Robotic Gait Research Articles

Research on Gait Switching Control of Quadruped Robot Based on Dynamic and Static Combination

To improve the adaptability of quadruped robot to different terrain and ensure the posture stability of the robot body during gait switching, it is necessary to plan different gaits for quadruped robot. This paper mainly studies the switching among three different gaits, and a switching control method of quadruped robot gait based on the dynamic and static combination is proposed, which includes intermittent static gait is switched to non-intermittent gait, non-intermittent gait is switched to trot gait. Firstly, this paper takes quadruped robot as the research object, the SolidWorks is used to conduct three-dimensional modeling, and the D-H algorithm is used to deduce the kinematics equation of a single leg. Then, the stability margin theory and the walking gait model of the quadruped robot is analyzed, and the gait switching strategy is formulated and the stability of the switching process is studied. Meanwhile, the important parameters affecting the motion stability of the robot during the switching process are analyzed, and the trajectory of the switching gait is planned by Matlab. In addition, based on Matlab-Adams co-simulation analysis and physical prototype experiment analysis, the simulation and experimental resulted verify the feasibility and effectiveness of the proposed quadruped robot gait switching control strategy based on dynamic and static combination.

Nonlinear Modeling and Analysis of Stable Behavior of Robot Gait Control System Based on Image Processing Technology

Nonlinear Modeling and Analysis of Stable Behavior of Robot Gait Control System Based on Image Processing Technology

Research on obstacle climbing gait structure design and gait control of hexapod wall climbing robot based on STM32F103 core controller

The hexapod wall climbing robots have the advantages of traversing complex wall surfaces. To traverse complex environments autonomously, it must possess the capability to select gait parameters and paths appropriate for the wall surface. Path planning and gait optimization is a fundamental issue in the aspect of stable, energy efficient robot navigation in complex environments with static and dynamic obstacles. Traditional statistical models have been developed to get the optimal path and gait parameters but the result obtained was very poor. Metaheuristic algorithms are gaining importance in robotic gait planning. In this paper, we proposed robust two stage gait planning approach for predicting collision-free, distance-minimal, smooth navigation path and ensuring stable, energy efficient gait patterns for robots using hybrid metaheuristic algorithms. In the first stage, optimal climbing path for robot is predicted using Tri-objective Grey Wolf Path Optimization (TGWPO) based on obstacle and target detection. In the second stage, the gait parameters adaptive to the constructed climbing path are optimized using Adaptive multi-objective Particle swarm optimization (AMPSO). The hexapod wall climbing robot is designed with STM32F103 as core controller modeled with optimal path planner (using TDWPO) and gait optimizer module (using AMPSO). STM32F103 controller commands and controls the robot to climb on wall with optimized gait parameters according to the optimal path. We analyzed the efficacy of the proposed two stage gait planning approach using TDWPO-AMPSO for hexapod wall climbing robots with existing gait planning approaches in terms of path length, climbing time, gait stability, obstacle avoidance, and energy efficiency. The result analysis showed that the suggested gait planning approach is efficient over conventional strategies for climbing robots.

Nonlinear modelling and analysis of stable behaviour of robot gait control system based on image processing technology

Nonlinear modelling and analysis of stable behaviour of robot gait control system based on image processing technology

Rehabilitation in Ataxia

Ataxic disorders are numerous and relatively uncommon. They can result in lesions in the cerebellum, spinal cord, thalamic nuclei, vestibular nuclei, cerebral white matter and sensory pathways. Ataxia can be acute, subacute or chronic onset and progressive in nature. As pharmacological treatment, especially in chronic and progressive ataxia, is efficient nor is generally effective in treating various issues, rehabilitation has an important role to play in alleviating symptoms and quality of life. Various rehabilitation strategies such as conventional physical and occupational therapy, gait training and coordination therapy have been used for a long time. In the last 3–4 decades, there has been an addition in the armamentarium of rehabilitation with the use of non-invasive brain stimulation, virtual reality, body weight support treadmill training and robotic gait training to improve various aspects of the illness. The current evidence with rehabilitation strategies is also insufficient, so further longitudinal studies with bigger sample size and specific goal-directed therapies are the need of the hour.

