Dual Arm Research Articles

Design and Performance Evaluation of Lightweight Dual Arm Robot Featuring Hollow Shaft Servo Assembly

Design and Performance Evaluation of Lightweight Dual Arm Robot Featuring Hollow Shaft Servo Assembly

물체의 효율적인 이송을 위한 양팔 로봇의 최적 자세

This paper proposes an optimal posture for the task-oriented movement of dual arm manipulator. A stability criterion function which consists of three kinds of feature-representative parameters has been utilized to define the optimal posture. The first parameter is the force which is applied to the object. The torque of each joint and position of arm are attained from the current sensor and encoder, respectively. From these two data, the applied force to an object is estimated using sum of vectors of the joint torques estimated from the measured current. In order to investigate the robustness of each posture, the variation of the end-effector from the encoder information has been utilized as the second parameter. And for the last parameter for the optimality, the total energy consumption has been used. The total consuming energy of each posture can be computed from the current information and the battery voltage. The proposed robot structure consists of a mobile inverted pendulum and dual manipulators. In order to define the optimal posture for the each object, external disturbances are applied to the mobile inverted pendulum robot and the first and second parameters are investigated to find the optimal posture among the pre-selected most representative postures. Finally, the proposed optimal posture has been verified by the proposed stability criterion function which consists of total force to the object, the fluctuation of the end-effector position, and total energy consumption. The effectiveness of the proposed algorithms has been verified and demonstrated through the practical simulations and real experiments.

MIMO fuzzy sliding mode controlled dual arm robot in load transportation

The control problem of the cooperative motion of a two-link dual arm robot during handling and transportation of an object was studied in this paper. Since these types of robots are frequently preferred for hazardous applications such as transportation of radioactive materials and disposal of explosives, a robust non-chattering sliding mode controller (SMC) improved by a multiple-input multiple-output (MIMO) fuzzy logic unit was applied to the robot to track the desired trajectory with high accuracy and transport the load safely. In order to assess the performance of the proposed MIMO fuzzy sliding mode controller (MIMO-FSMC) in presence of parameter variations and external disturbances, a sudden load variation and noise were introduced to the robot system. If compared with classical SMC, tracking errors with smaller magnitudes and faster convergence to zero were obtained by using the proposed MIMO-FSMC. Numerical results suggest that this type of control method may safely be used for cooperative motion control of dual arm robots in load handling and transport applications in hazardous environments with high accuracy.

The detection of pesticides in water using ZnCdSe quantum dot films

This paper reports an attempt to develop a sensor system for detecting pesticides based on the effect of an analyte on the photoluminescence (PL) intensity of ZnCdSe quantum dot (QD) films. The ZnCdSe QDs were synthesized using a wet-chemical process. The sensor system comprises an excitation light source made of a laser diode, a dual arm fibre optic probe, a spectrometer and a sensor chamber. The QD films were deposited by dropping QD solution onto the probe surface and drying them at ambient temperature. The pesticides used in this study were Dipel, Siven 85% WP and Water-Dispersible Granules WG insecticides. The detection of pesticides was done by comparing the photoluminescence (PL) spectra of the films dipped in the deionized water and in pesticide solutions by varying the concentration of the pesticide solutions from 2.5 to 2500 μg l −1. It was observed that the PL intensity of the films was quenched by the presence of the pesticide molecules. The quenching degree increased with the concentration of the pesticide solutions. There is a linear relationship between the pesticide solution concentrations and the QD film sensor sensitivities. The sensitivity of the sensor system depended on the type of pesticides successively from the highest to lowest sensitivity in the order Siven 85% WP, Dipel and Water-Dispersible Granules WG. The QD films could be used as fluorescence sensors to detect water that is contaminated by pesticides.

