Journal of Robotics The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. On Indexicality, Direction of Arrival of Sound Sources, and Human-Robot Interaction Mon, 23 May 2016 08:06:59 +0000 We present the use of direction of arrival (DOA) of sound sources as an index during the interaction between humans and service robots. These indices follow the notion defined by the theory of interpretation of signs by Peirce. This notion establishes a strong physical relation between signs (DOAs) and objects being signified in specific contexts. With this in mind, we have modeled the call at a distance to a robot as indexical in nature. These indices can be later interpreted as the position of the user and the user herself/himself. The relation between the call and the emitter is formalized in our framework of development of service robots based on the SitLog programming language. In particular, we create a set of behaviours based on direction of arrival information to be used in the programming of tasks for service robots. Based on these behaviours, we have implemented four tasks which heavily rely on them: following a person, taking attendance of a class, playing Marco-Polo, and acting as a waiter in a restaurant. Ivan Meza, Caleb Rascon, Gibran Fuentes, and Luis A. Pineda Copyright © 2016 Ivan Meza et al. All rights reserved. Decentralized Cooperative Localization Approach for Autonomous Multirobot Systems Tue, 19 Apr 2016 07:44:17 +0000 This study proposes the use of a split covariance intersection algorithm (Split-CI) for decentralized multirobot cooperative localization. In the proposed method, each robot maintains a local cubature Kalman filter to estimate its own pose in a predefined coordinate frame. When a robot receives pose information from neighbouring robots, it employs a Split-CI based approach to fuse this received measurement with its local belief. The computational and communicative complexities of the proposed algorithm increase linearly with the number of robots in the multirobot systems (MRS). The proposed method does not require fully connected synchronous communication channels between robots; in fact, it is applicable for MRS with asynchronous and partially connected communication networks. The pose estimation error of the proposed method is bounded. As the proposed method is capable of handling independent and interdependent information of the estimations separately, it does not generate overconfidence state estimations. The performance of the proposed method is compared with several multirobot localization approaches. The simulation and experiment results demonstrate that the proposed algorithm outperforms the single-robot localization algorithms and achieves approximately the same estimation accuracy as the centralized cooperative localization approach, but with reduced computational and communicative cost. Thumeera R. Wanasinghe, George K. I. Mann, and Raymond G. Gosine Copyright © 2016 Thumeera R. Wanasinghe et al. All rights reserved. Service Arms with Unconventional Robotic Parameters for Intricate Workstations: Optimal Number and Dimensional Synthesis Wed, 13 Apr 2016 12:10:17 +0000 A task-oriented design strategy is presented in this paper for service manipulators. The tasks are normally defined in the form of working locations where the end-effector can work while avoiding the obstacles. To acquire feasible solutions in cluttered environments, the robotic parameters (D-H parameters) are allowed to take unconventional values. This enhances the solution space and it is observed that, by inducing this flexibility, the required number of degrees of freedom for fulfilling a given task can be reduced. A bilevel optimization problem is formulated with the outer layer utilizing the binary search method for minimizing the number of degrees of freedom. To enlarge the applicability domain of the proposed strategy, the upper limit of the number of joints is kept more than six. These allowable redundant joints would help in providing solution for intricate workcells. For each iteration of the upper level, a constrained nonlinear problem is solved for dimensional synthesis of the manipulator. The methodology is demonstrated through a case study of a realistic environment of a cluttered server room. A -link service arm, synthesized using the proposed method, is able to fulfill two different tasks effectively. Satwinder Singh and Ekta Singla Copyright © 2016 Satwinder Singh and Ekta Singla. All rights reserved. Gas Concentration Prediction Based on the Measured Data of a Coal Mine Rescue Robot Tue, 12 Apr 2016 16:11:00 +0000 The coal mine environment is complex and dangerous after gas accident; then a timely and effective rescue and relief work is necessary. Hence prediction of gas concentration in front of coal mine rescue robot is an important significance to ensure that the coal mine rescue robot carries out the exploration and search and rescue mission. In this paper, a gray neural network is proposed to predict the gas concentration 10 meters in front of the coal mine rescue robot based on the gas concentration, temperature, and wind speed of the current position and 1 meter in front. Subsequently the quantum genetic algorithm optimization gray neural network parameters of the gas concentration prediction method are proposed to get more accurate prediction of the gas concentration in the roadway. Experimental results show that a gray neural network optimized by the quantum genetic algorithm is more accurate for predicting the gas concentration. The overall prediction error is 9.12%, and the largest forecasting error is 11.36%; compared with gray neural network, the gas concentration prediction error increases by 55.23%. This means that the proposed method can better allow the coal mine rescue robot to accurately predict the gas concentration in the coal mine roadway. Xiliang Ma and Hua Zhu Copyright © 2016 Xiliang Ma and Hua Zhu. All rights reserved. Error Analysis and Adaptive-Robust Control of a 6-DoF Parallel Robot with Ball-Screw Drive Actuators Mon, 04 Apr 2016 13:35:45 +0000 Parallel kinematic machines (PKMs) are commonly used for tasks that require high precision and stiffness. In this sense, the rigidity of the drive system of the robot, which is composed of actuators and transmissions, plays a fundamental role. In this paper, ball-screw drive actuators are considered and a 6-degree of freedom (DoF) parallel robot with prismatic actuated joints is used as application case. A mathematical model of the ball-screw drive is proposed considering the most influencing sources of nonlinearity: sliding-dependent flexibility, backlash, and friction. Using this model, the most critical poses of the robot with respect to the kinematic mapping of the error from the joint- to the task-space are systematically investigated to obtain the workspace positional and rotational resolution, apart from control issues. Finally, a nonlinear adaptive-robust control algorithm for trajectory tracking, based on the minimization of the tracking error, is described and simulated. Navid Negahbani, Hermes Giberti, and Enrico Fiore Copyright © 2016 Navid Negahbani et al. All rights reserved. Artificial Knee Joints Actuators with Energy Recovery Capabilities: A Comparison of Performance Wed, 16 Mar 2016 11:09:46 +0000 The human knee absorbs more energy than it expends in level ground walking. For this reason it would be useful if the actuation system of a wearable robot for lower limbs was able to recover energy thus improving portability. Presently, we recognize three promising technologies with energy recovery capabilities already available in the literature: the Series Elastic Actuator (SEA), the Clutchable Series Elastic Actuator (C-SEA), and the flywheel Infinitely Variable Transmission (F-IVT) actuator. In this paper, a simulation model based comparison of the performance of these actuators is presented. The focus is on two performance indexes: the energy consumed by the electric motor per gait and the peak torque/power requested to the electric motor. Both quantities are related to the portability of the device: the former affects the size of the batteries for a given desired range; the latter affects the size and the weight of the electric motor. The results show that, besides some well-explained limitations of the presented methodology, the C-SEA is the most energy efficient whereas the F-IVT allows cutting down the motor torque/peak power strongly. The analysis also leads to defining how it is possible to improve the F-IVT to achieve a reduction of the energy consumption. Roberta Alò, Francesco Bottiglione, and Giacomo Mantriota Copyright © 2016 Roberta Alò et al. All rights reserved. Theoretical Design and First Test in Laboratory of a Composite Visual Servo-Based Target Spray Robotic System Wed, 16 Mar 2016 07:56:14 +0000 In order to spray onto the canopy of interval planting crop, an approach of using a target spray robot with a composite vision servo system based on monocular scene vision and monocular eye-in-hand vision was proposed. Scene camera was used to roughly locate target crop, and then the image-processing methods for background segmentation, crop canopy centroid extraction, and 3D positioning were