Gait robot-assisted rehabilitation in persons with spinal cord injury: A scoping review.

Many robots are available for gait rehabilitation (BWSTRT and ORET) and their application in persons with SCI allowed an improvement of walking function. The aim of the study is to compare the effects of different robotic exoskeletons gait training in persons with different SCI level and severity. Sixty-two studies were included in this systematic review; the study quality was assessed according to GRADE and PEDro's scale. Quality assessment of included studies (n = 62) demonstrated a prevalence of evidence level 2; the quality of the studies was higher for BWSTRT (excellent and good) than for ORET (fair and good). Almost all persons recruited for BWSTRT had an incomplete SCI; both complete and incomplete SCI were recruited for ORET. The SCI lesion level in the persons recruited for BWSTRT are from cervical to sacral; mainly from thoracic to sacral for ORET; a high representation of AIS D lesion resulted both for BWSTRT (30%) and for ORET (45%). The walking performance, tested with 10MWT, 6MWT, TUG and WISCI, improved after exoskeleton training in persons with incomplete SCI lesions, when at least 20 sessions were applied. Persons with complete SCI lesions improved the dexterity in walking with exoskeleton, but did not recover independent walking function; symptoms such as spasticity, pain and cardiovascular endurance improved. Different exoskeletons are available for walking rehabilitation in persons with SCI. The choice about the kind of robotic gait training should be addressed on the basis of the lesion severity and the possible comorbidities.

Neuromodulation with transcutaneous spinal stimulation reveals different groups of motor profiles during robot-guided stepping in humans with incomplete spinal cord injury.

Neuromodulation via spinal stimulation has been investigated for improving motor function and reducing spasticity after spinal cord injury (SCI) in humans. Despite the reported heterogeneity of outcomes, few investigations have attempted to discern commonalities among individual responses to neuromodulation, especially the impact of stimulation frequencies. Here, we examined how exposure to continuous lumbosacral transcutaneous spinal stimulation (TSS) across a range of frequencies affects robotic torques and EMG patterns during stepping in a robotic gait orthosis on a motorized treadmill. We studied nine chronic motor-incomplete SCI individuals (8/1 AIS-C/D, 8 men) during robot-guided stepping with body-weight support without and with TSS applied at random frequencies between 1 and up to 100Hz at a constant, individually selected stimulation intensity below the common motor threshold for posterior root reflexes. The hip and knee robotic torques needed to maintain the predefined stepping trajectory and EMG in eight bilateral leg muscles were recorded. We calculated the standardized mean difference between the stimulation conditions grouped into frequency bins and the no stimulation condition to determine changes in the normalized torques and the average EMG envelopes. We found heterogeneous changes in robotic torques across individuals. Agglomerative clustering of robotic torques identified four groups wherein the patterns of changes differed in magnitude and direction depending mainly on the stimulation frequency and stance/swing phase. On one end of the spectrum, the changes in robotic torques were greater with increasing stimulation frequencies (four participants), which coincided with a decrease in EMG, mainly due to the reduction of clonogenic motor output in the lower leg muscles. On the other end, we found an inverted u-shape change in torque over the mid-frequency range along with an increase in EMG, reflecting the augmentation of gait-related physiological (two participants) or pathophysiological (one participant) output. We conclude that TSS during robot-guided stepping reveals different frequency-dependent motor profiles among individuals with chronic motor incomplete SCI. This suggests the need for a better understanding and characterization of motor control profiles in SCI when applying TSS as a therapeutic intervention for improving gait.

Early Initiation of Exoskeletal Robotic Gait Training Improves Functional Outcomes in the Patients with Stroke: A Retrospective Observational Study

Introduction: The effect of early initiation of gait training using hybrid assistive limb (HAL) remains unclear. This observational study aimed to investigate whether early initiation of gait training using HAL improves functional outcomes in patients with stroke. Methods: We retrospectively analyzed patients with acute stroke admitted to our facility. HAL was used for exoskeletal robotic gait training. Study participants were median split into an early group and a late group based on the days from stroke onset to initiation of gait training using HAL. The functional outcomes, defined by the Brunnstrom recovery stage (BRS), modified Rankin Scale (mRS), and Functional Independence Measure (FIM) at discharge, were compared using propensity score-matched analysis. Results: We performed a propensity score-matched analysis in 63 patients with stroke (31 from the early group and 32 from the late group), and 17 pairs were matched. There were no significant differences in discharge in the BRS of the upper limb and finger in the post-matched cohort. On the other hand, the BRS of the lower limb in the early group was significantly higher than that in the late group. In addition, the mRS, but not FIM scores, was significantly better in the early group than that in the late group. Conclusions: In conclusion, early initiation of gait training using HAL might improve the motor function of the paralyzed lower limb and disability in patients with stroke.

