Linear and angular displacement measuring encoders are the most important measuring tools in the industry. Linear encoders are widely used in various positioning applications, such as numerical controlled (NC) machine tools and factory automation, since they are essential for precision positioning systems. In this study, a capacitive-type linear encoder with un-tethered SLIDER is designed. The main components are made of printed circuit films. Hence, the encoder can be set up in thin inter spaces or on curved surfaces. The encoder consists of a long receiver film and a short transmitter film, respectively containing four-phase and two-phase electrodes. The transmitter is used as a SLIDER and the receiver as a stator. In order to designs an unconstrained SLIDER; the encoder employs a unique approach. Electrical power is supplied to the transmitter film by electrostatic induction which removes electric wires from the SLIDER. In this study the encoder was built using a new signal processing circuit and its performance was evaluated. The new signal processing circuit is more compact and facilitates using this encoder for trade purposes. The result of experimental evaluation shows that the encoder has ±20 micrometers error.

In most literature on lubrication theory, the assumption of Re << 1 is considered to solve the Navier-Stokes equations in which inertial forces are neglected in comparison with the viscous ones. In problems of bearing with high speed motion, neglecting the inertial forces can not be utilized. In this study, the Navier-Stokes equations for a SLIDER bearing are solved, considering both the inertial and the viscous forces. Then, the effective forces were computed and analyzed. Finally, the results were compared with the available approximate ones, which showed close agreements.

In this paper, an improved sample of capacitive-type linear encoder with untethered SLIDER is presented that has higher resolution and lower error. This encoder has a simple structure consisting of two main parts, stator and SLIDER. Both parts are made of hard PCB. The stator has a sequence of four-phase receiver electrodes and the SLIDER contains two-phase transmitter electrodes. The electrical energy is supplied to transmitter electrodes by the electrostatic induction. Therefore, there is no need to connect any wire to the SLIDER. These features make the encoder to use in limited spaces. By improving resolution, smooth and precise movement of motors is facilitated in the closed loop systems. Thus, the improved encoder is equipped with two ground electrodes between the receiver electrodes and induction electrodes on the stator board to reduce electrostatic interface between these electrodes. As, output error goes down. In addition, the step of electrodes are reduced to increase resolution. Making an experimental sample of improved encoder and testing it, showed 15μ m error in 1μ m resolution. This indicates, the error and resolution are improved than the previous one.

In the current study, behavior of crank-SLIDER mechanism with single and multiple clearance joints are analyzed. Using Lankarani-Nikravesh theory for estimating discontinuous contact forces in clearance joints, relevant systems have been mathematically modeled. Through numerical simulations, perturbations in response of mechanisms with clearance joints have been analyzed. Effects of increasing number of clearance joints have been addressed. From comparisons between responses of crank-SLIDER mechanism with a single clearance joint and multiple clearance joints, it is concluded that perturbations intensify as the number of clearance joints in mechanism increases. Nonlinear dynamics of system are analyzed, using Poincare maps and bifurcation diagrams. Effects of joint friction on the response of the mechanism are investigated. Subsequently, a control scheme for providing continuous contact in clearance joints and maintaining a more stable mechanism is pro-posed. Obtained results demonstrate the effectiveness of proposed control method on reducing effect's of clearance and maintaining continuous contact in clearance joint.

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This paper aims to survey a certain type of the SLIDER-crank mechanisms and to compare its performance with the conventional kind for a four-stroke SI engine. This comparison includes the modeling of thermodynamic processes, vibration and internal forces. Moreover, this study explore the advantages and disadvantages of those mechanisms. The parameters used in the study are friction of piston skirt, type of lubrication, the number of rings, amount and duration of the fuel burning, spark advance, mass of the parts, crank angular velocity, thermodynamic properties of inlet air and temperature of the cylinder body.