waashk/dblp huggingface dataset:
autonomous single arm oru changeout - strategies, control issues, and implementation. a preliminary strategy for autonomous single arm orbital replacement unit (oru) changeout, the associated compliance and force control issues, and implementation results are described. the changeout operation is separated into subtasks, e.g. bolt-turn, compliant-grasp, and dual-pin-insertion/removal. compliance and force control are done in cartesian space and the selection of appropriate locations for the cartesian control frame is discussed. the dual-pin-insertion/removal subtask requires a decision based strategy in conjunction with compliant control to prevent jamming. actual implementation was done with a puma 560 6 degree of freedom manipulator although the control strategies could be implemented on any manipulator with at least 6 degrees of freedom.
design of a snake-like manipulator. over the past decade, investigations have been made into issues which are specific to the design and control of highly-flexible manipulators - arias which are composed of a large number of small, rigid links. of particular importance to these researchers is the means of joint actuation, since most manipulators in this category are too small to have drive motors placed directly at the joints. this paper also deals with joint actuation, but attacks the problem in a unique fashion. the result is a manipulator in which all of the joints are driven by a single prime mover and whose snake-like motion ensures obstacle avoidance.
constructive recognizability for task-directed robot programming. the primary goal of our research is task-level planning. we approach this goal by utilizing a blend of theory, implementation, and experimentation. we investigate task-level planning for autonomous agents, such as mobile robots, that function in an uncertain environment. these robots typically have very approximate, inaccurate, or minimal models of the environment. for example, although the geometry of its environment is crucial to determining its performance, [footnote:i.e., what the geometry is will have a key role in determining the robot''s actions or behavior.] a mobile robot might only have a partial, or local ``map'''' of the world. similarly, the expected effects of a robot''s actuators critically influence its selection of actions to accomplish a goal, but a robot may have only a very approximate, or local predictive ability with regard to forward-simulation of a control strategy. while mobile robots are typically equipped with sensors in order to gain information about the world, and to compensate for errors in actuation and prediction, these sensors are noisy, and in turn provide inaccurate information. we investigate an approach whereby the robot attempts to acquire the necessary information about the world by planning a series of experiments [footnote: the robot (not the researchers!) performs the experiments, to gain information about the world.] using the robot''s sensors and actuators, and building data-structures based on the robot''s observations of these experiments. a key feature of this approach is that the experiments the robot performs should be driven by the information demands of the task. that is, in performing some task, the robot may enter a state in which making progress towards a goal requires more information about the world (or its own state). in this case, the robot should plan experiments which can disambiguate the situation. when this process is driven by the information demands of the task, we believe it is an important algorithmic technique to effect task-directed sensing. this introductory survey article discusses: 1. a theory of sensor interpretation and task-directed planning using perceptual equivalence classes, intended to be applicable in highly uncertain or unmodelled environments, such as for a mobile robot. 2. algorithmic techniques for modelling geometric constraints on recognizability, and the building of internal representations (such as maps) using these constraints. 3. explicit encoding of the information requirements of a task using a lattice (information hierarchy) of recognizable sets, which allows the robot to perform experiments to recognize a situation or a landmark. 4. the synthesis of robust mobot programs using the geometric constraints, constructive recognizability experiments, and uncertainty models imposed by the task. we discuss how to extend our theory and the geometric theory of planning to overcome challenges of the autonomous mobile robot domain. one of our most important goals is to s
dynamic motion vision. motion vision deals with the analysis of image sequences acquired by a camera moving relative to an environment. the goal is to recover the motion of the camera as well as the structure of the environment. we model the changing structure of the scene perceived in the camera as a dynamical system. the state of this system is the depth, the distance of a scene point from the camera, the measurement is the optical flow, a vector field of image velocities which can be computed from the image brightness arrays acquired by the camera. we use the dynamical systems model in the construction of a kalman filter which optimally estimates the depth of a point in the image incrementally over the sequence of frames. by using one kalman filter per image pixel we are able to recover a dense depth map of the environment, i.e. the scene structure. in every filter iteration we estimate the motion parameters of the camera from the optical flow field using the filter's current depth estimate in a least-squares fashion. the resulting algorithm recovers both the camera motion and the scene structure in an systematic way which could not be accomplished previously. we have implemented this algorithm and tested it on real and synthetic images.