Long-Term Retention of Robotic Gait Training: Transference From The Laboratory To The Real-World

<h3>Research Objectives</h3> Investigate the long-term retention of effects on gait and mobility after a robotic treadmill gait training protocol (TT) plus a transfer package (TP). <h3>Design</h3> Preliminary RCT findings of a six-week robotic treadmill training combined with behavioral strategies. Outcomes measured pre-, immediately after (post), and at 3-month follow-up (FU). <h3>Setting</h3> Clinical Research Unit. <h3>Participants</h3> 7 participants (>6 months poststroke); walking impairment, can walk ≤10 feet. Randomized to experimental (n=4) or control groups (n=3). <h3>Interventions</h3> All participants receive the same TT protocol. The experimental group (TT+TP) receives TT, and 30 minutes of behavioral strategies (TP) application to enhance motor skill transference outside clinical settings. Controls (TT) receive home exercise handouts plus TT. The 6-week intervention involves three 30-minute TT sessions a week targeting endurance, strength, and speed. <h3>Main Outcome Measures</h3> Lower Extremity Motor Activity Log (LE-MAL), Berg Balance Scale (BBS), 10MWT, 6MWT, Fear of Falling Avoidance Questionnaire (FFABQ). <h3>Results</h3> On average, all participants improved on all post-pre assessments. TT+TP participants showed continuous improvement at FU. LE-MAL (TT post-pre: 0.6 and: -0.6; TT+TP post-pre: 1.0 and FU: 0.2), BBS (TT post-pre: 1.3 and FU: -1.0; TT+TP post-pre: 1.5 and FU: 0.7), 10MWT self-selected speed: TT post-pre: 0.03m/s and FU: -0.15m/s; TT+TP post-pre: 0.01m/s and FU: 0.04 m/s, 10MWT fast speed: TT post-pre: 0.02 m/s and FU: 0.0.3 m/s; TT+TP post-pre: -0.01 m/s and FU: 0.08 m/s, 6MWT TT post-pre: 22.2 m and FU: 10.7 m/s; TT+TP post-pre: 13.8 m and FU: 17.4 m, and FFABQ (lower scores mean lower avoidance behavior), TT post-pre: -5 and FU: 0.7; TT+TP post-pre: -3.3 and FU: -3.25. <h3>Conclusions</h3> This preliminary analysis suggests the TT+TP group retains TT improvements. Adding behavioral strategies to robotic gait training may induce long-term retention of improvements in TT, endurance, balance, and confidence. <h3>Author(s) Disclosures</h3> DB has a potential conflict of interest, please refer to author disclosure of information for details. The other authors have no conflict of interest to declare.

A novel gait analysis system for detecting abnormal hemiparetic gait patterns during robot-assisted gait training: A criterion validity study among healthy adults.

