A Multiobjective Parametric Optimization for Passenger-Car Steering Actuator

A robust design for the size optimization of a motor-driven steer applied in a compact car, using the design of simulation trial, is described and illustrated in this paper. The objective of the optimal design using the combined design of simulation trial and finite-element analysis (FEA) approach is to ensure that the motor-driven steer's performance for compact cars is insensitive to noise, with moderate computational effort. The optimal design process takes into consideration noises that arise in the unexpected load condition, such as tolerances for parameter variation of the electric motor and reduction gear in the actuator. The optimization is realized by a simulation and analysis tool that integrates the Target-wise Parameter Optimization and the FEA. The proposed procedure can not only reduce the size of an actuator but also raise the system efficiency of the motor-driven steering (MDS). In this paper, we have used an orthogonal array L18(2(1) x 3(7)) to implement simulation trials and made a response table and graph of control factors. Eventually, the optimal values of the control factors, the diameter of the stator core, the width of the wire, the turn number of the wire, the gear ratio of the worm and worm-wheel gear, the surface flux density of the magnet, the armature core's stack factor, and the module ratio of the worm and worm-wheel gear were decided, and then, the signal-to-noise ratio (SNR) was increased to 20.58%. The simulation results demonstrated that the proposed method applied to the optimal design of the MDS' actuator was feasible and efficient. In this paper, the design optimization process is described, and the results are presented.