studied. Eye-in-hand camera was used to precisely determine spray position of each crop. Based on the center and area of 2D minimum-enclosing-circle (MEC) of crop canopy, a method to calculate spray position and spray time was determined. In addition, locating algorithm for the MEC center in nozzle reference frame and the hand-eye calibration matrix were studied. The processing of a mechanical arm guiding nozzle to spray was divided into three stages: reset, alignment, and hovering spray, and servo method of each stage was investigated. For preliminary verification of the theoretical studies on the approach, a simplified experimental prototype containing one spray mechanical arm was built and some performance tests were carried out under controlled environment in laboratory. The results showed that the prototype could achieve the effect of “spraying while moving and accurately spraying on target.” Dongjie Zhao, Ying Zhao, Xuelei Wang, and Bin Zhang Copyright © 2016 Dongjie Zhao et al. All rights reserved. Motion Planning of Redundant Manipulators for Painting Uniform Thick Coating in Irregular Duct Sun, 06 Mar 2016 13:11:49 +0000 The paper presents a motion planning method of redundant manipulator for painting uniform thick coating on the interior of irregular duct of some aircrafts. Discontinuous peripheral painting method is employed by analyzing the restrictions during painting the duct. For improving the longitudinal uniformity of thick coating, the interlacing painting method plans two sets of sweeping paths and an interlacing distance between the starting paths of the two times of painting. The interlacing distance and overlapping distance are optimized by establishing and analyzing the model of longitudinal uniformity. To enhance the transverse uniformity, sweeping speeds for curved surfaces are calculated by the ratio of transfer efficiency after the basic sweeping speed for the plane is determined. The intertwining method, minimizing the sum of the weighed distances between the duct centerline and key points of the manipulator links, is employed for the joint trajectory planning without collision. The simulation and experiment results show that the redundant manipulators can finish painting the internal surface of the irregular S-shaped duct without collision. The maximum relative deviation is 16.3% and the thicknesses of all measurement points satisfy the acceptance criteria of the factory. Yan Chen, Wenzhuo Chen, Ken Chen, and Bo Li Copyright © 2016 Yan Chen et al. All rights reserved. Optimal Trajectory Planning for Glass-Handing Robot Based on Execution Time Acceleration and Jerk Wed, 10 Feb 2016 13:56:32 +0000 This study describes a trajectory planning method based on execution time, acceleration, and jerk to ensure that a glass-handing robot runs smoothly at execution time. The minimised objective function consists of the weighted sum of the square of the integral of the execution time, the integral of the acceleration, and the integral of the jerk, all of which are obtained through the weighted coefficient method. A three-dimensional kinematics model of the glass-handing robot is then established and nonuniform fifth-order -splines are used to interpolate its path points. The acceleration and jerk are expressed as functions of time through mathematical simulation. Simulation results show that the designed method for robot trajectory planning not only improves the working efficiency of the glass-handing robot but also ensures that it runs smoothly. Honggang Duan, Rongmin Zhang, Fei Yu, Jun Gao, and Yuan Chen Copyright © 2016 Honggang Duan et al. All rights reserved. A Novel Method of Dexterity Analysis for a 5-DOF Manipulator Thu, 04 Feb 2016 09:37:51 +0000 The dexterity characteristics and dexterous workspace features are applied as the considerable and key kinematics properties to evaluate the manipulator performance. In this paper, a novel method of the dexterity analysis with the character of graphic dexterity and a new concept of the spatial mapping envelope surface are proposed for a 5-degree of freedom (DOF) manipulator. Additionally, for an arbitrary selected point and a dexterous workspace, the dexterity characteristics and the dexterity conditions are drawn, respectively. Finally, the dexterous workspace of this 5-DOF manipulator is obtained and it can be utilized as the basis research of this manipulator in future such as the structure optimization and motion control. Wanjin Guo, Ruifeng Li, Chuqing Cao, and Yunfeng Gao Copyright © 2016 Wanjin Guo et al. All rights reserved. Obstacles Regions 3D-Perception Method for Mobile Robots Based on Visual