Robot-assisted gait training has been reported to improve gait in individuals with hemiparetic stroke. Ideally, the gait training program should be customized based on individuals' gait characteristics and longitudinal changes. However, a gait robot that uses gait characteristics to provide individually tailored gait training has not been proposed. The new gait training robot, "Welwalk WW-2000," permits modification of various parameters, such as time and load of mechanical assistance for a patient's paralyzed leg. The robot is equipped with sensors and a markerless motion capture system to detect abnormal hemiparetic gait patterns during robot-assisted gait training. Thus, it can provide individually tailored gait training. This study aimed to investigate the criterion validity of the gait analysis system in the Welwalk WW-2000 in healthy adults. Twelve healthy participants simulated nine abnormal gait patterns that were often manifested in individuals with hemiparetic stroke while wearing the robot. Each participant was instructed to perform a total of 36 gait trials, with four levels of severity for each abnormal gait pattern. Fifteen strides for each gait trial were recorded using the markerless motion capture system in the Welwalk WW-2000 and a marker-based three-dimensional (3D) motion analysis system. The abnormal gait pattern index was then calculated for each stride from both systems. The correlation of the index values between the two methods was evaluated using Spearman's rank correlation coefficients for each gait pattern in each participant. Using the participants' index values for each abnormal gait pattern obtained using the two motion analysis methods, the median Spearman's rank correlation coefficients ranged from 0.68 to 0.93, which corresponded to moderate to very high correlation. The gait analysis system in the Welwalk WW-2000 for real-time detection of abnormal gait patterns during robot-assisted gait training was suggested to be a valid method for assessing gait characteristics in individuals with hemiparetic stroke. [https://jrct.niph.go.jp], identifier [jRCT 042190109].

Synthesizing the optimal gait of a quadruped robot with soft actuators using deep reinforcement learning

Quadruped robots have the advantages of traversing complex terrains that are difficult for wheeled robots. Most of the reported quadruped robots are built by rigid parts. This paper proposes a new design of quadruped robots using soft actuators driven by tendons as the four legs. Compared to the rigid robots, the proposed soft quadruped robot has inherent safety, less weight and simpler mechanism for fabrication and control, but the corresponding challenge is that the accurate mathematical model applicable to model-based control design of the soft robot is difficult to derive by dynamics. To synthesize the optimal gait controller of the soft-legged robot, the paper makes the following contributions. First, the flexible components of the quadruped robot are modeled with different finite element and lumped parameter methods. The model accuracy and computation efficiency are analyzed. Second, soft actor–critic methods and curriculum learning are applied to learn the optimal gaits for different walking tasks. Third, The learned gaits are implemented in an in-house robot to transport hand tools. Preliminary results show that the robot can walk forward and correct the walking directions.

Novel Robotics-Treadmill-Platform Application To Improve Walking In A Person With Parkinson's Disease: A Case Report

<h3>Research Objectives</h3> Illustrate the potential benefits of a 6-week novel Robotic treadmill system training protocol, focused on implicit learning of challenging tasks, on walking performance in an older adult with Parkinson's Disease. <h3>Design</h3> A single-subject case report. <h3>Setting</h3> Outpatient rehabilitation clinic in the southwestern U.S. <h3>Participants</h3> An 82-year-old-female with a 3-year history of Parkinson's disease (PD) on carbidopa/levodopa (Hoehn and Yahr stage 1) was referred to physical therapy (PT) to improve performance and safety of walking. <h3>Interventions</h3> Twelve twice-weekly PT sessions on the walking robotics platform (KineAssist). The platform allows "self-driven"/intentional movement on the treadmill with body weight support, catching after loss of balance, and including full freedom of movement. The protocol emphasized progressive Endurance, Strength, Speed, and Perturbation exercises individualized to her abilities. <h3>Main Outcome Measures</h3> . The primary outcomes were the overground 6-Min-Walk Test (6MWT), TUG, TUG Carry, TUG Cognitive, and Mini-Best test. Secondary outcomes included 10-Meter-Walk-Test (10MWT) self-selected and max walking speeds assessed via the Robotic treadmill system. <h3>Results</h3> The 6MWT improved 51% (318-481m); the TUG score improved 53% (10.3-5.5 sec); the TUG Carry, 50% faster (13.7- 6.8 sec); the TUG Cognitive, 50% faster (13.2- 6.5 sec), the Mini-Best Test improved 8 points (18/28-26/28). The self-selected 10MWT speed improved 196% (0.27- 0.8 m/s) and max gait speed by 120% (1.0-2.2 m/s). <h3>Conclusions</h3> An individualized robotic treadmill gait training protocol was used successfully with an older patient with PD, with marked improvement in her walking, exceeding available minimal clinically important distances for all outcome measures. An implicit learning approach, combined with a robotic treadmill, may enable individuals to perform challenging tasks without fear of physical harm and to develop strategies for safe mobility in their environment. <h3>Author(s) Disclosures</h3> The authors declare that they have no relevant or material financial interests related to the research described in this abstract. Dr. Brown is a Co-inventor of a device described in the presentation, but he currently DOES NOT receive any royalties.

