Orccad, a framework for safe robot control design and implementation

International audienceRobotic systems are typical examples of hybrid systems where continuous time aspects, related to control laws, must be carefully merged with discrete-time aspects related to control switches and exception handling. These two aspects interact in real-time to ensure an efficient nominal behaviour of the system together with safe and graceful degradation otherwise. In a mixed synchronous/asynchronous approach, ranging from user's requirements to run-time code, Orccad provides formalised real-time control structures, the coordination of which is specified using the \esterel\ synchronous language. CAD tools have been developed and integrated to help the users along the steps of the design, verification, implementation and exploitation processes

Tools for Real-Time Control Systems Co-Design : A Survey

This report presents a survey of current simulation tools in the area of integrated control and real-time systems design. Each tool is presented with a quick overview followed by a more detailed section describing comparative aspects of the tool. These aspects describe the context and purpose of the tool (scenarios, development stages, activities, and qualities/constraints being addressed) and the actual tool technology (tool architecture, inputs, outputs, modeling content, extensibility and availability). The tools presented in the survey are the following; Jitterbug and TrueTime from the Department of Automatic Control at Lund University, Sweden, AIDA and XILO from the Department of Machine Design at the Royal Institute of Technology, Sweden, Ptolemy II from the Department of Electrical Engineering and Computer Sciences at Berkeley, California, RTSIM from the RETIS Laboratory, Pisa, Italy, and Syndex and Orccad from INRIA, France. The survey also briefly describes some existing commercial tools related to the area of real-time control systems

D04.05 - Feasibility mock-ups of feedback schedulers

Control and computation co-design deals with the interaction between feedback control laws design and their implementation on a real execution resource. Control design is often carried out in the framework of continuous time, or under the assumption of ideal sampling with equidistant intervals and known delays. Implementation on a real-time execution platform introduces many timing uncertainties and distortions to the ideal timing scheme, e.g. due to variable computation durations, complex preemption patterns between concurrent activities, uncertain network induced communication delays or occasional data loss. Analyzing, prototyping, simulating and guaranteeing the safety of complex control systems are very challenging topics. Models are needed for the mechatronic continuous system, for the discrete controllers and diagnosers, and for network behavior. Real-time properties (task response times) and the network Quality of Service (QoS) influence the controlled system properties (Quality of Control, QoC). To reach effective and safe systems it is not enough to provide theoretic control laws and leave programmers and real-time systems engineers just do their best to implement the controllers. This report first describes, through the detailed design of a quadrotor drone controller, the main features of {\sc Orccad}, an integrated development environment aimed to bridge the gap between advanced control design and real-time implementation. Besides control design and implementation, a real-time (hardware-in-the-loop) simulation has been designed to assess the control design with a simulated target rather than with the real plant. Using this HIL structure, several experiments using flexible real-time control features are reported, namely Kalman filters subject to data loss, control under (m,k)-firm constraints, control with varying sampling rates and feedback scheduling using the MPC approach

Automatic generation of discrete handlers of real-time continuous control tasks

International audienceWe present a novel technique for designing discrete, logical control loops, on top of continuous control tasks, ensuring logical safety properties of the tasks sequencings and mode changes. We define this new handler on top of the real-time executives built with the ORCCAD design environment for control systems, which is applied, e.g. to robotics and real-time networked control. It features structures of control tasks, each equipped with a local automaton, used for the reactive, event-based management of its activity and modes. The additional discrete handler manages the interactions between tasks, concerning, e.g., mutual exclusions, forbidden or imposed sequences. We use a new reactive programming language, with constructs for finite-state machines and data-flow nodes, and a mechanism of behavioral contracts, which involves discrete controller synthesis. The result is a discrete control loop, on top of the continuous control loops, all integrated in a coherent real-time architecture. Our approach is illustrated and validated experimentally with the case study of a robot arm

Robotics Middleware: A Comprehensive Literature Survey and Attribute-Based Bibliography

Autonomous robots are complex systems that require the interaction between numerous heterogeneous components (software and hardware). Because of the increase in complexity of robotic applications and the diverse range of hardware, robotic middleware is designed to manage the complexity and heterogeneity of the hardware and applications, promote the integration of new technologies, simplify software design, hide the complexity of low-level communication and the sensor heterogeneity of the sensors, improve software quality, reuse robotic software infrastructure across multiple research efforts, and to reduce production costs. This paper presents a literature survey and attribute-based bibliography of the current state of the art in robotic middleware design. The main aim of the survey is to assist robotic middleware researchers in evaluating the strengths and weaknesses of current approaches and their appropriateness for their applications. Furthermore, we provide a comprehensive set of appropriate bibliographic references that are classified based on middleware attributes.http://dx.doi.org/10.1155/2012/95901

Functional Rehabilitation: Coordination of Artificial and Natural Controllers

International audienceWalking and standing abilities, though important for quality of life and participation in social and economic activities, can be adversely affected by central nervous system (CNS) disorders such as spinal cord injury, stroke or traumatic brain injury. One characteristic of motor deficiencies which affect lower extremities is their impact on both static and dynamic postural equilibrium. Depending on the impairment level, functional rehabilitation techniques may be needed for a patient to stand up and walk (Popovic and Sinkjær, 2003). Functional electrical stimulation (FES) can induce contraction of skeletal muscles by applying electrical stimuli to sensory-motor system via electrodes which can be placed on the skin (Kralj et al., 1983), or implanted (Guiraud et al., 2006). FES applications applied to lower limbs include foot drop correction, single joint control, cycling, standing up, walking... (Zhang and Zhu, 2007)..

A Domain-Specific Language for Multitask Systems, Applying Discrete Controller Synthesis

International audienceWe propose a simple programming language, called Nemo, specific to the domain of multitask real-time control systems, such as in robotic, automotive, or avionics systems. It can be used to specify a set of resources with usage constraints, a set of tasks that consume them according to various modes, and applications sequencing the tasks. We automatically obtain an application-specific task handler that correctly manages the constraints (if there exists one), through a compilation-like process including a phase of discrete controller synthesis. This way, this formal technique contributes to the safety of the designed systems, while being encapsulated in a tool that makes it usable by application experts. Our approach is based on the synchronous modelling techniques, languages, and tools

Specifying and verifying active vision-based robotic systems with the Signal environment

International audienceActive vision-based robot design involves a variety of techniques and formalisms, from kinematics to control theory, signal processing and computer science. The programming of such systems therefore requires environments with many different functionalities, in a very integrated fashion in order to ensure consistency of the different parts. In significant applications, the correct specification of the global controller is not simple to achieve, as it mixes different levels of behavior, and must respect properties. In this paper we want to advocate the use of a strongly integrated environment able to deal with the design of such systems from the specification of both continuous and discrete parts down to the verification of dynamic behavior. The synchronous language signal is used here as a candidate integrated environment for the design of active vision systems. Our experiments show that signal, while not being an environment devoted to for robotics (but more generally dedicated to control theory and signal processing), presents functionalities and a degree of integration that are relevant to the safe design of active vision-based robotics system

Model-driven engineering approach to design and implementation of robot control system

In this paper we apply a model-driven engineering approach to designing domain-specific solutions for robot control system development. We present a case study of the complete process, including identification of the domain meta-model, graphical notation definition and source code generation for subsumption architecture -- a well-known example of robot control architecture. Our goal is to show that both the definition of the robot-control architecture and its supporting tools fits well into the typical workflow of model-driven engineering development.Comment: Presented at DSLRob 2011 (arXiv:cs/1212.3308