Stylus Autonomous Position Calculation via Inertial Sensor
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Solution Overview
Problem
Existing stylus systems face high power consumption when monitoring the positional relationship with an electronic device during wireless communication, and they cannot autonomously calculate the relative position between the stylus and the device.
Innovation Solution
A stylus equipped with a pen sensor, inertial sensor, and processor that detects pen events, measures movement, and calculates coordinate conversions from the pen coordinate system to the device coordinate system using pairs of coordinate values to determine conversion parameters, allowing autonomous position calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireless communication is performed in both directions between the stylus and the electronic device to monitor the positional relationship, then the positional accuracy is improved, but the power consumption on the stylus side increases
Solution Approach 1:
The system divides the position detection function into two parts: the electronic device performs active detection by transmitting electromagnetic signals and receiving responses, while the stylus performs passive detection by measuring the electromagnetic field directly. This segmentation allows the stylus to obtain position information without continuous two-way communication, reducing its power consumption while maintaining positional accuracy.
Solution Approach 2:
The electromagnetic field generated by the electronic device serves as an intermediary carrier of position information. The stylus detects its position by measuring the electromagnetic field strength and characteristics without needing to actively communicate with the device, thus achieving accurate position detection with minimal power consumption.
2Use of energy by moving object
If the stylus autonomously calculates the relative position using inertial sensors and coordinate conversion, then the power consumption is reduced, but the device complexity increases
Solution Approach 1:
The inertial sensor unit serves multiple functions: it detects the stylus's movement in three-dimensional space, provides data for coordinate system conversion, and enables autonomous position calculation. By making the inertial sensor multi-functional, the system reduces power consumption without requiring additional dedicated components, thus limiting the increase in device complexity.
Solution Approach 2:
The stylus autonomously calculates its own position relative to the electronic device by using data from its own inertial sensor and electromagnetic field measurements. This self-service approach eliminates the need for the stylus to continuously receive position information from the device through wireless communication, reducing power consumption while the integration of calculation functions into the existing processor minimizes the increase in device complexity.
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
Enables autonomous calculation of the relative position between the stylus and the electronic device, reducing power consumption and improving operational efficiency.
Implementation Method 1
an inertial sensor which, in operation, measures an amount of movement of the stylus in a pen coordinate system
Data Source
AI summary
A stylus includes a processor that acquires first coordinate values in a pen coordinate system at an occurrence position of a pen event detected by a pen sensor and acquires second coordinate values in a device coordinate system at the occurrence position of the pen event. The processor uses a plurality of sets of coordinate value pairs to determine conversion parameters for converting coordinates from the pen coordinate system into the device coordinate system and uses the determined conversion parameters and a measured amount of movement of the stylus to calculate coordinate values of the stylus in the device coordinate system.