Rehabilitation of Post-COVID-19 Musculoskeletal Sequelae in Geriatric Patients: A Case Series Study.

The musculoskeletal system is affected in over 40% of patients with Coronavirus disease 2019 (COVID-19). There is an increased need for post-acute rehabilitation after COVID-19, especially in elderly people with underlying health problems. The aim of this study was to evaluate the benefits of an early and goal-orientated rehabilitation program using combined approaches, robotic medical devices together with other rehabilitation techniques and therapies, in elderly people after acute COVID-19. Ninety-one patients (62.64 ± 14.21 years) previously diagnosed with severe SARS-CoV-2 infection were admitted to the Medical Rehabilitation Clinical Hospital Baile Felix, Romania, for medical rehabilitation, but only six patients (85.33 ± 3.07 years) met the inclusion criteria and participated in the study. The rehabilitation treatment was complex, performed over 4 weeks, and included combined approaches: exercise therapy, robotic gait training, occupational therapy, and massages. Activity and participation evaluation were performed using the Barthel Index and Functional Independence Measure for activities of daily living (ADLs). Assessments were performed at admission and discharge from the rehabilitation clinic. Lokomat patients' reports revealed that the patients had improved motor control (with one exception). The measurement of functional ability revealed an improvement in most cases. This study presents some of the first data on outcomes of COVID-19 patients' musculoskeletal rehabilitation in our country. Early complex medical rehabilitation improved functional independence and autonomy in ADLs in very old patients, post-COVID-19.

A self‐stabilised walking gait for humanoid robots based on the essential model with internal states

AbstractWalking stability is one of the key issues for humanoid robots. A self‐stabilised walking gait for a full dynamic model of humanoid robots is proposed. For simplified models, that is, the linear inverted pendulum model and variable‐length inverted pendulum model, self‐stabilisation of walking gait can be obtained if virtual constraints are properly defined. This result is extended to the full dynamic model of humanoid robots by using an essential dynamic model, which is developed based on the zero dynamics concept. With the proposed method, a robust stable walking for a humanoid robot is achieved by adjusting the step timing and landing position of the swing foot automatically, following its intrinsic dynamic characteristics. This exempts the robot from the time‐consuming high‐level control approaches, especially when a full dynamic model is applied. How different walking patterns/features (i.e., the swing foot motion, the vertical centre of mass motion, the switching manifold configuration, etc.) affect the stability of the walking gait is analysed. Simulations are conducted on robots Romeo and TALOS to support the results.

Efficacy and evaluation of therapeutic exercises on adults with Parkinson’s disease: a systematic review and network meta-analysis

BackgroundExercises are an effective treatment in Parkinson’s disease (PD), but there is still controversy over which types should be used. We aimed to compare and rank the types of exercise that improve PD symptoms by quantifying information from randomised controlled trials.MethodsWe performed a systematic review and network meta-analysis and searched PubMed, MEDLINE, Embase, PsycINFO, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and China National Knowledge Infrastructure (CNKI) from their inception date to June 30, 2022. We included randomized controlled trials of 24 types of exercise for the interventional treatment of adults (≥ 50 years old) with PD. Effect size measures were standardized mean differences (SMDs) with 95% credible intervals (CrIs). The confidence of evidence was examined using Confidence in Network Meta-Analysis (CINeMA).ResultsWe identified 10 474 citations and included 250 studies involving 13 011 participants. Results of NMA showed that power training (PT) had the best benefits for motor symptoms compared with the control group (CON), with SMDs (95% CrI) (-1.46, [-2.18 to -0.74]). Body weight support treadmill training (BWS_TT) showed the best improvement in balance (1.55, [0.72 to 2.37]), gait velocity (1.15 [0.57 to 1.31]) and walking distance (1.96, [1.18 to 2.73]), and robotic assisted gait training (RA_GT) had the most benefits for freezing of gait (-1.09, [-1.80 to -0.38]). For non-motor symptoms, Dance showed the best benefits for depression (-1.71, [-2.79 to -0.73]). Only Yoga significantly reduced anxiety symptom compared with CON (-0.53, [0.96 to -0.11]). Only resistance training (RT) significantly enhanced sleep quality and cognition (-1.42, [-2.60 to -0.23]; 0.51, [0.09 to 0.94]). For muscle strength, PT showed the best advance (1.04, [0.64 to 1.44]). For concern of falling, five types of exercise were more effective than CON.ConclusionsThere is low quality evidence that PT, Yoga, BWS_TT, Dance, and RT are the most effective treatments, pending outcome of interest, for adults with PD.Trial registrationPROSPERO (CRD42021220052).

