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
Research on Roll Variable Speed Grinding Based on Adaptive Fuzzy Control
The traditional method of improving the machining precision is mainly on account of changes in the workpiece and the grinding wheel in grinding process, including, considered the weakest of the workpiece from the axial stiffness, using center frame to increase the stiffness of the workpiece, take error compensation, and analyze the mechanism of gear grinding and the suppression measures of variable speed grinding and grinding chatter. Based on the analysis of the relationship among gear grinding mechanism, variable speed grinding and grinding chatter suppression and grinding precision, the variable speed micro-feed grinding process strategy based on adaptive fuzzy control is put up, that is according to the roller material and structure to reasonably determine the characteristics of grinding wheel and the parameters of grinding process. And with full consideration of roll grinders, changes of roller system along the axial stiffness and the deformation control in the roll grinding process, a new strategy of variable speed grinding micro-feed adaptive control optimization based on adaptive fuzzy control is proposed, which for improving the accuracy of the grinding roll presents a new and effective solution.
Improved NCTF control method for a two mass point-to-point positioning system
In this study, a nominal characteristic trajectory following (NCTF) controller for point-to-point (PTP) positioning system is introduced for two mass rotary system and its performance is evaluated. Generally, the NCTF controller consists of a nominal characteristic trajectory (NCT) and a compensator. The objective of the NCTF controller is to make the object motion follow the NCT and end at its origin. The NCTF controller is designed based on a simple open-loop experiment of the object. The parameters and an exact model of the plant are not necessary for controller design. This paper presents a method to improve the existing NCTF controller for two mass rotary positioning system by adding a notch filter as a compensator to eliminate the vibration due to the mechanical resonance. The improved NCTF controller is evaluated and discussed based on results of simulation. The effect of the design parameters on the robustness of the NCTF controller to inertia and friction variations is evaluated and compared with conventional PID controller. It is shown that NCTF controller is better than conventional PID controller.