In the authors' previous paper,10 an input shaping method was presented to reduce motion-induced vibrations effectively for various classes of flexible systems. In this paper, the effectiveness of the shaping method is experimentally demonstrated with a two-link flexible manipulator system

The manipulator for experiments includes two revolute joints and two flexible links, and moves on a vertical plane under gravity. An analytic model is developed considering the flexibility of the system and its joint stiffness in order to derive an appropriate estimation of dynamic modal properties. The input shaping method used in this work utilizes time-varying modal properties obtained from the model instead of the conventional input shaping method which employs time-invariant modal properties. A point-to-point motion is tested in order to show the effectivess of the proposed shaping method in vibration reduction during and after a given motion. The given reference trajectories are shaped to suppress the motion induced vibration. The test results demonstrate that the link vibration can be greatly suppressed during and after a motion, and the residual vibration reduction was observed more than 90% by employing this time-varying impulse shaping technique.

This paper investigates the feasibility of constructing a humanoid robot using existing technology. Firstly, the adoption of the humanoid form is justified. The structure, strength and power capabilities of a human are analysed in engineering terms, and taken to represent the requirements specification for a humanoid robot. Technological alternatives to the biological components are reviewed and compared to this specification. The feasibility of matching human performance is considered, and it is concluded that the necessary power and energy requirements can be fitted within the mass and volume of the human body.

We have designed a robotic arm based on a double parallel four bar linkage to act as an assistant in minimally invasive surgical procedures. The remote center of motion (RCM) geometry of the robot arm kinematically constraints the robot motion such that minimal translation of an instrument held by the robot takes place at the entry portal into the patientApos;s body. In addition to the two rotational degrees of freedom comprising the RCM arm, distal translation and rotation are provided to manoeuver the instrument within the patient's body about an axis coincident with the RCM. An XYZ translation stage located proximal to the RCM arm provides positioning capability to establish the RCM location relative to the patients anatomy. An electronics set capable of controlling the system, as well as performing a series of safety checks to verify correct system operation, has also been designed and constructed. The robot is capable of precise positional motion. Repeatability in the ±10 micron range is demonstrated. The complete robotic system consists of the robot hardware and an IBM PC-AT based servo controller connected via a custom shared memory link to a host IBM PS/2. For laparoscopic applications, the PS/2 includes an image capture board to capture and process video camera images. A camera rotation stage has also been designed for this application. We have successfully demonstrated this system as an assistant in a laparoscopic cholecystectomy. Further applications for this system involving active tissue manipulation are under development.

A novel off-line technique for automatic calibration of kinematic parameters for hydraulic manipulators is presented. Hydraulically actuated manipulators have joints which are always powered and, unlike conventional robots, may not have conventional joint sensors to exploit in the calibration procedure. Instead, our approach employs an external three-dimensional linkage, termed “the calibrator”, which has sufficient number of joints with corresponding sensors. One end of the calibrator is grasped by the manipulator's end effector while the other end is attached to a passive spherical joint fixed to the world coordinate system. The mobile closed kinematic chain thus formed has the added advantage of eliminating the explicit measurement of the manipulator's endpoint location. A sequential identification technique that uses a least squares numerical search algorithm has been developed based on link-by-link movement of the manipulator. Simulation and experimental calibration results on a typical mobile hydraulic manipulator are reported in this paper, which show that the proposed technique is globally stable, and potentially fast, inexpensive, and easy to apply on site.

The paper focuses on the problem of trajectory planning of multiple coordinating robots. When multiple robots collaborate to manipulate one object, a redundant system is formed. There are a number of trajectories that the system can follow. These can be described in Cartesian coordinate space by an nth order polynomial. This paper presents an optimisation method based on the Genetic Algorithms (GAs) which chooses the parameters of the polynomial, such that the execution time and the drive torques for the robot joints are minimized. With the robot's dynamic constraints taken into account, the pitimised trajectories are realisable. A case study with two planar-moving robots, each having three degrees of freedom, shows that the method is effective.

Local torque minimization for redundant manipulators has been considered by using a redundancy resolution approach. Since its initial formulation, however, proposed solutions have been plagued by performance instabilities. Till now, the reason was not clear. In this paper it is shown that the instability problem occurred because of incorrect formulation. A correct formulation is proposed, which is used to analyze the reason for instability. Special attention is paid to joint acceleration terms at the selfmotion manifold. This helps explaining the recent formulation of a stable scheme based on local joint velocity minimization in terms of torque. The results obtained. are related to dynamic redundancy resolution in general.

The dynamic model of an articulated vehicle consisting of one tractor and two semi-trailers is derived according to a systematic approach available in the literature. The model is produced on the assumption of no slippage, which enforces nonholonomic constraints. The resulting equations encompass a number of significant special cases.

A grid-based method for detecting moving objects is presented. This method involves the extension and combination of two methods: (1) the Hough Transform and (2) the Occupancy Grid method. The Occupancy Grid method forms the basis for a probabilistic estimation of the location and velocity of objects in the scene from the sensor data. The Hough Transform enables the new method to handle non-integer velocity values. A model for simulating a sonar ring is also presented. Experimental results show that this method can handle objects moving at non-integer velocities.

To solve manipulation problems when fast transportation operations are combined with high precision positioning operations, an approach to telerobotic system organization with manipulator variable parameters is presented. It is proposed that the human operator should personally adjust the robot parameters in compliance with the situation requirements. Therefore, an additional channel of parameter control was introduced into the system. The approach results in the organizing of highly effective on-line systems with sufficiently simple control algorithms.

A knowledge of the fabric material and its properties, mechanisms of prehension and an understanding of sensor and manipulator integration are essential for even the most basic of robotic textile handling tasks. This paper considers individually, and as a combination, the aspects of mechanical and electrical hardware, software and logistics necessary in making automated fabric ply separation and positioning possible.

This paper deals with the problems of the education of the staff in robotics and flexible automation at the secondary school level. It deals with an experiment which aims at training technicians for robotics and flexible manufacturing systems. The experiment began in 1989. and now the second generation of students that studies according to the curricula of this experiment has completed the education. Previous experience, especially from the standpoint of the result of the students and problems that arise during the realization of the experiment, are analyzed in this text.

The main objective of this paper is a presentation of an experimental identification of a non-direct drive robot and load dynamic parameters, which appear in the integral model. The last one is based on the energy theorem formulation. In the robotics literature there are not many experimental results known to the authors, concerning the identification of the dynamic parameters of different models. In order to satisfy this, the experimental system has been built around an industrial ASEA IRp-6 robot. In this paper we propose to precompute the friction characteristics which are separated in the integral model. Various aspects of the exciting trajectories are considered. It is shown how to identify the friction coefficients using a short integral model. The experimental results are presented, including comparison of the results for both integral and differential identification. The identified models are verified by computing the predicted torques and trajectories

Learning in the age of information superhighway necessitates a properly-developed efficient vehicle that is not only powerful in directing users to the needed information or to situate in a reality through virtual settings, but also controllable at the various comfortable paces. The goal of this project is to explore a new on-line medium for users to navigate at their own pace in the structured cyberspace—knowledge space composed of concepts, systems design, application-oriented case studies, up-to-date industrial news (trends and product review), and on-line robotic systems, and to use it as a robotics work-bench for conducting controllable experiments/simulations. Through such an electronic learning medium, users will be able to acquire a global outlook as well as an integrated understanding of modern robotics in a manner that is low-cost, time-and-place-free, and student-centered.