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This paper proposes a calibration method that accurately estimates six parameters between the two centers of 2-D light detection and ranging (LIDAR) and a rotating platform. This method uses a simple plane, and to the best of our knowledge, it is the first to enable full-degree-of-freedom (DOF) estimation without additional hardware. The key concept behind this method is a decoupling property, in which the direction of a line on a plane does not contain 3-DOF translation terms. Based on this, a cost function for rotation is constructed, and 3-DOF rotation parameters are estimated. With this rotation, the remaining 3-DOF translation parameters are calculated in a manner that minimizes the cost function for translation only. In other words, an original 6-DOF problem is decoupled into two 3-DOF estimation problems. Given these cost functions, degenerate cases are mathematically analyzed for known cases (incomplete), and the robustness is numerically tested for all possible cases (complete). The performance of the method is validated by extensive simulations and experimentations, and the estimated parameters from the proposed method demonstrate better accuracy than previous methods.

Planning in a cluttered environment under differential constraints is a difficult problem because the planner must satisfy the external constraints that arise from obstacles in the environment and the internal constraints due to the kinematic/dynamic limitations of the robot. This paper proposes a novel Spline-based Rapidly-exploring Random Tree (SRRT) algorithm which treats both the external and internal constraints simultaneously and efficiently. The computationally expensive numerical integration of the system dynamics is replaced by an efficient spline curve parameterization. In addition, the SRRT guarantees continuity of curvature along the path satisfying any upper-bounded curvature constraints. This paper presents the underlying theory to the SRRT algorithm and presents simulation and experiment results of a mobile robot efficiently navigating through cluttered environments.

An adjusted assessment model based on benefit-cost analysis (BCA) is proposed for evaluating the economic efficiency of automated construction technologies. In contrast to conventional BCA, the model does not compare monetary values, but the differences in benefits and costs between traditional and automated construction methods. To verify the usefulness of the model, it was applied to a real-scale building construction project that used a fully automated building construction system, and the face validity of the model was confirmed. The results indicate that the model can support decision makers in identifying valuable benefit factors and in assessing the cost effectiveness of the system.

In this paper, a dependable humanoid navigation system is proposed by considering many difficulties in humanoid navigation based on bipedal locomotion in an uncertain environment. In particular, we propose a layered architecture to resolve complicated problems through a hierarchical manner. Within the proposed software architecture, a walking path planner, a walking footstep planner, and a walking pattern generator are integrated in a hierarchy to create a reliable motion that overcomes foot slippage and localization sensor noise. Each layer is designed to overcome difficulties originating from bipedal locomotion such as unstable dynamics, inclusion of a sinusoidal noise component in the localization sensor measurement, and disturbance regarding discrete footstepping. The designed navigation system is implemented on a human-sized experimental humanoid platform and is tested for the evaluation of its reliability and robustness in various tasks.

The building construction industry has adapted well to the need to overcome traditional problems of safety, productivity, and quality on construction sites. Advanced technologies and systems developed outside the building industry are also being introduced to meet the new demands of today's challenges. In particular, the high-tech robots used in the erection of structural steel frames in high-rise buildings in order not to expose human workers to unsafe conditions. In addition, an automated construction system based on improved bolting robots has been developed in Korea. However, the harsh environment of construction sites adversely affects the various sensitive machines, sensors, and devices that comprise the robot construction systems. To minimize the effects of the adverse environment on robot performance, it is believed that a Construction Factory (CF) is required. This is a special workspace providing a stable and favourable work environment for the construction robot. In this study, we developed several CF alternatives for the realization of more desirable automated construction environment, and evaluated them from the aspects of wind speed and air temperature using Computational Fluid Dynamics (CFD) simulation. The results showed that a CF with a closed roof and bottom was the best CF option for robot construction, and it can be helpful to reduce the potential cost overruns and time delays for CF construction.

In this paper, we propose a path planner for a robotic vacuum cleaner (RVC). In the design of the planner, we consider two main issues: (1) human-friendly path generation and (2) low computational load. First, we analyze how human move and suggest a hypothesis that human navigate in a way that minimizes the sum of muscle and brain energy. By imitating the human path, we propose a human- friendly path planner. Also, the designed planner requires a low amount of computations which not only extends the battery running time but also decreases the hardware cost of the RVC. Experimental results show that the proposed path gives a more favorable impression to customers than conventional paths.