Saliency Tue, 08 Dec 2015 08:48:52 +0000 A novel mobile robots 3D-perception obstacle regions method in indoor environment based on Improved Salient Region Extraction (ISRE) is proposed. This model acquires the original image by the Kinect sensor and then gains Original Salience Map (OSM) and Intensity Feature Map (IFM) from the original image by the salience filtering algorithm. The IFM was used as the input neutron of PCNN. In order to make the ignition range more exact, PCNN ignition pulse input was further improved as follows: point multiplication algorithm was taken between PCNN internal neuron and binarization salience image of OSM; then we determined the final ignition pulse input. The salience binarization region abstraction was fulfilled by improved PCNN multiple iterations finally. Finally, the binarization area was mapped to the depth map obtained by Kinect sensor, and mobile robot can achieve the obstacle localization function. The method was conducted on a mobile robot (Pioneer3-DX). The experimental results demonstrated the feasibility and effectiveness of the proposed algorithm. Tao Xu, Songmin Jia, Zhengyin Dong, and Xiuzhi Li Copyright © 2015 Tao Xu et al. All rights reserved. Study and Experiment on a Wheat Precision Seeding Robot Tue, 24 Nov 2015 07:24:18 +0000 The wheat precision seeding technology provided an advanced agricultural support for the high yield of wheat. But the lack of effective agricultural machine made this technique difficult to apply widely. In this paper a wheel mobile robot to achieve the wheat precision seeding technology was designed. The kinematic model of the robot was built and simulated. And experimental study was taken under different operating conditions. Because of multiple effort factors, a quadratic orthogonal rotation combination design method was applied in the experiments, identifying the main factors by analysis. Then the field test was carried out according to the main factors. The experiment results showed that the qualified rates of seeding exceed 93% in different sowing speed. That reached the agronomic requirements of wheat precision seeding. Lin Haibo, Dong Shuliang, Liu Zunmin, and Yi Chuijie Copyright © 2015 Lin Haibo et al. All rights reserved. Kinematic Analysis of a Partially Decoupled 3-DOF Parallel Wrist Mon, 23 Nov 2015 07:10:40 +0000 A unique spherical parallel wrist with three partially decoupled rotational degrees of freedom (DOFs) is introduced in this paper. The mechanism has the significant advantages of few singularities and simple partially decoupled kinematics. A modified parallel wrist is optimized to have the least link interference workspace. Finally, the decoupled motion is studied in detail to exhibit the kinematic performance of the mechanism. Fan Zhang, Yunping Zhu, Tomonari Furukawa, and Wanqing Song Copyright © 2015 Fan Zhang et al. All rights reserved. Mathematical Modeling and Analysis of Multirobot Cooperative Hunting Behaviors Sun, 01 Nov 2015 09:27:27 +0000 This paper presents a mathematical model of multirobot cooperative hunting behavior. Multiple robots try to search for and surround a prey. When a robot detects a prey it forms a following team. When another “searching” robot detects the same prey, the robots form a new following team. Until four robots have detected the same prey, the prey disappears from the simulation and the robots return to searching for other prey. If a following team fails to be joined by another robot within a certain time limit the team is disbanded and the robots return to searching state. The mathematical model is formulated by a set of rate equations. The evolution of robot collective hunting behaviors represents the transition between different states of robots. The complex collective hunting behavior emerges through local interaction. The paper presents numerical solutions to normalized versions of the model equations and provides both a steady state and a collaboration ratio analysis. The value of the delay time is shown through mathematical modeling to be a strong factor in the performance of the system as well as the relative numbers of the searching robots and the prey. Yong Song, Yibin Li, Caihong Li, and Xin Ma Copyright © 2015 Yong Song et al. All rights reserved. Dynamic Model Identification for 6-DOF Industrial Robots Thu, 29 Oct 2015 12:47:14 +0000 A complete and systematic procedure for the dynamical parameters identification of industrial robot manipulator is presented. The system model of robot including joint friction model is linear with respect to the dynamical parameters. Identification experiments are carried out for