Design of a Francis Turbine for a Small Hydro Power Project in Turkey

Many hydro power plants, both in small and large scales, are being constructed in Turkey. The total potential of these projects reach to 216 billion kWh of feasible energy. However a method was not yet developed for the design of hydraulic machinery equipment in Turkey. In order to accomplish the hydraulic turbine design without any prior information than the design parameters of the hydraulic project, a methodology is developed. This methodology involves the use of computational tools and it is applied for small hydro projects. This methodology is a parametric design-optimization procedure which consists of parametric geometry modeling, computational fluid dynamics analysis and structural verification.

First Test Results of a Haptic Tele-Operation System to Enhance Stability of Telescopic Handlers

According to a recent report of ILO (International Labour Organization), more than two million people die or loose the working capability every year because of accidents or work-related diseases. A large portion of these accidents are related to the execution of motion and transportation tasks involving heavy duty machines. The insufficient degree of interaction between the human operator and the machine may be regarded as one of the major causes of this phenomenon. The main goal of the tele-operation system presented in this paper is to both preserving slave (machine) stability, by reducing the inputs of slave actuators when certain unsafe working conditions occur, and improving the level of interaction at master (operator) side. Different control schemes are proposed in the paper, including several combinations of master and slave control strategies. The effectiveness of the algorithms is analyzed by presenting some experimental results, based on the use of a two degrees-of-freedom force feedback input device (with one active actuator and one passive stiff joint) coupled with a simulator of a telescopic handler.

Gain Scheduling Fuzzy Sliding Mode Strategy for Robotic Motion Control

A Mitsubishi Movemaster RV-M2 robotic system control system is retrofitted into system-on-programmable-chip (SOPC) control structure. The software embedded in Altera Nios II field programmable gate array (FPGA) micro processor has the functions of using UART to communicate with PC, robotic inverse kinematics calculation, and robotic motion control. The digital hardware circuits with encoder decoding, limit switch detecting, pulse width modulation (PWM) generating functions are designed by using Verilog language. Since the robotic dynamics has complicate nonlinear behavior, it is impossible to design a MIMO model-based controller on micro-processor. Here a novel model-free fuzzy sliding mode control with gain scheduling strategy is developed to design the robotic joint controller. This fuzzy controller is easy to implement with 1D fuzzy control rule and less trial-and-error parameters searching work. The experimental results show that this intelligent controller can achieve quick transient response and precise steady state accuracy for industrial applications.

A New Sheet Die Design Methodology to Eliminate Scrap Shedding Problems During Mass Production

Manufacturing companies need to improve their production technology with improved dimensional accuracy at lower cost in order to manufacture sheet metal based products. Scrap shedding is an issue that should be examined at the cutting and sheet metal forming operations. In order to extend the life cycle of the cutting moulds, scrap shedding should be identified. When scrap shedding has not been taken into consideration, scraps have accumulated in the moulds reducing the production quality and causing deformation of the mould, increasing the production cost by obligating to perform extra transactions. This study becomes more focused upon the analysis of scrap shedding. In order to simulate the scrap shedding LS-Dyna and Pam Stamp software have been used. For examining of the scrap shedding an automotive part was chosen. In order to realize scrap shedding having any problems, new improvements have been suggested. Design of Experiments techniques which provide important advantages to engineering studies have been examined. By means of experimental design techniques the scrap shedding design process was also added to the classical mold design approach via a less quantities of simulations.

Stiffness Analysis of a Spatial Parallel Mechanism With Flexible Moving Platform

In this paper, stiffness analysis of a 3-DOF spatial, 3-PSP type, parallel manipulator is investigated. Most previous stiffness analysis studies of parallel manipulators are performed using lumped model as well as assuming a rigid moving platform. In this paper, unlike traditional stiffness analysis, the moving platform is assumed to be flexible. Additionally, a continuous method is used for obtaining mathematical model of the manipulator stiffness matrix. This method is based on strain energy and Castigliano’s theorem [1]. For this purpose, first we solve inverse kinematics problem then We must find relationship between the applied external torques on the moving platform and the resultant joints forces. Next, strain energy moving platform is calculated. Strain energy of this element is calculated using force analysis and inverse kinematics problem. Finally, a FEM model is generated and used to simulate the physical structure. Simulation results are compared with the analytical model.

