Stability analysis of haptic interfaces for different types of sampled signals and virtual environment implementations

Author(s):  
Amir Haddadi ◽  
Keyvan Hashtrudi-Zaad
1998 ◽  
Vol 25 (1) ◽  
pp. 64-67 ◽  
Author(s):  
René Verry

Susan Lederman (SL) is an invited member of the International Council of Research Fellows for the Braille Research Center and a Fellow of he Canadian Psychology Association. She was also an Associate of the Canadian Institute for Advanced Research in the Robotics and Artificial Intelligence Programme for 8 years. A Professor in the Departments of Psychology and Computing & Information Science at Queen's University at Kingston (Ontario, Canada), she has written and coauthored numerous articles on tactile psychophysics, haptic perception and cognition, motor control, and haptic applications in robotics, teleoperation, and virtual environments. She is currently the coorganizer of the Annual Symposium a Haptic Interfaces for Teleoperation and Virtual Environment Systems. René Verry (RV) is a psychology professor at Millikin University (Decatur, IL), where she teaches a variety of courses in the experimental core, including Sensation and Perception. She chose the often-subordinated somatic senses as the focus of her interview, and recruited Susan Lederman as our research specialist.


Author(s):  
A.I. Zagranichny

The article presents the results of a research of different types of activity depending on the frequency of transfer of social activity from the real environment to the virtual environment and vice versa. In the course of the research the following types of activity were identified: play activity; educational activity; work; communicative activity. 214 respondents from the following cities participated in the research: Balakovo, Saratov, Moscow. They were at the age of 15 to 24 years. 52% of them were women. They had the following social statuses: "pupil", "student", "young specialist". The correlation interrelation between the specified types of activity and the frequency of transfer of social activity from one environment into another has been analyzed and interpreted. In the course of the research the following results were received: the frequency of transfer of social activity from the real environment to the virtual environment has a direct positive link with such types of activity as play activity (r=0.221; p <0.01); educational activity (r=0.228; p <0.01) and communicative activity (r=0.346; p <0.01). The frequency of transfer of social activity from the virtual environment to the real one has a direct positive link only with two types of activity: educational activity (r=0.188; p <0.05) and communicative activity (r=0.331; p <0.01).


2018 ◽  
Vol 18 (2) ◽  
pp. 30-57
Author(s):  
Shamima Yasmin

This paper conducts an extensive survey on existing Virtual Reality (VR)-based rehabilitation approaches in the context of different types of impairments: mobility, cognitive, and visual. Some VR-based assistive technologies involve repetitions of body movements, some require persistent mental exercise, while some work as sensory substitution systems. A multi-modal VR-based environment can incorporate a number of senses, (i.e., visual, auditory, or haptic) into the system and can be an immense source of motivation and engagement in comparison with traditional rehabilitation therapy. This survey categorizes virtual environments on the basis of different available modalities. Each category is again subcategorized by the types of impairments while introducing available devices and interfaces. Before concluding the survey, the paper also briefly focuses on some issues with existing VR-based approaches that need to be optimized to exploit the utmost benefit of virtual environment-based rehabilitation systems .


2014 ◽  
Vol 11 (03) ◽  
pp. 1450020 ◽  
Author(s):  
John Fasoulas ◽  
Michael Sfakiotakis

This paper presents a general dynamic model that describes the two-dimensional grasp by two robotic fingers with soft fingertips. We derive the system's kinematics and dynamics by incorporating rolling constraints that depend on the deformation and on the rolling distance characteristics of the fingertips' material. We analyze the grasp stability at equilibrium, and conclude that the rolling properties of the fingertips can play an important role in grasp stability, especially when the width of the grasped object is small compared to the radius of the tips. Subsequently, a controller, which is based on the fingertips' rolling properties, is proposed for stable grasping concurrent with object orientation control. We evaluate the dynamic model under the proposed control law by simulations and experiments that make use of two different types of soft fingertip materials, through which it is confirmed that the dynamic model can successfully capture the effect of the fingertips' deformation and their rolling distance characteristics. Finally, we use the dynamic model to demonstrate by simulations the significance of the fingertips' rolling properties in grasping thin objects.


Author(s):  
Gonca Telli Yamamoto

Organizations and people, whenever they need to, aim to fulfill their requirements with suitable products and services. The suppliers of these requirements perform a certain marketing process until the requirement is fulfilled. In this process, first the attributes of the product or service are determined. Various studies are made during the identification of these attributes. These studies are evaluated from the customer’s perspective for conformity to taste, functionality, suitability to place and culture, convenience for budget and time. The purchasing process is concluded upon the final decision of the people or organizations that see the suitability of the product to fulfill their requirements. In this context, the mobile customer tries to cover his or her requirements with the knowledge based on information obtained from the virtual environment, and reaches facts via virtual data, and the customer creates a new structure with different features. This section aims to detail the changing customer structure, the individualization and the experienced changes and considers the transformation of individuals into mobile customers. Generations who depended on products of high-technology development, which show themselves with different aspects, have also brought differences to marketing. They have both changed the production and service approach, and began to benefit from different types of products and services. In addition to other environmental conditions that affect life, human generations who change due to the effects of the means of the age should also be examined in this context.


2018 ◽  
Vol 28 (09) ◽  
pp. 1850116 ◽  
Author(s):  
A. M. Yousef ◽  
S. M. Salman ◽  
A. A. Elsadany

A discrete predator–prey model with delayed density dependence in the rate of growth of the prey is considered. In particular, we analyze the model presented by Kot [2005] which consists of three coupled difference equations and contains two parameters. Existence and local stability analysis of fixed points of the model are addressed. The normal form technique and perturbation method are applied to the different types of bifurcations that exist in the model being investigated. It is proved that the existence of transcritical and Neimark–Sacker bifurcations can occur in the model. In addition, the chaotic behavior of the model in the sense of Marotto is proved. To verify the results obtained analytically, we perform numerical simulations which also explore further the richer dynamics of the model.


Author(s):  
Levi C. Leishman ◽  
Daniel J. Ricks ◽  
Mark B. Colton

Compliant mechanisms have the potential to increase the performance of haptic interfaces by reducing the friction and inertia felt by the user. The net result is that the user feels the dynamic forces of the virtual environment, without feeling the dynamics of the haptic interface. This “transparency” typically comes at a cost — compliant mechanisms exhibit a return-to-zero behavior that must be compensated in software. This paper presents a step toward improving the situation by using statically balanced compliant mechanisms (SBCMs), which are compliant devices that do not exhibit the return-to-zero behavior typical with most compliant mechanisms. The design and construction of a prototype haptic device based on SBCMs is presented, along with its mathematical model derived using the pseudo-rigid body model (PRBM) approach. Experimental results indicate that SBCMs effectively eliminate the return-to-zero behavior and are a feasible design element in haptic interfaces.


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