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In this paper, a space-based manipulator system (SBMS) is researched. Although lots of work have been done about ground-based system for a long time, there are still exists a lot of problems for space-based manipulator because of the different dynamics modeling between them. A popular and interesting issue is coupled dynamics among the system. So, a special case, a SBMS with two manipulators symmetrically installed on a floating base, is modeled as the research object during whole work. Firstly, by establishing its kinematics and dynamics model, a general equation of motion is achieved. Then, a simulation test aiming at revealing the coupled phenomenon and how does the motion of manipulators impact on the floating base is conducted. The test results provide concrete proofs for our theoretical analysis.

An improved unit module of a novel mobile self-assembling modular robotic system is presented in this paper. Two continuous rotational DoFs are used in each module to implement both valuable self-locomotion and flexible reconfiguration. To achieve efficient exploration, unit module can implement two-dimensional locomotion independently and freely in a range of surface conditions in real world, even in environments with certain terrain challenges. With the help of three active connection mechanisms (ACMs), the module has great potential in assembling and reconfiguration to form complex three-dimensional structures. Preliminary locomotion tests in different environments demonstrate its effective mobility and potential applications for exploration. Several useful and easy realized configurations are explained with simulations at last.

Structured light systems are a simple and efficient tool in the field of 3D reconstruction. Existing calibration methods of structured light systems are either not precise or elastic. In this paper, an easy to use method is proposed. The calibration of a structured light system can accomplished with a good accuracy. The projector projects a checkerboard pattern rendered by OpenGL functions onto a planar board, and the coordinates of corner points in the projector image plane are adjusted to the target position with an iterative algorithm. Thus, the projector can "view" the printed chessboard pattern. The calibration of a projector becomes essentially the same as that of a monocular camera. Meanwhile, the projector calibration doesn't depend on a pre-calibrated camera, which makes errors of the camera calibration cannot effect the projector calibration. Experimental results show that the mean re-projection error of the projector is less than 1 pixel.

The vision systems mounted on mobile robots, which are moving on the rugged environment or enduring mechanical vibration, usually suffer from instable video during acquisition. In this paper, a fast video stabilization technique for robot application is presented. The proposed approach takes full advantage of intrinsic characteristics of the unwanted camera motion. There are four main steps involved in the proposed approach: feature extraction, motion estimation, motion compensation and undefined region mosaicing. We began with extracting the global features in 9 sub-regions of the current frame. The blocks with extracted features are matched in the reference frame from predicted start position. The computed motion consists of both expected and unexpected components. They are distinguished by motion smooth process and followed by motion compensation. As the result of frame shifting, some border regions are undefined. To solve this problem, inter-frames data is taken in consideration to fill those regions. A series of experiments with vivid data have been conducted. The results have revealed the effectiveness of the proposed technique.

Space manipulators are mainly used in the spatial loading task. According with the problems of the spatial loading diversity, the testing loading installing position and the utilization ratio of the test platform, the space manipulator is asked to evaluate the position and attitude of itself. This paper first put forward the concept of the Omni-directional Coefficient, which can evaluate any point in the attainable domain of the manipulators, with the combination of the manipulation's position message, and got the relationship between its position and attitude of all points in the attainable domain. Second, it represented the attitude of the end-effectors with attitude sphere. At last, proposed the method to evaluate the Omni-directional characters of the whole manipulator. This paper analyzed space manipulator experiment data analysis, using the method of numerical computation and graphic display. On the one hand, compared the Omni-directional Coefficient with the early quantitative representation used analytical method, on the other hand, vividly showed the Omni-directional Coefficient, Omni-directional space and the distribution of the Omni-directional in the attainable domain when the manipulator is the initial point. At last, we got the Omni-directional Coefficient of the whole manipulator by data analysis method.

The problems of diversity of tasks and non-structural environment have been put in front of robotic development, on the other hand, we urgently hope they consume low cost and have high reliability, so the method of multi-cooperation is wildly used. Then we would get the swarm robotics social system with the individual growing. In this paper, we proposed hierarchical organizational model to definite social order during task decomposition; then, we design the method of behavior generation based on proposition/transition Petri networks, which would assist the system to construct combined behavior using the sample individual behavior to solve a variety of tasks.

