In existing multi-population cultural algorithms, information is exchanged among sub-populations by individuals. However, migrated individuals cannot reflect enough evolutionary information, which limits the evolution performance. In order to enhance the migration efficiency, a novel multi-population cultural algorithm adopting knowledge migration is proposed. Implicit knowledge extracted from the evolution process of each sub-population directly reflects the information about dominant search space. By migrating knowledge among sub-populations at the constant intervals, the algorithm realizes more effective interaction with less communication cost. Taken benchmark functions with high-dimension as the examples, simulation results indicate that the algorithm can effectively improve the speed of convergence and overcome premature convergence.

For a bilaterally symmetric type hybrid mechanism used for automobile electro-coating conveying, the controller based on a novel synchronization error is proposed to improve the synchronization performance of the mechanism motion. The Jacobi matrix of the mechanism is calculated according to kinematic analysis, and the dynamic model is established by Lagrange method. Considering the structure and motion characteristics of the mechanism, a novel synchronization error is proposed. By combining cross-coupling control with sliding mode control, a novel synchronization controller based on the novel error is designed. The stability of the proposed algorithm is proved by Lyapunov stability theorem, and the convergence of the tracking error is proved with Barbalat’s Lemma. The simulation and experimental results show that the synchronization controller based on the novel error can not only have the superiority of designing the controllers in the task space but also avoid the problem of estimating the contour error when using contour error as the synchronization error.

For a hybrid mechanism used for automobile electro-coating conveying, a chattering-free sliding mode synchronization controller is proposed to improve the synchronization performance during motion process. The Jacobi matrix of the mechanism is calculated according to kinematic analysis, and the dynamic model is established by Lagrange method. Since the mechanism consists of two sets of hybrid mechanisms bilaterally, a novel synchronization error including the synchronization error between two ends of the end-effector is designed. By combining cross-coupling control with chattering-free sliding mode control, a novel chattering-free sliding mode synchronization controller is proposed. The stability of the proposed algorithm is proved by Lyapunov stability theorem. The simulation and experimental results show that the proposed controller can effectively reduce the chattering of driving forces and further improve the synchronization performance and tracking accuracy of the system.

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