One of the most critical issues in wireless sensor networks is the limited energy availability of the network nodes. This paper is investigating the advantages of using controlled sink mobility in clustered wireless sensor networks (WSNs) which increases network lifetime. In a clustered sensor network all Cluster Heads (CHs) have to transmit their buffered data to the sink during a specified interval, called data reporting time (tdr). In this paper, we propose a scheme that prescribes the sink path for collecting all CHs data in tdr time span while maximizing network life time using the mathematical model MILP (Mixed Integer Linear Programming). The proposed scheme is compared with other related schemes by means of various simulation scenarios. Simulation results show that the proposed scheme significantly outperforms other schemes.