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Copyright of Journal of Computational Applied Mechanics is the property of University of Tehran and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Balancing of the overturning reaction torque (RT) in an in-line two-cylinder internal combustion engine with cranks oriented in one direction using centrifugal forces from two groups of counterweights located on the crankshaft and balancer shaft is considered. It is shown that there are limitations in balancing the RT associated with the layout of the balancer shaft. New schemes are proposed for placing a group of counterweights on the disks of two directly unconnected gears driven by a crankshaft and rotating at the same angular speed, but in the opposite direction, which ensures complete balancing of the first-order inertial forces of reciprocating moving masses and the optimal possible partial balancing of the RT. The balancing of the RT for internal combustion engines of this type are analyzed; and the feasibility of the proposed designs are confirmed. [ABSTRACT FROM AUTHOR]

Path tracking control is an important method for a Six-Degree-Of-Freedom Autonomous Underwater Vehicle to perform specific underwater tasks. Therefore, this paper investigates a dual-loop integral sliding mode control (DLISMC)-based tracking controller for an AUV with model uncertainties and external disturbances, and introduces a new reaction torque model for static compensation in order to improve the attitude control capability for AUVs when performing path tracking. In addition, the stability of tracking control law based on DLISMC is demonstrated using the Lyapunov function. Finally, numerical simulations are carried out on MATLAB 2016/Simulink and compared with the Proportion–Integral–Differential (PID) control commonly used in industry as well as the dual-loop Proportion–Integral–Differential (DLPID). Simulation results show that the DLISMC has a smaller tracking error, faster convergence speed, and more robustness against external disturbances and reaction torque. [ABSTRACT FROM AUTHOR]

Path tracking control is an important method for a Six-Degree-Of-Freedom Autonomous Underwater Vehicle to perform specific underwater tasks. Therefore, this paper investigates a dual-loop integral sliding mode control (DLISMC)-based tracking controller for an AUV with model uncertainties and external disturbances, and introduces a new reaction torque model for static compensation in order to improve the attitude control capability for AUVs when performing path tracking. In addition, the stability of tracking control law based on DLISMC is demonstrated using the Lyapunov function. Finally, numerical simulations are carried out on MATLAB 2016/Simulink and compared with the Proportion–Integral–Differential (PID) control commonly used in industry as well as the dual-loop Proportion–Integral–Differential (DLPID). Simulation results show that the DLISMC has a smaller tracking error, faster convergence speed, and more robustness against external disturbances and reaction torque.

A tri-copter unmanned aerial vehicle (UAV) with individually tilted main wings for various flight maneuvers is presented. In contrast to conventional tilt wing UAVs, thrust vectoring and control of the directions of main wing surfaces are attained by tilting main wings individually. Such individually tilted main wings allow more efficient maneuvers of the UAV. Even though the UAV is a tri-copter, it can compensate the reaction torque created by the tail motor by the individual control of the main wings. Few publications have appeared in the literature, dealing with tri-copter UAV with individually tilted main wings. Dynamic model of the UAV is established via the Newton-Euler formulation and effect of individual wing control is examined. The PID controller and PI controller for control of flight maneuvers are implemented and used for simulations and experiments. Results of simulations and experiments are presented for validation of flight performance of the UAV, including the roll rate 80% larger than that of the conventional UAV with ailerons as control surfaces.

Ultra-compact electric vehicles are becoming popular means of personal mobility. However, due to their small size, it is difficult to install an assist mechanism for steering operation in most of these vehicles. As a solution, the research team proposes the application of the steer-by-wire system (SBWS) to control the front tires of the vehicle without any mechanical connection. By changing the steering gear ratio and steering wheel reaction torque, SBWS can provide optimal operability and driving comfort. In this study, an experimental vehicle is equipped with SBWS and the steering reaction torque of the steering wheel based on the steering angle as feedback is adjusted. The experimental results show that changing the steering wheel reaction torque affects driver muscle burden. [ABSTRACT FROM AUTHOR]

