Distributed control system architecture and method for a material transport system
First Claim
1. A distributed control system for a material transport system, comprising:
- a high-level controller;
at least one mid-level controller coupled to the high level controller; and
a plurality of low-level controllers coupled to the at least one mid-level controller;
in response to commands from a respective mid-level controller, each of the low-level controllers being configured to control directly a respective group of one or more electromechanical devices, the group being selected from a plurality of electromechanical devices composing the material transport system;
the respective mid-level controller being configured to formulate the commands in accordance with local goals formulated for the respective mid-level controller by the top-level controller;
the top-level controller being configured to formulate the local goals in accordance with a global goal for a transfer operation pending in the material transport system.
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Abstract
An automated transport system for use in a material handling system. The automated transport system employs a distributed control system including a top level controller (transport controller), a plurality of second-level controllers (control logic computers) and a plurality of third-level controllers (intelligent drivers). The transport controller (TC) receives material commands from a conventional material control system (MCS). The TC breaks the command into sub-commands directing selected control logic computers (CLCs) to acquire, move to a destination or otherwise interact with a particular container designated by the MCS command. The transport controller selects the CLCs based on the transport system topology, the content of the MCS command and knowledge of which regions of the transport system are controlled by respective CLCs. Each CLC implements the sub-commands by issuing to the intelligent drivers low level control commands to accelerate, elevate, rotate, load or unload the container. Each intelligent driver directly controls one of the electromechanical devices that compose the transport system hardware in accordance with these low level commands. The electromechanical devices can include rail sections (zones), directors, elevators, load port transfer devices and tag readers.
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Citations
29 Claims
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1. A distributed control system for a material transport system, comprising:
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a high-level controller;
at least one mid-level controller coupled to the high level controller; and
a plurality of low-level controllers coupled to the at least one mid-level controller;
in response to commands from a respective mid-level controller, each of the low-level controllers being configured to control directly a respective group of one or more electromechanical devices, the group being selected from a plurality of electromechanical devices composing the material transport system;
the respective mid-level controller being configured to formulate the commands in accordance with local goals formulated for the respective mid-level controller by the top-level controller;
the top-level controller being configured to formulate the local goals in accordance with a global goal for a transfer operation pending in the material transport system. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of configuring a distributed control system for a material transport system, comprising:
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defining a set of neighborhoods including electromechanical devices composing the material transport system, wherein each of the neighborhoods includes the electromechanical devices that are likely to interact based on topology of the material transport system;
providing a low-level controller for the electromechanical devices, the low-level controllers being configured to translate generalized control commands to low-level control commands for the respective electromechanical device and to report status of the respective electromechanical device;
providing a higher-level controller that controls all low-level controllers associated with at least one of the neighborhoods via the generalized control commands;
compartmentalizing processing within the higher-level controller so that information regarding no more than the electromechanical devices composing the associated neighborhood is used to formulate the generalized control commands for low-level controllers associated with that one neighborhood.
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8. A computer program product for use in a material transport system including a plurality of electromechanical devices and a control computer, wherein the computer program product includes a computer memory coupled to the control computer and a computer mechanism defined therein, the computer mechanism comprising:
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control threads that configure the control computer to control and monitor operations of the electromechanical devices;
one of the control threads associated with a particular electromechanical device communicating with others of the control threads associated with a group of electromechanical devices that interact with the particular electromechanical device so that the one control thread and the others cooperatively accomplish a goal involving movement of material using the particular electromechanical device and the group of electromechanical devices. - View Dependent Claims (9, 10, 11)
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12. A distributed method for controlling movement of material to be transported in a material transport system, comprising:
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defining a neighborhood including a contiguous subset of electromechanical devices composing the material transport system, the electromechanical devices including track zones configured to control the movement of the material and to report zone status information;
providing low-level controllers to control the subset of electromechanical devices and to receive status information from the electromechanical devices, the low-level controllers including zone controllers, each of which is configured to control and receive zone status information from a respective track zone and to receive messages from zone threads in the neighborhood; and
configuring each of the zone threads to;
determine using the zone status information when the material is entering a respective track zone;
determine from stored information updated by a neighboring, upstream zone thread an entry speed at which the material is entering the respective track zone;
issue a motor control command to the respective track zone to establish the speed of the material in accordance with a speed profile message forwarded by the upstream zone thread and the entry speed;
determine from the stored information updated by neighboring, downstream zones the speed at which the material should enter a neighboring downstream zone;
determine from a potential entry speed and location of a destination of the material a speed profile of the material in one or more neighboring, downstream zones, send the speed profile message to the one or more neighboring, downstream zones causing the speed profile to be executed. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A distributed method for routing material from a source to a destination in a material transport system including track zones and directors connecting the track zones, comprising:
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launching the material from the source;
when the material enters a track neighborhood that includes a director through which the material must pass to proceed to the destination, notifying the director of the approach of the material;
the director, in response to the notifying, selecting an optimal route for the material based on the destination and stored routing information indicating for each material transport system destination a director exit angle and a metric characterizing quality of a path to the destination originating from the director exit angle; and
the director subsequently decelerating the material, rotating to the director exit angle associated with the optimal route and relaunching the material along the optimal route. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification