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The productivity of numerical control (NC) machining is highly limited by the occurrence of chatter vibration. Chatter stability analyses are widely studied to predict chatter vibration. However, these analyses often fail to provide reliable prediction results because the parameters in the vibration model are sensitive to identification errors, mechanical deterioration and thermal changes. On the...
We present a novel dynamic optical path control algorithm for Grouped Routing that can greatly enhance fiber frequency utilization. Careful grooming is shown to effectively mitigate the routing penalty even with dynamic optical path control.
We proposed a novel elastic optical network architecture employing Grouped Routing that enhances frequency utilization. With a developed network design algorithm, necessary fiber number was further reduced +20% compared with conventional elastic optical path network.
In controlling ball-screw driven stages of machine tools, industrial robots, and welfare robots, they are modelled as two-inertia systems to consider their transmission characteristics such as low rigidity and nonlinearity. To obtain precise position at the load side, the number of devices with load-side encoders is increasing. The precise joint torque control method and the load-side torque control...
In high-precision positioning of feed drive systems, mechanical resonances are one of the main limiting factor for fast and precise motion. Vibration suppression tracking controllers are employed to improve positioning performance, although precise plant models are generally required. Hence, in systems with time-varying modes, the increasing modeling errors often result in the loss of the needed performance...
Chatter vibration is well known as an undesirable phenomenon, so various methods for chatter suppression have been proposed. Spindle speed variation as a triangular trajectory in the cutting process is one of the methods for chatter suppression. However, this method cannot suppress chatter vibration completely. Moreover, the triangular spindle speed variation requires large torque and a good response...
We develop a novel network control algorithm that enhances fiber spectral efficiency and scalability of OXCs. Numerical experiments demonstrate that the spectral efficiency is improved more than 20% and necessity WSSs is reduced by 80%.
We investigate the performances of Grouped Routing which greatly mitigates the filter passband narrowing effect. Numerical experiments demonstrate that the optimal modulation format and channel spacing, considering the impairment by filtering effect and fiber transmission, can reduce the necessary number of fibers by up to 21.9%.
We propose a novel control algorithm for Grouped Routing networks that utilize a metric for residual capacity estimation. Numerical experiments under growing traffic scenarios confirm that it can maximize the fiber frequency utilization.
We demonstrate that fiber capacity can be substantially increased by utilizing grouped optical path routing in a traffic growth scenario. The developed algorithm is shown to substantially mitigate filter pass band narrowing at ROADMs.
This paper proposes a spindle motor control method for self-excited chatter vibration suppression in numerical control (NC) machine tools. In conventional NC machine tools, spindle speed is set to constant value during machining, and the spindle speed is determined according to analysis or operator's experience. The proposed method reduces self-excited chatter vibration by varying spindle speed with...
Optical path grouped routing not only simplifies the node's architecture, but also mitigates the signal degradation due to optical filtering at each node. It can improve frequency utilization of fibers or mitigate WSS requirements.
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