For dismantling heavy structure under special environment in radioactivity, there are many problems which should be tele-operated and feedback a cutting force for cutting a thick structure such as concrete. When operator dismantles a thick heavy concrete structure, it is in sufficient to judge whether robot is contacting or not with environment by using only vision information. To overcome this problem, force feedback and impedance model based bilateral control are introduced. The sliding mode control with sliding perturbation observer (SMCSPO) based bilateral control is applied and surveyed to a single rod hydraulic cylinder in this paper. The sliding mode control is used for robustness against a disturbance. The sliding perturbation observer is used for estimation of a reaction force such as cutting force. The bilateral control is executed using the information of reaction force estimated by SMCSPO. The contribution of this paper is that the estimation method and bilateral control of the single rod hydraulic cylinder are introduced and discussed by experiment.
Static balance of an articulated robot arm at various configurations requires a torque compensating for the gravitational torque of each joint due to the robot mass. Such compensation torque can be provided by a spring-based counterbalance mechanism. However, simple installation of a counterbalance mechanism at each pitch joint does not work because the gravitational torque at each joint is dependent on other joints. In this paper, a 6 DOF industrial robot arm based on the parallelogram for multi-DOF counterbalancing is proposed to cope with this problem. Two passive counterbalance mechanisms are applied to pitch joints, which reduces the required torque at each joint by compensating the gravitational torque. The performance of this mechanism is evaluated experimentally.
A design methodology for parametric design optimization of washing machine door is presented. We develop a motion simulator and a robotic door to simulate the various motion of washing machine doors. The motion of the washing machine door is related to hinge parameters. Springs and dampers are usually used in the hinge of washing machine door for controlling motion of the door. A physical simulator of the door motion is used for finding candidate parameters of the hinge and a robotic door whose motion is controlled algorithmically is used for consumer tests. Through the consumer evaluation on the robotic motion, the optimized parameters are determined. We find the optimal parameters as a function of angle and angular velocity of the door.
Previous shape sensors including bend sensors and optic fiber based sensors are widely used in various applications including goniometer and surgical robots. But theses sensors have large nonlinearity, limited in the range of sensing curvature, and sometimes are expensive. This study suggests a new concept of bend sensor using cable-conduit which consists of the outer sheath and the inner wire. The outer sheath is made of helical coil whose length of the central line changes as the sheath bends. This length change of the central line can be measured with the length change of the inner cable. The modeling and the experimental results show that the output signal of the proposed sensor is linearly related with the bend angle of the sheath with root mean square error of 5.3% of 450° sensing range. Also the polynomial calibration of the sensor can decrease the root mean square error to 2.1% of the full sensing range.
We present a region-based approach for accurate pose estimation of small mechanical components. Our algorithm consists of two key phases: Multi-view object co-segmentation and pose estimation. In the first phase, we explain an automatic method to extract binary masks of a target object captured from multiple viewpoints. For initialization, we assume the target object is bounded by the convex volume of interest defined by a few user inputs. The co-segmented target object shares the same geometric representation in space, and has distinctive color models from those of the backgrounds. In the second phase, we retrieve a 3D model instance with correct upright orientation, and estimate a relative pose of the object observed from images. Our energy function, combining region and boundary terms for the proposed measures, maximizes the overlapping regions and boundaries between the multi-view co-segmentations and projected masks of the reference model. Based on high-quality co-segmentations consistent across all different viewpoints, our final results are accurate model indices and pose parameters of the extracted object. We demonstrate the effectiveness of the proposed method using various examples.
