This paper presents an approach for detecting multiple persons from a mobile robot using a combination of depth and thermal information. Previous works were mainly based on RGB and thermal data, but in this work we pr...
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This paper presents an approach for detecting multiple persons from a mobile robot using a combination of depth and thermal information. Previous works were mainly based on RGB and thermal data, but in this work we present a system where we combine depth and thermal data for occlusion handling. First, a classifier is trained using thermal images of the human upper-body. This classifier is used to obtain the bounding box coordinates of human. Initial detection process in thermal image is used as an estimate of the position of a person. The depth image is later fused with the region of interest obtained from the thermal image. Using the initial bounding box, occlusion handling is performed to determine the final position of human in the image. The proposed method significantly improves human detection even under occlusion.
Multiaxial stress states are very common in engineering applications. To obtain a plane stress state in a material are used different experimental procedures. Biaxial tensile tests of cruciform specimens represent one...
Multiaxial stress states are very common in engineering applications. To obtain a plane stress state in a material are used different experimental procedures. Biaxial tensile tests of cruciform specimens represent one of the most versatile techniques with accurate results for a wide range of materials. Specimen geometry and size must be adapted to biaxial experiments that use devices attached to universal testing machine. Biaxial tensile tests are performed using cruciform specimens optimized by a numerical study through finite element analysis and a custom built attachable device developed. The results obtained show that the method proposed in this paper can be used with good results to characterize the behaviour of ductile materials.
In real life experience, machine and structure elements are subjected to complex loading history. Combined loading testes facilitate the understanding of materials behavior subjected to multiaxial stress state. In thi...
In real life experience, machine and structure elements are subjected to complex loading history. Combined loading testes facilitate the understanding of materials behavior subjected to multiaxial stress state. In this paper are presented experimental investigations used to evaluate the influence of an initial type of loading on material properties which will be subsequently tested through another load type. Initial tests are tension tests, by different elongations, and subsequent tests are torsion tests, until break. Circular cross section specimens will be used in these tests. Tension tests have been performed on a universal testing machine. Subsequently torsion tests have been conducted through an attachable device. It was found that the energy associated with plastic deformation obtained by subsequent torsional tests has the dominant influence on the material total plastic energy, although initial test was tension.
In this article, a step-walker robot is introduced. In recent years too many explorer and moving robots are designed and manufactured. These kinds of robots need a mechanism for climbing stairs or steps to explore and...
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As some studies show, the number of people over 65 years old increases constantly, leading to the need of solution to provide services regarding patient mobility. Diseases, accidents and neurologic problems affect hun...
As some studies show, the number of people over 65 years old increases constantly, leading to the need of solution to provide services regarding patient mobility. Diseases, accidents and neurologic problems affect hundreds of people every day, causing pain and lost of motor functions. The ability of using the upper limb is indispensable for a human being in everyday activities, making easy tasks like drinking a glass of water a real challenge. We can agree that physiotherapy promotes recovery, but not at an optimal level, due to limited financial and human resources. Hence, the need of robot-assisted rehabilitation emerges. A robot for upper-limb exercises should have a design that can accurately control interaction forces and progressively adapt assistance to the patients' abilities and also to record the patient's motion and evolution. In this paper a short overview of upper limb rehabilitation devices is presented. Our goal is to find the shortcomings of the current developed devices in terms of utility, ease of use and costs, for future development of a mechatronic system for upper limb rehabilitation.
Ankle injuries are amongst the most common injuries of the lower limb. Besides initial treatment, rehabilitation of the patients plays a crucial role for future activities and proper functionality of the foot. Traditi...
Ankle injuries are amongst the most common injuries of the lower limb. Besides initial treatment, rehabilitation of the patients plays a crucial role for future activities and proper functionality of the foot. Traditionally, ankle injuries are rehabilitated via physiotherapy, using simple equipment like elastic bands and rollers, requiring intensive efforts of therapists and patients. Thus, the need of robotic devices emerges. In this paper, the design concept and some modelling and simulation aspects of a novel ankle rehabilitation device are presented.
