Relative system response elevator dispatcher system using artificial intelligence to vary bonuses and penalties

• US 5,024,295 A
• Filed: 03/03/1989
• Issued: 06/18/1991
• Est. Priority Date: 06/21/1988
• Status: Expired due to Fees

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Thangavelu, Kandasamy
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Duncanson, Jr., W. E.
• Application Number:
  US07/318,307
• Time in Patent Office: 837 Days
• Field of Search: 187/124, 187/125, 187/127
• US Class Current: 187/382
• CPC Class Codes: B66B 1/2458 For elevator systems with multiple shafts and a single car per shaft
• CPC Class Codes: B66B 2201/102 Up or down call input
• CPC Class Codes: B66B 2201/211 Waiting time, i.e. response time
• CPC Class Codes: B66B 2201/213 where the number of stops is limited
• CPC Class Codes: B66B 2201/214 Total time, i.e. arrival time
• CPC Class Codes: B66B 2201/215 Transportation capacity
• CPC Class Codes: B66B 2201/222 Taking into account the number of passengers present in the elevator car to be allocated
• CPC Class Codes: B66B 2201/233 Periodic re-allocation of call inputs
• CPC Class Codes: B66B 2201/235 Taking into account predicted future events, e.g. predicted future call inputs
• CPC Class Codes: B66B 2201/243 Distribution of elevator cars, e.g. based on expected future need
• CPC Class Codes: B66B 2201/402 by historical, statistical or predicted traffic data, e.g. by learning
• CPC Class Codes: B66B 2201/403 by real-time traffic data

Abstract

An elevator system employing a micro-processor-based group controller (FIG. 2) communicating with the cars (3, 4) to assign cars to hall calls based on a Relative System Response (RSR) approach. However, rather than using unvarying bonuses and penalties, the assigned bonuses and penalties are varied using "artificial intellience" techniques based on combined historic and real time traffic predictions to predict the number of people behind a hall call, and, calculating and using the average boarding and de-boarding rates at "en route" stops, and the expected car load at the hall call floor. Prediction of the number of people waiting behind hall calls for a few minute intervals are made using traffic levels measured during the past few time intervals on that day as real time predictors, using a linear exponential smoothing model, and traffic levels measured during similar time intervals on previous similar days as historic traffic predictors, using a single exponential smoothing model. The remaining capacity in the car at the hall call floor is matched to the waiting queue using a hall call mismatch penalty. The car stop and hall stop penalties are varied based on the number of people behind the hall call and the variable dwell times at "en route" stops. The stopping of a heavily loaded car to pick up a few people is penalized using a car load penalty. These enhancements to RSR result in equitable distribution of car stops and car loads, thus improving handling capacity and reducing waiting and service times.

Claims

1. A method of controlling the dispatching of elevator cars based on a system of bonuses and penalties, said penalties including a car load penalty for penalizing the stopping of a relatively loaded elevator car at a predetermined floor registering a hall call, said method comprising the steps of:

determining the load of the car when the car reaches the predetermined floor;

comparing said determined load to a predetermined car load limit; and

determining said car load penalty based on said comparison.

2. The method of claim 1, wherein said car load penalty is substantially equal to zero if the car has a coincident car call stop at the predetermined floor.

3. The method of claim 1, said method further comprising the steps of:

obtaining historical information of passenger arrival rates at the predetermined floor;

determining, based on said historical information, a passenger arrival rate at the predetermined floor;

predicting, based on said predetermined passenger arrival rate, the number of people waiting behind the hall call at the predetermined floor; and

determining said car load penalty based on said comparison and said predicted number of people.

4. The method of claim 3, wherein said car load penalty is substantially equal to zero if the car has a coincident car call stop at the predetermined floor.

5. A method of controlling the dispatching of elevator cars based on a system of bonuses and penalties, said penalties including a car load penalty for penalizing the stopping of a relatively loaded elevator car at a predetermined floor registering a hall call, said method comprising the steps of:

determining the load of the car when the car reaches the predetermined floor, C_ld ;

comparing said determined load, C_ld, to a predetermined car load limit, C_ldl ;

obtaining historical information of passenger arrival rates at the predetermined floor;

determining, based on said historical information, a passenger arrival rate at the predetermined floor;

predicting, based on said determined passenger arrival rate, the number of people waiting behind the hall call at the predetermined floor, N_phc ; and

determining said car load penalty based on said comparison and said predicted number of people based on the following equation;

space="preserve" listing-type="equation">a(C.sub.ld -C.sub.ldl)-b(N.sub.phc)

wherein "a" and "b" represent predetermined constants.

