4-Axis CNC Machine Tool for Relief Grinding Sphere Gear Hob
A new 4-axis machine tool, which is used for relief grind of sphere gears hob including spherical hob, elliptic hob and arc surface hob, is developed. The principle of relief machining of spherical hob is introduced first. Transmitting system, numerical system and some key techniques are then introduced. The machine tool can be reconfigured in machining of arc worms and spatial cams beside of machining of spherical hob. Four forms of the machine tool for machining different workpiece are also introduced. DOI: http://dx.doi.org/10.11591/telkomnika.v10i7.1557
Practical Control for Two-Mass Positioning Systems in Presence of Saturation
The precision positioning systems generally need a good controller to achieve a fast response, high accuracy and robustness. In addition, ease, simplicity of controller design structure and high motion control performance are very important for practical applications. For satisfying these requirements, nominal characteristic trajectory (NCT) with proportional integral (PI) and notch filter (NF) as a compensator has been proposed as a practical control method for two-mass rotary PTP positioning systems. However, the effect of the actuator saturation cannot be completely compensated due to integrator windup when the object parameter varies. This paper presents a method to further improve nominal characteristic trajectory following (NCTF) controller to overcome the problem of integrator windup by adopting PI anti-windup schemes. The improved NCTF controller is evaluated experimentally using two-mass rotary positioning systems. The effect of the design parameters on the robustness of the improved NCTF with anti-windup integrator controller is evaluated and compared with NCTF without antiwindup integrator and the equivalent PID controller. The results show that the improved NCTF controller is effective to compensate the effect of integrator windup.
Biodiversity, conservation, and sustainable development
This important book highlights the conflicts between economic growth and the conservation of nature in the context of sustainable development. It places particular emphasis on biological diversity and examines possible policies for resolving conflicts which arise from the contrasting goals of conserving the natural environment and economic growth.