The Development of a Semi-Autonomous Framework for Personal Assistant Robots - SRS Project

SRS is a European research project for building robust personal assistant robots using ROS (Robotic Operating System) and Care-O-bot (COB) 3 as the demonstration platform. A semi-autonomous framework has been developed in the project. It consists of an autonomous control structure and user interfaces that support the semi-autonomous operation. The control structure is divided into two parts. First, it has an automatic task planner, which initialises actions on the symbolic level. The planner produces proactive robotic behaviours based on updated semantic knowledge. Second, it has an action executive for coordination actions at the level of sensing and actuation. The executive produces reactive behaviours in well-defined domains. The two parts are integrated by fuzzy logic based symbolic grounding. As a whole, they represent the framework for autonomous control. Based on the framework, SRS user interfaces are integrated on top of COB's existing capabilities to enable robust fetch and carry in unstructured environments.

Optimization of Focused Wave Front Algorithm in Unknown Dynamic Environment for Multi-Robot Navigation

Robotics is a field which includes multiple disciplines such as environment mapping, localization, path planning, path execution, area exploration etc. Path planning is the elementary requirement for all the above mentioned diversified fields. This paper presents a new method for motion planning of mobile robots which carry forward the best features of Focused Wave Front and other wave front based path planners, at the same time optimizes the algorithm in terms of path length, energy consumption and memory requirements. This research introduces a method of choosing every next step in grid based environment and also proposes a backtracking procedure to minimize turns by means of identifying landmark points in the path. Further, the authors have enhanced the functionality of Focused Wave Front algorithm by applying it in uncertain dynamic environment. The proposed method is a combination of global and local path planning as well as online and offline navigation process. A new method based on bidirectional wave propagation along the walls of obstacle and wall following behavior is being proposed for avoiding uncertain static obstacles. Considering the criticalness of moving obstacles a colored safety zone is assumed to have around them and the robot is equipped with color sensitivity. Based on the particular color (red, green, yellow) that has sensed the robot will make intelligent decisions to avoid them. The simulation result reflects how the proposed method has efficiently and safely navigates a robot towards its destination by avoiding all known and unknown obstacles. Finally the algorithms are extended for multi-robot environment.

Integrated Sensing Techniques for Assistive Chairs

This paper presents a survey of the contemporary assistive chairs and on-chair sensing approaches of capturing sit-to-stand (STS) movement. Sitting in a chair and standing up from a seated position are activities of daily living (ADLs) performed by humans. However, older people often encounter difficulties with these activities. These difficulties may cause substantial decreasing of the elderly mobility, leading to inactive participation in social activities and increasing the risk of chronic diseases that may cause premature death. Therefore, assisting older people to overcome these difficulties has significance for their independent living. At present, the assistive devices can be allocated in terms of market available ones and experimental prototypes, both of which are discussed here. Afterwards, the authors cast more light on integrated sensing techniques that are currently used with experimental prototypes and create a taxonomy of sensing techniques. Following from this survey, a chair capable of delivering assistance-as-needed is proposed.

Elastic Translational Joint for Large Translation of Motion Using Spiral Structures

As micro- and nano-devices become smaller, the ability to manipulate them with highly accurate control is increasingly important as well. The design of a micro-joint is important for highly accurate movement. In this paper, the authors discuss a new micro translational joint based on an elastic-design concept for large, precise translational motion. Using the elastic deformation of spiral structures, the new translational joint is able to accomplish precise movements over long distances. Because the proposed translational joint is integrated, there is no gap and it is thus able to move without friction. Through finite element method (FEM) simulation, the proposed translational joint was estimated to have large, but still precise, translational motion. An experiment was conducted on the optical tweezer with the result showings that the proposed joint is also capable of large, precise translational movement at the micro scale. Therefore, it is expected that there will be many applications for which the proposed translational joint can be used for the precise manipulation of micro and nano-scale devices.

Automatized Decision Making for Autonomous Agents

Utility theory and the principle of maximising the expected utility have, within the multi-agent community, had a great influence on multi-agent based decision. Even though this principle is often useful when evaluating a decision situation it is virtually impossible, except in very artificial situations, to use the more basic decision rules with its unrealistically strong requirements for the input data, and other candidate methods must be considered instead. This article provides an overview and brings attention to some of the possibilities to utilize more elaborated decision methods, while still keeping the computational issues at a tractable level.

