5 research outputs found
A 2-Dimensional ACO-Based Path Planner for Off-Line Robot Path Planning
Wireless sensor networks are usually deployed in scenarios that are too hostile for human personnel to perform maintenance tasks. Wireless sensor nodes usually exchange information in a multi-hop manner. Connectivity is crucial to the performance of a wireless sensor network. In case a network is partitioned due to node failures, it is possible to re-connect the fragments by setting up bridges using mobile platforms. Given the landscape of a terrain, the mobile platforms should be able reach the target position using a desirable path. In this paper, an off-line robot path planner is proposed to find desirable paths between arbitrary points in a given terrain. The proposed path planner is based on ACO algorithms. Unlike ordinary ACO algorithms, the proposed path planner provides its artificial ants with extra flexibility in making routing decisions. Simulation results show that such enhancement can greatly improve the qualities of the paths obtained. Performances of the proposed path planner can be further optimized by fine-tuning its parameters.Department of Electronic and Information EngineeringRefereed conference pape
Enhanced online programming for industrial robots
The use of robots and automation levels in the industrial sector is expected to grow, and is driven by the on-going need for lower costs and enhanced productivity. The manufacturing industry continues to seek ways of realizing enhanced production, and the programming of articulated production robots has been identified as a major area for improvement. However, realizing this automation level increase requires capable programming and control technologies. Many industries employ offline-programming which operates within a manually controlled and specific work environment. This is especially true within the high-volume automotive industry, particularly in high-speed assembly and component handling. For small-batch manufacturing and small to medium-sized enterprises, online programming continues to play an important role, but the complexity of programming remains a major obstacle for automation using industrial robots. Scenarios that rely on manual data input based on real world obstructions require that entire production systems cease for significant time periods while data is being manipulated, leading to financial losses. The application of simulation tools generate discrete portions of the total robot trajectories, while requiring manual inputs to link paths associated with different activities. Human input is also required to correct inaccuracies and errors resulting from unknowns and falsehoods in the environment. This study developed a new supported online robot programming approach, which is implemented as a robot control program. By applying online and offline programming in addition to appropriate manual robot control techniques, disadvantages such as manual pre-processing times and production downtimes have been either reduced or completely eliminated. The industrial requirements were evaluated considering modern manufacturing aspects. A cell-based Voronoi generation algorithm within a probabilistic world model has been introduced, together with a trajectory planner and an appropriate human machine interface. The robot programs so achieved are comparable to manually programmed robot programs and the results for a Mitsubishi RV-2AJ five-axis industrial robot are presented. Automated workspace analysis techniques and trajectory smoothing are used to accomplish this. The new robot control program considers the working production environment as a single and complete workspace. Non-productive time is required, but unlike previously reported approaches, this is achieved automatically and in a timely manner. As such, the actual cell-learning time is minimal
Optimization and application of a flexible dual arm robot based automation system for sample preparation and measurement
This dissertation describes the optimization of the implementation of the Yaskawa SDA10F dual-arm robot to carry out routine sample preparation tasks in a life science laboratory such that standard lab equipment can be used and the robot can replace humans in sample preparation process. The existing robot control software is changed to carry out various tasks consecutively without interruption. Robot environment and motions were optimized allowing system expansion, multiple batches of samples are made at a time, increasing throughput. The system was validated with the help of two applications
