Hydraulic piston position sensor signal processing
First Claim
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1. An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:
- an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod;
a sliding member slidably coupled to the piston, the sliding member configured to cause a partial reflection of the microwave pulse;
a fudicial member coupled to a proximal end of the antenna rod and configured to generate a fudicial reference reflection in response to a microwave pulse;
microwave transceiver circuitry coupled to the antenna rod configured to generate and receive microwave pulses; and
computation circuitry configured to calculate piston position;
wherein an amplitude of a fudicial reference reflection is related to piston position when the piston is proximate the fudicial member and the computation circuitry calculates piston position based upon the amplitude of the fudicial reference pulse when the piston is proximate the fudicial member.
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Abstract
A piston position in a cylinder of a hydraulic assembly is measured using microwave pulses. The microwave pulses are launched along a conductor coupled to the piston or cylinder. A sliding member is slidably coupled to the conductor and moves with the piston or cylinder. Position is determined as a function of a reflection from the end of the conductor and the sliding member. Various aspects include signal processing, fudicial pulse identification control and input/output circuitry, and a three conductor configuration.
137 Citations
46 Claims
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1. An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:
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an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod;
a sliding member slidably coupled to the piston, the sliding member configured to cause a partial reflection of the microwave pulse;
a fudicial member coupled to a proximal end of the antenna rod and configured to generate a fudicial reference reflection in response to a microwave pulse;
microwave transceiver circuitry coupled to the antenna rod configured to generate and receive microwave pulses; and
computation circuitry configured to calculate piston position;
wherein an amplitude of a fudicial reference reflection is related to piston position when the piston is proximate the fudicial member and the computation circuitry calculates piston position based upon the amplitude of the fudicial reference pulse when the piston is proximate the fudicial member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:
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an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod, the antenna rod comprising a reference conductor at least partially within an outer conductor;
a sliding member slidably coupled to the outer conductor of the antenna rod and slidable as the piston moves within the cylinder to cause a partial reflection of the microwave pulse;
microwave transceiver circuitry coupled to the antenna rod configured to generate and receive microwave pulses; and
computation circuitry configured to calculate piston position as a function of reflected microwave pulses carried on the outer conductor and reflected microwave pulses carried on the reference conductor of the antenna rod. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:
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an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod;
a sliding member slidably coupled to the piston, the sliding member configured to cause a partial reflection of the microwave pulse;
a fudicial member coupled to a proximal end of the antenna rod configured to generate a fudicial reference reflection in response to a microwave pulse;
microwave transceiver circuitry coupled to the antenna rod configured to generate and receive microwave pulses;
computation circuitry configured to calculate a piston position as a function of the partial reflection of the microwave pulse from the sliding member; and
control circuitry configured to provide a control signal to a hydraulic actuator in response to a command input and the piston position, the control signal a function of at least one of an integral or derivative of the piston position. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:
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an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod;
a sliding member slidably coupled to the piston, the sliding member configured to cause a partial reflection of the microwave pulse;
a fudicial member coupled to a proximal end of the antenna rod configured to generate a fudicial reference reflection in response to a microwave pulse;
microwave transceiver circuitry coupled to the antenna rod configured to generate and receive microwave pulses;
computation circuitry configured to calculate a piston position as a function of the partial reflection of the microwave pulse from the sliding member; and
control circuitry including an input/output (I/O) connection having a plurality of programmable functions. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:
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an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod;
a sliding member slidably coupled to the piston, the sliding member configured to cause a partial reflection of the microwave pulse;
a fudicial member coupled to a proximal end of the antenna rod configured to generate a fudicial reference reflection in response to a microwave pulse;
microwave transceiver circuitry coupled to the antenna rod configured to generate and receive microwave pulses; and
computation circuitry configured to calculate piston position as a function of a time delay in microwave pulses reflected from the sliding member, the computation circuitry including a digital computation device configured to digitally process a signal received from the microwave transceiver. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46)
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Specification