Design and Trajectory Planning of Bipedal Walking Robot with Minimum Sufficient Actuation System

This paper presents a new type of mechanism and trajectory planning strategy for bipedal walking robot. The newly designed mechanism is able to improve the performance of bipedal walking robot in terms of energy efficiency and weight reduction by utilizing minimum number of actuators. The usage of parallelogram mechanism eliminates the needs of having an extra actuator at the knee joint. This mechanism works together with the joint space trajectory planning in order to realize straight legged walking which cannot be achieved by conventional inverse kinematics trajectory planning due to the singularity. The effectiveness of the proposed strategy is confirmed by computer simulation results

Acoustic and mechanical properties of luffa fiber-reinforced biocomposites

This chapter presents an overview of acoustic and mechanical behaviors of luffa fiber reinforced biocomposites. A growing number of studies are examining the composites of biodegradable fibers such as flax, hemp, kenaf and luffa due to the adverse effects of chemical materials on nature. The low cost and superior acoustic and acceptable mechanical properties of biocomposites make them very attractive for practical applications such as sound and vibration isolation. However, the acoustic and mechanical characteristics of biocomposites and their dynamic behaviors should be fully determined before considering them for practical applications. In this chapter, acoustic properties, such as sound absorption and transmission loss, and mechanical properties, such as damping and elasticity of luffa fiber reinforced composites, are presented. The variations in acoustic and mechanical properties due to different samples and manufacturing process are explored.WOS:000532438200017Scopus - Affiliation ID: 60105072Book Citation Index- ScienceArticle; Book ChapterOcak2019YÖK - 2018-1

Reinforced Oil Palm Fiber Epoxy Composites: An Investigation on Chemical Treatment of Fibers on Acoustical, Morphological, Mechanical and Spectral Properties

Oil palm fibers are plentifully unused waste types of cellulose fibers. It is extensively being wasted in modern agriculture and industries because of the limited research and knowledge on the use and functionality of oil palm fibers in certain sectors and products. Throughout this research, studies and examinations conducted to investigate the developments of reinforced untreated and treated oil palm fiber epoxy composites. Then, the effects of alkaline treatment on the fiber structure being analyzed. Lastly, based on the results obtained, the effects on the acoustical, morphological, mechanical, and spectral properties being investigated according to specific tests and standards

Dielectric Properties of Lignocellulosic Fibers Reinforced Polymer Composites: Effect of Fiber Loading and Alkaline Treatment

This research work focus on comparative studies of dielectric properties such as the dielectric constant, the dissipation and loss factor of four different types of composites made of lignocellulosic fibers with respect of fiber loading and alkali treatment. It has been observed that the dielectric constant, dissipation factor and loss factor progressively increases with increase in fiber loading and decreases with an increase in frequency. The dielectric properties of sisal/poly-lactic acid composites show higher values compared with other composites. This is due to the characteristics of lignocellulosic contents in the sisal fibers. The dielectric constant values were lower for fibers subjected to alkaline treatment

Design and trajectory planning of bipedal walking robot with minimum sufficient actuation system

This paper presents a new type of mechanism and trajectory planning strategy for bipedal walking robot. The newly designed mechanism is able to improve the performance of bipedal walking robot in terms of energy efficiency and weight reduction by utilizing minimum number of actuators. The usage of parallelogram mechanism eliminates the needs of having an extra actuator at the knee joint. This mechanism works together with the joint space trajectory planning in order to realize straight legged walking which cannot be achieved by conventional inverse kinematics trajectory planning due to the singularity. The effectiveness of the proposed strategy is confirmed by computer simulation results

Potential of Borneo Acacia wood in fully biodegradable bio-composites' commercial production and application

This review paper explores the potential of commercial production and application of Acacia wood—polylactic acid (PLA), and Acacia wood—polyhydroxyalkanoates (PHA) bio-composites. The factors affecting the mechanical and physical properties of these materials were identified and deliberated. It was found that Acacia wood has the prospective to be efficiently produced and used in Borneo. It can be used in a variety of applications, including but not limited to: fire breaker, timber resource, furniture production, soil re-conditioning, and as reinforced materials. Since, today, there is heightened awareness regarding sustainability, manufacturers are driven towards producing completely biodegradable products that are created using PLA and PHA bio-composites. This review provides an overview on the performance of the existing composites and bio-composites, and their implementation and utilization, while focusing on the Borneo region

An investigation of sound absorption coefficient on sisal fiber poly lactic acid bio-composites

In this research, the mechanical, acoustical, thermal, morphological, and infrared spectral properties of untreated, heat and alkaline-treated sisal fiber-reinforced poly-lactic-acid bio-composites were analyzed. The bio-composite samples were fabricated using a hot press molding machine. The properties mentioned above were evaluated and compared with heat-treated and alkaline-treated sisal fibers. Composites with heat-treated sisal fibers were found to exhibit the best mechanical properties. Thermo-gravimetric analysis (TGA) was conducted to study the thermal degradation of the bio-composite samples. It was discovered that the PLA-sisal composites with optimal heat-treated at 160°C and alkaline-treated fibers possess good thermal stability as compared with untreated fiber. The results indicated that the composites prepared with 30wt % of sisal had the highest sound absorption as compared with other composites. Evidence of the successful reaction of sodium hydroxide and heat treatment of the sisal fibers was provided by the infrared spectrum and implied by decreased bands at certain wavenumbers. Observations based on scanning electron microscopy of the fracture surface of the composites showed the effect of alkaline and heat treatment on the fiber surface and improved fiber-matrix adhesion