AUTONOMOUS LEGGED ROBOT

1. Developing the RS-01 RoboDog

What is claimed to be the world's most advanced, autonomous legged robot to be developed and marketed is called the RS-01 RoboDog. Produced with the aid of collaborative design software it is being marketed after less than a year's development and was available from April 2001 after its launch by its British developers, RoboScience.

Robotic technology can be used in several ways to benefit people with disabilities. This paper describes the mounting of a robotic arm to a powered wheelchair to assist disabled users in daily activities. Although there are many potential benefits for the disabled user, there are also very strong requirements and compromises, which must be considered in integrating the robotic arm with the wheelchair. This paper focuses on how these integration issues have been addressed.

This paper addresses an optimal study of workspace for spherical parallel mechanism for laparoscopic surgery. The spherical parallel manipulator has been selected because of its characteristics. Two designs have been studied for maximizing their workspaces; a haptic device, as part of training system, and a laparoscope holding mechanism. The laparoscope holding mechanism has to satisfy additional constraints by minimizing the occupied space above the patient. The objective is to solve design problem to offer the maximal workspace for such mechanisms. The design of a haptic interface and the laparoscope holding mechanism based on the optimal parameters are presented. This paper presents a Genetic Algorithm (GA) approach for selecting optimal design parameters for maximizing workspace of spherical parallel mechanism.

A method for searching the best location of a path in the robot workspace considering the velocity performance of the robot is presented. After a thorough investigation of the robot performance indices, a new measure for the velocity efficiency of a robot moving its end-effector along a path is introduced. This measure is an approximation of the minimum of the Manipulator Velocity Ratio (MVR) along the path. The minimum is calculated from a finite set of MVRs determined at specified points of the path using an algorithm for an approximate motion of the end effector along the path.

The introduced measure is used as the objective function in an optimisation problem, where an optimal location of the path is searched. The objective function is procedural and non continuous, so a Genetic Algorithm is used to search the space for the optimal location of the path. The proposed method is tested using a simulated PUMA-like robot, which has to move its end-effector along a straight-line segment. At the end of the paper, the results obtained in these tests are presented and discussed.

In this paper, we investigate trajectory tracking in a multi-input nonlinear system, where there is little knowledge of the system parameters and the form of the nonlinear function. An identification-based iterative learning control (ILC) scheme to repetitively estimate the linearity in a neighborhood of a desired trajectory is presented. Based on this estimation, the original nonlinear system can track the desired trajectory perfectly by the aid of a regional training scheme. Just like in adaptive control, a singularity exists in ILC when the input coupling matrix is estimated. Singularity avoidance is discussed. A new parameter modification procedure for ILC is presented such that the determinant of the estimate of the input coupling matrix is uniformly bounded from below. Compared with the scheme used for adaptive control of a MIMO system, the proposed scheme reduces the computation load greatly. It is used in a robotic visual system for manipulator trajectory tracking without any information about the camera-robot relationship. The estimated image Jacobian is updated repetitively and then its inverse is used to calculate the manipulator velocity without any singularity.

CaPaMan (Cassino Parallel Manipulator) is a 3-Degree Of Freedom spatial parallel manipulator that has been designed at the Laboratory of Robotics and Mechatronics, in Cassino. In this paper we present a formulation for an optimum design for CaPaMan architecture when the orientation workspace is suitably specified.

In this paper, the robust adaptive control and observer are considered for a pneumatic robot leg. This approach does not require a precise knowledge of the robot model physical parameters, only the adaptive upper bounds on the norm of the matrices model are used, which with the sliding mode guarantee the robustness of system. Convergence conditions and simulation results for the adaptive control and observer are presented.

Gripping of different types of objects with a multi-finger robot hand is a vital task for robot arms. Grippers, which are end effector elements in robot applications, are employed in various industrial operations such as transferring, assembling, welding and painting. However, if a gripper is considered for handling different jobs or to carry different types of parts in an assembly line, a general-purpose robot hand is going to be required. There are various technological actuators of robot hands such as electrical, hydraulic and pneumatic motors, etc. Besides these conventional actuators, it is possible to include Shape Memory Alloys (SMA) in the category of technological actuators. The SMA can give materials motion by moving to a predetermined position, at a specific temperature. The conversion of this motion to a gripping action of the robot hand is the heart of the matter. In this study, a robot hand is developed using Ni-Ti SMA and a set of experiments were performed in order to check the compatibility of the system in an industrial environment.

Three single-valued upper boundary functions for velocity, acceleration and deceleration of a wheeled mobile robot (WMR) are defined as closed mathematical forms over its entire spatial path. The limits deal with mechanical, kinematic and dynamic characteristics of the robot and with task and operating matters. These boundary functions can be computed making use of any robot model, as complex as is needed, since it works offline.

All studies are particularised for the robot RAM. A kinematic and a complete dynamic model of this WMR is built, with special attention on the study of wheel-ground contact efforts. For this purpose an empirical-analytical model of rubber wheel rolling is developed.

