A Capstone Project on Robust Dynamic Positioning and Data Acquisition Systems

The United States Coast Guard is responsible for enforcing Dynamic Positioning System (DPS) standards in the maritime industry. It is important for the members of the U. S. Coast Guard to understand how these systems work. Students have gained a much greater understanding of how DPS platforms work and what might be required to maintain them by building one from scratch. Aside from this, the project has served as a great opportunity to work on a one year term project that may resemble engineering or acquisitions projects that might be encountered in the students’ future careers. The overall goal of the Robust Dynamic Positioning and Data Acquisition System project was to prototype a dynamic positioning system similar to the ones on buoy tenders in the fleet. The primary goal was to maintain a desired heading and position within a certain range. The secondary goals included robust capabilities (the ability to continue functioning despite motor failures) and data acquisition (to analyze system performance post-testing). Students built a vessel from scratch out of a salvage drum and an inner tube for buoyancy. The internal construction consists of three tiers containing batteries at the lowest level, an onboard computer at the second level, and control hardware at the top level (micro controllers, H-bridges, and fuse boxes). Students successfully used a light detection and ranging (LIDAR) device to determine the relative position to two stationary poles. They were able to communicate with the onboard computer via either a wired connection or a remote desktop connection through an ad-hoc wireless network. All programming for this project was done in MATLAB®. Students have completed all project milestones through the application of past courses they have taken in computer control systems, network communication, and digital signal processing at the U.S. Coast Guard Academy. The first challenge of this project was to focus on constructing the vessel and installing the control hardware. One of the obstacles for the students was establishing communication between the various pieces of software, hardware, and the power distribution system. The LIDAR sensor determined the vessel’s relative position and heading to two stationary poles. Using the position and heading resolution algorithms, students conducted a set of system identification tests in an indoor tank to determine how the system reacts to various thrusts from the motors. This allowed students to collect “Open-Loop” system data. Using the data acquisition system, students were able to identify the system and calculate coefficients for the controller and implement a “Closed- Loop” control system. Students successfully implemented a proportional integral derivative (PID) controller that satisfies all design requirements including robust functionality. Currently, all milestones for the project have been accomplished and plans for continuation of the project are underway

Multithreaded Sensor Analysis for a Redundant Dynamic Positioning 2 Project

The goal of the electrical engineering capstone project, Dynamic Positioning 2 (DP2), is to prototype a controlled dynamic positioning system that has a single-failure safe capability. The primary objective is for the platform to maintain a desired heading and position within ten degrees and three hundred millimeters, respectively, using data obtained from three light detection and ranging (LIDAR) sensors. The secondary objective is for the control system to compensate for the failure of a single sensor or motor. The platform for the DP2 project is a salvage drum that encases the electronic equipment and an inner tube for buoyancy. The internal construction consists of three tiers containing batteries at the lowest level, an onboard computer at the second level, and control hardware at the top level. The platform is tested in an indoor tank with an area of sixteen meters squared. The vessel’s position is calculated from the LIDAR data (bearing and range) to eight stationary poles that mark the outside of the tank using an overdetermined least squares matrix solution. The heading is calculated using the bearings and ranges to specific pairs of poles. An ad-hoc wireless network is used to communicate with the onboard computer while it is operating. All programming was completed in the NET Framework and MATLAB®. Students complete the project milestones through the application of material from past courses in computer control systems, software engineering, and electronic navigation at the U.S. Coast Guard Academy. The DP2 project is sponsored by the Marine Safety Center (MSC)

A Unified Approach for Robust Stability Design of PID Controllers

Abstract-In this paper a graphical technique is introduced for finding all continuous-time or discrete-time proportional integral derivative (PID) controllers that satisfy a robust stability constraint for an arbitrary order transfer function with time delay. These problems can be solved by finding all achievable PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. The key advantage of this procedure is that this method depends only on the frequency response of the system. The ability to include the time delay in the nominal model of the system will often allow for designs with reduced conservativeness in plant uncertainty and an increase in size of the set of all PID controllers that robustly stabilize the system. The delta operator is used to describe the controllers in a discrete-time model, because it not only possesses numerical properties superior to the discrete-time shift operator, but also converges to the continuous-time controller as the sampling period approaches zero. A unified approach allows us to use the same procedure for discrete-time and continuous-time robust stability design of PID controllers

The effect of Coriander cream on healing of superficial second degree burn wound

Background: Coriander with the binominal name of Corianda Sativum, is one of the oldest medicinal plants ever known to man. Anti-inflammatory, anti-microbial, and anti-fungal effects of its oil has been mentioned in numerous studies. This study examines the impact of coriander cream on wound healing of the second-degree singe burn. Methods: In this experimental study which was performed in the animal lab of the Hazrat Fatemeh Hospital in Tehran, 48 adult male rats with an approximate weight of 250-300 grams, with deep burns of 2 cm 4×2 dimensions were prepared and divided into 4 groups of 12. We used silver sulfadiazine cream, alpha ointment, coriander cream and vaseline gauze (control group) dressings in burn wound of the groups 1 to 4 respectively. At the end of the study (30 days), rats were euthanized with a high dose of thiopental and the wounds were evaluated on days 10 and 17 with a punch biopsy. Samples were fixed with 10% formalin on histopathology slide using haematoxylin and eosin (H&E) staining (to assess and determine the presence of inflammatory cells). The amount of fibrin and collagen at the site were evaluated using a software program ImageJ, version 1.45 (National Institutes of Health, Bethesda, Maryland, USA). Results: The mean of wound surface area in the first photography was no significant (P= 0. 135). The rate of wound healing in alpha ointment and coriander cream had better outcomes than either of the other two groups (P= 0.000). The healing of the wound in silver sulfadiazine group was significantly less than other groups. Pathology results showed a statistically significant difference between the four groups (coriander, alpha, SSD and control), based on the Kruskal-Wallis test. These relate to (1) polymorphonuclear in the first (P= 0.032) and the second series (P= 0.003), (2) Angiogenesis in the second series (P= 0.004). (3) Fibrosis in the first series (P= 0.024) and the second series (P= 0.000). Conclusion: The results of this study showed that wound healing improvement in coriander cream group was better than the control group and silver sulfadiazine group; and similar to alpha ointment group