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Being the earliest form of additive manufacturing, stereolithography (SLA) fabricates 3D objects by selectively solidifying the liquid resin through a photopolymerization reaction. The ability to fabricate objects with high accuracy as well as a wide variety of materials brings much attention to stereolithography. Since its invention in the 1980s, SLA underwent four generations of major technological innovation over the past 40 years. These innovations have thus resulted in a diversified range of stereolithography systems with dramatically improved resolution, throughput, and materials selection for creating complex 3D objects and devices. In this paper, we review the four generations of stereolithography processes, which are scanning, projection, continuous and volumetric stereolithography. For each generation, representative stereolithography system configurations are also discussed in detail. In addition, other derivative technologies, such as scanning–projection, multi-material, and magnetically assisted stereolithography processes, are also included in this review.

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In this paper, a proportional integral (PI) controller that optimized with the modified different evolutional (DE) algorithm is proposed for speed control of brushless direct-current (BLDC) motor. The parameters of PI controller are tuned by the modified DE algorithm which based on adaptive mutation factor, multivariable fitness function and the starting rule for the modified algorithm. The performances of proposed controller, the conventional PI controller and the PI controller optimized with standard DE controller (PI-SDE controller) are investigated and compared in simulation. Also, the proposed controller is compared with other optimization controller in this study. The simulation results and the experimental verification show that the proposed controller leads to the smaller overshoot, less setting time and rising time compared to other controllers in this study. The results also show that the proposed controller can accelerate the response speed of BLDC motor, strengthen the robustness and guarantee motor runs smoothly as well as precisely. This work indicates the distinguished performance of proposed controller for the speed control of BLDC motor.

This paper presents an anti-windup self-tuning euzzy proportional-integral-derivative (PID) controller for the speed control of brushless direct-current (BLDC) motor. The proposed controller consists of a self-tuning fuzzy PID controller and an snti-windup controller, which combines the merits of these two controllers. The anti-windup controller is designed as a fuzzy proportion controller and is switched by a logic function based on the output of proposed controller and the speed error. A detailed simulation study in MATLAB/Simulink is performed to investigate the performance of proposed controller, and the simulation experiments are conducted on different conditions. The control system parameters of the proposed controller such as overshoot, settling time and rising time are compared with that of the conventional PID controller. The simulation results show that the proposed controller can accelerate the response speed of BLDC motor, strengthen the ability of anti-windup and make motor runs smoothly, it is proven that anti-windup self-tuning fuzzy PID controller has better performance than conventional PID controller.