Robot kinematics

This paper concerns the problem of actively searching for and localizing ground features by a coordinated team of air and ground robotic sensor platforms. The approach taken builds on well known Decentralized Data Fusion (DDF) methodology. In particular, it brings together established representations developed for identification and linearized estimation problems to jointly address feature detection and localization. This provides transparent and scalable integration of sensor information from air and ground platforms. As in previous studies, an Informationtheoretic utility measure and local control strategy drive the robots to uncertainty reducing team configurations. Complementary characteristics in terms of coverage and accuracy are revealed through analysis of the observation uncertainty for air and ground on-board cameras. Implementation results for a detection and localization example indicate the ability of this approach to scalably and efficiently realize such collaborative potential.

This paper describes a Virtual Reality (VR) based system for automating data collection and surveying in a retail store using mobile robots. The manpower cost for surveying and monitoring the shelves in retail stores are high, because of which these activities are not repeated frequently causing reduced customer satisfaction and loss of revenue. Further, the accuracy of data collected may be improved by avoiding human related factors. We use a mobile robot platform with on-board cameras to monitor the shelves either autonomously or through tele-operation. A remote operator can control the robot from a console which shows a 3D of view of the store as well as, capture real images and videos of the store. The robot is designed to facilitate automatic detection of Out-of-Stock (OOS) situations. It would be possible for a single operator to control multiple robots placed at different stores thus optimizing the available resources. As the deployment of the proposed system does not require...

Formations of multi-agent systems, such as satellites and aircraft, require that individual agents satisfy their kinematic equations while constantly maintaining inter-agent constraints. In this paper, we develop a systematic framework for studying formations of multiagent systems. In particular, we consider undirected formations for centralized formations and directed formations for decentralized formations. In each case, we determine differential geometric conditions that guarantee formation feasibility given the individual agent kinematics. Our framework also enables us to extract a smaller control system that describes the formation kinematics while maintaining all formation constraints.

Cooperative mobile robots have recently been gaining importance within the field of robotics. It's been proven that collaborative robots can do tasks in a faster and more reliable manner than a single robot can. Additionally, recent advances in distributed coordination algorithms have dramatically improved the feasibility and suitability of cooperative approaches. This has lead researchers to develop Inter-robot communication frameworks. While several frameworks have been introduced, one of the most common is the Service-Oriented Architecture (SOA). However, the suitability of SOA for collaborative robotic communication has not been fully evaluated. In this paper we evaluate the SOA from an overhead perspective against non service-based architectures in a wireless environment. Our evaluation is based on performance suitability, which is determined by measuring throughput and delay for different numbers of mobile robots sharing real time data.

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In open systems where the components, i.e. the agents and the resources, may be unknown at design time, or in dynamic and self-organizing systems evolving with time, there is a need to enable the agents to communicate their intentions with respect to future activities and resource utilization to resolve coordination issues dynamically. Ideally, we would like to allow ad-hoc interaction, where two standalone independently-designed systems are able to coordinate whenever a need arises. The Semantic Web based approach presented in this paper aims at enabling agents to coordinate without assuming any design-time ontological alignment of them. An agent can express an action intention using own vocabulary, and through the process of dynamic ontology linking other agents will be able to arrive at a practical interpretation of that intention. We also show how our approach can be realized on top of the Semantic Agent Programming Language.

The basic principles in engineering mechanics and robotic courses such as kinematics or rotation matrices have the reputation of being difficult and primarily of academic interest. Thus many students consider those courses simply as annoying prerequisites to subsequent engineering courses, resulting in low levels of motivation. But instead of repeating the same topic over and over, a student-centered learning unit is presented. In the new developed study course the experimental work exemplifies the practical benefit of seemingly abstract concepts using the humanoid NAO robot, solving tasks, e.g. the “throwing of a ball”. This simple “human activity” is a complex programming task in humanoid robotics, considering not only the construction, the static and the dynamic stability of the robot but also planning the robot’s behaviour and the human-robot interaction.

