Design and Motion Control of a Lower Limb Robotic Exoskeleton

This chapter presents the results of research work on design, actuator selection and motion control of a lower extremity exoskeleton developed to provide legged mobility to spinal cord injured (SCI) individuals. The exoskeleton has two degrees of freedom per leg. Hip and knee joints are actuated in the sagittal plane by using DC servomotors. Additional effort supplied by user’s arms through crutches is defined as user support rate (USR). Experimentally determined USR values are considered in actuator torque computations for achieving a realistic actuator selection. A custom-embedded system is used to control exoskeleton. Reference joint trajectories are determined by using clinical gait analysis (CGA). Three-loop cascade controllers with current, velocity and position feedback are designed for controlling the joint motions of the exoskeleton. A non-linear ARX model is used to determine controller parameters. Overall performance and an assistive effect of WSE-2 are experimentally investigated by conducting tests with a paraplegic patient with T10 complete injury

A mechatronic device for spasticity quantification

Spasticity is a common and complex motor disorder that affects more than 12 million persons in the world. There are several studies on spasticity quantification in the literature but there is still a need for measurement improvements. This paper presents the design of a mechatronic device for spasticity quantification, in joint of ankle, elbow and knees. This approach is based on the velocity dependent of the tonic stretch reflexes. The relevant variables, the measurement range and the adequate measurement systems are selected. The data acquisition system, board and software, are also defined and tested in laboratory. The proposed system was tested in rehabilitation clinical environment and the corresponding results are presented in this article.The authors are grateful to Portuguese Research Centers Algoritmi and CT2M for financial support. The authors are also grateful to Fisimaia rehabilitation clinic in Maia and his patients

Development of a mechatronic system for the mirror therapy

This paper fits into the field of research concerning robotic systems for rehabilitation. Robotic systems are going to be increasingly used to assist fragile persons and to perform rehabilitation tasks for persons affected by motion injuries. Among the recovery therapies, the mirror therapy was shown to be effective for the functional recovery of an arm after stroke. In this paper we present a master/slave robotic device based on the mirror therapy paradigm for wrist rehabilitation. The device is designed to orient the affected wrist in real time according to the imposed motion of the healthy wrist. The paper shows the kinematic analysis of the system, the numerical simulations, an experimental mechatronic set-up, and a built 3D-printed prototype

Mechatronic design, experimental setup, and control architecture design of a novel 4 DoF parallel manipulator

"This is an Author's Accepted Manuscript of an article published in [include the complete citation information for the final versíon of the article as published in the Mechanics Based Design of Structures and Machines 2018 [copyright Taylor & Francis], available online at: https://www.tandfonline.com/doi/10.1080/15397734.2017.1355249."[EN] Although parallel manipulators started with the introduction of architectures with six degrees of freedom, a vast number of applications require less than six degrees of freedom. Consequently, scholars have proposed architectures with three and four degrees of freedom, but relatively few four degrees of freedom parallel manipulators have become prototypes, especially of the two rotation and two translation motion types. In this article, we explain the mechatronics design, prototype, and control architecture design of a four degrees of freedom parallel manipulators with two rotation and two translation motions. We chose to design a four degrees of freedom manipulator based on the motion needed to complete the tasks of lower limb rehabilitation. To the author's best knowledge, parallel manipulators between three and six degrees of freedom for rehabilitation of lower limb have not been proposed to date. The developed architecture enhances the three minimum degrees of freedom required by adding a four degrees of freedom, which allows combinations of normal or tangential efforts in the joints, or torque acting on the knee. We put forward the inverse and forward displacement equations, describe the prototype, perform the experimental setup, and develop the hardware and control architecture. The tracking accuracy experiments from the proposed controller show that the manipulator can accomplish the required application.The authors wish to thank the Plan Nacional de I + D, Comision Interministerial de Ciencia y Tecnologia (FEDER-CICYT) for the partial funding of this study under project DPI2013-44227-R. We also want to thank the Fondo Nacional de Ciencia, Tecnologia e Innovacion (FONACIT-Venezuela) for its financial support under the project No. 2013002165.Vallés Miquel, M.; Araujo-Gómez, P.; Mata Amela, V.; Valera Fernández, Á.; Díaz-Rodríguez, M.; Page Del Pozo, AF.; Farhat, N. (2018). Mechatronic design, experimental setup, and control architecture design of a novel 4 DoF parallel manipulator. Mechanics Based Design of Structures and Machines. 46(4):425-439. https://doi.org/10.1080/15397734.2017.1355249S425439464Araujo-Gómez, P., Díaz-Rodriguez, M., Mata, V., Valera, A., & Page, A. (2016). Design of a 3-UPS-RPU Parallel Robot for Knee Diagnosis and Rehabilitation. 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Robot-assisted ankle rehabilitation for the treatment of drop foot: A case study

This paper involves the use of an intrinsically-compliant ankle rehabilitation robot for the treatment of drop foot. The robot has a bio-inspired design by employing four Festo fluidic actuators that mimic skeletal muscles to actuate three rotational degrees of freedom (DOFs). A position controller in task space was developed to track the predefined trajectory of the end effector. The position tracking was achieved by the length tracking of each actuator in joint space by inverse kinematics. A stroke patient with drop foot participated in the trial as a case study to evaluate the potential of this robot for clinical applications. The patient gave positive feedback in using the ankle robot for the treatment of drop foot, although some limitations exist. The trajectory tracking showed satisfactory accuracy throughout the whole training with varying ranges of motion, with the root mean square deviation (RMSD) value being 0.0408 rad and the normalized root mean square deviation (NRMSD) value being 8.16%. To summarize, preliminary findings support the potential of the ankle rehabilitation robot for clinical applications. Future work will investigate the effectiveness of the robot for treating drop foot on a large sample of subjects

Investigation of a mechatronic device for the remedial treatment of brain injured children.

