Emilio Jesús Lázaro Sánchez

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.

A review of surgical robots for spinal interventions.

This study aimed to describe the state of the art in surgical robotics for spinal interventions, a challenging problem for which robots can provide valuable assistance.

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.

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.

Training of Procedural Tasks Through the Use of Virtual Reality and Direct Aids

A high percentage of the human activities are based on procedural tasks, for example cooking a cake, driving a car, fixing a machine, etc. Reading an instruction book, watching a video or listening the explanation from an expert have been the traditional methods to learn procedural tasks. But, most researchers agree that procedural tasks are learnt gradually as a result of practice through repeating exposures to the task.

Influence of User Grasping Position on Haptic Rendering

This paper investigates the effect of user grasping position on the performance of haptic rendering. Two dynamic models, with seven and eleven parameters, respectively, have been used to characterize the PHANToM haptic interface and the user. The parameter variability analysis shows that user grasping position significantly affects system dynamics. This variation also influences the phase margin of the system, leading to different damping factors in response to contacts with rigid virtual objects. To compensate this effect, an adaptive haptic rendering has been developed and successfully implemented, imposing a similar damping factor in the transient responses for all grip positions.

Optimal Cost Haptic Devices for Driving Simulators

Driving simulators reproduce actual driving conditions. The main purpose of these systems is to teach trainees how to drive under safe and controlled conditions. In order to have realistic training sessions, simulator manufacturers tend to use controls found in the actual vehicle under simulation. This paper presents two haptic devices that use force control to accurately reproduce the behaviour of a lever and gear shift. The presented devices are advantageous in their compact and versatile design, reaching an optimal balance between low cost and high performance. The devices have been tested by real drivers, and implemented in commercialized train, and bus/truck driving simulators.

Training strategies for learning a 3D trajectory with accuracy

The goal of this study was to evaluate different learning conditions for motor skill transfer. The study was divided into two experiments with the same task: learning a 3D trajectory with accuracy. The first experiment was focused on evaluating the efficiency of three feedback schemes for the target trajectory: visual, haptic and visual-haptic feedback. The second experiment was focused on analyzing the influence of decreasing the feedback during the training process. The results suggest that the best learning condition for learning a 3D trajectory with accuracy is to provide visual-haptic feedback, which facilitates the understanding of the dimension and orientation of each trajectory segment and solves any visual discrepancies that may exist. Furthermore, although continuous feedback can create dependences in users and impede the transfer of motor skills, feedback based on user request can also be dangerous since users can create a wrong mental representation that keep them from replicating the trajectory accurately. Therefore, when the performance of a task depends on references created during the training process, it seems appropriate for the system to provide automatic feedback based on user performance.

Real-Time Visual Tracking of Deformable Objects in Robot-Assisted Surgery

One of the most challenging problems in robot-assisted surgical systems is to provide surgical realism at interactive simulation rates. The proposed visual tracking system can track and register object deformations in real time using a physically based formulation, despite the occlusions produced by the robotic system itself. The results obtained provide an accurate visual representation of the deformed solid and will thus enable new assistance approaches to help surgeons during surgical procedures.

Learning Force Patterns With a Multimodal System Using Contextual Cues

Abstract Previous studies on learning force patterns (fine motor skills) have focused on providing “punctual information”, which means users only receive information about their performance at the current time step. This work proposes a new approach based on “contextual information”, in which users receive information not only about the current time step, but also about the past (how the target force has changed over time) and the future (how the target force will change). A test was run to compare the performance of the contextual approach in relation to the punctual information, in which each participant had to memorize and then reproduce a pattern of force after training with a multimodal system. The findings suggest that the contextual approach is a useful strategy for force pattern learning. The advantage of the contextual information approach over the punctual information approach is that users receive information about the evolution of their performance (helping to correct the errors), and they also receive information about the next forces to be exerted (providing them with a better understanding of the target force profile). Finally, the contextual approach could be implemented in medical training platforms or surgical robots to extend the capabilities of these systems.