Fabrication and assembly of highly articulating structures has been a challenge for manufacturing engineers for several years. This challenge is further enhanced when the structures are in the miniature size scales. A...
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ISBN:
(纸本)9781622762477
Fabrication and assembly of highly articulating structures has been a challenge for manufacturing engineers for several years. This challenge is further enhanced when the structures are in the miniature size scales. As part of our previous work, we have developed a process called in-mold assembly to tackle this challenging manufacturing and assembly task. However, attaching the actuators to such miniature structures remains a challenging task and can be expensive in terms of costs. In this work, we will demonstrate a single step in-mold assembly method to fabricate miniature multi degree of freedom (DOF) mechanical devices with embedded SMA actuators. We have developed design optimization methods to shield the SMA actuators from the thermal cycles seen during the injection molding process. This is done to minimize thermal impact on the SMA actuators during embedding in in-mold assembled articulating joints. We have also developed experimental methods to calibrate the force and position of the embedded SMA actuators with respect to temperature. Our experimental results indicate that the SMA behavior is very repeatable with respect to temperature. Hence temperature can be used as a sensory feedback for position and force control. Using the approaches developed as part of this work, we have successfully fabricated an in-mold assembled multi DOF miniature robot with embedded SMA actuators.
This paper presents a study on the Design Of Experiments (DOE)-based parameter optimization technique to adapt to the manufacturing environment changes in robotic force control assembly. Based on a real-world transmis...
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This paper presents a study on the Design Of Experiments (DOE)-based parameter optimization technique to adapt to the manufacturing environment changes in robotic force control assembly. Based on a real-world transmission torque converter assembly production process, investigation and analysis are performed in production. An on-pendant robotic assembly parameter optimization tool is introduced. When manufacturing environment changes such as the changes of geometrical dimension of part and tool (the location of feature on part, the size of the feature, the dimension of the tool, etc.), the changes of position and orientation of part, fixture or robot;the changes of properties of part (weight, spring constant, etc.), the performance metrics such as mean of the cycle time, mean plus 3 sigma of the cycle time, first time through (FTT) rate are degraded. The on-pendant optimization tool applies full factorial experiments on the most influential parameters. Then the results are subjected to statistical analysis to find the optimal parameter set. Finally verifying the optimized parameter set through running a number of experiments and checking on performance of the force control assembly to adapt the changes. The efficiency of proposed method is proved in the Ford Powertrain assembly production. The program continues running in production and adjusting the process parameters to adapt the manufacturing variations. The real factory acceptance testing results are presented and analyzed. Finally, conclusions are drawn and discussion and further investigation is proposed.
We propose a vision-based position control method, with the purpose of providing some level of autonomy to a quad-rotor unmanned aerial vehicle. Our approach estimates the helicopter X-Y-Z position with respect to a l...
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We present a vision system that deals with the problem of local estimation of the position and velocity of a UAV quad-rotor indoor. Our approach is based in the estimation of homographies from a visual landmark. Stabi...
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ISBN:
(纸本)9783902661968
We present a vision system that deals with the problem of local estimation of the position and velocity of a UAV quad-rotor indoor. Our approach is based in the estimation of homographies from a visual landmark. Stabilizing the UAV locally, real time experiments demonstrate the effectiveness of our method.
In this paper, the meshing theory of the angle modified hourglass worm drive is enriched and developed. The ordinary condition of the angle modification is derived and the physical significance of the modification is ...
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In this paper, the meshing theory of the angle modified hourglass worm drive is enriched and developed. The ordinary condition of the angle modification is derived and the physical significance of the modification is interpreted. A normal section methodology is proposed for meshing analysis, which can be used to compute the normal distance near a singular meshing point of a conjugate surface couple. By means of the method and after analyzing the normal transversals, it is specified that the worm helicoid, the nominal former contact zone and the new contact zone intersect each other along the locus of singular points of the instantaneous contact lines of an angle-modified worm pair. As a result, it is explained clearly that those three osculate each other but the osculations are different in degree. Moreover, the mechanism of removing the twice-contacted zone from the worm gear tooth surface is clarified and the reason of shortening the worm working length is also elucidated. With the help of the theory described in the present paper and the thorough and systematic research on the relevant meshing characteristics, the angle modified dual tori double-enveloping toroidal worm drive has been shown to be an excellent new-fashioned hourglass worm set.
Abstract AbstractWe present a vision system that deals with the problem of local estimation of the position and velocity of a UAV quad-rotor indoor. Our approach is based in the estimation of homographies from a visua...
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Abstract AbstractWe present a vision system that deals with the problem of local estimation of the position and velocity of a UAV quad-rotor indoor. Our approach is based in the estimation of homographies from a visual landmark. Stabilizing the UAV locally, real time experiments demonstrate the effectiveness of our method.
Consensus strategies find extensive applications in coordination of robot groups and decision making of agents. Since balanced graph plays an important role in the average consensus problem for directed communication ...
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Consensus strategies find extensive applications in coordination of robot groups and decision making of agents. Since balanced graph plays an important role in the average consensus problem for directed communication networks, this work explores the conditions and algorithms for the digraph balancing problem. It has been proved that a directed graph can be balanced if and only if the null space of its incidence matrix contains positive vectors. Then two weight balance algorithms have been proposed, and the conditions for obtaining a unique balanced solution have been investigated. This work has also pointed out the relationship between the weight balance problem and the features of the corresponding underlying Markov chain. Finally, two numerical examples are presented to verify the proposed algorithms.
This paper analyzes the craft of vacuum casting and proposes modularized frame of a new automated vacuum casting controlling system which is integrated by four sub-modules that are main-control module, electric contro...
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The localized management of sinus floor (LMSF) is one of key technologies in dental implant surgery, but the lining mucosa of maxillary sinus is easily impaled during LMSF surgery. This paper proposed a computer aided...
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The localized management of sinus floor (LMSF) is one of key technologies in dental implant surgery, but the lining mucosa of maxillary sinus is easily impaled during LMSF surgery. This paper proposed a computer aided design method to construct 3-D finite element model of LMSF. Then the models are processed for analysis. Finally, the virtual surgery simulation was carried out from three aspects which include distance between the apex of bone condenser friadent and the maxillary sinus floor, the shape of maxillary sinus floor and the position of bone condenser friadent. The obtained conclusions can give dentists some directions to carry out clinical LMSF operations. Thus the surgical process can be better planned by dentists, so the success rate of operation also can be improved. In summary, the virtual LMSF surgery simulation has positive significance for both dentists and patients and this method can be applied in various kinds of surgeries to help clinical doctors plan the process of operations.
This paper presents the objective metric study on design of experiments (DOE)-based robotic force control parameter optimization in transmission torque converter assembly. Based on a real-world assembly production pro...
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This paper presents the objective metric study on design of experiments (DOE)-based robotic force control parameter optimization in transmission torque converter assembly. Based on a real-world assembly production process, investigation and analysis are performed on the optimization metrics of assembly cycle time mean (MEAN), its mean plus three times of standard deviation (MEAN+3*STDEV), and first time through (FTT) rate. Simulations have been conducted to illustrate and explain the findings in the parameter optimization practice. Practical metric criteria have been proposed and discussed. An on-pendant robotic assembly parameter optimization tool with the objective metric concept is introduced. And automatic parameter optimization or online robot learning feature is also mentioned in terms of the objective metrics for the particular robot assembly parameter optimization tasks. Finally conclusions are drawn and discussion and further investigation is proposed.
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