A series of single hole devices are designed based on the different concentrations of FeCl3 doped in 4, 4'-Bis(9H-carbazol-9-yl)biphenyl (CBP). The hole mobilities of p-type doped CBP by FeCl3 with various doping ...
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A series of single hole devices are designed based on the different concentrations of FeCl3 doped in 4, 4'-Bis(9H-carbazol-9-yl)biphenyl (CBP). The hole mobilities of p-type doped CBP by FeCl3 with various doping concentrations are estimated by using space-charge-limited current model, and compared with the mobility of NPB which is a kind of hole transport material commonly used in organic electroluminescence devices. The results indicate that FeCl3 doped CBP has significantly improved hole mobility. The highest hole mobility is achieved when the concentration of FeCl3 is 12%. For an electric field of 0.5 MV/cm, the estimated hole mobility of FeCl3-doped CBP with doping concentration of 12% reaches 4.5×10-5 cm2/V · s. Even in zero electric field, the hole mobility can reach 2.2×10-5 cm2/V · s, which is nearly four times of that of NPB. High efficiency organic light-emitting device is fabricated by using CBP: 12% FeCl3 as the hole transport layer. The device shows a maximum luminance of 68468 cd/m2 and a maximum current efficiency of 31.1 cd/A, which are increased by 97% and 23% compared with those of the reference device, respectively. The improvements are attributed to the balanced charge carrier transport characteristic, which results in an increased charge carrier recombination probability and a decreased triplet-polaron (T-P) annihilation probability.
With applying the information technology to the military field, the advantages and importance of the networked combat are more and more obvious. In order to make full use of limited battlefield resources and maximally...
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With applying the information technology to the military field, the advantages and importance of the networked combat are more and more obvious. In order to make full use of limited battlefield resources and maximally destroy enemy targets from arbitrary angle in a limited time, the research on firepower nodes dynamic deployment becomes a key problem of command and control. Considering a variety of tactical indexes and actual constraints in air defense, a mathematical model is formulated to minimize the enemy target penetration probability. Based on characteristics of the mathematical model and demands of the deployment problems, an assistance-based algorithm is put forward which combines the artificial potential field (APF) method with a memetic algorithm. The APF method is employed to solve the constraint handling problem and generate feasible solutions. The constrained optimization problem transforms into an optimization problem of APF parameters adjustment, and the dimension of the problem is reduced greatly. The dynamic deployment is accomplished by generation and refinement of feasible solutions. The simulation results show that the proposed algorithm is effective and feasible in dynamic situation.
A humanoid robot may suffer from slip since its two feet are not fixed on the ground. Slip occurrence may induce the loss of robot's balance. The previous literature focused on the detection or estimation of the s...
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A humanoid robot may suffer from slip since its two feet are not fixed on the ground. Slip occurrence may induce the loss of robot's balance. The previous literature focused on the detection or estimation of the slip occurrence, or only employed the translational acceleration regulation to overcome slip. This study proposes a slip prevention method by coordinating acceleration vector including the horizontal, vertical, and rotational acceleration components. The contribution of this paper is to regulate the translational and rotational acceleration together to prevent the slip occurrence. The effectiveness of our proposed method was verified by simulations and experiments on an actual humanoid robot.
This paper presents a control strategy based on phase modification during double support period to enhance a humanoid robot's walking stability. When the foot of the swing leg touches the ground, if Zero Moment Po...
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ISBN:
(纸本)9781479973989
This paper presents a control strategy based on phase modification during double support period to enhance a humanoid robot's walking stability. When the foot of the swing leg touches the ground, if Zero Moment Point(ZMP) is not in the stable margin, the phase modification will start. According to the position of ZMP and the relationship between the motion of Center of Gravity(COG) and ZMP position, the related parameters are solved. Series of experiments are taken, and the effectiveness of the method is validated repeatedly.
A kind of four degree-of-freedom (DOF) electrohydraulic lift system is studied in this pa- per, after analyzing the motion characteristics and the mathematic model of the hydraulic cylinders, a cross-coupled synchro...
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A kind of four degree-of-freedom (DOF) electrohydraulic lift system is studied in this pa- per, after analyzing the motion characteristics and the mathematic model of the hydraulic cylinders, a cross-coupled synchronization method with load force and synchronization error feedback had been proposed to solve the synchronization problem encountered when realizing the needed roll and pitch attitude of the lift system. In this paper, mathematic model of asymmetric hydraulic cylinder was es- tablished and the lift system had been simplified to a dual-cylinder system. By incorporating the load force and the displacement of each cylinder, a cross-coupled synchronized control method was pro- posed to fit each cylinder' s tracking performance and multi-cylinder' s trajectory synchronization property. The proposed method not only solved the synchronization problem when multi-cylinder had a same trajectory, but also could fit the coordinated synchronization need when different trajectories of multi-cylinder were desired. Simulations and experiments on a four DOF electrohydraulic lift sys- tem with load of 100 tons verified the effectiveness of the proposed method.
In hierarchical electricity market, the retailers buy electricity from generation provider and then sell it to users. Retailers play an important role in the distribution channel by matching supply and demand, but the...
