this paper analyzes the comfort of wheelchair users when a sliding-mode trajectory-tracking controller is used. the transmission of the horizontal (fore-and-aft) vibration to the head-neck complex (HNC) in the seated ...
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ISBN:
(纸本)9789898111319
this paper analyzes the comfort of wheelchair users when a sliding-mode trajectory-tracking controller is used. the transmission of the horizontal (fore-and-aft) vibration to the head-neck complex (HNC) in the seated human body may cause unacceptable discomfort and motion sickness. A double-inverted pendulum model with two degrees of freedom is considered as a model for the HNC. the user comfort is examined not only in the time domain (using the fourth power vibration dose value), but also in the frequency domain (using the cross-spectral density method). For measuring the acceleration of the wheelchair, along the trajectory, an inertial measurement unit was used.
Autonomous exploration of mazes requires finding a "center of gravity" keeping the robot safe from colliding withthe walls. that is similar to the obstacle avoidance problem as the maze walls are obstacles ...
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ISBN:
(纸本)9789897583049
Autonomous exploration of mazes requires finding a "center of gravity" keeping the robot safe from colliding withthe walls. that is similar to the obstacle avoidance problem as the maze walls are obstacles that the robot must avoid. In this report, we describe an approach to controlling robot movements in a maze using an Inverse Compensation Vector (ICV) that is not much more computationally demanding than calculating a centroid point. the ICV is used to correct the robot velocity vector that determines the direction and the speed, so the robot moves in the maze staying securely within the passages between the walls. We have tested the approach using a simulator of a physical robot equipped with a planar LIDAR scanner. Our experiments showed that using the ICV to compensate robot velocity is an effective motion-correction method. Furthermore, we augmented the algorithm with preprocessing steps that alleviate problems caused by noisy raw data coming from actual LIDAR scans of a physical maze.
In this paper we present the novel concepts incorporated in a planetary surface exploration rover design that is currently under development. the Multitasking Rover (MTR) aims to demonstrate functionality that will co...
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ISBN:
(纸本)9728865600
In this paper we present the novel concepts incorporated in a planetary surface exploration rover design that is currently under development. the Multitasking Rover (MTR) aims to demonstrate functionality that will cover many of the current and future needs such as rough-terrain mobility, modularity and upgradeability. the rover system has enhanced mobility characteristics. It operates in conjunction with Science Packs (SPs) and Tool Packs (TPs)-modules attached to the main frame of the rover, which are either special tools or science instruments and alter the operation capabilities of the system.
Using conventional rigid industrial manipulators for service robotics applications typically demands huge efforts for safety measurements resulting in high installation and operation costs. We present how the BioRob r...
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ISBN:
(纸本)9781617387197
Using conventional rigid industrial manipulators for service robotics applications typically demands huge efforts for safety measurements resulting in high installation and operation costs. We present how the BioRob robot arm is based on a combination of compliant actuation and lightweight mechanical design to obtain the flexibility, mobility and, most important, the inherent safety properties needed to implement effective and safe service robotics applications. We discuss the sensors and control structure used to damp the oscillations caused by the significant joint compliance of the arm and to obtain the accuracy needed for the intended applications. the concluding example of a typical pick and place application with teaching by manual guidance illustrates the benefits of the BioRob design for service robotics applications.
this paper discusses the placement of cameras in order to achieve the highest possible localization accuracy. It is reached by using several cameras with redundant fields of views. A camera model is introduced and the...
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ISBN:
(纸本)9789897580406
this paper discusses the placement of cameras in order to achieve the highest possible localization accuracy. It is reached by using several cameras with redundant fields of views. A camera model is introduced and the components which cause the localization errors are identified. the localization accuracy measure is defined for one and for multiple cameras too. the problem of adding a new camera to the system in order to improve the accuracy is formulated. the method for finding the optimal placement of this new camera is presented. Some features are enumerated which can be applied for getting an advanced method.
In the presented paper an analytically force overshoots-free approach is described for the execution of robotics interaction tasks involving a compliant (of unknown geometrical and mechanical properties) environment. ...
