Distributed control system
First Claim
1. A distributed control system comprising:
- a plurality of control units connected by a network and executing a plurality of tasks in a distributed manner, wherein each of the plurality of control units having a task management list for tasks requested to run as the tasks to be executed by itself, wherein each of the tasks includes information of a deadline or task run cycle period as time required until task completion, and wherein each of the plurality of control units determines whether all tasks listed in said task management list can be completed in compliance with said deadline or task cycle period, if not as determined, selects a task that can be executed by another control unit in compliance with said deadline or task cycle period from among the tasks listed in said task management list, and requests another control unit to execute the task.
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Abstract
In a distributed control system where a plurality of control units are connected via a network, the invention allows for efficient operation of each control unit, while ensuring real-time processing. To provide a distributed control system in which ensured real-time processing and enhanced fault tolerance are achieved, information of a deadline or task run cycle period as time required until task completion is given for each task and a control unit on which a task will be executed is selected according to the deadline or task cycle period. A first control circuit and related sensors and actuators are connected by a dedicated path on which fast response time is easy to ensure and another control circuit and related sensors and actuators are connected via a network. When the first control circuit operates normally with sufficient throughput, the first control circuit is used for control; in case the first control circuit fails or if its throughput is insufficient, another control circuit is used.
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Citations
19 Claims
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1. A distributed control system comprising:
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a plurality of control units connected by a network and executing a plurality of tasks in a distributed manner, wherein each of the plurality of control units having a task management list for tasks requested to run as the tasks to be executed by itself, wherein each of the tasks includes information of a deadline or task run cycle period as time required until task completion, and wherein each of the plurality of control units determines whether all tasks listed in said task management list can be completed in compliance with said deadline or task cycle period, if not as determined, selects a task that can be executed by another control unit in compliance with said deadline or task cycle period from among the tasks listed in said task management list, and requests another control unit to execute the task. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A distributed control system comprising:
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a first control circuit having a first sensor;
second and third control circuits which process first information from said first sensor;
a first dedicated path connecting the first and second control circuits; and
a second path connecting the first and third control circuits, wherein said first information may be transferred to the second control circuit via the first path or transferred to the third control circuit via the second path. - View Dependent Claims (13, 14, 15, 16)
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17. A distributed control system comprising
a plurality of first control units, each including a sensor, a first control circuit connected to said sensor, a second control circuit which processes information from said sensor, an actuator which responds to a signal from said first control circuit, and a dedicated path connecting said first control circuit and said second control circuit, and a network linking said plurality of control units, wherein said first control circuit and said second control circuit of each of the plurality of first control units are connected to said network.
Specification