In this paper an inverse concept idea is presented to determine the main configuration dimensional parameters of a novel 5-DOF parallel kinematic machine tool. By the new described orientation workspace, the motion of the passive joints on the moving platform can be expressed in the fixed coordinate analytically. Some relationships between the reachable workspace and the dimensional parameters of the parallel machine tool have been obtained with graphical representation.

Rotational data in the form of measured three-dimensional rotations or orientations arise naturally in many fields of science, including biomechanics, orthopaedics and robotics. The cyclic topology of rotation spaces calls for special care and considerations when performing statistical analysis of rotational data. Relevant theory has been developed during the last three decades, and has become a standard tool in some areas. In relation to the study of human kinematics and motion however, these concepts have hardly been put to use. This paper gives an introduction to the intricacies of three-dimensional rotations, and provides a thorough geometric interpretation of several approaches to averaging rotational data. A set of novel, simple operators is presented. Simulations and a prosthetics-related real-world example involving wrist kinematics illuminate important aspects of the results. Finally generalizations and related subjects for further research are suggested.

In this paper a framework is proposed for the adaptive control of robotic manipulators which combines parametric adaptive control with Artificial Neural Network (ANN)-based compensation of dynamic uncertainties like friction. The proposed method utilizes a passivity-based parametric adaptive control approach and makes use of the ANN models as generic identifiers to compensate for unmodelled friction effects. Unlike many approaches for ANN based control in the literature, parameter update equations for the ANN model and for the parametric adaptive model are driven by both the tracking error and the system identification error. A stability analysis is given based on the passivity properties of the manipulator dynamics. The methodology is successfully tested for the control of a Direct Drive SCARA arm and performance is compared with standard adaptive control schemes.

A planar underactuated bipedal robot with an impulsive foot model is considered. The analysis extends previous work on a model with unactuated point feet of Westervelt et al. to include the actuator model of Kuo. The impulsive actuator at each leg end is active only during the double support phase, which results in the model being identical to the model with unactuated point feet for the single support phase. However, the impulsive foot actuation results in a different model for the double support map. Conditions for the existence of a hybrid zero dynamics for the robot with foot actuation are studied. A feedback design method is proposed that integrates actuation in the single and double support phases. A stability analysis is performed using a Poincaré return map. As in Kuo's model, a more efficient gait is demonstrated with an impulsive foot action.

In this paper, we study the base placement problem for a two-degree-freedom-robot. The feasible area for the robot base is described, and its manipulability measure is formulated. To find the optimal base location of the robot, we develop a genetic algorithm (GA) to search for the valid solution in the reachable area of the robot base. To speed up the evolutionary process, we keep the elitists from one generation to the next generation according to certain elitist rate. The genetic algorithm approach is beneficial because it can also be extended to trajectory planning for robots with more degrees-of-freedom. We demonstrate the algorithm with some examples.

In this paper, the design and control of an omni-directional mobile microrobot are described for micro-assembling in a micro-factory. A unique locomotion mechanism composed of three special castors units is proposed. The castor consists of two coaxial conventional wheels, connected to the chassis and connected with each other by a set micro-gears. The microrobot is approximately 8 mm in length, 6 mm in width and 6 mm in height. Its kinematics and characteristics are analyzed. Experimental results from a prototype of a microrobot are presented, which demonstrates the feasibility of building an omni-directional microrobot with micromotor and special castors.

Optical tweezers have been used as versatile tools for non-contact manipulation of micrometer-sized entities. This paper proposes a hybrid micro/nanoscale manufacturing system using optical tweezers and chemical linkages for fabricating 2D and 3D micro/nanostructures. A holographic multiple trap optical tweezers system is first used to trap particles in a desired pattern. The particles are then connected to form rigid units using suitable chemistry. Connection schemes based on gold seeding, complementary-DNA linkage and streptavidin-biotin chemistry are presented and possible applications of this technique are explored. This method combines the advantages of top-down and bottom-up approaches and is compatible with organic and inorganic materials.

