17661722
Locomotion Analysis and Experiment for Climbing Motion of RPRS
A new Reconfigurable Planetary Robot System (RPRS) is introduced in this paper. The locomotion mechanism, especially the static force analysis and the climbing ability for different configurations of the multiple child-robots are presented in detail. The basic configurations of two child-robots systems were given in three modes: connecting in series with arm in front or back and combining to a loop with grasper. The simulation results of these three configurations based on static analysis demonstrate that the climbing ability is closely correlated to their configurations. Compared the results, the conclusion can be obtained that the loop configuration has the best effect than others on slope climbing. The actual experiments of the child-robots system have illustrated the simulating results, and an exciting phenomenon has emerged, which shows that all the configurations can climb bigger gradient than the simulating results. The phenomenon rightly discloses the characteristic of the novel architecture of the child-robot.
152660
Gaits-transferable CPG controller for a snake-like robot
With slim and legless body, particular ball articulation, and rhythmic locomotion, a nature snake adapted itself to many terrains under the control of a neuron system. Based on analyzing the locomotion mechanism, the main functional features of the motor system in snakes are specified in detail. Furthermore, a bidirectional cyclic inhibitory (BCI) CPG model is applied for the first time to imitate the pattern generation for the locomotion control of the snake-like robot, and its characteristics are discussed, particularly for the generation of three kinds of rhythmic locomotion. Moreover, we introduce the neuron network organized by the BCI-CPGs connected in line with unilateral excitation to switch automatically locomotion pattern of a snake-like robot under different commands from the higher level control neuron and present a necessary condition for the CPG neuron network to sustain a rhythmic output. The validity for the generation of different kinds of rhythmic locomotion modes by the CPG network are verified by the dynamic simulations and experiments. This research provided a new method to model the generation mechanism of the rhythmic pattern of the snake.
206600042
Multiagent Reinforcement Learning for a Planetary Exploration Multirobot System
In a planetary rover system called “SMC rover”, the motion coordination between robots is a key problem to be solved. Multiagent reinforcement learning methods for multirobot coordination strategy learning are investigated. A reinforcement learning based coordination mechanism is proposed for the exploration system. Four-robot climbing a slope is studied in detail as an instance. The actions of the robots are divided into two layers and realized respectively, which simplified the complexity of the climbing task. A Q-Learning based multirobot coordination strategy mechanism is proposed for the climbing mission. An OpenGL 3D simulation platform is used to verify the strategy and the learning results.
21075507
BP Networks Based Trajectory Planning and Inverse Kinematics of a Reconfigurable Mars Rover
The inverse kinematics of series manipulators presents an inherent complexity due to their various structures and kinematics constraints. To a novel reconfigurable Mars rover's arm, the inverse kinematics had been solved by numerical method combined with space geometry relations, but the complex calculating process can not be utilized in real-time control. In this paper, some actions in common use are programmed in the child rover, and the BP neural network was used to solve the inverse kinematics and trajectory planning. To a desired trajectory, some solutions by direct kinematics algorithms and geometry relations corresponding to the trajectory were used as the BP network's training data set, and the non-linear mapping from joint-variable space to operation-variable space was obtained with iterative training and learning method. The results show the output of training is consistent with the desired path, and the obtained reference trajectory is smooth.
206544153
Analysis of creeping locomotion of a snake robot on a slope
Biological snakes' diverse locomotion modes and physiology make them supremely adapted for environment. To realize these snakes' noticeable features, we have developed a snake-like robot that has no any forward direction driving force. To enlarge the environment-adaptable ability of our robot, in this study we discuss the creeping locomotion of our snake-like robot on a slope. A computer simulator is presented for analysis of the creeping locomotion of our snake-like robot on a slope, and the environment-adaptable body shape for the creeping locomotion of the snake-like robot on slope is also derived through this simulator.
