On Motion of Robot End-Effector Using the Curvature Theory of Timelike Ruled Surfaces with Timelike Rulings

The trajectory of a robot end-effector is described by a ruled surface and a spin angle about the ruling of the ruled surface. In this way, the differential properties of motion of the end-effector are obtained from the well-known curvature theory of a ruled surface. The curvature theory of a ruled surface generated by a line fixed in the end-effector referred to as the tool line is used for more accurate motion of a robot end-effector. In the present paper, we first defined tool trihedron in which tool line is contained for timelike ruled surface with timelike ruling, and transition relations among surface trihedron: tool trihedron, generator trihedron, natural trihedron, and Darboux vectors for each trihedron, were found. Then differential properties of robot end-effector's motion were obtained by using the curvature theory of timelike ruled surfaces with timelike ruling

On Motion of Robot End-Effector Using the Curvature Theory of Timelike Ruled Surfaces with Timelike Rulings

The trajectory of a robot end-effector is described by a ruled surface and a spin angle about the ruling of the ruled surface. In this way, the differential properties of motion of the end-effector are obtained from the well-known curvature theory of a ruled surface. The curvature theory of a ruled surface generated by a line fixed in the end-effector referred to as the tool line is used for more accurate motion of a robot end-effector. In the present paper, we first defined tool trihedron in which tool line is contained for timelike ruled surface with timelike ruling, and transition relations among surface trihedron: tool trihedron, generator trihedron, natural trihedron, and Darboux vectors for each trihedron, were found. Then differential properties of robot end-effector's motion were obtained by using the curvature theory of timelike ruled surfaces with timelike ruling

Electrochemical mechanical polishing technology: recent developments and future research and industrial needs

Electrochemical mechanical (ECM) polishing processes are widely used in various industries such as die and mould manufacturing, turbine blades, and components with complex surfaces. They are used to improve the surface quality and get glossy surfaces with enhanced mechanical properties. In this paper, the authors first look into the fundamental principles of the ECM polishing technology. Then the main parameters that affect the ECM polishing process such as applied voltage, electrolyte concentration, rotational speed and polishing pressure are discussed, and the related research issues are raised. Studying these parameters will enhance the performance, increase the efficiency of ECM polishing technology and provide a useful reference for further developments. Up to date, automatic ECM polishing is limited for planarization process and surfaces with simple geometry such as hole-wall and rotary surfaces. In addition, in some of ECM finishing technologies, the limited available working space usually forces the manufacture to machine one part in multiple stages. Because robots have some advantages over conventional machines such as flexibility, low price and mechanical reconfigurability, they are an effective and economical solution for ECM polishing of geometrically complex workpieces. In order to advance the ECM technology for the next competitive stage where a promising quantitative and qualitative processing is required, the authors proposed that the future researches on ECM polishing should also include ECM polishing using robots. In addition, the authors propose several configurations and setups of robotic ECM polishing systems. The research topics in this area should include designing of new ECM polishing tools, investigating the synergistic effects of additional sources of energies such as magnetic field and ultrasonic vibrations besides the normal effect of ECM tools and developing models and control methods of the processes