a 6-degree-of-freedom (DOF) ER-16 robot. Relevant data is sampled while the robot is tracking optimal trajectories that excite the system. The artificial bee colony algorithm is introduced to estimate the unknown parameters. And we validate the dynamical model according to torque prediction accuracy. All the results are presented to demonstrate the efficiency of our proposed identification algorithm and the accuracy of the identified robot model. Li Ding, Hongtao Wu, Yu Yao, and Yuxuan Yang Copyright © 2015 Li Ding et al. All rights reserved. Field Results of a Navigation Architecture with Timing Constraints Thu, 29 Oct 2015 08:32:55 +0000 This paper presents results of field tests of a mobile robot controlled by a navigation architecture accounting for timing constraints in an indoor environment. Dependability properties characterize the effects of disturbances on the ability to successfully accomplish any assigned missions, described in terms of the stability of an equilibrium state identified with a goal location. The stability is analyzed using Contraction theory. A localization system based on artificial landmarks is used to obtain location estimates that enable the robot to autonomously cover large distances. Monte Carlo tests assess the architecture under different real environment conditions including recovering from disturbing events such as landmark detection failures, robot kidnapping, unexpected collisions, and changes in the density of obstacles in the environment. Tests include long-run missions of around 2900 m lasting for 4.5 hours. Jorge Silva, Joao Sequeira, and Cristina Santos Copyright © 2015 Jorge Silva et al. All rights reserved. Integrating UAVs into the Cloud Using the Concept of the Web of Things Thu, 15 Oct 2015 08:30:51 +0000 UAVs, Unmanned Aerial Vehicles, have gained significant attention recently, due to the increasingly growing range of applications. Most UAVs use radio frequency transmission to communicate with the ground station to receive commands and send data. However, this model of communication restricts the user to being in specific locations and limits missions to narrow areas. This paper proposes a Cloud Computing (CC) integration where the UAVs become part of the cloud infrastructure and can be accessed ubiquitously. This concept is similar to the Internet of Things (IoT) where smart objects are connected to the Internet and are given unique identification. Moreover, to provide an appropriate way of communication, UAV resources are developed as web services. They provide their resources and services through a uniform interface using the RESTful HTTP architecture. This concept is relevant to the Web of Things (WoT) that provides smart objects with interfaces to be accessed through the World Wide Web (WWW). However, in UAVs, not only the web services are computational services but they are also physical elements affecting and affected by the real world environment. Sara Mahmoud, Nader Mohamed, and Jameela Al-Jaroodi Copyright © 2015 Sara Mahmoud et al. All rights reserved. Biologically Inspired Robotics Thu, 08 Oct 2015 06:58:41 +0000 Liwei Shi, Maki K. Habib, Nan Xiao, and Huosheng Hu Copyright © 2015 Liwei Shi et al. All rights reserved. Development and Motion Testing of a Robotic Ray Mon, 05 Oct 2015 08:56:25 +0000 Biomimetics takes nature as a model for inspiration to immensely help abstract new principles and ideas to develop various devices for real applications. In order to improve the stability and maneuvering of biomimetic fish like underwater propulsors, we selected bluespotted ray that propel themselves by taking advantage of their pectoral fins as target. First, a biomimetic robotic undulating fin driven propulsor was built based on the simplified pectoral structure of living bluespotted ray. The mechanical structure and control circuit were then presented. The fin undulating motion patterns, fin ray angle, and fin shape to be investigated are briefly introduced. Later, the kinematic analysis of fin ray and the whole fin is discussed. The influence of various kinematic parameters and morphological parameters on the average propulsion velocity of the propulsor was analyzed. Finally, we conclude that the average propulsion velocity generally increases with the increase of kinematic parameters such as frequency, amplitude, and wavelength, respectively. Moreover, it also has a certain relationship with fin undulating motion patterns, fin ray angle, fin shape, and fin aspect ratio. Jianhui He and Yonghua Zhang Copyright © 2015 Jianhui He and Yonghua Zhang. All rights reserved. Rolling Locomotion Control of a Biologically