Utilizing robots does not only enhance the acquisition of subject-related knowledge, but also fosters meta-disciplinary competences like spatial sense, logical reasoning, and self-learning ability. Finally, the robot-enhanced learning unit allows for an individualization of the learning process, increasing students' involvement and motivation. The presented learning unit is student-centered in the sense that participants construct an understanding of the covered material in an active, collaborative way following the famous saying “Tell me, and I will forget. Show me, and I may remember. Involve me, and I will understand”, occasionally attributed to Confucius. The experiences gained in the presented study course facilitates the development of an interactive learning tool with respect to gender and diversity aspects.

This paper presents a new solar arrays deployment mechanism for space applications. It consists of a modular kinematic structure, which is operated by a single cable (1 DoF). Compared to traditional methods, this mechanism has the advantage of being reversible in the movement. Kinematic analysis of the mechanism is carried out in this work, as well as static analysis. They allow to define the main actuation parameters such as cable pull tension and spring stiffness. Moreover, suitable values for the mechanism parameters are computed by means of a dedicated algorithm.

Due to its environmental, economical and safety implications, methane leak detection is a crucial task to address in the biogas production industry. In this paper, we introduce Gasbot, a robotic platform that aims to automatize methane emission monitoring in landfills and biogas production sites. The distinctive characteristic of the Gasbot platform is the use of a Tunable Laser Absorption Spectroscopy (TDLAS) sensor. This sensor provides integral concentration measurements over the path of the laser beam. Existing gas distribution mapping algorithms can only handle local measurements obtained from traditional in-situ chemical sensors. In this paper we also describe an algorithm to generate 3D methane concentration maps from integral concentration and depth measurements. The Gasbot platform has been tested in two different scenarios: an underground corridor, where a pipeline leak was simulated and in a decommissioned landfill site, where an artificial methane emission source was int...

We present a generic algorithm for self calibration of robotic systems that utilizes two key innovations. First, it uses information theoretic measures to automatically identify and store novel measurement sequences. This keeps the computation tractable by discarding redundant information and allows the system to build a sparse but complete calibration dataset from data collected at different times. Second, as the full observability of the calibration parameters may not be guaranteed for an arbitrary measurement sequence, the algorithm detects and locks unobservable directions in parameter space using a truncated QR decomposition of the Gauss-Newton system. The result is an algorithm that listens to an incoming sensor stream, builds a minimal set of data for estimating the calibration parameters, and updates parameters as they become observable, leaving the others locked at their initial guess.

Developing easy to use, intuitive interfaces is crucial to introduce robotic automation to many small medium sized enterprises (SMEs). Due to their continuously changing product lines, reprogramming costs exceed installation costs by a large margin. In addition, traditional programming methods for industrial robots is too complex for an inexperienced robot programmer, thus external assistance is often needed. In this paper a new incremental multimodal language, which uses augmented reality (AR) environment, is presented. The proposed language architecture makes it possible to manipulate, pick or place the objects in the scene. This approach shifts the focus of industrial robot programming from coordinate based programming paradigm, to object based programming scheme. This makes it possible for non-experts to program the robot in an intuitive way, without going through rigorous training in robot programming.

The aim of the development was the construction of a freely programmable handling system for use as an experimental plant for various tasks in research and development in the field of overground workings where freely programmable movement and force patterns are important. The system should be suitable for building assembly work in particular. With regard to the robot technology and the assembly operations, plans which are worked out theoretically are checked here and developed further by practical experience.

This paper presents a software architecture required to build a user-friendly interface for a robot manipulator. For this purpose, during research a prototype 5-DOF robotic arm was built. The end effector of this robotic arm is a two-fingered gripper. The interface consists of two components generic to most industrial robot systems present today, first is the teach-pendant and second one is the computer based robot programming language. The main focus of the project is to develop a Language that provides robot-specific commands along with the framework common to all high level languages. A user interface has been developed that provides powerful tools for efficient control of the robot manipulator. The aspiration of this work is to present a system which is powerful, cost effective and at the same time intelligible to an average user.

