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To ensure efficient transportation of large space structures in the future, it has been suggested that they be transported in an unassembled and compact form and then assembled inorbit using space robots. Forces generated during open contact operations have to be taken into careful consideration so that structural components can be successfully acquired and assembled by the robot. Unlike ground-based...
In this paper, we study the problem of a formation of agents trying to achieve a desired stationary or moving collective centroid. The agents are assumed to be moving in a force field which is controlled externally. The stabilization of the collective centroid to a fixed desired location results in a balanced formation of the agents about that point. Similarly, the centroid of the system of agents...
In this research, we have designed and implemented recursive least squares (RLS) algorithm in master slave tracking on Geomagic® Touch™ (Phantom Omni) haptic device. RLS algorithm enables us to achieve optimal tracking in a teleoperation system in which the system parameters vary with time and the noise is weakly non-stationary. In our previous work on teleoperation, we employed Widrow's least mean...
A method to compute the optimal sail angle for an autonomous sailboat is proposed, which allows for maximizing the longitudinal velocity while maintaining safe sailing conditions by limiting the roll angle. A simplified 4-DOF dynamic model of the sailboat is used to obtain the roll dynamics and longitudinal sail force. From these expressions, we derive a cost function which depends on the thrust force...
Simplified models of the dynamics such as the linear inverted pendulum model (LIPM) have proven to perform well for biped walking on flat ground. However, for more complex tasks the assumptions of these models can become limiting. For example, the LIPM does not allow for the control of contact forces independently, is limited to co-planar contacts and assumes that the angular momentum is zero. In...
This work presents approaches for the estimation of quantities important for the control of the momentum of a humanoid robot. In contrast to previous approaches which use simplified models such as the Linear Inverted Pendulum Model, we present estimators based on the momentum dynamics of the robot. By using this simple yet dynamically-consistent model, we avoid the issues of using simplified models...
Highly dynamic tasks that require large accelerations and precise tracking usually rely on precise models and/or high gain feedback. While movement primitives allow for efficient representation of such tasks from demonstrations, the optimization of the required motor commands for systems with inaccurate dynamic models remains an open problem. To achieve accurate tracking for such tasks, we investigate...
Humanoid robots propel themselves and perform tasks by interacting with their environment through contact forces. Typically, nonuniqueness of these forces is dealt with by distributing them evenly between the contacts. In the present paper, we introduce strict prioritization in contact force distribution, to reflect situations when an application of certain contact forces should be avoided as much...
In rehabilitation, a robot is useful and effective for repetitive trainings. However, few rehabilitation robots have adaptability to personal difference. Therefore, an index for quantitative assessment of the difference is required to achieve the adaptability. In conventional research, a hand stiffness is used as one of the indeces, and a dynamic hand stiffness is measured only in 2 dimensions. Then,...
In recent years, different exoskeleton devices have been developed to provide the users with the mechanical power required in augmentation and rehabilitation applications. The exoskeleton control is one of the most challenging issues causes widely attention of researches during recent decade. Although different methods of control have been presented, there are several issues which have not been answered...
In this paper controlled motion of an unbalanced two-link mechanism is discussed. Taking into account that contact with the supporting surface imposes unilateral constraints on the mechanical system, a control system structure with multiple feedback loops is proposed. Proposed control system changes control strategy when mechanism loses contact with the supporting surface. The influence that nonlinearities...
This doctoral consortium paper discusses our research plans to conduct human motion analysis and articulated pose estimation to solve the problem of American Sign Language (ASL) recognition in videos and to enhance Human computer interaction during Robot-aided rehabilitation.
In this paper, position control of a robot's end effector, by proposing an estimation mechanism for the interaction force between robotic tools and a soft tissue is presented. The proposed approach is using an adaptive strategy to provide the estimated force for achieving convergence of position and velocity tracking errors to zero. Moreover, the global stability of the closed loop system, using a...
In this paper, the stability and tracking control problem of a task space nonlinear bilateral teleoperation system is addressed interacting with a unknown environment. The controllers consist of adaptive controller and nonlinear disturbance observer to deal with uncertain dynamic model of manipulators, environmental and operators forces, respectively, in the presence of time delay. In order to estimate...
Recently, the variety of devices and robots are available for recovering and rehabilitating human disorder patients. In this paper, simple and effective control method utilized for position-impedance control. This method consists of two parts, namely position control in free space and fuzzy impedance control in contact. First, kinematics and dynamics of general 6UPS are discussed. Then SimMechanics...
Teleoperation systems in the medical usage, allows a surgeon to perform a remote distance operation with or without magnification. There is an increasing need to provide telerobots with the ability to interact with unknown and hybrid environments to detect the abnormalities and also performing the diagnostic procedures. In such environments it is challenging to guarantee the whole system stability...
Nowadays, robotic solutions have become important applicable techniques in micro-precision agricultural systems. Robotic harvesters such as fruit shakers have been developed using planar mechanisms with high degree of complexity. In this study, an analytical model of forced vibration of fruit stem system is presented. So, the motion equations are solved to obtain the dynamic behaviour of system. Then,...
The main purpose of teleoperation in medical usage is to provide technical means to perform a desired task in patient' body. It is important to haptic feedback of sensitive and delicate environment to the surgeon hand's to improve task performance. The Kelvin-Voigt (KV) model for environment, due to physical contradiction is not suitable, but the Hunt-Crossley (HC) model is chosen because of its accuracy...
In this paper, we propose an inverse optimal design method of a distributed graphical formation control of multiple mobile robots, where the group of robots configures the desired formation and moves with the same group velocity under the undirected graph topology. The robots' dynamics and kinematics are considered in the design. Under the assumption of perfect angular velocity tracking, the proposed...
The human-robot physical interaction systems (HRpI), are platforms designed for the transmission of knowledge, from contact between a human kinesthetic, and a robotic device with inertial dynamic and tribological low. The dynamic of contact for the robotic system is modified to the inertial, gravitational forces and tribology (friction and mechanical vibrations); that represent uncertainty in the...
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