Controlled And Composite Synchronizations In The Vibrating System Driven By Multi-Motors

Vibrating machines are a type of machines by utilizing vibrating principle to perform various processing tasks and have been widely used in various fields in industries,such as coal,steel,metallurgy,mining,architecture and environmental protection.Although the development of vibrating machines is not a popular industry,their applications in various industries are inevitable.Recently,as the requirements of energy-saving,emission reduction,green and intelligent manufacturing in modern industries are put forward,the high efficient,energy-saving,clean,large-sized and intelligentized vibrating machines,especially vibrating screens,are required.Self-synchronous vibrating machines based on vibratory synchronization theory have been widely used in various engineering fields.However,because of the limitation of their natural characteristics,there have some problems in engineering,such as the poor process effect of some vibrating machines driven by two eccentric rotors(ERs)and unable application of self-synchronous vibrating machines driven by three or four ERs in engineering.In order to solve such problems,adopting controlled synchronization to replace vibratory synchronization is a good choice.To satisfy the requirements of the high efficient,energy-saving,clean,large-sized and intelligentized vibrating machines and solve problems of self-synchronous vibrating machines,the research named controlled and composite synchronizations in the vibrating system driven by multi-motors is operated with the supports of National Natural Science Foundation of China(NSFC)and 973 projects.On basis of analysis of limitations of various self-synchronous vibrating machines driven by two or multi-motors,a controlled synchronization method is proposed.Moreover,combining vibratory synchronization and controlled synchronization,an innovative composite synchronization method is proposed.Design the test prototype,controlled and composite synchronization methods are verified by experiments.Additionally,a set of theoretical system and framework on controlled and composite synchronization theories is established.Finally,the research results are used to solve three engineering problems.The main contents and innovative achievements are follows:1.In introduction,the research status and methods of vibratory synchronization in the vibrating machines and controlled synchronization in other mechanical fields are generally summarized and three actual problems in engineering solved in this paper are listed.2.Controlled synchronizations of two and three eccentric rotors(ERs)rotating in the same direction driven by induction motors and four ERs rotating not in the same direction in far resonant vibrating systems are investigated.By using small parameter average perturbation method,the synchronization and stability conditions of implementing vibratory synchronous motion of two and multi-ERs are deduced.The disadvantages of vibratory synchronization method are found.The controlled synchronization method is proposed by employing vector control,sliding mode control(SMC)and adaptive sliding mode control(ASMC)algorithms.The stability of the controllers is proved by Lyapunov theorem and Barbalat’s lemma.From the numerical simulation results,two and multi-ERs can operate synchronous motion with zero phase differences,which indicate the controlled synchronization method is feasible.Additionally,the effects of various uncertainties including internal parameter perturbations and external disturbances on the control system are discussed,which indicate the proposed controllers have a good robustness.Finally,design the test prototype and control system,the feasibility of the proposed controllers is verified by experiment.For the vibrating system driven by two ERs in a far resonance,according to vibratory synchronization theory,if the distance between the axes of two ERs is larger than(?)times of the equivalent rotating radius of system,two ERs can operate vibratory synchronous motion with zero phase difference and the system can implement the approximate circle motion,where the efficiency of the vibrating system reaches the best.But if the distance between the axes of two ERs is smaller than(?)times of the equivalent rotating radius of system,the synchronous motion with zero phase differences cannot be implemented and the system implement the pendulum motion leading to the low efficiency.For this case,two ERs can operate synchronous motion with zero phase difference by employing the proposed controlled synchronization method and the efficiency is also improved.In engineering,the poor technological effect of the world’s largest vibrating screen is improved by using the proposed controlled synchronization method.For the vibrating system driven by three ERs in a far resonance,according to vibratory synchronization theory and experiment,compared with vibrating system driven by two ERs with zero phase difference,the increasing of number of motors will decreases the amplitude of the system,which decrease the tefficiency of the system.The purpose to increase amplitude of the system cannot be realized by increasing the power,which indicates vibrating machines driven by three ERs based on vibratory synchronization theory cannot be used in engineering.By using the proposed controlled synchronization method,three ERs operate synchronous motion with zero phase differences and the system works with approximate circle motion,which improves the efficiency.And compared with vibrating system driven by two ERs with zero phase difference,the amplitude and efficiency increase largely.The proposed controlled synchronization method can be applied to three axes vibrating screen to make it can be applied in the engineering.For the vibrating system driven by four ERs in a far resonance,from the experimental results of vibratory synchronization,four ERs cannot operate synchronous motion with zero phase differences,the resultant force acting on system are approximately equal to zero and the amplitude of system is also almost equal to zero,which indicate self-synchronous vibrating machines driven by four ERs based on vibratory synchronization cannot be used.However,by using the proposed controlled synchronization method,four ERs operate synchronous motion with zero phase differences and the body vibrates in line.The simulation and experimental results verify the feasibility of the proposed method.Based on the proposed controlled synchronization method,the large-size linear vibrating conveyor,vibrating feeder,vibrating screen and other vibrating machines can be designed to satisfy the requirements of large size and intelligence.3.On the basis of the above theoretical investigated results on controlled synchronization of two and multi-ERs in a far resonant vibrating system,combining vibratory synchronization and controlled synchronization,composite synchronizations of three and four ERs in a far resonant vibrating system are studied.Based on controlled synchronization of two ERs,by using small parameter average perturbation method,a method to implement composite synchronous motion of three and four ERs in a vibrating system is proposed.The synchronization and stability conditions are obtained.The influences of system parameters on composite synchronous motion are discussed by numerical simulation,which provides theoretical reference for design of composite synchronous vibrating machines driven by three and four ERs.Designing a test prototype and control system,the experiments are operated to verify the feasibility of composite synchronization theory.Compared with the controlled synchronization method,the design of control system is simplified and the cost of production is reduced.But for vibratory synchronization,the composite synchronization will be influenced by the natural characteristics of system.Based on composite synchronization,three axes vibrating screen can be used in the other way and large-sized four ERs driving linear vibrating machines are designed.Finally,some brief conclusions are presented and the further works are listed.