automation in construction. robots are being used in increasing numbers in manufacturing throughout the world. the expanded use of industrial robots in manufacturing and the increased projections of greater numbers in the future has resulted in a greater interest by the construction industry. this paper describes five prototype robots developed by shimizu corporation for applications in construction industry.
intelligent control of an autonomous mobile robot in a hazardous material spill accident - a blackboard structure approach. this paper describes the use of the blackboard architecture for the high level programming and control of autonomous mobile robots in a hazardous material spill emergency situation. the purpose of the robot is to perform some of the tasks which are dangerous for the emergency response personnels. the proposed blackboard system provides a unifying framework for the integration of information from various sensor-based and knowledge-based sub-systems.
off-line programming by cad-systems for welding robots. information theory constitutes more and more an essential element for robots control. it gives a primary role to programming systems which make it possible to take full advantage of the flexibility possibilities of robots. the informatic structure on which these systems rest is more often than not organized around the concept of a programming language specific to robotics [1]. this article sets out the development of a system for automatic production of programs for welding robots control, from cad specification till welding parameters.
nonlinear formation control of unicycle-type mobile robots. we investigate formation control of a group of unicycle-type mobile robots at the dynamics level with a little amount of inter-robot communication. a combination of the virtual structure and path-tracking approaches is used to derive the formation architecture. each individual robot has only position and orientation available for feedback. for each robot, a coordinate transformation is first derived to cancel the velocity quadratic terms. an observer is then designed to globally exponentially/asymptotically estimate the unmeasured velocities. an output feedback controller is designed for each robot. the controller is designed in such a way that the path derivative is left as a free input to synchronize the robots' motion. simulations illustrate the soundness of the proposed controller.
an automated shear stud welding system. stud welding is highly repetitive and stressful on the worker; thus it is a prime candidate for automation. a robotic device, called the ''studmaster'', has been developed at mit which automates stud welding during construction of industrial buildings and can easily be adapted for use on bridge decks. the machine is controlled by a microcomputer, and utilizes a loading and welding mechanism which is actuated by three pneumatic cylinders and one mechanical relay. this mechanism is mounted on a small tracked vehicle which is manually indexed to each weld site by a human operator. expected payback time for an industrially hardened version is estimated to be on the order of 1-2 years.
an effective trajectory generation method for bipedal walking. this paper presents the virtual height inverted pendulum mode (vhipm), which is a simple and effective trajectory generation method for the stable walking of biped robots. vhipm, which is based on the inverted pendulum mode (ipm), can significantly reduce the zero moment point (zmp) error by adjusting the height in the inverted pendulum. we show the relationship between vhipm and other popular trajectory generation methods, and compare the zmp errors in walking when trajectories are generated by various methods including vhipm. we also investigate the sensitivity of the zmp error in vhipm to the step length, walking period and mass distribution of a robot. the simulation results show that vhipm significantly reduces the zmp errors compared to other methods under various circumstances.
the nonholonomic redundancy of second-order nonholonomic mechanical systems. the nonholonomic redundancy of second-order nonholonomic mechanical systems is investigated. it has been verified that the self-motion can be implemented demonstrably by some nonholonomic mechanical systems such as the underactuated redundant manipulators. an exponentially stabilization control method is proposed for a class of underactuated manipulators, of which the number of actuated joints is no less than that of the passive joints. it has been shown that this class of underactuated manipulators are completely controllable when the dynamic coupling of the underactuated manipulators is non-degenerated and the up-boundary of the inputs is large enough. by the proposed control method, we exhibit this class manipulators with zero weight can realize the ''self-motion'' as a full-actuated redundant one. as a typical application, the problem of path tracking with suppressing vibration is investigated for the underactuated redundant manipulators. it is revealed that the vibration of the underactuated redundant manipulator can be converted into an internal resonance that is compatible with the ''self-motion'', while it leads to no vibration at the end-effector of the manipulator. some numerical simulations by a planar four-dof underactuated manipulator with two actuated joints and two passive joints show the effectiveness of the accurate trajectory control method and the value of the self-motion compatible internal resonance.