The Relationship Between Attenuated Plaque Identified by Intravascular Ultrasound and No-Reflow After Stenting in Acute Myocardial Infarction: The HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

The aim of this study was to understand the impact of attenuated plaque on distal embolization during stent implantation in patients with acute myocardial infarction (AMI). Attenuated plaques identified by grayscale intravascular ultrasound (IVUS) might predict transient deterioration in coronary flow and/or no-reflow during percutaneous coronary intervention (PCI). We analyzed clinical, angiographic, and IVUS data from 364 patients (n = 364 infarct-related arteries) enrolled in the randomized HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial. No-reflow was final Thrombolysis In Myocardial Infarction (TIMI) flow grade ≤2 in the absence of mechanical obstruction. Attenuated plaque was hypoechoic or mixed atheroma with ultrasound attenuation without calcification. A mean attenuation score was created by measuring the angle of attenuation each 1 mm, scoring the angle as 1 to 4 (corresponding to <90°, 90° to 180°, 180° to 270°, or 270° to 360°, respectively), summing the scores, and normalizing for analysis length. Overall, 284 (78.0%) patients had attenuated plaques; no-reflow occurred in 37 (10.2%). Patients with no-reflow had a higher mean attenuation score (median [interquartile range] 2.2 [0.0 to 2.8] vs. 1.3 [0.7 to 1.8], p < 0.001), lower baseline left ventricular ejection fraction (52.8% [43.2% to 61.5%] vs. 61.4% [52.2% to 68.1%], p = 0.002), and more baseline angiographic thrombus (89.2% vs. 74.1%, p = 0.043) with no differences in post-PCI stent expansion versus patients without no-reflow. Multivariate analysis indicated that mean attenuation score was the strongest predictor of no-reflow. The mean attenuation score that best predicted no-reflow was ≥2 points (90° to 180°, sensitivity of 81.5%, and specificity of 80.5%). Attenuated plaque was present in three-quarters of patients with AMI. The amount of attenuated plaque strongly correlated with no-reflow; the larger the attenuated plaque, the greater the likelihood of no-reflow. (Dual Arm Factorial Randomized Trial in Patients w/ST Segment Elevation AMI to Compare the Results of Using Anticoagulation With Either Unfractionated Heparin + Routine GP IIb/IIIa Inhibition or Bivalirudin + Bail-out GP IIb/IIIa Inhibition; and Primary Angioplasty with stent implantation with Either a Slow Rate-release Paclitaxel-eluting Stent [TAXUS™] or Uncoated Bare Metal Stent [EXPRESS2™]; NCT00433966).

Tetrakis(trimethylsilyl)silane: Temperature dependence of vapor pressure, kinetics, and silicon carbide thin films by plasma-assisted liquid injection chemical vapor deposition process

Thermal stability, vapor pressure, enthalpy of sublimation and activation energy of tetrakis(trimethylsilyl)silane (TMSS) were investigated by non-isothermal and isothermal thermogravimetric (TG) analysis, which revealed good thermal stability, high volatility with a nil residue. The temperature dependence of vapor pressure measured by using a horizontal dual arm single furnace thermo-analyzer as a transpiration apparatus gave a value of 51.3 ± 1.9 kJ mol −1 for the enthalpy of sublimation ( Δ sub H°) for TMSS in the temperature range of 315.93–416.49 K. The non-isothermal sublimation kinetic reaction mechanism predicted by the Coats–Redfern (CR) model-fitting analysis was 2D diffusion (D2-Valensi equation) and phase boundary (contracting area) controlled and also it was confirmed from the full width of DTG peaks (shape method) suggested by Dollimore. The demonstration of SiC thin film deposition was carried out using plasma-assisted liquid injection chemical vapor deposition (PA-LICVD) and films were analyzed using SEM/EDX techniques.