In this paper a new prosthetic hand is presented that closely approximates the grasping abilities of a human hand. A large variety of different objects can be grasped reliably and the movements of the hand appear to natural. This five-finger hand has 15 degrees of freedom driven by small sized flexible fluidic actuators. The drives are within the fingers allowing a very compact and lightweight hand. Also, a concept for the control of different grasp types is presented. The characteristics of the new hand are illustrated.

This paper deals with a method for robot navigation towards a moving goal. The goal maneuvers are not a priori known to the robot. Our method is based on the use of the kinematics equations of the robot and the goal combined with geometrical rules. First a kinematics model for the tracking problem is derived and two strategies are suggested for robot navigation, namely the velocity pursuit guidance law and the deviated pursuit guidance law. It turns out that in both cases, the robot's angular velocity is equal to the line of sight angle rate. Important properties of the navigation strategies are discussed and proven. In the presence of obstacles, two navigation modes are used: the tracking mode, which has a global aspect and the obstacle avoidance mode, which has a local aspect. In the obstacle avoidance mode, a polar diagram combining information about obstacles and directions corresponding to the pursuit is constructed. An extensive simulation study is carried out, where the efficiency of both strategies is illustrated for different scenarios.

Underwater Modular Self-Reconfigurable (UMSR) robots, made up of many identical modules, can adjust their configurations to multiple underwater environments or tasks. They can be used in many complex underwater occasions where the ROVs/AUVs can't work well. However, their reconfiguration is difficult because this has to involve many connection adding and removing operations which are difficult to be executed in the underwater environment. To reduce the times of these operations, we propose the theory of Topological Transformation (TT), which includes some definitions in TT, the basic approach to TT, and the Genetic Algorithm (GA) based solution for the optimal TT.

In this paper, different adaptive control algorithms will be experimentally tested on a two axis SCARA type direct drive robot arm, and the performance of these algorithms will be compared. Being a direct drive system, the nonlinear effects, arising from the dynamics of the manipulator under high velocities, are directly reflected in the control of the manipulator. This makes the manipulator a more efficient test bed for testing the efficiency of the proposed adaptive schemes. In the experiments, we used fast trajectories rather than slow ones to observe how the proposed controllers compensate the dynamic nonlinear effects of manipulator dynamics. We will test some known adaptive control algorithms given in the literature along with our proposed adaptive control scheme which makes use of multiple models.

Isolation and separation of the target microbe or cell from a large heterogeneous population is quite important. We propose a new touch sensor that is used for the separation of the target microbe with a pipette. This sensor is sensitive enough to protect the fragile pipette tip from abrupt collision. Using this sensor, we developed a novel separation system for screening a target microorganisms from the randomly distributed samples in the dish with the local viscosity control of the thermosensitive hydrogel. With this system, the target yeast cell was extracted successfully.

This paper presents a new haptic device based on a parallel structure that can be used as a master interface in a teleoperation or haptic control architecture. The basic idea of a haptic device is to serve force and/or position reflection to the operator; at the same time that is being used by the human operator to input the required commands. The original mechanical structure of the presented system implies important advantages over other existing devices. The mechanism is a modification of the 6-d.o.f. Gough platform where the linear actuators have been replaced by cable-driven pantographs. Avoiding the use of reduction gears by means of cable transmission allows a wide sensing bandwidth. Some experimental indices comparing the performance of the presented device are presented. The paper shows the geometrical model and the kinematic analysis used on the control algorithms of this interface. The hardware and software architectures used on the system, and the control schemes implemented on a multi-axis board, are detailed. This setup provides an open control architecture that allows the implementation and experimentation of several bilateral control schemes. The integration of the haptic device in a teleoperation simulator is shown. This simulator includes virtual robotic slaves and its dynamic interaction with the virtual environment. Finally, the results obtained in the virtual objects manipulation experiments are shown. A classical force-position bilateral control scheme was used for these experiments.

This paper describes a simulation model for a multi-legged locomotion system with joints at the legs having viscous friction, flexibility and backlash. For that objective the robot prescribed motion is characterized in terms of several locomotion variables. Moreover, the robot body is divided into several segments in order to emulate the behaviour of an animal spine. The foot-ground interaction is modelled through a non-linear spring-dashpot system whose parameters are extracted from the studies on soil mechanics. To conclude, the performance of the developed simulation model is evaluated through a set of experiments while the robot leg joints are controlled using fractional order algorithms.

