Robot Excitation Trajectories for Dynamic Parameter Estimation using Optimized B-Splines

In this paper we adressed the problem of finding exciting trajectories for the identification of manipulator link inertia parameters. This can be formulated as a constraint nonlinear optimization problem. The new approach in the presented method is the parameterization of the trajectories with optimized B-splines. Experiments are carried out on a 7 joint Light-Weight robot with torque sensoring in each joint. Thus, unmodeled joint friction and noisy motor current measurements must not be taken into account. The estimated dynamic model is verified on a different validation trajectory. The results show a clear improvement of the estimated dynamic model compared to a CAD-valued model

Modeling and Grey-box Identification of a Robot Manipulator

Modeling and parameter identification of the main three of an idustrial robot of the type ABB IRB 2000 is considered. This Master thesis has been done at the Department of Automatic Control, Lund Institute of Technology working with a real robot located in the Robotics Laboratory. The model has been bult using the simulation software called Dymola (Dynamic Modeling laboratory), and the parameter identification has been performed with some tools included in the same software. The procedures requested in order to carry out the modeling and the parameter calibration are explained in detail, and finally a short description about the control desig in Dymola is done

Estimation of objects’ inertial parameters, and their usage in robot grasping and manipulation

The subject of this thesis is the estimation of an object's inertial parameters by a robotic arm, and the exploitation of those parameters in the design of efficient manipulation criteria. The inertial parameters of objects describe the resistance of the object to an applied force, and dictate its motion. Research has shown that humans intuitively exploit them for their everyday manipulations. As humans are very capable of performing efficient manipulations, it is natural that robots should use the inertial parameters as well. Additionally, as the inertial parameters are not straightforward to calculate, there is the need for development of methods that can estimate them online. This thesis focuses on two directions, developing novel methods so that robots can accurately estimate the inertial parameters of an object, as well as developing manipulation criteria that can make robot task completion more efficient. The relevant literature is gathered, categorised and analytically described, and the innovation gaps are identified. The thesis offers novel research solutions on the problem of estimation of the inertial parameters with minimal robot interaction. The paradigm is shifted from the existing literature, and a data-driven estimation algorithm is introduced, that achieves accurate results with both simulated and real data. Additionally, the presented research is offering novel manipulation criteria that are affected by the object's inertial parameters. The results suggest that knowledge of the inertial parameters can make the robot tasks more power-efficient and safe to their surroundings. The core methodology is shown to be versatile to the robotic platform. Though most experiments are performed on a terrestrial robot, a numerical example is also shown for a space robot. The results of the thesis suggest that the developed methods can be used in various environments, with the most suitable being extreme environments where accuracy, efficiency and autonomy is required

Development of a real-time ultrasonic sensing system for automated and robotic welding

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The implementation of robotic technology into welding processes is made difficult by the inherent process variables of part location, fit up, orientation and repeatability. Considering these aspects, to ensure weld reproducibility consistency and quality, advanced adaptive control techniques are essential. These involve not only the development of adequate sensors for seam tracking and joint recognition but also developments of overall machines with a level of artificial intelligence sufficient for automated welding. The development of such a prototype system which utilizes a manipulator arm, ultrasonic sensors and a transistorised welding power source is outlined. This system incorporates three essential aspects. It locates and tracks the welding seam ensuring correct positioning of the welding head relatively to the joint preparation. Additionally, it monitors the joint profile of the molten weld pool and modifies the relevant heat input parameters ensuring consistent penetration, joint filling and acceptable weld bead shape. Finally, it makes use of both the above information to reconstruct three-dimensional images of the weld pool silhouettes providing in-process inspection capabilities of the welded joints. Welding process control strategies have been incorporated into the system based on quantitative relationships between input parameters and weld bead shape configuration allowing real-time decisions to be made during the process of welding, without the need for operation intervention.British Technology Group (BTG

Oceanographic surveys with autonomous underwater vehicles : performance metrics and survey design

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1998.Includes bibliographical references (p. 127-134).by Jeffrey Scott Willcox.M.S

The role of computer-aided design in the learning of practical 3D-descriptive geometry: a case study

