Dynamics and control of coordinated multiple manipulators

A technique is presented for controlling multiple manipulators which are holding a single object and therefore form a closed kinematic chain. The object, which may or may not be in contact with a rigid environment, is assumed to be held rigidly by robot end-effectors. The derivation is based on setting up constraint equations which reduce the 6 x n degrees of freedom of a manipulators each having six joints. Additional constraint equations are considered when one or more of the degrees of freedom of the object is reduced due to external constraints. Utilizing the operational space dynamics equations, a decoupling controller is designed to control both the position and the interaction forces of the object with the environment. Finally, simulation results for the control of a pair of two-link manipulators are presented

A Wilkinson Power Divider with Harmonic Suppression and Size Reduction using High-low Impedance Resonator Cells

A miniaturized Wilkinson power divider using high-low impedance resonator cells are designed and fabricated. The proposed power divider occupies 23.7% of the conventional structure circuit area at the operating frequency of 0.9 GHz and it is also able to suppress harmonics. According to the measured results at 0.9 GHz, the insertion-losses of output ports are 3.087 dB, the return-losses at all ports are more than 30 dB, and the isolation between output ports is better than 35 dB. Also, 2nd to 10th spurious frequencies are suppressed. According to the measured S11, when it is less than -15 dB (from 0.65 GHz to 1.1 GHz) the fractional bandwidth of the proposed structure is 50%. Good agreement between simulation and measured results is achieved

Bilevel shared control for teleoperators

A shared system is disclosed for robot control including integration of the human and autonomous input modalities for an improved control. Autonomously planned motion trajectories are modified by a teleoperator to track unmodelled target motions, while nominal teleoperator motions are modified through compliance to accommodate geometric errors autonomously in the latter. A hierarchical shared system intelligently shares control over a remote robot between the autonomous and teleoperative portions of an overall control system. Architecture is hierarchical, and consists of two levels. The top level represents the task level, while the bottom, the execution level. In space applications, the performance of pure teleoperation systems depend significantly on the communication time delays between the local and the remote sites. Selection/mixing matrices are provided with entries which reflect how each input's signals modality is weighted. The shared control minimizes the detrimental effects caused by these time delays between earth and space

PERSENTASE PEMUTIHAN KARANG (CORAL BLEACHING) DI PERAIRAN KRUENG RAYA, ACEH BESAR

ABSTRAKPemutihan karang terjadi pada beberapa wilayah secara bersamaan yang diakibatkan oleh kenaikan suhu permukaan laut melalui fenomena perubahan iklim global. Perairan Krueng Raya, Aceh Besar merupakan salah satu wilayah yang terkena dampak tersebut. Penelitian ini menerangkan tentang persentase indeks pemutihan karang di Perairan Krueng Raya Aceh besar pada 3 stasiun penelitian yaitu Lhok Me, Ahmad Rhang Manyang dan Inong Balee. Perairan Krueng Raya mengalami pemutihan karang sebesar 55,5% . Pada bulan Juni 2016, indeks pemutihan tertinggi terjadi pada stasiun Inong Balee sebesar 79,44% dan indeks pemutihan terendah terjadi pada stasiun Ahmad Rhang Manyang sebesar 41,32% . Pada bulan Agustus 2016, indeks pemutihan tertinggi terjadi pada stasiun Lhok Me sebesar 94,93% dan indeks pemutihan terendah pada stasiun Ahmad Rhang Manyang sebesar 28,64%. Hasil penelitian ini menunjukkan bahwa suhu merupakan salah satu penyebab pemutihan karang. Tak hanya itu, letak geografis wilayah serta struktur tatanan karang juga mempengaruhi pemutihan karang.Kata kunci : Pemutihan karang, Terumbu karang, Suhu, Perubahan iklim, Indeks Pemutihan Karan

Pengaruh Metode Copy the Master Terhadap Kemampuan Menulis Cerita Pendek Oleh Siswa Kelas Xsma Nusantara Lubukpakam T.p 2012/2013

Penelitian ini bertujuan untuk mendeskripsikan ada Pengaruh Metode Copy The Master terhadap kemampuan menulis cerpen siswa kelas X SMA Nusantara LubukPakam Tahun Pelajaran 2012/2013. Populasi penelitian ini adalah seluruh siswa kelas X SMA Nusantara LubukPakam yang berjumlah 207 orang dan yang menjadi sampel pada penelitian ini sebanyak 34 orang yaitu sampel yang sudah diacak. Metode penelitian ini adalah metode eksperimen dengan model one group pre-testand post-test design. Instrumen yang digunakan adalah tes menulis cerpen dalam bentuk essai, peneliti menugaskan siswa untuk menulis cerpen. Dari hasil analisis data diketahui bahwa ada perbedaan antara sebelum mendapat perlakuan dan sesudah mendapat pelakuan pada siswa kelas X SMA Nusantara LubukPakam. Tanpa menggunakan metode CopyThe Mastermemiliki Mean =63,67 Standar Deviasi = 6,57 dan Standar Error = 1,22. Metode Copy The Mastermemiliki Mean = 78,50 Standar Deviasi = 6,60 dan Standar Error = 1,23. Berdasarkan perhitungan uji normalitas, deketahui bahwa pada X diperoleh harga L0 (Lhitung) = 0,1540 dan Lt (Ltabel) = 0,1610. Ternyata Lhitung ttabel­ (8,57 > 2,04) pada taraf signifikan 5% dan (8,57 > 2,04) pada taraf signifikan 1%, maka hipotesis nihil (H) ditolak dan hipotesis alternatif (Ha) diterima. Dapat disimpulkan bahwa Pengaruh Metode Copy The Masterterhadap kemampuan menulis cerpen lebih efektif

Method and apparatus for hybrid position/force control of multi-arm cooperating robots

Two or more robotic arms having end effectors rigidly attached to an object to be moved are disclosed. A hybrid position/force control system is provided for driving each of the robotic arms. The object to be moved is represented as having a total mass that consists of the actual mass of the object to be moved plus the mass of the moveable arms that are rigidly attached to the moveable object. The arms are driven in a positive way by the hybrid control system to assure that each arm shares in the position/force applied to the object. The burden of actuation is shared by each arm in a non-conflicting way as the arm independently control the position of, and force upon, a designated point on the object

A Study on the Effect of Scaffolding through Joint Construction Tasks on the Writing Composition of EFL Learners

The present study is an attempt to investigate the effect of scaffolding writing proficiency through joint construction tasks on the writing composition of Iranian EFL learners and to investigate any significant difference in the writing proficiency of the girls and boys after receiving the instruction. To this end, sixty intermediate learners of English, majoring in Literature and Translation, studying at Shahid Chamran University of Ahvaz participated in the research and then were randomly divided into two groups, the experimental and the comparison. During the course of this study, i.e. 10 sessions, the participants were assigned to write compositions of about 150 words on eight writing topics. To find out whether there is any significant difference in the writing proficiency of the learners who receive join construction instruction, two tests were used to compare the writing performances of the groups: a pretest prior and a posttest. Results of the Data analysis indicated that there is a significant difference in the writing proficiency of the learners who receive join construction instruction. The results also showed that, as far as the instruction on joint construction was concerned, females outperformed the males. Key words: Scaffolding; Joint Construction Task; Composition; Writin