Rolling Prevention Mechanism for Underground Pipe Erosion Inspection Robot with a Real Time Vision System

Pipe inspection is one of the areas that have attracted high research interest for robot applications especially in oil and chemical industry and civil engineering. Robot body rolling while it travels within a pipe has been a problem for accurately collecting inspection data. Under certain circumstances where vision systems have to be employed, robot body rolling may cause vision inspection data to have little value as it is difficult to know where exactly the camera was looking at. This paper proposes an anti-rolling mechanism to hold consistent camera orientation. By changing the position angle of the robot legs, the mechanism is able to adjust the resistance to rolling within a pipe, therefore preventing robot rolling happening. The design makes use of the friction force caused by the gravity force of the robot to prevent the robot body rolling. The design analysis quantifies the effect of pipe radius, robot weight, payload, and payload offset distance in robot rolling. A test model was built based on the design concept. The experimental results obtained from the test model match the predication of the computational analysis. A real time vision system has been developed using FPGA and the algorithm of the structured laser light stripe configuration in the context of pipe inspection. The real-time hardware implementation of the algorithms on the robot itself removes the need to transmit raw video data back to an operator.

Computing Nash Equilibria in Non-Cooperative Games

Game Theory has recently drawn attention in new fields which go from algorithmic mechanism design to cybernetics. However, a fundamental problem to solve for effectively applying Game Theory in real word applications is the definition of well-founded solution concepts of a game and the design of efficient algorithms for their computation. A widely accepted solution concept for games in which any cooperation among the players must be self-enforcing (non-cooperative games) is represented by the Nash equilibrium. However, even in the two players case, the best algorithm known for computing Nash equilibria has an exponential worst-case running time; furthermore, if the computation of equilibria with simple additional properties is required, the problem becomes NP-hard. The paper aims to provide a solution for efficiently computing the Nash equilibria of a game as the result of the evolution of a system composed by interacting agents playing the game.

A Robot for Cell Injection

This work deals with modelling and experimenting of a compliant serial-parallel robot. Using Pseudo-Rigid-Body Modelling (PRBM) of elastic structures, a kinematics and stiffness model of a serial-parallel structure has been built. Several approaches for pre-tensioning of a parallel structure with elastic joints were developed in order to eliminate backlashes and improve the performance of its actuators. In this work a robot is designed to inject biological cells with size in the range of 10-30µm. The approaches used for pre-tensioning of the robot have been analysed and subjected to numerical evaluation. Assessing the mechanical parameters of the tensed manipulator has been performed using the following methods: PRBM and Finite Element Analysis (FEA). An experimental set-up for testing a robot prototype has been developed, using an optical system and correlation technique for digital image processing. The experimental results obtained are compared to data received from the numerical experiment.

SensFloor® and NaviFloor®

The following chapter describes two systems, which both are perfect examples for ambient intelligence: sensor electronics, which is invisibly integrated into the floor. The first system comprises active sensors with high spatial resolution. It is able to detect people walking across the floor and recognizes peoples' location and movement behaviour. While the main application domains are Ambient Assisted Living (AAL), health care, security systems and home automation, several robotics applications are possible and have been investigated already. The second system serves for localizing moving objects such as robots, wheelchairs or hospital beds by means of passive RFID tags in the floor and an active RFID reader attached to the moving object. In the following, we describe the technical details of the two systems and robotics applications, which have already been realized or are under development.

Experimental System Identification, Feed-Forward Control, and Hysteresis Compensation of a 2-DOF Mechanism

Most of the micro/nano manipulation mechanisms and systems are commonly based on flexure-based monolithic structures, and are generally driven by piezoelectric actuators. In the presented work, experimental system identification, 1-DOF trajectory tracking with feed-forward control, and hysteresis compensation are investigated. An experimental research facility with laser interferometry-based sensing and measurement technique is established. System identification experiments were performed on a 2-DOF flexure-based mechanism to investigate its dynamics. The system identification procedure, experimental design, data acquisition, analysis and validation of the identified system are presented in details. A linear sine swept signal is applied to the system as an input and the corresponding response of the system is measured with laser interferometry-based sensing and measurement technique. The experimental results are used to evaluate the transfer function and the first natural frequency of the system in the X and Y axes. Experimental validation data is used to verify the accuracy of the identified model. Further, a feed-forward controller is established to track a 1-DOF smooth multiple-frequency trajectory. For hysteresis compensation, inverse PI (Prandtl–Ishlinskii) model is derived from classical PI model. The parameters of the inverse PI model is estimated and validated with the experimental data. Finally, inverse PI model is directly adopted as a feed-forward controller for hysteresis compensation of piezoelectric actuators.