In this paper, we present a simple method to obtain joint inputs needed to attain any point in the reachable workspace of a class of five-bar planar parallel manipulators which are based on five rigid links and five single degree of freedom joints – revolute and prismatic joints. Depending on the topology of the manipulators, two mathematical expressions describing the path traced by the tip of two links connected to each other are obtained and solved simultaneously in order to determine the intersection points of the two paths which are the Cartesian coordinates of the connection points for the links. For the class of manipulators considered in this study, one of the links is the link activated by an actuator fixed to the ground. So, rotational and/or translational joint inputs can be determined from the Cartesian coordinates of the tip of the activated links. Sylvester's dialytic elimination method is employed to solve the equations. Such a methodology is easy to implement, computationally efficient and sound to compute all possible solutions. A numerical example is provided for each manipulator and the inverse position solutions are verified by substituting them into forward position equations. It is concluded that the proposed method is useful in trajectory planning and control of five-bar planar parallel manipulators in joint space.

Construction is of great interest in the application of practical and theoretical results in the field of robotics. The economic efficiency potential of using robots is defined by construction quantities, a high level of manual work, and hard and unfavorable working conditions. Mounting and finishing operations are the main focus for the practical use of robots. This paper describes technological characteristics of such operations, suggests kinematic structures for mounting and finishing operations, and provides kinematic model designs as examples. Taking into consideration the management details of mounting and finishing operations, this paper also makes recommendations on movement planning and on the formation of the laws of drive control. In the conclusion, recommendations on applying the results and using computer technologies in the development of control programs are presented.

A Wall-Climbing Robot (WCR) with magnetic tracks is presented in this paper. The robot is designed for labeling the scale of oil tank.5 The Wall-Climbing Robot (WCR) uses a permanent magnet sucker as its sucking mode, and a track as its moving mode. We designed an elastic brace mechanism, a load-scatter mechanism and parallelogram mechanism to improve the robot's adaptability on the steel wall surface. The control system utilizes two-level computer control systems, achieving control of the robot's moving track and processing data collected by the robot.

A control structure for the bilateral teleoperation of mobile robots, with tactile feedback and visual information of the interaction force is proposed in this paper. Also an impedance controller is implemented in the mobile robot structure that guarantees the linear velocity be within a desired fixed range without saturation in the actuators. To illustrate the performance of the proposed control structure, experiments on a Pioneer 2 mobile robot teleoperated with a commercial joystick with force feedback are shown.

Based on the author's knowledge the paper gives a brief account of some of the scientific achievements of robotics that were of crucial importance to its development.

In a rough chronological order these are: zero-moment concept and semi-inverse method; recursive formulation of robot dynamics; computer-aided derivation of robot dynamics in symbolic form; dynamic approach to generation of trajectories of robotic manipulators; centralized feedforward control in robotics; robot dynamic control; decentralized control and observer applied to strongly coupled active mechanisms; force feedback in dynamic control of robots; decentralized control stability tests for robotic mechanisms; underactuated robotic systems; practical stability tests in robotics; unified approach to control laws synthesis for robot interacting with dynamic environment; modeling and control of multi-arm cooperating robots interacting with environment; connectionist algorithms for advanced learning control of robots interacting with dynamic environment; fuzzy logic robot control with model-based dynamic compensation, and internal redundancy – a new way to improve robot dynamic performance.

Techniques for tele-operated robots have played for more than 30 years a major role in the context of space missions, as well as in monitoring and handling of hazardous materials. Recent progress in telecommunication and information processing technologies offers now an infrastructure for enabling the provision of services at remote locations with an enormous economic potential. The aim of this first IFAC-conference in telematics (= telecommunications+informatics) was to survey the state-of-the-art with emphasis on applications in automation and robotics. It was organised by the VDI/VDE Gesellschaft Mess-und Automatisierungstechnik (GMA) and the University of Applied Sciences FH Ravensburg-Weingarten.

6TH IFAC SYMP. ON COST ORIENTED AUTOMATION (LOW COST AUTOMATION 2001)

(Oct. 8–9, 2001, Berlin, Germany)

The symposium brought together researchers and industrialists in two plenary sessions, eight regular sessions and two industrial workshops (special sessions). The organizers intended to rescue Low Cost Automation from its bad reputation by considering mostly the development and application of cheap components of control systems of low performance, just suitable for developing industries. Because of this, the organizers intended to focus on considering and discussing cost-oriented or cost-effective solutions for automation systems. This intention was quite successful. Despite expensive components, the life cycle of automation systems regarding design, production, operating, maintenance, reconfiguration and recycling was cost effective (cost of ownership). The participants of the Industrial Workshops I and II on “Virtual Programmable Logic Control” and “Lifecycle Costs” presented and discussed new developments in these fields. As it turned out, companies are currently refraining from the implementation of highly automated svstems because they are too inflexible, and their maintenance and reconfiguration is too expensive. Companies are looking for cost-effective solutions. Additionally, the invited keynote speech of the second plenary session, “Maintenance Holistic Framework for Optimizing the Cost/Availability Compromise of Manufacturing Systems” stressed these problems.