There are a number of problems surrounding the teaching of practical 3-D descriptive geometry to children in secondary education, notably the difficulty pupils have with visualising an object's form from orthographic views, and the interpretation of an object's geometric attributes into the descriptive geometry representation. The purpose of the current research is to evaluate the use of computer-aided design in this area of the curriculum and is based upon work undertaken in a North London comprehensive school. The school and its context is described and evaluated. Theories of child development and educational psychology of relevance to the study are reviewed, notably the work of Piaget, Bryant, Gagne, and Freeman. The history and nature of 3-D descriptive geometry is reviewed in practice and in education, with special reference to various methods employed in instruction. Dr. J. Vince's PICASO SYSTEM of computer subroutines and functions written in FORTRAN for graphic applications is explained as a means of teaching the subject, with special reference to the researcher's own instructional material and computer programs. The use and effectiveness of these teaching materials are related and evaluated in the light of students' performance and results. The research concludes that the special benefits of computer graphics in this field are: the economic production of appropriate didactic material under the direct control of the teacher, increased pupil motivation due to the use of better illustration and the interest generated by computer-aided design project work. and an opportunity to employ analytic geometry to support learning. Its limitations include: the high cost of the computer and peripheral devices, and the lack of a facility for modelling objects by the removal of solid volumes in the existing software. Further research is recommended in the areas of computer graphics, descriptive geometry, and psychology

Proceedings of the 6th Annual Summer Conference: NASA/USRA University Advanced Design Program

The NASA/USRA University Advanced Design Program is a unique program that brings together NASA engineers, students, and faculty from United States engineering schools by integrating current and future NASA space/aeronautics engineering design projects into the university curriculum. The Program was conceived in the fall of 1984 as a pilot project to foster engineering design education in the universities and to supplement NASA's in-house efforts in advanced planning for space and aeronautics design. Nine universities and five NASA centers participated in the first year of the pilot project. The study topics cover a broad range of potential space and aeronautics projects that could be undertaken during a 20 to 30 year period beginning with the deployment of the Space Station Freedom scheduled for the mid-1990s. Both manned and unmanned endeavors are embraced, and the systems approach to the design problem is emphasized

Fourth NASA Workshop on Computational Control of Flexible Aerospace Systems, part 2

A collection of papers presented at the Fourth NASA Workshop on Computational Control of Flexible Aerospace Systems is given. The papers address modeling, systems identification, and control of flexible aircraft, spacecraft and robotic systems

NASA Aircraft Controls Research, 1983

The workshop consisted of 24 technical presentations on various aspects of aircraft controls, ranging from the theoretical development of control laws to the evaluation of new controls technology in flight test vehicles. A special report on the status of foreign aircraft technology and a panel session with seven representatives from organizations which use aircraft controls technology were also included. The controls research needs and opportunities for the future as well as the role envisioned for NASA in that research were addressed. Input from the panel and response to the workshop presentations will be used by NASA in developing future programs

Pilot study for subgroup classification for autism spectrum disorder based on dysmorphology and physical measurements in Chinese children

Poster Sessions: 157 - Comorbid Medical Conditions: abstract 157.058 58BACKGROUND: Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder affecting individuals along a continuum of severity in communication, social interaction and behaviour. The impact of ASD significantly varies amongst individuals, and the cause of ASD can originate broadly between genetic and environmental factors. Objectives: Previous ASD researches indicate that early identification combined with a targeted treatment plan involving behavioural interventions and multidisciplinary therapies can provide substantial improvement for ASD patients. Currently there is no cure for ASD, and the clinical variability and uncertainty of the disorder still remains. Hence, the search to unravel heterogeneity within ASD by subgroup classification may provide clinicians with a better understanding of ASD and to work towards a more definitive course of action. METHODS: In this study, a norm of physical measurements including height, weight, head circumference, ear length, outer and inner canthi, interpupillary distance, philtrum, hand and foot length was collected from 658 Typical Developing (TD) Chinese children aged 1 to 7 years (mean age of 4.19 years). The norm collected was compared against 80 ASD Chinese children aged 1 to 12 years (mean age of 4.36 years). We then further attempted to find subgroups within ASD based on identifying physical abnormalities; individuals were classified as (non) dysmorphic with the Autism Dysmorphology Measure (ADM) from physical examinations of 12 body regions. RESULTS: Our results show that there were significant differences between ASD and TD children for measurements in: head circumference (p=0.009), outer (p=0.021) and inner (p=0.021) canthus, philtrum length (p=0.003), right (p=0.023) and left (p=0.20) foot length. Within the 80 ASD patients, 37(46%) were classified as dysmorphic (p=0.00). CONCLUSIONS: This study attempts to identify subgroups within ASD based on physical measurements and dysmorphology examinations. The information from this study seeks to benefit ASD community by identifying possible subtypes of ASD in Chinese population; in seek for a more definitive diagnosis, referral and treatment plan.published_or_final_versio