Production control system of autonomous and decentralized type

• US 7,241,044 B1
• Filed: 06/07/1995
• Issued: 07/10/2007
• Est. Priority Date: 11/14/1991
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Masuda, Shigeru, Kitamura, Koichi, Mohri, Shunji, Kamikubo, Tadamasa
• Primary Examiner(s): Elmore; Reba I.
• Assistant Examiner(s): Rao; Sheela S.
• Application Number:
  US08/483,885
• Time in Patent Office: 4,416 Days
• Field of Search: 364/468.22, 364/468.23, 364/468.2, 364/468.19, 364/468.01, 364/468.05, 364/468.06, 364/468.07, 364/478.07, 364/478.16, 364/478.17, 364/468.08, 364/468.18, 364/468.1, 395/670, 395/671, 395/673, 395/675
• US Class Current: 700/159
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/32256 Due dates, pieces must be ready, priority of dates, deadline
• CPC Class Codes: G05B 2219/32272 Decision of next visiting machine selection, where job is to go
• CPC Class Codes: G05B 2219/32277 Agv schedule integrated into cell schedule
• CPC Class Codes: G05B 2219/32283 Machine scheduling, several machines, several jobs
• CPC Class Codes: G05B 2219/32326 Local scheduler, each machine own scheduler, independent from defective machines
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

An autonomous and decentralized production control system comprising a plurality of production cells for performing the assembly and machining work. Each production cell proceeds with the production procedure by performing jobs in accordance with the works charged thereinto. A first embodiment comprises working cells each including a device for determining the working cell for executing an intended job. A second embodiment comprises a pallet for carrying an object of a job, and a device for determining the order of job priority in order to meet the product delivery time. Each working cell decides on the advisability and time of performing the job on the object, thereby autonomously implementing the production control.

Claims

1. A work driven production control system, comprising:

a plurality of pallets for carrying works;

a plurality of production equipment;

transport means for delivering a pallet to a given equipment;

an automatic warehouse for housing a given work to be delivered to a determined one of said pallets;

part supply means for delivering the given work from said automatic warehouse to the determined one of said pallets; and

job progress control means including job request right effectuation means for deciding to grant the job request right to a pallet carrying a work of top priority;

wherein each of said pallets includes equipment selection means, design information storage means for storing the design information of the work placed on the pallet, work information storage means for storing the job history and the present condition of said work, work priority determination means for calculating the order of priority of said work, and communication means for communicating with said production equipment, and

wherein said work priority determination means recalculates a priority by using at least a predicted maximum job time and a delivery time stored in said design information storage means after every job is correctly executed,

said equipment selection means includes means for receiving said job request right, determining whether or not a job is executable on the basis of said design information and said work information, and selecting equipment to perform the next job of said work on said pallet if the job is determined to be executable,

all of said production equipment includes;

communication means for exchanging information with said plurality of pallets and said job progress control means,

equipment information storage means,

job workability determining means for checking a job type from the pallet with the accuracy thereof stored in said equipment information storage means to determine the workability of a job,

equipment control data generation means for preparing NC data from the design information if the job workability determining means determines that the job is workable, and

job execution means for executing a job by applying the NC data obtained by said equipment control data generation means to actual equipment for executing the job and acting on said work.

2. A production control system of work driven type according to claim 1, wherein said pallets include both of said work priority determination means and job request right effectuation means, and individual ones of said pallets communicate with others of said pallets and a plurality of equipment thereby to determine the next job on the work in accordance with the priority of the work.

3. A production control system of work driven type according to claim 1, wherein the determination of whether or not a job is executable by said equipment selection means is performed in communication with said job workability determining means.

4. A production control system of work driven type according to claim 1, wherein said job request right effectuation means of said job progress control means collects priorities of works of said plurality of pallets and issues a request for permission to execute a job to one of said plurality of pallets carrying a top priority work, and

wherein said equipment selection means of said one of said plurality of pallets selects a job to be executed as work carried thereon based on the order of a plurality of jobs performed on said work stored as said design information in said design information storage means and work conditions stored as said work information in said work information storage means, determines workability of said job regarding a corresponding one of said plurality of production equipment corresponding to said selected job via said communication means, and determines one of said plurality of production equipment for performing a job to be executed based on a result of the determination.

5. A production control system of work driven type according to claim 4, wherein said equipment selection means selects a specific one of said plurality of equipment which has the least number of requests for execution of a job.

6. A production control system of work driven type according to claim 4, wherein said work priority determination means of said pallet, when recalculating a priority by using at least a predicted maximum job time and a delivery time stored in said design information storage means after every job is correctly executed, rearranges the recalculated priority of the jobs in descending order of priority.

7. A production control system of work driven type according to claim 4, wherein said equipment selection means inquires of all of said production equipment, via said communication means, whether respective ones of said production equipment are capable of executing the job.

8. A production control system of work driven type according to claim 4, wherein, when said equipment selection means of said one of said plurality of pallets is unable to find equipment capable of presently executing the job, said one of said plurality of pallets transfers the request for permission to execute the job to another one of said plurality of pallets.

9. A work driven production control system, comprising:

a plurality of pallets for carrying works, each of said pallets including job request right effectuation means for deciding to grant the job request right to a particular pallet carrying a work of top priority;

a plurality of production equipment;

transport means for delivering a pallet to a given one of said production equipment; and

an automatic warehouse for housing a given work to be delivered to a determined one of said pallets;

part supply means for delivering the given work from said automatic warehouse to the determined one of said pallets;

wherein each of said pallets further includes equipment selection means, design information storage means for storing the design information of the work placed on the pallet, work information storage means for storing the job history and the present condition of said work, work priority determination means for calculating the order of priority of said work, and communication means for communicating with said production equipment, and

wherein said work priority determination means recalculates a priority by using at least a predicted maximum job time and a delivery time stored in said design information storage means after every job is correctly executed,

said equipment selection means includes means for receiving said job request right, determining whether or not a job is executable based on said design information and said work information, and selecting equipment to perform the next job of said work on said pallet if the job is determined to be executable,

all of said production equipment includes;

communication means for exchanging information with said plurality of pallets,

equipment information storage means,

job workability determining means for checking a job type from the pallet with the accuracy thereof stored in said equipment information storage means to determine the workability of a job,

equipment control data generation means for preparing NC data from the design information if the job workability determining means determines that the job is workable, and

job execution means for executing a job by applying the NC data obtained by said equipment control data generation means to actual equipment for executing the job and acting on said work.

10. A production control system of work driven type according to claim 9, wherein said work priority determination means of said pallet, when recalculating a priority by using at least a predicted maximum job time and a delivery time stored in said design information storage means after every job is correctly executed, rearranges the recalculated priority of the jobs in descending order of priority.

11. A production control system of work driven type according to claim 9, wherein the determination of whether or not a job is executable by said equipment selection means is performed in communication with said job workability determining means.