Patent ID: 7275623

Claim:
A method for controlling an elevator group, in which method the calls are allocated by fulfilling a target value of a desired service time and minimizing the energy consumption, characterized in that the method comprises the steps of: generating possible elevator route alternatives on the basis of the status of the elevators at the relevant moment and the existing calls; a cost function with the service time for the route alternative and the energy consumption required by the route alternative as variables is defined; assigning a target value to a given service time of the elevator group; predicting the said service time on a continuous basis in a model of the elevator system; calculating the difference between the said target value and the said service time; calculating a weighting coefficient for normalized energy consumption and a weighting coefficient for a normalized sum of service times; summing the normalized sum of service times for the route alternative considered in the cost function to the normalized energy consumption caused by the said route alternative with the calculated weighting coefficients; a set of route alternative solutions giving the lowest energy consumption is defined; from the set of solutions thus obtained, the solution that fulfills the desired service time is selected; and the calls are allocated to the elevators by minimizing the said cost function so that the given target value of the service time is fulfilled.