7. CONCLUSIONS

Using an example the design of a control algorithm for traffic lights has been presented. As the state of the intersection must be known for an optimal decision, we assumed that there is a device (an observer) which reconstructs the intersection state by receiving sensor-readings of the input events. Given such a device and by using Dynamic Programming for optimisation it is straight forward to develop a control algorithm that minimises the overall waiting time (as shown) or maximises the throughput. Moreover, it has been shown that Branch-and-Bound techniques can be used to reduce the computational complexity.

The state space of the problem does not exhibit (explicitly) time, but ordered customers. The presented algorithm does not reduce this state space, but

the number of transitions is reduced, and

the number of states to be searched for is also reduced.

Problems only raised in the paper are subjects of further research:

design of an observer,

simulation of an intersection to test the controller and the observer,

robustness of controllers and observers with respect to unreliable sensor outputs.