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Research On Motion Control System And Fast High-precision Positioning Technology For Wire Bonding

Posted on:2016-08-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:C LiuFull Text:PDF
GTID:1108330503993707Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
With the demands for high efficient, multi-lead, fine pitch chip packaging technology, there is an increasing need for high-acceleration linear servo system with better performance in dynamic response, positioning accuracy and time. In high-end wire bonding machine, the motion platform is required to achieve smooth and accurate positioning within several milliseconds to over ten milliseconds. However, during the high-acceleration point-to-point motions with short strokes, the positioning accuracy and time are deteriorated due to the residual vibrations caused by external disturbances,mechanical resonance modes, and nonlinear characteristics of electrical and mechanical system. Therefore, there are still tremendous challenges to design and develop high-performance motion control system.With support of the major project of Chinese National Science and Technology under Grant 2009ZX02021-003, this dissertation focuses on the research of high performance positioning technology and dedicated multi-axis control system, which are the core technology and key component for high-end wire bonding machines. Firstly,by establishing a simulation platform of high-acceleration linear servo system, the impact of external disturbances and mechanical resonance modes on positioning performance of high-acceleration linear servo system is quantitatively analyzed, and the key technologies for achieving fast and high-accuracy positioning are explored. Secondly, by considering the implementation constrains of embedded motion control system with DSP, three main technologies of model parameter identification, discrete trajectory planning and high-performance control algorithm are studied in depth. Finally, the above mentioned technologies are integrated and implemented in the self-developed embedded motion controller.The main research contents and achievements of this dissertation are summarized as follows:1. In order to analyze the impact of mechanical resonance modes on servo performance of high-acceleration linear servo system effectively, a modeling method is proposed to establish a simulation platform of high-acceleration linear servo system based on resonance modes of the mechanical platform and the electromagnetic model of linear motor. Simulations are carried out to quantitatively analyze the influence of external disturbances and mechanical resonance modes on servo performance of highacceleration linear servo system.2. To achieve fast and accurate model parameter identification, a relay shaping identification method with velocity(position) feedback is proposed in frequency domain. The problem of main harmonic approximation is effectively solved and the output responses of standard relay are filtered and shaped to be more sine-wave-like. In time domain, a standard relay time-domain identification method with position feedback is proposed to enhance the identification precision. Simulation results show that identification errors of model parameters are both within 0.05%.3. To suppress residual vibrations evoked by high acceleration motions, a trajectory planning method with the Morlet wavelet transform analysis is proposed to generate an optimized motion profile, which has lowest magnitude at natural frequency. Experimental results with a hardware-in-the-loop simulation system demonstrate that the positioning time can be reduced from 21.5 ms to 11.4 ms by effectively reducing the residual vibrations.4. A disturbance-observer-based hybrid control strategy, which is composed of a PD feedback controller based on the pole-placement design, a feed-forward controller based on the inverse-model design and a force-displacement disturbance observer, is proposed to suppress high-frequency electrical noise, internal and external disturbances. Furthermore, a new implementation of the DOB low-pass filter is designed and by suppressing the influence of resonant peaks. Experimental results show that the positioning time for a typical movement of 2.54 mm is less than 12 ms with positioning accuracy of ±2.5 μm.5. A dedicated CPCI embedded motion controller based on DSP and FPGA is developed to meet the technical requirements of motion control system of high-end wire bonding machine. Furthermore, high performance positioning algorithms proposed in this dissertation are integrated in the self-developed embedded motion controller.Experimental results verify that our motion control system is capable of realizing fast and high-precision positioning. The positioning time for a typical movement of 2.54 mm is between 12 ms to 16 ms with positioning accuracy of ±2.5 μm.Finally, further studies on embedded motion controllers and positioning technology are also discussed at the end of this dissertation.
Keywords/Search Tags:high-acceleration motion system, high-precision positioning, linear motor, relay feedback technology, residual vibrations, disturbance observer, embedded motion controller
PDF Full Text Request
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