A linearly conforming radial point interpolation method (LC-RPIM) is presented for stress analysis of two-dimensional solids. In the LC-RPIM method, each field node is enclosed by a Voronoi polygon, and the displacement field function is approximated using RPIM shape functions of Kronecker delta function property created by simple interpolation using local nodes and radial basis functions augmented with linear polynomials to guarantee linear consistency. The system equations are then derived using the Galerkin weak form and nodal integration techniques, and the essential boundary conditions are imposed directly as in the finite element method. The LC-RPIM method is verified via various numerical examples and an extensive comparison study is conducted with the conventional RPIM, analytical approach and FEM. It is found that the presented LC-RPIM is more stable, more accurate in stress and more efficient than the conventional RPIM.

To simulate the contact nonlinearity in 2D solid problems, a contact analysis approach is formulated using incremental form of the subdomain parametric variational principle (SPVP). The formulation is based on a linearly conforming radial point interpolation method (LC-RPIM) using nodal integration technique. Contact interface equations are also presented using a modified Coulomb frictional contact model and discretized by contact point-pairs. In the present approach, the global discretized system equations are transformed into a standard linear complementarity problem (LCP) that can be solved readily using the Lemke method. The present approach can simulate various contact behaviors including bonding/debonding, contacting/departing, and sticking/slipping. An intensive numerical study is performed to validate the proposed method via comparison with the ABAQUS ® and to investigate the effects of the various parameters used in computations. These parameters include normal and tangential adhesions, frictional coefficient, nodal density, the dimension of local nodal support domain, nodal irregularity, shape parameters used in the radial basis function and the external load. The numerical results have demonstrated that the present approach is accurate and stable for contact analysis of 2D solids.

Abstract-This paper proposes a simple method for reducing it was established in [7] [8] that the error was caused by the the rotor position estimation error caused by cross-coupling effect of cross-coupling magnetic saturation between the d-and magnetic saturation between the d-and q-axes when signal q-axes, (i.e., Ldqh#O), and was influenced by the machine injection based sensorless control is applied to a brushless AC (BLAC) motor. The error in the estimated rotor position, which design, but, as yet, no measures, from the control aspect, have results when conventional signal injection sensorless control is been proposed to reduce the error. Nevertheless, it is well employed, is analyzed. Based on an improved model of a BLAC known that a mutual inductance exists between the d-and qmotor which accounts for the influence of dq-axis cross-coupling axes of a BLAC motor (Ldqh) as a result of cross-coupling due to on the high-frequency components of the incremental winding magnetic saturation, as shown in [9], both experimentally and inductances, as deduced by either finite element analysis or from by finite element analysis. However, for simplicity, the

An improved brushless AC motor model is proposed for use in signal-injection-based sensorless control schemes by accounting for cross-coupling magnetic saturation between the -and -axes. The incremental self-and mutual-inductance characteristics are obtained by both finite-element analysis and measurements, and have been successfully used to significantly reduce the error in the rotor position estimation of sensorless control.

Abstract-The paper presents an improved signal injectionbased sensorless control method for permanent magnet brushless AC (BLAC) motors, accounting for the influence of cross-coupling magnetic saturation between the d-and qaxes. The d-and q-axis incremental self-inductances, the incremental mutual-inductance between the d-axis and qaxis, and the cross-coupling factor are determined by finite element analysis. A method is also proposed for measuring the cross-coupling factor which can be used directly in the sensorless control scheme. Both measurements and predictions show that a significant improvement in the accuracy of the rotor position estimation can be achieved under both dynamic and steady-state operation, compared with that which is obtained with the conventional signal injection method.

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