Ătude dâun systĂšme interactif sĂ©curitaire dĂ©diĂ© Ă lâinteraction humain-robot appliquĂ© Ă des mĂ©canismes parallĂšles entraĂźnĂ©s par des cĂąbles
Depuis l'introduction des premiers robots interactifs en industrie, qui Ă©taient Ă la base des systĂšmes collaboratifs supposĂ©s assister les humains dans les tĂąches pĂ©nibles et Ă©prouvantes physiquement, le domaine de lâinteraction humain-robot a fait des progrĂšs considĂ©rables. Actuellement, les robots et les humains peuvent coexister conjointement dans un espace hybride afin de partager des tĂąches de production ou de partager le temps dans lâexĂ©cution dâune activitĂ©. Cependant, les nouveaux besoins industriels doivent conduire Ă des recherches pour adapter les chaĂźnes de production et les rendre plus flexible et rĂ©active Ă la modification des caractĂ©ristiques des produits. Lâune des solutions consiste Ă adapter le manipulateur industriel prĂ©sent dans les lignes de production Ă des fins dâinteraction et de collaboration. Toutefois, la prĂ©sence de lâhumain dans lâespace de travail dâun manipulateur (cellule de travail hybride) reprĂ©sente un rĂ©el dĂ©fi dans le domaine de lâinteraction humain-robot puisque cela consiste Ă lâintĂ©gration dâune multitude de variĂ©tĂ©s de capteurs dits intelligents, surtout dans le cas de lâutilisation dâun mĂ©canisme parallĂšle entraĂźnĂ© par des cĂąbles. Pour cette raison, plusieurs problĂ©matiques ont Ă©tĂ© soulevĂ©es, pour lesquelles peu ou pas de recherches sont rĂ©alisĂ©es : cette nouvelle technologie est introduite sans entraĂźnement de lâopĂ©rateur, lâĂ©valuation de la sĂ©curitĂ© a Ă©tĂ© trĂšs peu explorĂ©e lors de lâinteraction et la performance de son utilisation demeure peu Ă©valuĂ©e dans un contexte de rĂ©duction des troubles musculosquelettiques (TMS). Le projet de recherche vise lâĂ©tude et la conception dâun systĂšme interactif permettant dâamĂ©liorer la sĂ©curitĂ© et lâintuitivitĂ© des personnes qui interagissent avec des mĂ©canismes parallĂšles entraĂźnĂ©s par des cĂąbles. Deux modes dâinteraction sont Ă©tudiĂ©s dans le systĂšme interactif, Ă savoir le partage des activitĂ©s et lâinteraction physique. En premier lieu, une mĂ©thode de gĂ©nĂ©ration de trajectoires avec Ă©vitement de collisions appliquĂ©e pour le mode de partage des activitĂ©s est proposĂ©e. Lâeffecteur du manipulateur suit un chemin dans lâespace opĂ©rationnel Ă travers des points de passage. Ces derniers sont gĂ©nĂ©rĂ©s par un rĂ©seau de neurones rĂ©tropropagation (Back-propagation), et sont reliĂ©s par un polynĂŽme quintique (de degrĂ© cinq). En outre, la gĂ©omĂ©trie dĂ©formable de lâobstacle et lâenvironnement dynamique sont pris en compte dans la mĂ©thode. En second lieu, une approche est abordĂ©e pour dĂ©terminer la distance minimale entre les cĂąbles et identifier ceux qui sont en interfĂ©rence. Le calcul de distance est exĂ©cutĂ© en temps rĂ©el Ă travers un algorithme. En outre, les contraintes physiques des cĂąbles ont Ă©tĂ© prises en compte dans la modĂ©lisation mathĂ©matique et formulĂ©es en un problĂšme dâoptimisation non linĂ©aire. Ce dernier est rĂ©solu en utilisant lâapproche de Karush-Kuhn-Tucker (KKT). Cette mĂ©thode de calcul de distance est intĂ©grĂ©e Ă une loi de commande interactive permettant de gĂ©rer les cĂąbles en interfĂ©rence pendant lâinteraction physique avec le mĂ©canisme. Une force est calculĂ©e et introduite dans la boucle de la commande afin dâĂ©viter le croisement et le relĂąchement des cĂąbles en interfĂ©rence. Par ce fait, la tĂąche est exĂ©cutĂ©e jusquâaux limites des possibilitĂ©s gĂ©omĂ©triques et cinĂ©matiques du mĂ©canisme. Par ailleurs, cette stratĂ©gie est basĂ©e sur une commande en admittance pour permettre lâinteraction physiquement avec un mĂ©canisme parallĂšle entrainĂ© par des cĂąbles. Un algorithme permettant de sĂ©lectionner entre ces deux modes est proposĂ©. Cette approche inclut un vĂȘtement intelligent pour le changement de mode de maniĂšre intuitive simple et rapide. Lâalgorithme est exĂ©cutĂ© en temps rĂ©el et basĂ© sur une identification de gestes utilisant un polynĂŽme dâinterpolation trigonomĂ©trique. Les signaux analysĂ©s proviennent dâune semelle instrumentĂ©e qui est situĂ©e au niveau du pied. Enfin, les diffĂ©rents algorithmes et stratĂ©gies sont validĂ©s en simulations et Ă travers des expĂ©rimentations sur un mĂ©canisme parallĂšle entrainĂ© par sept cĂąbles. Ce projet de thĂšse apporte plusieurs contributions dans le domaine de lâinteraction humain-robot notamment la capacitĂ© dâadaptation du systĂšme interactif pour des tĂąches industrielles.
