A two degrees of freedom （DOF） positioning stage using novel linear ultrasonic motors is presented. The stage mainly consists of two linear ultrasonic motors, linear guides and tables. It can realize the long stroke...A two degrees of freedom （DOF） positioning stage using novel linear ultrasonic motors is presented. The stage mainly consists of two linear ultrasonic motors, linear guides and tables. It can realize the long stroke and reversible controlled motion in two directions. The wheel-shape linear ultrasonic motor applied in the stage utilizes two fourth-bending modes of non-uniform beam in orthogonal directions. Quick response, no backlash, high resolution, power-off self-braking, and long stroke are the attractive characteristics of the linear positioning stage. Experimental results show that z and y-direction tables can reach the destination without overshoot and the error is less than 2μm by using two linear encoders with a resolution of 1 μm. In the open-loop mode, the positioning stage achieves 1μm resolution at 0. 25 ms driving time.展开更多
To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic array...To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic arrays,four stators and displacement sensors.The dynamics model of this stage was a complex nonlinear,strong coupling system which made the control strategy to be a focus research.The nonlinear controller of the system was proposed based on the theory of differential geometry.Both simulation and experimental results show that either the decoupling control of the movement can be realized in horizontal and vertical directions,and the control performance was improved by the damper,verifying the validity and efficiency of this method.展开更多
In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the infl...In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the influence of system vibration and external noise. The positioning stage is composed of voice coil motor （VCM） as macro driver and piezoelectric actuator （PEA） as micro driver. The precision of the macro drive positioning stage is improved by the com- bined PID control with adaptive Kalman filter （AKF）. AKF is used to compensate VCM vibration （as the virtual noise） and the external noise. The control scheme of the micro drive positioning stage is presented as the integrated one with PID and intelligent adaptive inverse control approach to compensate the positioning error caused by macro drive positioning stage. A dynamic recurrent neural networks （DRNN） based inverse control approach is proposed to offset the hysteresis nonlinearity of PEA. Simulations show the positioning precision of macro-micro dual-drive stage is clearly improved via the proposed control scheme.展开更多
基金the National Natural Science Foundation of China (50735002)~~
文摘A two degrees of freedom （DOF） positioning stage using novel linear ultrasonic motors is presented. The stage mainly consists of two linear ultrasonic motors, linear guides and tables. It can realize the long stroke and reversible controlled motion in two directions. The wheel-shape linear ultrasonic motor applied in the stage utilizes two fourth-bending modes of non-uniform beam in orthogonal directions. Quick response, no backlash, high resolution, power-off self-braking, and long stroke are the attractive characteristics of the linear positioning stage. Experimental results show that z and y-direction tables can reach the destination without overshoot and the error is less than 2μm by using two linear encoders with a resolution of 1 μm. In the open-loop mode, the positioning stage achieves 1μm resolution at 0. 25 ms driving time.
基金Supported by the National Natural Science Foundation of China (60674052)
文摘To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic arrays,four stators and displacement sensors.The dynamics model of this stage was a complex nonlinear,strong coupling system which made the control strategy to be a focus research.The nonlinear controller of the system was proposed based on the theory of differential geometry.Both simulation and experimental results show that either the decoupling control of the movement can be realized in horizontal and vertical directions,and the control performance was improved by the damper,verifying the validity and efficiency of this method.
基金partly supported by the National Natural Science Foundation of China(No.61174047)the School Basic Foundation of Northwestern Polytechnical University(No.GCKYI006)the Fundamental Research Funds for the Central Universities(No.HEUCFR1214)
文摘In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the influence of system vibration and external noise. The positioning stage is composed of voice coil motor （VCM） as macro driver and piezoelectric actuator （PEA） as micro driver. The precision of the macro drive positioning stage is improved by the com- bined PID control with adaptive Kalman filter （AKF）. AKF is used to compensate VCM vibration （as the virtual noise） and the external noise. The control scheme of the micro drive positioning stage is presented as the integrated one with PID and intelligent adaptive inverse control approach to compensate the positioning error caused by macro drive positioning stage. A dynamic recurrent neural networks （DRNN） based inverse control approach is proposed to offset the hysteresis nonlinearity of PEA. Simulations show the positioning precision of macro-micro dual-drive stage is clearly improved via the proposed control scheme.
