Amir Ali Forough Nassiraei

Concept and Design of A Fully Autonomous Sewer Pipe Inspection Mobile Robot "KANTARO"

In current conventional method, the sewer pipe inspection is undertaken using a cable-tethered robot with an on-board video camera system, completely, tele-operated by human operator. All commercial sewer inspection robots have platforms with poor mobility functions so that those robots are only capable to move into the straight pipes. Inspecting the sewage pipes using the state of the arts inspection methods by the current robots is costly, mostly human cost, and not fast enough to check and inspect the amount of sewage pipes will grow stronger than it has actually happened, specially in Japan. In order to realize inexpensive and effective inspection system, an autonomous pipe inspection method should be introduced to improve the inspection efficiency by reducing the time and manpower in the inspection process. The development of a fully autonomous pipe inspection system, requires design and development of an un-tethered mobile robot equipped with the required sensors using for autonomous pipe assessment and damage detection, and capability of navigating, completely, autonomously inside of sewer networks including different types of pipe-bends such as curves and junctions. KANTARO, presented in this paper, is the prototype of a passive-active intelligent, fully autonomous, un-tethered robot which has an intelligent modular architecture in its sensor and mechanism. KANTARO prototype robot, including a novel passive-active intelligent moving mechanism, can move into the straight pipe and pass various kinds of pipe bends without need to any intelligence of the controller or sensor reading. In order to realize a fully autonomous inspection robot, we also developed a small and intelligent 2D laser scanner for detecting of the navigational landmarks, independently with the main computer system, and fusion with a fish eye camera to assess the pipe state and fault detection.

A study of an autonomous mobile robot for a sewer inspection system

This article describes a prototype autonomous mobile robot, KANTARO, designed for inspecting sewer pipes. It is able to move autonomously in 200–300-mm-diameter sewer pipes, to turn smoothly through 90° at a junction, and to go down a 5-cm step. KANTARO carries all the resources required, such as a control unit, a camera, a 2D laser, and an IR sensor. Damage or abnormalities in sewer pipes are detected based on recorded sensory data. KANTARO has demonstrated its effectiveness in inspection and in autonomous navigation in a dry sewer test field at the FAIS–Robotics Development Support Office (FAIS–RDSO).

Concept of Intelligent Mechanical Design for Autonomous Mobile Robots

The concept of Intelligent Mechanical Design (IMD) is presented to show how a mechanical structure can be designed to affect robot controllability, simplification and task performance. Exploring this concept produces landmarks in the territory of mechanical robot design in the form of seven design principles. The design principles, which we call the Mecha-Telligence Principles (MTP), provide guidance on how to design mechanics for autonomous mobile robots. These principles guide us to ask the right questions when investigating issues concerning self-controllable, reliable, feasible, and compatible mechanics for autonomous mobile robots. To show how MTP can be applied in the design process we propose a novel methodology, named as Mecha-Telligence Methodology (MTM). Mechanical design by the proposed methodology is based on preference classification of the robot specification described by interaction of the robot with its environment and the physical parameters of the robot mechatronics. After defining new terms, we investigate the feasibility of the proposed methodology to the mechanical design of an autonomous mobile sewer inspection robot. In this industrial project we show how a passive-active intelligent moving mechanism can be designed using the MTM and employed in the field.

Control of robotic joint by using antagonistic pair of Twist Drive Actuators

In this paper we present a control method for robotic finger that uses twisted strings actuator called Twist Drive. A five fingered robotic hand prototype was developed by using Twist Drive actuators to control 14 active degrees-of-freedom. This paper focuses on control of a thumbs CM joint, which is the only joint in the robotic hand prototype that uses two Twist Drive actuators configured in an antagonistic pair of actuators. Positioning accuracy and smoothness of the joints motion is influenced by nonlinear characteristics of the actuators and by friction in the mechanism. To compensate for the disturbances, we used disturbance observer, and additionally enhance smoothness of motion by controlling the unwinding torque of opposing actuator. The robotic hand and the proposed control algorithm are explained in the paper, experimental results of CM joint positioning control are presented.

A System Design Concept Based on Omni-Directional Mobility, Safety and Modularity for an Autonomous Mobile Soccer Robot

In this paper, we describe the concept, design and implementation of a series of autonomous mobile soccer robots, named Musashi robots, which are designed referring ISO safety standards and have mechatronics modular architecture. The robots are designed to participate in the RoboCup Middle Size League. Using a modular design philosophy, we show that the selection of a proper moving mechanism, a suitable vision system and a mechatronics modular architecture design can lead to the realization of a reliable, simple, and low cost robot when compared with most car-like robots that include many kinds of sensors and have a complex design structure.

