Optimal placement of inherent zeros in polynomial-based motion profiles for minimizing residual vibration and travel time under system uncertainties.

Various industrial processes require motion profiles that determine machine movement over time for workpiece transfer, with the goal of minimizing transfer time to enhance productivity. However, pursuing the maximum speed can trigger excessive motion-induced vibration, which can reduce the manufacturing efficiency, accuracy and operational lifespan of the system. This study proposes a generalized motion profile optimization method that considers the strategic placement of inherent zeros within the motion profile: each inherent zero contributes to the reduction of residual vibration or optimization of arrival time. By offering freedom to the placement of zeros, four optimization options for polynomial-based motion profiles of each order are proposed, expanding on existing work that offered a single option. All proposed optimization options have closed-form solutions, making them easily applicable to industrial applications. The practical applicability of the suggested methodology is demonstrated through case studies and experiments.

Experimental development of levitation control for a high-accuracy magnetic levitation transport system.

In this paper, we present the experimental levitation control development in a high-accuracy magnetic levitation transport system. With this levitation control implementation, the input and output of sub-systems can be verified through a real-time system. The levitation control loop has a fast response, and the control algorithms are easily implemented. In addition, a notch filter and a low-pass filter are designed to minimize mechanical resonance and sensor noise, respectively. Moreover, a section control algorithm is developed to reduce sudden changes in the levitation forces. From the results, the total current required to levitate the carrier is approximately 3.1 A, and it is decreased to approximately 2.45 A at the desired airgap. The maximum peak-to-peak variation of the airgap measurement at a standstill is approximately 50µm, and at low and high movement speeds, it is approximately 300µm and 700µm, respectively. Moreover, the good levitation control performance in the deadzone, where one pair of the levitation electromagnets is disabled, is also verified.