• Journal of the Institute of Convergence Signal Processing
• /
• v.7 no.4
• /
• pp.214-220
• /
• 2006

This paper presents the systematic isotropy analysis of a fully actuated caster wheeled omnidirectional mobile robot (COMR) with the steering link offset different from the wheel radius, which can be considered as the generalization of the previous analysis. First with the characteristic length introduced, the kinematic model of a COMR is obtained based on the orthogonal decomposition of the wheel velocities. Second, the necessary and sufficient conditions for the isotropy of a COMR are derived and examined to categorize there different groups, each of which can be dealt with in a similar way. Third, for each group, the isotropy conditions are further explored so as to identify four different sets of all possible isotropic configurations. Fourth, for each set the expressions of the isotropic characteristic length required for the isotropy of a COMR are elaborated.

• 한국기계연구소 소보
• /
• s.15
• /
• pp.5-17
• /
• 1985

Dynamics of railway vehicles are strongly influenced by the wheel/rail contact forces. Wheel/rail contact geometric characteristics are important parameters to determining wheel/rail contact forces. In general, geometric relations between wheel and rail are represented by nonlinear functions of the wheelset lateral excursion and the relative yaw angle. There are some analytical and experimental studies to show the influences of the wheelset lateral displacement on wheel/rail geometric relations. Recently radial steering bogie which is designed to have flexible yaw motions of wheelsets was developed to improve curve negotiation performance. The radial steering bogie makes it important problem to study the effects of wheelset yaw motion on wheel/rail geometric relations. This paper describes the method to analyze 3-dimensional wheel/rail contact geometry considering wheelset yaw motion and describes also some computer simulation results.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.3
• /
• pp.240-249
• /
• 2013

This paper discusses the maneuvering control algorithm based on all-wheel independent driving and steering control techniques for special purpose 6WD/WS vehicles. The maneuvering control algorithms considering superior dynamic characteristics of high power in-wheel motors and independent steering system are designed to perform driving, steering, vehicle stability, and fault tolerant control. The maneuvering controller applies sliding and optimal control theories considering optimal torque distribution and friction circle related to the vertical tire force. The fault tolerant control algorithm is applied to obtain the similar maneuverability to that of the non-faulty vehicle. The simulations using the Matlab/Simulink dynamics model and experiments using HIL simulator mounting the real controllers with the designed control algorithms prove the improved performances in terms of vehicle stability and maneuverability.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.4
• /
• pp.86-92
• /
• 2009

A driver-vehicle model means the integrated dynamic model that is able to estimate the steering wheel angle from the driver's desired path based on the dynamic characteristics of the driver and vehicle. Autonomous driving robot for factory automation has individual four-wheels which are driven by electronic motors. In this paper, the dynamic characteristics of several four-wheel steering systems with the simultaneously steerable front and rear wheels are investigated and compared by means of the driver-vehicle model. A diver-vehicle model is proposed by using the PID control to velocity and trajectory of control autonomous driving robot. To determine the optimum speed of a autonomous driving robot, steady-state circle simulation is carried out with the ADAMS program and MATLAB control model.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1996.06c
• /
• pp.1055-1062
• /
• 1996

A method for automatically driving paddy vehicles, such as rice transplanters, etc., straight ahead in a paddy field was investigated . The direction of such vehicles must be precisely controlled to do the operations as straight. However, the alignment of the from wheels becomes distorted due to the unevenness of the ground, preventing the vehicle form going straight. If the proper alignment of the front wheels is maintained , the vehicle can be driven straight ahead greater precision. To investigate the influence of the ground uneveness, the behavior of a paddy vehicle running over an obstacle was quantified. The left wheel ran over an obstacle on a flat concrete road surfaced. When the steering wheel was free, the front wheels were forced toward the left when vehicle went up the obstacle and toward the right when the vehicle went down it. The torsion of the wheel when the vehicle went down the obstacle was larger than that when it went up ,so it turned right 5 degrees. Sinc hydraulic control steering decreased the steering angle , it turned right 3 degrees. These results suggest that a vehicle can be driven straight ahead with high precision when the steering angle is changed in response to the direction and inclination of the vehicle . Such results were obtained in a paddy field tests.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.5
• /
• pp.719-726
• /
• 1997

