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In this paper we face the challenging problem of takeoff and landing on sloped surfaces for a VTOL aerial vehicle. We define the general conditions for a safe and robust maneuver and we analyze and compare two classes of methods to fulfill these conditions: free-flight vs. passively-tethered. Focusing on the less studied tethered method, we show its advantages w.r.t. the free-flight method thanks...
This paper presents a practical control approach for series elastic actuators(SEAs) to generate the desired torque. Specifically, the controller is applicable to both linear and nonlinear SEAs and it works well even in the presence of unknown payload parameters and external disturbances. Via the analysis and transformation of the SEA dynamics, a lumped disturbance signal is constructed and a form...
Obstacle Detection is a central problem for any robotic system, and critical for autonomous systems that travel at high speeds in unpredictable environment. This is often achieved through scene depth estimation, by various means. When fast motion is considered, the detection range must be longer enough to allow for safe avoidance and path planning. Current solutions often make assumption on the motion...
Tethered Segway is a robotic platform inspired by human climbers. It is a two-wheeled mobile platform tethered to the top of a structure in order to climb steep surfaces with varying slopes, such as domes. The unstructured environment may cause uncertainties in the dynamic behavior of the robot while operating on different parts of the dome. In this paper analysis and synthesis of a robust controller...
In this paper, a robust trajectory tracking control strategy for a quadrotor flying robot is developed. At first, the quadrotor's dynamic model is obtained by Euler — Newton approach. Then, control strategy, consist of a robust linear H∞ control to track transitional movements for reference trajectory and a robust nonlinear H∞ control for rotational movements and rejecting the external disturbances...
Episodic memory can store time sequential events and retrieve them anytime with specific cues. However, if the episodic memory only stores events comprised of actions and objects, execution of episodes may fail if current situation is different from the settings it learned in. As a solution, we propose Deep C-ART (Context-Adaptive Resonance Theory) which considers not only time sequential events but...
A gesture is not performed in only one action but a combination of continuous actions. It is very important to know the start and end of a gesture for accurate gesture recognition. In this paper, to extract a meaningful gesture portion in an online situation, we introduce a method that can distinguish the start and end of a gesture. Then, we describe the method of recognizing an extracted gesture.
Applications based on groups of self-organized mobile robots and — more generically — agents are becoming pervasive in communication, monitoring, traffic and transportation systems. Their advantage is the possibility of providing services without the existence of a previously defined infrastructure and with a high degree of autonomy. On the other hand, physical agents, in general, are prone to failures,...
Mobile robots are advanced systems that often need to operate in unstructured environments, which increases software complexity. Many components are key to the overall reliability and safety of a robot, yet reducing the risk of errors by making the software resilient is both complicated and expensive. A commercially successful robot has to remain safe while providing as much as possible from the functionality...
Circle detection from digital images is a necessary operation in many robotics and computer vision tasks to facilitate shape and object recognition. We propose and analyze a novel method, based on line segment detection and circle completeness verification, to detect circles in images. The key idea is to use line segments instead of raw edge pixels to get the circle candidates followed by a verification...
This paper presents the implementations of Model Predictive Control for the standing balance control of a humanoid to reject external disturbances. The strategies allow the robot to have a compliant behaviour against external forces resulting in a stable and smooth response. The first, ZMP based controller, compensates for the center of mass deviation while the second, attitude controller, regulates...
The paper concerns fault-tolerant control of a real battery assembly system. The proposed framework is based on an interval analysis approach, which along with max-plus algebra, allows describing uncertain discrete event system such as the production one being considered in this paper. Having a mathematical system description, a model predictive control-based fault tolerant strategy is developed which...
In this paper, a new blending method for Graphene nanoplatelets was developed. A chaotic system based robust delta robot was designed. Both the speed of the mixer motor and position of the propeller were chaotically changed. Performance of the systems was evaluated by a material analysis method. The results showed that the proposed method has a better performance than statically mounted mixers.
Since input shaping control is based on open-loop control technique, robustness to modeling error is crucial for successful application of it. The robustness of input shaping control has conventionally been evaluated from the ratio of residual vibration amplitude with input shaping to that without input shaping. However there has been no serious consideration on robustness measures of input shaping...
The best control performance in mechatronic systems cannot be obtained by only control algorithms, because the control is effective only within the performance range realizable by an actuator system in practice. To obtain the best control performance, therefore, the mechanical system should be designed considering the control performance first. It is, however, difficult to expect the control performance...
In this paper, a novel contribution to highlight the conflict between energy efficiency, robustness and stability is presented. Energy optimization is combined with robust scheduling techniques to analyze the trade-off. In rescheduling, slack is often used in order to protect a schedule from disruptions. However, results from the literature on energy minimization show that a reduction in energy consumption...
Nonprehensile manipulation can play a significant role in complex robotic scenarios, especially for maneuvering non-graspable objects. A big challenge is to construct a robust skill for pushing highly-diverse objects. We present a strategy for pushing unknown objects that differ widely in their properties. For this purpose we introduce the concept of a pushing corridor for cluttered environments that...
Disturbance observer(DOB) has been known as a simple robust control method to reject disturbances. Design of Q filters is considered as the most important design technique for the DOB design to compensate for the possible improperness of the inverse model of the plant as well as a non minimum phase. Many efforts on Q-filter design have been accomplished to realize a stable filter for the inverse of...
Multiagent systems have been a major area of research for the last 15 years. This interest has been motivated by tasks that can be executed more rapidly in a collaborative manner or that are nearly impossible to carry out otherwise. To be effective, the agents need to have the notion of a common goal shared by the entire network (for instance, a desired formation) and individual control laws to realize...
Path Planning is one of the exclusive research area in the Robotics. It basically focuses on the robot motion from the initial position to final position such that it must avoid the hurdles and finally reach the goal in optimal path. But it is not an easy task because many conditions are included for the efficiency of final result like working on different environments, known or unknown target etc...
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