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Hitachi

Elevators, Escalators

A stress free service is achieved by complete elimination of the most critical issue, long waiting times during congestion periods.

Hitachi has evolved its elevator operation control to reduce waiting times, particularly long wait times, which comprises the heart of group control performance.
The future reference-trajectory control is a group control system aiming to minimize the long waiting period by operating elevator cars at equal time intervals while forecasting future trajectory.

What is Future Reference-Trajectory Control?*

Generally speaking, a group of elevator cars must be operated at equal time intervals to minimize passenger waiting times, but in heavy traffic conditions, cars are frequently operated in a bunch, or all cars would end up clustering around the same level on their way and moving in the same direction in unison. In the conventional method, the most available cars at that moment are allocated to hall calls to eliminate local bunching, but when heavy traffic conditions are prolonged, this state cannot be completely eliminated, resulting in long waiting times.
In contrast, with future reference-trajectory control, elevator cars are controlled by taking into account their forecasted trajectories, allowing shorter passenger waiting times and reducing the probability of a long wait.

Evolution of equal elevator allocation control

Future reference-trajectory control
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[Future reference-trajectory control <Patent application numbers in various countries>]
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Japan: Patent Application No. 2005-82906
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U.S.: US 11/210903
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Europe: EP 05017313.7
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China: CN 200510108790.6
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Singapore: SG 200505409-3