The Experts below are selected from a list of 30096 Experts worldwide ranked by ideXlab platform
Zion Tsz Ho Tse - One of the best experts on this subject based on the ideXlab platform.
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High Speed Pneumatic Stepper Motor for MRI Applications
Annals of Biomedical Engineering, 2019Co-Authors: Brian Lawrence Boland, Bradford Wood, Zion Tsz Ho TseAbstract:Presented in this paper is an exploration into the efficacy of a plastic, four-cylinder piston pneumatic Motor designed for driving medical instruments inside magnetic resonance imaging (MRI) systems. Because of the increasing use of MRI for diagnostic and interventional purposes and the benefits that could be realized by operating with real-time MR image guidance, there exists a significant need for MRI compliant surgical devices. Some type of actuation mechanism is necessary to drive such devices. The Motor can be controlled to operate in a “step” type motion by using pneumatic valves to sequentially apply air pressure to push the piston surfaces, meaning the Motor is metal-free and does not use electricity. The stepwise nature of this piston Stepper Motor is ideal for the accurate, controlled movements required for MRI-guided interventions. The Motor was geared down by a gearbox to increase torque. Performance indices determined include output torque and achievable rotational velocity with respect to factors such as air pressure and load conditions. The Stepper Motor achieved speeds of approximately 2000 rpm, and maximum output torques of approximately 19 N mm. The Motor represents a high speed pneumatic Stepper Motor design capable of actuating devices in MR environments without affecting image quality.
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a 10 mm mr conditional unidirectional pneumatic Stepper Motor
IEEE-ASME Transactions on Mechatronics, 2015Co-Authors: Yue Chen, Christopher D Mershon, Zion Tsz Ho TseAbstract:Magnetic resonance (MR) conditional robotic devices facilitate accurate interventional procedures under MR imaging (MRI) guidance. For this purpose, a compact (10-mm diameter) MR-conditional Stepper Motor is presented. The device features seven key components, which contribute to a dense and easy to fabricate design. Alternating bursts of pressurized air and vacuum can drive the Motor in 60° per step to achieve a maximum torque of 2.4 mNm. The relationship between torque and angular speed was investigated to demonstrate Motor performance under different loading conditions. The Stepper Motor was tested in a GE 3T MRI scanner to verify its MR-compatibility. A maximum artifact width of 3 mm was measured in MRI images and a maximum signal-to-noise ratio reduction of 2.49% was recorded.
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An MR-Conditional High-Torque Pneumatic Stepper Motor for MRI-Guided and Robot-Assisted Intervention
Annals of Biomedical Engineering, 2014Co-Authors: Yue Chen, Ka-wai Kwok, Zion Tsz Ho TseAbstract:Magnetic resonance imaging allows for visualizing detailed pathological and morphological changes of soft tissue. MR-conditional actuations have been widely investigated for development of image-guided and robot-assisted surgical devices under the Magnetic resonance imaging (MRI). This paper presents a simple design of MR-conditional Stepper Motor which can provide precise and high-torque actuation without adversely affecting the MR image quality. This Stepper Motor consists of two MR-conditional pneumatic cylinders and the corresponding supporting structures. Alternating the pressurized air can drive the Motor to rotate each step in 3.6° with the Motor coupled to a planetary gearbox. Experimental studies were conducted to validate its dynamics performance. Maximum 800 mN m output torque is achieved. The Motor accuracy independently varied by two factors: Motor operating speed and step size, was also investigated. The Motor was tested within a 3T Siemens MRI scanner (MAGNETOM Skyra, Siemens Medical Solutions, Erlangen, Germany) and a 3T GE MRI scanner (GE SignaHDx, GE Healthcare, Milwaukee, WI, USA). The image artifact and the signal-to-noise ratio (SNR) were evaluated for study of its MRI compliancy. The results show that the presented pneumatic Stepper Motor generated 2.35% SNR reduction in MR images. No observable artifact was presented besides the Motor body itself. The proposed Motor test also demonstrates a standard to evaluate the pneumatic Motor capability for later incorporation with Motorized devices used under MRI.
Sergio Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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novel Stepper Motor controller based on fpga hardware implementation
IEEE-ASME Transactions on Mechatronics, 2003Co-Authors: Daniel Carrica, Marcos Funes, Sergio GonzalezAbstract:This paper proposes a novel Stepper Motor controller based on field programable gate arrays, showing a remarkable performance. The system provides a combination between a novel algorithm and programmable logic to achieve both high speed and high precision on a compact hardware.
Wilfrid Perruquetti - One of the best experts on this subject based on the ideXlab platform.
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A third order sliding mode controller for a Stepper Motor
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Michael Defoort, F. Nollet, Thierry Floquet, Wilfrid PerruquettiAbstract:This paper deals with the robust control problem of a Stepper Motor subject to parameter uncertainties and load torque perturbation. The developed algorithm is based on third-order sliding-mode control such that a desired angular Motor position is accurately tracked. The proposed scheme requires the measurement or the estimation of the Motor speed and acceleration for feedback. To avoid the use of tachometers and accelerometers which add cost and energy consumption, a robust second-order sliding-mode observer is presented. Experimental results illustrate the performance and the advantages of the proposed controller.
Zhu Min - One of the best experts on this subject based on the ideXlab platform.
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a research of a new technique on hardware implementation of control algorithm of high subdivision for Stepper Motor
Conference on Industrial Electronics and Applications, 2010Co-Authors: Yang Mengda, Zhu MinAbstract:This paper designs a new control system of high-subdivision for a Stepper Motor. through which integrated controller and driver of Stepper Motor on a FPGA chip. The problem of high-subdivision stepping angle is solved by using the technique of FPGA hardware at controllers and drivers of Stepper. The number of subdivision can reach 4096, and the step pitch angle be automatically adjusted. This system has also established a PWM generator, a PI controller and a microprocessor IP core, that may further be used of making control chip of Stepper Motors. Product with the same function, at present, which has this great performance has not been seen in any report. Experimental results indicate that the technique could improve the resolution of a Stepper Motor and make it run more smoothly.
David Stein - One of the best experts on this subject based on the ideXlab platform.
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kinematic design and commutation of a spherical Stepper Motor
IEEE-ASME Transactions on Mechatronics, 1999Co-Authors: Gregory S Chirikjian, David SteinAbstract:This paper addresses the design and commutation of a novel kind of spherical Stepper Motor in which the poles of the stator are electromagnets and the poles of the rotor (rotating ball) are permanent magnets. Due to the fact that points on a sphere can only be arranged with equal spacing in a limited number of cases (corresponding to the Platonic solids), design of spherical Stepper Motors with fine rotational increments is fundamentally geometrical in nature. We address this problem and the related problem of how rotor and stator poles should be arranged in order to interact to cause motion. The resulting design has a much wider range of unhindered motion than other spherical Stepper Motor designs in the literature. We also address the problem of commutation, i.e., we determine the sequence of stator polarities in time that approximate a desired spherical motion.
