US2010324719A1PendingUtilityA1
Method and system for damping sloshing molten metal
Est. expiryMay 16, 2028(~1.8 yrs left)· nominal 20-yr term from priority
B22D 47/02
52
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Claims
Abstract
The disclosed method is a control to suppress sloshing in a ladle of a pouring device and a mold caused by their movements. A plurality of flasks, each of which contains a conveyed mold, is arranged linearly between an electric pusher-cylinder and an electric cushion-cylinder. In the method, a first natural frequency of the molten metal in the ladle is calculated based on a predetermined relationship between the weight and the natural frequency for the molten metal in the ladle, and the measured weight of the molten metal in said ladle. Also, a second natural frequency of the molten metal in said mold is calculated based on a predetermined relationship between the weight and the natural frequency for the molten metal in the mold, and the measured weight of the molten metal in the mold. The first and second natural frequencies are entered in a filtering circuit to modify a velocity waveform of the movement of conveying the flasks such that the modified velocity waveform does not include the first and second natural frequencies. The electric pusher-cylinder and the electric cushion-cylinder are driven such that the velocity waveform of the movement of conveying the flasks is said modified velocity waveform.
Claims
exact text as granted — not AI-modified1 . A method of suppressing sloshing in a casting line, wherein said casting line includes:
a conveying line in which an electric pusher-cylinder is located at one end of the conveying line for intermittently pushing out a plurality of flasks, wherein each flask contains a mold, one by one, and an electric cushion-cylinder is located at the other end of said conveying line and opposed to said electric pusher-cylinder to receive and cushion a group of said pushed flasks such that said conveying line that conveys said plurality of flasks is arranged linearly between said electric pusher-cylinder and said electric cushion-cylinder; and an automatic pouring device that has a ladle for containing molten metal and that can be moved in synchronization with the flask on the conveying line, to pour the molten metal into the mold by tilting said ladle; said method controlling said electric pusher-cylinder and said electric cushion-cylinder by using a controller having filtering means such that the sloshing that occurs in the molten metal is suppressed when said ladle and said mold move by a distance corresponding to one flask, said method comprising: calculating a first natural frequency of the molten metal in said ladle based on a predetermined relationship between the weight and the natural frequency for the molten metal in said ladle, and the measured weight of the molten metal in said ladle, and calculating a second natural frequency of the molten metal in said mold based on a predetermined relationship between the weight and the natural frequency for the molten metal in said mold, and the measured weight of the molten metal in said mold; entering the first and second natural frequencies in said filtering means to modify a velocity waveform of the movement of conveying said flasks such that the modified velocity waveform does not include the first and second natural frequencies; driving said electric pusher-cylinder and said electric cushion-cylinder such that the velocity waveform of the movement of conveying said flasks is said modified velocity waveform.
2 . A system of suppressing sloshing in a casting line, wherein said casting line includes:
a conveying line in which an electric pusher-cylinder is located at one end of the conveying line for intermittently pushing out a plurality of flasks, wherein each contains a mold, one by one, and an electric cushion-cylinder is located at the other end of said conveying line and is opposed to said electric pusher-cylinder to receive and cushion a group of said pushed flasks such that said conveying line that conveys said plurality of flasks is arranged linearly between said electric pusher-cylinder and said electric cushion-cylinder; and an automatic pouring device that has a ladle for containing molten metal and that can be moved in synchronization with the flask on the conveying line, to pour the molten metal into the mold by tilting said ladle; wherein said system that controls said casting line such that the sloshing that occurs in the molten metal in said ladle and said mold is suppressed when said ladle and said mold move by a distance corresponding to one flask; said system comprising: a first weight-calculation means for calculating the weight of the molten metal in said ladle; a second weight-calculation means for calculating a second natural frequency of the molten metal in said mold; a first natural frequency-calculation means for calculating a first natural frequency based on a predetermined relationship between the weight and the natural frequency for the molten metal in said ladle, and the calculated weight of the molten metal in said ladle by said first weight-calculation means; a second natural frequency-calculation means for calculating a second natural frequency based on a predetermined relationship between the weight and the natural frequency for the molten metal in said mold, and the calculated weight of the molten metal in said mold by said second weight-calculation means; filtering means for modifying a velocity waveform of the movement of conveying of said flasks on said conveying line such that the modified velocity waveform does not include the first and second natural frequencies calculated by said first and second natural frequency-calculation means; and instructing means for providing operating instructions to said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device, based on said modified velocity waveform.
