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2015 International Conference on Fluid Power and Mechatronics

作者： Lianpeng Zhang Yu Yang Chifu Yang Junwei Han State Key Laboratory of Robotics and System Harbin Institute of Technology

Redundant-drive shaking tables composed of more than one shaking tables are indispensible test equipments for anti-seismic study of long-span structures and are experiencing rapid development recently. However, the control strategy of the shaking tables system is greatly complex and there isn't a common accepted method now. This paper proposed two degree of freedom(DOF) control strategies for the shaking tables system composed of two identical redundant-drive electro-hydraulic servo shaking table: six DOFs control strategy and twelve DOFs control strategy. According to different control principles, build two kinds of coordinates, derive the geometric motion relationship of the platform or load and the hydraulic cylinders, and then use zero-position geometric linearity technique to obtain simplified coordinate transformation matrixes between platform or load motion space and the hydraulic cylinders space. The control system model with DOF control strategy and dynamic model of the shaking tables are built using the Matlab/Simulink and Sim Mechanics software. Simulation experiments are carried out and the test results indicate that both the control strategies can realize the accurate motion of the platform and verify the feasibility and validity of the proposed control strategies. In the end, this paper compared the two DOF control strategies and analyzed the advantages and disadvantages of each control strategy.

关键词： electrohydraulic srevo shaking tables degree of freedom control transformation matrix

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Effects of Stride Length and Frequency on Mobile Performance of a Hydraulic Hexapod Robot

Effects of Stride Length and Frequency on Mobile Performance...

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2015 International Conference on Fluid Power and Mechatronics

作者： Yiqun Liu Liang Ding Zhen Liu Haitao Yu Ma Jin Haibo Gao Zongquan Deng State Key Laboratory of Robotics and System Harbin Institute of Technology

Gait parameters play a significant role in the locomotion of a hexapod walking robot used for different goals. Stride length and frequency are the two most important and useful gait parameters of hexapod robots. This paper presents the configuration of a hydraulic hexapod walking robot. The typical gaits of hexapod robot are introduced and the kinematic model of the robot is established. Four performance metrics to evaluate the mobility performance of the hexapod robot are chosen and analyzed, and they are maximum foot force, maximum actuation cylinder force, maximum power and maximum flow. Prototype of the hydraulic hexapod robot is developed, and four performance metrics are measured according to a series of walking experiments of the robot prototype under different stride length and frequency. The influences of stride length and walking frequency on mobility performance of the hexapod robot are studied. It can be found that the foot force, cylinder force, power and flow consumption increase with the increase of stride length and walking frequency. The findings of this paper can be applied for the motion planning and control of legged robots.

关键词： hexapod robot hydraulic drive stride length frequency mobility performance

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Application of Cycle Variable Pitch Propeller to Morphing Unmanned Aerial Vehicles

Application of Cycle Variable Pitch Propeller to Morphing Un...

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IEEE International Conference on Information and Automation

作者： Liang Gao Jie Zhao Yanhe Zhu Hongzhe Jin Hongwei Wang Hegao Cai State Key Laboratory of Robotics and System Harbin Institute of Technology

ISBN: (纸本)9781467391054

Most of morphing aircrafts control the flight attitude by the deformation of aircraft wing, however morphing UAV is not limited to the deformation of the wing. This paper studies cyclic variable pitch propeller system which can generate control torque. According to mathematical model of cyclic variable pitch propeller based on propeller blade element theory, the study analyzes the principle and researches the way of attitude control. Simulation based on model of flight dynamics shows control torque produced by the system is effective on maneuverability of the morphing UAV. And experimental measurement has been done with six-axis force/torque transducer, results show the force and moment generated by CVPP system as the change of pitch angle conforms with the mathematical model and CVPP system have the ability to replace conventional control surfaces.

关键词： Variable Pitch Morphing Aircraft Attitude Control Propeller

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THE WORKING PRINCIPLE AND EXCITATION METHOD OF A STEP PERISTALSIS PIEZOELECTRIC ACTUATOR

THE WORKING PRINCIPLE AND EXCITATION METHOD OF A STEP PERIST...

