A. Paulo Moreira

High‐level programming and control for industrial robotics: using a hand‐held accelerometer‐based input device for gesture and posture recognition

Purpose – Most industrial robots are still programmed using the typical teaching process, through the use of the robot teach pendant. This is a tedious and time‐consuming task that requires some technical expertise, and hence new approaches to robot programming are required. The purpose of this paper is to present a robotic system that allows users to instruct and program a robot with a high‐level of abstraction from the robot language.Design/methodology/approach – The paper presents in detail a robotic system that allows users, especially non‐expert programmers, to instruct and program a robot just showing it what it should do, in an intuitive way. This is done using the two most natural human interfaces (gestures and speech), a force control system and several code generation techniques. Special attention will be given to the recognition of gestures, where the data extracted from a motion sensor (three‐axis accelerometer) embedded in the Wii remote controller was used to capture human hand behaviours. G...

Accelerometer-based control of an industrial robotic arm

Most of industrial robots are still programmed using the typical teaching process, through the use of the robot teach pendant. In this paper is proposed an accelerometer-based system to control an industrial robot using two low-cost and small 3-axis wireless accelerometers. These accelerometers are attached to the human arms, capturing its behavior (gestures and postures). An Artificial Neural Network (ANN) trained with a back-propagation algorithm was used to recognize arm gestures and postures, which then will be used as input in the control of the robot. The aim is that the robot starts the movement almost at the same time as the user starts to perform a gesture or posture (low response time). The results show that the system allows the control of an industrial robot in an intuitive way. However, the achieved recognition rate of gestures and postures (92%) should be improved in future, keeping the compromise with the system response time (160 milliseconds). Finally, the results of some tests performed with an industrial robot are presented and discussed.

CAD-based off-line robot programming

Traditional industrial robot programming, using the robot teach pendant, is a tedious and time-consuming task that requires technical expertise. Hence, new and more intuitive ways for people to interact with robots are required to make robot programming easier. The goal is to develop methodologies that help users to program a robot in an intuitive way, with a high-level of abstraction from the robot language. In this paper we present a CAD-based system to program a robot from a 3D CAD environment, allowing users with basic CAD skills to generate robot programs off-line, without stop robot production. This system works as a human-robot interface (HRI) where, through a relatively low cost and commercially available CAD package, the user is able to generate robot programs. The methods used to extract information from the CAD and techniques to treat/convert it into robot commands are presented. The effectiveness of the proposed method is proved through various experiments. The results showed that the system is easy to use and within minutes an untrained user can set up the system and generate a robot program for a specific task. Finally, the time spent in the robot programming task is compared with the time taken to perform the same task but using the robot teach pendant as interface.

High‐level robot programming based on CAD: dealing with unpredictable environments

Purpose – The purpose of this paper is to present a CAD‐based human‐robot interface that allows non‐expert users to teach a robot in a manner similar to that used by human beings to teach each other.Design/methodology/approach – Intuitive robot programming is achieved by using CAD drawings to generate robot programs off‐line. Sensory feedback allows minimization of the effects of uncertainty, providing information to adjust the robot paths during robot operation.Findings – It was found that it is possible to generate a robot program from a common CAD drawing and run it without any major concerns about calibration or CAD model accuracy.Research limitations/implications – A limitation of the proposed system has to do with the fact that it was designed to be used for particular technological applications.Practical implications – Since most manufacturing companies have CAD packages in their facilities today, CAD‐based robot programming may be a good option to program robots without the need for skilled robot ...

Robot path simulation: a low cost solution based on CAD

The benefits of robot simulation technology have been recognized by scientists and engineers, with applications ranging from simple robot path simulation to complete robotic cell layout simulation. Robot simulation is one of the essential elements of modern and agile manufacturing plants, as it allows to visualize and test a robotic system, even if it does not exist physically. High-growth industries and emerging manufacturing processes will increasingly depend on advanced robot technology such as robotic simulation. Robot path simulation is a very useful process to predict and pre-evaluate performance of robot programs generated off-line. This paper presents a simulation system where a relatively low cost and commercially available 3D CAD package is used as an interface to visualize/simulate pre-programmed robot paths. The developed system is intuitive and friendly, so that in a few minutes any user without knowledge of CAD and robot programming will be able to simulate robot paths and visualize it in a CAD environment. This way, this simulator can be useful for small and medium sized enterprises and for educational purposes. Three different experiments (simulation of robot motion/paths) are presented and discussed: a material handling task; a robot performing work in the footwear industry (shoes soles); and finally, the simulation of robot paths for a robot operating in a bending cell. The experimental results showed that the proposed system is flexible, easy to use and efficient. This paper also covers topics like how simulation makes robot programming easier, advantages and disadvantages of simulation in robotics, and the future trends in this field. Finally, the results of the experiments will be analyzed and discussed. The pros and cons of the system in relation to off-the-shelf robot simulation packages are analyzed.

