The collaborative effort between fundamental science, engineering and medicine provides physicians with improved tools and techniques for delivering effective health care. Minimally invasive surgery (MIS) techniques have revolutionized the way a number of surgical procedures are performed. Recent advances in surgical robotics are once again revolutionizing MIS interventions and open surgery. In an earlier research endeavor, 30 surgeons performed 7 different MIS tasks using the Blue Dragon system to collect measurements of position, force, and torque on a porcine model. This data served as the foundation for a kinematic optimization of a spherical surgical robotic manipulator. Following the optimization, a seven-degree-of-freedom cable-actuated surgical manipulator was designed and integrated, providing all degrees of freedom present in manual MIS as well as wrist joints located at the surgical end-effector. The RAVEN surgical robot system has the ability to teleoperate utilizing a single bi-directional UDP socket via a remote master device. Preliminary telesurgery experiments were conducted using the RAVEN. The experiments illustrated the system’s ability to operate in extreme conditions using a variety of network settings.
This paper presents a technique for attenuating the external disturbances acting on the rotor of a prototype flywheel energy storage device. The approach uses a three-phase axial flux brushless dc motor to simultaneously produce a torque and a radial force. This is accomplished by using two phases of the motor for torque generation, and one phase to produce the radial force. The paper develops a set of equations that can be used to predict the forces generated by the motor coils. These equations are used to implement a feedback control system to suppress the effects of external excitations. The nonlinear controller requires the velocity measurements and the angular displacement of the flywheel. The controller essentially adds damping to the system, and the constant feedback gains solve an optimization problem that involves a H∞ bound on the disturbance attenuation. The experimental results clearly demonstrate that the dc motor can be used to suppress unwanted radial vibrations due to external disturbances.
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