Joao Carvalho

Federal University of Uberlândia | UFU · Faculty of Mechanical Engineering (FEMEC)

In robotic field, manipulators with parallel architecture have inherent advantages in relation to serial manipulators in various applications, such as high stiffness, accurate positioning and high movement velocities. In this context, the determination of volume position is one of the most important aspects considered during the manipulator project...

A robotic structure consists of a kinematic chain composed by links that can be rigid or flexible, interconnected by joints. One of the outstanding problems in robotic design and operation is to estimate a robot behavior under the action of external loads. In particular, it is needed a standard procedure to obtain the stiffness performance through...

In engineering designed systems it is commonly considered that mathematical models, variables, and parameters are sufficiently reliable, i.e., there are no errors in modeling and estimation. However, the systems to be optimized can be sensitive to small changes in the designed variables causing significant changes in the objective function. Robust...

The most common approach used in modeling humanoid robots applies trigonometric expressions and Euler-angles for its description. Some problems of trajectory interpolation and singularity of motion representation are discussed and the dual quaternion representation is used as an alternative to avoid these problems and to obtain the models ensuring...

Although the legged robots are considered as the most versatile type due to their major capability of moving on uneven terrain, the studied robots have not yet much mobility. In general this lack of mobility is related to the high number of degrees of freedom that makes it difficult to solve their mathematical model and applying it to the control s...

Artigo Completo As estruturas robóticas são comumente divididas em estruturas seriais, paralelas e híbridas. A estrutura serial consiste de um elemento terminal, ligado a uma base por meio de uma cadeia cinemática única. Uma estrutura paralela por sua vez pode ser descrita como um mecanismo formado por um elemento terminal, ligado a uma base fixa p...

This paper deals with the stiffness analysis of multibody systems using the Matrix Structural Analysis—MSA. This methodology allows us to obtain the stiffness matrix of the structure from the stiffness properties of each element. First the MSA method is described and its application is detailed using an L-structure in order to make easy its underst...

Many theoretical and experimental studies have been carried out in order to develop autonomous robots to travel along telecommunication lines and power transmission lines to perform inspection and/or repair work. These robots can improve the efficiency, reduce labor and are expected to reduce the risks of accident of maintenance personnel. In spite...

The science of rehabilitation shows that repeated movements of human limbs can help the patient regain function in the injured limb. There are three types of mechanical systems used for movement rehabilitation: robots, cable-driven manipulators, and exoskeletons. Industrial robots can be used because they provide a three-dimensional workspace with...

The development of robotic devices to apply in rehabilitation process of human lower limbs is justified by the large number of people with lower limb problems due to stroke and/or accidents. In this paper is presented a cable-based parallel manipulator for lower limb rehabilitation which is composed by a fixed base and a moving platform that can be...

The science of rehabilitation shows that repeated movements of human limbs can help the patient regain function in the injured limb. There are three types of mechanical systems used for movement rehabilitation: robots, cable-based manipulators, and exoskeletons. Industrial robots can be used because they provide a three-dimensional workspace with a...

This paper presents the current state of the art in mobile robots used on power transmission lines. Many theoretical and experimental studies have been conducted in order to develop autonomous machines to travel along transmission lines to perform inspection and/or repair work. These machines can improve efficiency, reduce labour costs and are expe...

The development of robotic devices to apply in the rehabilitation process of human lower limbs is justified by the large number of people with lower limb problems due to stroke and/or accidents. Thus, this paper presents a cable-driven parallel manipulator for lower limb rehabilitation which is composed by a fixed base and a mobile platform that ca...

In this paper a cable-based system is presented for rehabilitation of the wrist movements. The proposed structure consists of one or two cables that allow the movement of abduction-adduction and flexion-extension with different limits of movement and speed. The development of this robotic device is justified by the large number of people with upper...

Vibratory feeders or vibratory conveyors have been widely used for the transport and orientation of individual parts and bulk materials in many branches of industrial activity. From the designer's standpoint, the current endeavor is to conceive efficient vibratory feeders, satisfying constraints of power consumption, vibration transmission and nois...

The science of rehabilitation shows that repeated movements of human limbs can help the patient regain function in the injured limb. There are three types of mechanical systems used for movement rehabilitation: robots, cable-based manipulators, and exoskeletons. Industrial robots can be used because they provide a three-dimensional workspace with a...

In this paper a simulation of movements of lumbar spine is proposed by using a model with serially connected parallel manipulators. An analysis has been computed for the human spine structure and its movements, in order to simulate the motions and forces that actuate a spine specifically in the lumbar segment. A mechanical model has been designed w...

In this paper a cable-based system is presented for rehabilitation of the shoulder and elbow movements. Cable-based manipulators have very good kinematic and dynamic characteristics, and they also show other properties such as: transportability and low-cost construction, which make them also suitable for medical applications and rehabilitation. The...

This paper presents a historical record regarding ABCM – Brazilian Society of Engineering and Mechanical Sciences, its relationship with IFToMM and its important role in engineering and mechanical sciences in Brazil.

This work presents a mobile robot that moves suspended on transmission lines and/or telecommunication transmission lines, which can transpose signalizing spheres and sustaining insulators, placed at any position on wire. The use of multi body systems software helped in the development of the prototype allowing to visualize the three-dimensional beh...

In this paper, a novel algorithm is formulated and implemented for optimum path planning of parallel manipulators. A multi-objective optimisation problem has been formulated for an efficient numerical solution procedure through kinematic and dynamic features of manipulator operation. Computational economy has been obtained by properly using a genet...

In this paper we have presented an analytical model for the dynamics of a CaPaMan (Cassino Parallel Manipulator). The peculiar kinematic chain and symmetry properties of CaPaMan architecture have been useful to formulate the Newton–Euler equations in a closed-form in order to compute the input torques, which are necessary for a given motion traject...

We report results of successful experiences using CaPaMan (Cassino Parallel Manipulator) as an earthquake simulator. The paper describes the experimental set up for a sensored mobile plate for verifying the numerical simulations with practical experiments. Reproducing accelerometer diagrams of actual earthquakes has proved a practical feasibility....

Using the isostatic position of Kelvin, we shall develop a new parallel robot having six degrees of freedom, with the axes of the actuators placed two by two along the three axis of a cartesian reference system. For this purpose, we shall use the method of binarised torsors. The solution obtained has many advantages: it is perfectly homogenous, it...

This paper describes a stiffness analysis of a 6-RSS parallel architecture by using matrix structural analysis. The stiffness analysis is based on standard concepts of static elastic deformations. The formulation has been implemented in order to obtain the stiffness matrix that can be numerically computed by defining a suitable model of the manipul...