This paper presents a novel approach of vision stabilization, potentially applied to mobile robot or unmanned vehicle, which is inspired by the characteristics of human eye. Vision information processing is a key technology of intelligent mobile platform. However, in some condition, such as the vision module mount on the vehicle moving on the rugged ground, the system could not acquire stable vision, which influence the post-process of image information and make the observer uncomfortable. With video stabilization technology, the unwanted vibrations or shakes of video sequences is smoothed at real time speed. The algorithm proposed is mainly based on digital image stabilization technology, which divides the whole vision in 9 sub-area averagely, then processes searching and matching strategy by macro block with size of 16 X16 or 8×8 pixels. Both the start point for searching and motion vector are predicted by the motion trend. After the motion compensation procedure, the video is stabilized. During the procedure above, the edge area of the video is lost. In this paper, a recovery method inspired by human vision is discussed, which consider the duration of vision factors. With the evaluating a sequence of unstable images acquired by vision system on the mobile robot, we can draw the conclusion that the effectiveness and validation of the method aforementioned is implemented.

Foraging Task is a typical task on swarm robotic and Building Task (extend from blocks world) is widely used for testing performance of task planning in multi-robots. In this paper we combine foraging and building task as a new type task and implement on our swarm robotic system-SociBuilder. The platform is composed of three parts: active region, modules and many robots called Socibots. In order to execute the task automatically and effectively, we propose a new system architecture including three layers: human-computer interaction layer (HCI), planning layer and execution layer. For the same reason, we put forward a novel algorithm to adjust individual behavior dynamically. As a result of our experiments, Socibots use only local information and do not need communication with others in forage, and fewer individuals are centralized control for building task. The architecture and algorithm are effective in swarm robotics, which guide system to perform complex task with less burden.

In order to improve the speed and accuracy of the trajectory tracking control for 3R plane robot, a PD iterative self-learning control algorithm is proposed based on the PD iterative control algorithm. The error of target value and the actual value of this iteration is introduced into the PD learning gain to make the PD learning gain becomes a function of the error and to achieve the effect of self-learning. Simulation analysis of planar 3-link robot trajectory control shows that the proposed algorithm is better than unmodified in speed ability and accuracy. DOI: http://dx.doi.org/10.11591/telkomnika.v11i10.3427

Highway emergencies need to be quickly responded. In order to improve the efficiency of response time, emergency vehicles can be dispatched making use of a model-assisted system. This paper deals with the parameters determination of optimization model for emergency service dispatching. Based on extending previous work, calculation methods of four parameters are discussed. The parameters include weight co-efficient, travel time, potential delays and reassigning criterion. On the premise of ignoring sort of indicators, the weight values are determined by Analytic Hierarchy Process (AHP). Through utilizing the data of the integrated platform for Geographic Information System/Global Positioning System/General Packet Radio Service (GIS/GPS/GPRS), the travel time is calculated by the geometric analysis of the call location and the vehicle location. The remaining two parameters are obtained by statistical analysis of historical data. In order to verify the calculation methods of parameters, samples of actual data used are tested. The results show that weight co-efficient is an important parameter, which can impact the dispatching plan of optimization model. Reassigning criterion is also useful to improve system efficiency. Serious emergencies should be responded to with higher priority.

Travel time reliability is considered as an important index on the reliability of a road network. The objective of this article is to study the impact of ice and snowfall on the travel time reliability. For this purpose, the link travel time ISB-BPR (Ice and Snowfall Based- Bureau of Public Roads) model is proposed, which is based on the conventional BPR (Bureau of Public Roads) model and scale functions are added to the corresponding parameters of BPR. To follow the characteristics of route choice, SUE (stochastic user equilibrium) is adopted in this study. We develop an assessment methodology, which integrates sensitivity analysis of SUE and Monte Carlo simulation to evaluate the travel time reliability. The ISB-BPR model and the algorithm are applied to a hypothetical small road network and results are presented. The results show that travel time level of service and intensity of ice and snowfall have the most significant impact on the travel time reliability.