Inspired Quadruped Robot Based on Energy Compensation Mon, 05 Oct 2015 08:43:41 +0000 We have developed a biologically inspired reconfigurable quadruped robot which can perform walking and rolling locomotion and transform between walking and rolling by reconfiguring its legs. This paper presents an approach to control rolling locomotion with the biologically inspired quadruped robot. For controlling rolling locomotion, a controller which can compensate robot’s energy loss during rolling locomotion is designed based on a dynamic model of the quadruped robot. The dynamic model describes planar rolling locomotion based on an assumption that the quadruped robot does not fall down while rolling and the influences of collision and contact with the ground, and it is applied for computing the mechanical energy and a plant in a numerical simulation. The numerical simulation of rolling locomotion on the flat ground verifies the effectiveness of the proposed controller. The simulation results show that the quadruped robot can perform periodic rolling locomotion with the proposed energy-based controller. In conclusion, it is shown that the proposed control approach is effective in achieving the periodic rolling locomotion on the flat ground. Takuma Nemoto, Rajesh Elara Mohan, and Masami Iwase Copyright © 2015 Takuma Nemoto et al. All rights reserved. Action Selection and Operant Conditioning: A Neurorobotic Implementation Sun, 04 Oct 2015 12:21:28 +0000 Action selection (AS) is thought to represent the mechanism involved by natural agents when deciding what should be the next move or action. Is there a functional elementary core sustaining this cognitive process? Could we reproduce the mechanism with an artificial agent and more specifically in a neurorobotic paradigm? Unsupervised autonomous robots may require a decision-making skill to evolve in the real world and the bioinspired approach is the avenue explored through this paper. We propose simulating an AS process by using a small spiking neural network (SNN) as the lower neural organisms, in order to control virtual and physical robots. We base our AS process on a simple central pattern generator (CPG), decision neurons, sensory neurons, and motor neurons as the main circuit components. As novelty, this study targets a specific operant conditioning (OC) context which is relevant in an AS process; choices do influence future sensory feedback. Using a simple adaptive scenario, we show the complementarity interaction of both phenomena. We also suggest that this AS kernel could be a fast track model to efficiently design complex SNN which include a growing number of input stimuli and motor outputs. Our results demonstrate that merging AS and OC brings flexibility to the behavior in generic dynamical situations. André Cyr and Frédéric Thériault Copyright © 2015 André Cyr and Frédéric Thériault. All rights reserved. Bioinspired Tracking Control of High Speed Nonholonomic Ground Vehicles Sun, 04 Oct 2015 09:44:53 +0000 The behavior of nature’s predators is considered for designing a high speed tracking controller for nonholonomic vehicles, whose dynamics are represented using a unicycle model. To ensure that the vehicle behaves intuitively and mimics the biologically inspired predator-prey interaction, saturation constraints based on Ackermann steering kinematics are added. A new strategy for mapping commands back into a viable envelope is introduced, and the restrictions are accounted for using Lyapunov stability criteria. Following verification of the saturation constraints, the proposed algorithm was implemented on a testing platform. Stable trajectories of up to 9 m/s were achieved. The results presented show that the algorithm demonstrates significant promise in high speed trajectory tracking with obstacle avoidance. Adam Shoemaker and Alexander Leonessa Copyright © 2015 Adam Shoemaker and Alexander Leonessa. All rights reserved. Unified Switching between Active Flying and Perching of a Bioinspired Robot Using Impedance Control Sun, 04 Oct 2015 07:22:59 +0000 Currently, a bottleneck problem for battery-powered microflying robots is time of endurance. Inspired by flying animal behavior in nature, an innovative mechanism with active flying and perching in the three-dimensional space was proposed to greatly increase mission life and more importantly execute tasks perching on an object in the stationary way. In prior work, we have developed some prototypes of flying and perching robots. However, when the robots switch between flying and perching, it is a challenging issue to deal with the contact between the robot and