On a manipulator for xylophone-playing

Abstract

A xylophone-playing manipulator with control of two mallets is presented based on requires of playing xylophone. It consists of left mallet-driving device, right mallet-driving device and control system. Every mallet-driving device consists of a mallet-moving unit and a mallet-beating unit. By means of four servo motors being controlled respectively and encoders being used to detect positions of servo motors, the manipulator fulfills control movements of two mallets. Mallet-moving unit uses single linear motion guideway and slide seat dragging by synchronistic belt. Some performance parameters are analyzed and some factors effect on motion accuracy of the manipulator discussed. The mallet lies at an angle of 75 degrees with the linear guideway on the horizontal plane, and at an angle of 28 degrees with the linear guideway in the vertical plane. Control system and motion controller have also been introduced. It adopts host computer and slave computer control mode. Motion controller uses DSP as control chip and encoders for displacement detecting sensors. The results show that the xylophone-playing manipulator may preferably imitate two hands to play xylophone. It can play some music under the control of music programs in host computer. Synchronistic belt transmission and servo control system for position and velocity ensure accurate movement positioning. The linear motion guideway with ball bearing ensures high orientation precision and good anti-vibratility. DSP chip ensures the real time and rapid movements of a slide seat. The xylophone-playing manipulator has simple structure, agile motion and accurate playing positioning. Mallet-moving movement is quiet and smooth.