The Foot and Ankle Kinematics of a Simulated Progressive Collapsing Foot Deformity During Stance Phase: A Cadaveric Study.

Progressive collapsing foot deformity (PCFD) is a complex pathology associated with tendon insufficiency, ligamentous failure, joint malalignment, and aberrant plantar force distribution. Existing knowledge of PCFD consists of static measurements, which provide information about structure but little about foot and ankle kinematics during gait. A model of PCFD was simulated in cadavers (sPCFD) to quantify the difference in joint kinematics and plantar pressure between the intact and sPCFD conditions during simulated stance phase of gait. In 12 cadaveric foot and ankle specimens, the sPCFD condition was created via sectioning of the spring ligament and the medial talonavicular joint capsule followed by cyclic axial compression. Specimens were then analyzed in intact and sPCFD conditions via a robotic gait simulator, using actuators to control the extrinsic tendons and a rotating force plate underneath the specimen to mimic the stance phase of walking. Force plate position and muscle forces were optimized using a fuzzy logic iterative process to converge and simulate in vivo ground reaction forces. An 8-camera motion capture system recorded the positions of markers fixed to bones, which were then used to calculate joint kinematics, and a plantar pressure mat collected pressure distribution data. Joint kinematics and plantar pressures were compared between intact and sPCFD conditions. The sPCFD condition increased subtalar eversion in early, mid-, and late stance (P < .05), increased talonavicular abduction in mid- and late stance (P < .05), and increased ankle plantarflexion (P < .05), adduction (P < .05), and inversion (P < .05). The center of plantar pressure was significantly (P < .01) medialized in this model of sPCFD and simulated stance phase of gait. Subtalar and talonavicular joint kinematics and plantar pressure distribution significantly changed with the sPCFD and in the directions expected from a PCFD foot. We also found that ankle joint kinematics changed with medial and plantar drift of the talar head, indicating abnormal talar rotation. Although comparison to an in vivo PCFD foot was not performed, this sPCFD model produced changes in foot kinematics and indicates that concomitant abnormal changes may occur at the ankle joint with PCFD. This study describes the dynamic kinematic and plantar pressure changes in a cadaveric model of simulated progressive collapsing foot deformity during simulated stance phase.

Kinematic Analysis of Sequential Partial-Midfoot Arthrodesis in Simulated Gait Cadaver Model.

Primary tarsometatarsal (TMT) arthrodesis is gaining popularity in the surgical treatment of Lisfranc injuries. However, few studies have evaluated biomechanical effects of TMT arthrodesis. The purpose of this study was to compare the kinematics of joints adjacent to the midfoot during simulations of stance before and after sequential arthrodesis of the first, second, and third TMT joints. Ten midtibia cadaveric specimens were loaded on a 6-degree-of-freedom robotic gait simulator. Motion capture cameras were used to collect joint kinematics throughout simulations of the stance phase. Simulations were performed for the intact and sequential arthrodesis conditions of the first, second, and third TMT joints. The sagittal, coronal, and transverse plane rotational kinematics of the intact condition were compared to kinematics after each sequential arthrodesis condition. Sequential arthrodesis of the first and second TMT joints had no significant effect on ankle, subtalar, talonavicular, and first metatarsophalangeal joint motion during simulated stance when compared to the intact condition. In contrast, inclusion of the third TMT joint into the sequential arthrodesis significantly increased subtalar inversion (P = .032) in late stance and increased range of motion values in the ankle and subtalar joints by 2.1 degrees (P = .009) and 2.8 degrees (P = .014), respectively. Sequential primary arthrodesis induced changes to ankle and adjacent joint kinematics during stance phase simulations, although not until the third TMT joint was included into the primary arthrodesis. The significant changes to kinematics due to arthrodesis of the first, second, and third TMT joints were small. The minimal changes in sagittal, coronal, and transverse plane rotational kinematics support the positive clinical outcomes reported in the literature for primary partial arthrodesis of Lisfranc injuries. The inclusion of the third TMT joint should be done judiciously.

