Vibration Analyses of a Gantry Structure by Mobile Phone Digital Image Correlation and Interferometric Radar

The study presents results from applying the Real Aperture Radar interferometry technique and Digital Image Correlation through a mobile phone camera to identify static and dynamic deformations of a gantry during surveying operations on the Michelangelo’s David at the Galleria dell’Accademia di Firenze Museum in Florence. The statue has considerable size and reaches an elevation of more than seven meters on its pedestal. An ad-hoc gantry was designed and deployed, given the cramped operating area around the statue. The scanner had a stability control system that forbid surveying in instrument movements. However, considering the unicity of the survey and its rare occurrence, the previous survey had been carried out in the year 2000; verifying stability and recording deformations is a crucial task, and necessary for validation. As the gantry does not have an on-board stability sensor, and considering the hi-survey accuracy requested, a redundant, contactless, remote monitoring system of the gantry and the statue stability was chosen to guarantee the maximum freedom of movement around the David to avoid any interference during scanning operations. Thanks to the TInRAR technique, the gantry and the statue were monitored with an accuracy of 0.01 mm. At the same time, a Digital Image Correlation analysis was performed on the gantry, which can be considered a Multi-Degree-Of-Freedom (MDOF) system, to accurately calculate the vibration frequency and amplitude. A comparison between TInRAR and DIC results reported substantial accordance in detecting gantry’s oscillating frequencies; a predominant oscillation frequency of 1.33 Hz was identified on the gantry structure by TinSAR and DIC analysis.

Optimal Cooperative Brake Distribution Strategy for IWM Vehicle Accounting for Electric and Friction Braking Torques

Electric vehicles are spreading in automotive industry pushed by the need of reducing greenhouse gas. However, the use of multiple electric motors, i.e., one per wheel, allows to redefine the vehicle powertrain layout with great benefits on vehicle dynamics. Electric motors braking torque is in general not enough to produce high decelerations. Hydraulic friction brakes are still necessary for safety reasons and to avoid oversized motors. This paper presents a control strategy for distributed electric motors (EM), one per wheel, to maximize the regenerative braking. The controller handles cooperative braking among EMs and hydraulic brakes, which are still necessary to guarantee top braking performance of the car. The proposed algorithm considers the driver requested braking torque as well as the required yaw moment by stability control system. Motor efficiency map and wheel normal load are considered to optimally distribute the torques. With respect to conventional distribution strategies, the presented algorithm improves performance, maximizing the regenerative braking power.

Design and implementation of a stability control system for TCP/AQM network

<p><span>In this work, we used a new approach as active queue management (AQM) to avoid data congestion in TCP/IP networks. The new approach is PSO-PI controller which use the proportional-integral controller as a control unit and particle swarm optimization (PSO) algorithm as an optimization technique to improve the performance of the PI controller and therefore improving the performance of TCP/IP networks as a required goal. The optimization control (PSO-PI) is characterized by access to design and choosing the optimal parameters of </span>(K_1 and K_p) <span>to reach optimal solutions in a short way (fewer iterations). The implementation of the PSO algorithm is achieving by using the mathematical system model and M-file and SIMULINK in Mathlab program. Simulation results show good congestion management performance with PSO-PI controller better than the PI controller as AQM in TCP networks, and the proposed method was very fast and required few iterations.</span></p>

A remote test method for power grid security and stability control system and its engineering application

Security and stability control (SSC) system or special protection system (SPS) is an important means to ensure the safe operation of power grid. In view of the insufficiency that the current open-loop testing method cannot fully test the SSC system on-site, a remote real-time closed-loop test method is proposed. The solutions of key techniques such as information interaction, remote communication and signal conversion in remote test system are studied. Then the platform architecture and standard interface of the remote test system are designed. A remote test platform for SSC system is developed, and there application modes of the platform is deeply analysed. Finally, taking SSC system of Yunnan AC power outgoing grid as pilot application, experiment of two substations on-site is carried out. The results in practical project further prove the effectiveness of the method presented in this paper.

Development and Validation of Electronic Stability Control System Algorithm Based on Tire Force Observation

In view of the higher and higher assembly rate of the electronic stability control system (ESC in short), the control accuracy still needs to be improved. In order to make up for the insufficient accuracy of the tire model in the nonlinear area of the tire, in this paper, an algorithm for the electronic stability control system based on the control of tire force feedforward used in conjunction with tire force sensors is proposed. The algorithm takes into consideration the lateral stability of the tire under extreme conditions affected by the braking force. We use linear optimal control to determine the optimal yaw moment, and obtain the brake wheel cylinder pressure through an algorithm combining feedforward compensation based on measured tire force and feedback correction. The controller structure is divided into two layers, the upper layer is controlled by a linear quadratic regulator (LQR in short) and the lower layer is controlled by PID (Proportional-integral-derivative) and feedforward. After that, verification of the controller’s algorithms using software cosimulation and hardware-in-the-loop (HIL in short) testing in the double lane change (DLC in short) and sine with dwell (SWD in short) conditions. From the test results it can be concluded that the controller based on tire force observation has partially control advantages.