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Rigid grippers used in existing aerial manipulators require precise positioning to achieve successful grasps and transmit large contact forces that may destabilize the drone. This limits the speed during grasping and prevents "dynamic grasping", where the drone attempts to grasp an object while moving. On the other hand, biological systems (e.g., birds) rely on compliant and soft parts to dampen contact forces and compensate for grasping inaccuracy, enabling impressive feats. This paper presents the first prototype of a soft drone -- a quadrotor where traditional (i.e., rigid) landing gears are replaced with a soft tendon-actuated gripper to enable aggressive grasping. We provide three key contributions. First, we describe our soft drone prototype, including electro-mechanical design, software infrastructure, and fabrication. Second, we review the set of algorithms we use for trajectory optimization and control of the drone and the soft gripper; the algorithms combine state-of-the-art techniques for quadrotor control (i.e., an adaptive geometric controller) with advanced soft robotics models (i.e., a quasi-static finite element model). Finally, we evaluate our soft drone in physics simulations (using SOFA and Unity) and in real tests in a motion-capture room. Our drone is able to dynamically grasp objects of unknown shape where baseline approaches fail. Our physical prototype ensures consistent performance, achieving 91.7% successful grasps across 23 trials. We showcase dynamic grasping results in the video attachment. Video Attachment: https://youtu.be/mqbj8mEyCdk, Comment: 8 pages, 8 figures, IROS 2021. arXiv admin note: text overlap with arXiv:2004.04238

Manipulation and grasping with unmanned aerial vehicles (UAVs) currently require accurate positioning and are often executed at reduced speed to ensure successful grasps. This is due to the fact that typical UAVs can only accommodate rigid manipulators with few degrees of freedom, which limits their capability to compensate for disturbances caused by the vehicle positioning errors. Moreover, UAVs have to minimize external contact forces in order to maintain stability. Biological systems, on the other hand, exploit softness to overcome similar limitations, and leverage compliance to enable aggressive grasping. This paper investigates control and trajectory optimization for a soft aerial manipulator, consisting of a quadrotor and a tendon-actuated soft gripper, in which the advantages of softness can be fully exploited. To the best of our knowledge, this is the first work at the intersection between soft manipulation and UAV control. We present a decoupled approach for the quadrotor and the soft gripper, combining (i) a geometric controller and a minimum-snap trajectory optimization for the quadrotor (rigid) base, with (ii) a quasi-static finite element model and control-space interpolation for the soft gripper. We prove that the geometric controller asymptotically stabilizes the quadrotor velocity and attitude despite the addition of the soft load. Finally, we evaluate the proposed system in a realistic soft dynamics simulator, and show that: (i) the geometric controller is fairly insensitive to the soft payload, (ii) the platform can reliably grasp unknown objects despite inaccurate positioning and initial conditions, and (iii) the decoupled controller is amenable for real-time execution., Comment: 17 pages, 12 figures. Aeroconf 2021

Mutually beneficial behavior in repeated games can be enforced via the threat of punishment, as enshrined in game theory's well-known "folk theorem." There is a cost, however, to a player for generating these disincentives. In this work, we seek to minimize this cost by computing a "Stackelberg punishment," in which the player selects a behavior that sufficiently punishes the other player while maximizing its own score under the assumption that the other player will adopt a best response. This idea generalizes the concept of a Stackelberg equilibrium. Known efficient algorithms for computing a Stackelberg equilibrium can be adapted to efficiently produce a Stackelberg punishment. We demonstrate an application of this idea in an experiment involving a virtual autonomous vehicle and human participants. We find that a self-driving car with a Stackelberg punishment policy discourages human drivers from bullying in a driving scenario requiring social negotiation., Comment: 10 pages, The 11th International Conference on Social Robotics

