scholarly journals A three dimensional localiser for autonomous robot vehicles

Robotica ◽  
1995 ◽  
Vol 13 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Lindsay Kleeman
Keyword(s):  
Kalman Filter ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Autonomous Robot ◽  
Minimum Number ◽  
Position And Orientation ◽  
Filter Approach ◽  
And Performance ◽  
Performance Results ◽  
Orientation Determination

SummaryA novel design of a three dimensional localiser intended for autonomous robot vehicles is presented. A prototype is implemented in air using ultrasonic beacons at known positions, and can be adapted to underwater environments where it has important applications, such as deep sea maintenance, data collection and reconnaissance tasks. The paper presents the hardware design, algorithms for position and orientation determination (six degrees of freedom), and performance results of a laboratory prototype. Two approaches are discussed for position and orientation determination – (i) fast single measurement set techniques and (ii) computationally slower Kalman filter based techniques. The Kalman filter approach allows the incorporation of robot motion information, more accurate beacon modelling and the capability of processing data from more than four beacons, the minimum number required for localisation.

Design and Evaluation of Human–Machine Interface for NEXUS: A Custom Microassembly System

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Danming Wei ◽  
Mariah B. Hall ◽  
Andriy Sherehiy ◽  
Dan O. Popa
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Human Machine Interface ◽  
Mems Technology ◽  
Machine Interface ◽  
Micro Electromechanical System ◽  
Performance Results ◽  
Assembly Performance ◽  
Assembly Rate

Abstract Microassembly systems utilizing precision robotics have long been used for realizing three-dimensional microstructures such as microsystems and microrobots. Prior to assembly, microscale components are fabricated using micro-electromechanical-system (MEMS) technology. The microassembly system then directs a microgripper through a series of automated or human-controlled pick-and-place operations. In this paper, we describe a novel custom microassembly system, named NEXUS, that can be used to prototype MEMS microrobots. The NEXUS integrates multi-degrees-of-freedom (DOF) precision positioners, microscope computer vision, and microscale process tools such as a microgripper and vacuum tip. A semi-autonomous human–machine interface (HMI) was programmed to allow the operator to interact with the microassembly system. The NEXUS human–machine interface includes multiple functions, such as positioning, target detection, visual servoing, and inspection. The microassembly system's HMI was used by operators to assemble various three-dimensional microrobots such as the Solarpede, a novel light-powered stick-and-slip mobile microcrawler. Experimental results are reported in this paper to evaluate the system's semi-autonomous capabilities in terms of assembly rate and yield and compare them to purely teleoperated assembly performance. Results show that the semi-automated capabilities of the microassembly system's HMI offer a more consistent assembly rate of microrobot components and are less reliant on the operator's experience and skill.

Unscented Kalman filter approach to tracking a moving interfacial boundary in sedimentation processes using three-dimensional electrical impedance tomography

2009 ◽  
Vol 367 (1900) ◽  
pp. 3095-3120 ◽  
Author(s):  
Anil Kumar Khambampati ◽  
Ahmar Rashid ◽  
Umer Zeeshan Ijaz ◽  
Sin Kim ◽  
Manuchehr Soleimani ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Unscented Kalman Filter ◽  
Phase Interface ◽  
Three Dimensional ◽  
Measurement Model ◽  
Impedance Tomography ◽  
Filter Approach ◽  
Sedimentation Processes

The monitoring of solid–fluid suspensions under the influence of gravity is widely used in industrial processes. By considering sedimentation layers with different electrical properties, non-invasive methods such as electrical impedance tomography (EIT) can be used to estimate the settling curves and velocities. In recent EIT studies, the problem of estimating the locations of phase interfaces and phase conductivities has been treated as a nonlinear state estimation problem and the extended Kalman filter (EKF) has been successfully applied. However, the EKF is based on a Gaussian assumption and requires a linearized measurement model. The linearization (or derivation of the Jacobian) is possible when there are no discontinuities in the system. Furthermore, having a complex phase interface representation makes derivation of the Jacobian a tedious task. Therefore, in this paper, we explore the unscented Kalman filter (UKF) as an alternative approach for estimating phase interfaces and conductivities in sedimentation processes. The UKF uses a nonlinear measurement model and is therefore more accurate. In order to justify the proposed approach, extensive numerical experiments have been performed and a comparative analysis with the EKF is provided.