3 . A method of suppressing sloshing in a casting line, wherein said casting line includes:
a conveying line in which an electric pusher-cylinder is located at one end of the conveying line for intermittently pushing out a plurality of flasks, wherein each flask contains a mold, one by one, and an electric cushion-cylinder is located at the other end of said conveying line and is opposed to said electric pusher-cylinder to receive and cushion a group of said pushed flasks such that said conveying line conveys said plurality of flasks and is arranged linearly between said electric pusher-cylinder and said electric cushion-cylinder; an automatic pouring device that has a ladle for containing molten metal and that can be moved in synchronization with the flask on the conveying line, to pour the molten metal into the mold by tilting said ladle; driving means for driving said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device along a conveyed direction of said flasks; controlling means for controlling said driving means; and instructing means for providing operating instructions for said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device to said driving means through said controlling means wherein; said method controls said casting line using a controller having filtering means, based on a feedforward control program such that the sloshing that occurs in the molten metal is suppressed when said ladle and said mold move by a distance corresponding to one flask, said method comprising: calculating a first natural frequency of the molten metal in said ladle based on a predetermined relationship between the weight and the natural frequency for the molten metal in said ladle, and the measured weight of the molten metal in said ladle, and calculating a second natural frequency of the molten metal in said mold based on a predetermined relationship between the weight and the natural frequency for the molten metal in said mold, and the measured weight of the molten metal in said mold; under the first natural frequency, the second natural frequency, and the parameters of said controlling means that are preliminarily calculated such that they do not exceed the capacities of said driving means and are stored, removing components that are located near the first and second frequencies from the operating instructions, in which the maximum value of at least one of a velocity of the movement, an acceleration of the movement, and a jerk of the movement of said ladle and said mold is restricted, by said filtering means using said stored parameters, wherein said components to be removed are decided based on a simulation using a model representing the characteristics of said casting line to repeatedly calculate said component by the following equation (1) or (2),
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while gradually varying filtering parameters ai(f), bj(f) that are parameterized by a resonance frequency f that are successively calculated from the molten metal in said ladle and said mold, wherein y (t-i) is time-series data that are output before i controlling cycles, x(t-j) is time-series data that are input before j controlling cycles, S is the Laplace operator, and equation (1) can be derived by applying a Z transformation to the transfer function of the filter that is expressed as equation (2); and
entering the operating instructions, in which said components that are located near the first and second frequencies have been removed, in said controlling means based on only said feedforward controlling program, to operate said driving means based on only said feedforward controlling program without using a feedback control program.
4 . A system for the suppression of sloshing in a casting line, wherein said casting line includes:
a conveying line in which an electric pusher-cylinder is located at one end of the conveying line for intermittently pushing out a plurality of flasks that each contain a mold, one by one, and an electric cushion-cylinder is located at the other end of said conveying line and is opposed to said electric pusher-cylinder to receive and cushion a group of said pushed flasks such that said conveying line conveys said plurality of flasks and is arranged linearly between said electric pusher-cylinder and said electric cushion-cylinder; an automatic pouring device that has a ladle for containing molten metal and that can be moved in synchronization with the flask on the conveying line, to pour the molten metal into the mold by tilting said ladle; driving means for driving said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device along a conveyed direction of said flasks; and controlling means for controlling said driving means; wherein said system controls said casting line to suppress the sloshing that occurs in the molten metal in said ladle and the mold when said ladle and said mold move by a distance corresponding to one flask, said system comprising: a first weight-calculation means for calculating the weight of the molten metal in said ladle; a second weight-calculation means for calculating a second natural frequency of the molten metal in said mold; a first natural frequency-calculation means for calculating a first natural frequency based on a predetermined relationship between the weight and the natural frequency for the molten metal in said ladle, and the calculated weight of the molten metal in said ladle by said first weight-calculation means; a second natural frequency-calculation means for calculating a second natural frequency based on a predetermined relationship between the weight and the natural frequency for the molten metal in said mold, and the calculated weight of the molten metal in said mold by said second weight-calculation means; instructing means for providing operating instructions based on a feedforward program for operations of said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device, to said driving means through said controlling means; parameter calculation means for preliminarily calculating the parameters of said controlling means such that the calculated parameters do not exceed the capacity of said driving means; storing means for receiving and storing the calculated parameters from said parameter calculation means; restriction means for restricting a maximum value of at least one of a velocity of the movement, an acceleration of the movement, and a jerk of the movement of said automatic pouring device and said mold; filtering means for receiving the first and second resonance frequencies from said first and second frequency-calculation means, and for removing components that are located near the first and second frequencies from the operating instructions, in which the maximum value is restricted by said restriction means, using the stored parameters from the stored means, wherein said components to be removed are decided based on a simulation using a model representing the characteristics of said casting line to repeatedly calculate said component, under said stored parameters, by the following equation (1) or (2),
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while gradually varying filtering parameters ai(f), bj(f) that are parameterized by a resonance frequency f that are successively calculated from the molten metal in said ladle and said mold, wherein y (t-i) is time-series data that are output before i controlling cycles, x(t-j) is time-series data that are input before j controlling cycles, S is the Laplace operator, and equation (1) can be derived by applying a 2 transformation to the transfer function of the filter that is expressed as equation (2); and
wherein said instructing means provides said controlling means with operating instructions in which said components that are located near the first and second frequencies have been removed such that said controlling means carries out the controls based on only said feedforward controlling program without using a feedback control program.
