In this paper, a zero-phase odd-harmonic repetitive control scheme is proposed for pulse-width modulation inverters. The proposed repetitive controller combines an odd-harmonic periodic generator with a noncasual zero-phase compensation filter. It occupies less data memory than a conventional repetitive controller does. Moreover, it offers faster convergence of the tracking error, and yields very low total harmonics distortion (THD) and low tracking error. Analysis and design of the proposed system are presented. Experimental results with the proposed repetitive controller are presented to validate the approach. The phenomena of even-harmonic residues in the proposed control system is discussed and experimentally demonstrated.@en

In this paper, the robustness stability and performance of robust repetitive control scheme is analyzed and synthesized by the structured singular value theory. A linear phase lead is introduced to improve the performance of robust repetitive control system. It compensates the phase lag of feedback control system and widens the cutoff frequency of Q filter. The periodic disturbance rejection performance of system is improved. Experiment results of a PWM converter system are presented to demonstrate the efficiency of the proposed approach.@en

(Semi)- Automatic facade reconstruction from terrestrial LiDAR point clouds is often affected by both quality of point cloud itself and imperfectness of object recognition algorithms. In this paper, we employ regularities, which exist on façades, to mitigate these problems. For example, doors, windows and balconies often have orthogonal and parallel boundaries. Many windows are constructed with the same shape. They may be arranged at the same lines and distance intervals, so do different windows. By identifying regularities among objects with relatively poor quality, these can be applied to calibrate the objects and improve their quality. The paper focuses on the regularities among the windows, which is the majority of objects on the wall. Regularities are classified into three categories: Within an individual window, among similar windows and among different windows. Nine cases are specified as a reference for exploration. A hierarchical clustering method is employed to identify and apply regularities in a feature space, where regularities can be identified from clusters. To find the corresponding features in the nine cases of regularities, two phases are distinguished for similar and different windows. In the first phase, ICP (iterative closest points) is used to identify groups of similar windows. The registered points and a number of transformation matrices are used to identify and apply regularities among similar windows. In the second phase, features are extracted from the boundaries of the different windows. When applying regularities by relocating windows, the connections, called chains, established among the similar windows in the first phase are preserved. To test the performance of the algorithms, two datasets from terrestrial LiDAR point clouds are used. Both show good effects on the reconstructed model, while still matching with original point cloud, preventing over or under-regularization.@en

The significance of phase-lead compensation is revealed for repetitive control systems in terms of tracking accuracy and transient. A real-time noncausal phase-lead FIR filter is proposed to improve the performance of add-on repetitive controlled constant-voltage constant-frequency PWM dc¿ac converters. The experiment results show that nearly perfect tracking, low total harmonics distortion, and satisfactory transient are achieved in the proposed repetitive-controlled PWM converter under both linear load and rectifier load.@en

In this paper, the robustness stability and performance of robust repetitive control scheme is analyzed and synthesized by the structured singular value theory. A linear phase lead is introduced to improve the performance of robust repetitive control system. It compensates the phase lag of feedback control system and widens the cutoff frequency of Q filter. The periodic disturbance rejection performance of system is improved. Experiment results of a PWM converter system are presented to demonstrate the efficiency of the proposed approach.@en