Improved actuator point-to-point positioning performance, as measured by settling time, has been demonstrated in the context of manufacturing automation applications such as circuit board assembly and other product-transfer operations. The control objective is to move a single mass in a single axis from a starting position to a target position following the fastest possible motion trajectory while meeting final-position accuracy requirements. The actuator's achievable force that is available for acceleration is the fundamental variable that determines optimal settling time. The actuator technology employed is the linear variable reluctance motor. Mathematical motor models and simulation programs have been developed to perform several tasks necessary for demonstrating improved actuator performance: (i) optimal commutation under force ripple constraints has been computed to determine ripple-specified force limits and to provide excitation waveforms necessary for force production, (ii) motion profiles for several positioning task scenarios have been generated based on computed ripple-specified force limits, (iii) state space integral position control simulations have been performed to evaluate the degree of success of the proposed relaxation of force ripple constraints in improving settling time and (iv) the computed settling times for positioning tasks have been examined in relation to the copper losses associated with them in order to assess the trade-off. It has been shown that higher force capability is achieved when force-ripple constraints, which have been customarily emphasized in positioning applications, are relaxed. The higher capability is exploited by adopting faster motion trajectories, which are then imposed under feedback control to achieve faster settling time. Improved force capability with relaxed ripple constraints is demonstrated by generating average force versus speed capability curves under ripple constraints ranging from minimal ripple to unconstrained ripple. Improved positioning performance, with relaxed ripple constraints and without violating the final-position accuracy specification, is demonstrated by computing and comparing settling time for multiple positioning tasks with trajectories based on both extremes of force capability, lowest (no-ripple) and highest (unconstrained-ripple) force limits. The results have been demonstrated for two LVR motor configurations: one motor configuration represents typical (switched) linear and rotary variable reluctance motors while the other exhibits features of both switched and synchronous varieties of variable reluctance motors.

O motor linear à relutância variável (MLRV) é uma máquina elétrica alimentada em corrente contínua, com fases excitadas numa sequência determinada. Caracterizado por operar numa ampla faixa de variação de velocidade, é utilizado em aplicações lineares que convertem energia elétrica em força e movimento de translação. A necessidade de dispositivos comutadores de corrente e um sistema de controle requer boa estimativa do perfil de indutância do motor. No entanto, uma vez que o maior entreferro dificulta o cálculo analítico, este perfil deve ser obtido através de métodos numéricos. Neste contexto, este trabalho apresenta um motor linear do tipo fluxo longitudinal de 4 fases, destinado a mover um sistema de translação deslizante de abertura e fechamento. A robustez, a simplicidade de construção e a potência reduzida foram decisivos na escolha do tipo de máquina. A análise via elementos finitos (AEF) é aplicada a fim de determinar o desempenho, qualificado pela auto-indutância das bobinas de fase e pela capacidade de produção da força de propulsão. A AEF também é utilizada na avaliação do fator de ondulação da força (force ripple), altamente presente neste tipo de motor, além da produção de vibração e ruído acústico, decorrentes do mesmo. / The linear variable reluctance motor (LVRM) is an electric machine fed by direct current with excited phases in a given sequence. Characterized by operating in a wide range of speed variation, it is used in linear applications that converts electric energy into force and translation movement. The need for current switching devices and a control system requires a good estimate of the motor’s inductance profile. However, since the larger air gap makes analytical calculation difficult, this profile must be obtained by numerical methods. In this context, this work presents a linear motor of the 4 phase transverse flow type designed to move a sliding translation system of opening and closing. Robustness, simplicity of construction and reduced power are decisive in the choice of machine type. The finite element analysis (FEA) is applied in order to determine the performance, qualified by the self-inductance of phase coils and the propulsion force production capacity. The FEA is also used in the evaluation of the force ripple factor, highly present in this type of motor, besides the production of vibration and acoustic noise arising from ripple factor. / Dissertação (Mestrado)