Performance Characteristics of Regenerative Flow Compressors for Natural Gas Compression Application

2005 ◽  
Vol 127 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Mukarrum Raheel ◽  
Abraham Engeda
Keyword(s):  
Mathematical Model ◽  
Natural Gas ◽  
Three Dimensional ◽  
Governing Equations ◽  
One Dimensional ◽  
Gas Compression ◽  
And Performance ◽  
Regenerative Flow ◽  
Performance Results ◽  
Channel Region

In this paper we discuss the application of regenerative flow compressors (RFC) for low-pressure natural gas compression required by microturbine systems. A brief overview of fundamentals and the hypothesis of the operation of RFC is presented. A mathematical model to describe the complex three-dimensional corkscrew flow pattern in RFC is discussed. Governing equations for the blade and channel region are developed. A one-dimensional (1-D) performance prediction code for RFC based on governing equations and loss models is developed and performance results are compared with experimental data on a multistage RFC. Excellent agreement between theoretical and experimental results is observed, thus validating the proposed mathematical model.

scholarly journals Light effects on circadian and homeostatic regulation: alertness increases independent of time awake

2020 ◽  
Author(s):  
R. Lok ◽  
T. Woelders ◽  
M.J. van Koningsveld ◽  
K. Oberman ◽  
S.G. Fuhler ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bright Light ◽  
Night Time ◽  
Free Running ◽  
Light Effects ◽  
Phase Progression ◽  
And Performance ◽  
Time Awake ◽  
Subjective Alertness ◽  
Performance Results

AbstractLight induced improvements in alertness are more prominent during night-time than during the day, indicating circadian regulation or wake duration related dependence. Relative contributions of both factors can be quantified using a forced desynchrony (FD) designs. Here we investigate alerting effects of light in a novel 4×18 hours FD protocol (5h sleep, 13h wake) under dim (6 mlux) and bright light (1159 mlux) conditions. Hourly saliva samples (melatonin and cortisol assessment) and 2-hourly test-sessions were used to assess effects of bright light on subjective and objective alertness (electroencephalography and performance). Results reveal (1) stable free-running cortisol rhythms with uniform phase progression under both light conditions, indicating that FD designs can be conducted under high intensity lighting, (2) subjective alerting effects of light depend on elapsed time awake, while (3) light consistently improves objective alertness independent of time awake. Three dimensional graphs reflecting light induced alertness improvements depending on wake duration related variation and circadian clock phase suggest that performance is improved during daytime, while subjective alertness remains unchanged. This suggests that light during office hours might be beneficial for performance, even though this may not be perceived as such.

Firm Standing for Legged Mobile Manipulators

2004 ◽  
Vol 16 (3) ◽  
pp. 312-318
Author(s):  
Takashi Tagawa ◽  
◽  
Yasumichi Aiyama ◽  
Hisashi Osumi ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Human Beings ◽  
Hand Force ◽  
Position And Orientation ◽  
Three Dimensional Space

A mobile manipulator generates external force on its hand when it works, making it unable to conduct work accurately because the robot becomes unstable, unlike human beings, who stand stably despite a large hand force acting on their hands. This uses redundant degrees of freedom (DOF) that freely change the body’s position and orientation even if legs are fixed. We focus on a legged robot as a part of locomotion and propose firm standing using a legged mobile manipulator that tolerates greater hand force while maintaining a stable working position. This report proposes firm standing, analyzes it on a two-dimensional vertical plane and in three-dimensional space, and details experiments that demonstrate its feasibility.

The Relation Between Financial Incentives, Motivation, and Performance

2017 ◽  
Vol 16 (2) ◽  
pp. 61-76 ◽  
Author(s):  
Anaïs Thibault Landry ◽  
Marylène Gagné ◽  
Jacques Forest ◽  
Sylvie Guerrero ◽  
Michel Séguin ◽  
...  
Keyword(s):  
Financial Incentives ◽  
Work Performance ◽  
Autonomous Motivation ◽  
Compensation Plans ◽  
Work Settings ◽  
Path Analyses ◽  
Three Samples ◽  
And Performance ◽  
Performance Results

Abstract. To this day, researchers are debating the adequacy of using financial incentives to bolster performance in work settings. Our goal was to contribute to current understanding by considering the moderating role of distributive justice in the relation between financial incentives, motivation, and performance. Based on self-determination theory, we hypothesized that when bonuses are fairly distributed, using financial incentives makes employees feel more competent and autonomous, which in turn fosters greater autonomous motivation and lower controlled motivation, and better work performance. Results from path analyses in three samples supported our hypotheses, suggesting that the effect of financial incentives is contextual, and that compensation plans using financial incentives and bonuses can be effective when properly managed.

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