This paper addresses the problem of path generation and motion control for the autonomous maneuver of a farm vehicle with a trailed implement in headland. A reverse turn planner is firstly investigated, based on primitives connected together to easily generate the reference motion. Then, both steering and speed control algorithms are presented to accurately guide the vehicle-trailer system. They are based on a kinematic model extended with additional sliding parameters and on model predictive control approaches. Real world experiments have been carried out on a low friction terrain with an experimental mobile robot pulling a trailer. At the end of each row, the reverse turn is automatically generated to connect the next reference track, and the maneuver is autonomously performed by the vehicle-trailer system. Reported experiments demonstrate the capabilities of the proposed algorithms.

This paper focuses on time-optimal and time-energy optimal path tracking, which are subproblems in optimal motion planning of robot systems. Through a nonlinear change of variables, the time-energy optimal path tracking problem is transformed here into a convex optimal control problem with a single state variable. A direct transcription method is presented that reduces finding the globally optimal trajectory to solving a second-order cone program using robust numerical algorithms that are freely available. Application to a six-DOF KUKA 361 industrial robot carrying out a writing task illustrates the practicality of the new method.

In this study, a Best First Search (BFS) Based Intelligent PID Tuning Method is proposed for a mobile robot path tracking problem. BFS is an informed search strategy in Artificial Intelligence (AI). It has been used in many areas of intelligent systems. Here, it is used to search values of both ultimate period and ultimate gain of Ziegler-Nichols (ZN) PID Tuning Method. So, using these ultimate period and gain, PID parameters can be c from tables of ZN method. The performance measure in this problem is described as minimizing total error during any specified trajectory tracking. Thus the proposed method does not depend on the system model. It only needs error information during the tracking control. So, this method can be used to tune PID parameters of any tracking controller for a system with unknown system dynamics. The proposed method is tested with simulations in MATLAB during trajectory tracking of a mobile robot. In addition, it is compared with classical PID and conventional PID tuning methods including Ziegler-Nichols method, Tyreus-Luyben method, and Shinskey method.

Keywords: Intelligent PID tuning, best first search, autonomous mobile robot, mobile robot path tracking problem, computed torque PID control, dynamic model, Ziegler-Nichols, Tyreus-Luyben, Shinskey.

We propose a novel approach for dynamically simulating articulated rigid bodies undergoing frequent and unpredictable contact and collision. In order to leverage existing algorithms for nonconvex bodies, multiple collisions, large contact groups, stacking, etc., we use maximal rather than generalized coordinates and take an impulse-based approach that allows us to treat articulation, contact, and collision in a unified manner. Traditional constraint handling methods are subject to drift, and we propose a novel prestabilization method that does not require tunable potentially stiff parameters as does Baumgarte stabilization. This differs from poststabilization in that we compute allowable trajectories before moving the rigid bodies to their new positions, instead of correcting them after the fact when it can be difficult to incorporate the effects of contact and collision. A poststabilization technique is used for momentum and angular momentum. Our approach works with any black box method for specifying valid joint constraints and no special considerations are required for arbitrary closed loops or branching. Moreover, our implementation is linear both in the number of bodies and in the number of auxiliary contact and collision constraints, unlike many other methods that are linear in the number of bodies, but not in the number of auxiliary constraints.

This paper presents the 25-DOF full-size humanoid robot LOLA. Our goal is to realize fast and human-like walking. Furthermore, we want to increase the robot's autonomous, visionguided walking capabilities. LOLA is characterized by a redundant kinematic configuration, an extremely lightweight design, joint actuators with brushless motors and an electronics architecture using decentralized joint control. Special emphasis was put on an improved mass distribution to achieve good dynamic performance. Center of mass trajectories are calculated in real-time from footstep locations using a spline collocation method. Reference trajectories are modified by a stabilizing control system based on hybrid force/position control with an inner joint position control loop.

