Jorge Juan Gil

Lower-Limb Robotic Rehabilitation: Literature Review and Challenges

This paper presents a survey of existing robotic systems for lower-limb rehabilitation. It is a general assumption that robotics will play an important role in therapy activities within rehabilitation treatment. In the last decade, the interest in the field has grown exponentially mainly due to the initial success of the early systems and the growing demand caused by increasing numbers of stroke patients and their associate rehabilitation costs. As a result, robot therapy systems have been developed worldwide for training of both the upper and lower extremities. This work reviews all current robotic systems to date for lower-limb rehabilitation, as well as main clinical tests performed with them, with the aim of showing a clear starting point in the field. It also remarks some challenges that current systems still have to meet in order to obtain a broad clinical and market acceptance.

Stability analysis of a 1 DOF haptic interface using the Routh-Hurwitz criterion

A haptic interface is a kinesthetic link between a human operator and a virtual environment. A way of studying the stability of a 1 degree-of-freedom (DOF) haptic interface using the Routh-Hurwitz criterion is presented in this brief. Parameter conditions that guarantee the stability of the system with a static virtual environment have been found. These conditions can help in the development and implementation of haptic devices. Finally, they have been confirmed by experimental results.

A large haptic device for aircraft engine maintainability

The virtual reality for maintainability (Revima) VR system supports maintainability simulation in aeronautics. Within this project we have developed and integrated a haptic device, the large haptic interface for aeronautic maintainability (LHIfAM). We use this device to track hand movements and provide force feedback within the large geometric models that describe aircraft engines. The user movements are the same as those that occur when testing physical mock-ups. An integrated haptic device and VR system for testing aircraft engines reduces development costs and avoids the necessity of physical mock-ups formaintainability.

Description of a haptic system for virtual maintainability in aeronautics

This paper describes a haptic system for maintainability simulation in aeronautics, called REVIMA (Virtual Reality for Maintainability). In this project a software-hardware tool is designed and built to realistically simulate assembly-disassembly operations. It also helps to perform accessibility, interference and maintainability analysis by using virtual reality techniques without physical mock-ups. The system gives the user a reliable and realistic response. In order to achieve these requirements, the device has a workspace similar to the size of a turbo-engine. In addition this workspace can be placed in different positions to study ergonomics aspects of the simulated tasks.

Influence of Vibration Modes and Human Operator on the Stability of Haptic Rendering

Developing stable controllers, which are able to display virtual objects with high stiffness, is a persistent challenge in the field of haptics. This paper addresses the effect of internal vibration modes and the human operator on the maximum achievable virtual stiffness. An 11-parameter mechanical model is used to adequately characterize the overall system dynamics. Experiments that are carried out on LHIfAM and PHANToM haptic interfaces demonstrate the importance of vibration modes to determine the critical stiffness when the user grasps the device.

Decreasing the Apparent Inertia of an Impedance Haptic Device by Using Force Feedforward

When using a haptic device in unconstrained movement, the user should experience only minor inertia. For certain tasks, the workspace of the device should be similar or even larger than that of the human arm. This condition tends to lead to large devices that often present high rather than low inertia. This brief describes a method to decrease the inertia felt by users of impedance haptic devices. It has been successfully implemented in the LHIfAM haptic device. The effect that this strategy has on stability and virtual contact is also illustrated.

Stability Boundary for Haptic Rendering: Influence of Damping and Delay

The influence of viscous damping and delay on the stability of haptic systems is studied in this paper. The stability boundaries have been found by means of different approaches. Although the shape of these stability boundaries is quite complex, a new linear condition which summarizes the relation between virtual stiffness, viscous damping and delay is proposed. This condition is independent of the mass of the haptic device. The theoretical results are supported by simulations and experimental data using the DLR light-weight robot.

Bone drilling methodology and tool based on position measurements

Bone drilling, despite being a very common procedure in hospitals around the world, becomes very challenging when performed close to organs such as the cochlea or when depth control is critical for avoiding damage to surrounding tissue. To date, several mechatronic prototypes have been proposed to assist surgeons by automatically detecting bone layer transitions and breakthroughs. However, none of them is currently accurate enough to be part of the surgeons standard equipment. The present paper shows a test bench specially designed to evaluate prior methodologies and analyze their drawbacks. Afterward, a new layer detection methodology with improved performance is described and tested. Finally, the prototype of a portable mechatronic bone drill that takes advantage of the proposed detection algorithm is presented.

On the Z-width limitation due to the vibration modes of haptic interfaces

This paper addresses the effect of internal vibration modes on the stability boundary for haptic rendering. A linear model that includes two vibration modes has been used to characterize one degree-of-freedom of the PHANToM 1.0 haptic interface, and predict the maximum achievable impedances for haptic rendering. The theoretical and experimental results show that the vibration modes of the mechanical interface significantly limit the Z-width of the haptic system.

A haptic pedal for surgery assistance

The research and development of mechatronic aids for surgery is a persistent challenge in the field of robotic surgery. This paper presents a new haptic pedal conceived to assist surgeons in the operating room by transmitting real-time surgical information through the foot. An effective human-robot interaction system for medical practice must exchange appropriate information with the operator as quickly and accurately as possible. Moreover, information must flow through the appropriate sensory modalities for a natural and simple interaction. However, users of current robotic systems might experience cognitive overload and be increasingly overwhelmed by data streams from multiple modalities. A new haptic channel is thus explored to complement and improve existing systems. A preliminary set of experiments has been carried out to evaluate the performance of the proposed system in a virtual surgical drilling task. The results of the experiments show the effectiveness of the haptic pedal in providing surgical information through the foot.