To speed the recovery of brain injured children using the method of patterning; it must be made efficient. Efficiency can be achieved by automating the manual method, which will provide the patients with the necessary stimuli needed to help them enhance/restore their natural mobility. This thesis describes research into a novel moderate-cost single-axis Mechatronics device for the remedial treatment of brain injured patients. The device will enhance and/or improve their natural mobility by stimulating the undamaged brain cells responsible for mobility in the central nervous system through physical activity. A detailed review of rehabilitation robotics was undertaken, covering more than seventy projects relating to disabled people. This review helped to identify the main areas of this research regarding the most suitable structure of the machine and setting up the design specifications for the device. A critical investigation of past and present patterning machines and workstations helped avoid the mistakes made by previous designers in not including brain-injured patients in the initial stages of the design. Use of high technology video equipment has made practicable the development of mathematical expressions based on experimental data for the movements of human arms, feet and head. Measurements taken and ergonomic data used made it possible to implement a realistic practical novel kinematic arrangement for the patterning machine. A thorough review of direct drive electrical actuators, and surveys and measurements of the human body with respect to the kinematic arrangements, resulted in the selection of the most appropriate actuator for each axis. The selection of the motor and gearbox was based on the mass of each part of the human body in the prone position, the criteria of high peak torque to motor ratio, low cost, minimum maintenance, safety and compatibility. A computer model of the kinematic arrangement designed was created including the necessary motion constrains, using ADAMS and 3D Working Model simulation packages to test, verify and analyse the static and dynamic stability of the kinematic arrangements and the force interaction between the system and the patient. The simulation results led to some modification in the design regarding the kinematics and dynamic stability of the system by varying different design variables. A walking model of a human was created to simulate the real patient. The model was placed on two units where the feet were the only contact points with the moving belts; the model torso was supported by a harness to hold it in the upright standing position. The results obtained showed the movements of both feet (knees. hips and ankles) in addition to the right and left elbows. The system hardware was designed and implemented using custom-made safety critical software to control the device to carry out the desired tasks. Safety is considered to be one of the main issues that this research program has developed and implemented. An optimal control strategy was developed to drive the prototype. Smooth movements of the system were achieved through a PD control system enhanced with velocity feed forward gain with position accuracy of ± 0.168 mm. The desired positional accuracy of the Patterner Machine was ± 0.632 mm

Mechatronic Design of a Lower Limb Exoskeleton

This chapter presents a lower limb exoskeleton mechatronic design. The design aims to be used as a walking support device focused on patients who suffer of partial lower body paralysis due to spine injuries or caused by a stroke. First, the mechanical design is presented and the results are validated through dynamical simulations performed in Autodesk Inventor and MATLAB. Second, a communication network design is proposed in order to establish a secure and fast data link between sensors, actuators, and microprocessors. Finally, patient‐exoskeleton system interaction is presented and detailed. Movement generation is performed by means of digital signal processing techniques applied to electromyography (EMG) and electrocardiography (EEG) signals. Such interaction system design is tested and evaluated in MATLAB whose results are presented and explained. A proposal of real‐time supervisory control is also presented as a part of the integration of every component of the exoskeleton

Reviewing Clinical Effectiveness of Active Training Strategies of Platform-Based Ankle Rehabilitation Robots

Objective; This review aims to provide a systematical investigation of clinical effectiveness of active training strategies applied in platform-based ankle robots. Method. English-language studies published from Jan 1980 to Aug 2017 were searched from four databases using key words of “Ankle” AND “Robot” AND “Effect OR Improv OR Increas.” Following an initial screening, three rounds of discrimination were successively conducted based on the title, the abstract, and the full paper. Result. A total of 21 studies were selected with 311 patients involved; of them, 13 studies applied a single group while another eight studies used different groups for comparison to verify the therapeutic effect. Virtual-reality (VR) game training was applied in 19 studies, while two studies used proprioceptive neuromuscular facilitation (PNF) training. Conclusion. Active training techniques delivered by platform ankle rehabilitation robots have been demonstrated with great potential for clinical applications. Training strategies are mostly combined with one another by considering rehabilitation schemes and motion ability of ankle joints. VR game environment has been commonly used with active ankle training. Bioelectrical signals integrated with VR game training can implement intelligent identification of movement intention and assessment. These further provide the foundation for advanced interactive training strategies that can lead to enhanced training safety and confidence for patients and better treatment efficacy

Bra.Di.P.O. and P.I.G.R.O.: Innovative Devices for Motor Learning Programs

Two mechatronics prototypes, useful for robotic neurotreatments and new clinical trainings, are here presented. P.I.G.R.O. (pneumatic interactive gait rehabilitation orthosis) is an active exoskeleton with an electropneumatic control. It imposes movements on lower limbs in order to produce in the patient’s brain proper motor cortex activation. Bra.Di.P.O. (brain discovery pneumatic orthosis) is an MR-compatible device, designed to improve fMRI (functional magnetic resonance imaging) analysis. The two devices are presented together because both are involved in the study of new robotic treatments of patients affected by ictus or brain stroke or in some motor learning experimental investigations carried out on healthy subjects