Transactions of the Canadian Society for Mechanical Engineering
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Volume 41 (2017), Issue 1
The study to apply fuzzy weighted input estimation for the prediction of target trajectory in a fire control system
Yi-Wei Chen, Yung-Lung Lee, Yen-Bin Chen
The fuzzy weighted input estimation (FWIE) is proposed in this paper to solve the problem of noise disturbance and combined with the three-dimensional motion equation of target trajectory to construct the tracking rule of fire control system. FWIE can estimate effectively the input data of maneuvering target acceleration to obtain the precise target state and solve the problems from the traditional Kalman filter which cannot compute the precise estimation of target state because of the input information in the system. Simulation results show that FWIE can estimate the change of target state rapidly and precisely compared with the extended Kalman filter and the proposed tracking rule can improve the fire control system to figure out the target intercepting points with shorter miss distance.
Optimal design parameters of reconfigurable robots with lockable joints
Gabriel Zeinoun, Ramin Sedaghati, Farhad Aghili
This paper presents a global optimization methodology to find the optimal Denavit–Hartenberg parameters of a serial reconfigurable manipulator minimizing a cost function over a pre-specified workspace volume and given lower and upper bounds on the design parameters. Different cost functions such as the manipulability measure, maximum force capability of the manipulator’s end-effector, and maximum velocity capability of the manipulator within the operating workspace of the manipulator are considered to optimize the kinematic design. Based on a combination of genetic algorithm (GA) and sequential quadratic programming (SQP), a modified global and posture-independent parameter of singularity (MPIPS) is presented. Finally, a weighted objective function is proposed to balance between the conflicting requirements for manipulator’s force and velocity capabilities.
Mechanical characterization of notched hot rolled multi-phase steel
Ke Niu, Abdolhamid Akbarzadeh, Zengtao Chen
This paper presents a series of experimental and numerical studies on Hot Rolled Stretch Flanging steels. This study focuses on four prototyped Hot-Rolled Stretch Flanging steels (HR780SF). Circular- notched sheet steel samples are used to induce different stress triaxiality levels in the rolling direction of sheet materials. Digital image correlation technique measures the local true strain during the deformation process of the notched samples in uniaxial tensile test. The microstructure of the notched samples is examined to evaluate the effect of geometrical features of circular notches on the microstructural evolution during the plastic deformation. Finally, the numerical results obtained via a finite element simulation are validated by the collected experimental data. Our experimental studies reveal the possibility of crack formation along the width of HR780SF steels during the mechanical load. The crack formation, which deteriorates the structural performance of hot rolled steels, can be avoided by the heat treatment of samples prior to the mechanical tests. In addition, it is found that the effect of notch geometry on the stress state is much more considerable at the notch edge than the notch center.
The design of hybrid electromechanical valve actuator: Effects of construction parameters
Jawad Aslam, Xing-Hu Li, Hai Sun
In this paper, a novel modified cylindrical core, axis symmetric, low-inductance, hybrid permanent magnet (PM) / electromagnet (EM) magnetomotive force (MMF) actuator is proposed for variable valve timing camless engine. The new design provides large magnetic force with low energy consumption (startup and holding force), permanent magnet demagnetization isolation and improved transient response. The design and construction parameter sensitivity simulation results confirm the force of approximately 200 N (in the presence of coil current) and 500 N (in the absence of coil current) at equilibrium position and armature seat, respectively. An improvement in transition time due to low coil inductance, flexible control with parallel coils and 41.96% low energy dissipation is observed.
Experimental comparison between proportional and PWM-solenoid valves controlled servopneumatic positioning systems
Ramhuzaini Abd. Rahman, Nariman Sepehri
The performance of the Dynamical Adaptive Backstepping-Sliding Mode Control (DAB-SMC) scheme for positioning of a pneumatic cylinder regulated by two types of PWM-solenoid valves is experimentally investigated. The goal is to study the compromise in controller’s performance as the system moves from using a proportional valve to employing the low-cost PWM-solenoid valves. Sinusoidal and multiple-step inputs are used as the reference position trajectories. Experimental results show that the DAB-SMC scheme works best with the proportional valve. The performance, however, deteriorates by more than twofold, once the system utilizes PWM- solenoid valves of 3/2-way or 2/2-way configurations. From this study, tradeoff between performances of different types of valves applied on a DAB-SMC scheme-controlled servo positioning system is successfully documented. This information helps to configure appropriate servopneumatic system for positioning applications.
