A robust adaptive control approach is presented to improve the performance of the control scheme proposed in the authors＇ previous work, aiming at producing a low ripple hybrid stepping motor servo drive for precisio...A robust adaptive control approach is presented to improve the performance of the control scheme proposed in the authors＇ previous work, aiming at producing a low ripple hybrid stepping motor servo drive for precision profile tracking at a low speed. In order to construct a completely integrated control design philosophy to reduce torque ripple and at the same time to enhance tracking performance, the properties of nonlinear uncertainties in the system dynamics are uncovered, and then incorporated into the design of the controller. The system uncertainties concerned with ripple dynamics and other external disturbances are composed of two categories. The first category of uncertainties with linear parameterization arising from the detention effect is dealt with by the wellknown adaptive control method. A robust adaptive method is used to deal with the second category of uncertainties resulting from the non-sinusoidal flux distribution. The μ-modification scheme is used to cease parameter adaptation by the robust adaptive control law, thus ensuring that the trajectory tracking error asymptotically converges to a pre-specified boundary. Experiments are performed with a typical hybrid stepping motor to test its profile tracking accuracy. Results confirm the proposed control scheme.展开更多
We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device...We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device. The hybrid step motor is used as the actuator, which enables the finger to keep enough high contact torque on the grasped object with less energy consumption provided by the holding torque. The grasping force of the finger is estimated from the base joint torque, and the adoption of impedance control has provided compliance in the grasping. Also a parallel observer is used to switch over between the impedance control and the torque holding mode. The experimental results show the effectiveness of the design and control strategy.展开更多
A scanning probe microscope(SPM)stage controlled by three stepper motors is designed,which has more flexibilitiesthan that of one motor controlled stage,while the control whom is more complicated.In this project,we bu...A scanning probe microscope(SPM)stage controlled by three stepper motors is designed,which has more flexibilitiesthan that of one motor controlled stage,while the control whom is more complicated.In this project,we build the stageactions in an Arduino microcontroller,and finite state machine(FSM)is also built in the Arduino micro controller to communicatewith a computer and a radio frequency(RF)controller.A special displaying scheme with five states is employed to indicatethe operation of the stage.Finally,the stage is fully tested and has a700nm resolution in Z motion of the SPM.展开更多
This paper introduces a design to improve the radiotherapy accuracy of gamma knife. In this design, sensor is used to collect respiratory parameters and tumor displacement (caused by human respiration) model is establ...This paper introduces a design to improve the radiotherapy accuracy of gamma knife. In this design, sensor is used to collect respiratory parameters and tumor displacement (caused by human respiration) model is established through optimization modeling. At the same time, data are transferred to single chip microcomputer (SCM) system by pressure sensor and then stepping motor is controlled by SCM. Finally, the intelligent positioning bed is under the control of stepping motor. As a result, the intelligent positioning bed can move reverse to respiratory law. The experimental results showed that this method can reduce the influence of respiration on tumor displacement, improving the accuracy of intelligent positioning bed with simple circuit and low cost at the same time.展开更多
A tunable single-longitudinal mode erbium-doped fiber ring laser based on stepper motor and closed loop control is proposed and demonstrated. The system consists of an erbium-doped fiber （EDF）, a tunable fiber Bragg...A tunable single-longitudinal mode erbium-doped fiber ring laser based on stepper motor and closed loop control is proposed and demonstrated. The system consists of an erbium-doped fiber （EDF）, a tunable fiber Bragg grating （FBG） filter and a wavelength detector. The characteristics of output laser, such as output power, power stability and 3-dB linewidth, are investigated in the operation range of I 531-1 569 nm. The repeated experimental results of the fiber laser show that the 3-dB linewidth is less than 17 ps, the side-mode suppression ratio （SMSR） is up to 60 dB, the outout Dower is up to 1.37 dBm. and the Dower variation is less than 0.61 dR展开更多
文摘A robust adaptive control approach is presented to improve the performance of the control scheme proposed in the authors＇ previous work, aiming at producing a low ripple hybrid stepping motor servo drive for precision profile tracking at a low speed. In order to construct a completely integrated control design philosophy to reduce torque ripple and at the same time to enhance tracking performance, the properties of nonlinear uncertainties in the system dynamics are uncovered, and then incorporated into the design of the controller. The system uncertainties concerned with ripple dynamics and other external disturbances are composed of two categories. The first category of uncertainties with linear parameterization arising from the detention effect is dealt with by the wellknown adaptive control method. A robust adaptive method is used to deal with the second category of uncertainties resulting from the non-sinusoidal flux distribution. The μ-modification scheme is used to cease parameter adaptation by the robust adaptive control law, thus ensuring that the trajectory tracking error asymptotically converges to a pre-specified boundary. Experiments are performed with a typical hybrid stepping motor to test its profile tracking accuracy. Results confirm the proposed control scheme.
基金Supported by t he National Natural Science Foundation of China （ No. 50435040） and the High Technology Research and Development Programme of China（ No. 2003AA420010）.
文摘We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device. The hybrid step motor is used as the actuator, which enables the finger to keep enough high contact torque on the grasped object with less energy consumption provided by the holding torque. The grasping force of the finger is estimated from the base joint torque, and the adoption of impedance control has provided compliance in the grasping. Also a parallel observer is used to switch over between the impedance control and the torque holding mode. The experimental results show the effectiveness of the design and control strategy.
文摘A scanning probe microscope(SPM)stage controlled by three stepper motors is designed,which has more flexibilitiesthan that of one motor controlled stage,while the control whom is more complicated.In this project,we build the stageactions in an Arduino microcontroller,and finite state machine(FSM)is also built in the Arduino micro controller to communicatewith a computer and a radio frequency(RF)controller.A special displaying scheme with five states is employed to indicatethe operation of the stage.Finally,the stage is fully tested and has a700nm resolution in Z motion of the SPM.
文摘This paper introduces a design to improve the radiotherapy accuracy of gamma knife. In this design, sensor is used to collect respiratory parameters and tumor displacement (caused by human respiration) model is established through optimization modeling. At the same time, data are transferred to single chip microcomputer (SCM) system by pressure sensor and then stepping motor is controlled by SCM. Finally, the intelligent positioning bed is under the control of stepping motor. As a result, the intelligent positioning bed can move reverse to respiratory law. The experimental results showed that this method can reduce the influence of respiration on tumor displacement, improving the accuracy of intelligent positioning bed with simple circuit and low cost at the same time.
基金supported by the National Natural Science Foundation of China(No.61205014)the Natural Science Foundation of Shandong Province(No.ZR2012FL21)+3 种基金the Science&Technology Development Program of Shandong Province(No.2011YD01078)the Project of Shandong Provincial Higher Educational Science and Technology Program of China(No.J12LJ02)the Precision Instruments Upgrading Project Fund of Shandong Province(No.2012SJGZ06)the Doctoral Foundation of Shandong Province(No.BS2012DX006)
文摘A tunable single-longitudinal mode erbium-doped fiber ring laser based on stepper motor and closed loop control is proposed and demonstrated. The system consists of an erbium-doped fiber （EDF）, a tunable fiber Bragg grating （FBG） filter and a wavelength detector. The characteristics of output laser, such as output power, power stability and 3-dB linewidth, are investigated in the operation range of I 531-1 569 nm. The repeated experimental results of the fiber laser show that the 3-dB linewidth is less than 17 ps, the side-mode suppression ratio （SMSR） is up to 60 dB, the outout Dower is up to 1.37 dBm. and the Dower variation is less than 0.61 dR
