Title : 
Exact calculation of expected waiting times for group elevator control
         
        
            Author : 
Nikovski, Daniel ; Brand, Matthew
         
        
            Author_Institution : 
Mitsubishi Electr. Res. Labs., Cambridge, MA, USA
         
        
        
        
        
        
        
            Abstract : 
We present an efficient algorithm for exact calculation and minimization of expected waiting times of all passengers using a bank of elevators. The dynamics of the system are represented by a discrete-state Markov chain embedded in the continuous phase-space diagram of a moving elevator car. The chain is evaluated efficiently using dynamic programming to compute measures of future system performance such as expected waiting time, properly averaged over all possible future scenarios. A linear-time elevator group controller based on this method significantly outperforms benchmark algorithms and is completely within the computational capabilities of contemporary elevator bank controllers.
         
        
            Keywords : 
Markov processes; discrete systems; dynamic programming; lifts; optimal control; continuous phase-space diagram; discrete-state Markov chain; dynamic programming; group elevator control; optimal control; Automatic control; Circuits; Control system synthesis; Control systems; Controllability; Elevators; Linear matrix inequalities; Multidimensional systems; Observability; Time varying systems; Dynamic programming; Markov chains; group elevator scheduling; optimal control;
         
        
        
            Journal_Title : 
Automatic Control, IEEE Transactions on
         
        
        
        
        
            DOI : 
10.1109/TAC.2004.835583