motion design and learning of autonomous robots based on primitives and heuristic cost-to-go. the task of trajectory design of autonomous vehicles is typically two-fold. first, it needs to take into account the intrinsic dynamics of the vehicle, which are sometimes termed local constraints. second, on a higher level, the designed trajectories must allow the vehicle to achieve some application-specific task. the specification of the task results in the so-called global constraints. both of these two components of trajectory design are generally nontrivial problems, and very often, they are pursued as two parallel areas. when the results drawn from the two areas are applied in conjunction, the synthesis is usually somewhat arbitrary. in this paper, we assume that some optimal control laws are available as a set of motion primitives to address the vehicle dynamics. the trajectories that achieve the task are determined solely through the primitives and do not reference the vehicle dynamics directly. for the higher level, we translate the task into a very special type of cost-to-go function, which is partially specified artificially and partially determined by an admissibility condition imposed by the set of primitives. the optimality feature of the primitives is formally extended to the final trajectory design. we illustrate this result with the example of a mobile robot retrieving an object, which is an interesting problem of its own right. both a direct design approach and a learning approach are presented.
unified controller for both trajectory tracking and point regulation of second-order nonholonomic chained systems. in this article, a unified controller is developed for both trajectory tracking and point regulation of nonholonomic second-order chained systems. the controller design relies on converting the error model of second-order chained systems to the form of perturbed first-order nonholonomic integrator, followed by a dynamic state feedback control law steering the tracking error to origin exponentially. the proposed control law is universal for both trajectory tracking and point regulation, as the reference trajectories can be any one produced by bounded reference inputs. the control design approach is illustrated by application to a planar manipulator with two translational actuated joints and one revolute unactuated joint. simulation results show the effectiveness of the proposed approach.
output-feedback formation tracking control of unicycle-type mobile robots with limited sensing ranges. this paper presents a constructive method to design output-feedback cooperative controllers that force a group of n unicycle-type mobile robots with limited sensing ranges to perform desired formation tracking, and guarantee no collisions between the robots. the robot velocities are not required for control implementation. for each robot an interlaced observer, which is a reduced order observer plus an interlaced term, is designed to estimate the robot unmeasured velocities. the observer design is based on a coordinate transformation that transforms the robot dynamics to a new dynamics, which does not contain velocity quadratic terms. the interlaced term is determined after the formation control design is completed to void difficulties due to observer errors and consideration of collision avoidance. smooth and p times differentiable jump functions are introduced and incorporated into novel potential functions to design a formation tracking control system. despite the robot limited sensing ranges, no switchings are needed to solve the collision avoidance problem. simulations illustrate the results.
a programming and simulation environment for the karlsruhe dextrous hand. in this paper the development of a programming and simulation environment is described, which was especially tailored for programming of multifinger hands. the research has concerned with the programming of the karlsruhe dextrous hand, a non-anthropomorphic three finger gripper with 9 degrees of freedom, which is being developed at our institute. the work presents the results of a task-oriented approach to the object manipulation problem and contains two main parts: a system programming module and an application programming module. this realization supports the interactive generation and evaluation of a hand program using graphical simulation.
automatic visual guidance of a forklift engaging a pallet. this paper presents the development of a prototype vision-guided forklift system for the automatic engagement of pallets. the system is controlled using the visual guidance method of mobile camera-space manipulation, which is capable of achieving a high level of precision in positioning and orienting mobile manipulator robots without relying on camera calibration. the paper contains development of the method, the development of a prototype forklift as well as experimental results in actual pallet engagement tasks. the technology could be added to agv systems enabling them to engage arbitrarily located pallets. it also could be added to standard forklifts as an operator assist capability.
automated modeling of modular robotic configurations. this research presents an automated method to build kinematic and dynamic models for assembling modular components of modular robotic systems. by comparison with other approaches, the proposed method is applicable to any robotic configuration with serial, parallel, or hybrid structures. in addition, it is object oriented so that each modular component is an element with a submodel and the overall model can be assembled from submodels subject to the connection constraints.
reinforcement learning for quasi-passive dynamic walking of an unstable biped robot. a class of biped locomotion called passive dynamic walking (pdw) has been recognized to be efficient in energy consumption and a key to understand human walking. although pdw is sensitive to the initial condition and disturbances, studies of quasi-pdw which incorporates supplemental actuators have been reported to overcome this sensitivity. in this article, we propose a reinforcement learning method designed particularly for quasi-pdw of a biped robot whose possession of knees makes the system unstable. simulations show that the learning is quickly accomplished after 1000 episodes, and the obtained controller is robust against variations in the slope gradient and sudden perturbations.
