Cristobal Ochoa-Luna

Force-position control of a robotic exoskeleton to provide upper extremity movement assistance

This paper presents an upper extremity (UE) wearable robot, ETS-MARSE and its control strategy to provide movement assistance and active rehabilitation exercises to physically disabled individuals having impaired UE function. The ETS-MARSE was designed to be worn on the lateral side of UE and is able to assist arm movements at the level of shoulder, elbow, forearm and wrist joint movements. Considering the dynamic modelling of the robot system and the UE motion which are non-linear in nature, a non-linear sliding mode control with exponential reaching law was used to manoeuvre the ETS-MARSE and to provide both passive and assisted arm movement therapy. To provide passive arm movement therapy, pre-programmed trajectories corresponding to recommended passive rehabilitation exercises were used to manoeuvre the ETS-MARSE, whereas in case of assisted rehabilitation therapy user interaction wrist force sensor signals were used to steer the ETS-MARSE in assisting the UE movements. Experiments involving healthy human subjects were performed with the developed ETS-MARSE to evaluate the controller’s performance and that of the ETS-MARSE in regards to providing the therapeutic exercises. Experimental results indicate that with the proposed control strategy, ETS-MARSE can effectively deliver rehabilitation exercises.

Cartesian trajectory tracking of an upper limb exoskeleton robot

To rehabilitate individuals with upper limb impairments we have developed a wearable exoskeleton robot (ETS-MARSE), designed to be worn on the lateral side of the upper arm. In this paper, we have implemented Cartesian trajectory tracking of the ETS-MARSE. Experiments involved passive rehabilitation exercises (e.g., reaching movement) in three healthy human subjects. Cartesian trajectory tracking involving square shaped trajectories or multijoint reaching movements are widely used for passive arm movement therapy. As control strategies, a computationally inexpensive PID control and a sliding mode exponential reaching law control were used to maneuver the ETS-MARSE. Experimental results show that the ETS-MARSE can be maneuvered effectively to track the Cartesian trajectories which correspond to typical passive arm movement exercises.

Cartesian Trajectory Tracking of a 7-DOF Exoskeleton Robot Based on Human Inverse Kinematics

Exoskeleton robots have become an important tool to provide rehabilitation therapy to stroke victims because of their ability to allow rehabilitation exercises, ranging from passive to active-assisted movement, for extended time periods. To generate the desired rehabilitation trajectories and ensure an optimal Cartesian solution, we propose a new solution to the inverse kinematics problem, which is compatible with human upper limb movement and is valid for human arm configuration. In addition, in order to provide passive rehabilitation therapy to the upper extremity of disabled individuals, we implement a robust nonlinear control based on the backstepping technique on the 7-degrees-of-freedom ETS-MARSE robot. The controller was designed to reject the user’s force caused by the subject’s muscular activity. Experimental results validate the stability, robustness, and exactness of the proposed method with the designed tests performed by healthy subjects.

A new adaptive super-twisting control for an exoskeleton robot with dynamic uncertainties

Advanced robotic technology has become a significant component in many medical specialties, including in rehabilitation tasks such as physiotherapy. Rehabilitation programs are a practical approach created to assist patients, such as stroke victims, in retrieving their missing functional capacity, obtaining new skills, and enhancing their quality of life. Nevertheless, rehabilitation treatments need intensive and demanding effort by the therapist. Lately, robotic rehabilitation has attracted attention from the scientific community since robots are capable of supplementing the treatments provided by conventional physical therapy. The importance of the rehabilitation robots lies in their capability to provide intensive physiotherapy for a long period of time. The feedback data of the robot allow the physiotherapist to carefully evaluate the patients performance. A critical aspect is that the design of this class of robots must be harmonious with human anatomy. In order to provide a modern rehabilitation approach for the upper limb, we have developed an exoskeleton robot that is compatible with the human arm configuration and is able to achieve different rehabilitation movements and assistive tasks.

HELIOS: The human machine interface for MARSE robot

This paper presents preliminary results of the HELIOS software, a human machine interface developed to drive a wearable robot (MARSE) to provide rehabilitation therapy to the patients having impaired upper limb functions. The software was designed to increase the attractiveness of using the MARSE with a simple interface, which is easy to handle and allows visualization of a set of practical exercises used by clinicians/therapists. To evaluate the usability of the HELIOS experiments involving healthy male subjects were performed with the MARSE robot.