution Approach 1:
Magnetic field measurements serve as a reliable intermediary reference that does not suffer from integration error accumulation. The system uses this stable magnetic reference to periodically reset and correct the integrated orientation values, eliminating sudden deviations while maintaining full pointing device functionality
Solution Approach 2:
The system applies preliminary anti-action by using magnetic field orientation data to counteract and correct accumulated integration errors before they cause sudden deviations or loss of control stability. This preventive correction mechanism ensures continuous reliable operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides stable and precise control operations by determining orientation directly, reducing the impact of noise and offsets, and eliminating the need for recalibration, thereby enhancing the accuracy and reliability of three-dimensional control devices.
Implementation Method 1
an inertial sensor fixed to the body for supplying first signals correlated to the orientation of the body with respect to a gravitational field acting on the inertial sensor
Implementation Method 2
a magnetometer fixed to the body for supplying second signals correlated to the orientation of the body with respect to the Earth's magnetic field acting on the magnetometer
Data Source
AI summary
A pointing and control device for a computer system, the device having a body that can be maneuvered by a user; and an inertial sensor fixed to the body for supplying first signals correlated to the orientation of the body with respect to a gravitational field acting on the inertial sensor. The device moreover includes a magnetometer fixed to the body for supplying second signals correlated to the orientation of the body with respect to the Earth's magnetic field acting on the magnetometer and processing modules for determining an orientation of the body in an absolute reference system, fixed with respect to the Earth's magnetic field and gravitational field on the basis of the first signals and second signals.