A preliminary report is offered on schools that offer all or a greater part of their instruction in a language other than English. Emphasis is laid on instruction geared toward the language maintenance of ethnic communities. Language reports include the approximate number of speakers and number, distribution, and basic characteristics of schools. Some detailed reports on individual schools are included, along with a certain amount of more extensive statistical information. The language reports are supplemented by three essays: (1) "Cultural Pluralism and the American School"; (2) "Whorfianism of the Third Kind: Ethnolinguistic Diversity as a Worldwide Societal Asset"; and (3) "Why Do Some Ethnic Community Schools in the USA Accomplish More than Others with Respect to Ethnic Mother Tongue Instruction?" (JB)

This paper defines bilingual education and notes that because of bilingual education's broad definition, a number of vastly different types of programs and program goals are being pursued. Four broad categories of bilingual education programs based on four different kinds of community and school objectives are discussed in this paper. Each of these is illustrated by an existing or proposed bilingual education program for some Spanish Speaking community. Several rationales advanced for bilingual education are reviewed. Briefly discussed is the issue of how bilingual education might affect the future of language teaching and language learning in the United States. Most American bilingual education programs are viewed as academically compensatory and as socioeconomically compensatory for disadvantaged minority group children from non-English speaking families. It is noted that if bilingual education is sold as a "compensatory promissory note", teachers and citizens will be disappointed. A number of questions about bilingual education are discussed within a comparative and sociolinguistically-oriented framework. Among these are: (1) Must one language always be an "other" tongue? (2) Can the school "go it alone" for bilingual education? (3) Can community interest be too divisive for the good of bilingual education? (4) Does the world or mankind really need all those ethnic languages?. (Author/AM)

Factors that might influence the acquisition of biliteracy were studied in four schools in the Greater New York Metropolitan Area (an Armenian-English school, a Greek- English school, a Hebrew-English school, and a French- English school). This report is the final part of a two- part report and deals with the tabulation and analysis of ethnographic observations. The effect of studying two different scripts was a major concern of the research, which employed a school ethnography approach (Green and Wallat, 1981). Observational data for four grades in the four schools were coded for additional analysis. Findings include the following: (1) writing system differences were reduced by emphasizing the printing system (whether by reading or writing print), particularly in the earliest grades; (2) reading received the most attention, followed by writing, and speaking; (3) little evidence was found of either out-of-school participation in literacy acquisition or of topical emphasis on matters pertaining to home or community; (4) out-of-school influences on literacy acquisition, though small, occurred primarily for the ethnic language; (5) little awareness or concern was found for nonschool dialect, interlanguage contrasts, or interlanguage variation; (6) for instruction in French and Hebrew, teacher-made materials were more commonly employed than were basal readers, whereas the opposite was true for English instruction; (7) the Greek school stressed choral reading; (8) the French school used individual reading more than did the other schools; and (9) the Hebrew school stressed analytic decoding in both languages more than synthetic zones. (SW)

Factors that might influence the acquisition of biliteracy were studied in four schools in the Greater New York Metropolitan Area (an Armenian-English school, a Greek-English school, a Hebrew-English school, and a French-English school). This report, the first of two parts, was written after 2 years of study in which the second year was spent both on further data collection and on confirming and processing data. The effect of studying two different scripts, and societal, pedagogical, and dialectal influences were addressed. Based on ethnographic observations, it is concluded that: (1) the students seemed to read and write English at least as well as those in monoliterate schools, and were also reading another language reasonably well; (2) discrepant writing systems rarely posed difficulty for biliteracy acquisition; (3) discrepancies between the spoken and printed language did not seem to complicate biliteracy acquisition any more than they do for monoliteracy acquisition; (4) teaching methods appeared to be minor factors in literacy acquisition, relative to other variables influencing this process; (5) English literacy was valued as a key to success in the world at large and as a key to ethnic approbation and leadership; (6) the major literacy-related problem of the minority ethnic language school was not so much the acquisition of biliteracy but the maintenance of biliteracy past adolescence, particularly of the minority language; and (7) minority language literacy is related to kin and community, history, and religious rituals. (SW)