Using an inverse of the geometric Jacobian matrix is one of the most popular ways to control robot manipulators, because the Jacobian matrix contains the relationship between joint space velocities and operational space velocities. However, the control algorithm based on Jacobian matrix has algorithmic singularities: The robot manipulator becomes unstable when the Jacobian matrix loses rank. To solve this problem, various methods such as damped and filtered inverse have been proposed, but comparative studies to evaluate the performance of these algorithms are insufficient. Thus, this paper deals with a comparative analysis of six representative singularity avoidance algorithms: Damped Pseudo Inverse, Error Damped Pseudo Inverse, Scaled Jacobian Transpose, Selectively Damped Inverse, Filtered Inverse, and Task Transition Method. Especially, these algorithms are verified through computer simulations with a virtual model of a humanoid robot, THORMANG, in order to evaluate tracking error, computational time, and multiple task performance. With the experimental results, this paper contains a deep discussion about the effectiveness and limitations of each algorithm.
This paper proposes combination of a cognitive agent architecture named Soar (State, operator, and result) and ROS (Robot Operating System), which can be a basic framework for a robot agent to interact and cope with its environment more intelligently and appropriately. The proposed Soar-ROS human-robot interaction (HRI) agent understands a set of human’s commands by voice recognition and chooses to properly react to the command according to the symbol detected by image recognition, implemented on a humanoid robot. The robotic agent is allowed to refuse to follow an inappropriate command like “go” after it has seen the symbol ‘X’ which represents that an abnormal or immoral situation has occurred. This simple but meaningful HRI task is successfully experimented on the proposed Soar-ROS platform with a small humanoid robot, which implies that extending the present hybrid platform to artificial moral agent is possible.
In this paper, we introduce the pipe cleaning robot developed to clean the gas impurities of the iron manufacturing equipments. The pipe cleaning robot is composed of two driving modules and one cleaning module. 2-DOF joint units were developed for connections among the modules. To maximize the traction power of the driving parts, it became caterpillar type. The extension links have been developed to maintain the traction force in case the pipe inner diameters change. Three cleaning modules were developed for the effective cleaning in the pipe. The driving and cleaning performance tests of the pipe cleaning robot were proceeded in the field of the iron manufacturing equipments.
This paper presents the development of a 3D printer based piezo-driven vertical micro-positioning stage. The stage consists of two flexure bridge structures which amplify and transfer the horizontal motion of the piezo-element into vertical motion of the end-effector. The stage is fabricated with ABS material using a precision 3D printer. This enables a one-body design eliminating the need for assembly, and significantly increases the freedom in design while shortening fabrication time. The design of the stage was optimized using response surface analysis method. Experimental results are presented which demonstrate 100nm stepping in the vertical out-of-plane direction. The results demonstrate the future possibilities of applying 3D printers and ABS material in fabricating linear driven motion stages.
The Expanded Guide Circle (EGC) method has been originally proposed as the guidance navigation method for improving the efficiency of the remote operation using the sensory information. The previous algorithm is, however, concerned only for the omni-directional mobile robot, so it needs to suggest a suitable one for a mobile robot with non-holonomic constraints. The ego-kinematic transform is a method to map points of R2 into the ego-kinematic space which implicitly represents non-holonomic constraints for admissible paths. Thus, robots with non-holonomic constraints in the ego-kinematic space can be considered as “free-flying object”. In this paper, we propose an effective obstacle avoidance method for mobile robots with non-holonomic constraints by applying EGC method in the ego-kinematic space using the ego-kinematic transformation. This proposed method shows that it works better for non-holonomic mobile robots such as differential-drive robot than the original one. The simulation results show its effectiveness of performance.
Unmanned military vehicles (UMVs) will be increasingly applied to the various military operations. These UMVs are most commonly characterized as dealing with “4D” task – dull, dirty, dangerous and difficult with automations. Although most of the UMVs are designed to a high degree of autonomy, the human operator will still intervene in the robots operation, and tele-operate them to achieve his or her mission. Thus, operator capacity, along with robot autonomy and user interface, is one of the important design factors in the research and development of the UMVs. In this paper, we propose the method to assess the operator capacity of the UMVs. The method is comprised of the 6 steps (problem, assumption, goal function identification, operator task analysis, task modeling & simulation, results and assessment), and herein colored Petri-nets are used for the modeling and simulation. Further, an illustrative example is described at the end of this paper.