This paper proposes a simple, reactive algorithm for real time obstacle avoidance, aimed to be implemented on low cost, low power microcontrollers. According to this algorithm, the robot reacts to obstacles detected within an area called “sensitivity bubble”, whose shape and size are dynamically adjusted, depending on the kinematics of the robot. Upon detection of an obstacle, the robot “rebounds”

This paper develops the applicability of using fuzzy logic controller and incorporates it with other heuristics strategy for robots to play soccer. In this system, fuzzy logic is used to control the motion of the robots. It will generate velocities and feed these velocities to the respective robot motor. In addition, heuristic approach will be used for cooperative behavior as well as other strategies necessary for the robots to win in a particular robot soccer game.

In this project we are brougth to construct a unicycle robot to control it. using the cinematic modeling of the unicycle robot under MATLAB / SIMULINK we succeeded to characterize and enslave our system while controlling it in speed and CAP. Then, using the graphical interface V-REP we developed the prototype of the robot. Then we succeeded in communicating the environment MatlAb / Simulink with the graphical interface V-REP, this allowed us to control our robo
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If you have any questions about this project, do not hesitate to contact me on my email address

e-mail : [email protected]

good reading!

{ Whenever a sensor is mounted on a robot hand it is important t o k n o w the relationship between the sensor and the hand. The problem of determining this relationship is referred to as the hand-eye calibration problem. Hand-eye calibration is important in at least two types of tasks: (i) map sensor centered measurements into the robot workspace frame and (ii) allow the robot to precisely move the sensor. In the past some solutions were proposed in the particular case of the sensor being a TV camera. With almost no exception, all existing solutions attempt to solve a homogeneous matrix equation of the form AX = X B . This paper has the following main contributions. First we show that there are two possible formulations of the hand-eye calibration problem. One formulation is the classical one that we just mentioned. A second formulation takes the form of the following homogeneous matrix equation: M Y= M 0 Y B . The advantage of the latter formulation is that the extrinsic and intrinsic parameters of the camera need not be made explicit. Indeed, this formulation directly uses the 3 4 perspective matrices (M and M 0 ) associated with 2 positions of the camera with respect to the calibration frame. Moreover, this formulation together with the classical one cover a wider range of camera-based sensors to be calibrated with respect to the robot hand: single scan-line cameras, stereo heads, range nders, etc. Second, we develop a common mathematical framework to solve for the hand-eye calibration problem using either of the two formulations. We represent rotation by a unit quaternion. We present two methods, (i) a closed-form solution for solving for rotation using unit quaternions and then solving for translation and (ii) a non-linear technique for simultaneously solving for rotation and translation. Third, we perform a stability analysis both for our two methods and for the classical linear method developed by Tsai & Lenz TL89]. This analysis allows the comparison of the three methods. In the light of this comparison, the non-linear optimization method, that solves for rotation and translation simultaneously, seems to be the most robust one with respect to noise and to measurement errors.

The paper proposes a kinematic approach for tracked vehicles in order to improve motion control and pose estimation. Complex dynamics due to slippage and soil shearing make it difficult to predict the exact motion of the vehicle from the velocity of the two tracks. Nevertheless, reliable geometric approximations are necessary to perform onboard real-time computations for autonomous navigation. The presented solution is based on the kinematic similarities between tracked vehicles and wheeled differential drive vehicles. Particularly, the approximate position of wheel contact points for an equivalent vehicle can be optimized for a particular terrain at moderate speeds. This is achieved off-line by feeding a genetic algorithm with raw trajectory data and reliable localization estimations based on external sensors. The method has been successfully tested for online odometric computations and low-level motion control with the Auriga-α mobile robot. Moreover, the identified parameters are similar to those obtained from the simulated stationary response of a complex dynamic model of this vehicle.

Report from Modelling in Robotics course. Information about KUKA youBot kinematic equations along with the implementation in Simulink is provided. This document pretends to give an idea on how such system should be modeled and a possible implementation.

