Research On Multi-Dim Vibration Damping Device And Its Active Control Technology Based On Parallel Mechanism

Multi-dim vibration is a universal phenomenon in mechanical devices, precise instruments, equipment of vehicles and ships, aerospace equipment and so on, and it has influenced seriously the performance and work life of these equipments. There are little effective measure to solve those problems by far, so there are actual meanings and applied value to study multi-dim vibration control problem.Supported by the National Science Foundation project—Systematic theory of design and nonlinear decoupling control of multi-dim vibration absorber imitating rubber(50375067)and applied for three-dim vibration damping of vehicle seat, this paper presents a new 3-translation parallel mechanism used to the main mechanism of multi-dim vibration absorber, designed a novel hybrid-electromagnetic actuator, and build a three-dim active vibration control system. Thus we can try to find an approach to solve the problems of three-dim vibration absorber system in actual project.Firstly, a novel hybrid-electromagnetic actuator with the permanent magnet is designed, by which the operating component can realize the to-and-fro driving movement by changing the current direction of its control coil and it is more convenient to use for active vibration control. The electromagnetic force of the actuator is theoretically calculated by equivalent magnetic circuit and by the finite element respectively. The characteristic of its rigidity and damping in an active vibration isolation system are analyzed, and it is indicated that they are not only related to its structure parameters, but also to the control parameters.Secondly, a new three-translation parallel mechanism is designed to solve the problem of three-dimension vibration isolation. The kinematics of the platform is analyzed and the workspace and singularities is researched by software of MATLAB. Then the dexterity in its workspace is analyzed, rules of geometrical parameter, workspace and dexterity were studied. Then the parameter of platform is optimized. The kinematics analysis of the platform indicate that there are big workspaces in vertical direction, and the Jacobian matrix is no relative to the vertical displacement, so the parallel mechanism is meet the need of three-dimension vibration isolation, such as vehicle suspension or seat.Thirdly, it has been built the dynamical differential equation for the multi-dim vibration control system, analyzed the nature frequency and model of the system studied the dynamic sensitivity for the three-dimension vibration control system to discover the influences of the design parameter to the natural frequency, and validated it by simulations.The active control of multi-DIM vibration absorber system is introduced in this paper. Under the establishment of the dynamic state-space equation and optimal control model of the active control system, a LQG controller is designed. For uncertain parameters of multi-dim vibration control system, multi-objective the robust controller is designed. The simulation model based on Matlab/Simulink environment is built and simulated by step and random vibration excitation for three directions respectively. The simulation results showed that the active control system with feedback control achieved the better performance of three-dimension vibration isolation, especially in low frequency domain. Under the big variety of structure parameter, the robust controller showed that it was efficient and superior.Finally, for the confirmation of the theory system and simulation results, the multi-DIM active vibration control system based on DSP has been built, which includes the multi-DIM vibration absorber testing prototype, sensor system, data acquisition and processing system, controller, current driver and vibration excitation etc. The key technology such as the controller based on DSP 2812, the PWM current driver circuit and control software were designed and realized. Then, the optimal controller for the test prototype has been used for the active control. The result of experiments showed that the three-dim active vibration control system achieved the good multi-dim vibration control effect.It is creationary to combine the active control technology and parallel mechanism technology to solve multi-dim vibration absorber problem. It has simple structure and good vibration control effect that the multi-dim active vibration control system based on DSP controller designed in this paper. It has pointed a new study direction of multi-dim vibration control domain and taken on extensive theoretical and practical values in this paper.