Tendon-driven mechanisms (TDMs) are mechanisms driven by more tendons than joints. This tendon redundancy is often used for changing the hardware compliance. In contrast, in this paper, the redundancy is used for copi...
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ISBN:
(纸本)9781479969241
Tendon-driven mechanisms (TDMs) are mechanisms driven by more tendons than joints. This tendon redundancy is often used for changing the hardware compliance. In contrast, in this paper, the redundancy is used for coping with unexpected tendon breaking. We analyze kinematics of a class of TDMs with asymmetrically spanned tendons and modify it to design a TDM that preserves the controllability even if at least one of the tendons is broken. We validate the proposed method to design several TDMs.
Common methods, such as Denavit-Hartenberg （D-H） method, cannot be simply used in kinematic analysis of special robots with hybrid hinge as it is difficult to obtain the main parameters of this method. Hence, a homo...
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Common methods, such as Denavit-Hartenberg （D-H） method, cannot be simply used in kinematic analysis of special robots with hybrid hinge as it is difficult to obtain the main parameters of this method. Hence, a homogeneous transformation theory is presented to solve this problem. Firstly, the kinematics characteristic of this special structure is analyzed on the basis of the closed-chain theory. In such a theory, closed chains can be transformed to open chains, which makes it easier to analyze this structure. Thus, it will become much easier to establish kinematics equations and get the solutions. Then, the robot model can be built in the Simmechanics （a tool box of MATLAB） with these equation solutions. It is necessary to design a graphical user interface （GUI） for robot simulation. After that, the model robot and real robot will respectively move to some spatial points under the same circumstances. At last, all data of kinematic analysis will be verified based on comparison between data got from simulation and real robot.
The name of amorphous metals is assigned to metals that have a non-crystalline structure, but they are also very similar to glass if we look into their properties. A very distinguished feature is the fact that amorpho...
The name of amorphous metals is assigned to metals that have a non-crystalline structure, but they are also very similar to glass if we look into their properties. A very distinguished feature is the fact that amorphous metals, also known as metallic glasses, show a good electrical conductivity. The extension of the limit state criteria for different materials makes this type of alloy a choice to validate the new criterions. Using a new criterion developed for biaxial and triaxial state of stress, the results are investigated in order to determine the applicability of the mathematical model for these amorphous metals. Especially for brittle materials, it is extremely important to find suitable fracture criterion. Mohr-Coulomb criterion, which is permitting a linear failure envelope, is often used for very brittle materials. But for metallic glasses this criterion is not consistent with the experimental determinations. For metallic glasses, and other high-strength materials, Rui Tao Qu and Zhe Feng Zhang proposed a failure envelope modeling with an ellipse in σ-τ coordinates. In this paper this model is being developed for principal stresses space. It is also proposed a method for transforming σ-τ coordinates in principal stresses coordinates and the theoretical results are consistent with the experimental ones.
This paper describes an assembly sequence planner able to generate feasible sequences for building a desired assembly. The assembly planner takes geometrical, physical and mechanical constraints into account. Moreover...
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This paper describes an assembly sequence planner able to generate feasible sequences for building a desired assembly. The assembly planner takes geometrical, physical and mechanical constraints into account. Moreover, the planner considers the feasibility of grasps during the planning process and takes into account work-cell specific constraints. The approach uses AND/OR-graphs for planning. The generation of such graphs is implemented by using a specialized graph cut algorithm that employs a dynamically changing priority queue. These graphs are further evaluated by considering the feasibility of grasping sub-assemblies and individual parts during the process. The grasp and the sequence planner are generic, hence the proposed solution can be applied to arbitrary assemblies of rigid parts. The system has been evaluated with different configurations obtained by the combination of standard item-profiles.
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