In this paper, we propose a model-based control system design for autonomous flight and guidance control of a small-scale unmanned helicopter. Small-scale unmanned helicopters have been studied by way of fuzzy and neural network theory, but control that is not based on a model fails to yield good stabilization performance. For this reason, we design a mathematical model and a model-based controller for a small-scale unmanned helicopter system. In order to realize a fully autonomous small-scale unmanned helicopter, we have designed a MIMO attitude controller and a trajectory controller equipped with a Kalman filter-based LQI for a small-scale unmanned helicopter. The design of the trajectory controller takes into consideration the characteristics of attitude closed-loop dynamics. Simulations and experiments have shown that the proposed scheme for attitude control and position control is very useful.

The design of multifunctional upper limb prosthetics has been investigated in recent years. In 1998, the MANUS consortium was set up on the basis of multidisciplinary skills of the partners in order to provide a global approach to the problem of upper limb prosthetics. In the framework of this approach, the consortium addressed the development of appropriate hand mechanics, the analysis and implementation of control electronics, the development of advanced control strategies and the implementation of broad band command interfaces based on EMG.

As a result, the prototype of a multifunctional prosthesis was developed, integrated and clinically evaluated. This paper describes the objectives, technological approach and results of the MANUS prosthesis prototype.

This paper describes a project to implement necrophoric bee behaviour in a robot swarm. Pheromone communication is an effective means of coordinating the activities of insect colonies including food gathering, alarm and defense, reproduction and recognition of conspecifics. In a similar manner it is anticipated that pheromones will provide a valuable form of communication between robots. In order to investigate the problems and potential for this form of interaction, it was decided to implement an example of pheromone communication in a physical robotic system. Inspiration for this project came from the necrophoric behaviour of bees. The necrophoric pheromone released by dead bees triggers corpse removal behaviour in passing worker bees. In the context of a robot swarm one of the proposed applications for this behaviour is to locate and rescue disabled robots that release a pheromone as a form of distress signal. This paper provides details of the swarm robots used in the project, their sensors and the simple reactive control algorithm that was developed to mimic the necrophoric behaviour of bees. Results of practical experiments and simulations are also given.

In this work, the elementary task of controlling the contact of a one degree-of-freedom (dof) robot with a compliant surface is modeled as a switched system. A position controller is used for the free motion and a force controller for the contact task and the goal is to stabilize the robot in contact with the spring-like environment while exerting a desired force. As the robot makes or breaks contact, the control law switches accordingly and the aim is to examine the system's stability using ideas from hybrid stability theory. By considering typical candidate Lyapunov functions for each of the two discrete system states, conditions on feedback gains are derived that guarantee Lyapunov stability of the hybrid task. It is shown that conditions can be decoupled with respect to the discrete state only when the more general hybrid stability theorems are used.

We consider the problem of the stabilization in single support of the vertical posture for a two-link, a three-link, and a five-link planar biped without feet. The control torques are applied in the inter-link joints only. Thus, our objects are under-actuated systems. The control laws are designed, using the biped linear models and their associated Jordan forms. The feedback is synthesized to suppress the unstable modes. The limits imposed on the torques are taken into account explicitly. Thus, the feedback laws with saturation are designed. The numerical investigations of the nonlinear models with the designed control laws are presented.

This paper extends the models developed previously by the authors for simulating tip-over stability of mobile manipulators, to include the friction of the contact between the base and the ground. Thus, the present model takes into account the detailed dynamics of the base that can rock back and forth during the movement of the manipulator, the combined vehicle suspension and ground-tire compliance and, the friction between the wheels and the ground. ‘LuGre’ tire friction model is employed, which along with the novel method of virtual links transforms the system into a fixed base manipulator with single degree of freedom at each joint. The model is then used to simulate planar movements of a 215B Caterpillar excavator-based log-loader machine. The results are also compared to those obtained by the simplified model, which was developed previously based on the assumption that the friction between the base and the ground is high enough to prevent the base from skidding forward or backward. The results clearly show that the friction properties between the wheels and the ground affect machine stability. Thus, one has to include the frictional effect in order to accurately predict the tip-over behavior of mobile manipulators.