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This paper describes the methods and experiment protocols for estimation of the human ankle impedance during turning and straight line walking. The ankle impedance of two human subjects during the stance phase of walking in both dorsiflexion plantarflexion (DP) and inversion eversion (IE) were estimated. The impedance was estimated about 8 axes of rotations of the human ankle combining different amounts...
The development of variable impedance actuators (VIAs) has highlighted the need for proper control of passive impedance to attain suitable interaction performance. Until recently the regulation of the intrinsic impedance in VIAs is achieved in an open-loop model-based manner, mainly due to the lack of physical sensors capable of measuring impedance components such as stiffness and damping. Hence,...
This paper proposes a new adaptive method for two-channel bilateral teleoperation systems control; the control method consists of adaptive force feedback and motion command scaling factors that ensure stable teleoperation with maximum achievable transparency at every moment of operation. The method is based on the integration of the real time estimation of the robot's environment impedance with the...
Recently-developed variable damping mechanisms have been exploited as a complement to compliant actuators. While accurate knowledge and control of generated damping is essential for achieving the desired performance, no physical sensor measuring the damping exists. This work introduces a novel non-model-based approach for the estimation of time-variant damping for variable impedance actuation systems...
Nonlinear elasticity of transmission is indispensable in any passively variable stiffness mechanism. However, it remains obscure how to decide a desired nonlinear force-displacement function. On the other hand biological muscular actions are associated with stiffness/impedance variation in a wide range as demanded by everyday tasks. This paper addresses the issue of designing a nonlinear elastic transmission,...
Safety and dependability are of the utmost importance for physical human-robot interaction due to the potential risks that a relatively powerful robot poses to human beings. From the control standpoint, it is possible to improve safety by guaranteeing that the robot will never exhibit any unstable behavior. However, stability is not the only concern in the design of a controller for such a robot....
This paper generalizes the Time Domain Passivity Control concept originally introduced by J.-H. Ryu et al. (2004) in order to work for multi-degree of freedom (DoF) haptic systems with time delay. Its energy computation (named passivity observer) factors in the phase shift caused by time delay, and is improved by an energy estimation. Moreover, the variable damping of the passivity controller is generalized...
In a haptic teleoperation system, the incorporation of knowledge about the remote environment in the controller design can improve stability and performance. Model-mediated teleoperation adopts this idea by rendering an estimated model of the remote environment on local site instead of transmitting force/velocity flows. Thus, the user perceives locally generated forces corresponding to the estimated...
Easy operation of vehicle functionality is an important distinguishing mark for competitiveness. Recently, several approaches are presented in order to assist the entry for passengers. In this paper a novel vehicle door is proposed that increases the passengers' comfort by supporting him with additional forces while opening or closing the door but retaining the common haptic properties of a passive...
Teleoperation allows surgeons to perform an operation that is remote in distance and/or scale. Extracting information about a patient, particularly the dynamic model of tissues, during a surgical procedure may be useful for improving telemanipulator control, developing simulations, and performing automated diagnosis. This study examines automated environment parameter identification methods for bilateral...
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