Adaptive intelligent cascade control of a ball-riding robot for optimal balancing
and station-keeping
Omer Saleem Bhatti, Osama Bin Tariq, Aneeq Manzar and Ozair Ali Khan
department of electrical engineering, national University of computer and emerging sciences, Lahore, Pakistan
ABSTRACT
This paper presents an adaptive intelligent cascade control strategy to maintain the dynamic stability of a ball-riding robot (BRR). The four-wheeled mechanism beneath the robot body balances it on a spherical wheel. The BRR is modeled as a combination of two decoupled inverted pendulums. Therefore, two independent controllers are used to control its pitch and roll rotations. An incremental proportional–integral–derivative (PID) is implemented in the inner loop of the cascade to maintain the vertical balance. A generic PD controller is used in the outer loop to keep the station by controlling its spatial position. The controller parameters are automatically tuned via a fuzzy adaptation mechanism. The centers of fuzzy output membership functions are dynamically updated via an extended Kalman fiter (EKF). The proposed controller quickly responds to changes in system’s state and effctively rejects the exogenous disturbances. The results of real-time experiments are presented to validate the effctiveness of the proposed hybrid controller over the conventional classical controllers.
KEYWORDS
ball-riding robot; proportional–integral– derivative controller; incremental controller; fuzzy adaptation mechanism; extended Kalman fiter
Gait motion for naturally curving variously shaped corners
Yasuhiro Akiyamaa, Shogo Okamotoa, Hitoshi Todab, Takao Ogurab and Yoji Yamadaa
aDepartment of Mechanical Science and Engineering, Nagoya University, Nagoya, Japan; bMie Prefectural Police, Tsu, Japan
ABSTRACT
Modeling the curving motion of humans in actual environment is rarely done because of the complexity and variability of the turning motion. In this study, various gait motions, including straight, round corner, and circular walks, were recorded and analyzed using factor analysis. As a result, we successfully extracted several factors that represent turning motions, such as long stride motion, turning motion led by the inner leg, and turning motion led by the outer leg. In particular, we found that the natural curving motion, which is a motion that results when turning around a round corner, is widely and continuously distributed on the factor space. Although several typical stepping strategies were reported by related studies, we found that the stepping motion changes between straight and turning gaits in the factor space during natural curving motions. Thus, the classification of curving motion into several typical distinct stepping patterns is probably insufficient to understand the natural curving motion. Furthermore, natural curving motions that comprise circular curving motions that were believed to represent typical curving motions was not validated. On the other hand, this result also suggests the possibility of generating curving motions for a physical assistant robot by combining straight gait and circler curving motion.
KEYWORDS
Turning; gait motion; factor analysis; stepping strategy; physical assistant robot
Literature review and current trends on transfemoral powered prosthetics
Carlos M. Lara-Barriosa , Andrés Blanco-Ortegaa, Cesar H. Guzmán-Valdiviab and Karla D. Bustamante Vallesc
adepartment of Mechanical engineering, tecnológico nacional de México, centro nacional de inestigación y desarrollo tecnológico, cuernavaca, México; bdepartment of Mechatronics engineering, Universidad Politécnica de Zacatecas, Fresnillo, México; ccentro de investigación en bioingeniería A.c., chihuahua, México
ABSTRACT
Transfemoral amputation is a common amputation procedure for the human lower limbs. Passive, semi-active, and active prosthetic devices are usually prescribed to amputees in order to restore their quality of life (QOL) according to their abilities. From an engineering perspective, prosthetic and normal gait analysis, actuator technology, and biologic prosthetic control strategies are some of the current objects of study on active lower limb prosthetic design which aimed to reduce potential biomechanical disorders such as gait asymmetry or elevated metabolic cost due to the use of passive prosthetic devices. The main goal of active prosthetic design is to deliver prosthetic assistance at biological levels. This paper reviews the latest developments of semi-active and active prosthetics for transfemoral amputees; as well as the common design considerations and effiency assessments performed on active transfemoral prosthetics under development in recent years.
KEYWORDS
Active prosthetics; biomechanics; series elastic actuator (seA); gait analysis; electromyography
Mechanical design and control of i nflatable robotic arms for high positioning
accuracy
Hye-Jong Kima, Akihiro Kawamurab, Yasutaka Nishiokac and Sadao Kawamuraa
aDepartment of Robotics, Ritsumeikan University, Shiga, Japan; bFaculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan; cDepartment of Mechanical Systems Engineering, University of Shiga Prefecture, Hikone Shiga, Japan
ABSTRACT
In recent years, inflatable robotic arms have been developed so that physical contact with humans and working environments could be performed safety. In industry, there is a growing demand for safe industrial robots to collaborate with people and work in various environments. In general, however, the positioning accuracy of inflatable robotic arms has not been discussed. This paper proposes an inflatable link structure and a non-inflatable joint structure that could realize a high positioning accuracy for such robotic arms. This paper experimentally demonstrates that these structures can improve positioning accuracy. In addition to these structures, the joint torque characteristics of the inflatable robotic arms were investigated. In order to perform accurate motion control, a visual feedback control method was introduced for inflatable robotic arms. The mechanism and control system used in this paper can improve the positioning accuracy performance of inflatable robots. A 2- DOF inflatable robotic arm and a camera system were found to be able to achieve a high positioning accuracy (i.e. less than 1 mm).
KEYWORDS
Soft; high positioning accuracy; inflatable structure; visual feedback control; relative position error
