Chatter leaves a rough machined surface, accelerates wear of the cutter and creates unacceptably loud noise levels. A conventional approach to suppress chatter is to slow the material removal rate. Such an action is usually successful to avoid chatter, but causes increased production time and cost. Therefore, it is desirable to maintain a reasonably fast rate of production and employ a chatter control measure. In this research, a semi-active parameter control technique is investigated numerically during a robotic turning process. Investigations have been performed on a two-link robotic arm model. The control of chatter has been achieved by varying the joint stiffness in a synchronized mode with the spindle speed. Stability lobe diagrams have been compared for controlled and uncontrolled cases. Simulation results showed that significant improvements can be achieved by varying the joint stiffness of robotic structures. The proposed method is stable, effective and requires no additional hardware to implement at the actuated joints of robots. © 2012 Elsevier Ltd.