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ISBN:
(纸本)9789897581496
In the presented paper an analytically force overshoots-free approach is described for the execution of robotics interaction tasks involving a compliant (of unknown geometrical and mechanical properties) environment. Based on the impedance control, the aim of the work is to perform force-tracking applications avoiding force overshoots that may result in task failures. the developed algorithm shapes the equivalent stiffness and damping of the closed-loop manipulator to regulate the interaction dynamics deforming the impedance control set-point. the force-tracking performance are obtained defining the control gains analytically based on the estimation of the interacting environment stiffness (performed using an Extended Kalman Filter). the method has been validated in a probing task, showing the avoidance of force overshoots and the achieved target dynamic performance.
Unmanned aerial vehicles (UAV) equipped with a navigation system and an embedded camera can be used to estimate the position of a desired target. the relative position of the UAV along with knowledge of camera orienta...
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ISBN:
(纸本)9789897583049
Unmanned aerial vehicles (UAV) equipped with a navigation system and an embedded camera can be used to estimate the position of a desired target. the relative position of the UAV along with knowledge of camera orientation and imagery data can be used to produce bearing measurements that allow estimation of target position. the filter methods applied are prone to biases due to noisy measurements. Further noise may be encountered depending on the UAV trajectory for target localisation. this work presents the implementation of an Unscented Kalman Filter (UKF) to estimate the position of a target on the 3D cartesian plane within a small indoor scenario. A small UAV with a single board computer, equipped with a frontal camera and moving in an oval trajectory at a fixed height was employed. Such a trajectory enabled an experimental comparison of UAV simulation data with UAV real-time flight data for indoor conditions. Optitrack Motion system and the Robot Operative System (ROS) were used to retrieve the drone position and exchange information at high rates.
the Point Pair Features (PPF) method has been shown to be effective for pose estimation under clutter and occlusion. Our improved method mainly includes: (1) an approach for solving normal orientations of closed geome...
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ISBN:
(纸本)9781665449861
the Point Pair Features (PPF) method has been shown to be effective for pose estimation under clutter and occlusion. Our improved method mainly includes: (1) an approach for solving normal orientations of closed geometries based on Odd-even Rule;(2) an efficient downsampling approach by dividing a voxel grid into equivalent angle cells;(3) a verification step based on fitting points. the method is evaluated on real datasets of clutter and shows better performance as well as efficiency for 6D pose estimation compared to original PPF method.
Online and robust localization in a large scale outdoor environment is an essential component for self-driving vehicles. this paper addresses the theoretical and experimental development of a 6DOF localization approac...
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ISBN:
(纸本)9781479951994
Online and robust localization in a large scale outdoor environment is an essential component for self-driving vehicles. this paper addresses the theoretical and experimental development of a 6DOF localization approach with an online Unscented Rauch-Tung-Striebel (RTS) Smoother. this work focuses on the performance evaluation of the Unscented RTS smoother from a low-cost inertial sensor and consumer-grade Differential Global Positioning System (DGPS). the method is evaluated on a publicly available dataset (with centimetre accuracy benchmark) where we compare our results against the stand-alone Unscented Kalman filter (UKF) and an offline unscented RTS smoother. the extensive evaluation against the conventional approaches demonstrates the effectiveness of our approach, capable of providing accurate/online vehicle's localization information.
CREA robot is designed to climb up concrete walls. the robot uses the suction mechanism to provide adhesion and wheel mechanism for locomotion. Eleven chambers which are connected to one common reservoir are responsib...
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ISBN:
(纸本)9789897580406
CREA robot is designed to climb up concrete walls. the robot uses the suction mechanism to provide adhesion and wheel mechanism for locomotion. Eleven chambers which are connected to one common reservoir are responsible to produce adhesion force. A controller is developed to independently control each chamber while satisfying certain criteria on the safety of the robot. It is also designed to reach minimum friction between active inflatable seals and wall. In conclusion, the controller is able to successfully meet the conditions of stability, minimum friction and safety.
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