Research On Contact Force Control Of Compliant Actuator For Mold Polishing

With the development of science and technology and manufacturing, mold is morewidely applied, especially in aerospace, automobile manufacturing and other high-tech fields.Since China joined to the World Trade Organization, various industry departments in ourcountry pay more and more attention to the mold manufacturing level with the increasinglyfierce market competition. The level of mold production technology has become an importantsymbol of a national manufacturing. So developing the mold of high-precision and high-techproducts are our development goals in future.Polishing is the final step in the mold manufacturing process, polishing directlydetermines the manufacturing accuracy, appearance and life of the mold. The structure of themold cavity surface is the complex free-form surface. When a common rigid tool such as agrinding wheel is used for polishing, it is not only difficult to adapt to the changes of thesurface, but also to control the surface roughness. If the polishing force is too large, there willbe a surface over-polishing; and if too small, desired accuracy and efficient can’t beguaranteed. In order to solve the above problems, a kind of electrical dual slide table which ismounted on the compliant end of the implementing agencies and the Cartesian coordinaterobot are designed to complete complex mold surface polishing and motion control. Themotion control of compliant mechanism is closely related to the polishing quality of moldsurface. So the research of motion control for mold polishing robot has very importanttheoretical significance and application value.In this paper, a kind of electrical dual slide table was designed on the basis of hybridrobot with compliant actuator. In order to improve polishing quality, combined force andposition control method was used to keep the contact force between polishing tool and moldsurface constant. First of all, polishing servo platform based on Cartesian coordinate robotwas introduced.Then the transfer function of the servo motor, sensor, and gear was inferred.Finally PID control, fuzzy control and adaptive fuzzy PID control were used and simulationdiagram of the three control methods by Matlab/Simulink were given, the adaptive fuzzyPID control was proved having a smaller overshoot, shorter settling time relative to the othertwo methods by comparative analysis, which provided a theoretical basis for the nextexperimental work.