the majority of the kinematics analysis carried out on the human body are usually available only for use in the sagittal plane. Limited studies were interested in this analysis in all three planes (sagittal, transvers...
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ISBN:
(纸本)9789897583049
the majority of the kinematics analysis carried out on the human body are usually available only for use in the sagittal plane. Limited studies were interested in this analysis in all three planes (sagittal, transverse, and frontal) where motions of all joints occur. the aim of this paper is to develop a new optimal kinematic analysis of human lower limbs in three-dimensional space for a rehabilitation end. the proposed approach is focused on optimizing the manipulability and the human performance of the human leg, as being a physiologically constrained three-link arm. the obtained forward kinematic model leads to define the feasible workspace of the human leg in the considered configuration. Using an effective optimization-based human performance measure that incorporates a new objective function of musculoskeletal discomfort, the optimal inverse kinematic (IK) model is obtained.
Minimum-time trajectories for applications where a geometric path is followed by a kinematically redundant robot's end-effector may yield economical improvements in many cases compared to conventional manipulators...
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ISBN:
(纸本)9789897581984
Minimum-time trajectories for applications where a geometric path is followed by a kinematically redundant robot's end-effector may yield economical improvements in many cases compared to conventional manipulators. While for non-redundant robots the problem of finding such trajectories has been solved, the redundant case has not been treated exhaustively. In this contribution, the problem is split into two interlaced parts: inverse kinematics and trajectory optimization. In a direct optimization approach, the inverse kinematics problem is solved numerically at each time point. therein, the manupulator's kinematic redundancy is exploited by introducing scaled nullspace basis vectors of the Jacobian of differential velocities. the scaling factors for each time point are decision variables, thus the inverse kinematics is solved optimally w.r.t. the trajectory optimization goal, i.e. minimizing end time. the effectiveness of the presented method is shown by means of the example of a planar 4R manipulator with two redundant degrees of freedom.
Humanoid robots are conceived to resemble the body and comportment of the human beings. Among the behavior repertoire, the possibility of executing visually-guided tasks is crucial for individual adaptation and relies...
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ISBN:
(纸本)9789897580406
Humanoid robots are conceived to resemble the body and comportment of the human beings. Among the behavior repertoire, the possibility of executing visually-guided tasks is crucial for individual adaptation and relies on the on-board sensory system. However, the research on walk and localization is far from conclusive. Given the difficulties in the processing of the visual feedback, some studies have treated the problem by placing external sensors on the environment;thus neglecting the corporal metaphor. Others, despite exploring on-board solutions;have relied on an extensive model of the environment, thus considering the system as an information processing unit, abstracted from a body. this work presents a methodology to achieve embodied localization to serve visually-guided walk. the solution leans on robust segmentation from monocular vision, ego-cylindrical localization, and minimal knowledge about stimuli in the environment.
this paper introduces a comparison of a linear and nonlinear one step predictive models that were used to describe the relationship between human emotional signal - excitement - as a reaction to a virtual 3D face feat...
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ISBN:
(纸本)9789897580390
this paper introduces a comparison of a linear and nonlinear one step predictive models that were used to describe the relationship between human emotional signal - excitement - as a reaction to a virtual 3D face feature - distance between eyes. An input-output model building method is proposed that allows building a stable model withthe least output prediction error. Validation was performed using the recorded signals of six volunteers and the following measures: prediction error standard deviation, relative prediction error standard deviation, and average absolute relative prediction error. Validation results of the models showed that both models predict excitement signal in relatively high prediction accuracy.
Ultra-wideband has been widely used for accurate wireless indoor localization systems due to accurate ranging measurement capability. there are several methods for ranging-based localization systems: iterative methods...
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Withthe emergence of Industry 4.0 and its highly re-configurable manufacturing context, the typical fixedposition grasping systems are no longer usable. this reality underlined the necessity for fully automatic and a...
