Abstract:
A elevator system including a group controller for controlling the dispatching of elevator cars to the lobby. The group controller predicts lobby single source traffic for short periods. When the predicted traffic is below certain limit, cars are assigned to a lobby hall call on demand after hall call registration. When the predicted traffic is above certain limit, cars are assigned to the lobby hall call at intervals. Accordingly, car assignment is scheduled at those intervals. The traffic threshold at which the scheduled mode is activated and the traffic threshold at which it is deactivated is learned by the system. The schedule interval is varied based on predicted traffic and predicted round trip time of the cars. The number of cars assigned and sent to the lobby is varied based on predicted traffic. In order to avoid oscillations in selecting the service mode, proper delays are used to activate and deactivate the scheduled service.
Abstract:
A group controller for controlling elevator cars in a building having a plurality of floors includes a traffic and traffic rate estimator for providing fuzzy estimates of traffic and traffic rate; an open loop fuzzy logic controller for providing a control parameter in response to the fuzzy estimates of traffic and traffic rate; and an elevator dispatcher for controlling the operation of the elevator cars during single source traffic conditions in response to the control parameter.
Abstract:
A group controller for controlling elevator cars in a building having a plurality of floors includes a traffic and traffic rate estimator for providing fuzzy estimates of traffic and traffic rate; a closed loop fuzzy logic controller for providing a control parameter in response to the fuzzy estimates of traffic and traffic rate and in response to an elevator control system output variable, the closed loop fuzzy logic controller having membership functions for fuzzy sets of the control parameter; an adaptive controller for modifying the membership functions of the fuzzy sets of the control parameter in response to the elevator control system output variable; and an elevator dispatcher for controlling the operation of the elevator cars during single source traffic conditions in response to the control parameter.
Abstract:
The present invention is directed to determining an arrival time for each of the passengers boarding an elevator car. Where the elevator car stops at a floor in response to a hall call request, the arrival time of the passengers which boarded the elevator car is preferably determined based the time period between when the hall call was registered and when the elevator car door closed. Where the elevator car stops at a floor in response to a car call registered within the elevator, the arrival time of the passengers which boarded the elevator car is preferably determined based on the time period between when the elevator stopped at the floor and when the elevator car door closed. Alternatively, the time period between when the elevator car door opened and when the elevator car door closed can be used. In the preferred embodiment, the first passenger is assumed to have an arrival time corresponding to the beginning of the time period. If more than one passenger boarded the elevator, the passengers are assumed to have arrived in a distributed fashion over this time period.
Abstract:
A group controller for controlling elevator cars in a building having a plurality of floors includes a traffic and traffic rate estimator for providing fuzzy estimates of traffic and traffic rate; an open loop fuzzy logic controller for providing a control parameter in response to the fuzzy estimates of traffic and traffic rate, the open loop fuzzy logic controller having membership functions for fuzzy sets of the control parameter; an adaptive controller for modifying the membership functions of the fuzzy sets of the control parameter in response to an elevator control system output variable; and an elevator dispatcher for controlling the operation of the elevator cars during single source traffic conditions in response to the control parameter.
Abstract:
The present invention is directed to the grouping of contiguous floors in a building into sectors. According to the present invention, historical information regarding the number of passengers arriving at each floor is obtained and used to predict the number of passengers to be arriving at each of the floors. By summing the predicted traffic per floor and dividing by the number of sectors to be formed, average traffic per sector can be determined. In the preferred embodiment, sectors are formed, starting from the first floor above the lobby and continuing through to the top floor in the building, by selecting a set of contiguous floors for each sector such that the predicted traffic for each sector is less than a predetermined threshold. Specifically, if the predicted traffic for a selectable next contiguous floor, added to the predicted traffic for all contiguous floors already selected for the sector, is less than the predetermined threshold, the selectable floor is included in the sector. Otherwise, another sector is begun with the selectable floor as the bottom floor in the other sector. In the preferred embodiment, the predetermined threshold is based on the determined average traffic per sector. In another aspect of the present invention, the frequency of service of elevator cars to each sector is variable. The traffic volume for each formed sector is determined and compared with the determined average traffic per sector. The frequency of service of elevator cars to each sector is variable, based on this comparison. Thus, sectors having a larger traffic volume are serviced more often, relative to sectors having a smaller traffic volume.
Abstract:
The present invention is directed to an elevator dispatching system for controlling the assignment of elevator cars. More particularly, the present invention is directed to a method of determining the commencement and/or conclusion of UP-PEAK and DOWN-PEAK periods of operation. For example, for commencing UP-PEAK operation, a lobby boarding count is predicted, based on historical information of the number of passengers boarding the elevators at the lobby. The predicted lobby boarding count is compared with a predetermined threshold value. If the predicted lobby boarding count is greater than the predetermined threshold value, UP-PEAK is commenced. In the preferred embodiment, the predetermined threshold value is a predetermined percentage of the building's population. Additionally, the present invention is directed to a method of adjusting the threshold value based on actual passenger traffic. For example, once UP-PEAK is commenced, the load of the first few elevators leaving the lobby within a predetermined time interval is determined, and the threshold value is adjusted based on their determined load. If the determined load is greater than a certain percentage of the elevator car's capacity, indicative of starting UP-PEAK too late, the threshold value is decreased. Similarly, if the determined load is less than a certain percentage of the elevator car's capacity, indicative of starting UP-PEAK too soon, the threshold value is increased.
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.
Abstract:
A system for controlling elevator cars in a building having a plurality of floors includes a group controller for controlling operation of the elevator cars. The group controller predicts lobby single source traffic for determined periods. When the predicted traffic is below certain limit, cars are assigned to a lobby hall call on demand after hall call registration. When the predicted traffic is above certain limit, cars are assigned to the lobby hall call at intervals. Accordingly, car assignment is scheduled at those intervals. The schedule interval is varied based on predicted traffic and predicted round trip time of the cars. The cars are assigned to hall calls if they arrive within a schedule window. The schedule window comprises a lower and an upper tolerance that are selected around a scheduled time.
Abstract:
A system including a group controller for controlling the dispatching of elevator cars in a building. The group controller operates by using control parameters stored in its memory. The system records car loads of cars leaving the lobby and the time intervals between their departures and uses fuzzy logic to categorize the car loads and intervals into fuzzy sets. The system determines the lobby traffic and traffic rate using fuzzy relations among car loads, departure intervals, lobby traffic and traffic rate and the fuzzy logic rules. The group controller collects traffic data during operation. The system runs simulations off-line, after single source traffic periods, using the specified control parameter values. The system collects and analyzes performance data to identify significant deviations from acceptable performances. New sets of control parameters are selected using appropriate specified rules. The process of simulation and learning new values of control parameters are repeated until acceptable performance is achieved. The selected parameters are used in system operation. The group controller repeats this process of simulation and learning the parameters periodically.