We describe the design of a special lower limb rehabilitation robot for leg patients and its operation. The lower limb rehabilitation robot is composed of linear motion mechanisms, links, a foot plate, a joint and two...
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ISBN:
(纸本)9789897583049
We describe the design of a special lower limb rehabilitation robot for leg patients and its operation. The lower limb rehabilitation robot is composed of linear motion mechanisms, links, a foot plate, a joint and two-axis force sensors. The links and the foot plate are rotated according to the linear motion mechanisms. The bending motions of the hip, knee, and ankle are performed. The designed rehabilitation robot was subjected to tests involving hip joint bending, knee joint bending, and ankle joint bending exercises, and the robot operated smoothly. Therefore, it can be concluded that the designed rehabilitation robot can be used on leg patients, for the three exercises stated above.
This paper presents a distributed control for the formation control of mobile manipulators. We use a mobile manipulator model that can be separated in a kinematic and a dynamic component. For the kinematic component (...
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ISBN:
(纸本)9789897583049
This paper presents a distributed control for the formation control of mobile manipulators. We use a mobile manipulator model that can be separated in a kinematic and a dynamic component. For the kinematic component (formation control), we propose a distributed containment algorithm with a smooth function to avoid the chattering phenomenon, which provides control actions applicable in real robots. For the dynamic component, a controller based on the compensation of the dynamic forces and torques is applied. The structure of the formation is given by: a group of virtual leaders, which are used as references and to delimit the physic boundaries, and a group of follower robots. The distribution of the followers is determined by a Laplacian matrix, which is built based on the desired positions of the robots inside the convex hull formed by the virtual leaders. To validate the designed controllers, a simulation of formation and tracking trajectory of 8 mobile manipulators is performed, considering as reference, a sinusoid in each coordinate axis.
The problem of network inference can be solved as a constrained matrix factorization problem where some sparsity constraints are imposed on one of the matrix factors. The solution is unique up to a scaling factor when...
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ISBN:
(纸本)9789897583049
The problem of network inference can be solved as a constrained matrix factorization problem where some sparsity constraints are imposed on one of the matrix factors. The solution is unique up to a scaling factor when certain rank conditions are imposed on both the matrix factors. Two key issues in factorising a matrix of data from some netwrok are that of establishing simple identifiability conditions and decomposing a network into identifiable subnetworks. This paper solves both the problems by introducing the notion of an ordered matching in a bipartite graphs. Novel and simple graph theoretical conditions are developed which can replace the aforementioned computationally intensive rank conditions. A simple algorithm to reduce a bipartite graph and a graph preprocessing algorithm to decompose a network into a set of identifiable subsystems is proposed.
Adolescent Idiopathic Scoliosis (AIS) is a deformity of spine which occurs during growth. This paper presents a novel method for simulation of a 2D and 3D trunk model and the adaptation of an existing parallel mechani...
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ISBN:
(纸本)9789897583049
Adolescent Idiopathic Scoliosis (AIS) is a deformity of spine which occurs during growth. This paper presents a novel method for simulation of a 2D and 3D trunk model and the adaptation of an existing parallel mechanism to design parallel joints that can be used to correct abnormal postures of the human spine affected by scoliosis. A 3D model of the system has been elaborated for simulation and design. Simulations results show that this mechanism is able to permit some bending motions of human torso, taking into account the specifications of forward, backward and left/right sideways bending amplitudes.
The propose of this work is to extract different features from surface EMG signals of forearm muscles such as MAV, RMS, NZC, VAR, STD, PSD, and EOF's. Signals are acquired through 8 channels from "Myo Armband...
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ISBN:
(纸本)9789897583049
The propose of this work is to extract different features from surface EMG signals of forearm muscles such as MAV, RMS, NZC, VAR, STD, PSD, and EOF's. Signals are acquired through 8 channels from "Myo Armband" sensor that is placed in the forearm of the human being. Then, identification and classification of 5 types of movements are done, including open hand, closed hand, hand flexed inwards, out and relax position. Classification of the movement is performed through machine learning and data mining techniques, using two methods such as Feedforward Neural Networks and Support Vector Machines. Finally, an analysis is done to identify which features extracted from the sEMG signals and which classification method present the best results.
Given the large flight envelope of vertical take-off and landing vehicles, and the nonlinear nature of multirotor aircraft, especially in aggressive maneuvering, nonlinear control strategies are often considered. Yet,...