An artificial potential field based mobile robot navigation method to prevent from deadlock

Abstract Artificial Potential Filed (APF) is the most well-known method that is used in mobile robot path planning, however, the shortcoming is that the local minima. To overcome this issue, we present a deadlock free APF based path planning algorithm for mobile robot navigation. The Proposed-APF (P-APF) algorithm searches the goal point in unknown 2D environments. This method is capable of escaping from deadlock and non-reachability problems of mobile robot navigation. In this method, the effective front-face obstacle information associated with the velocity direction is used to modify the Traditional APF (T-APF) algorithm. This modification solves the deadlock problem that the T-APF algorithm often converges to local minima. The proposed algorithm is explained in details and to show the effectiveness of the proposed approach, the simulation experiments were carried out in the MATLAB environment. Furthermore, the numerical analysis of the proposed approach is given to prove a deadlock free motion of the mobile robot.

Development of Ship Hull Cleaning Underwater Robot

The sea transportation by ships covers most of trade volume, and the technologies for fuel efficiency and reductions of carbon-dioxide emissions should be developed. One of the technical issues to improve fuel efficiency of ships is how to prevent the marine biofouling to the ship hulls and remove organisms from ships. In general, the cleaning of ship hull is carried out on the ship inspection in dock yard or by divers in harbor. Frequent cleaning of ship walls is desirable to keep good fuel efficiency, however, the ship inspection on dock is done once a year and the cleaning by divers is high-cost and involve high risk. One of the solutions to the problem is the introduction of underwater robots to clean ship surfaces. In this paper, an underwater robot for ship hull cleaning is proposed and examined through ship hull cleaning experiments.

Power and propulsion systems design for an autonomous omni-directional mobile robot

In this paper power and propulsion systems design for an autonomous omni-directional mobile robot which is developed for RoboCup compaction, is presented. For robot energy storage unit, lithium ion polymer battery is chosen because of its high power and energy densities, and a protection circuit against deep battery discharge was designed for it. Because the power flow between energy storage units and motors and also speeds of motors have to be controlled at the same time, we proposed a two cascaded cell modules consisting motor speed control and power flow control modules. The other parts of our robot power system are dc-dc converters and kicker circuit. The simulation and experimental results show proposed scheme is valid and energy management and speed control can be achieved properly using this method. The filed experiments show robot mobility functions to perform the requested motion is enough and it has a high maneuverability in the field.

Modification of electric drive vehicles performances using a direct torque control with over-modulation ability

In electric and hybrid-electric vehicles, the inverter output voltage is limited by available DC-link voltage, which restricts the vehicle speed and acceleration. Therefore the fundamental component of the motor voltage should be increased by operating inverter in the six-step mode at high speeds. Although hysteresis based direct torque control (DTC) is a straightforward approach and has several advantages, this method cannot work in the six-step mode. In this paper a new hysteresis based DTC with over modulation ability for interior permanent magnet synchronous machines (IPMSM) is suggested. In this method, unlike the previously proposed methods, the calculation of the voltage vector or flux reference in different phase angles is not necessary. In the proposed method, the flux trajectory is changed by adjusting the non-switching area and modifying switching table, and thus a seamless transformation between high-frequency switching and six-step square wave is possible. Also in this paper, the dynamic model for an electric vehicle is developed which its traction motor is controlled by proposed DTC. The simulation results prove that the proposed method modify the vehicle performances, notably. These results show that the vehicle with proposed method has a higher top speed and better acceleration. Also it is shown, that the proposed method can improve the vehicle efficiency for various driving cycles. In addition the results confirm the torque discontinuity does not appear in the whole range of vehicle speed.

A Novel Embedded Computer Based Autonomous Robot for Sewer Pipe Inspection

In this paper, in order to realize an effective inspection system, an embedded computer based autonomous pipe inspection robot is presented. This robot is designed as a fully autonomous, un-tethered robot, which fits to the pipes within a diameter range of 200- 300 millimeters. The practical field tests show that the robot performs well and can do pipe inspection properly and the robot moves gracefully not only at straight paths but also at junctions and curves.