Showing 4 results for Wearable Robot
Hassan Zohoor, Safoora Tahmasebi,
Volume 16, Issue 12 (2-2017)
Abstract
In recent years, knee diseases are spread especially in elderly people. Since performing daily activities such as walking and running, the knee supports the weight of the body, there is more likely to be injured. This issue is more important for elderly people who have weak muscles and almost all elderly people suffer from knee pain. One way to help this people in order to move normally is to use a wearable device to aid the knee. In this article, a passive wearable robot will be designed to improve the strength of the elderly who suffers from the knee pain. The robot uses the compliance elements to increase the power of the knee joint in parts of a cycle. This robot will be developed based on a Stephenson II six-bar mechanism. Using this mechanism has the advantage of producing the similar motion to a knee. In other words, this mechanism produces the linear and rotational motions simultaneously. Additionally, more compliance elements can be added to improve the performance of the wearable robot. The optimal dimensions of the robot will be Through the kinematics analysis and also the derivation of the dynamics equations and the numerical validations of these equations, the performance of the robot will be considered. The performance of the robot mounted on the leg is compared with the human. Obtained results show that the less power is required when a wearable robot is used. This proves the merits of the designed robot to be used for the elderly.
Ali Asghar Mohammadi Nasrabadi, Farshid Absalan, Seyed Ali Akbar Moosavian,
Volume 17, Issue 5 (7-2017)
Abstract
Wearable robots are robots which are used for rehabilitation or augmentation by human. Recently, there has been an increasing interest in the development of wearable devices to assist elderly as well as patients, soldiers and many other persons for movement assistance and power augmentation. On the other hand, a realization of wearable robot which has the same degree of freedom of a human is not easy from considerations about a size and weight of device. This study is about a lower limb assist robot that consist of just an actuator on each of legs. In this paper after a brief review on wearable robots and their applications, a suitable design of robot which is named RoboWalk presented with inspiring from Honda weight compensation system. In the following kinematics and dynamics modeling of system presents with using of denavit-hartenberg parameters and validates with ADAMS software results. Results with high accuracy has been achieved. It’s necessary to evaluate main foundation of design of robot which is an assistant force in the direction of foot reaction force that has been achieved with the accuracy of 0.02 radians. finally effect of change in user’s weight, position of center of mass and friction of walking assistant robot component is examined in this study.
M. Khamar, M. Edrisi,
Volume 18, Issue 9 (12-2018)
Abstract
Recently, a vast variety of wearable robots with various applications, including rehabilitation, have been produced, but a very challenging part of exoskeleton designing which is its motion control system still requires further investigation to be completed. Due to the nonlinearity in the dynamics of human-exoskeleton, uncertainty in parameters, unmodeled or simplified structures, and external disturbances (such as interaction of exerted human forces and movements), the use of robust control strategies is inevitable. Thus, in this research, a nonlinear disturbance rejection observer was used to estimate all of those as total disturbances. Then, a fractional order backstepping sliding mode (FOBSC) was utilized for enhanced tracking plus a Linear Quadratic Regulator (LQR) method to optimize the convergence to the equilibrium points. The advantage of using LQR is the optimum selection of the control input, and the FOBSC guarantees the robustness of the controller against uncertainties and disturbances. The combination of fractional order theory and control methods causes less chattering in the human-exoskeleton interactions. Moreover, particle swarm algorithm was used in order to select the coefficients of the cost function of LQR. In order to calculate the effect of the exoskeleton on human muscles and bones, the human parameters and knee motions, OpenSim was used. Matlab was used to implement the control strategy through OpenSim. The proposed method was then compared with the normal backstepping, fractional order system and LQR methods. The results show the superiority of this method compared to the classical methods.
Faezeh Azimi, Sajad Ozgoli, Majid M. Moghaddam,
Volume 21, Issue 4 (3-2021)
Abstract
Hands are complex moveable organs of the human body. some reasons such as stroke can cause the hands disordering. These patients have problem doing their daily routines. Communication between human and robots lead to inventing devices to improving ability. This paper aims to design and prototype a portable wearable robot. This robot has been designed to facilitate the daily routines of patients who are not able to extend their hands. Researchers are facing challenges like high cost due to numerous actuators and innumerous sensors used to control the system. As the number of elements used to build the device increase, the ultimate weight of the device, also, grows, and practically it loses portability. According to the importance of portability of the robot and the need for long-term use by the user, device components with less weight are designed in this work. In this regard, in the introduced mechanism, a torque is applied to the lowest metacarpophalangeal joints simultaneously by only one electric operator; therefore, fingers are opened. The power transmission system is inspired from the hand tendon with the help of the cable length changes. Because of disturbances and nonlinearity of the system, sliding mode controller to minimize the error is designed. The results demonstrate that the joint angle converges to the desired angle, and the error tends to zero. Good results of the practical test, in addition to being low cost, and weight imply that we can trust the extensibility of this project.
