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The attitude tracking problem of uncertain rigid spacecraft without angular velocity measurements is addressed in this paper. The adaptive control law, which incorporates a velocity-generating filter from attitude measurements, is shown to ensure the asymptotic convergence of the attitude and angular velocity tracking errors despite unknown spacecraft inertia. Simulation results are presented to illustrate the theoretical results.

Even as mobile devices have become increasingly powerful and popular among learners and instructors alike, research involving their comprehensive integration into educational laboratory activities remains largely unexplored. 1.1 This paper discusses efforts to integrate vision-based measurement and control, augmented reality (AR), and multi-touch interaction on mobile devices in the development of Mixed-Reality Learning Environments (MRLE 1) that enhance interactions with laboratory test-beds for science and engineering education. A learner points her device at a laboratory test-bed fitted with visual markers while a mobile application supplies a live view of the experiment augmented with interactive media that aid in the visualization of concepts and promote learner engagement. As the learner manipulates the augmented media, her gestures are mapped to commands that alter the behavior of the test-bed on the fly. Running in the background of the mobile application are algorithms performing vision-based estimation and wireless control of the test-bed. In this way, the sensing, storage, computation, and communication (SSCC 2) capabilities of mobile devices are leveraged to relieve the need for laboratory-grade equipment, improving the cost-effectiveness and portability of platforms to conduct hands-on laboratories. 1.1 We hypothesize that students using the MRLE platform demonstrate improvement in their knowledge of dynamic systems and control concepts and have generally favorable experiences using the platform. To validate the hypotheses concerning the educational effectiveness and user experience of the MRLEs, an evaluation was conducted with two classes of undergraduate students using an illustrative platform incorporating a tablet computer and motor test-bed to teach concepts of dynamic systems and control. Results of the evaluation study validate the hypotheses. 2.2 The benefits and drawbacks of the MRLEs observed throughout the study are discussed with respect to the traditional hands-on, virtual, and remote laboratory formats. 1.1

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