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ISBN:
(纸本)9781479937097
In hierarchical electricity market, the retailers buy electricity from generation provider and then sell it to users. Retailers play an important role in the distribution channel by matching supply and demand, but they also potentially cause inefficiencies in electricity allocation. To induce an efficient allocation of electricity, we propose a novel hierarchical distributed method under PSP auction mechanism. Under this mechanism, each of players, either the generation provider or the retailers, obtains their electricity allocation through the PSP auction method by submitting a multi-dimensional bid profile, instead of telling their private cost or valuation function, then the retailers economically distribute the electricity, acquired in the PSP auction, among users. Moreover, the valuation function of retailers depends on the revenues that they sell the electricity to users. As a main result, in this paper we show that there exists an efficient Nash equilibrium (NE) for the underlying auction games.
For biped robot, friendly environment interaction makes sense. In this paper, a new method to plan the gait and control a biped robot on stairs with desired ZMP is proposed first. The desired ZMP derived from an itera...
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For biped robot, friendly environment interaction makes sense. In this paper, a new method to plan the gait and control a biped robot on stairs with desired ZMP is proposed first. The desired ZMP derived from an iterative optimal algorithm not only has enough stability margin and satisfies actuator specifications, but also is available to implement and energy saving. Then, a controller with force sensing and variable impedance is proposed, which can sense and compensate the environmental disturbance well. Finally, the effectiveness of the proposed methods is confirmed by simulation examples.
作者:
Li, JiaojieZhang, WeiSu, HoushengYang, YupuDepartment of Automation
Shanghai Jiao Tong University and Key Laboratory of System Control and Information Processing Ministry of Education of China Shanghai China Department of Measurement and Control Technology
Shanghai Dian Ji University Shanghai China School of Automation
Key Laboratory of Image Information Processing and Intelligent Control (Huazhong University of Science and Technology) Ministry of Education National Key Laboratory of Science and Technology on Multispectral Information Processing Huazhong University of Science and Technology Wuhan China
In this paper, we study the flocking problem of multi-agent systems with obstacle avoidance, in the situation when only a fraction of the agents have information on the obstacles. Obstacles of arbitrary shape are allo...
In this paper, we study the flocking problem of multi-agent systems with obstacle avoidance, in the situation when only a fraction of the agents have information on the obstacles. Obstacles of arbitrary shape are allowed, no matter if their boundary is smooth or non-smooth, and no matter it they are convex or non-convex. A novel geometry representation rule is proposed to transfer obstacles to a dense obstacle-agents lattice structure. Non-convex regions of the obstacles are detected and supplemented using a geometric rule. The uninformed agents can detect a section of the obstacles boundary using only a range position sensor. We prove that with the proposed protocol, uninformed agents which maintain a joint path with any informed agent can avoid obstacles that move uniformly and assemble around a point along with the informed agents. Eventually all the assembled agents reach consensus on their velocity. In the entire flocking process, no distinct pair of agents collide with each other, nor collide with obstacles. The assembled agents are guaranteed not to be lost in any non-convex region of the obstacles within a distance constraint. Numerical simulations demonstrate the flocking algorithm with obstacle avoidance both in 2D and 3D space. The situation when every agent is informed is considered as a special case.
In order to solve the linear variable differential transformer (LVDT) displacement sensor nonlinearity of overall range and extend its working range, a novel line-element based adaptively seg- menting method for pie...
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In order to solve the linear variable differential transformer (LVDT) displacement sensor nonlinearity of overall range and extend its working range, a novel line-element based adaptively seg- menting method for piecewise compensating correction was proposed. According to the mechanical structure of LVDT, the output equation was calculated, and then the theoretic nonlinear source of output was analyzed. By the proposed line-element adaptive segmentation method, the nonlinear output of LVDT was divided into linear and nonlinear regions with a given threshold. Then the com- pensating correction function was designed for nonlinear parts employing polynomial regression tech- nique. The simulation of LVDT validates the feasibility of proposed scheme, and the results of cali- bration and testing experiments fully prove that the proposed method has higher accuracy than the state-of-art correction algorithms.
Both disturbance rejection and human-like motions, like toe-off and heel-strike, are important for a biped robot to enhance its performance. However, the required motions for them may influence each other, which is wh...
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ISBN:
(纸本)9781479971756
Both disturbance rejection and human-like motions, like toe-off and heel-strike, are important for a biped robot to enhance its performance. However, the required motions for them may influence each other, which is why few studies consider them simultaneously. This paper presents a method to realize stable walking with toe-off and heel-strike even when the robot experiences disturbances. We propose a walking controller which can constrain the desired ground reaction force. On the one hand, the controller can adjust the torso acceleration to make the supporting leg compliant with the external disturbances on the torso. On the other hand, it can rotate the supporting foot by adjusting the ZMP to an appropriate location. The linear inverted pendulum is utilized to generate the CoM trajectory and the foot placement. Meanwhile, its ZMP can be predefined as required so that the toe-off and heel-strike can be achieved by the controller. The effectiveness of the proposed method is demonstrated by simulations.
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