Copyright of China Petroleum Machinery is the property of China Petroleum Machinery Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the reaction torque based satellite base reactionless control or base disturbance minimization of a redundant free-floating space robot. This subject is of vital importance in the study of the free-floating space robot because the base disturbance minimization will result in less energy consumption and prolonged control application. The analytical formulation of the reaction torque is derived in this article, and the reaction torque control can achieve reactionless control and satellite base disturbance minimization. Furthermore, we derive the reaction torque based control of the space robot for base disturbance minimization from both the non-strict task priority and strict task priority control strategy. The dynamics singularity in the proposed algorithm is avoided in this paper. Besides, a real time simulation system of the space robot under Linux/real time application interface (RTAI) is developed to verify and test the feasibility and reliability of the method. The experimental results demonstrate the feasibility of online reaction torque control of the redundant free-floating space robot. [ABSTRACT FROM AUTHOR]

With recent advances in technologies such as those of semiconductors and actuators, easy-to-control compact actuators have been actively applied in various fields such as factory automation and precision machining. In the automobile industry, major manufacturers and venture companies are also concentrating on electric vehicle development. Ultra-compact mobility vehicles, which exhibit an excellent environmental performance and are highly convenient for short-distance movement, are becoming popular. However, owing to cabin space limitations, it is difficult to mount systems such as power steering for assisting steering operations, and such systems are currently not installed in most ultra-compact mobility vehicles. Our research group focused on a steer-by-wire system that does not require a physical connection between the steering wheel and the wheels. Using this system, the steering wheel can be installed without any constraints, and the cabin layout can be easily changed. The reaction torque applied to the steering wheel can be expected to provide an optimum steering feel to each driver by controlling the reaction-force-generating actuator output. Drivers with different heights and arm lengths were then grouped, and arm model calculation and electromyogram measurements obtained during steering operations were used to examine the muscle burden experienced during driving owing to differences in the drivers’ physiques.

Although the spiral grooved opposed-hemisphere gas bearings have been widely applied in supporting the spin axis of inertial grade gyroscopes, the accurate prediction of the performance characteristics of the bearings is still very difficult because of their structural complexity. In this paper, the static characteristics of the bearings considering the coupling effects between the journal and two hemisphere bearings are obtained theoretically. The Reynolds equations modeling the journal and hemisphere bearings are solved simultaneously by the finite element method satisfying the continuous boundary conditions between these three bearings. The fluctuations of the bearing load and reaction torque caused by rotating grooves are shown and can be neglected at large number of grooves. The results show that neglecting the coupling effects between the journal and two hemisphere bearings will result in large discrepancies at high rotational speeds and large eccentricity ratios. And the hydrodynamic effect can be divided into two regions for spiral grooved gas bearings: the groove effect domain region and the converged wedge effect domain region. A parametric study provides efficient guidance for the optimal design of the opposed-hemisphere gas bearing. [ABSTRACT FROM AUTHOR]

Variable-gear-ratio steering, also known as active steering, is an advanced steering technology which enhances the driver's comfort and vehicle operability. However, one big problem, namely the unnatural reaction torque created by the variable actuator, restricts the further practical-use of the variable-gear-ratio steering. This paper proposes a control method to cancel the unnatural torque using a simple concept called friction relocation. Effectiveness of the method is experimentally confirmed using a hardware-in-the-loop simulator. [ABSTRACT FROM AUTHOR]

With recent advances in technologies such as those of semiconductors and actuators, easy-to-control compact actuators have been actively applied in various fields such as factory automation and precision machining. In the automobile industry, major manufacturers and venture companies are also concentrating on electric vehicle development. Ultra-compact mobility vehicles, which exhibit an excellent environmental performance and are highly convenient for short-distance movement, are becoming popular. However, owing to cabin space limitations, it is difficult to mount systems such as power steering for assisting steering operations, and such systems are currently not installed in most ultra-compact mobility vehicles. Our research group focused on a steer-by-wire system that does not require a physical connection between the steering wheel and the wheels. Using this system, the steering wheel can be installed without any constraints, and the cabin layout can be easily changed. The reaction torque applied to the steering wheel can be expected to provide an optimum steering feel to each driver by controlling the reaction-force-generating actuator output. Drivers with different heights and arm lengths were then grouped, and arm model calculation and electromyogram measurements obtained during steering operations were used to examine the muscle burden experienced during driving owing to differences in the drivers' physiques. [ABSTRACT FROM AUTHOR]