1 A Proposed Hardware and Software Architecture for a Robotic System Gutemberg S. Santiago and Adelardo A. D. Medeiros Abstract—To manage the procedure of capturing, processing, database maps, computational models response, status situa- and delivering all sensory information acquired by a complex tions achieved, and it needs to delivery some action to mobile robotic system, a robot architecture is needed. This class of robots devices of the robotic system. The software architecture man- deals with concurrent embedded real-time performance and intelligent algorithms at same time. The development of a generic ages the relationship among these decision algorithms. The robotic architecture to complex robotics systems has mainly two hardware architecture manages the sensors capture process challengers: the complex level of the robotic systems; and the and their configuration and the delivery process of decision hardware diversity that robots are built. To deal with these information to the actuators movement. problems a distributed hardware and software architecture for Due to hard sensory information processing, a complex robotic systems was developed using communication standards. This architecture aims to manage different robots and provide robotic system needs a distributed computational processing. a distributed communication system which allows the robots These systems may have many embedded computers to pro- communicate among themselves and with a control base station. cess the information. The subsystems that need hard real- This proposed architecture is based on CAN Network and ROS time processing use a separated embedded computer, since Framework using Orocos RTT Framework, and it is being they consume all the CPU power processing and need a implemented on a mobile robot at initial stage of building. real-time operational system. Other subsystems hold only a Index Terms—Robot Architecture, Complex Robotic Systems, system monitoring tasks and use a single computer with no Embedded Systems, CAN Network, ROS Framework, Orocos restrictions. RTT Framework. Robotic systems generally communicates with a base station or with other robots. A robotic architecture has to handle with I. INTRODUCTION this distributed robotic system configuration. A base station can define the tasks of the robot, environment restrictions, ROBOTIC systems are mechatronic devices capable of control and monitoring. A robot team is a robotic system R performing autonomous tasks. These systems combines configuration which robots communicate with each other and mechanics, electronics, computing and control engineering joint efforts to perform a task. with a certain degree of autonomy, based on some heuristic The general control system for a robotic system with a or artificial intelligence, to make possible the generation of a certain degree of autonomy and complexity is required to reliable and versatile robotic system. meet some behavior specifications and design requirements: Complex robotic systems are a class of robots which deals reactivity to the environment; intelligent behavior; resolving of with concurrent embedded real-time performance and intelli- multiple goals; global reasoning; reliability; and adaptability gent algorithms at the same time. The complexity level on [1] [2]. the development of these robots is based on the hard real- The development of a new architecture has mainly two time performance needed, on the slow intelligent algorithms challenges: the complex level of the robotic systems and the processing, and on the data exchange among software and hardware diversity that robots are built. hadware processes at robot. The complexity level of the robot development has grown. The degree of autonomy of these systems is directly related The architecture needs to be capable to deal with many to the amount of acquired sensor information. The robotic characteristics compatible to the more powerful computer systems take decisions based on sensory information. The (nowadays embedded computers), the more compact electronic more sensory information is processed, the more the robot circuits and new kinds of processed data sensors. Sensor like is capable of performing tasks. If this sensory information is lasers and cameras produce rich information after the data obtained from different kinds of sensors and have a certain processing. degree of redundancy, all these information can be fused to Considering the robot architecture point of view, robots can obtain a more accurate system performance. be classified as having a basic mechatronic system or having To manage the procedure of capturing, processing, and a complex mechatronic system [3] [4]. A basic mechatronic delivering all sensory information acquired, hardware and system is generally characterized for one arm robotic system software architecture are used. The decision algorithms pro- or a basic mobile robot. Generally these robots have no time cessing needs to be fed from sensory information, robot restrictions. A complex mechatronic system is usually char- acterized for a mix of basic mechatronics systems. Generally The authors are with the Department of Computing and Automation Engineering, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil these robots have strong time restrictions (Figures 1 and 2). (e-mail: [email protected]; [email protected]). Some robotic systems present special architecture capabil- 2 hardware and software architecture for autonomous complex robotic systems. II. ARCHITECTURE CONCEPTS The main objective is to develop a distributed hardware and software architecture for robotic systems. This architec- ture aims to manage any kind of robot: underwater, surface, terrestrial, aerial and spatial. This architecture will provide a distributed communication system which will permit the robots to communicate among themselves and with a control base station. The specific objectives are: • to ensure a set of characteristics that the architecture of Fig. 1. Autonomous Complex Fig. 2. Autonomous Complex all the built robots will provide. For example, the real- Robotic System: ASIMO Robot from Robotic System: Justin Robot from n Honda (Picture from website [5]). DLR (Picture from website [6]). time communication bandwidth guarantee for a number of dispositives plugged into the robot; • to manage the interface between the real-time require- ities. An example is a fast reaction that a visual system is ments of the manipulation tasks of the robot and the non- capable: to shoot a cellphone and hold it back again. This realtime computational intelligent process of the decision is demonstration of skillful manipulation using a high-speed algorithms; robot system (Figure 3) [7]. • to standardize the communication interfaces among the robot dispositives and to standardize the communication interfaces among the main parts of the robot. • to develop an architecture capable of integrating and validating new technologies, such as different kinds of actuators and sensors. The methodology used to develop this new architecture was divided into two parts: the hardware part including the sensors, Fig. 3. Regrasping task (from left to right). Ishikawa Komuro Lab’s high-speed robot hand performing impressive acts of dexterity and skillful actuators and real-time network management; and the software manipulation. The system consists of visual and tactile sensors at a rate of part including the distributed manager base on the hybrid 1kHz and a high-speed hand-arm manipulator. Pictures from [7]. Ishikawa deliberative-reactive paradigm. Komuro Laboratory, Department of Creative Informatics, University of Tokyo. The hardware development methodology is to concentrate different types of sensors and actuators in a real-time industrial The lack of standards in the robots development makes network. The sensors and actuators are plugged into the each building different from each other. Robots have different industrial network through an interface board based on a physical characteristics and different hardware architectures. micro-controller. All dispositives will provide self-information In addition redundant infrastructure for robotic platforms is based on a sensor intelligent standard, such that when a developed with no interoperability among these platforms. No dispositive is plugged in the network, it negotiates with the framework is developed to capture new technologies. bus administrator manager and became available if previously Currently there is a relevant discurssion among the scientists approved. The external communication will be provided by of robots architecture to develop a hardware and software an Ethernet network and will permit the communication with robot standardization, once each robot is built with its own different types of robots. The vision system will be based on hardware and software. With the financial support of the specific image hardware processing. European Commission and the Robot Standards and Reference Architectures Consortium, the RAS Standing Committee on Standardization Activities has established a study group in III. ARCHITECTURE COMPONENTS 2007 and has organized a series of open workshops and The hardware elements used to compose the proposed expert meetings to address the questions of measurability, architecture are the IEEE 1451 protocol for smart sensors comparability, interoperability, and reusability of architectural which interfaces the robot sensors and actuators to the CAN concepts and components in robotics [8]. network; the Control Area Network