Stabilized mixed finite element method for transient darcy flow
Shahab U. Ansari, Masroor Hussain, Sarvat. M. Ahmad, Ahmar Rashid, Suleman Mazhar
Darcy flow is a steady-state model for laminar flow of a fluid through a porous medium. The present work proposes an extended model of laminar Darcy flow by introducing dynamic pressure and velocity to the classical formulation. The solution of the proposed time-space model is attained by discretizing the problem with a stabilized mixed Galerkin method in space and a forward Euler method in time. The resulting matrix equation is well-posed and is solved using the conjugate gradient (CG) method. The error analysis of the numerical solutions confirms convergence to the actual model.
Vibration of road bridges under moving vehicles: A comparative study between single contact point and two contact point models
Tanuja Vaidya, Animesh Chatterjee
The study of dynamic response of bridges under the action of moving vehicles provides a tool for structural designing as well as damage identification. Bridge-vehicle interaction is generally modelled through single contact point for mathematical simplicity, although the interaction actually takes place through front and rear wheels. In the present work, dynamic deflection of the bridge modelled through two contact points is investigated for a range of vehicle velocity and wheel to wheel distance. It is observed that for wheelbase to bridge span ratio greater than a certain limit, two contact point model gives significantly different results particularly at higher velocity range. The results, presented in terms of non-dimensional parameters, can be used as a design monograph for any bridge-vehicle-velocity combination.
On the design of integrated permanent-magnet rotating electric motors with gear mechanisms
Guan-Chen Chen, Hong-Sen Yan
This work presents a novel design procedure for integrated permanent-magnet rotating electric motors with gear mechanisms. A DC commutator motor and a planetary gear mechanism are used as an example. Based on the design requirements and constraints, the detailed design of the rotor and stator are obtained. A 1-D equivalent magnetic circuit method is applied to analyze the integrated device performance and is verified by FEM software. The design methods for gear trains, gear profiles, numbers of gear teeth, and gear strength are also introduced. Finally, a feasible integrated device is presented that reduces the cogging torque and the torque ripple by 92.02 and 50.14%, respectively, while increasing the torque density by 16.66%.
Prediction and investigation of surface roughness while turning SG iron with cubic boron nitride (CBN) and tungsten carbide inserts
K.M. Kumar, P. Hariharan
This work compares the effect of cubic boron nitride (CBN) and multilayer (TiCN+Al2O3+TiN) coated tungsten carbide (WC) tools during the turning of spheroidal graphite (SG) nodular iron. Nodular irons have more ductility which is required in mechanical components that demand high fatigue resistance like crankshafts, cam shafts, bearing caps and clutch housings. The impact of various process parameters like the depth of cut, cutting speed and feed on the surface roughness (Ra) of SG iron is studied and optimized using the response surface model. The chip morphology is also discussed for evaluation of the quality of the turned surface. The experimental outcomes reveal that the WC tool offers a high surface finish at the optimal combination of the cutting speed at 102 meter/minute, feed at 0.051 millimeter/revolution and depth of cut at 0.5 millimeter and that, for the CBN insert, at 245 meter/minute of cutting speed, 0.051 millimeter/revolution of feed and 0.75 millimeter of depth of cut.
A cam-geared mechanism for rigid body guidance
A cam-geared mechanism, consisting of a disk cam with a radially translating roller follower, a disk cam with an oscillating roller follower and an elementary planetary gear train is proposed for rigid body guidance. A design method of cam profile based on inverse kinematic analysis was also proposed. An example is provided to show the feasibility and effectiveness of this proposed method. The advantages of the new design include its simple, compact structure and simple design procedure.
Surface azimuthal anchoring energy between the grating surface and nematic liquid crystal layer studied by using a geometric model
Chin-Lung Lin, Tei-Chen Chen
A simple geometric model is proposed for estimating the azimuthal anchoring energy between the sinusoidal relief grating surface and nematic liquid crystal layer of a liquid crystal display (LCD) device as a function of the grating height and grating pitch. The model parameters are determined experimentally, and the model is then used to predict the surface azimuthal anchoring energy for gratings with various pitches and heights. It is shown that a good agreement exists between the predicted results for the surface azimuthal anchoring energy and the experimental data. Moreover, a good agreement is also observed between the estimated results and those obtained from Berreman’s expression and finite element method (FEM) simulations, respectively. Overall, the experimental and numerical results show that for the nematic liquid crystal considered in the present study (4-n-pentyl-4’-cyanobiphenyl (5CB)), the surface azimuthal anchoring energy increases with an increasing grating height or a reducing grating pitch.
Full journal title: Transactions of the Canadian Society for Mechanical Engineering
Abreviated journal title: Trans. Can. Soc. Mech. Eng.
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