environment under the traditional position control without considering the stationary obstacle and external force. Therefore, we propose a unified impedance control approach for bioinspired flying and perching robots to smoothly contact with the environment. The dynamic model of the bioinspired robot is deduced, and the proposed impedance control method is employed to control the contact force and displacement with the environment. Simulations including the top perching and side perching and the preliminary experiments were conducted to validate the proposed method. Both simulation and experimental results validate the feasibility of the proposed control methods for controlling a bioinspired flying and perching robot. Shanshan Du, Heping Chen, Yong Liu, and Runting Hu Copyright © 2015 Shanshan Du et al. All rights reserved. Development and Evaluation of Compact Robot Imitating a Hermit Crab for Inspecting the Outer Surface of Pipes Thu, 01 Oct 2015 12:33:41 +0000 Terrestrial hermit crabs which are a type of hermit crabs live on land, whereas typical hermit crabs inhabit the sea. They have an ability of climbing a tree vertically. Their claws allow them to hang on the tree. In this study, an outer-pipe inspection robot was developed. Its locomotion mechanism was developed in imitation of the terrestrial hermit crab’s claws. It is equipped with two rimless wheels. Each of the spokes is tipped with a neodymium magnet, which allows the robot to remain attached to even a vertical steel pipe. Moreover, the robot has a mechanism for adjusting the camber angle of the right and left wheels, allowing it to tightly grip pipes with different diameters. Experiments were conducted to check the performance of the robot using steel pipes with different diameters, placed horizontally, vertically, or obliquely. The robot attempted to move a certain distance along a pipe, and its success rate was measured. It was found that the robot could successfully travel along pipes with vertical orientations, although it sometimes fell from oblique or horizontal pipes. The most likely reason for this is identified and discussed. Certain results were obtained in laboratory. Further experiments in actual environment are required. Naoto Imajo, Yogo Takada, and Mikiji Kashinoki Copyright © 2015 Naoto Imajo et al. All rights reserved. Sparse Approximation for Nonrigid Structure from Motion Thu, 01 Oct 2015 12:32:45 +0000 This paper introduces applying a novel sparse approximation method into solving nonrigid structure from motion problem in trajectory space. Instead of generating a truncated traditional trajectory basis, this method uses an atom dictionary which includes a set of overcomplete bases to estimate the real shape of the deformable object. Yet, it still runs reliably and can get an optimal result. On the other hand, it does not need to consider the size of predefined trajectory bases; that is to say, there is no need to truncate the trajectory basis. The mentioned method is very easy to implement and the only trouble which needs to be solved is an -regularized least squares problem. This paper not only presents a new thought, but also gives out a simple but effective solution for the nonrigid structure from motion problem. Yaming Wang, Xiaomeng Yan, Junbao Zheng, and Mingfeng Jiang Copyright © 2015 Yaming Wang et al. All rights reserved. Unmanned Aerial Vehicle Navigation Using Wide-Field Optical Flow and Inertial Sensors Thu, 01 Oct 2015 12:31:29 +0000 This paper offers a set of novel navigation techniques that rely on the use of inertial sensors and wide-field optical flow information. The aircraft ground velocity and attitude states are estimated with an Unscented Information Filter (UIF) and are evaluated with respect to two sets of experimental flight data collected from an Unmanned Aerial Vehicle (UAV). Two different formulations are proposed, a full state formulation including velocity and attitude and a simplified formulation which assumes that the lateral and vertical velocity of the aircraft are negligible. An additional state is also considered within each formulation to recover the image distance which can be measured using a laser rangefinder. The results demonstrate that the full state formulation is able to estimate the aircraft ground velocity to within 1.3 m/s of a GPS receiver solution used as reference “truth” and regulate attitude angles within 1.4 degrees standard deviation of error for both sets of flight data. Matthew B. Rhudy, Yu Gu, Haiyang Chao, and Jason N. Gross Copyright © 2015 Matthew B. Rhudy et al. All rights reserved. Inverse Kinematic Analysis and