A Speed Smoothing Algorithm in Micro Segment High-Speed Machining

A forecasting speed smoothing algorithm based on inflexion velocity has been presented in this paper. According to the geometry characters of the machining trajectory, the inflexions in CNC machining tool path can be confirmed by using the designed algorithm. The line segment between each inflexion can be treated as a continuous path that can be tracked under the continuous feed rate. Moreover the maximal permitted link-up speed can be calculated through dynamic restriction equations and the real-time modification of sinusoidal acceleration can be realized by using the speed iteration algorithm. By simulation analysis, it can be revealed that both the flexibility and efficiency of the CNC machining has been improved and the impact to the machine tool has been greatly reduced.

Dynamics of a Radial Electrorheological Clutch

Time dependent solutions to the equations of motion for flow in an enclosed radial electro-rheological clutch are developed and discussed in relation to the speed of operation. The method follows a procedure previously developed for cylindrical clutch geometry but in this case analytical solutions are obtained. The fluid is treated as a homogeneous continuum obeying the Bingham plastic constitutive equation incorporating a yield stress and viscous component. The results show that the acceleration expected from a consideration of yield stress and inertia is not always achieved. The viscous component places fluid dynamic restriction on the maximum acceleration of the output rotor. However, this limit is only approached if the output load inertia is very low. The results have a bearing on the choice of fluid for high speed operation.