A Control System Of The Solids Motion In Rotating Cylinder Based On Image Feedback

Rotary kilns are widely used in chemical and metallurgical industries, however, rotarykiln is high energy-consuming, the mass and heat transfer in a rotary kiln is to great extenddetermined by the motion of the granular solids passing through it. In present, the solidstransfer process studies are mainly focused on modeling theory, but no reports are devoted inautomatic monitoring and controlling of solids motion.According to the current situation of the development of the rotary kiln, laboratory userotary cylinder to simulate industrial rotary kiln. Features and key parameters of rolling andslumping motion are studied here. A real-time detection software is developed in this paper todetect the repose angle based on image processing techniques. The video of the solids motionis taken by a camera and transferred to a computer via an image-sampling box. With a VC++program, the image of the solids is captured and processed through segmentation, morphologyprocessing and edge detection. The repose angle is determined by linear fitting of the surfaceprofile of the solids bed. With the image processing system, the dynamic change of reposeangle with time can be measured and displayed automatically. Test on a250mm rotatingcylinder demonstrate the effectiveness of the proposed method.For practical users, rolling motion is preferred to slumping motion because it provides abetter mixing of particles and thus enhances the heat flux from the hot gas to the solids. Basedon the real-time detection software of repose angle, this paper then develop a control systemof the solids motion in rotating cylinder based on image feedback. This system consists of twomodules, image feedback control module and the motor speed control module. Imagefeedback control module according to the image feedback result, automatically set motorgiven speed; and the motor speed control module according to a given speed, automaticallyadjust the rotary drum speed with PID algorithm, eventually make solids stay in rollingmotion. This system can effectively control solids motion. It shows that, the thinking ofthrough the image testing to judge the solids motion and by adjusting the drum speed tocontrol solids motion is completely feasible, this system provides a new way of thinking toimprove the level of automatic control of rotary kiln. has the important theoretical andpractical significance.