Evaluation of a Robot for Nondestructive Testing Application Thu, 01 Oct 2015 08:59:17 +0000 The robot system has been utilized in the nondestructive testing field in recent years. However, only a few studies have focused on the application of ultrasonic testing for complex work pieces with the robot system. The inverse kinematics problem of the 6-DOF robot should be resolved before the ultrasonic testing task. A new effective solution for curved-surface scanning with a 6-DOF robot system is proposed in this study. A new arm-wrist separateness method is adopted to solve the inverse problem of the robot system. Eight solutions of the joint angles can be acquired with the proposed inverse kinematics method. The shortest distance rule is adopted to optimize the inverse kinematics solutions. The best joint-angle solution is identified. Furthermore, a 3D-application software is developed to simulate ultrasonic trajectory planning for complex-shape work pieces with a 6-DOF robot. Finally, the validity of the scanning method is verified based on the C-scan results of a work piece with a curved surface. The developed robot ultrasonic testing system is validated. The proposed method provides an effective solution to this problem and would greatly benefit the development of industrial nondestructive testing. Zongxing Lu, Chunguang Xu, Qinxue Pan, Xinyu Zhao, and Xinliang Li Copyright © 2015 Zongxing Lu et al. All rights reserved. Simulation of Octopus Arm Based on Coupled CPGs Thu, 01 Oct 2015 08:37:48 +0000 The octopus arm has attracted many researchers’ interests and became a research hot spot because of its amazing features. Several dynamic models inspired by an octopus arm are presented to realize the structure with a large number of degrees of freedom. The octopus arm is made of a soft material introducing high-dimensionality, nonlinearity, and elasticity, which makes the octopus arm difficult to control. In this paper, three coupled central pattern generators (CPGs) are built and a 2-dimensional dynamic model of the octopus arm is presented to explore possible strategies of the octopus movement control. And the CPGs’ signals treated as activation are added on the ventral, dorsal, and transversal sides, respectively. The effects of the octopus arm are discussed when the parameters of the CPGs are changed. Simulations show that the octopus arm movements are mainly determined by the shapes of three CPGs’ phase diagrams. Therefore, some locomotion modes are supposed to be embedded in the neuromuscular system of the octopus arm. And the octopus arm movements can be achieved by modulating the parameters of the CPGs. The results are beneficial for researchers to understand the octopus movement further. Juan Tian and Qiang Lu Copyright © 2015 Juan Tian and Qiang Lu. All rights reserved. A Framework for Multidisciplinary Optimization of a Balancing Mechanism for an Industrial Robot Mon, 27 Jul 2015 08:19:20 +0000 The paper presents a framework that can be used to design and optimize a balancing mechanism for an industrial robot. The framework has the capability to optimize three different concepts: a mechanical, a pneumatic, and a hydropneumatic. Several disciplines are included in the framework, such as dynamic and static analyses of the robot performance. Optimization is performed for each concept and the obtained optimal designs are all better than the reference design. This means that the framework can be used as a tool both to optimize the balancing mechanism and also to support concept selection. Johan A. Persson, Xiaolong Feng, Daniel Wappling, and Johan Ölvander Copyright © 2015 Johan A. Persson et al. All rights reserved. Visual Control System of a Spraying Robot for Hyphantria cunea Larva Nets Sun, 31 May 2015 11:53:07 +0000 In order to implement automatic spraying on Hyphantria cunea larva nets, a spraying robot system with monocular hand-eye coordination and smart targeting abilities was designed according to the target net features. The system realized spatial two-dimensional motions driven by step motors on linear guide rails. Images were processed in real-time to extract the net curtain targets defined using the border area, and the optimal spraying position was then determined. An identification algorithm based on the global net image to distinguish targets before and after spray was proposed. A simulation environment was designed to verify the correctness of this method. Results showed that the highest rate of over spray is 288.5%, and the spray miss rate is 0. Ying Zhao, Qun Sun, Chong Wang, and Cuihua Zhang Copyright © 2015 Ying Zhao et al. All rights reserved.