A hard contact is an impact that occurs when the robot contacts a stiff environment with a high velocity. In the pretransition phase of the hard contact, it is important to maintain stability while reducing succeeding force peaks and the duration time. For these purposes, we propose two control methods. One is a suppression controller that suppresses position rebounds in-between the impact time. The other is a flexible-damped joint with a joint damping controller. The flexible-damped joint is a new joint type designed to increase the hardware damping. It is controlled by a novel controller, called the joint damping controller, to enhance damping. The major advantage of the proposed methods is a guaranteed stability. The performance of the proposed methods is validated via several comparative experiments.

In this paper, we address a new technique for automatic construction of steel structure in high-rise buildings termed RCA system (Robotics & Crane based Automated Construction System). RCA system can be divided into four core systems: 1) Monitoring and control system, 2) Material assembly system, 3) Beam assembly system, 4) Construction Factory (CF) system. Through our research, we expect that this new technique will increase the construction efficiency and it will alleviate the man power shortage problem.

Many studies which try to integrate construction technologies with robotic technologies have been actively progressing. It is critical for an assessment model of the economical efficiency of new technologies to ensure the correct investment and the spread of these new technologies. However, an assessment model of economical efficiency of automated construction technology to evaluate properly various influencing factors in terms of technology and economy is relatively unsatisfied as there are no practical cases. Therefore, our research team has developed a new assessment process for automated construction technologies as a decision tool, inspired by benefit-cost analysis. This presented process was employed to evaluate the test-bed and the results show that the BI and CI are 1.24 and 5.22, respectively, and economic efficiency is 0.24. The results indicate that the applications of four new technologies present a significantly strong benefit and respectively large cost, compared to the traditional process. As establishing an assessment model of an automated construction system which has not previously been known, it is expected to understand the effect and potential power of the application of robot technology to the construction industry. For further study, it is necessary for the integration method to be developed because of the degree of difference between BI and CI.

In this paper, we propose a new design of a flexible enveloping grasper for pick and place tasks with the low complexity in manipulation and task planning for the purpose of practical use in the near future. Flexible material for the grasper has many advantageous characteristics inherently including robustness against manipulation errors and the ability to increase contact area with a grasped object and the grasping force. Compliance of the grasper material also contributes to reduction in complexity of the processes such as the force control, sensor-motor coordination, and manipulation by self-adaptation. Two properties, flexibility and compliance, mentioned above help the proposed grasper minimize the internal forces in a passive manner and achieve the successful force distribution with self-adaptivity when performing enveloping grasping. In order to demonstrate our work, we have constructed 2 different prototypes of flexible enveloping grasper. Experimental results validate robust performances of the proposed grasper.

The best node selection problem, that distinguishes a node with the best state among multiply connected nodes, is one of the fundamental problem in robotics. However, a systematic solution has not been proposed by its ambiguity characteristics. To make the problem tractable, we reduce the scope of the original problem. Then, we suggest a novel index that systematically judges a required time step needed for a node to be the best. Furthermore, we suggest a new estimation technique that outperforms than previous approaches by 4.94 times in its settling time.

Electric vehicles (EVs) are poised to become a solution for consumers wanting to reduce their energy footprint. But along with the upside for the environment and money saving, it also comes with safety concerns about the EV charging equipment being installed in homes and public charging stations. Many safety regulatory authorities and certifying organisations across the world have done researches on safety of equipment, and have developed many standards as outcomes. For this reason, manufacturers are facing tough challenges of getting their products compliant with various international standards. The engineering standard developed in this study will be a solution for the difficulties of dealing with UL 2594 and IEC 61851 that electric vehicle supply equipment (EVSE) manufacturers have been facing. The study mainly focuses on EV portable cord-set, however the outcome can be applied to general SAE type EVSE.