Abstract— This paper describes the design and development of hexapod robot with three degrees of freedom (3 DOF) at each leg. The system developed is composed of the mechanical assembly, the circuits used to control the servomotors (Digital Signal Controller - DSC) ...

The complexity of walking robots poses a number of control problems due to the large number of degrees of freedom involved in the robot's motion. This work deals with the design of a hexapod robot, whose legs have 3 rotative joints and the same configuration. The kinematics ...

An "ideal" upper limb prosthesis should be perceived as part of the natural body by the amputee and should replicate sensory-motor capabilities of the amputated limb. However, such an ideal "cybernetic" prosthesis is still far from reality: current prosthetic hands are simple grippers with one or two degrees of freedom (DOF), which barely restore the capability of the thumbindex pinch. This paper describes the development of a novel prosthetic hand based on a "biomechatronic" design. The proposed hand is designed to augment the dexterity of traditional prosthetic hands while maintaining approximately the same dimension and weight. Our approach is aimed at providing enhanced grasping capabilities and "natural" sensory-motor coordination to the amputee, by integrating miniature mechanisms, sensors, actuators, and embedded control. A biomechatronic hand prototype with three fingers and a total of six independent DOFs has been designed and fabricated. The paper is focused on the actuators system, which is based on miniature electromagnetic motors.

We present an implementation of a reinforcement learning algorithm through the use of a special neural network topology, the AHC (adaptive heuristic critic). The AHC is used as a fusion supervisor of primitive behaviors in order to execute more complex robot behaviors, for example go to goal, surveillance or follow a path. The fusion supervisor is part of an architecture for the execution of mobile robot tasks which are composed of several primitive behaviors which act in a simultaneous or concurrent fashion. The architecture allows for learning to take place at the execution level, it incorporates the experience gained in executing primitive behaviors as well as the overall task. The implementation of this autonomous learning approach has been tested within OPMOR, a simulation environment for mobile robots and with our mobile platform, the UPM Robuter. Both, simulated and actual results are presented. The performance of the AHC neural network is adequate. Portions of this work has been implemented within the EEC ESPRIT 2483 PANORAMA Project

A new technique for three-dimensional (3D) camera calibration for machine vision metrology using off-the-shelf TV cameras and lenses is described. The two-stage technique is aimed at efficient computation of camera external position and orientation relative to object reference coordinate system as well as the effective focal length, radial lens distortion, and image scanning parameters. The two-stage technique has advantage in terms of accuracy, speed, and versatility over existing state of the art. A critical review of the state of the art is given in the beginning. A theoretical framework is established, supported by comprehensive proof in five appendixes, and may pave the way for future research on 3D robotics vision. Test results using real data are described. Both accuracy and speed are reported. The experimental results are analyzed and compared with theoretical prediction. Recent effort indicates that with slight modification, the two-stage calibration can be done in real time.

Robots are one of the most representative fields in mechatronics, this article presents the development process of a mechatronic system, taking into account 3 DOF parallel robots, pointing out the integration of the elements and showing the challenges needed to be faced for the interfaces between the robot modules and the GUI (Graphical User Interface).

This paper presents a new solar arrays deployment mechanism for space applications. It consists of a modular kinematic structure, which is operated by a single cable (1 DoF). Compared to traditional methods, this mechanism has the advantage of being reversible in the movement. Kinematic analysis of the mechanism is carried out in this work, as well as static analysis. They allow to define the main actuation parameters such as cable pull tension and spring stiffness. Moreover, suitable values for the mechanism parameters are computed by means of a dedicated algorithm.

This paper investigates the inverse and forward
kinematic expressions of a three degrees-of-freedom parallel
mechanism with identical limb structures, performing three
independent rotations. The forward kinematic and constraint
expressions are explored in two different spaces, namely, sevendimensional
kinematic space and Euclidean space. The algorithm
applied to obtain the forward kinematic and constraint
equations in seven-dimensional space, by the means of Study
parameters, is a novel approach which is the so-called linear
implicitization algorithm. Moreover, the working and assembly
modes are computed upon writing the kinematic expression in
Euclidean space.