The proportional pressure control valve having versatile functions and higher performance is an essential conponent in the open loop controlled rear wheel steering gear of the four wheel steering system in a passenger car. In this study, the authors suggest a new type of load pressure feedback mechanism which can make it easy to change the range of controlled pressure without changing the capacity of solenoid. The concept of suggested mechanism, composed of the pressure chamber with throttles in series, was described. The mathematical model was derived from the rear wheel steering gear consisting of a valve and a cylinder for the purpose of analyzing the valve characteristics. And the programme for computing the characteristic of the valve was developed. Experiments were performed to confirm the performance of the valve and computations were carried out to ascertain the usefulness of the developed programme. The results from computations fairly coincide with those from experiments. And the results from experiments and computations show that the performance of new valve was as good as that of the already developed one and the new valve has advantages such as the easiness of changing the range of controlled pressure and the decrease of power loss at neutral position without the decline of performance.

• The KIPS Transactions:PartA
• /
• v.17A no.1
• /
• pp.19-26
• /
• 2010

As standard of living is higher and aging society is coming, it is needed to develop transportation that is easy to use for weak person. To comply with the demands, it is started to make Bi-modal Tram that is on KRRI(Korea Railroad Research Institute)'s hands. This tram has to have good accessibility like bus, be low level from ground like subway, and park accurately so wheel chair's or passenger's foot can't fall into the gap. But Bi-modal Tram have long length, so it need development of All Wheel Steering System. The Bi-modal Tram that have all wheel steering system steer not only the first axle but also the second and third axle from the first axle or articulation angle, and velocity, and so on. At this study, we discuss AWS ECU's development process.

• Journal of IKEEE
• /
• v.23 no.3
• /
• pp.844-851
• /
• 2019

As wearable technology is becoming more common and a part of our lives, there have been many efforts to offer various smart services with wearable devices, such as motion recognition, safety of driving, and so on. In this paper, we present a method that exploits the 9-axis inertial sensors embedded in a smartwatch to identify whether the user is a vehicle driver or not and to estimate the steering wheel turning direction in the vehicle. The system consists of three components: (i) position recognition, (ii) driver recognition, and (iii) steering-wheel turning detection components. We have developed a prototype system for detecting user's motion with Arduino boards and IMU sensors. Our experiments show high accuracy in recognizing the driver and in estimating the wheel rotation angle. The average experimental error was $11.77^{\circ}$ which is small enough to perceiver the turning direction of steering-wheel.

• Journal of Sensor Science and Technology
• /
• v.27 no.2
• /
• pp.126-131
• /
• 2018

Unlike the hydraulic power steering (HPS) system, which operates by the high pressure of a fluid obtained from the engine power, the motor-driven power steering (MDPS) system uses an electric motor to steer the wheel without consuming engine power. To steer the wheel with an electric motor, a worm wheel and a worm gear rotating between the steering shaft and motor are required. Any imperfection during the construction of an MDPS system or in a composing part creates noise and vibration, which can be sensed by a driver. To solve the noise and vibration problems, each part must be designed to not resonate with other parts. In this work, we developed the measurement and analysis systems to obtain the noise and the vibration of an automobile MDPS system. A signal analyzer was equipped with a 96 kHz, 24-bit ADC and a 150 MHz digital signal processor. The predetermined threshold value of the vibration in the MDPS system was used to determine the pass/fail, and the results were displayed on the screen. Our system can be used in the fabrication line to swiftly determine any imperfections in the MDPS system construction.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.307-308
• /
• 2009