Experimental validation of dual/modified dual arm locking for LISA

The laser frequency stabilization subsystem is one of the most significant parts within the interferometric measurement system of LISA. Arm locking as a proposed frequency stabilization technique synthesizes an adequately filtered linear combination of the interferometry signals as a frequency reference. Until now all the benchtop experiments on arm locking verified only the basic single arm locking configuration with unrealistic short signal travel times. At the University of Florida we developed the hardware-based University of Florida LISA Interferometer Simulator (UFLIS) to study and verify laser frequency noise reduction and suppression techniques under realistic LISA-like conditions. These conditions include the Doppler shifts between the spacecraft, LISA-like signal travel times, realistic laser frequency and timing noise. In this paper we will report about preliminary experiments on advanced arm locking schemes including dual arm locking and modified dual arm locking with realistic 33 s light travel times. In our experiments the implementation of a dual/modified dual arm locking sensor and controller is realized using several digital signal processing boards. We demonstrated the closed-loop stability of arm locking setup and measured the noise suppression in these experiments.

Robotic virtual manipulations of a nuclear hot‐cell digital mock‐up system

PurposeHot‐cells are shielded structures protecting individuals from radioactive materials. The purpose of this paper is to propose a design approach for a hot‐cell simulator using digital mock‐up (DMU) technology and combining Haptic guided complex robotic manipulation for assembly tasks in a virtual environment.Design/methodology/approachThe principal reason for developing a simulator was to explore the feasibility of hot‐cell structure design and collision‐free assembly process. For this, a simulation design philosophy has been proposed that includes DMU facility offering the ability of analyzing the operations and performing complex robotic manipulations in the virtual hot‐cell environment. Furthermore, enhanced Haptic mapping for tele‐manipulation is proposed for training and guidance purposes.FindingsFrom the analysis and task scenarios performed in virtual simulator, the optimal positions of the manipulators and need of (bridge transport dual arm servo‐manipulators) type were identified. Operation tasks were performed remotely using virtual hot‐cell technology by simulating the scenarios in the DMU reducing the overall operation cost and user training. The graphic simulator substantially reduced the cost of the process and maintenance procedure as well as the process equipment by providing a pre‐analysis of whole scenario for real manipulation.Originality/valueThis research tries to contribute to the virtual hot‐cell design philosophy. Tele‐operated complex robotic operations in DMU technology are performed in virtual hot‐cell. The simulator provides improved Haptic guidance with force and torque feedback enhancing the realism of virtual environment.

Destruction Avoidance for Dual Arm Construction Machinery Using Mechanical Impedance Adjustable Hydraulic Circuit

Dual arm work machine that consists of hydraulic excavator is expected for transportation of long objects such as steel stocks and destruction of concrete walls by cooperating dual arm. However, cooperation of two or more arms generates overload in a work object and arms. Because the arms form closed-loop through the work object, refuge of internal force disappears. In this paper, a nondestructive dual manipulation technique for reducing working load is designed using indirect force control that applies in a part of one arm. Operator's positioning accuracy in transportation of long object is measured by a front structure of the hydraulic excavator. From the results, permissible positioning error in nondestructive dual manipulation is clarified. Moreover, load of working object is reduced by indirect force control by using hydraulic circuit with accumulator. Target mechanical impedance is maintained by combining hydraulic circuit with adaptive control in hydraulic system that changes the load characteristic while working. Transportation work experiment of long object is conducted by using the lifter that corresponds to positioning control manipulator and the hydraulic excavator that applies the force control system. Working load has decreased to 20% of maximum working load of the front structure of the construction machinery. Usable range of nondestructive manipulation is clarified by a chart that shows relations between expected load decrease and target mechanical impedance characteristic decided with the work object. Therefore, nondestructive dual arm manipulation of the construction machinery can be achieved by using the mechanical impedance adjustment with combination of the hydraulic circuit and the adaptive control.

1A1-E05 6-DOF Target Posture of Small Objects for Grasping Task by 7-DOF Dual Arm Robot(Robots for Works)

Capability to manipulate small objects is an important requirement in designing assembly robot. Majority of related studies use one or dual arm robot with gripper or fingered hands for their end effectors. The manipulated objects are usually from common household and not suitable to attend smaller size of object. Therefore, we proposed our robot that consists of a seven-link dual-arm manipulators and three-fingered hands for cooperative tasks involving small objects. As an initial work, we calculate the 6-DOF posture of featureless, small and unobvious color of a hexagonal M10 nut (diameter, 19.6mm). We propose a technique called Confirm-Estimate-Rotate (CER) that employs image processing techniques to integrate with the robot algorithm for a grasping task. Real-time experiment results proved the capability of our method for the manipulation on small objects. It successfully made the multi-link robot change its posture safely to match the target posture in unstructured conditions.