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ISBN:
(纸本)9789897585227
Withthe emergence of Industry 4.0 and its highly re-configurable manufacturing context, the typical fixedposition grasping systems are no longer usable. this reality underlined the necessity for fully automatic and adaptable robotic grasping systems. Withthat in mind, the primary purpose of this paper is to join Machine Learning models for detection and pose estimation into an automatic system to be used in a grasping environment. the developed system uses Mask-RCNN and Densefusion models for the recognition and pose estimation of objects, respectively. the grasping is executed, taking into consideration boththe pose and the object's ID, as well as allowing for user and application adaptability through an initial configuration. the system was tested both on a validation dataset and in a real-world environment. the main results show that the system has more difficulty with complex objects;however, it shows promising results for simpler objects, even with training on a reduced dataset. It is also able to generalize to objects slightly different than the ones seen in training. there is an 80% success rate in the best cases for simple grasping attempts.
Mobile robots are becoming increasingly prevalent in a large variety of applications. the introduction of robots into more complex environments necessitates the development of more advanced sensor systems to facilitat...
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Utilisation of space manipulator mounted on the satellite is one the main methods for the proposed Active Debris Removal and On-Orbit Servicing missions. Precise numerical models of the manipulator's joint are ver...
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ISBN:
(纸本)9789897585227
Utilisation of space manipulator mounted on the satellite is one the main methods for the proposed Active Debris Removal and On-Orbit Servicing missions. Precise numerical models of the manipulator's joint are very important as its dynamics has a strong effect on the behaviour of the system including the base where it is mounted. One of aspects that can be considered is the extension of manipulator's dynamical equations with gear kinematic constraints. To achieve this goal, dynamical equations of motion for planar 3DoF free-floating manipulator with gear kinematic constraints are presented in this paper. Open-loop analysis is performed to form conclusions concerning the influence of the gear reduction ratio on space manipulator's dynamics. Torques required to perform end-effector straight line trajectory are evaluated using inverse dynamics path planning algorithm and then utilised as motor driving torques for different gear reduction ratios. It appears that the gear reduction ratio influences the system mass matrix nonlinearly causing the end-effector trajectory to deviate from the straight line. these deviations are already observed for relatively low gear reduction ratios.
Cerebrovascular accident or stroke is one of the major brain impairments that affects numerous people globally. After a unilateral stroke, sensory motor damages contralateral to the brain lesion occur in many patients...
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ISBN:
(纸本)9781479931262
Cerebrovascular accident or stroke is one of the major brain impairments that affects numerous people globally. After a unilateral stroke, sensory motor damages contralateral to the brain lesion occur in many patients. As a result, gait remains impaired and asymmetric. this paper describes and simulates a novel closed loop algorithm designed for the control of a lower limb exoskeleton for post-stroke rehabilitation. the algorithm has been developed to control a lower limb exoskeleton including actuators for the hip and knee joints, and feedback sensors for the measure of joint angular excursions. It has been designed to control and correct the gait cycle of the affected leg using kinematics information from the unaffected one. In particular, a probabilistic particle filter like algorithm has been used at the top-level control to modulate gait velocity and the joint angular excursions. Simulation results show that the algorithm is able to correct and control velocity of the affected side restoring phase synchronization between the legs.
We propose a flexible computer vision system using magnetic sensors. the system enables a flexible free scanning of a CCD camera and a laser slit using 3D magnetic sensors. Many numbers of views of each model from dif...
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ISBN:
(纸本)9789897580390
We propose a flexible computer vision system using magnetic sensors. the system enables a flexible free scanning of a CCD camera and a laser slit using 3D magnetic sensors. Many numbers of views of each model from different angles can be taken on measuring the configuration between a CCD camera and a laser slit projector simultaneously. the information of different views is combined to reconstruct the 3D object on a computer display. In this paper, the application for pipe measurement is introduced. Experimental results show the feasibility of our system.
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