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ISBN:
(纸本)9789897583049
Given the large flight envelope of vertical take-off and landing vehicles, and the nonlinear nature of multirotor aircraft, especially in aggressive maneuvering, nonlinear control strategies are often considered. Yet, most available solutions are model dependent and thus require a precise knowledge of the system dynamics, including the hard to model aerodynamics. This paper proposes a sensor-based approach to the problem. It considers a recent strategy based on incremental control and Nonlinear Dynamics Inversion (NDI), the Incremental Nonlinear Dynamics Inversion (INDI), to solve the attitude control problem of quadrotors. The INDI general formulation is presented. and then applied considering the attitude stabilization of a quadrotor. In order to apply the INDI solution to this case study, a linear predictor for the angular acceleration is provided. Simulation results demonstrate the robustness of this sensor-based approach to model-parameter uncertainties and wind disturbances. An analysis is also done regarding the tuning of INDI parameters and its sensitivity to the chosen sampling time.
Discrete time implementation of task-priority redundancy resolution using closed loop inverse kinematics with fixed sampling time may lead to discretization chatter. The chattering effect is due to switching between d...
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ISBN:
(纸本)9789897583049
Discrete time implementation of task-priority redundancy resolution using closed loop inverse kinematics with fixed sampling time may lead to discretization chatter. The chattering effect is due to switching between different closed loop behaviours whenever the corresponding external event has occurred. This effect causes high frequency oscillation with finite frequency and amplitude in both joint space motion and operational space motion which is highly undesired. In this paper, we propose a planning and filtering algorithm to improve the robustness of task-priority redundancy resolution without having the effect of chattering, while combining multiple closed loop behaviours. We also show how the null space projection in task- priority control affects the operational space motion while switching between the behaviours. To demonstrate the effectiveness of the proposed algorithm, three different case studies are presented for a planar mobile manipulator with holonomic constraint. The results confirm that the proposed algorithm eliminates the chatter and moves the end effector on a smooth trajectory.
This paper addresses the problem of vertical take-off and landing (VTOL) over a moving target in an inland water environment. The maneuvers are carried out by a multi-rotor unmanned aerial system (UAS) over a double-h...
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ISBN:
(纸本)9789897583049
This paper addresses the problem of vertical take-off and landing (VTOL) over a moving target in an inland water environment. The maneuvers are carried out by a multi-rotor unmanned aerial system (UAS) over a double-hulled watercraft unmanned surface vehicle (USV). The approach proposed employs a cascade PID control architecture and is then improved with Dynamic Movement Primitives (DMP). The results presented show that DMP can be used in combination with PID classical control for achieving a more safe and accurate VTOL maneuver.
In this paper, a novel human-robot shared control approach is proposed to solve the problem of semi-autonomous mobile robot navigation with the spatial constraints of maintaining reliable Wi-Fi connection. In particul...
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ISBN:
(纸本)9789897583049
In this paper, a novel human-robot shared control approach is proposed to solve the problem of semi-autonomous mobile robot navigation with the spatial constraints of maintaining reliable Wi-Fi connection. In particular, the presented approach benefits from using Gaussian Process Regression method to learn the distribution of indoor Wi-Fi signal strength (WSS) and to fuse it with the environmental occupancy probability. The resulting WSS-Occupancy hybrid map is further utilized for generating paths that prevent the robot from violating the spatial restriction. A shared control strategy is designed to implement the WSS-aware navigation behaviour. The approach is evaluated by both simulation and real-world experiments, in which the results validate the practicability and effectiveness of the approach.
A dual gradient method is used for solving quadratic programs resulting from a model predictive control problem in real-time control context. Evolution of iterates and residuals throughout iterations of the method is ...
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ISBN:
(纸本)9789897583049
A dual gradient method is used for solving quadratic programs resulting from a model predictive control problem in real-time control context. Evolution of iterates and residuals throughout iterations of the method is studied. In each iteration, the set of active inequality constraints whose corresponding components of the Lagrange multiplier are non-zero can be defined. It is found that the set of active constraints tends to stay constant through multiple iterations. Observing the decay of residuals for intervals where the set of active constraints is constant leads to interesting findings. For such an interval, the dual residual can be expressed in a base so that its components are decaying independently, uniformly, and at predictable rates. The base and the rates only depend on the system matrices and the set of active constraints. The calculated decay rates match the rates observed in numerical simulations of MPC control, which is shown for the AFTI-16 benchmark example.
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