Dexterous grasping of novel objects from a single view

In this thesis, a novel generative-evaluative method was proposed to solve the problem of dexterous grasping of the novel object with a single view. The generative model is learned from human demonstration. The grasps generated by the generative model are used to train the evaluative model. Two novel evaluative network architectures are proposed. The evaluative model is a deep evaluative network that is trained in the simulation. The generative-evaluative method is tested in a real grasp data set with 49 previously unseen challenging objects. The generative-evaluative method achieves a success rate of 78% that outperforms the purely generative method, that has a success rate of 57%. The thesis provides insights into the strengths and weaknesses of the generative-evaluative method by comparing different deep network architectures

Grasping Objects with Environmentally Induced Position Uncertainty

Due to noisy motor commands and imprecise and ambiguous sensory information, there is often substantial uncertainty about the relative location between our body and objects in the environment. Little is known about how well people manage and compensate for this uncertainty in purposive movement tasks like grasping. Grasping objects requires reach trajectories to generate object-fingers contacts that permit stable lifting. For objects with position uncertainty, some trajectories are more efficient than others in terms of the probability of producing stable grasps. We hypothesize that people attempt to generate efficient grasp trajectories that produce stable grasps at first contact without requiring post-contact adjustments. We tested this hypothesis by comparing human uncertainty compensation in grasping objects against optimal predictions. Participants grasped and lifted a cylindrical object with position uncertainty, introduced by moving the cylinder with a robotic arm over a sequence of 5 positions sampled from a strongly oriented 2D Gaussian distribution. Preceding each reach, vision of the object was removed for the remainder of the trial and the cylinder was moved one additional time. In accord with optimal predictions, we found that people compensate by aligning the approach direction with covariance angle to maintain grasp efficiency. This compensation results in higher probability to achieve stable grasps at first contact than non-compensation strategies in grasping objects with directional position uncertainty, and the results provide the first demonstration that humans compensate for uncertainty in a complex purposive task

Grasp input optimization taking contact position and object information uncertainties into consideration

This paper presents a novel approach for grasp optimization considering contact position and object information uncertainties. In practice, it is hard to grasp an object at the designated or planned contact positions, as errors in measurement, estimation, and control usually exist. Therefore, we first formulate the influences of contact uncertainties on joint torques, contact wrenches, and frictional condition. We then include external wrench uncertainties in the required external wrenches set. Based on this formulation, we define the linear grasp optimization problem for two kinds of frictional contact modelsfrictional point contact and soft finger contactso that we can successfully grasp an object even if deviations in contact point, object weight, and center of mass occur. The validity of our approach is shown by means of numerical examples and the result of experiments. © 2004-2012 IEEE

Nonprehensile Dynamic Manipulation: A Survey

Nonprehensile dynamic manipulation can be reason- ably considered as the most complex manipulation task. It might be argued that such a task is still rather far from being fully solved and applied in robotics. This survey tries to collect the results reached so far by the research community about planning and control in the nonprehensile dynamic manipulation domain. A discussion about current open issues is addressed as well

Dexterous grasping under shape uncertainty

An important challenge in robotics is to achieve robust performance in object grasping and manipulation, dealing with noise and uncertainty. This paper presents an approach for addressing the performance of dexterous grasping under shape uncertainty. In our approach, the uncertainty in object shape is parameterized and incorporated as a constraint into grasp planning. The proposed approach is used to plan feasible hand con gurations for realizing planned contacts using different robotic hands. A compliant nger closing scheme is devised by exploiting both the object shape uncertainty and tactile sensing at ngertips. Experimental evaluation demonstrates that our method improves the performance of dexterous grasping under shape uncertainty

Becoming individuals: processes of individualization and reflexivity

The article aims to show how young adults (starting with empirical research in Italy, but with the aspiration to highlight more diffuse phenomena among youth growing in the constant experience of the ‘crisis’) face the widespread injunction to be active, creative, flexible, and independent, that is, to be entrepreneurs of themselves. Young people born at the end of the last century have grown up in the midst of continuous crises – economic, health, and geopolitical – which have accentuated the tension between the social drive for personal autonomy and a growing awareness of the inability to individually solve problems that are systemic. Although the pressure to develop an entrepreneurial self and to internalize the drive for individualization may overlap with the development of a form of individualism, they can also promote new forms of sociation, based on sharing and cooperation. These forms are strongly supported by dialogical reflexivity, that is, by social conditions that promote processes of innovation and change stemming from common actions and constant confrontation with different points of view. Introducing the concept of dialogic reflexivity, the article analyses the practices that young adults put in place to support forms of individualization released from mere individualism and how social research and public policies can foster reflexive processes and create favourable conditions for youth participation and inclusion.O artigo pretende mostrar como os jovens adultos (começando com pesquisas empíricas na Itália, mas com a aspiração de destacar fenômenos mais difusos entre os jovens que crescem na experiência constante da ‘crise’) enfrentam a injunção generalizada de serem ativos, criativos, flexíveis e independentes, ou seja, serem empreendedores de si mesmos. Os jovens nascidos no final do século passado cresceram em meio a crises contínuas – econômicas, de saúde e geopolíticas – que acentuaram a tensão entre o impulso social pela autonomia pessoal e uma consciência crescente da incapacidade de resolver individualmente os problemas que são sistêmicos. Embora a pressão para desenvolver um eu empreendedor e internalizar o impulso para a individualização possa se sobrepor ao desenvolvimento de uma forma de individualismo, eles também podem promover novas formas de sociabilidade, baseadas no compartilhamento e na cooperação. Essas formas são fortemente sustentadas pela reflexividade dialógica, ou seja, por condições sociais que promovem processos de inovação e mudança a partir de ações comuns e confronto constante com diferentes pontos de vista. Apresentando o conceito de reflexividade dialógica, o artigo analisa as práticas que os jovens desenvolvem para apoiar formas de individualização libertas do mero individualismo e como a pesquisa social e as políticas públicas podem fomentar processos reflexivos e criar condições favoráveis à participação e inclusão juvenil