Transactions of the Canadian Society for Mechanical Engineering
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Volume 36 (2012), Issue 1
Stress optimization of coupling pins for large diameter reaming tool of coal-bed methane well
Shu-Lin Liu, Rui Liu, Xue-Hong Zhang, JI-Cheng Liu, Hai-Tao Jiang, Jun-Ran Zhou
The paper focuses on the dynamics optimization of the pin joints which determine the operating performance and life of a novel Large-diameter Coal-bed Methane Reaming Tool (LCMRT). For this purpose, the constraint force equations of the pin joints for LCMRT are first established using Newton-Euler dynamics theory. Moreover, the virtual prototype model of LCMRT is created for dynamics simulations. Based on the dynamics simulations, the constraint forces of the pin joints are shown. Size optimization results for LCMRT are exhibited and described in detail through parametric model. Finally, the results of dynamics simulations based on the LCMRT optimized are demonstrated to validate optimization effect.
Slip-line modeling of machining and determine the influence of rake angle on the cutting force
In this study, the effects of the rake angle on main cutting force (Fc), and thrust forces (Ft) was investigated. A new slip line model approach for modelling the orthogonal cutting process was proposed. This model was applied at negative rake angles from 0° to 260° and consists of three regions. The main forces were measured with a computer aided quick stop device. Variance Analysis (ANOVA) was utilized to analyze the effects of the cutting parameters on cutting and thrust forces accordingly. Multi-variable regression analysis was also employed to determine the correlations between the factors and the cutting forces. The cutting forces could be calculated by equation parameters which are the rake angle and the uncut chip thickness.
Investigation of effect on lateral displacement and forces of cutting mode in sawability of metal profile using cutting disc
In this study, the cutting performance of cutting discs used to cut metal materials depending on the cutting modes is determined with an experimental study. Tests are performed using a computer-controlled cutting machine. For the tests, peripheral speeds of 40, 60 and 80 m/sec and feed speeds of 0.3, 0.4, 0.5, 0.6, and 0.7 m/min. are preferred as cutting parameters. Up cutting and down cutting are taken into consideration as cutting modes. A three-point dynamometer is used to determine the forces applied on the disc during cutting. A KEYENCE laser displacement measuring device is used to measure lateral displacements of the cutting disc. According to the test results, feed speed is observed as a significant parameter in determining the cutting forces and lateral displacements. Up and down cutting modes used in the study has a significant effect on determining the forces applied on the cutting disc and lateral displacements of the disc. In particular, lateral displacements obtained in down cutting mode are observed to be greater than the displacements obtained in up cutting mode.
Methodology of the assessment of the abrasive tool's active surface using laser scatterometry
Wojciech Kaplonek, Czeslaw Lukianowicz, Krzysztof Nadolny
Diagnostics of abrasive tools requires the use of modern measurement techniques which allows for fast assessment of a surface in order to determine, for example, the degree of its wear or to detect various type of defects. A wide group of optical measurement methods used for this type of assessment are based on the phenomenon of light scattering. One such method based on imaging and analysis of light scattering from a surface is laser scatterometry. In this paper, by utilizing laser scatterometry supported by image analysis techniques, a proposal for a methodology of assessment of the degree to which smearing of the grinding wheel active surface (GWAS) occurs during the plunge grinding process, was presented and discussed. Select results of experimental investigations carried out on bearing steel 100Cr6 were also presented. The obtained results confirmed the efficacy of the above-mentioned techniques that could be an interesting alternative to other methods already used in such measurements.
The dof degeneration characteristics of closed loop overconstrained mechanisms
Sheng Guo, Haibo Qu, Yuefa Fang, Congzhe Wang
A new terminology, "degenerative degrees of freedom," to describe mechanisms possessing different degrees of freedom (DOF) while containing the same number of linkages and joints is introduced. A systematic approach is developed for studying this particular type of closed loop mechanism and its degeneration characteristics of DOFs. First, the single closed loop over-constrained mechanism is analyzed and a relationship between the number of over-constraints and the number of joints and DOFs is established. Then, all possible types of independent over-constraints and their combinations are summarized. Further the non-instantaneous condition of the mechanism is analyzed by using an analytical method. The paper delineates three rules that provide the guidelines for the layout of joints, linkages and their assembly. Finally, the degenerative characteristics of all such mechanisms are systematically tabulated along with sketches of some typical ones. To corroborate the literature an example involving two 6R closed loop mechanisms with 1 and 3 DOFs respectively is presented and analyzed, thus validating their degenerative characteristics.
Effect of servo systems on the contouring errors in industrial robots
Mohamed Slamani, Albert Nubiola, Ilian A. Bonev
Two important aspects of the performance of a servo system, tracking errors and contour errors, significantly affect the accuracy of industrial robots under high-speed motion. Careful tuning of the control parameters in a servo system is essential, if the risk of severe structural vibration and a large contouring error is to be avoided. In this paper, we present an overview of a method to diagnose contouring errors caused by the servo control system of an ABB IRB 1600 industrial robot by measuring the robotís motion accuracy in a Cartesian circular shape using a double ballbar (DBB) measurement instrument. Tests were carried out at different TCP (tool centre-point) speed and trajectory radii to investigate the main sources of errors that affect circular contouring accuracy. Results show that radius size errors and out-of-roundness are significant. A simple experimental model based on statistical tests was also developed to represent and predict the radius size error. The model was evaluated by comparing its prediction capability in several experiments. An excellent error prediction capability was observed.
Real-time mark-on-windshield warning system for intelligent vehicles
Chyi-Yeu Lin, Jinn-Feng Jiang, Yi-Jie Chen, Hung-Tuan Wei, Hou-An Chen
The present study proposes a mark-on-windshield warning system for vehicles that allows the driver to see potentially hazardous objects in front of the vehicle without taking his eyes off the road. An identified target is used to construct the line-of-sight equation based on the coordinate system of the moving vehicle. The explicit equation of the intersection point of the line of sight and the windshield surface is derived using an algebraic method. A warning mark is projected at the intersection point on the windshield by a two-degree-of-freedom laser projector unit, allowing the driver to easily identify the obstacle. An augmented reality verification platform is constructed to demonstrate the feasibility of the proposed system.
Full journal title: Transactions of the Canadian Society for Mechanical Engineering
Abreviated journal title: Trans. Can. Soc. Mech. Eng.
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