Study on Crashworthiness Characteristics of Several Concentric Thin Wall Tubes

There is a growing interest in the use of thin-wall structures as a means of absorbing the kinetic energy of a moving body. Multi-layered thin-wall structures are more efficient and lighter than thick-wall structures, and show better crashworthiness characteristics. In this task, several concentric aluminum thin wall tubes as energy absorber under axial and oblique loading are studied and optimum combination of these tubes is presented. The weight of the tubes is optimized while crashworthiness of tubes is not compromised. The commercial finite element program LS-DYNA that offers non-linear dynamic simulation capabilities was used in this study.

Construction of a Rational Tire Model for High Fidelity Vehicle Dynamics Simulation Under Extreme Driving and Environmental Conditions

In this paper, a control oriented rational tire model is developed and incorporated in a two-track vehicle dynamics model for the prospective design of vehicle dynamics controllers. The tire model proposed in this paper is an enhancement over previous rational models which have taken into account only the peaking and saturation behavior disregarding all other force generation characteristics. Simulation results have been conducted to compare the dynamics of a vehicle model equipped with a Magic Formula tire model, a rational tire model available in the literature and the present rational tire model. It has been observed that the proposed tire model results in vehicle responses that closely follow those obtained with the Magic Formula even for extreme driving scenarios conducted on roads with low adhesion coefficient.

Passive Feedback Unit for Steer by Wire Systems

Steer by Wire systems remove the need of a mechanical connection between the governing unit (steering wheel) and the actuated element (steered wheel). With respect to traditional steering systems, SbW systems replace complex mechanical and/or hydraulic components with simple mechatronic components that enable programmable steering features, enhancements in cab design, ergonomics and safety, plus advantages in simplified assembly, all at a cost comparable to traditional systems. The objective of this article is to show how the idea of passive SBW system can be translated into an actual device ready for vehicle applications. To fulfill this aim, functional schemes, mechanical and mechatronic structure and some data about obtainable performance are presented.

Comparison of Contact Force Control Strategies on Different Robot Arm Types

Nowadays robots are used in various areas. There are extremely important applications where the robot arm tip comes in contact with the environment or an object. During controlling an object, static or in motion, the object or the robot arm should not be damaged. The interaction forces are important in such conditions. Whether the task succeeds or fails depends on how accurate the interaction forces are controlled. The interaction forces are changed depending on the motion of the robot arm. Therefore, to control interaction forces a force control algorithm must be developed. In this research a force control algorithm will first be developed for the quasi-static contact tasks, then it will be extended to the dynamic cases. The goal of this study is to compare force control strategies to achieve the desired interaction forces between the robot arm tip (end-effector) and the environment during contact tasks. Taguchi L9 method is used for comparison of selected force control algorithms which are modeled in SIMULINK MATLAB program.

Evaluation of the Effect of Gas Leakage on Operation of an Optical Engine

An experimental and numerical study is carried out to evaluate the significance of gas leakage for a non-lube optically accessible internal combustion engine and to obtain estimation for the gas flow out of the combustion chamber at each engine cycle and its effect on the in-cylinder component states during optical engine’s operation. Attention is paid to blow-by and circumferential flow through the gaps between the piston rings and the liner. Optical engines are typically operated without lubrication to avoid window fouling and generation of fluorescence by oil particles that interfere with laser diagnostic signals, in view of this circumstance significant blow-by is expected in optical engines due to lack of “wet-seal” on the cylinder walls which permits circumferential flow of gases through the piston ring pack region resulting in increased blow-by. Semi analytical model estimating the mass loss rate is incorporated into zero dimensional thermodynamic IC engine model which simulates in-cylinder processes. Predicted results are compared for leaking and non-leaking engine simulations.