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2015全国压电和声波理论及器件技术研讨会

作者： Dong-dong SHI Ying-xiang LIU Wei-shan CHEN Jun-kao LIU State Key Laboratory of Robotics and System Harbin Institute of Technology

A step peristalsis actuator using piezoelectric stacks is proposed,designed and *** proposed actuator contains four piezoelectric stacks located in U-shaped:the two horizontal piezoelectric stacks are used to push the runner,while the two vertical piezoelectric stacks are used to change the contact states between the two feet and the *** the working principle for bidirectional-linear-driving is *** to the working principle,the exciting method is developed to obtain the sequence control signals of the piezoelectric *** is found that the step peristalsis piezoelectric actuator can achieve the accuracy of nanometer and be used as a bidirectional *** last,the driving power of the step peristalsis piezoelectric actuator is investigated by theoretical analysis and *** present,the proposed design can be used as a long-stroke,ultra-precision and bidirectional piezoelectric actuator.

关键词： The step peristalsis actuator Piezoelectric stacks Driving power Ultra-precision Long-stroke

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Hydrodynamic Interactions between a Cylinder and an Attached Elastic Plate

Hydrodynamic Interactions between a Cylinder and an Attached...

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2015 International Conference on Fluid Power and Mechatronics

作者： DONG Dibo CHEN Weishan SHI Shengjun HAN Zhenbo HOU Zhenxiu State Key Laboratory of Robotics and System Harbin Institute of Technology

An elastic plate behind a rigid cylinder in viscous flow is modeled numerically by an immersed boundary-lattice Boltzmann method(IB-LBM). The hydrodynamic interactions of a upstream cylinder and a adjacent passively flapping plate are studied by varying the length and bending stiffness of the plate. Two patterns of the plate are found in the simulation results, if the plate is short enough, it would curl up because of the attraction of the suction zone behind the cylinder. With the increase of the plate's length, it will stretch and flap in a stable period. The cylinder has a strong influence on the dynamics of the plate and the plate also changes the vortex shedding of the cylinder and the shape of suction zone. With a downstream adjacent plate, the cylinder can always enjoys a drag reduction, longer the plate is, less drag the cylinder experiences. The vortex shedding frequency of the cylinder is larger than that of the single cylinder and equal to the plate's flapping frequency. This study may help to understand the energy saving of flexible bodies stay in the wake of a rigid structure and the hydrodynamic interactions between them.

关键词： Hydrodynamic interactions Flexible plate Lattice Boltzmann method

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Path Planning Based on Bi-RRT Algorithm for Redundant Manipulator

Path Planning Based on Bi-RRT Algorithm for Redundant Manipu...

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2015 International Conference on Electrical, Automation and Mechanical Engineering(EAME 2015)

作者： X.Z.Zang W.T.Yu L.Zhang Sajid Iqbal State Key Laboratory of Robotics and System Harbin Institute of Technology

ISBN: (纸本)9781510806528

For the manipulator which is used to execute maintenance tasks in the Tokamak reactor,solving the problem of collision-free path planning is the *** paper introduced the Single-RRT and Bi-RRT algorithms then used BiRRT algorithm to make the path planning for the motion of a redundant manipulator in the vacuum chamber,finally made a Matlab simulation *** result shows that RRT algorithm can effectively achieve the purpose of collision-free path planning,and using Bi-RRT can reduce the number of searches and invalid search points compared with *** better path can be obtained and used in the actual control by means of multiple searches and replacements.

关键词： redundant manipulator path planning RRT algorithm Tokamak

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Turning Gait Planning and Simulation Validation of a Hydraulic Hexapod Robot

Turning Gait Planning and Simulation Validation of a Hydraul...

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2015 International Conference on Fluid Power and Mechatronics

作者： Haibo Gao Ma Jin Yiqun Liu Liang Ding Haitao Yu Zongquan Deng State Key Laboratory of Robotics and System Harbin Institute of Technology

Gait planning is an important part of robotics research, and turning gait is an important and useful walking gait of a hexapod robot. But researches on turning gait of hexapod robots are limited. This paper presents the structure of a hydraulic hexapod walking robot. The coordinate of the leg is defined, and the positive and inverse kinematic equation of the leg is established. Foot trajectory based on cycloid during swing phase is planned, and the foot trajectory of support phase is also planned. A turning gait can be divided into the first half cycle and the second half cycle, and the turning gait based on tripod gait of the hexapod robot is planned. A virtual simulation platform for the hexapod robot is developed based on Vortex software. The platform consists of robot model module, manipulator and control module, terrain model module and footterrain interaction module. The simulation process is presented, and the turning gait is realized on the simulation platform. Finally, the simulation results show that the foot trajectory curves and the joint angle curves are smooth, and there is no conflict between the curves of six legs. The rationality and feasibility of the proposed method has been verified.

