Optimization of automatic control of the speed of rotation of a marine diesel engine

Annotation – The well-established method of tuning the speed governors (SG) of diesel engines during their operation under conditions of step disturbances, which are characteristic of diesel-generators, cannot be used for the main marine engines, the dynamic modes of which are associated, first of all, with heavy seas, because disturbances cannot change stepwise both along the channel for setting the rotational speed and along the load channel. In this regard, the practical need for the development of a method for tuning the SG of the main engines, which takes into account the peculiarities of their operation in heavy seas, has been determined. The study simulates the automatic speed control system (ASC) of the main marine engine HYUNDAI – MAN B&W 6G70ME-C9.2 of the large crude carrier "GOLDWAY" with the AutoChief 600 electronic SG. The minimum of instability of the controlled parameter was used as an optimality criterion, i.e. the amplitude of the oscillations of the rotational speed of the diesel engine shaft, with the most probable values of the amplitude and period of oscillations (rolling) of the disturbing effect. The study has established that changing the tuning parameters of the governor may lead to local extrema of the optimality criterion when using an electronic governor in the ACS in the factor space of disturbances on a diesel engine, which are typical for heavy seas. It means that the task, requiring finding local extrema using specialized methods, can be set when using an electronic governor in the ACS. However, a significant decrease in the instability of the rotational speed was achieved by carrying out a simple enumeration of the tuning parameters of the SG. It was also found that with a "heavy" propeller, the rotational speed stability can be increased by decreasing the proportional gain, as well as increasing the integrator time.

Realization of the Ultrasonic Motor Speed Control System Based on H-Bridge

In view of the requirement that the speed of rotor speed of ultrasonic motor can be stabilized quickly, combined with the mathematical model of two-phase traveling wave ultrasonic motor, we designed the rotor speed stability control strategy of the two-phase traveling wave ultrasonic motor based on voltage and current double feedback. We simulated, analyzed, and verified the designed strategy using Matlab/Simulink simulation tool. The rationality of the simulation results proves the correctness of the designed control strategy, which lays a theoretical foundation for the production design of two-phase traveling wave ultrasonic motor.

A bio-inspired robotic climbing robot to understand kinematic and morphological determinants for an optimal climbing gait

Robotic systems for complex tasks, such as search and rescue or exploration, are limited for wheeled designs, thus the study of legged locomotion for robotic applications has become increasingly important. To successfully navigate in regions with rough terrain, a robot must not only be able to negotiate obstacles, but also climb steep inclines. Following the principles of biomimetics, we developed a modular bio-inspired climbing robot, named X4, which mimics the lizard’s bauplan including an actuated spine, shoulders, and feet which interlock with the surface via claws. We included the ability to modify gait and hardware parameters and simultaneously collect data with the robot’s sensors on climbed distance, slip occurrence and efficiency. We first explored the speed-stability trade-off and its interaction with limb swing phase dynamics, finding a sigmoidal pattern of limb movement resulted in the greatest distance travelled. By modifying foot orientation, we found two optima for both speed and stability, suggesting multiple stable configurations. We varied spine and limb range of motion, again showing two possible optimum configurations, and finally varied the centre of pro- and retraction on climbing performance, showing an advantage for protracted limbs during the stride. We then stacked optimal regions of performance and show that combining optimal dynamic patterns with either foot angles or ROM configurations have the greatest performance, but further optima stacking resulted in a decrease in performance, suggesting complex interactions between kinematic parameters. The search of optimal parameter configurations might not only be beneficial to improve robotic in-field operations but may also further the study of the locomotive evolution of climbing of animals, like lizards or insects.

Robotic wheel structures and their industrial applications based on motion simulations

The following work was done to analyze mobile structures with different arrangements of wheels. Software package Solidworks was utilized in modeling and analysis of the structures. Eight mobile structures were built by rearranging the placement of both driven and free wheels. Each structure has its own unique placement of wheels, hence giving the opportunity to understand the influence of the wheels’ placement on the functionality of the whole structure in terms of speed, stability, and other parameters. Therefore, eight mobile structures were analyzed, and the results were gathered. Adding more driven wheels or free wheels does not improve the performance of the mobile structures. The outcomes of the results illustrated that structure 6 tends to be more positive in terms of energy consumption, torque, and stability. Hence, adding more driven wheels does not improve the performance of the mobile structures.

Safety Evaluation of Fog Warning Systems in a Connected Vehicle Environment Based on Sample Entropy

Changes in driving behavior caused by reduced visibility in fog can lead to crashes. To improve driving safety in fog weather, a fog warning system based on connected vehicle (CV) technology is proposed. From the perspective of human factors, this study evaluates the driving safety based on drivers’ speed change under different fog levels (i.e., no fog, light fog, and heavy fog) and different technical levels (i.e., normal, with a dynamic message sign (DMS), and with a human-machine interface (HMI)). The driving behavior data were collected by a driving simulation experiment. The experimental road was divided into three zones: clear zone, transition zone, and fog zone. To quantify the change of vehicle speed comprehensively, the speed and acceleration were selected. Meanwhile, the vehicle speed safety entropy and acceleration safety entropy were proposed based on sample entropy theory. Furthermore, the changes of each index in different zones were analyzed. The results show that the use of fog warning system can improve speed stability and driving safety in fog zones and can make the driver decelerate in advance with a smaller deceleration before entering the fog zones. The higher the technical level is, the earlier the driver decelerates. Under the condition of light fog, the fog warning system with HMI has a better effect in terms of improving speed stability, while under the condition of heavy fog, there is little difference between the two technical levels. In general, this study proposed a novel safety evaluation index and a general evaluation method of the fog warning system.

