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AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsFrank A. Leban, Gordon G. Parker
Estimating the term…
The present invention is typically embodied to exert active control of two same-shipboard cranes performing joint lifting of a payload. Sensory signals indicative of ship motion, and of luff angle and hoist line length of both cranes, are transmitted to a computer. The sensory signals are processed by the computer using a ship motion cancellation algorithm, which solves for values of the respective luff angles and hoist line lengths of both cranes, such values achieving static equilibrium (e.g., zero motion horizontally, vertically, and rotationally in the same vertical geometric plane) of the suspended payload. Inverse kinematic control signals in accordance with the mathematical (e.g., minimum norm) solutions are transmitted by the computer to respective luff angle actuators and hoist line length actuators of both cranes so that the suspended payload tends toward steadiness. Inventive control thus acts on a continual basis to significantly reduce pendulation during the two-crane lifting operation.
An active control method for facilitating joint lifting of a load by plural cranes situated onboard the same marine vessel, the active control method comprising sensing geometric parameters of said cranes, sensing motion of said marine vessel, determining solutions for said geometric parameters to approximate a static equilibrium condition preventing pendulation of said load, and adjusting said geometric parameters in accordance with the determined said solutions, wherein said sensing of said geometric parameters, said sensing of said motion of said marine vessel, said determining of said solutions for said geometric parameters, and said adjusting of said geometric parameters are performed on a continual basis during said joint lifting of said load by said cranes, said solutions for said geometric parameters being determined repeatedly so as to continually update said approximations of said static equilibrium condition preventing pendulation of said load, the active control method thereby, on a continual basis, coordinating said joint lifting of said load by said cranes so as to at least substantially prevent pendulation of said load that is caused by said motion of said marine vessel during said joint lifting of said load by said cranes.
An apparatus comprising a computer configured to perform an active control method for facilitating joint lifting of a load by plural cranes situated onboard the same marine vessel, the method including receiving from said cranes sensory signals indicative of geometric parameters of said cranes, receiving from said marine vessel sensory signals indicative of motion of said marine vessel, calculating solutions for said geometric parameters to approximate a static equilibrium condition preventing pendulation of said load, and transmitting to said cranes control signals for adjusting said geometric parameters in accordance with the calculated said solutions, wherein said receiving of said sensory signals indicative of said geometric parameters, said receiving of said sensory signals indicative of said motion of said marine vessel, said calculating of said solutions for said geometric parameters, and said transmitting of said control signals for adjusting said geometric parameters are performed on a continual basis during said joint lifting of said load by said cranes, said solutions for said geometric parameters being calculated repeatedly so as to continually update said approximations of said static equilibrium condition preventing pendulation of said load, said computer thereby, on a continual basis, coordinating said joint lifting of said load by said cranes so as to at least substantially prevent pendulation of said load that is caused by said motion of said marine vessel during said joint lifting of said load by said cranes.
A computer program product for exerting active control with respect to plural cranes situated onboard the same marine vessel, said active control facilitating joint lifting by said cranes of a load, the computer program product comprising a non-transitory computer-readable storage medium having computer-readable program-code portions stored therein, the computer-readable program-code portions including:
Dependencies are inferred from the claim text.