Path Coordination Planning and Control in Robotic Material Handling and Processing

This chapter presents a unified approach to coordination planning and control for robotic position and orientation trajectories in Cartesian space and its applications in robotic material handling and processing. The unified treatment of the end-effector positions and orientations is based on the robot pose ruled surface concept and used in trajectory interpolations. The focus of this chapter is on the determination and control of the instantaneous change laws of position and orientation, i.e., the generation and control of trajectories with good kinematics and dynamics performances along such trajectories. The coordination planning and control is implemented through controlling the motion laws of two end points of the orientation vector and calculating the coordinates of instantaneous corresponding points. The simulation and experiment in robotic surface profiling/finishing processes are presented to verify the feasibility of the proposed approach and demonstrate the capabilities of planning and control models. Keywords: Robot pose ruled surface, Unified approach, Trajectory planning and control, Off-line programming, Robotics polishin

Robot Acting on Moving Bodies (RAMBO): Interaction with tumbling objects

Interaction with tumbling objects will become more common as human activities in space expand. Attempting to interact with a large complex object translating and rotating in space, a human operator using only his visual and mental capacities may not be able to estimate the object motion, plan actions or control those actions. A robot system (RAMBO) equipped with a camera, which, given a sequence of simple tasks, can perform these tasks on a tumbling object, is being developed. RAMBO is given a complete geometric model of the object. A low level vision module extracts and groups characteristic features in images of the object. The positions of the object are determined in a sequence of images, and a motion estimate of the object is obtained. This motion estimate is used to plan trajectories of the robot tool to relative locations rearby the object sufficient for achieving the tasks. More specifically, low level vision uses parallel algorithms for image enhancement by symmetric nearest neighbor filtering, edge detection by local gradient operators, and corner extraction by sector filtering. The object pose estimation is a Hough transform method accumulating position hypotheses obtained by matching triples of image features (corners) to triples of model features. To maximize computing speed, the estimate of the position in space of a triple of features is obtained by decomposing its perspective view into a product of rotations and a scaled orthographic projection. This allows use of 2-D lookup tables at each stage of the decomposition. The position hypotheses for each possible match of model feature triples and image feature triples are calculated in parallel. Trajectory planning combines heuristic and dynamic programming techniques. Then trajectories are created using dynamic interpolations between initial and goal trajectories. All the parallel algorithms run on a Connection Machine CM-2 with 16K processors

Optimal Sampling-Based Motion Planning under Differential Constraints: the Driftless Case

Motion planning under differential constraints is a classic problem in robotics. To date, the state of the art is represented by sampling-based techniques, with the Rapidly-exploring Random Tree algorithm as a leading example. Yet, the problem is still open in many aspects, including guarantees on the quality of the obtained solution. In this paper we provide a thorough theoretical framework to assess optimality guarantees of sampling-based algorithms for planning under differential constraints. We exploit this framework to design and analyze two novel sampling-based algorithms that are guaranteed to converge, as the number of samples increases, to an optimal solution (namely, the Differential Probabilistic RoadMap algorithm and the Differential Fast Marching Tree algorithm). Our focus is on driftless control-affine dynamical models, which accurately model a large class of robotic systems. In this paper we use the notion of convergence in probability (as opposed to convergence almost surely): the extra mathematical flexibility of this approach yields convergence rate bounds - a first in the field of optimal sampling-based motion planning under differential constraints. Numerical experiments corroborating our theoretical results are presented and discussed

Implementation of an anthropomorphic robot cell via Web Services and free path interpolation implementating De Casteljau's algorithm

Industrial automation technology evolves rapidly, and automated manufacturing systems need to find a way to improve the implementation and installation of new devices in the system. Adaptable and flexible systems reduce the time and cost of integration. One of the aspects to consider when building an adaptable and interoperable systems is the management of data flow between devices in the system. New technologies like web services have been implemented in manufacturing systems under a Service-Oriented Architecture (SOA). Currently, robots are capable of performing simple paths composed of Point-to Point (PTP), linear and circular motions, which are adequate for most applications. However, some applications require the use of complex smooth paths to complete their operations. Robots require a simple and robust method to model complex paths within the industrial controller. There are two main components to this thesis. One of the objectives of this thesis is to propose an approach to implement a robotic cell into a production line by using web services. This approach exposes the functionalities of the robot as services to the system, where those services can be requested via RESTful web services. The other component of the thesis presents a way for a robot to model and perform free shape paths through the evaluation of Bezier curves and the implementation of the De Casteljau algorithm into the robot controller. The proposed approach was successfully deployed and tested on a production scenario. The testbed used was the FASTory production line, in the Factory Automation Systems and Technologies Laboratory (FAST-Lab) in Tampere University. The results of the tests show that the implementation of the approach dotes the system with flexibility and configurability and simplicity of installation

Physical Interaction and Control of Robotic Systems Using Hardware-in-the-Loop Simulation

Robotic systems used in industries and other complex applications need huge investment, and testing of them under robust conditions are highly challenging. Controlling and testing of such systems can be done with ease with the support of hardware-in-the-loop (HIL) simulation technique and it saves lot of time and resources. The chapter deals on the various interaction methods of robotic systems with physical environments using tactile, force, and vision sensors. It also discusses about the usage of hardware-in-the-loop technique for testing of grasp and task control algorithms in the model of robotic systems. The chapter also elaborates on usage of hardware and software platforms for implementing the control algorithms for performing physical interaction. Finally, the chapter summarizes with the case study of HIL implementation of the control algorithms in Texas Instruments (TI) C2000 microcontroller, interacting with model of Kuka’s youBot Mobile Manipulator. The mathematical model is developed using MATLAB software and the virtual animation setup of the robot is developed using the Virtual Robot Experimentation Platform (V-REP) robot simulator. By actuating the Kuka’s youBot mobile manipulator in the V-REP tool, it is observed to produce a tracking accuracy of 92% for physical interaction and object handling tasks

Real-time interpolation of streaming data

One of the key elements of real-time $C^1$-continuous cubic spline interpolation of streaming data is an estimator of the first derivative of the interpolated function that is more accurate than the ones based on finite difference schemas.Two such greedy look-ahead heuristic estimators (denoted as MinBE and MinAJ2) based on Calculus of Variations are formally defined (in closed form) together with the corresponding cubic splines they generate, and then comparatively evaluated in a series of numerical experiments involving different types of performance measures. The results presented show that the cubic Hermite splines generated by heuristic MinAJ2 significantly outperformed these based on finite difference schemas in terms of all tested performance measures (including convergence).The proposed approach is quite general. It can be directly applied to streams of univariate functional data like time-series. Multidimensional curves defined parametrically, after splitting, can be handled as well. The streaming character of the algorithm means that it can also be useful in processing data sets that are too large to fit in memory (e.g., edge computing devices, embedded time-series databases)