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The dynamic modeling and trajectory tracking control of a mobile robot is handled by a hierarchical constraint approach in this study. When the wheeled mobile robot with complex generalized coordinates has structural constraints and motion constraints, the number of constraints is large and the properties of them are different. Therefore, it is difficult to get the dynamic model and trajectory tracking control force of the wheeled mobile robot at the same time. To solve the aforementioned problem, a creative hierarchical constraint approach based on the Udwadia–Kalaba theory is proposed. In this approach, constraints are classified into two levels, structural constraints are the first level and motion constraints are the second level. In the second level constraint, arbitrary initial conditions may cause the trajectory to diverge. Thus, we propose the asymptotic convergence criterion to deal with it. Then, the analytical dynamic equation and trajectory tracking control force of the wheeled mobile robot can be obtained simultaneously. To verify the effectiveness and accuracy of this methodology, a numerical simulation of a three-wheeled mobile robot is carried out.

The teaching of the traditional mold courses focus on the illustration of theoretical knowledge. Therefore, associating the design, evaluation, and manufacture links as a whole is difficult. Students cannot shape system knowledge, thereby making the study difficult. In addition, traditional teaching cannot meet the current enterprise needs of talents who have mold CAD/CAE/CAM technology. This study presents a teaching method that applies CAD/CAE/CAM technology to mold teaching. First, the positive effects of these technologies on the mold design and manufacturing process are introduced. Thereafter, lamp cover is used as an example to establish a series of computer-aided teaching development processes using existing software for mold design, mold flow analysis, and machining simulation. Lastly, survey results demonstrate that the effects of the proposed teaching method are better than the traditional method. Moreover, students and enterprises are substantially recognized in this teaching method.

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