In this paper, we introduce a new technique for automatic construction of steel frames in high-rise buildings. Basically, we combine advanced robotic technologies to building construction techniques. Four main topics will be developed such as: 1) Planning and synthesis of automatic construction system (ACS); 2) Development of construction factory(CF) system with climbing oil-pressured robot; 3) Core techniques for automatic assembly for steel frames; and 4) Intelligent resource management system. We expect that this new technique will increase the construction efficiency and will alleviate the manpower shortage problem in the aging society. For the development of the proposed system, two main ideas will be suggested. The first idea is to utilize a transportation system for the robot. One of the main problems of the automatic construction is that the size of the construction factory is very huge while that of the robot is not. To alleviate the problem, we suggest a transportation system which combines a rail with a boom. The second idea is to use a wire suspended positioning system. In the construction, it is a main issue to bring the guiders and beams in a pre-planned position with an accuracy of 2 mm. Nowadays, it is operated by two skilled workers. Through our research, We want to implement it automatically by utilizing the wire suspended positioning system which is controlled by the cable of a tower crane and multiple wires.

In this paper we propose a practical roadmap for mobile robots with differential wheel base. The roadmap is designed for a rectilinear environment which covers most of indoor buildings. In designing the roadmap, we put emphasis on two issues: (1) human friendly path and (2) low computation. First, we analyze how human move. From the human movement, we find out that human navigate in a way that minimizes the sum of a muscle and a brain energy. On the basis of the human path, we suggest an algorithm with low calculations. Experimental results show that the path generated by our method is more human-friendly and natural.

In this paper, an algorithm for door detection using a cheap PC-camera is developed based on the Bayesian network in a hallway where doors are located at various depth. The open/close status of the door is also important in developing a GVG-SLAM and we extracted five important door features from the image and distance data. We applied the Bayesian network algorithm and an entropy concept to increase the robustness. Experiment result shows that the proposed algorithm can help the GVG-SLAM of mobile robot by successfully identifying the status of the door.

GVG has been effectively used as a sensor based navigation tool using 360/spl deg/ sensor data. For mobile guide robot applications, however, we can only use 180/spl deg/ sensor data and the robustness of the navigation algorithm is critical for successful applications. For that purpose, the robot should be equipped with three capabilities. Those are 1) incremental GVG construction, 2) robust GVG navigation and 3) navigation strategy that just uses half of the sensor scan, i.e. 180/spl deg/. In this paper, we propose a GVG navigation algorithm that has above 3 capabilities. We firstly propose a method that can estimate the invisible 180/spl deg/ range from previous range data. Moreover, we suggest a way of robust GVG navigation algorithm by using a sensor data matching technique. The simulation result validates that the proposed algorithm can incrementally and robustly navigate the semi-unstructured map by using 180/spl deg/ sensor scan.

This paper present the development of the human-mobile communication system using Electro Oculo Gram(EOG) signals. An “Ideal Velocity Shape” signal processing algorithm is proposed to extract position data wh ere the eyes are focusing on from the noisy and drift included EOG signals. Additionally, an efficient algorithm for the detection of various eye-lip movements such as blink and wink is suggested. Two experiments were performed for the validation of human-mobile communication system. One is point stabilization of mobile robot, using extracted eye focusing position data. The other is moving target following experiment using various eye-lip movements as mobile robot's command.

In this paper, we consider hard contact force control law which shows good performance as well as enhanced stability and robustness. First, we consider hard contact transition such as hammering when the manipulator's approaching velocity is high or the environment is very stiff. In hard contact, phase transition can be divided into two definitely different phases, "pre-transition phase" and "transition phase". Here we define the "pre-transition phase" and propose a novel controller named as "suppression controller" which is not only stable but also simple to implement. Based on this result, we suggest a hard contact force control scheme which is named "hybrid suppression controller". The effectiveness of these approaches are verified via experiments using POSTECH 1 DOF DD arm.

In this paper, we consider hard contact transition such as hammering when the manipulator's approaching velocity is high or the environment is very stiff. In contact transition, phase transition can be divided into two definitely different phases, "pre-transition phase" and "transition phase". Here we define the "pre-transition phase" and we propose three control methods. First, we propose a novel controller named as "suppression controller" which is not only stable but also simple to implement. Second, we present passive damper named as "flexible-damped joint" which is a good solution to circumvent the pre-transition phase. Third, we suggest a stable and simple controller which can maximize joint damping and minimize recontact velocity in the flexible-damped joint. It is named as "joint damping controller". The effectiveness of these three approaches are verified via experiments using the POSTECH 1-DOF DD arm.