5 . A computer readable media storing a computer program for the suppression of sloshing in a casting line, wherein said casting line includes:
a conveying line in which an electric pusher-cylinder is located at one end of the conveying line for intermittently pushing out a plurality of flasks that each contain a mold, one by one, and an electric cushion-cylinder is located at the other end of said conveying line and is opposed to said electric pusher-cylinder to receive and cushion a group of said pushed flasks such that said conveying line conveys said plurality of flasks and is arranged linearly between said electric pusher-cylinder and said electric cushion-cylinder; and an automatic pouring device that has a ladle for containing molten metal and that can be moved in synchronization with the flask on the conveying line, to pour the molten metal into the mold by tilting said ladle; wherein said computer program causes a computer having filter means to control said electric pusher-cylinder and said electric cushion-cylinder such that the sloshing that occurs in the molten metal is suppressed when said ladle and said mold move by a distance corresponding to one flask, said computer program comprising the steps to be executed by said computer of: calculating a first natural frequency of the molten metal in said ladle based on a predetermined relationship between the weight and the natural frequency for the molten metal in said ladle, and the measured weight of the molten metal in said ladle, and calculating a second natural frequency of the molten metal in said mold based on a predetermined relationship between the weight and the natural frequency for the molten metal in said mold, and the measured weight of the molten metal in said mold; entering the first and second natural frequencies in said filtering means to modify a velocity waveform of the movement of conveying of said flasks such that the modified velocity waveform does not include the first and second natural frequencies; and driving said electric pusher-cylinder and said electric cushion-cylinder such that the velocity waveform of the movement of conveying of said flasks is said modified velocity waveform.
6 . A computer readable media storing a computer program for the suppression of sloshing in a casting line, wherein said casting line includes:
a conveying line in which an electric pusher-cylinder is located at one end of the conveying line for intermittently pushing out a plurality of flasks that each contain a mold, one by one, and an electric cushion-cylinder is located at the other end of said conveying line and is opposed to said electric pusher-cylinder to receive and cushion a group of said pushed flasks such that said conveying line that conveys said plurality of flasks is arranged linearly between said electric pusher-cylinder and said electric cushion-cylinder; an automatic pouring device that has a ladle for containing molten metal and that can be moved in synchronization with the flask on the conveying line, to pour the molten metal into the mold by tilting said ladle; driving means for driving said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device along a conveyed direction of said flasks; controlling means for controlling said driving means; and instructing means for providing operating instructions for said electric pusher-cylinder, said electric cushion-cylinder, and said automatic pouring device to said driving means through said controlling means; wherein said computer program causes a computer having filter means to control said electric pusher-cylinder and said electric cushion-cylinder such that the sloshing that occurs in the molten metal is suppressed when said ladle and said mold move by a distance corresponding to one flask, said computer program comprising the steps to be executed by said computer of: calculating a first natural frequency of the molten metal in said ladle based on a predetermined relationship between the weight and the natural frequency for the molten metal in said ladle, and the measured weight of the molten metal in said ladle, and calculating a second natural frequency of the molten metal in said mold based on a predetermined relationship between the weight and the natural frequency for the molten metal in said mold, and the measured weight of the molten metal in said mold; under the first natural frequency, the second natural frequency, and parameters of said controlling means that are preliminarily calculated such that they do not exceed capacities of said driving means and are stored, removing components that are located near the first and second frequencies from the operating instructions, in which at least one of a velocity of the movement, an acceleration of the movement, and a jerk of the movement of said ladle and said mold, by said filtering means using said stored parameters, wherein said components to be removed are decided based on a simulation using a model representing characteristics of said casting line to repeatedly calculate said components by the following equation (1) or (2),
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=
b
0
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+
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1
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while gradually varying filtering parameters ai(f), bj(f) that are parameterized by a resonance frequency f that are successively calculated from the molten metal in said ladle and said mold, wherein y (t-i) is time-series data that are output before i controlling cycles, x(t-j) is time-series data that are input before j controlling cycles, S is the Laplace operator, and equation (1) can be derived by applying a Z transformation to the transfer function of the filter that is expressed as equation (2); and
entering the operating instructions, in which said components located near the first and second frequencies have been removed, in said controlling means based on only said feedforward controlling program, to operate said driving means based on only said feedforward controlling program without using a feedback control program.Cited by (0)
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