Design and aerodynamic analysis of an Automotive Adaptive Rear Diffuser

Traditional vehicles are designed to bring out the best performance, good fuel economy, fewer emissions, and good high-speed stability. In this process of designing a vehicle, the underbody geometry of a car plays a vital role and is often neglected because of its complicated design bits. Though the presence of uneven surfaces causes the layers of air to separate resulting in generating turbulence. This report is about designing an active rear diffuser of a car. The rear diffuser is an aerodynamic device that is installed in the end part of the underbody of a car. Diffuser now a day is quite a common aerodynamic device that is used in performance cars. The main moto of attaching a diffuser is to reduce the wake produced behind the car and help the streamlines to converge better. The prime focus of this study is to design an active rear diffuser that will not only help in providing great high-speed stability and aerodynamic efficiency but will also use the aerodynamic forces adversely to help the car stop faster and on its track. This is made possible first by understanding the effects of diffuser angle on the aerodynamic forces acting on the car. Further, to actually transform the computational values into a working model, an electronic circuit is designed which mimics the exact movement of the diffuser according to the speed and other driving conditions. Keywords: Adaptive, diffuser, automobile, aerodynamic, aerodynamic Drag, aerodynamic Lift

ANALYSIS OF PRINCIPLE DIMENSION AND SHAPE OF PURSE SEINERS IN AMBON ISLAND

Abstrak Purse seiners as a ship's main small pelagic fish Catcher is increasingly growing in number and size. In the last 5 years has been an increase in purse seine boats in Maluku by 20% and 15% of the overall operating in waters around the island of Ambon. Purse seiners tend to be made traditionally based on experience and not in accordance with the criteria of size comparison of a fish boat. It is very technical and operational feasibility of affect in this speed, stability and longitudinal strength . This research aims to calculate speed, tonnage (GT), the size of the principal as well as set the geometric shapes of purse seiners on the island of Ambon. The methods used in this research is a survey method by gathering primary and secondary data by making observations and measurements directly against the 32 purse seiners in Ambon island. Analysis and discussion is done through estimation the ship's speed by using the formula of Nomura, estimated tonnage (GT) using the Standard Fish Vessel Regulations by the Director-General of Fisheries Catch of Indonesia in 2004, the determination of the optimal size of the principal ship in the empirical formula by numerical – Traung and geometric forms of purse seiner . Estimation against speed (V) and the tonnage (GT) shows that the speed average (Vaverage) = 7.1 knots and tonnage average(GTaverage) = 22.4 tons. The calculation of the size of the principal ship by using empirical methods-numerical based on Traung equation with input of Vaverage and GTaverageindicates that the principal dimension is as follows: LBP = 15.8 meters; B = 4.8 meters; D = 2.2 meters and d = 1.9 meters and form coefficient as follows : CB = 0,6 ; CW = 0,7 ; CM = 0,97 ; CP = 0,62

Preload Optimization Method for Traveling-Wave Rotary Ultrasonic Motor

Preload optimization is very important for ultrasonic motors’ design and application. In this paper, a novel method for a traveling-wave rotary ultrasonic motor is proposed. Firstly, based on linear regression and the analytic hierarchy process (AHP), the mapping between the drive characteristics, mechanical characteristics, speed stability, and preload of the traveling-wave-type rotary ultrasonic motor was established. Then, the characteristic curves of stalling torque, no-load speed, maximum efficiency, and speed stability with the change of preload method were measured with a new test platform. Finally, three traveling-wave rotary ultrasonic motors with optimized preload were used in a cooperative manipulator for validation. The experimental results showed that when the preload was optimized from 200 N to 310 N, the stalling torque of the motor increased by 20.7%, the maximum efficiency increased by 15.3%, the standard deviation of the speed decreased by 53.8%, and the no-load speed decreased by 5.5%. Therefore, it can be seen that the new preload optimization approach can significantly improve the performance indexes of ultrasonic motors and meet the practical requirements of direct-drive cooperative manipulators in engineering applications. The new preload optimization method offers advantages in motor output performance compared to conventional methods.

Pressing speed stability control of a special ceramic roller bearing press based on fuzzy adaptive PID

A special ceramic roller bearing press (SCRBP) is developed to press two bearings efficiently and precisely at the same time. A speed control mathematical model of the bearing press is built to obtain stability bearing pressing speed. The fuzzy adaptive PID controller of the bearing pressing speed of SCRBP is designed. The simulation model is also built. Fuzzy adaptive PID control is compared with conventional PID control. By simulation analysis, the simulation results show that adjusting time of fuzzy adaptive PID control is short, and its overshoot is very small, almost coincides with the set pressing speed. Moreover, fuzzy adaptive PID is suitable for the pressing speed control of the bearing pressing speed system with step interference signal. The pressing stability speed is obtained by fuzzy adaptive PID control.