Improvement of Gait after Robotic-Assisted Training in Children with Cerebral Palsy: Are We Heading in the Right Direction?

Cerebral palsy (CP) is a non-progressive congenital neurological disorder that affects different physical and cognitive functions in children. In addition to standard rehabilitation, advanced robotic gait devices are novel tools that are becoming progressively more common as part of the treatment of CP. The aim of this study is to evaluate the effects of Lokomat training, in addition to conventional rehabilitation, on the motor function and quality of life of children with ataxic-spastic CP (ASCP). Ten children with ASCP who attended the Robotic Rehabilitation OutClinic of the IRCCS Centro Neurolesi "Bonino Pulejo", from April to June 2019, were enrolled in this study. They received twenty-four robotic rehabilitation sessions, twice a week for three months, each session lasting about 45 min. They were also provided with conventional physical and occupational therapy. After the innovative training, we found significant changes in the children's outcomes, i.e., in GMFM (p < 0.001), with significant improvements in sitting (p < 0.03) and walking (p < 0.03). Moreover, the quality of life of the young patients, evaluated by their parents, significantly improved (p < 0.005). The use of robotic systems could be considered to be an effective complementary treatment to improve gait, as well as quality of life, in children with CP.

Planning of Obstacle-Aided Navigation for Multi-Legged Robots Using a Sampling-Based Method Over Directed Graphs

Existing work in legged robot navigation in cluttered environments often seeks collision-free paths that avoid obstacle interactions. Here we present a new approach for multi-legged robots to utilize leg-obstacle collisions to generate desired dynamics. To predict the change of robot state under repeated leg-obstacle collisions, we construct a discretized directed graph model: each node of the graph represents a different robot state, whereas the directed edges pointing from one node to another represent the transitions from one robot state to the next within one stride. These obstacle-modulated state transitions can depend on the robot gaits used. To capture this dependence, an empirical interaction model is used to compute the change of robot state based on initial contact positions between robot legs and obstacles. To validate the prediction of robot state transitions, we experimentally measure the state of a quadrupedal robot as it traverses a periodic obstacle field with three different gaits: bound, trot, and pace. We observed that the robot could passively converge to different steady state orientations, and these steady states corresponded well with the Strongly-Connected-Path-Components (SCPCs) within the directed graph. Searching over the graph for connected paths of SCPCs allows development of a gait planner that can generate gait switching strategies for a robot to achieve desired states by simply engaging with a sequence of leg-obstacle collisions. We demonstrate in experiments that using this method an open-loop quadrupedal robot was able to achieve desired orientations within a periodic obstacle field without any sensory input or active steering.

Insect-Scale SMAW-Based Soft Robot With Crawling, Jumping, and Loading Locomotion

The work develops an insect-scale soft robot capable of fast directional locomotion actuated by itself spring-like body composed of shape memory alloy wires (SMAWs)-based composite. The soft composite is fabricated integrating polydimethylsiloxane (PDMS) matrix, 3D printed acrylonitrile-butadiene-styrene (ABS) substrate, and parallel multi-SMAWs with the diameter of 0.075 mm. Since it can implant the thermal-induced SMAW deformation and rapidly cause the elastic recovery feature of ABS resin material, the soft composite can act as the insect-scale robotic actuator to imitate the longitudinal muscle. The designed structure can convert the repetitive contraction-stretch behavior of the embedded SMAWs to the bending-expanding deformation of the robotic soft body, which forms the robotic different gaits. With the excitation of pulse-width modulation (PWM) voltages with various frequencies, different characteristics of the designed robot are compared. The experimental results validate that the designed soft robot can reach a movement speed of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 29.87 mm/s with jumping locomotion, greater than one-time body-length/s, and afford a load of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 11.1 g, about 24.1 times the weight of itself.