Keyvan Hashtrudi-Zaad

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A large number of bilateral teleoperation control architectures in the literature have been designed based on assumed impedance models of the master and slave manipulators. However, hydraulic or heavily geared and many other manipulators cannot be properly described by impedance models. In this paper, a common four-channel bilateral control architecture(More)
This paper proposes a novel four-channel multilateral shared control architecture for dual-user teleoperation systems. The proposed control architecture is designed to allow interaction between two users as well as slave and environment through a dominance factor. The dominance factor adjusts the authority of the users over the slave robot and the task. To(More)
Real-time estimates of environment dynamics play an important role in the design of controllers for stable interaction between robotic manipulators and unknown environments. The Hunt-Crossley (HC) dynamic contact model has been shown to be more consistent with the physics of contact, compared with the classical linear models, such as Kelvin-Voigt (KV). This(More)
In this paper, we study the performance of various algorithms for fast online identification of environment impedance during robotic contact tasks. In particular, we evaluate and compare algorithms with regard to their convergence rate, computational complexity and sensitivity to noise for different environments using a single degree-of-freedom experimental(More)
A new dynamic registration technique is designed to elastically align a sequence of 2-D ultrasound (US) images. The proposed algorithm tracks features over an image sequence in real-time, as opposed to our previous technique which registers images without utilizing prior information. The registration results were evaluated using a customized validation(More)
3D registration of ultrasound images is an important and fast-growing research area with various medical applications, such as image-guided radiotherapy and surgery. However, this registration process remains extremely challenging due to the deformation of soft tissue and the existence of speckles in these images. This paper presents a technique for(More)