With growing demand for health care, medical clinicians and researchers need to gather quality patient centric data in order to better develop tools to improve quality of life. As an example, it has been a challenge to accurately evaluate postoperative mobility in patient care units. This paper describes the development and implementation of a proof-of-concept, a low cost and easily deployable Bluetooth Low Energy (BLE) based localization system used to identify and locate patients. Using the received signal strength (RSS) of BLE signal and the uniqueness of BLE hardware addresses, patients can be identified and located within the hospital room. The value of RSS of BLE signal from wearable BLE beacon varies with distance to the wall anchored BLE scanner. The first part of the paper presents the results of the experiments conducted in a low noise and non-reflective environment. The second half of the paper talks about the proposed algorithm of localization of the subject within the experimental room. The paper evaluates the effects of the number of BLE wall anchored scanners and the number of packets on the accuracy of the proposed algorithm. The proposed algorithm was evaluated to have better performance than other classical approaches.

It is a well-know statistics that the percentage of our elderly population will globally surpass the other age groups. Majority of the elderly would still prefer to keep an active life style. In support of this life style, various monitoring systems are being designed and deployed in order to have a seamless integration with the daily living activities of the elderly while preserving various levels of their privacy. Motion tracking is one of these health monitoring systems. When properly designed, deployed, integrated and analyzed, they can be used to assist in determining some on-sets of anomalies in elderly health at various levels of their movements and activities. In this paper, we propose to divide the overall motion tracking of the elderly into three levels were at each hierarchical level, information regarding movement patterns can be analyzed ranging from global motion patterns to more detailed gait patterns. Depending on the state of frailty of elderly, this hierarchical break-downs can allow the medical personnel and physicians options for deploying sensing system which offers different degree of granularity in motion sensing. These levels are defined as: a) coarse global path of mobility between various key nodal points in the monitoring area; b) the trajectory of motion between each of the key nodal points and c) the gait patterns along the motion trajectories between the key nodal points. In this paper we presents an overview of these levels and associated tools which can be utilized in order to further explore and define motion patterns that can be utilized by data scientists and medical personnel as a part of the prevention analysis.

This paper explores the novel use of multiple depth sensors to overcome occlusions and improve localization and tracking of body extremities. The usage of data from only depth sensors not only overcomes visual challenges associated with RGB sensors under low illumination, but also protects the identity of surveyed person with high confidentiality. For integrating depth information from multiple sources, the paper presents first an overview of a novel calibration method for multiple depth sensors. In case of occlusion of any fiducial point in the primary sensor's depth image, co-ordinates of the point can be obtained from the frame of other sensors using the calibration parameters. To localize salient body parts such as hands, head and feet, a surface triangular mesh is applied on generated 3D point cloud from the primary sensor. The geodesic extrema from the mesh coincide with body extremities. The body extremities can be identified based on those relative geodesic distances between the extremities. Once the body parts are labelled, a portion of body can be targeted and evaluated for specific gait analysis and visualization. For the performance evaluation, our calibration method has fared well in comparison to other available techniques. Also, our proposed localization of salient body parts is able to successfully tag the specific body part i.e. the head region.

In this paper, we propose a novel method to estimate the posture of the human body in a network of depth sensors. We divide the body into two regions and take a limited number of selective samples from point cloud of human body. The sample points are utilized to compute 2D gradient and the histograms of the gradient of sample points along two different scan directions. These extracted values are then selected as feature points of each posture which are then compared with stored values for further posture classification. The input depth map is assigned to a known posture having the most similarity among all available samples. It is shown that the proposed approach offers high recognition rate despite low number of training set.

This paper investigates the integration of multiple time-of-flight (ToF) depth sensors for object reconstruction. The advantage of such a sensor network is in the increased viewing coverage and addressing the problem of object self-occlusion. However, in utilizing a network of depth sensors, calibration and interference between the sensors can be one of the key challenges of their effective utilization. In comparison with infrared depth sensors, integration of time-of-flight sensors offer some new challenges. This paper presents experimental studies of practical factors that can affect such integration and proposes a guideline which can be used to avoid interferences. Using the proposed set-up, the paper also presents a method which can be used for reconstructing objects in such a sensor network.

