Tactile sensing method and system
First Claim
1. A method for detecting tactile information on touch force acting on measurement points, based on outputs from bridge circuits constituted by strain gauges adhered to each measurement point, comprising:
- generating a composite sine wave signal that contains sine wave components having different frequencies;
applying the composite sine wave signal to each bridge circuit via a bandpass filter to apply to each bridge circuit a sine wave signal of a predetermined single frequency;
adding outputs from each bridge circuit to generate a sum output;
from the sum output, utilizing trigonometric function orthogonality to obtain at least touch force of touch force and touch direction acting on each measurement point;
comparing voltage amplitude measured at each measurement point to a reference voltage preset for each measurement point and adjusting the voltage amplitude of the sine wave signal of each frequency applied to the bridge circuit of each measurement point to control the gain of the bridge circuit of each measurement point to reduce any difference between measured and reference voltages.
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Accused Products
Abstract
A system for detecting tactile information includes strain-gauge touch sensors and a controller. Based on the sum output from each of tough-sensor sensor units, an analyzer in the controller calculates touch force Fi(t) at each measurement point. An automatic gain control adjusts the voltage amplitude Ai(t) of a sine wave of frequency fi applied to the sensor units at each measurement point to bring the voltage amplitude measured at each measurement point in line with a target voltage. The adjusted voltage Ai(t) is applied to the bandpass filter with a composite sine wave y(t) which includes sine waves of each frequency corresponding to the adjusted voltage amplitude Ai(t). This makes it possible to reduce the number of lines between the controller and touch sensors that includes numerous measurement points, and enables the gain of the touch sensors constituted by strain gauges to be controlled within an appropriate range.
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Citations
2 Claims
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1. A method for detecting tactile information on touch force acting on measurement points, based on outputs from bridge circuits constituted by strain gauges adhered to each measurement point, comprising:
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generating a composite sine wave signal that contains sine wave components having different frequencies; applying the composite sine wave signal to each bridge circuit via a bandpass filter to apply to each bridge circuit a sine wave signal of a predetermined single frequency; adding outputs from each bridge circuit to generate a sum output; from the sum output, utilizing trigonometric function orthogonality to obtain at least touch force of touch force and touch direction acting on each measurement point; comparing voltage amplitude measured at each measurement point to a reference voltage preset for each measurement point and adjusting the voltage amplitude of the sine wave signal of each frequency applied to the bridge circuit of each measurement point to control the gain of the bridge circuit of each measurement point to reduce any difference between measured and reference voltages. - View Dependent Claims (2)
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Specification