关键词： hexapod robot turning gait foot trajectory simulation validation hydraulic drive

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Neural Adaptive Tracking Control for Wheeled Mobile Robots

Neural Adaptive Tracking Control for Wheeled Mobile Robots

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2015 International Conference on Fluid Power and Mechatronics

作者： Zhencai Li Yang Wang Xingguo Song Zhen Liu State Key Laboratory of Robotics and System (Harbin Institute of Technology)

In this study, an adaptive control method is proposed by combining the tracking controller with neural torque controller for wheeled mobile robots. The kinematics and dynamics control laws are developed, and stability of control system is ensured by standard Lyapunov theory. For the trajectory tracking control of the wheeled mobile robot(WMR), we design an efficient neural network control that can manage the unmodeled extra disturbances and unstructured dynamics model of WMR. Especially, we have chosen radial basis function(RBF) neural networks to approximate the nonlinear function. By tuning the neural network weights, ensure the small tracking errors when WMR travels with the bounded input signals. Simulations illustrate the soundness of the proposed control theme for the desired tracking trajectory by Matlab-simulation.

关键词： Tracking control,wheeled mobile robot(WMR),adaptive control,neural network(NN),Lyapunov theory

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Topology Structure Synthesis and Analysis of Spatial Pyramid Deployable Truss Structures for Satellite SAR Antenna

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 683-692页

作者： WANG Yan DENG Zongquan LIU Rongqiang YANG Hui GUO Hongwei State Key Laboratory of Robotics and System Harbin Institute of Technology

Many attentions for structural synthesis are paid to planar linkages and parallel mechanisms, while design novel pyramid deployable truss structure（PDTS） of satellite SAR mainly depends on experience of designer. To design novel configuration of PDTS, a two-step topology structure synthesis and analysis approach is proposed. Firstly, a conceptual configuration of PDTS is synthesized. Weighted graph and weighted adjacency matrix are established to realize topological description for PDTS. Graph properties are then summarized to distinguish differentia between PDTS and other type structures. According to graph properties, a procedure for synthesis conceptual configuration of PDTS is presented. Secondly, join relationship of components in a PDTS is analyzed. Kinematic chain and corresponding incidence/adjacency matrix are employed to analyze join relationship of PDTS. Properties and simplified rules of kinematic chain are extracted to construct kinematic chain. A procedure for construction kinematic chain of PDTS is then established. Finally, with this two-step approach all 11 rectangular pyramid deployable structures whose folded state is planar are discovered and their kinematic chains are constructed. Based on synthesis results, a novel deployable support structure for satellite SAR is designed. The proposed research can be applied to obtain some novel PDTSs, which is of great importance to design some novel deployable support structures for satellite SAR antenna.

关键词： structural synthesis deployable truss structure spatial linkage graph theory SAR antenna

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Indoor Objects 3D Modeling Based on RGB-D Camera for Robot Vision

Indoor Objects 3D Modeling Based on RGB-D Camera for Robot V...

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2015 International Conference on Fluid Power and Mechatronics

作者： Guangsheng Shi Lijun Zhao Ke Wang Yunfeng Gao Yihuan Liu State key laboratory of robotics and system Harbin Institute of Technology

The 3D-object modeling hasbecome one hottopic in robot vision field for robots locating, grabbing and dropping operation. In this paper, we propose anefficient method of object modeling based RGB-D camera(Kinect) that can help the robot to carry out operation task. Our method is divided into three stage: firstly, point clouds of scene containing object are captured from thecamera and plane-segmentation to extract clusters of object;secondly, the preprocessed method is used to filter noise and outlier points;Points pair-wise alignment by way of our proposed pairs rejection strategy, global consistent alignment of the complete object and object-centered representation easy to manipulate. Besides, for the well-known loop closure problem, we optimize the pose and eliminate the accumulations base on the ICP improved algorithm. Finally, the proposed method is validated by the modeling of several household objects.

关键词： ICP 3D object modeling noise reduction loop optimization

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