This paper investigates the limits of vibrato tactile haptic feedback when interacting with 3D virtual scenes. In this study, the spatial locations of the objects are mapped to the work-volume of the user using a Kinect sensor. In addition, the location of the hand of the user is determined using marker-based visual processing. The depth information is used to build a vibrotactile map on a finger of a haptic glove enhanced with vibrating actuators. The users can perceive the locations and dimensions of remote objects by moving their hand inside a scanning region. A marker detection imaging can provide the location and orientation of the user hand (glove). In order to map the corresponding tactile message. A user study was conducted to explore how different users can perceive such haptic experience. Factors like total number of detected objects, object separation spatial resolution, dimension-based and shape-based discrimination were evaluated. The preliminary results in a group of untrained users of different ages and backgrounds showed that the localization and counting of objects can be attained with a high degree of success. All users were able to classify groups of objects based on different dimensions (height, width, deep) and the perception of total volume. However, shape recognition proved to be a challenge for the majority of the users using the current configuration of the haptic glove.

In recent years, design and development of a practical force signal processing schemes which can be used for remote control of robotic devices over the Internet has gain a considerable attention. Traditionally, various local closed-loop control methodologies were proposed based on the two-port network architecture. Main concerns for this type of bi-lateral telemanipulation have been the stable tracking of the transmitted force and position signals. As such, assumptions have been made in regard to no loss of the transmitted information and existence of a fixed time delay between the master robot and the slave environment. However, connectivity through Internet introduces variable time delays with added lost of information. Not until recently, most of the proposed control methodologies have ignored taking advantage of the nature of the Internet protocols and its associated signal processing. For example, the limits of human tactile/force perception on distinguishing temporal changes in force signal can introduce a feasible and practical constraint which can be incorporated in the framework of single processing and in the data communication transport. This paper presents an overview of the literature on user-centered Internet-based tele-operation and proposes a force signal processing framework which can be utilized in such implementation.

In this paper, we present a forward error correction method to improve reliability of bilateral teleoperation systems or haptic interfaces over the unreliable network. Based on the digitization of haptic data, the proposed error correction method can be processed within a sampling period, which ensures a real-time process for bilateral teleoperation systems or haptic interfaces. An experimental study is performed using a haptic interface that is interacted with a virtual environment through the communication network. We conduct a psychophysical evaluation to determine the required bit resolution for the haptic data digitization method. Given the psychophysical evaluation result, we present a reliability evaluation of the proposed forward error correction method under the packet loss behavior over the communication network in addition to the noisy environment.

This paper proposes a multi-camera surveillance framework based on multiple view geometry. We address the problem of object association and consistent labeling through exploring geometrical correspondences of objects, not only in sequential frames from a single camera view but also across multiple camera views. The cameras are geometrically related through joint combination of multi-camera calibration, ground plane homography constraint, and field-of-view lines. Object detection is implemented using an adaptive Gaussian mixture model, and thereafter the information obtained from different cameras is fused so that the same object shown in different views can be assigned a unique label. Meanwhile, a virtual top-view of ground plane is synthesized to explicitly display the corresponding location and label of each detected object within a designated area-of-interest.

This paper presents experimental studies for increasing transparencies in haptic interaction. In particular, the experimental results of this paper are concerned with the new design and the prototype of a 6DOF haptic device. This device consists of a passive/active spherical joint and the connecting serial link mechanisms. The gravity compensation is accomplished both mechanically and through feed-forward compensation. The passive spherical joint can mechanically compensate for the gravity loading of the spherical active links and the associated connected serial mechanism to the floating platform. It is shown that through implementation of passivity-based controller, closed-loop stability of the system can be achieved when interacting with increased stiffness of the virtual environment.

This paper presents a control strategy to the pursuit problem of an intruder with evasive as well as nonevasive behavior. In present approach, the decision-making process is sub-divided into individual agents' ranking over the available task space and group level inference. A novel ranking mechanism embedded within individual members of pursuit team enables robots to determine their own rankings on available task space, taking into account agent's internal as well as external states. While such decision engine provides autonomy to individuals at every decision cycle, the central mediation unit prevents any contingent mission failure that may incur due to uneven distribution of agents over available task space, via mediating the individuals' decisions. Properties that can be attributed to one such system are investigated. Simulation results and performance analysis of the proposed approach for evasive as well as nonevasive intruder are demonstrated.

We propose a multi-robot task-allocation strategy in which individuals' task assignments are carried out through the application of iterative permutations of agents' cost values that are associated with completing given tasks. Different possible permutations of agent-to-task assignments are calculated based on profile matrix that comprises all robotic agents' costs with regards to available tasks. The permutations that are calculated off-line are next used at runtime to dynamically and as per states of agents and available tasks ascertain the optimal agent-task allocations at every decision cycle. Proof of optimality of the adapted allocation strategy is presented. Performance of the proposed approach in multi-robot dynamic multi-task allocation scenario is demonstrated.

In this paper, we present the performance evaluation of haptic compression methods for networked teleoperation systems or haptic interfaces in virtual environments. Haptic data, which include position, velocity, and force data exchanged through the communication channel, are considered by various compression methods based on down-sampling. We introduce the operational rate-distortion performance measure that evaluates not only the compression ratio, but also the quality of reconstructed haptic data. The deadband method, also known as a perception-based haptic compression method, is categorized as an adaptive down-sampling method and compared with a fixed rate down-sampling method. In the case of force data compression, we propose the modified deadband method, which adopts a force predictor, a quantizer, and a contact force detector. Experiments are performed by using a haptic device incorporated with a virtual teleoperator. The performance evaluation and comparison of the fixed rate down-sampling, deadband, prediction-based deadband, and modified deadband methods are provided. The results show that the proposed method achieves improvement in the compression ratio and quality measurement compared to other methods.

In this paper, we present a Bayesian prediction approach to improve stability of teleoperation systems over the Internet. Motion and force data flows in a teleoperation system are formulated in discrete time state-space models predicted by Bayesian filters, including the Kalman filter and particle filter. The particle filter, which is known as a robust tracking method in nonlinear and non-Gaussian environments, is used to compensate for the time-varying Internet delay. A stochastic analysis is presented to show stability improvement of a teleoperation system in the case when convergence of a Bayesian predictor is achieved and a generalized form of scattering transformation is used as a control scheme. Experiments are performed using a teleoperation system based on virtual reality. A haptic device is used as a human operator in conjunction with a mechanic-based virtual teleoperator by implementing the proposed Bayesian prediction method. Experimental results show that the proposed method improve stability of an overall teleoperation system in the presence of time-varying delay.

Popular usage of single endoscope and 2D viewing monitor in minimally invasive surgery (MIS) offer a natural requirement in developing a 3D interactive environment which can be integrated to assist the surgeons in an intuitive way. As such, development of the monocular-based image tracking of the surgical instruments becomes an essential step towards the development of such 3D surgical computer interface. In this paper, we study and analyze four possible methods for tracking instruments with a single endoscopic camera in an in-vitro setting. A 3D surgeon-computer interface is proposed as a future work which takes advantage of the above methods.

In this video we present a physics-based haptic simulation designed to teach basic suturing techniques for simple skin or soft tissue wound closure. The pre-wound suturing target, skin or deformable tissue, is modeled as a modified mass-spring system. The suturing material is designed as a mechanics-based deformable linear object. Tools involved in the live suturing procedures are also simulated. Collisions between the soft tissue and the needle, the soft tissue and the suture are analyzed. In addition to modeling the detail steps involved in a typical suturing procedure, modeling approaches for evaluation of a stitch are also discussed.

In this paper, an approach for intelligent integration of indoor visual tracking system for event detection and movement is proposed. This surveillance system is composed of a stationary camera and a pan tilt zoom (PTZ) camera, where the two cameras have been intrinsically and extrinsically calibrated. The stationary camera detects events such as fall and wandering using motion-based visual tracking. In this initial study, the PTZ camera tracks and follows the person who triggered the event using intelligent color-based particle filtering which is defined based on the expected dynamics of the scene. The purpose of tracking in view of the PTZ camera is to continuously keep the person in the full view of the camera which can further be processed for identifying details of the person. Preliminary experimental results for camera calibration, event detection, and human tracking are presented to demonstrate the performance of the proposed cooperative hybrid visual tracking system.

In this paper, we use an enhanced surface mesh model to simulate virtual dissection by progressive subdivision and re-meshing. Enhanced novel algorithms to generate interior structures that show the result of a cut that is generated by the interaction between instrument and model is used as the underlining framework. The notion of a cross cutting is introduced and solved to offer a more realistic interactive environment for various virtual diagnostic and dissection tasks. Our simulator supports two types of cutting: "cut-into", an instrument penetrating simulated tissues, and "cut through", an instrument cutting through tissues. In either case, a groove is developed in the path where the cutting has taken place to reflect the depth of the cut. Generation of a groove introduces a challenging problem when two cuts cross in their paths. For example, when two cutting path intersects (i.e., an occurrence of cross cutting), the current structures involved in the proximity of the cuts do not simulate a realistic intersecting cross cut. Although many studies have represented solutions to surface mesh cutting, a solution to an interactive cross cutting has not been adequately addressed yet. This paper presents an algorithm that can be flexibly applied for the simulation of an interactive cross cutting on a surface-mesh. Such solution can be further applied to many applications involving surface mesh.

Suturing simulations, of which real-time knotting and unknotting are the most challenge parts, are essential to today's surgical training systems. In this paper, we present a physics-based approach to real-time simulation of deformable linear objects (DLOs) with visual and force feedback. In our suture model, which can represent the mechanical properties of a real thread such as stretching, compressing, bending, and twisting, we simulate not only external forces, but also internal forces including the friction force during knotting and unknotting. We also present how forces propagate along the suture when the user pulls it with one or two hands. We developed a simulator to allow users to grasp and smoothly manipulate a virtual thread, and to tie an arbitrary knot.

In this paper we present a novel data structure combined with geometrically efficient techniques to simulate a "tissue peeling" method for deformable bodies. This is done to preserve the basic shape of a body in conjunction with soft-tissue deformation of multiple deformable bodies in a geometry-based model. We demonstrate our approach through haptic rendering of a virtual anatomical model for a dissection simulator that consists of surface skin along with multiple internal organs. The simulator uses multimodal cues in the form of haptic feedback to provide guidance and performance feedback to the user. The realism of the simulation is enhanced by computation of interaction forces using extrapolation techniques to send these forces back to the user via a haptic device.

Today's laparoscopic surgeon performs laparoscopic surgery by inserting two or three long tools into the patient's abdominal. Surgeon relies on the image captured by a laparoscope that is also inserted into the patient's abdominal. It is common to have a surgical assistant holding the laparoscope and taking directions from the main surgeon on how to move it to keep the surgical tools within the view. However, timely, accurate, and stable adjustments of the laparoscope cannot be guaranteed in lengthy operations due to fatigue of human assistant. We proposed a novel new design by replacing the human assistant with a spherical wrist mechanism robot. In addition, for developing a fully surgeon-based automatic integrated system, an automatic tracking and gesture recognizing sub-system is developed. The automatic tracking sub-system tracks the tip of a surgical tool and moves the laparoscope holding robot to keep the tool within the camera view. This paper focuses on the gesture recognizing sub-system that helps surgeon retrieve critical medical records of the patient instantly by recognizing surgical tool gestures. A modified background reduction method and neural network are applied in the tool gesture recognition process

This paper explores a cooperative manipulation method for orienting and translating convex objects in the plane. The manipulation task is performed by two agents using the concept of "virtual fence". During the manipulation, each agent makes a point contact with the object, and two agents push together along a straight-line. One advantage of a virtual fence over physical fence is that virtual fence can manipulate non-polygonal parts, and reduce the position and orientation uncertainties simultaneously. Moreover, the coordination between agents increases the flexibility of the manipulation system. We first identify two manipulation primitives, equilibrium and non-equilibrium pushes, and characterize the motion of the object under these two pushing actions. Then, we study the planning problem in the framework of switched system, and develop a fully analytical solution to the planning problem. Finally, manipulation examples and experiments are provided to demonstrate the proposed manipulation method

Motion planning of multiple mobile agents in virtual environments is a very challenging problem, especially if one wants to plan the motions of these agents in real-time. We propose a two layered approach to plan motions of multiple mobile agents in real-time. The mobile agents are moving in a 2-dimensional static environment with open spaces connected to each other by narrow corridors. The global path of each agent is computed by a decoupled planner during the preprocessing process with minimum delay. Each agent’s local path is generated in real-time by combining steering behaviors and a new, principled and efficient AI technique for decision making and planning cooperative multi-agent dynamic systems, Coordination Graph (CG). With CG, we can not only avoid deadlocks in narrow corridors, but also achieve more complicated behavior such as leader-and-followers behavior. We show, via some preliminary examples, real-time performance of our approach, for instance, several robots avoiding deadlocks and successfully navigating a corridor.

In this paper, neural networks are trained to compute the forward kinematics of spherical parallel manipulator (PM) for laparoscopic surgery application. Instead of solving a set of nonlinear equations for the forward kinematics, neural networks are used to map the input angles of revolute joints to the orientation of the manipulator. The training data are obtained from inverse kinematic relationships and measured from the experimental prototype model of the manipulator. Levenberg-Marquardt algorithm is used to train the neural networks, which leads to the fast convergence of the networks. The trained neural network model of forward kinematics are used in the real time interface between the graphical model and a haptic device for the laparoscopes surgery training application. Simulation and experiments are carried out to verify the performance of the proposed method.

This paper explores the unconstrained dynamic manipulation for parts on a plane using a one joint manipulator. The goal of dynamic manipulation is to pose an object from an initial to a desired goal configuration on a frictional supporting surface. The overall manipulation process is decomposed into two conjunct phases, namely, acceleration of the object and free sliding of the object. We study the acceleration of an object with a one joint manipulator, and develop a planning method by solving a free boundary value problem in this paper. Experimental results are presented to demonstrate the proposed manipulation approach.

This paper presents an initial study of an approach to reduce computational overhead in haptic rendering of physically based models. Haptic rendering refers to the notion of adding physical properties and behavior, specifically a sense of touch or force feedback, to models of objects. In this way, a user through a haptic feedback device can feel interaction forces while visually observing the objects. Physically based modeling is particularly important when representing deformable objects. In this paper, an approach based on a mass-spring damper system is used in modeling deformable objects. Deformation due to interaction forces is obtained by solving a set of differential equations, a process that is in general computationally demanding. To reduce this demand, the notion of level-of-detail in haptic rendering is introduced. Here the interplay between the graphical mesh and the haptic mesh as a function of various levels of subdivision is studied. The approach we describe is to adjust model parameters such that the user feels the same reaction force for a given deformation, regardless of the level of local subdivision.A preliminary user study with simple objects suggests there can be a local subdivision threshold such that the user cannot distinguish between global subdivision and the local subdivision introduced by the level-of-detail algorithm. This conclusion is beneficial for haptic rendering of deformable objects. Similar conclusions were obtained for haptic rendering of rigid objects. These results can be used as a guideline for other approaches to modeling deformable objects, such as finite element representations.

Tissue dissection is an important procedure in surgical simulation systems. Dissection involves cutting through and separating the tissue after a cut. In this paper, we use a surface mass-spring model to simulate virtual dissection by progressive subdivision and re-meshing. We introduce novel algorithms to generate interior structures that show the cutting result generated by the interaction between instrument and model. In addition, a novel data structure for object representation after the cutting action is proposed which allows the original soft object to be divided and a portion manipulated away. The dissection environment can support a number of user interface devices which can manipulate different representation of virtual instruments. These techniques are being integrated into a training environment for both open and minimally invasive surgery.

This demonstration presents the current state of an on-going team project at Simon Fraser University in developing a virtual environment for helping to train surgeons in performing laparoscopic surgery. In collaboration with surgeons, an initial set of training procedures has been developed. Our goal has been to develop procedures in each of several general categories, such as basic hand-eye coordination, single-handed and bi-manual approaches and dexterous manipulation. The environment is based on an effective data structure that offers fast graphics and physically based modeling of both rigid and deformable objects. In addition, the environment supports both 3D and 5D input devices and devices generating haptic feedback. The demonstration allows users to interact with a scene using a haptic device.

In this paper, a novel numerical approach is proposed to solve the initial velocities of the free sliding object for given initial and final configurations. To find the desired initial velocities for free sliding objects is a key step for implementing dynamic manipulation. In order to plan the initial velocities, the motion of free sliding objects is modeled as a set of 6 first order differential equations, and the planning problem is formulated as a free boundary value problem (FBVP). Through a simple transformation, the FBVP is reduced to a standard Two-point boundary value (TPBV) problem. Quasi-Newton based optimization procedures are utilized to solve the planning problem. Unlike existing approaches, the proposed method does not require qualitative motion characteristics, thus it can be used for objects with general shape and arbitrary pressure distribution. Simulation results on polygonal objects with three to five vertices are used to demonstrate the planning method.

This paper proposes a novel planning method for multi-agent dynamic manipulation on a plane. The objective of planning is to find optimal forces exerted on the object by agents with which the object can follow a given trajectory. The main contributions of the proposed approach is: First, through integrating of noncooperative game and neural-net approximation, the planner can deal with unknown pressure distribution effectively. Second, by introducing cooperative game between agents, the forces exerted by agents distributed optimally. Based on the dynamic model of the pushed object, the planing problem is solved in two levels hierarchically. In the lower control level, generalized force inputs are designed by using minimax technique to achieve the tracking performance. In the coordination level, cooperative game is formulated between agents to distribute the generalized force, and the objective of the game is to minimize the worst case interaction force between agents and object. Simulations are carried out for the three-agent cooperative manipulation, results demonstrate the effectiveness of the proposed planning method.

This paper addresses the planning problem for multiagent dynamic manipulation in the plane. The objective of planning is to design the forces exerted on the object by agents with which the object can follow a given trajectory in spite of the uncertainty on pressure distribution. The main novelty of the proposed approach is the integration of noncooperative and cooperative games between agents in an hierarchical manner. Based on a dynamic model of the pushed object, the coordination problem is solved in two levels. In the lower control level, a fictitious force controller is designed by using a minimax technique to achieve the tracking performance. The design procedure is divided into two steps. First, a linear nominal controller is designed via full-state linearization with desired eigenvalues assignment. Next, a minimax control scheme is specified to optimally attenuate the worst-case effect of the uncertainty due to pressure distribution and achieve a minimax tracking performance. In the coordination level, a cooperative game is formulated between agents to distribute the fictitious force, and the objective of the game is to minimize the worst-case interaction force between agents and the object. Simulations are carried out for two-agent and three-agent manipulations, results demonstrate the effectiveness of the planning method.

Based on the notion of wave variables and the idea of wave-integral transmission, a new method is suggested to match the system parameters with changes in the delay. An autoregressive model is used as a predictor to forecast the future values of the delay. The predictions are used with a lookup table to tune the gain with which the wave integrals are to be fed to the system. This gain scheduling and tuning improves the system performance and decreases the mismatch between forces and velocities at the master and slave sides.

This work studies a new stratified motion planning algorithm. The proposed technique is able to lead a stratified system along a restricted class of reference trajectories while the earlier approach aimed only to reach a final state without influencing the trajectory. The suitable class of reference trajectories is still restricted because they should go through a sequence of connected integral submanifolds. A highly oscillatory sequence (HOS) of inputs is built in the method to produce a sequence of trajectories converging to the reference trajectory. The major benefit of the new concept in comparison with the conventional approach emerges when obstacle avoidance is required in the configuration space. The method is demonstrated on a simple model of a hexapod robot.

In the past few years, the application of image tracking in laparoscopic surgery has gained popularity. In such an approach, the robot controls the movement of the laparoscope (endoscope) in surgery by following the feedback of the image tracking information. The calibration of the distorted endoscopic images is an important first step toward realizing such an approach. However, there exist very few methods for such calibration. In the paper, a new method of calibration and measurement of the endoscopic images is proposed. The high distortion of the endoscopic images makes the calibration difficult. Endoscopic images have typical barrel distortion. That is, the distortion increases as the observation becomes more and more eccentric. We propose an idea that only concentrates on the center area of the image. Within this area, we can ignore the complex and time-consuming distortion-correction step. A simple method for finding the intrinsic calibration parameters is then proposed. Design of a marker for the tracking task is also described. Some experimental results are presented to show the feasibility of the proposed method.

Currently available laparoscopic graspers have a teeth-like surface without any sensors built on them. Thus the surgeon loses the tactile feedback required to manipulate tissues safely. The paper reports on the design, fabrication and testing of a micromachined piezoelectric tactile sensor which can measure the combined magnitude and position of the applied force on the sensor without changing the design of the the present day laparoscopic grasper. It consists of a teeth-like upper silicon layer, a patterned polyvinylidene fluoride (PVDF) film and an elastic substrate. The sensor exhibits good linearity, wide bandwidth, high force sensitivity and negligible noise to signal ratio. The theoretical analyses of various applied loads on the sensor are made and compared with experimental values. The advantages and limitations of the sensor are also discussed. It is shown that the sensor is integrated into a prototype laparoscopic grasper.

Addresses the kinematic modelling, solutions and trajectory planning of a tele-laparoscopic manipulator. This type of manipulator can be used in remote positioning of laparoscopic tools through a tele-operating system. Specifically the paper models kinematics of a typical manipulating system which can be used in such tele-surgery. Inverse kinematics solutions are also obtained for two kinematically constrained motions which are part of a typical trajectory of the laparoscopic tools. These are fixed axis rotation of the tool and its straight line motion. Simulation results are presented to demonstrate the validity of such models and solutions.

This paper examines sensor-based orientation of polygonal shaped objects using a 6-axis force/torque sensor which is used to supply rotation and force information during the orientation process. Sensor-based algorithms utilizing rotation sense and force information are presented which offer improvements over the best sensorless orienting techniques, and are shown to be better than previous sensor-based techniques for parts with the same diameter value for every stable edge. Plans generated by our algorithm were tested and verified using a unique conveyor/robotic car testbed.

In endosurgery, tissue manipulation is performed by long graspers which have poor force-reflection property, i.e. they do not reflect the grasping force to the hand of the surgeon. In the paper, a novel design of an electromechanical system is considered which can enhance the force-reflecting capability of endosurgical graspers. The type synthesis of such a haptic interface leads to the application of a tunable spring. The design of the tunable spring is optimized based on the haptic and surgical requirements. Moreover, by using suitable control laws, it is shown that the primary requirements of the design application can be met. Simulation and experimental results are presented using a prototype model of such a haptic interface to demonstrate the practicality of such a design concept.

This paper examines a sensor based technique for determining the orientation of a polygon on a horizontal surface by pushing with a force/torque sensor equipped fence. Using an exploratory process, the resulting algorithm can determine the orientation, to symmetry, of the sub-class of polygons that are stable on all edges, in at most two pushes.

This paper defines a novel approach in application of part orienting on conveyer belt utilizing active fence (AF) with embedded sensory system. The application system requirements and limitation are presented and a novel stateless orienting algorithm is developed. The algorithm incorporates the part-AF frictional aspects, part motion behavior (rolling) while being pushed by AF and uncertainties in the system. The controller of AF incorporating the sensor information was developed and experimental result is given. Furthermore, an initial algorithm for orienting randomly oriented parts using an AF is proposed for orienting a simple object.

Present day endoscopic graspers do not have any sensors built in them. Thus the surgeon cannot estimate the amount of pressure being applied to manipulate the tissue safely. The paper reports on the design, fabrication and results of a silicon micromachined piezoelectric tactile sensor which can be integrated on to the tip of the endoscopic grasper. The sensor has a rigid tooth-like surface similar to the present day endoscopic grasper. It consists of upper silicon, a perspex substrate and a patterned polyvinylidene fluoride(PVDF) film, which is sandwiched between the two layer. It is shown that the magnitude and the position of the applied force on the sensor can be found from the magnitude of the output signals from the PVDF sensing elements and the slope of the signal at the position of the application of the force respectively. The sensor exhibits high force sensitivity, large dynamic range and good linearity. The theoretical analysis of the sensor is made and compared with the experimental values. The advantages and limitations of the sensor are also reported. Since the sensor simulates the teeth-like surface of the existing endoscopic grasper, it is possible to integrate the device on to the grasper of the endoscopic surgical instrument.

This paper re-examines a part orienting technique that orients polygonal shaped parts with a series of fences suspended above a conveyor belt. We examine the effect of uncertainty in the coefficient of friction as well as the typical size of the final assembly. The search technique in the original work although resolution complete, was inefficient, so we offer a heuristic search method that offers good performance. Several fence sequences generated by our algorithm were tested on real polygonal objects.

Fixtures are devices used in manufacturing to immobilize and localize a part while the processing operations are being performed. This paper explores an application of a novel fixturing tool. The fixturing tool proves to deliver a force closure independently of the clamped part configuration. Furthermore, an integrated sensory system is developed in order to determine the actual clamped part configuration, and a systematic method for determining the clamped part configuration from the acquired sensory data is investigated.

We propose an approach for investigating the shape properties of objects with curved surfaces using tactile sensing by a dexterous robot hand. Our proposed exploratory procedure (EP) uses multiple fingers to slide along a surface while sensing contact points and surface normals. Our approach incorporates the surface normal information into a B-spline surface fit of the data gathered from this EP. This additional surface normal information was found to improve the approximation of the surface. The shape properties of this B-spline surface are analyzed to recognize the shape of the object. A confidence estimate of the estimated shape is also calculated.

The positioning stand could help the surgeon to position and lock endoscopic tools without the need for an assistant surgeon. The kinematic configuration of the positioning stand comprises two main parts, the arm (for positioning) and the wrist (for orienting the tool). The main requirement of the wrist is to perform spherical movements around the incision point. A concentric multi-link spherical joint design has been developed for the wrist mechanism. The size synthesis is performed to minimize the overall size of wrist and also to maximize its range of angular movements. The type synthesis of the positioning arm has led to SCARA configuration, as a balanced and easy to move arm configuration. The size synthesis of the arm is carried out with the goal of minimizing its overall dimensions, based on reachable workspace and manipulability of the arm. The integration of the wrist and arm is performed by optimizing the orientation of wrist in such a way that the interference between the wrist and the workspace of surgeon is minimized.

We present a design of end-effector that is flexible enough to be able to manipulate a variety of objects in assembly tasks. Modularity and reconfigurability will be a unifying trait of this design. As a result, the grasp stability is improved and the total grasp force is reduced by adding the extra side contact constraints. At the same time we present a complete grasp planning algorithm for the end-effector. The grasp planning algorithm, based on a generate and test paradigm, enumerates grasp configurations. Candidate grasp configurations are generated using heuristics. The test phase involves checking each simultaneous contact configuration for force closure. The resulting grasp configurations are then examined for stability.

Manipulation of objects by multiple agents, such as fingers of dexterous mechanical hand, is considered in this paper. In particular, the type of manipulation where the object slides between the fingers in a predefined direction. It is assumed that the sliding motion of the object is due to the external forces acting on the object. These forces can be the controlled interaction of the object and the environment or the force acting by another contacting agent. The proposed method takes advantage of the duality between the force (wrench) and velocity (twist) to determine the direction of slip velocity and magnitude of the friction force required to have local slip at the contact point(s). The method presents novel utilization of tools from screw geometry and linear algebra to determine the location of the desired slip at contact points and the magnitude of the friction forces for allowing the local slippage.

Manipulation of objects by multiple agents such as fingers of dexterous mechanical hand is considered in this paper. In particular, the type of manipulation where the object slides between the fingers in a predefined direction. It is assumed that the sliding motion of the object is due to the external forces acting on the object. These forces can be the controlled interaction of the object and the environment or the force acting by another contacting agent. The proposed method takes advantage of the duality between the force (wrench) and velocity (twist) to determine the direction of slip velocity and magnitude of the friction force required to have local slip at the contact point(s). The method presents novel utilization of tools from screw geometry and linear algebra to determine the location of the desired slip at contact points and the magnitude of the friction forces for allowing the local slippage.

This paper presents a novel approach for orienting an object on conveyer belt utilizing an active fence (AF). The AF was implemented with low cost sensory system used for tracking the collision/contact force generated from interaction between the AF and the object. A generalized mechanical model of the collision/contact event is developed and basic relations between impact signature and object properties are established. Also is given a qualitative analysis of the object motion behavior and defined the events of interaction between the object and the AF.

Proposes an approach-"Blind Man's" approach-to shape description in which tactile information is sensed from the fingertips of a dexterous hand. Using this contact information, we investigate two complementary methods for curvature estimation. The first method is based on rolling one finger to estimate curvature at a point on the surface. We use Montana's equations for estimating curvature at a point using simulations and analyze the sensitivity of the approach to noise. The second method uses multiple fingers to slide along a surface while sensing contact points and surface normals. We present a method to extract the shape properties of a patch obtained by fitting a B-spline surface to this multi-fingered sweep across the surface of the object. The method enables us to extract higher level shape information based on the curvature properties of patch.

A formal approach is used to postulate a model of a manipulator in contact with a rigid environment, and a control problem encountered in robotic contact tasks is defined. The model is obtained using elementary causal representation of mechanical elements; springs and dampers are connected between the end-point of the manipulator and the rigid environment. The control problem is stated as the stable control of velocities and contacting forces of the end-point of the manipulator, and a solution approach is discussed.>

In most applications of manipulating systems, the manipulator has to make contact with rigid fixtures in its environment. In practice, it has been noticed that the performance of the contact force controllers is affected when the manipulator is in contact with a rigid environment or in the presence of uncertainties. A model of the manipulator in contact with a rigid environment is presented, and a robust control architecture based on a general theory of a servomechanism for controlling the contact force is proposed. The results of this work are demonstrated experimentally using a two-degree-of-freedom direct drive robot.>

A method for interpreting the measured contact forces during compliant robot motions using kinematic screws is presented. Domain-specific rules combined with partial a priori knowledge of mating parts geometry and interpreted force signals are used to reason and make inferences about the initial contact configuration. The likely contact surfaces are predicted and point(s) or line(s) of contact are fully defined. These surfaces are idealized and represented by quadratic equations or polyhedral surfaces. The geometric properties of surfaces at the contact location are used to select the contact configuration when multiple solutions exist. The developed methodology has been validated experimentally using a 6R manipulator, six-axis force sensor, and host computer.>