14083445
Network-based reconfiguration routes for a self-reconfigurable robot
This paper presents a network-based analysis approach for the reconfiguration problem of a self-reconfigurable robot. The self-reconfigurable modular robot named “AMOEBA-I” has nine kinds of non-isomorphic configurations that consist of a configuration network. Each configuration of the robot is defined to be a node in the weighted and directed configuration network. The transformation from one configuration to another is represented by a directed path with nonnegative weight. Graph theory is applied in the reconfiguration analysis, where reconfiguration route, reconfigurable matrix and route matrix are defined according to the topological information of these configurations. Algorithms in graph theory have been used in enumerating the available reconfiguration routes and deciding the best reconfiguration route. Numerical analysis and experimental simulation results prove the validity of the approach proposed in this paper. And it is potentially suitable for other self-reconfigurable robots’ configuration control and reconfiguration planning.
26657378
Palmprint Identification using Boosting Local Binary Pattern
Local binary pattern (LBP) is a powerful texture descriptor that is gray-scale and rotation invariant according to T. Ojala et al. (2002). Because texture is one of the most clearly observable features in low-resolution palmprint images, we think local binary pattern based features are very discriminative for palmprint identification. In this paper, we propose a palmprint identification approach using boosted local binary pattern based classifiers. The palmprint area is scanned with a scalable sub-window from which local binary pattern histograms are extracted to represent the local features of a palmprint image. The multi-class problem is transformed into a two-class one of intra- and extra-class by classifying every pair of palmprint images as intra-class or extra-class ones in the work of B. Moghaddam et al. (1996). We use the AdaBoost algorithm in the work of Y. Freund and R.E. Schapire (1997) to select those sub-windows that are more discriminative for classification. Weak classifiers are constructed based on the Chi square distance between two corresponding local binary pattern histograms. Experiments on the UST-HK palmprint database show competitive performance
20301405
Unequal-arm Adaptive Rood Pattern Search with Early Terminations For Fast Block-matching Motion Estimation on H.264
Based on a rood-shaped pattern of the motion-vector displacement distribution inherently resulted from block-matching motion estimation, a series of adaptive rood pattern search (ARPS) algorithms have been introduced. Among them, the unequal-arm ARPS has achieved superior performance on many accounts while maintaining a fairly close rate-distortion performance compared with that of the full search. In this paper, an enhanced version of the unequal-arm ARPS is introduced by incorporating early terminations at both the initial search and the refined local search stages. Its performance was compared with that of the UMHexagonS fast block-matching motion estimation algorithm based on the JM-9.3 software encoder. The experimental results show that the unequal-arm ARPS with early terminations has yielded significant search efficiency gain while consistently maintaining a fairly close rate-distortion performance compared with that of the UMHexagonS. Furthermore, the proposed algorithm is fairly simple on implementation
40597607
Towards an Analysis of Source-Rewriting Anonymous Systems in a Lossy Environment
Anonymity that protects the identity of participants is a basic requirement for many network-based applications. For practical anonymous communication systems, strong anonymity, reliability and efficiency are three critical properties, but they may degrade in a lossy environment (nodes failure or links crash). This paper takes Crowds system as an example and statistically analyzes the degradation of these properties in lossy environment. Theoretical deduction and numerical analysis illustrate that Crowds is reliable enough to tolerate nodes failure, but both efficiency and anonymity will degrade. With the theoretical analysis results in this paper, a Crowds system operator can adjust the parameter pf to be tolerant of different node failure rate and node corruption rate.
39558628
Combined adaptive beamforming with space-time block coding for multi-antenna communications
Aiming at the multi-antenna communication systems, a downlink transmit scheme combining adaptive beamforming (ABF) with space-time block coding (STBC) is first presented, which utilizes the maximization of the output mean signal-to-noise ratio (SNR) and the minimization of the symbol error rate (SER) upper bound of the three widely used modulations as the design criteria. Then, based on the moment generating function (MGF) and the Gauss-Chebyshev integration, a simple and accurate numerical method is presented to analyze the SER performance of the system with the new transmit scheme under the three commonly used modulations. Finally, computer simulation results demonstrate the effectiveness and superiority of the proposed strategy.
7375220
Dynamic User Modeling for Sketch-Based User Interface
This paper presents a strategy of dynamic user modeling for sketch-based user interface. A user model is defined as an incremental decision tree for a specific user. A drawing style modeling process is designed to model user's temporal drawing performances among inputting strokes, and to predict the possible shape in term of fuzzy matching. A user mediation process is proposed based on relevance feedback to capture users' drawing intentions and refine the recognition results. Experiments prove efficiency of the method.