Since the introduction of the first interactive robots in industry, which was the collaborative robots (labelled as COBOT), the field of human robot interaction has made considerable progress. In its early version, those robots were used to increase muscle strength of the operator for moving heavy loads. Recently, robots and humans can share the same workspace, production activities or working time. However, new needs in industry require more flexibility and reactivity supporting fast changes in product characteristics. One solution consists in the adaptation of an industrial robot, that is already installed in the production line, for interaction and collaboration purposes such as kinetic learning assembly task, and adaptive third hand. However, the presence of the human in the manipulatorsâ workspace (hybrid work cell) represents a real challenge in the field of human-robot interaction. It consists in the integration of an intelligent sensor varieties, especially when the cables driven parallel mechanisms (CDPM) are used for an interaction task. For these reasons, several issues have been raised, for which few or no research has been done yet. This new technology is introduced without any operators training and the safety assessment has been very little explored during the interaction. Moreover, the performance of its use remains poorly evaluated in a context of reduction of musculoskeletal disorders (MSDs). The research project aims to study and design an interactive system in order to improve the safety and the intuitivity when the humans interact with cables driven parallel mechanisms. Two modes of cooperation are studied in the interactive system, namely the sharing of activities and the physical interaction. First, a trajectory generating method for an industrial manipulator in a shared workspace is proposed. A neural network using a supervised learning is applied to create the waypoints required for dynamic obstacles avoidance. These points are linked with a quintic polynomial function for smooth motion which is optimized using least-square to compute an optimal trajectory. Moreover, the evaluation of human motion forms has been taken into consideration in the proposed strategy. Second, a mathematical approach is presented to determine the minimum distance between cables and to identify which ones are interfering. To execute this approach in real time, an algorithm is also presented for calculating this distance. Furthermore, the physical constraints of the cables have been considered in mathematical modeling and formulated into a nonlinear optimization problem. The latter is solved using the Karush-Kuhn-Tucker (KKT) approach. This method of distance calculation is integrated with a new interactive control that eliminates the computation of the effect of a folding interfered cable. A control strategy is proposed, which allows to manage the cables in interference while the operator physically interacts with the mechanism. A repulsive force is generated and introduced to the controller to avoid the cables crossing and folding. Therefore, the task is executed within the limits of the kinematic possibilities. Moreover, this strategy is based on an admittance control for physically interacting with a CDPM. In order to allow a change of intuitive interaction mode, an algorithm for selecting between these two modes is proposed. This approach includes an instrumented insole placed into a shoe for intuitive mode change quick and easy. The algorithm is executed in real time and based on a gesture identification using a trigonometric interpolation polynomial. Finally, theses different strategies and algorithms are validated in simulations and through experiments on a parallel mechanism driven by seven cables. This thesis project brings several contributions in the field of human-robot interaction including the ability of the interactive system to adapt for industrial tasks