6. The method of claim 5, wherein "a" is in the range of about 0.3 to about 3.0.

7. The method of claim 5, wherein "b" is in the range of about 0.5 to about 1.5.

8. The method of claim 5, wherein said car load penalty is substantially equal to zero if the car has a coincident car call stop at the predetermined floor.

9. The method of claim 5, wherein said car load penalty is substantially equal to zero if said determined load, C_ld, is less than said predetermined car load limit, C_ldl.

10. A method of controlling the dispatching of elevator cars based on a system of bonuses and penalties, said penalties including a hall call mismatch penalty for penalizing the stopping of an elevator car based on a comparison of the elevator'"'"'s spare capacity with the number of people expected at a floor registering a hall call, said method comprising the steps of:

predicting car load at the floor registering the hall call should the car stop to pick-up and/or discharge passengers at all its currently scheduled stops;

predicting the number of people behind the hall call;

comparing said predicted number of people to a predetermined threshold;

determining the value of said hall call mismatch penalty based on said comparison.

11. The method of claim 10, wherein the step of determining the value of said hall call mismatch penalty based on said comparison, if said predicted number of people is less than said predetermined threshold, comprises the steps of:

assigning a relatively small number to said hall call mismatch penalty if said predicted car load is less than a predetermined car load limit;

or

assigning a relatively large number to said hall call mismatch penalty if said predicted car load is greater than or equal to a predetermined car load limit.

12. The method of claim 11, wherein said predetermined car load limit is about 80% of the maximum car load limit.

13. The method of claim 10, wherein the step of determining the value of said hall call mismatch penalty based on said comparison, if said predicted number of people is greater than or equal to said predetermined threshold, comprises the steps of:

comparing said predicted number of people to a first predetermined value; and

determining the value of said hall call mismatch penalty based on said comparison.

14. The method of claim 13, wherein the step of comparing said predicted number of people to a first predetermined value, if said predicted number of people is less than or equal to said first predetermined value, comprises the steps of:

predicting spare capacity in the car, based on said predicted car load; and

assigning a relatively large number to said hall call mismatch penalty if said predicted spare capacity is less than said predicted number of people;

or

assigning a relatively small number to said hall call mismatch penalty if said predicted spare capacity is greater than or equal to said predicted number of people.

15. The method of claim 13, wherein the step of comparing said predicted number of people to a first predetermined value, if said predicted number of people is greater than said first predetermined value, comprises the steps of:

predicting spare capacity in the car, based on said predicted car load;

comparing said predicted spare capacity to a second predetermined value; and

determining the value of said hall call mismatch penalty based on said comparison.

16. The method of claim 15, wherein the step of determining the value of said hall call mismatch penalty based on said comparison, if said spare capacity is less than said second predetermined value, comprises the step of:

assigning a relatively large number to said hall call mismatch penalty.

17. The method of claim 15, wherein the step of determining the value of said hall call mismatch penalty based on said comparison, if said spare capacity is greater than or equal to said second predetermined value, comprises the step of:

assigning a relatively small number to said hall call mismatch penalty.

18. The method of claim 17, said method further comprising the step of:

generating a car request signal if said spare capacity is less than said predicted number of people.

19. The method of claim 18, said method further comprising the step of:

cancelling said generated car request signal if the car is not fully loaded after the car answers the hall call.

20. The method of claim 10, wherein the step of predicting car load comprises the steps of:

determining the floors where the car is scheduled to stop en route to said floor registering a hall call;

obtaining historical information of passenger boarding rates at the en route floors scheduled in response to a hall call;

determining, based on said historical boarding information, a passenger boarding rate at each of the en route floors scheduled in response to a hall call;

predicting, based on said predetermined passenger boarding rate, the number of people which will board the car at each of the en route floors scheduled in response to a hall call;

obtaining historical information of passenger deboarding rates at the en route floors scheduled in response to a car call;

determining, based on said historical deboarding information, a passenger deboarding rate at each of the en route floors scheduled in response to a car call;

predicting, based on said determined passenger deboarding rate, the number of people which will deboard the car at each of the en route floors scheduled in response to a car call;

determining the current car load; and

predicting car load should the car stop at the floor, based on said current car load, said predicted number of boarding people and said predicted number of deboarding people.