Dual arm robot for flexible and cooperative assembly

Dual-arm robots provide efficient approach for automated execution of complex assembly operations. With bimanual-manipulation, a dual-arm robot can simultaneously control relative motion and interaction of assembly counterparts in a dexterous human-like manner. This requires, however, sophisticated programming and control algorithms for arms cooperation. This paper addresses the development of an advanced industrial dual-arm robot system with novel capabilities, such as easy and rapid commissioning, compliance control of bimanual interaction in all assembly process phases, as well as intuitive planning and programming. The robot can be leased and easily integrated in assembly environment sharing the same workspace with human workers.

양팔 로봇의 협조제어를 위한 최적 경로 설계

This paper proposes a cooperative control algorithm for a dual-arms robot which is carrying an object to the desired location. When the dual-arms robot is carrying an object from the start to the goal point, the optimal path in terms of safety, energy, and time needs to be selected among the numerous possible paths. In order to quantify the carrying efficiency of dual-arms, DAMM (Dual Arm Manipulability Measure) has been defined and applied for the decision of the optimal path. The DAMM is defined as the intersection of the manipulability ellipsoids of the dual-arms, while the manipulability measure indicates a relationship between the joint velocity and the Cartesian velocity for each arm. The cost function for achieving the optimal path is defined as the summation of the distance to the goal and inverse of this DAMM, which aims to generate the efficient motion to the goal. It is confirmed that the optimal path planning keeps higher manipulability through the short distance path by using computer simulation. To show the effectiveness of this cooperative control algorithm experimentally, a 5-DOF dual-arm robot with distributed controllers for synchronization control has been developed and used for the experiments.

A Framework to Identify Task-Phase and Attentional-Condition for Supporting Complicated Dual-Arm Operations

The state identification framework we propose supports complex construction machinery operations using a dual arm. Such support requires compatibility with different types of support and commonality among various operator skill levels. Our framework is organized into (i) real-time task phase identification defined using joint load applied based on environment constraints and (ii) time-series attentional condition identification defined as an internal work-state condition classified by the operational support necessity level and dependent on the vectorial or time-series data selected by the identified task phase. Experiments are conducted using the instrumented hydraulic dual arm system for transport and removal tasks, including complex dual-arm operations. Results show that the number of erroneous contacts, internal force applied, and mental workload decreased without any increase in time, confirming that operational support based on our framework greatly improves individual operator work performance.

Load transportation by dual arm robot using sliding mode control

In this study, a sliding mode controlled dual arm robotic system was designed. Such multi-arm, collaborative and synchronous robots typically are employed in hazardous situations such as radioactive materials transport explosives disposal and industrial applications. In the present study, a high performance, robust, non-chattering sliding mode controller (SMC) was developed for the purpose of safe load handling, transportation and trajectory realization. First, dynamic equations of robot/load interaction were derived. Then, the robust SMC was designed for the dual arm robotic system. In order to test the robustness of the proposed SMC, parameter variations and external disturbances were introduced to the system. Furthermore, for comparative purposes, the conventional and widely used, PID controller was also applied to the dual arm robot. Significantly, it was found that the SMC made smaller trajectory tracking errors than the PID controller. An overall analysis of the numerical results confirmed that the dual-arm robotic systems with the proposed SMC can safely and effectively be used in hazardous applications.

