Iñaki Díaz

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.

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.

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.

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.

Influence of multisensory feedback on haptic accessibility tasks

Environments of a certain nature, such as those related to maintenance tasks can benefited from haptic stimuli by performing accessibility simulation in a realistic manner. Accessibility is defined as the physical feasibility of accessing an element of a 3D model avoiding undesirable collisions. This paper studies the benefits that multisensory systems can provide in performing this kind of tasks. The research is specially focused on the improvements provided by auditory feedback to the user’s performance. We have carried out a user study where participants had to perform an accessibility task with the aid of different combinations of sensorial stimuli. A large haptic interface for aeronautic maintainability has been extended with real-time sound generation capabilities to study this issue. The results of these experiments show that auditory stimuli provide with useful cues to the users helping them to correct trajectories and hence improving their performance.

Stable Discrete-Time Impedances for Haptic Systems With Vibration Modes and Delay

The stability of haptic rendering is affected by many factors that limit the range of impedances that can be applied to virtual objects. This paper addresses the effect of the vibration modes of the haptic interface on the stability of the impedance control loop. It is well known that experimental stability boundaries present complex shapes, making it difficult to predict the final Z-width of the haptic system. This paper shows how the vibration modes of the mechanical interface highly affect the size of the Z-width, causing a sudden reduction in the critical virtual stiffness K if the virtual damping B is increased beyond a certain value. The inclusion of the most significant vibration modes in the theoretical model of the haptic system-together with the viscous damping, time delay and sampling rate-makes it possible to obtain the stable impedances associated with the haptic device. A PHANToM Premium 1.0 haptic interface was used as a test bed to validate this paper. Although results have been tested only on this device, this paper proposes a methodology for obtaining the Z-width that can be generalized for any other haptic system.

A Haptic Interface for Automobile Gearshift Design and Benchmark

Design, ergonomics and haptic feedback are features critical to the development of an eye-catching automobile gearshift. Manufacturers have to design and test a large number of prototypes, with different transmissions, dynamics, etc., before an appealing and marketable solution can be found. This paper introduces a haptic interface for automobile gearshift design and benchmark. It allows automobile gearshift developers to test new models quickly and change most critical design features on the fly in order to find the best possible solution. As a result, traditional trial-and-error methods can be avoided, significantly reducing design costs and time. The system is also a powerful test-bed to perform large-scale studies to analyse key selling features and preferences among customers.

Using an admittance algorithm for bone drilling procedures

Bone drilling is a common procedure in many types of surgeries, including orthopedic, neurological and otologic surgeries. Several technologies and control algorithms have been developed to help the surgeon automatically stop the drill before it goes through the boundary of the tissue being drilled. However, most of them rely on thrust force and cutting torque to detect bone layer transitions which has many drawbacks that affect the reliability of the process. This paper describes in detail a bone-drilling algorithm based only on the position control of the drill bit that overcomes such problems and presents additional advantages. The implication of each component of the algorithm in the drilling procedure is analyzed and the efficacy of the algorithm is experimentally validated with two types of bones.

Development of a robotic device for post-stroke home tele-rehabilitation:

This work deals with the complex mechanical design task of converting a large pneumatic rehabilitation robot into an electric and compact system for in-home post-stroke therapies without losing performance. It presents the new HomeRehab robot that supports rehabilitation therapies in three dimensions with an adaptive controller that optimizes patient recovery. A preliminary usability test is also conducted to show that its performance resembles that found in RoboTherapist 2D commercial system designed for hospitals. The mechanical design of a novel and smart two-dimensional force sensor at the end-effector is also described.

Prick test: evolution towards automated reading.

The prick test is one of the most common medical methods for diagnosing allergies, and it has been carried out in a similar and laborious manner over many decades. In an attempt to standardize the reading of the test, many researchers have tried to automate the process of measuring the allergic reactions found by developing systems and algorithms based on multiple technologies. This work reviews the techniques for automatic wheal measurement with the aim of pointing out their advantages and disadvantages and the progress in the field. Furthermore, it provides a classification scheme for the different technologies applied. The works discussed herein provide evidence that significant challenges still exist for the development of an automatic wheal measurement system that not only helps allergists in their medical practice but also allows for the standardization of the reading and data exchange. As such, the aim of the work was to serve as guideline for the development of a proper and feasible system.