Magnetic Levitation for Soft-Tethered Capsule Colonoscopy Actuated With a Single Permanent Magnet: A Dynamic Control Approach

The present letter investigates a novel control approach for magnetically driven soft-tethered capsules for colonoscopy—a potentially painless approach for colon inspection. The focus of this work is on a class of devices composed of a magnetic capsule endoscope actuated by a single external permanent magnet. Actuation is achieved by manipulating the external magnet with a serial manipulator, which in turn produces forces and torques on the internal magnetic capsule. We propose a control strategy which, counteracting gravity, achieves levitation of the capsule. This technique, based on a nonlinear backstepping approach, is able to limit contact with the colon walls, reducing friction, avoiding contact with internal folds, and facilitating the inspection of nonplanar cavities. The approach is validated on an experimental setup, which embodies a general scenario faced in colonoscopy. The experiments show that we can attain 19.5% of contact with the colon wall, compared to the almost 100% of previously proposed approaches. Moreover, we show that the control can be used to navigate the capsule through a more realistic environment—a colon phantom—with reasonable completion time

Motor Learning skill experiments using Haptic Interface capabilities

This paper investigated the influence that proportional feedback programmed into haptic interface (HI) can have in the development of motor skills. The haptic interface design, adapted to the task to be performed, plays a key role inside motor learning processes as the kinesthetic and proprioceptive are the information pathway in the perception of incoming stimuli. Subjects learned to draw a shape using two kinds of training methods: visual, visual and haptic. The error position distance was measured and a statistical analysis was done in order to identify user's motion improvement when training trials were alternated with practice trials. In order to constraint the user to draw a predefined path, a control law is presented

Adaptive filters for the suppression of tremor

Intention tremor severely compromises everyday life tasks in patients suffering with multiple sclerosis or Parkinson's disease. The paper reports the current achievements in the analysis of subjects' movements. The trajectories produced by patients affected by tremor are investigated. Indexing procedures for the evaluation of the tremor which is present in the trajectories are proposed. Such indexes should be sensitive to tremor while they are not to ordinary movements. The properties of the indexes have been verified both with analytical considerations and with numerical tests. An experimental setup has been realized for the analysis of tremor on patients affected by multiple sclerosis tremor. The data collected within this experiment have been compared with expected results. Furthermore the indexing procedure has been applied for the evaluation of a filtering system. The case of handwriting has been chosen as the reference task for the evaluation of achieved results. The results of clinical tests are presented. Finally the applicability of the index-based procedures to the control of filtering systems is discussed. The control architectures in the case of force-feedback less interfaces as well as haptic interfaces are presented and discusse