Force and impedance control for hydraulically driven hexapod robot walking on uneven terrain

A variety approach of multi-legged robot designs, especially on a large scale design with hydraulically driven actuators exist, but most of it still unsolved and used primitive techniques on control solutions. This made this area of research still far from demonstrating the scientific solutions, which is more towards developing and optimizing the algorithm, control technique and software engineering for practical locomotion (flexibility and reliability). Therefore in this thesis,the study is done to propose two categories of solution for statically stable and hydraulically driven hexapod robot, named COMET-IV, which are dynamic walking trajectory generation and force/impedance control implementation (during body start patching), in order to solve the stability problems (horizontal) that encountered when walking on extremely uneven terrains.Only three sensors are used for control feedback; potentiometers (each leg joint), pressure sensors (hydraulic cylinders) and attitude sensor (center of body). For dynamic walking trajectory generation, the fixed/determined of tripod walking trajectory is modified with force threshold-based, named as environment trailed trajectory (ETT),on each first step of foot during support phase (preliminary sensing uneven terrain surfaces). Moreover,the proposed dynamic trajectory generation is then upgraded with capability of omni-directional walking with a proposed center of body rotational-based method. The instability of using the ETT module alone and with proposed hybrid force/position control in the previous progress, during body patching on walking session is then solved using the proposed pull-back position-based force control (PPF). PPF controller is derived from the ETT module itself and supported by proposed compliant (switching) mechanism, logical attitude control and dynamic swing rising control. The limitation of PPF controller applied with ETT module for walking on uneven terrain contains extreme soft surface makes the study narrowed to the impedance control approaches as a replacement of PPF controller. Three new adaptive impedance controller are designed and proposed: Optimal single leg impedance control based on body inertia, Optimal center of mass—based impedance control based on body inertia and Single leg impedance control with self-tuning stiffness. To reduce the hard swinging/shaking of the robot's body in motion that arise after applying the proposed impedance controllers, fuzzy logic control via Takagaki-Sugeno-Kang (TSK) model is proposed to be cascaded on the input feedback of the controller.The study has verified the effectiveness of both categories of control unit (dynamic trajectory,force controller and impedance controllers) combination throughout several experiments of COMET-IV walking on uneven/unstructured terrains

The Effect of Dietary Supplements on the Development of Bombyx Mori L. Silkworms

We know that the silkworms consume leaves in large quantities. The scope of the research was their reaction to various additives for their food. Mulberry leaves spray-coated in several dietary supplements were administered starting with the 5th day of the 3rd instar. The substances used were flax (linseed) oil, hemp oil and 2.5% fat cow’s milk. The research was performed on four different silkworm hybrid strands. Each hybrid was separated in 4 lots, a control group and one for each of the three supplements. The preliminary conclusions of the research were that the best results were obtained with the 2.5% milk supplement, where we observed the highest individual mass and silk quantity compared to the other lots

Total Content of Polyphenols and Antioxidant Activity of Different Melliferous Plants

In this study polyphenols content and antioxidant activity of melliferous plants for the following: mint (Mentha pulegium), burdock (Arctium lappa), comfrey (Symphytum officinale), plantain (Pantago lanceolata), thyme (Thymus vulgaris), sage (Salvia officinalis), marigold (Calendula officinalis), small marshmallow (Althaea officinalis), echinacea (Echinaceea angustifolia) and black popular (Populus nigra) were investigated, using two different extraction methods. High content of polyphenols and flavones were extracted from Populus nigra, with an average of both extractions 23.14 mg GAE/g and 78.07 mg QE/g flavones. Among the studied plants, Arctium lappa registered the highest antioxidant activity (0.129 mmol Trolox/mL) in alcoholic extract and Echinaceea angustifolia with a value of 0.122 mmol Trolox/mL in aqueous extract. The lowest values were recorded for the antioxidant activity of Althaea officinalis (alcoholic extract) and Arctium lappa (aqueous extract). The results show that Arctium lappa, Echinaceea angustifolia and Populus nigra can be considered melliferous plants for their high biologically active compounds potential and bee products (honey and pollen) that having the composition of these plants will have high antioxidant and antibacterial properties

THE ASSESSMENT OF THE ANTIBACTERIAL ACTIVITY OF SOME PLANT EXTRACTS ON NORMAL AND PATHOGENIC MICROFLORA FROM MILK

This paper presents the evaluation of antibacterial activity of some plant alcoholic extracts over bacteria in milk as an alternative to current antibiotics. Tests were conducted on alcoholic extracts from sage (Salvia officinalis), two hop species Brewers Gold and Perle and two essential oils (rosemary - Rosmarinus officinalis and lavender - Lavandula angustifolia). The antibacterial susceptibility has been evaluated over 24 strains isolated from normal milk and mastitis milk, belonging to Staphylococcus, Vibrio, Serratia, Aeromonas and Bacillus genera. The obtained results show the best antibacterial effect with rosemary essential oil, having areas of inhibition as big as 28 mm, with an average of 16.4 mm. Weaker antimicrobial effect was obtained with alcoholic extract of sage where the average of inhibition diameters were 12.2 mm. Bacterial species isolated from mastitis were more sensitive to treatment with plant extracts compared with species isolated from normal milk. Among the tested bacteria, the strains from Staphylococcus type had the highest sensitivity, while Vibrio strains were more resistant. The results obtained open the prospect of using these herbal extracts as an alternative to the use of antibiotics in the treatment of mastitis and also aim at getting safer products from a microbiological point of view, with less antibiotic residues in milk