Load cell assembly with linearization and common mode discrimination of complementary force-responsive signals
First Claim
1. A load cell assembly for generating a force value indicative of an applied force, the load cell assembly comprising:
- a load cell body adapted to receive the applied force;
first and second sensing means, coupled to the load cell body, for respectively providing first and second sensed signals which react in a complementary manner in response to the applied force on the load cell body;
means for sampling the first and second sensed signals at predetermined intervals of time to produce first and second change values representative of changes in the values of the first and second sensed signals over such predetermined time interval, each of said first and second change values having a magnitude value and a direction of change;
means for determining when the directions of change in the first and second change values are different; and
force calculating means, responsive to the determining means, for calculating the force value of the applied force from the magnitudes of the first and second change values.
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Accused Products
Abstract
A load cell assembly includes a load cell body having a pair of sensors mounted therein which provide complementary output signals in response to a force applied to the load cell body. A linearization and common mode discrimination routine analyzes changes in the sensor outputs and characterizes the changes as being either primarily due to applied force or primarily due to common mode effects. A force value, indicative of the applied force on the load cell body, is updated only for changes in the sensor outputs which are primarily due to applied force. However, changes which are primarily due to common mode effects are not incorporated into force value calculations, whereby common mode effects are rejected.
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Citations
33 Claims
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1. A load cell assembly for generating a force value indicative of an applied force, the load cell assembly comprising:
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a load cell body adapted to receive the applied force; first and second sensing means, coupled to the load cell body, for respectively providing first and second sensed signals which react in a complementary manner in response to the applied force on the load cell body; means for sampling the first and second sensed signals at predetermined intervals of time to produce first and second change values representative of changes in the values of the first and second sensed signals over such predetermined time interval, each of said first and second change values having a magnitude value and a direction of change; means for determining when the directions of change in the first and second change values are different; and force calculating means, responsive to the determining means, for calculating the force value of the applied force from the magnitudes of the first and second change values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A driver for generating a force value indicative of a force that is applied to a load cell assembly of the type including first and second force sensors which have complementary sensitivity to the applied force, the driver comprising:
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first and second sampling means, coupled to the first and second force sensors, for periodically providing first and second sensed values, respectively, each of said first and second sensed values having a magnitude value and a direction of change; means for determining when the directions of change in the first and second sensed values are different; and force accumulating means, responsive to the determining means, for calculating the force value of the applied force from the magnitudes of the first and second change values. - View Dependent Claims (20, 21, 22, 23)
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24. A method for generating a force value indicative of an applied force in a load cell assembly of the type including first and second force sensors mounted in a load cell body to exhibit complementary sensitivity to the applied force, comprising:
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driving the first and second force sensors to generate first and second sensed signals, respectively; calculating first and second change values representative of respective changes in the first and second sensed signals over a predetermined time period, each of said first and second change values having a magnitude value and a direction of change; determining when the directions of change in the first and second change values are different; and calculating the force value of the applied force from the magnitudes of the first and second change values. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification