Omar A. Dominguez-Ramirez

Haptic cues for effective learning in 3D maze navigation

Navigation in 3D virtual environment is a popular task in modern 3D applications. The main information is visual, which leads to an incomplete acknowledgement of the virtual environment, since other senses are impaired, such as touch or hearing. Haptic devices provides kinesthetic information which may improve the navigation capabilities of humans in virtual environments, however 3D haptic applications use intensive low level programming languages. This paper presents a 3D maze haptic navigation based on kinesthetic perception of the walls of the maze, wherein the walls surface have different properties, thus a learning haptic process enables better navigation skills after few trials. Experimental results done with a test users group, is realized with Novint as the haptic device and Panda3D as the haptic rendering system. Results with and without haptic cues indicates a successful learning curve to navigate with haptic cues. The haptic cues used are surface texture, viscosity, elasticity, shape recognition and external force. The results highlight the importance of haptic cues as navigation reference to improve the performance of the users.

Haptic Remote Guided Exploration of Deformable Objects

Perception and interaction with virtual objects through kinesthetic sensation and visual stimuli is the basic issue of a haptic interface. If a real object is located at a remote station and explored (in contact) with a passive device, a haptic interface in a local station can be used to perceive its spatial and surface attributes. This is one type of haptic guidance. This problem has been addressed with undeformable object, and contact force modelled with the penalty-based method. However, this approach yields limited haptic properties of the object, and if the object is deformable, it is difficult to achieve stable contact. However, there exists relevant tasks for exploration of deformable objects, such as exploration of fruits, skin of animals and dermatological procedures. Motivated by these kind of tasks, an approach for guided remote exploration of deformable objects is proposed in this paper. A real object is explored in a remote location and object attributes and properties such as spatial location, shape, texture and roughness are perceived with a constrained Lagrangian-based decentralized force-position controller in the local station. Stable interaction is theoretical proved and experimental results using PHANToM 1.0A validate the approach.Copyright

Haptic training method for a therapy on upper limb

There are many research works on robotic devices to assist in movement training following neurologic injuries such as stroke with effects on upper limbs. Conventional neurorehabilitation appears to have little impact on spontaneous biological recovery, to this end robotic neurorehabilitation has the potential for a greater impact. Clinical evidence regarding the relative effectiveness of different types of robotic therapy controllers is limited, but there is initial evidence that some control strategies are more effective than others. This paper consider the contribution on a haptic training method based on kinesthetic guidance scheme with a non linear control law (proxy-based second order sliding mode control) with the human in the loop, and with purpose to guide a human users movement to move a tool (pen in this case) along a predetermined smooth trajectory with finite time tracking, the task is a real maze. The path planning can compensate for the inertial dynamics of changes in direction, minimizing the consumed energy and increasing the manipulability of the haptic device with the human in the loop. The Phantom haptic device is used as experimental platform, and the experimental results demonstrate the effectiveness of this application.

Texture, roughness, and shape haptic perception of deformable virtual objects with constrained Lagrangian formulation

Haptic interaction with a virtual object establishes a kinesthetic sensation to the user. It is well accepted that to better perceive a given virtual object, it is relevant to yield some surface properties of the object, for instance the shape through the normal contact force, the roughness by the sliding friction, and the texture as a combination of both of them. On this problem, force control is the key issue. This problem has been highlighted three decades ago, when there was not available any good haptic display. Since then, a number of methods on force feedback have been proposed to convey these features, wherein the main scheme is based on the penalty method. However, when the object is deformable, the penalty method cannot compute properly the shape and roughness since the contact force ignores the inherent deformation of the object. In contrast, if the contact force is computed using the constrained Lagrangian, this force depends on the dynamic deformation of the object. In this paper, a constrained Lagrangian-based oriented framework is proposed to compute the contact force dynamically, in such a way that it can easily realize these effects over implicit dynamical objects. This powerful scheme can produce these effects seamlessly. Experimental results using PHANTOM on deformable and undeformable virtual objects are presented and discussed.

Modular Platform for Haptic Guidance in Paediatric Rehabilitation of Upper Limb Neuromuscular Disabilities

In this paper, we present a haptic guidance platform to support physical rehabilitation of neuromuscular disabilities, providing a solution to the problem of the increasing demand of neuromuscular therapy in overcrowded facilities with deficit of rehabilitation professionals. The platform, characterized by a portable modular architecture, can be configured according to the treatment suggested by the physician, for instance, a Local Haptic Guidance configuration for patients requiring a continuous repetition of coordinated movements to recover, or improve, motor skills, and, a Remotely- Assisted Haptic Guidance for a direct intervention of the therapist, evaluating and stimulating, simultaneously, the neuromuscular condition of the patient. We also include some preliminary results when it is applied to treat two paediatric cases of congenital disease: Hemiparesis and Myelomeningocele.

Kinematic and Dynamic Modeling of the PHANToM Premium 1.0 Haptic Device: Experimental Validation

This article presents the experimental verification of kinematic and dynamic models of the PHANToM Premium 1.0 haptic device [2]. Dynamic properties are evaluated [7], in order to apply nonlinear control techniques and evaluation of manipulability and energy in real-time. Position kinematics and differential kinematics are validated for the trajectory planning by using joint control techniques for local haptic guidance and kinematics and dynamics operated control methods for virtual man-machine interaction (haptic interface).

Haptic Guidance Based on Sub-optimal Passivity Control

This article presents a strategy of haptic guidance for training based on a sub-optimal control law for path planning, designed from theory passive and applied to haptic devices modeling as manipulators robots with contact task, considering the human operator in the control loop. The experiments were developed with the PHANToM premium 1.0 haptic device and a closed path planning in its space of admissible configurations with presence of extern disturbances for proof experimental of robust.

Robust higher order sliding mode based impedance control for dual-user teleoperation under unknown constant time delay

This paper presents a dual-user teleoperation scheme to perform a collaborative task using n-DOF nonlinear manipulators as masters and slave. It consists on impedance controllers for the manipulators in order to achieve a desired dynamic behavior depending on the users necessities. Moreover, to cope with the uncertainty in the slave, a sliding mode controller is introduced and a desired impedance model for the salve is chosen as the sliding surface. Since the slave teleoperator is in contact with a rigid environment, the slave controller requires a free of chattering control strategy, which makes first order sliding mode teleoperation control unsuitable. Then a higher order sliding mode based impedance controller is proposed to guarantee robust impedance tracking under constant, but unknown time delay. Therefore, a position scaling factor is incorporated to deal with the different workspaces among masters and slave. The validity of the proposed control scheme is demonstrated via simulations performed on a 3-DOF dual-user teleoperation system. The simulation setup includes a Phantom Premium 1.0, a Phantom Omni, a Catalyst-5 and communication channels which suffer from constant unknown time delays.

Robotic Design of an Upper Limb Exoskeleton for Motion Analysis and Rehabilitation of Paediatric Neuromuscular Disorders

In this paper, we present a mechanical design, based on robotic paradigms, of an upper limb exoskeleton for motion analysis in diagnosis and as a passive device to correct abnormal movements in rehabilitation of children with neuromuscular disorders. Our proposal considers the exoskeleton as a full articulated anthropomorphic manipulator that reproduce the kinematic chain of the shoulder, arm, forearm and wrist. It is characterized by introducing a composed joint to reproduce the movements of the shoulder girdle according to a kinematic model obtained experimentally. Also, by offering an ergonomic support during exploration and rehabilitation to patients affected with postural defects. In the design we consider the use of sensor to electronically measure and register the main state variables describing the patient’s movements.

NASA-TLX Assessment of Modern Close Loop Controllers in Haptic Guidance for Assisted Rehabilitation

Haptic guidance in rehabilitation provides tactile and kinaesthetic stimuli on patients with neuromuscular disabilities. Effects of reactive guidance depend essentially on the quality of the close loop controller and on its implementation where its design is subjected to human-centred engineering criteria such as stability, efficiency, bandwidth and latency. However, the dynamic action of the closed loop system is not necessarily ergonomic, affecting the user’s perception of the guidance action and thus, the benefices in a therapy. In this paper, we assess, based on the NASA-TLX protocol, the workload perception of simple temporal-spacial tasks on a haptic guidance system when two different controllers of similar complexity are used: the popular regulator PD plus gravity compensation and a high performance tracking controller designed on a second order sliding mode paradigm. Results indicate that human-oriented assessment complies with and it is consistent to the advanced performance of the non-linear controller, becoming a viable alternative for haptic assisted rehabilitation.