distributed multi-robot coordination in area exploration. this paper proposes a reliable and efficient multi-robot coordination algorithm to accomplish an area exploration task given that the communication range of each robot is limited. this algorithm is based on a distributed bidding model to coordinate the movement of multiple robots. two measures are developed to accommodate the limited-range communications. first, the distances between robots are considered in the bidding algorithm so that the robots tend to stay close to each other. second, a map synchronization mechanism, based on a novel sequence number-based map representation and an effective robot map update tracking, is proposed to reduce the exchanged data volume when robot subnetworks merge. simulation results show the effectiveness of the use of nearness measure, as well as the map synchronization mechanism. by handling the limited communication range we can make the coordination algorithms more realistic in multi-robot applications.
an integrated approach to the conceptual design and development of an intelligent autonomous mobile robot. this paper proposes a new approach to the design and development of an intelligent mobile robot and discusses the complex functional structure of such systems, providing solutions to some typical design problems. the proposed design approach provides a clearer view of the design problems from a function-oriented interdisciplinary point of view. the approach proves to be a useful tool in allowing the designer to cross the boundaries of technical disciplines and optimise the interdisciplinary system's components, thereby improving the overall system performance. the paper also presents a case study where it takes the design problem from the most abstract level up to the final stage, in which the developed autonomous mobile robot's specifications are verified and validated. the issues addressed in this paper include the design, development, systems integration, and experimental testing of the intelligent mobile robot.
low level controller for a pomdp based on wifi observations. this paper shows the results of a low level controller that has been applied to an autonomous robotic system using a wifi-based partially observable markov decision process (pomdp). these observations provide a clue for global robot localization from the first iteration of the pomdp algorithm. due to the noise channel of wifi measures, it becomes necessary to make observations at a well known location within the environment. therefore, a robust local navigator is needed in order to place the robot in an optimal position for making the observation. the system has been tested with two pioneer 2at robots in the premises of the department of electronics at the university of alcala.
a sensor for dynamic tactile information with applications in human-robot interaction and object exploration. we present a novel tactile sensor, which is applied for dextrous grasping with a simple robot gripper. the hardware novelty consists of an array of capacitive sensors, which couple to the object by means of little brushes of fibers. these sensor elements are very sensitive (with a threshold of about 5 mn) but robust enough not to be damaged during grasping. they yield two types of dynamical tactile information corresponding roughly to two types of tactile sensor in the human skin. the complete sensor consists of a foil-based static force sensor, which yields the total force and the center of the two-dimensional force distribution and is surrounded by an array of the dynamical sensor elements. one such sensor has been mounted on each of the two gripper jaws of our humanoid robot and equipped with the necessary read-out electronics and a can bus interface. we describe applications to guiding a robot arm on a desired trajectory with negligible force, reflective grip improvement, and tactile exploration of objects to create a shape representation and find stable grips, which are applied autonomously on the basis of visual recognition.
a 3-level autonomous mobile robot navigation system designed by using reasoning/search approaches. this paper describes how soft computing methodologies such as fuzzy logic, genetic algorithms and the dempster-shafer theory of evidence can be applied in a mobile robot navigation system. the navigation system that is considered has three navigation subsystems. the lower-level subsystem deals with the control of linear and angular volocities using a multivariable pi controller described with a full matrix. the position control of the mobile robot is at a medium level and is nonlinear. the nonlinear control design is implemented by a backstepping algorithm whose parameters are adjusted by a genetic algorithm. we propose a new extension of the controller mentioned, in order to rapidly decrease the control torques needed to achieve the desired position and orientation of the mobile robot. the high-level subsystem uses fuzzy logic and the dempster-shafer evidence theory to design a fusion of sensor data, map building, and path planning tasks. the fuzzy/evidence navigation based on the building of a local map, represented as an occupancy grid, with the time update is proven to be suitable for real-time applications. the path planning algorithm is based on a modified potential field method. in this algorithm, the fuzzy rules for selecting the relevant obstacles for robot motion are introduced. also, suitable steps are taken to pull the robot out of the local minima. particular attention is paid to detection of the robot's trapped state and its avoidance. one of the main issues in this paper is to reduce the complexity of planning algorithms and minimize the cost of the search. the performance of the proposed system is investigated using a dynamic model of a mobile robot. simulation results show a good quality of position tracking capabilities and obstacle avoidance behavior of the mobile robot.