José Baca

A heterogeneous modular robotic design for fast response to a diversity of tasks

This paper describes a heterogeneous modular robot system design which attempts to give a quick solution to a diversity of tasks. The approach is based on the use of an inventory of three types of modules i.e., power and control module, joint module and specialized module. Each module type aims to balance versatility and functionality. Their design permits rapid and cost effective design and fabrication. They are interchangeable in different ways to form different robot or system configurations. Depending on the task, the operator decides what type of robot can provide the best performance within the mission. A spherical joint module is described and used to build different robots, hence, forward and inverse kinematics models are obtained. Finally, from the modules described in this work, several robot configurations such as robotic arms, leg-based robots and wheel-based robots are assembled to demonstrate the execution of manipulation and locomotion tasks.

Modular robot systems towards the execution of cooperative tasks in large facilities

Large facilities present with wide range of tasks and modular robots present as a flexible robot solution. Some of the tasks to be performed in large facilities can vary from, achieving locomotion with different modular robot (M-Robot) configurations or the execution of cooperative tasks such as moving objects or manipulating objects with multiple modular robot configurations (M-Robot colony) and existing robot deployments. The coordination mechanisms enable the M-Robots to perform cooperative tasks as efficiently as specialised or standard robots. The approach is based on the combination of two communication types i.e., Inter Robot and Intra Robot communications. Through this communication architecture, tight and loose cooperation strategies are implemented to synchronise modules within an M-Robot configuration and to coordinate M-Robots belonging to the colony. These cooperation strategies are based on a closed-loop discrete time method, a remote clock reading method and a negotiation protocol. The coordination mechanisms and cooperation strategies are implemented into a real modular robotic system, SMART. The need for using such a mechanism in hazardous section of large scientific facilities is presented along with constraints and tasks. Locomotion execution of the mobile M-Robots colony in a bar-pushing task is used as an example for cooperative task execution of the coordination mechanisms and results are presented. We present the results of cooperative task execution using heterogeneous modular robotic system (MRS).It is performed using tight and loosely coupled inter and intra robot configurations.The approach is based on the use of an inventory of three types of basic modules of the modular robot system.The heterogeneity in MRS is an advantageous property for the diverse tasks in large facilities.

A modular robot system design and control motion modes for locomotion and manipulation tasks

This paper describes a modular robot system design SMART, based on three types of modules for urban search tasks. The system attempts to give a quick solution to natural and man-made disaster emergencies. It allows for rapid and cost-effective design and fabrication. The approach is based on the use of an inventory of three types of modules i.e., power and control module, joint module, and specialized module. They are interchangeable in different ways to form different robot configurations for a variety of tasks. Forward and inverse kinematics from assembled robot configurations are analyzed. Description of control motion modes for human-modular robot system interaction is presented.

Modelling of Modular Robot Configurations Using Graph Theory

Modular robots are systems that can change its geometry or configuration when connecting more modules or when rearranging them in a different manner to perform a variety of tasks. Graph theory can be used to describe modular robots configurations, hence the possibility to determine the flexibility of the robot to move from one point to another. When the robots configurations are represented in a mathematical way, forward kinematics can be obtained.

ROBMAT: Teleoperation of a Modular Robot for Collaborative Manipulation

The present paper describes the architecture of a modular robot called RobMAT. A module description which includes both hardware and software features are shown. The module has 3 DoF which gives great functionality to the module. The connection between modules forms molecules. The simplest molecule is called base with 5 DoF. Channels of communication between modules (CAN bus) and molecules (Bluetooth) are also described. A method in representing molecule configurations based on Graph Theory is explained. This method allows developing algorithm for dynamically changing-robots such as modular robots. It also explains how the molecule is allowed to act as a whole synchronization algorithm. Finally a collaborative manipulation task, which is teleoperated, is shown. Elements involve in teleoperation are also described.

Cooperative task execution between modular robots based on tight-loose cooperation strategies

The complexity in the execution of cooperative tasks is high due to the fact that a robot team requires movement coordination at the beginning of the mission and continuous coordination during the execution of the task. A variety of techniques have been proposed to give a solution to this problem assuming standard mobile robots. This work focuses on presenting the execution of a cooperative task by a modular robot team. The complexity of the task execution increases due to the fact that each robot is composed of modules which have to be coordinated in a proper way to successfully work. A combined tight and loose cooperation strategy is presented and a bar-pushing example is used as a cooperative task to show the performance of this type of system.

Synchronizing a Modular Robot Colony for Cooperative Tasks Based on Intra-Inter Robot Communications

The implementation of robotic cooperative tasks such as pushing an object toward a desired destination or manipulating an object using mobile robots or robotic arms requires motion coordination between the robot colony. When a robot is built by the union of several robots, such as modular robot systems, it is critical to have the complete coordination of each robot configuration within the colony and also overall robot coordination of the colony. The paper presents a demonstration of parallel motion for modular robot configurations through the combination of two types of communications, i.e., Inter-robot and Intra-robot communications. The two types of communications are described and implemented in a real modular robot system. Experiments are executed to show the performance of the robot colony synchronization.

Modular robot based on 3 rotational DoF modules

This paper shows the advantages of having a modular system with 3-DoF spherical actuator in the base module to perform tasks that require displacement and object manipulation. Having 3-DoF actuator improves the complexity of coordination patterns and control algorithms of the modular system more relevantly as compared to having only 1 or 2DoF actuator in the module. Nevertheless, modules with actuators of only 1 or 2DoF require more modules to be assembled together in order to achieve complex tasks. Experiments performed with RobMAT modular system proves that a 3DoF actuator in the module is better, because tasks such as displacement, obstacle climbing and object manipulation, can be efficiently carried out with systems of 2 modules, 4 modules and 6 (maximum) modules connected together.

Transparency Analysis of Bilateral Controllers Based on the Methodology of State Convergence

This paper shows a new methodology for bilateral controller design based on transparency using a modified state convergence control scheme. This methodology offers some advantages upon designing bilateral systems. The design is based on modelling the behaviour of the master and the slave by applying state space equations, and considering perfect transparency cannot be reached. Therefore, the objective of the controllers is to guarantee the convergence of the master and slave status. This paper describes the criteria to achieve transparency on steady state.

Self-Alignment Approach Based on Cooperative Behaviors for the Docking Process of Modular Mobile Robots

In this paper, a self-alignment approach based on cooperative behaviors is proposed for the docking process of modular mobile robots. Each cooperative behavior is modeled by means of artificial neural networks (ANN) to achieve a common goal. Based on RobMAT a modular robot system in the mobile configuration, two strategies are presented. For this purpose a robotic device simulator (Player) and a multi-robot simulation in 2D (Stage) are used. Experimental results display differences between both strategies and benefits in time execution.