Method and apparatus for sensing the orientation of a mechanical actuator
First Claim
1. For a linear actuator of the type including a stationary portion and a moveable connector, a method for determining the position of the connector relative to the stationary portion comprising the steps of:
- generating electromagnetic (EM) bursts;
transmitting the EM bursts from one of the stationary portion and the moveable connector;
receiving the EM bursts at the other of the stationary portion and the moveable connector;
generating a timing signal representative of the time for the EM bursts to travel between the stationary portion and the moveable connector; and
converting the timing signal into a position signal representative of the distance between the stationary portion and the moveable connector.
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0 Petitions
Accused Products
Abstract
A system for determining the extended length or orientation of a hydraulic actuator, or of an implement or joint, is disclosed herein. Electromagnetic (EM) bursts such as ultra-wideband or frequency pulses are generated and applied to a transmitter unit attached to a stationary or moveable portion of the actuator. The EM bursts are launched by the transmitter toward a receiver located on the other of the stationary or moveable portion of the actuator. The time for the EM bursts to travel between the associated antennas of the transmitter and the receiver is determined and converted into a position signal representing the distance therebetween.
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Citations
31 Claims
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1. For a linear actuator of the type including a stationary portion and a moveable connector, a method for determining the position of the connector relative to the stationary portion comprising the steps of:
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generating electromagnetic (EM) bursts; transmitting the EM bursts from one of the stationary portion and the moveable connector; receiving the EM bursts at the other of the stationary portion and the moveable connector; generating a timing signal representative of the time for the EM bursts to travel between the stationary portion and the moveable connector; and converting the timing signal into a position signal representative of the distance between the stationary portion and the moveable connector. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An actuator arrangement comprising:
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a stationary portion; a connector moveable relative to the stationary portion; a transmitter configured to transmit signals, the transmitter being coupled to one of the connector and the stationary portion; and a receiver configured to receive the signals, the receiver being coupled to the other of the connector and the stationary portion. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A hydraulic cylinder assembly comprising:
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a cylinder having a closed first end and a second end having a sealed opening; a piston located within the cylinder; a piston rod having a first rod end and a second rod end, the piston being attached to the first rod end and the piston rod being slidably positioned within the sealed opening; a first hydraulic fluid port located at the closed first end of the cylinder to permit fluid to flow in and out of the cylinder; a second hydraulic fluid port located at the second end of the cylinder to permit fluid to flow in and out of the cylinder; a transmitter configured to transmit signals, the transmitter being coupled to one of the second rod end and the second end of the cylinder; and a receiver configured to receive the signals, the receiver being coupled to the other of the second rod end and the second end of the cylinder. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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31. An electrohydraulic control system for controlling the positions of an implement, comprising:
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an input device configured to generate command signals representative of a commanded position of the implement; a hydraulic actuator coupled to the implement and including a cylinder housing, a piston moveable within the cylinder housing, and a piston rod attached to the piston, whereby the piston rod moves with the piston; a source of pressurized hydraulic fluid; a valve assembly coupled between the actuator and the source, the valve assembly configured to control the flow of hydraulic fluid between the actuator and the source in response to control signals; a generator for generating EM bursts; a transmitter coupled to one of the piston rod and the cylinder housing, the transmitter configured to launch the EM bursts in response to a transmit timing signal; a receiver coupled to the other of the piston rod and the cylinder housing, the receiver configured to generate a pulse detect signal and sample the EM bursts at times which are delayed relative to the times the transmitter transmits the EM bursts; a timing circuit configured to generate a timing signal representative of the time for the EM bursts to travel from the transmitter to the receiver; a position signal generation circuit configured to convert the timing signal into a position signal representative of the position of the piston within the cylinder housing; and a control circuit coupled to the input device, the valve assembly and the position signal generation circuit, the control circuit configured to generate the control signals based upon the command signals and the position signal, and to apply the control signals to the valve assembly.
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Specification