A Flow-based Motion Perception Technique for an Autonomous Robot System

Visual motion perception from a moving observer is the most often encountered case in real life situations. It is a complex and challenging problem, although, it can promote the arising of new applications. This article presents an innovative and autonomous robotic system designed for active surveillance and a dense optical flow technique. Several optical flow techniques have been proposed for motion perception however, most of them are too computationally demanding for autonomous mobile systems. The proposed HybridTree method is able to identify the intrinsic nature of the motion by performing two consecutive operations: expectation and sensing. Descriptive properties of the image are retrieved using a tree-based scheme and during the expectation phase. In the sensing operation, the properties of image regions are used by a hybrid and hierarchical optical flow structure to estimate the flow field. The experiments prove that the proposed method extracts reliable visual motion information in a short period of time and is more suitable for applications that do not have specialized computer devices. Therefore, the HybridTree differs from other techniques since it introduces a new perspective for the motion perception computation: high level information about the image sequence is integrated into the estimation of the optical flow. In addition, it meets most of the robotic or surveillance demands and the resulting flow field is less computationally demanding comparatively to other state-of-the-art methods.

TRAJECTORY TRACKING FOR OMNI-DIRECTIONAL MOBILE ROBOTS BASED ON RESTRICTIONS OF THE MOTOR'S VELOCITIES

Abstract In this paper, we propose an algorithm that combine the restriction on motors velocities and the kinematic model of Omni-Directional mobile robots to improve the trajectorys following. The algorithm verifies the reference velocities of the robot and redefine them if necessary, in order to prevent possible saturation on motors velocities. Simulation results of the algorithm applied to an omnidirectional mobile robot are presented.

Enhancing dynamic videos for surveillance and robotic applications: The robust bilateral and temporal filter

Over the last few decades, surveillance applications have been an extremely useful tool to prevent dangerous situations and to identify abnormal activities. Although, the majority of surveillance videos are often subjected to different noises that corrupt structured patterns and fine edges. This makes the image processing methods even more difficult, for instance, object detection, motion segmentation, tracking, identification and recognition of humans. This paper proposes a novel filtering technique named robust bilateral and temporal (RBLT), which resorts to a spatial and temporal evolution of sequences to conduct the filtering process while preserving relevant image information. A pixel value is estimated using a robust combination of spatial characteristics of the pixels neighborhood and its own temporal evolution. Thus, robust statics concepts and temporal correlation between consecutive images are incorporated together which results in a reliable and configurable filter formulation that makes it possible to reconstruct highly dynamic and degraded image sequences. The filtering is evaluated using qualitative judgments and several assessment metrics, for different Gaussian and Salt-Pepper noise conditions. Extensive experiments considering videos obtained by stationary and non-stationary cameras prove that the proposed technique achieves a good perceptual quality of filtering sequences corrupted with a strong noise component.

CAD-based robot programming: The role of Fuzzy-PI force control in unstructured environments

More and more, new ways of interaction between humans and robots are desired, something that allow us to program a robot in an intuitive way, quickly and with a high-level of abstraction from the robot language. In this paper is presented a CAD-based system that allows users with basic skills in CAD and without skills in robot programming to generate robot programs from a CAD model of a robotic cell. When the CAD model reproduces exactly the real scenario, the system presents a satisfactory performance. On the contrary, when the CAD model does not reproduce exactly the real scenario or the calibration process is poorly done, we are dealing with uncertain (unstructured environment). In order to minimize or eliminate the previously mentioned problems, it was introduced sensory feedback (force and torque sensing) in the robotic framework. By controlling the end-effector pose and specifying its relationship to the interaction/contact forces, robot programmers can ensure that the robot maneuvers in an unstructured environment, damping possible impacts and also increasing the tolerance to positioning errors from the calibration process. Fuzzy-PI reasoning was used as a force control technique. The effectiveness of the proposed approach was evaluated in a series of experiments.

The SPIDERobot: A Cable-Robot System for On-site Construction in Architecture

The use of robots in architectural construction has been a research field since the 1980s. Driven by both productive and creative concerns, different systems have been devised based on large-scale robotic structures, mobile robotic units or flying robotic vehicles. By analyzing these approaches and discussing their advantages and limitations, this paper presents an alternative strategy to automate the building construction processes in on-site scenarios. The SPIDERobot is a cable-robot system developed to perform assembly operations, which is driven by a specific Feedback Dynamic Control System (FDCS) based on a vision system. By describing and illustrating this research work, the authors argue about the advantages of this cable robot system to deal with the complexity and the scale of building construction in architecture.