In this paper, robust attitude coordination control for satellite formation is addressed in the presence of matched perturbations and measurement noise based on the development of reference model. The reference model ...
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ISBN:
(纸本)9781479932757
In this paper, robust attitude coordination control for satellite formation is addressed in the presence of matched perturbations and measurement noise based on the development of reference model. The reference model generates a smooth and coordinated attitude reference trajectory(ART) for each satellite, which is favorable for the design of attitude tracking and formation keeping control law. The sliding mode control is applied such that the satellite formation controller is global robust against matched perturbations. To attenuate the influence of measurement noise on formation-keeping(i.e., H_∞-type performance), linear matrix inequality(LMI) method is used to design sliding-mode parameters. Finally, a numerical example is introduced to illustrate the efficiency of the proposed method.
Terrain perception in complex environment is important for Autonomous Land Vehicle to drive automatically. In order to access the terrain information, in this paper, we present a terrain perception method based on Hid...
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Terrain perception in complex environment is important for Autonomous Land Vehicle to drive automatically. In order to access the terrain information, in this paper, we present a terrain perception method based on Hidden Markov Model (HMM) which combines LIDAR with machine vision. On the basis of spatial fan-shaped model, terrain feature extraction is performed to acquire the observation model. Hidden markov models describe the vertical structure of the driving space and Viterbi algorithm is used for terrain classification. Then the navigation decision is given based on the perception of the complex environment. Experiment results show that the method can give an accurate environment description for ALV.
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 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.
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.
Based on the excellent mechanical structure of the wheel-foot multi-joint mobile robot, we have strictly deduced the direct and inverse kinematical formulas of the robot's legs. So the theoretical method and techn...
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Based on the excellent mechanical structure of the wheel-foot multi-joint mobile robot, we have strictly deduced the direct and inverse kinematical formulas of the robot's legs. So the theoretical method and technology of gaits control for the wheel-foot multi-joint mobile robot have been explored out. By precisely analyzing the obstacle performance and the workspace of the robot's feet, the constraints and efficiency of the robot have been illustrated clearly. After studying the features of various gaits, we also have designed four kinds of specific gaits for the wheel-foot multi-joint mobile robot, including the swing forward gait, the crab-lateral gait, the bent-knee forward gait and the wheel-turn gait, to verify the mobile ability and control effects of the robot. Then we research most fully on the control features, the attitudes of legs, the simulation effects and the fluctuation of the robot's body when walking with these four kinds of gaits, in order to fully understand the performance of the robot. The results of simulations and actual prototype tests have proved that the wheel-foot multi-joint mobile robot, with special mechanical structure and reasonable gaits planning, can move fast and steadily with versatile gaits in various complex terrains. The effectiveness of the theoretical exploration and the technical implementation has been fully proved in this paper.
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.
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.
This paper considers the distributed attitude synchronization problem for multiple spacecraft with external disturbances. Distributed discontinuous adaptive controller is designed based on the relative attitudes and a...
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ISBN:
(纸本)9781467355322
This paper considers the distributed attitude synchronization problem for multiple spacecraft with external disturbances. Distributed discontinuous adaptive controller is designed based on the relative attitudes and angular velocities of neighboring spacecraft and attitude synchronization can be reached for any communication graph containing a directed spanning tree. To tackle the chattering effect caused by the discontinuous controller, a continuous controller is further proposed, under which both the synchronization errors and the adaptive gains are ultimately bounded. Extensions to the case with a leader-follower communication graph with the leader as the spanning tree's root are further studied.
Electro-hydraulic servo systems(EHSSs) have been widely used in industrial and military applications for their high power-to-size ratio and the ability to supply huge ***,precise control of EHSSs cannot be easily obta...
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ISBN:
(纸本)9781479900305
Electro-hydraulic servo systems(EHSSs) have been widely used in industrial and military applications for their high power-to-size ratio and the ability to supply huge ***,precise control of EHSSs cannot be easily obtained due to their inner nonlinearity and parameter *** load is another factor to decrease the tracking performance of *** adaptive robust control(IARC) was proposed to improve the tracking performance of EHSS,but due to the poor parameter adapting speed,IARC can be further improved to have better *** projection type parameter estimation algorithm is redesigned to increase the adapting speed when parameter is changed.A fast adaptive robust control (FARC) is then proposed to speed up the parameter adapting speed,so that a better tracking performance of FARC is maintained. Simulation results show that the proposed FARC gives an improved tracking performance and a faster parameter adaptation.
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