A high-dexterity low-degree-of-freedom hybrid manipulator structure for robotic lion dance

Lion dance is a very popular and lively Chinese traditional art form. A robotic project in Singapore has been dedicated to the design and demonstration for similar traditional art forms using modern mechatronics technology. This paper deals with a novel six-degree-of-freedom (6-DOF) hybrid manipulator with high stiffness, high loading capability and high dexterity, mimicking the lion dancer’s upper body motions along with the lion head movements. The design of the hybrid manipulator consists of a 2-DOF torso structure in serial configuration and a 4-DOF dual arm structure in parallel configuration. The combined 6-DOF hybrid manipulator can support the weight and dynamics of the lion head during the lion dance performance. Forward kinematics of the manipulator has been formulated and visualized for design purposes. Inverse kinematics of the hybrid manipulator were analytically derived for real-time motion control. Based on the design and modeling, a complete hybrid manipulator has been fabricated, implemented into the robotic lion, and successfully demonstrated for real robotic lion dance performance.

Notes Omental Patch Repair of Gastric Perforation Is Comparable to Laparoscopic Repair in a Porcine Model

Background: Perforation accounts for over 70% of deaths associated with peptic ulcer disease. Post-interventional complications contribute to short-term patient outcome. Reduction of procedural impact may decrease morbidity and mortality. A natural orifice translumenal approach may decrease surgical physiologic impact. Hypothesis: NOTES omental patch repair of full thickness gastrotomy is feasible with decreased physiologic impact compared to laparoscopy. Design: Randomized, dual arm, porcine 2-week survival trial. Setting: IACUC approved study with 28 swine. Methods: Twenty-eight swine were randomized to laparoscopic (n=14) or NOTES repair (n=14) of a 1 cm anterior wall gastrotomy. Gastrotomy was created laparoscopically followed by four hours wait (soilage) time. After peritoneal cavity irrigation, repair proceeded with laparoscopic omental patch (Lap) or NOTES approach. For NOTES repair, an endoscope was advanced into the stomach and through the perforation. Omentum was grasped with endoscopic biopsy forceps, pulled into the gastric lumen, and fixed with metallic clips. Procedure and clinical parameters including necropsy were recorded. Serum samples were collected for WBC count and TNF-α analysis using dual-sandwich ELISA. T -test, Wilcoxon Rank sum test, and Levene's test were used for statistical analysis Results: NOTES repair failed in one animal (unable to exit perforation); this was repaired laparoscopically, data were analyzed as intention to treat. Twenty-four of 28 animals thrived to study completion. Two NOTES, 1 Lap swine succumbed to airway compromise in recovery; 1 NOTES animal failed to thrive on POD 7. No intra-abdominal cause for these deaths was found. At necropsy, all repairs were intact. Mean NOTES repair time was comparable to laparoscopy (NOTES: 28 min vs. Lap: 33 min, p=0.5). WBC counts from both groups were comparable on POD 1 (NOTES: 18.1 vs. Lap: 17.5, p=0.44). Mean TNF-α serum levels in the NOTES group on POD1 were not significantly different from laparoscopy (NOTES: 25.3 pg/nL vs. Lap: 51.5 pg/nL, p=0.12); a significant difference in TNF-α variation from baseline at procedure conclusion (p<0.01) and POD 1(p=0.044) was noted between NOTES and Lap animals. Conclusion: Endoscopic perforated hollow viscus repair was technically feasible in this experimental model and may be slightly less invasive. Early results appear encouraging and warrant further evaluation.

Lopinavir/ritonavir + tenofovir Dual Therapy versus Lopinavir/ritonavir-Based Triple Therapy in HIV-Infected Antiretroviral Naïve Subjects: The Kalead Study

