Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 4 uppsatser.

Examensarbete. / Delrapport i FoU-projekt S 01-3284/08 "Skötsel av vegetation inom banområde"

Abstract Increasing efficiency is a necessary target for an industrial roaster nowadays. This thesis presents some studies on efficiency improvement in the zinc roasting process - process characterisation, control design, implementation and testing. The thesis focuses on the roaster, i.e. on research regarding the phenomena in the roaster furnace. By learning more about the roasting mechanism, particle size growth and dynamics of the furnace, new control implementations have been developed. More measurements, analyses and calculated variables have been added to give more information on the state of the furnace. New control variables have been introduced to give the operators more opportunities to set the conditions so that they are more suitable for the actual concentrate feed mixture. Equipment modifications have also been done. In this research, both laboratory and plant experiments have been performed together with thermodynamic evaluations and calculations. It has been necessary to make plant trials in order to obtain information about the impacts of different variables on the process. Only full-scale experiments give reliable results of the behaviour of an industrial furnace. The experiments with the roaster furnace have emphasised the study of both the metallurgy and the dynamics of the roasting process. The on-line calculated oxygen coefficient and its active control have proved important. The particle size distribution analysis of the furnace calcine has been shown to be a significant source of information for evaluating the state of the roasting furnace. The main target is to improve the economic performance. The key is to be able to be flexible in using different kinds of raw materials, because the main income is the treatment charge. The trend is that concentrates are becoming finer, which increases the challenges for roaster furnace control. The capability to use low-grade concentrates is also a major challenge and improves the economic result. Research and development on the boiler and mercury removal has also been part of this work for many reasons. Improved boiler performance and mercury removal gives more freedom in choosing concentrates and operating the roaster furnace. The approach has been the same as in the roaster furnace research and development work. Control improvements based on existing knowledge, such as fuzzy control systems for controlling the furnace temperature and mercury removal, did stabilize the process, but they did not solve all the problems regarding process stability. The research and development concept of this thesis has provided the extra knowledge needed for further improvement of process control. The results of the process characterisation have led to the implementation of a new and effective control strategy. The research and development carried out has improved performance in a number of ways: increased running time of the furnace and boiler, in-depth knowledge of roasting phenomena which led to new control methods and instructions for the operators, improved quality of sulphuric acid and a method to control its quality, measurements and analyses that give valuable information of the state of the process – all of which are now in use. In the future, the emphasis will be placed on the research and development of roaster furnace performance, which will be a great challenge. Control of the roaster furnace is the key to the economic success of the roasting process and more information about these phenomena is needed for improving and optimising control.

Motivated by challenges operators face with manual control tasks, including fatigue and workload management, this research explores the adoption of a semi-autonomous control method to improve work environment quality and task metrics in controlled situations. Building upon the success of Programming by Demonstration (PbD) for single-arm industrial robotic applications, we extend these techniques to dual-arm robotic control. We present a semi-autonomous approach allowing users to supervise tasks while delegating control to the system, alleviating stress and fatigue associated with manual control operations. This research compares manual and semi-autonomous control in a human-robot team, focusing quantitatively on user performance and qualitatively on trust in the system. Participants controlled a dual-arm robotic system from a remote cockpit, monitoring progress through a graphical user interface (GUI) and camera views. Semi-autonomous control employs PbD with selectable ’motion primitives’. Trials involved a modified pick-and-place task and results demonstrate a significantly higher success rate across all metrics with semi-autonomous control. This study highlights the applicability of PbD as a semi-autonomous control method in human-robot teams, reducing workload stress and enhancing task performance. Integrating sensors for dynamic environment analysis to create motion feedback mechanisms could further enhance user trust and system adaptability. Ultimately, this research suggests implementing semi-autonomous control for dual-arm robotic systems, offering faster onboarding for new operators and increased operational flexibility while minimizing user stress and fatigue.

No / Rosnecatrone 7 is a phytotoxic metabolite isolated from cultures of a virulent strain of the fungus Rosellinia necatrix. The compound is identified as 5-hydroxy-4-hydroxymethyl-1-(1-hydroxy-3-methylbut-2-enyl)-3-[(E)-propenyl]-7-oxabicyclo[4.1.0]hept-3-en-2-one by chemical and physical methods. The absolute configuration is determined

The thesis presents comparative study of modern control methods for regulating under-actuates systems. The classical pendulum on a cart system, a 2-DOF under-actuated system was utilized as a benchmark system for analyzing controllers' performances. The work includes analysis, controller design and swing-up control simulation for the following three methods: Nonlinear state-space control The mathematical model based on the Lie theoretic approach with nonlinear output injection was developed. The controller accomplishes both swing-up and stabilization of the pendulum. The feasibility of the implementation is limited due to physical constraints (length of the cart rail). Fuzzy logic control A Sugeno type fuzzy inference engine implementing the control strategy was built over the system fuzzy model. The simulations showed successful controller behavior but the generated system control input exhibited some non-smoothness that could cause increase on the actuator demand. Method of embedded artificial constraints (EAC). The analysis reveals dependence between the pendulum motion and the cart acceleration. Using this artificial constraint a state link was developed and the nonlinear control problem was reduced to a linear controller design. A stabilizing linear state-space controller has been developed and methods for arbitrary pole placement and optimal linear quadratic regulator design were compared. A reduced order current estimator for velocity estimation has been studied and implemented. A software client/server controller application running on a QNX Neutrino 6.1 platform was developed. The real-time experiments conducted with the EAC/linear state-space controller confirmed good swing-up and stabilization system performance.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 5 uppsatser.

Licentiatavhandling (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 2 uppsatser.

This thesis deals with the occurrence, biology and control of dangerous weeds on arable land. The thesis aims to process the selected weeds in stands of cultivated crops overview of the biology, extension and suggest regulatory measures for especially dangerous weeds on arable land as for example Elytrigia repens L., Cirsium arvense L. and other. For selected species were assayed determination germination of seeds and detection weight thousands of seeds.

Weeds currently represent a constant risk to the crop plants. They are able to either suppress the development of a crop plant in the initial period of its growth or to hinder and even make the harvest impossible due to its stand density at the end of the vegetative phase before the harvest. Perennial weeds rank among very noxious weeds. They are highly resistant and able to adapt to the used control measures. The character of the crop plants itself and the applied agronomic practices determine the occurrence of different weed species. For this reason, the question of how to deal with weeds still remains crucial. The diploma thesis is focused on the occurrence and the harmful effects of selected weeds in two Maize hybrids (Zea mays). The incidence of weeds and the effect of herbicides on those weeds were monitored within an experiment conducted on a small plot of land. The following weed plants occurred: Couch-grass (Elytrigia repens L.), Creeping thistle (Cirsium arvense L.), Barnyard grass (Echinochloa crus-galli L.), Scentless mayweed (Tripleurospermum inodorum L.), Goosegrass (Galium aparine L.) etc. The aim of the thesis is to expand knowledge of the use of different weed control methods in Maize. Recommendations on the use of those methods in agriculture shall be suggested.