No abstract

We present the kinematics, optimal dimensional synthesis, series-elastic actuation, control, characterization and user evaluation of AssistOn-Ankle, a reconfigurable, powered exoskeleton for ankle rehabilitation. AssistOnAnkle features reconfigurable kinematics for delivery of both range of motion (RoM)/strengthening and balance/ proprioception exercises. In particular, through lockable joints, the underlying kinematics can be configured to either a self-aligning parallel mechanism that can naturally cover the whole RoM of the human ankle, or another parallel mechanism that can support the ground reaction forces/torques transferred to the ankle. Utilizing a single device to treat multiple phases of treatment is advantageous for robotic rehabilitation, since not only does it decrease the device cost and help with the space requirements, but also shorten the time it takes for patients to familiarize with the device. Bowden cable-based series-elastic actuation of AssistOn-Ankle allows for a remote placement of the motors/drivers to result in a compact design with low apparent inertia, while also enabling high-fidelity force/impedance control and active backdriveability of the device. This is one of several papers published in Autonomous Robots comprising the "Special Issue on Assistive and Rehabilitation Robotics". B Volkan Patoglu

Original scientific paperThis work attempts to achieve motion control along with vibration suppression of flexible systems by developing a sensorless closed loop LQR controller. Vibration suppression is used as a performance index that has to be minimized so that motion control is achieved with zero residual vibration. An estimation algorithm is combined with the regular LQR to develop sensorless motion and vibration controller that is capable of positioning multi degrees of freedom flexible system point of interest to a pre-specified target position with zero residual vibration. The validity of the proposed controller is verified experimentally by controlling a sensorless dynamical system with finite degrees of freedom through measurements taken from its actuator.Key words: Sensorless control, Vibration suppression, Reaction force observer, Optimal control, Action reaction state observer Fleksibilni slijedni sustav s koncentriranim parametrima sa suzbijanjem vibracija korištenjem LQR-a bez senzora. U ovom radu opisan je fleksibilni slijedni sustav sa suzbijanjem vibracija upravljan LQR regulatorom u zatvorenom upravljačkom krugu bez senzora. Vibracije su korištene u težinskoj funkciji koja se minimizira s ciljem eliminiranja rezidualnih vibracija iz slijednog sustava. Kombinirajući algoritam estimacije s klasičnim LQRom, razvijen je regulator za upravljanje gibanjem i vibracijama bez korištenja senzora, koji je sposoban pozicionirati odreenu točku fleksibilnog sustava s više stupnjeva slobode u predefiniranu željenu točku bez preostalih vibracija. Validacija predloženog regulatora provedena je eksperimentalno upravljajući dinamičkim sustavom s konačnim brojem stupnjeva slobode uz korištenje mjerenja s aktuatora.Ključne riječi: upravljanje bez senzora, suzbijanje vibracija, observer reakcijske sile, optimalno upravljanje, observer stanja akcije i reakcije

No abstract