Aarne Halme

Motion control of a spherical mobile robot

The paper deals with dynamics and control of a special type of mobile robot designed to act as a small platform to carry sensing devices or actuators in an environment where stability of the platform is critical, like in surveying unstructured hostile industrial environment exploring other planets, or simply being a part of a human place, like office or home, which has not been designed for mobile machines. The spherical construction offers extraordinary motion properties in cases where turning over or falling down are risks for the robot to continue its motion. Also it has full capability to recover from collisions with obstacles or another robots traveling in the environment.

Modelling of a microbial fuel cell process

SummaryAn electrochemical model for a microbial fuel cell process is proposed here. The model was set up on the basis of the experimental results and analysis of biochemical and electrochemical processes. Simulation of the process shows that the model describes the process reasonably well. The analysis of model simulation illustrates how the current output depends on the substrate concentration, mediator concentration and other main variables. The relationship between the current output and over-voltage is revealed from the modelling study.

Needs and solutions - home automation and service robots for the elderly and disabled

Numerous studies in the field of service robotics for elderly and disabled have been done. However, the overall user needs are rarely deeply considered. This work surveys the needs and challenges for assisted living at home for the elderly and disabled. Automation technology solutions for today and for the future to help the people to live better, safer and longer are researched. This work is part of future senior living-assistive automation-project. This project is shortly described. Research consists of three phases. In questionnaire-study phase opinions and needs for home automation and home robotics are analyzed. Interview-study phase includes interviews with different specialists, the elderly and disabled themselves, and excursions to care houses and other related institutions. Literature-study reveals user needs as well, but it concentrates more on solutions than the other phases. Multiple needs and solutions were found. They have been discussed and the results are presented in an organized table.

Moving Eye - Interactive Telepresence Over Internet with a Ball Shaped Mobile Robot

Abstract This paper describes a robotic and automation system presently under development for studying home automation and indoor robotic technologies as well as new service scenarios based on these technologies. The system consists of remote users, a home automation server, home automation equipment and a ball shaped mobile robot called Rollo. A remote user connects to the server from the Internet to interact with the robot by using an augmented reality user interface. The Rollo robot, its behaviour and functions in the system are discussed- Utilizing the system for both educational purposes and to develop a remote home aid system is discussed.

Positioning an autonomous off-road vehicle by using fused DGPS and inertial navigation

This paper deals with a positioning system for an autonomous vehicle ARSKA. Localization of the vehicle is based on fusion of internal dead reckoning navigation and periodic absolute position measurements. Fusion is performed by using a Kalman-type filtering technique. A similar kind of approach is used in correcting the heading measurement. This is important because the position error is mostly the result of the accumulated heading error. The resulting accuracy depends on the accuracy of the dead reckoning estimation and on the accuracy and frequency of the absolute position measurement. As an absolute position measurement system, several alternatives can be used. Two different systems have been used with the vehicle: an external optical measurement device, tachymeter, and different combinations of DGPS. A real guarding application will be discussed in the paper.

WorkPartner: Interactive Human-Like Service Robot for Outdoor Applications

WorkPartner is the prototype of a lightweight human-like mobile service robot designed to work interactively with humans in an outdoor environment. The tasks are similar to those a human can do and the robot may replace or work together with him/her. Mobility is based on a hybrid system, which combines the benefits of both legs and wheels to provide good terrain negotiating capability and large velocity range on variable ground. The robot is powered by a hybrid power system with electrical actuating and energy storage in the form of gasoline. The robot is equipped with a human-like two-hand manipulator. The long-term goal is to develop an adaptive and learning robot, which can carry different tools and work interactively with humans. The user or operator can be physically present on the same site as the robot and communicate with it by using speech and gestures, or he can use telepresence from a distant place and communicate via the Internet. In each case, communication takes place via a new type of user interface based on multimedia and cognition. In this paper we describe the mechatronic structure, the functional subsystems and motion control principles of the robot, as well as discuss the challenges of the development project.

3-D mapping of natural environments with trees by means of mobile perception

In this paper, a method of generating a three-dimensional (3-D) geometric model for large-scale natural environments with trees is presented. The environment mapping method, which uses range images as measurement data, consists of three main phases. First, geometric feature objects are extracted from each of the range images. Second, the relative coordinate transformations (i.e., registrations) between the sensor viewpoint locations, where the range data are measured, are computed. Third, an integrated map is formed by transforming the submap data into a common frame of reference. Tree trunks visible in the range images are modeled with cylinder segments and utilized as reference features for registration computation. The final integrated 3-D model consists of the cylinder segments representing the visible sections of the tree trunks, as well as of the ground elevation data. The constructed environment map can be utilized as, for example, a virtual task environment for outdoor robotic machines such as new-generation forest working machines or service robots.

Personal navigation system

This paper presents a human dead-reckoning system for beaconless indoor positioning. The system is based on traditional dead-reckoning sensors like compass, gyro, and accelerometers. Due to the difficult kinematics of a human, there are no ready solutions for the odometry. This problem is solved by using a self-made stride length measurement unit and laser odometry. All the sensors are integrated to a complete system including sensor fusion. The functionality of the integrated system is verified with tests in an office environment. Finally the test results are analyzed.

Functional state modelling approach for bioprocesses: local models for aerobic yeast growth processes

Abstract The functional state of a process is a novel concept which helps in monitoring and control of complex processes such as bioprocesses. The concept was introduced originally by Halme. The main idea is to use a two-level hierarchy where on the top level the process is divided into macrostates, called functional states, according to behavioural equivalence. In a functional state, the process is described by a conventional type of model which is valid in this functional state — called the local model. To illustrate further the concept of functional state in fermentation processes, experimental data and simulations of an aerobic fed-batch bakers yeast fermentation are presented. It is shown how this process can be divided into functional states by considering the cell metabolism in more detail, how the local models can be obtained, and how the functional states of a fed-batch bakers yeast fermentation and recognized on-line. By simulation and comparing the results to experimental data, it is further shown how the concept works in practice. The results are also used to demonstrate an optimal substrate feed control policy.

Modeling of Chromatographic Separation Process with Wiener-MLP representation

Abstract Dynamic input–output-models have been identified for columns of an industrial sequential ion-exclusive chromatographic separation unit. Models are aimed at describing motion and form transformation of the fronts of different substances in the columns so that changes in “limit cycles” dynamics and drifts to undesired disturbed states could be observed on-line with model based simulations. The model structure has been innovated on the basis of classical Wiener representation, in which nonlinear dynamic system is described with a combination of linear Laguerre dynamics and static nonlinear mapping. The static mapping is realized here with MLP-type neural network. A separate delay model is needed for describing the movement of the front. The delay time adapts on variations of the process flow rate. Form transformation of the front is described with a dispersion model, which is smoother type Wiener-MLP model. Forward and backward Laguerre presentations are calculated with Laguerre filters. These Laguerre presentations are mapped to the output with a neural network. Dynamics of “salt” and two important compounds have been modeled on the basis of analyzed samples, which were taken in a factory experiment during normal production. A priori information about the process dynamics can be included in the dispersion model by choosing a suitable Laguerre parameter, but otherwise representativeness of the identification data determines validity of the model.