Purpose: With reference to the clinical need for simple, potent and safe antiretroviral regimens, Lopinavir/ ritonavir + tenofovir (LPV/r+TDF) two-drug initial regimen was studied for efficacy and safety in HIV-infected patients. Methods: Kalead was a prospective, randomized, open-label, 72-week trial comparing LPV/r+TDF versus LPV/r+ two (non-TDF) NRTIs in HIV-infected adults with HIV-RNA >400 copies/mL and any CD4 count. Primary endpoint was the proportion of subjects with HIV-RNA <50 copies/mL at week 72. Results: 152 subjects were randomized. Eleven (15.3%) subjects in the dual therapy arm and seven (8.8%) in the triple therapy arm who did not achieve HIV-RNA <50 copies/mL at least twice prior to and including week 24 were discontinued per protocol (p=0.21). Overall discontinuations were 41.7% and 43.8% in the dual therapy and triple therapyarms. At week 72, 51.4% and 52.5% of subjects in the dual therapy and triple therapy arms had HIV-RNA <50 copies/mL (p=0.89, ITT, NC=F). In an on-treatment analysis, 87.2% and 93.0% of subjects in the dual therapy and triple therapy arms had a HIV-RNA <50 copies/mL (p=0.47). Over 72 weeks of therapy, mean CD4 count increases were greater in the dual therapy arm (+332 cells/mm3 vs +234 cells/mm3, p=0.01). Adherence, overall incidence of adverse events, drugrelated adverse events, and Grade I-IV laboratory abnormalities were comparable between the two arms. Conclusions: A two-drug regimen of LPV/r+TDF suggests sufficient safety and efficacy warranting further investigation. However, high discontinuation rate and study design limitations restrict overall interpretation.

2B34 Dexterous Manipulation for Assembly Work Using Multilink Dual Arm Manipulator with Vision Sensors

This paper presents our work on realizing the manipulation of nut and bolt for assembly work using dual arm manipulator. The robot architecture consists of multiple active sensors and control procedures that are structured to work for real time operations. It is specifically designed to be similar to human arm which has seven joints for each arm to perform complicated assembly tasks on small parts using both hands that usually requires high cost human labour. Sensors are optimally used to provide data of the environment and the target object in variable conditions, shapes and sizes. Data between eye-in-hand and eye-to-hand cameras are fused and handled together with force sensors and encoders to calculate the required robot dynamics of the seven link arms for object manipulation. The first experiment that has been used as the basic platform in preparing our robot for assembly task consists of autonomous picking and placing an M8 sized bolt and hexagonal nuts of minimum 2 mm radius. Besides, based on the proposed vision processing, the robot hand could self adjust its wrist angle to avoid collision between the fingers and objects during grasping. Moreover, we showed application of vision to align M10 bolt and nut for complicated screwing operation. Experiment results are laid out to show the robot performance for above operations thus producing a dexterous dual arm robot for assembly work purposes.

1P1-D26 水中ロボットマニピュレータの動作時における浮心移動機構を利用した本体姿勢補償

We have developed an attitude compensation system for a human-sized remotely operated vehicle (ROV) with dual arm based on shifting the center of buoyancy with respect to the center of gravity. Shifting of the center of buoyancy is accomplished by movable float blocks. In this paper, we enhance the dynamic motion performance of the attitude compensation system. Through several experiments, we investigate that this system is able to maintain the pitch angle of the ROV during motion of the manipulators.

Compact wideband balanced antenna for mobile handsets

A novel miniature balanced mobile handset antenna is presented in this study, which covers digital communication system (DCS) (1710–1880 MHz), personal communication system (PCS) (1850–1990 MHz), universal mobile telecommunications system (UMTS) (1920–2170 MHz) and wireless local area network (WLAN) (2400–2484 MHz) frequency bands. The antenna is a built-in planar dipole with folded structure and with the addition of a dual arm on each half of the dipole. The performance of the antenna is analysed and optimised under certain design constraints. The stability performance of the proposed antenna against proximity effects is evaluated. The effects of the phone user's hand on the return loss and radiation patterns have been characterised by simulation with a simple hand model. A prototype of the proposed antenna is fabricated and tested. A wide bandwidth planar balun is used to feed the wideband balanced antenna from an unbalanced source. The calculated and measured results show good agreement and confirm good wideband characteristics with multiband operation. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring near field exposure. The measured results have shown low induced current in the ground plane and thus confirm minimisation of performance variations and SAR.