Advanced Materials Research Vols. 488-489

Abstract: This paper reports the design and simulation results of a novel underwater robot which can perform both fish-style and dolphin-style swimming. Locomotion modes of the robot include straight swimming, left/right turning, upward/downward swimming and rolling. The outstanding feature of the robot is that it can make a rapid change of its beating style simply by rotating the center of mass. Although it has a simple structure actuated by three RC-servo motors, the robot possesses great maneuverability, which is verified by computer simulation

Abstract: Dilution is a vital element in surfacing and depends on the difference in chemical composition between the weld and the parent metal, the welding process and the technique used. Metal surfacing is becoming the natural choice for reducing the consumption of expensive raw materials, processing cost and proper resource utilization. Mechanical as well as the metallurgical properties are greatly influenced by the degree of dilution. The advanced submerged arc welding (ASAW) process controls the response parameters independently and breaks the fixed relationship between the wire feed rate (W) and the welding current (I). A study was conducted to investigate the effect of process variables on the dilution during the process. The preheating of the electrode wire used in Submerged Arc Welding process (SAW) for surfacing application was done with the modification in the existing setup. Stainless steel 308L electrode wire was used on mild steel substrate to study the effect of preheating on the dilution. The results show that ASAW process controls and significantly reduces the percent dilution as compared with the conventional SAW process. ASAW process reduces the heat input, use of consumables and increased productivity, is the added advantages over the conventional process.

Abstract: Traditional lighting has many disadvantages, such as dispersed control, energy inefficacy, which could waste much of human and material resources. With people demands of controlling light source and saving energy, intelligent lighting become realistic with the help of RF and NC technologies. This paper designs an intelligent lighting control network using nRF24L01, and the network has set up in a lighting system experiment. This network make full use of the advantage of wireless sensor networks, it can be used in a variety of control systems to solve the problem of decentralized control. Compared with the traditional control mode, it would not only improve source utilization ratio, but also make better the lighting system management.

Abstract: An autonomous Mobile Robot (AMR) is a machine able to extract information from its environment and move in a meaningful and purposeful manner. Robot Navigation and Obstacle avoidance are the most important problems in mobile robots. In the past, a number of soft computing algorithms have been designed by many researchers for robot navigation problems but very few are actually implementable because they haven’t considered robot size as parameter. This paper presents software simulation and hardware implementation of navigation of a mobile robot avoiding obstacles and selecting optimal path in a static environment using evolution based Genetic algorithms with robot size as a parameter in fitness function.

Abstract: In order to raise position accuracy and stability in wafer transmission process, a tactile sensing system which can measure both deviation of wafer to manipulator and friction acting on wafer simultaneously is introduced. Analysis on kinetic model abstracted from sensing system is made, and following algorithms are applied: micro displacement is calculated through pressure values acting on different sensing units, and meanwhile friction is calculated from relative velocity between permanent magnet and inductance. Through simulation, indicators of sensing unit are established. This sensing system has the capacity of detecting deviation ranging 0-5 mm with resolution 0.05 mm and measure friction ranging 0-0.64 N. The results indicate that this sensing system meets the requirements in orthocenter deviation and friction measurement in wafer transmission process.

Abstract: The paper establishes an original computation formula for the flow rate of the fluid transported by a new type of rotating machine with profiled rotors; the theoretical characteristic diagram of the machine - flow rate versus machine speed - is built. The scheme of the test stand used for performing measurements needed in order to build the experimental diagram is presented. The variation of the volumetric efficiency of the working machine in function of the machine speed is finally described.

Abstract: In order to solve the spool sluggishness and jamming problem of a hydraulic proportional remote control valve that is encountered in the course of research and development for this valve. All the possible channels resulted in spool sluggishness and jamming are analyzed, and we should find the relative reasons from hydraulic spool sluggishness and jamming and mechanical spool sluggishness and jamming respectively. Through the relative improvement on the spool and experiment, the probability of spool sluggishness and jamming would be reduced largely.

Abstract: Model reference adaptive control is a major design method for controlling plants with uncertain parameters. The primary objective of this paper is to develop a new design approach for the model reference adaptive control of a single-input single-output linear time-invariant plant. The proposed method, called the “Model reference adaptive control using stacked identifiers, “uses a stacked identifier structure that is new to the field of adaptive control. The goal is to make the output of the plant asymptotically track the output of the first identifier, and then driving the output of the first identifier to track that of the second identifier, and so forth, up to the q-th identifier where q is the relative degree of the plant. Lastly, the output of the q-th identifier is forced to converge to that of the reference model. Simulation results shown our paper provides a new adaptive scheme which may give a better transient performance. No state measurement of the plant is required in our method. Since the resulting control systems are nonlinear and time-varying, the stability analysis of the overall system plays a central role in developing the theory.

Abstract: Online coordination of multiple robots working on a single workstation requires special attention. In these applications it is generally necessary that the robot arm follow a desired path in workspace so that it does not crash with any obstacle or the other robots. In this paper a two link planar robot crossing a rectangular obstacle is considered. The proposed idea is to define the relationship between obstacle's dimensions and the required joints trajectories parameters which allow the robot to reach its destination in the presence of an obstacle. First, the desired path for robot avoiding the obstacle is defined using a fourth degree polynomial. Corresponding robot joints trajectories are defined using a sinusoidal function with four parameters. Next, Design of Experiments (DOE) technique is utilized. Three levels for width and length of the obstacle are used as input and a full factorial DOE with nine experiments is defined. Instead of using the inverse kinematics, Particle Swarm Optimization (PSO) algorithm is used to obtain parameters of the robot joint sinusoidal functions. A second degree regression is used to obtain the relationship between each of the four sinusoidal function parameters and the obstacle dimensions. The obtained regression equations allow online changes to the trajectory as obstacle dimensions change. Four case studies, different obstacle dimensions, are simulated using the two link robot. The results show that using the obtained relationships the robot reaches its desired destination, with high accuracy, while avoiding the obstacles.

Abstract: Cantilevered beams can serve as a basic model for a number of structures used in various fields of industry, such as airplane wings, turbine blades and robotic manipulator arms.In this paper, the active vibration control of a smart cantilevered beam with a piezoelectric patch is studied. Additionally, the optimization of influential parameters of piezoelectric actuator for the purpose of vibration suppression is performed. Initially, the finite element modeling of the cantilevered beam and its piezoelectric patch is described and the implementation of a control system for vibration suppression is introduced. Transient response of the system under impact loading, with and without controller, is simulated using ANSYS. Taguchi’s design of experiments method is used to investigate the effect of five geometric parameters on the vibrational behavior of the system. It is shown that, optimal selection of levels for geometry of the piezoelectric actuator and sensor, can dramatically improve the dynamic response of the smart beam.