Coordinate Input Device Noise Filtering via Moving Average
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Solution Overview
Problem
Coordinate input devices face challenges in accurately stopping a cursor at an intended position due to residual noise caused by hysteresis characteristics, which prevent operators from performing intended operations effectively.
Innovation Solution
A coordinate input device with strain sensors and a control unit that calculates moving average values from output data, setting the output to 0 when predetermined conditions are met to mitigate the influence of residual noise, thereby improving operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the stick-type operation unit is used for coordinate input, then the operation flexibility is improved, but residual noise occurs after finger separation causing cursor positioning errors
Solution Approach 1:
The control unit performs preliminary judgment by comparing the absolute value of load data with a predetermined threshold before processing coordinate data. This preliminary action filters out residual noise that occurs after finger separation, preventing erroneous cursor movements while maintaining operation flexibility during normal use
Solution Approach 2:
The invention changes the parameter processing approach by introducing a threshold value for load data magnitude. When the load data absolute value falls below this threshold, the system treats it as noise and outputs zero instead of processing it as valid coordinate input, thereby eliminating cursor positioning errors caused by residual noise
2Speed
If the load data is directly processed without filtering, then the response speed is improved, but residual noise causes cursor overrun and positioning errors
Solution Approach 1:
The invention introduces a threshold parameter for load data magnitude. By comparing the absolute value of load data against this predetermined threshold, the system quickly identifies and filters residual noise without requiring complex processing, thus maintaining fast cursor response while eliminating positioning errors
3Measurement precision
If the threshold value is set low to filter noise, then the positioning accuracy is improved, but normal small operations may be blocked
Solution Approach 1:
The invention optimizes the threshold parameter value to strike a balance between noise filtering and operation responsiveness. The threshold is set to be sufficiently high to allow normal small operations to pass through, yet low enough to effectively filter residual noise, achieving both accurate positioning and responsive 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 effectively reduces the impact of residual noise, allowing for stable cursor positioning and enhanced operability by distinguishing between actual and noise-induced signals.
Implementation Method 1
strain sensors that output data corresponding to an operation amount of the operation unit
Data Source
AI summary
A coordinate input device includes an operation unit that is provided so as to be operated, strain sensors that output data corresponding to an operation amount of the operation unit, and a control unit. The control unit performs the count corresponding to the increase or decrease of speed data that is obtained by converting data sequentially output from the strain sensors, and generates counted count values or coordinate data calculated from the count values. The control unit calculates a moving average value from the count values that are sequentially output every predetermined time. When the moving average value satisfies predetermined conditions, the control unit regards that the operation of the operation unit is cancelled, and stops the output of the coordinate data or outputs 0 as the count value.