This paper considers the problem of attitude synchronization for a group of flexible spacecraft based on distributed attitude cooperative control strategy. Based on the backstepping design, non-smooth control, and the...
This paper considers the problem of attitude synchronization for a group of flexible spacecraft based on distributed attitude cooperative control strategy. Based on the backstepping design, non-smooth control, and the neighbor-based design rule, a distributed attitude control law is constructed step by step. Under the proposed control law, it is shown that the attitude synchronization is achieved asymptotically and the induced vibration by flexible appendages is simultaneously suppressed.
In this paper a nonlinear attitude tracking control scheme is developed for a small-scaled unmanned helicopter under input constraints. Via the analysis of the properties associated with the helicopter's rotor dyn...
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ISBN:
(纸本)9781479932757
In this paper a nonlinear attitude tracking control scheme is developed for a small-scaled unmanned helicopter under input constraints. Via the analysis of the properties associated with the helicopter's rotor dynamics, the elevator servo input, the aileron servo input, and the rudder servo input are chosen to be the control inputs to be designed. Their constraints in amplitude under hovering flight is taken into account by using the robust bounded terms in the controller design. The asymptotic convergence of the tracking error is guaranteed with the Lyapunov-based stability analysis.
In this paper, the problem for the control of a class of single-input-single-output (SISO) non-affine nonlinear system with non-varnishing disturbance is investigated. A continuous nonlinear feedback structure is util...
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ISBN:
(纸本)9781479932757
In this paper, the problem for the control of a class of single-input-single-output (SISO) non-affine nonlinear system with non-varnishing disturbance is investigated. A continuous nonlinear feedback structure is utilized to tackle with the uncertain dynamics in the system. By taking the time derivative of the origin system, a transformed affine-like form is derived. The first order derivative of control input appears linearly in the augmented dynamics with unknown control direction. Nussbaum-type function is incorporated to estimate the unknown control direction. A revised Lyapunov based analysis is carried out to prove that under some moderate assumptions, the Semi-global Uniformly Ultimately Bounded (SGUUB) tracking result is achieved and all the closed loop signals are bounded. Numerical simulation results are presented to illustrate the performance of the proposed control law.
The pseudo transient-analysis method is regarded as one of the most effective method to find DC operating points for nonlinear circuits. In this paper, we combine the ramping method and the damped pseudo-transient ana...
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The pseudo transient-analysis method is regarded as one of the most effective method to find DC operating points for nonlinear circuits. In this paper, we combine the ramping method and the damped pseudo-transient analysis algorithm together in order to improve the simulation efficiency. By combing the two algorithms together, the oscillation problem and time-consuming problems can be greatly eliminated. Numerical examples are shown to demonstrate the efficiency of proposed algorithms.
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.
This paper focuses on the problem of secure distributed consensus to defend covert misbehavior in wireless sensor networks (WSNs). Distributed consensus is a promising method to improve the efficiency and precision of...
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This paper focuses on the problem of secure distributed consensus to defend covert misbehavior in wireless sensor networks (WSNs). Distributed consensus is a promising method to improve the efficiency and precision of consensus results in WSNs, but it introduces new security issues that malicious nodes may manipulate false sensing data to degrade the sensing result of the whole network. A data falsification attack, i.e., the attacker injects random values into its neighboring nodes at each time-step of consensus process, is considered. This kind of attack cannot be defended against by most of existing detection mechanisms. We present a distributed detection mechanism with adaptive local threshold to isolate the abnormal nodes. A Weighted Averaging-based Consensus Scheme (WACS) is proposed to decrease the negative impact of the attack and make the network converge to a consensus value. It is proved that convergence property can be guaranteed by the relationship between weighted average of the noise and stochastic approximation. Simulation results are presented to show the effectiveness of the proposed secure scheme.
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.
Stable walking of bipedal humanoid is an crucial and challenge issue of research in bipedal robots. And the structure of shoe sole plays a significant role in preventing someone from slipping in human life. The humano...
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ISBN:
(纸本)9781479973989
Stable walking of bipedal humanoid is an crucial and challenge issue of research in bipedal robots. And the structure of shoe sole plays a significant role in preventing someone from slipping in human life. The humanoid robot foot often skid while the robot is walking fast, and it may cause serious harmfulness. This study presents some foot pads for humanoid robot to improve its stability and reliability. First, anti-skid foot for a humanoid robot is proposed in this paper. Second, the material and pattern of foot pads are selected. Finally, the better foot pads are chosen by several experiments and the effectiveness of the new foot pads is confirmed by comparison experiments.
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.
Finite-time controlsystems usually have better disturbance rejection property and faster convergence performance. For the linearized dynamics of the linear navigation system of an agricultural tractor, a novel contro...
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