DARPA Robotics Grand Challenge Participation and Ski-Type Gait for Rough-Terrain Walking

In this paper, we briefly introduce the history of the Defense Advanced Research Projects Agency(DARPA) Grand Challenge programs with particular focus on the 2012 Robotics Challenge. As members of team DRC-HUBO, we propose different approaches for the Rough-Terrain task, such as enlarged foot pedals and a transformation into quadruped walking. We also introduce a new gait for humanoid robot locomotion to improve stability performance, called the Ski-Type gait. We analyze the stability performance of this gait and use the stability margin to choose between two candidate step sequences, Crawl-1 and Crawl-2. Next, we perform a force/torque analysis for the redundant closedchain system in the Ski-Type gait, and determine the joint torques by minimizing the total energy consumption. Based on the stability and force/torque analysis, we design a cane length to support a feasible and stable Crawl-2 gait on the HUBO2 humanoid robot platform. Finally, we compare our experimental results with biped walking to validate the SkiType gait. We also present our team performance in the trials of the Robotics Challenge.

Surgical intervention combined with weight-bearing walking training promotes recovery in patients with chronic spinal cord injury:a randomized controlled study

For patients with chronic spinal cord injury,the co nventional treatment is rehabilitation and treatment of spinal cord injury complications such as urinary tract infection,pressure sores,osteoporosis,and deep vein thrombosis.Surgery is rarely perfo rmed on spinal co rd injury in the chronic phase,and few treatments have been proven effective in chronic spinal cord injury patients.Development of effective therapies fo r chronic spinal co rd injury patients is needed.We conducted a randomized controlled clinical trial in patients with chronic complete thoracic spinal co rd injury to compare intensive rehabilitation(weight-bearing walking training)alone with surgical intervention plus intensive rehabilitation.This clinical trial was registered at ClinicalTrials.gov(NCT02663310).The goal of surgical intervention was spinal cord detethering,restoration of cerebrospinal fluid flow,and elimination of residual spinal cord compression.We found that surgical intervention plus weight-bearing walking training was associated with a higher incidence of American Spinal Injury Association Impairment Scale improvement,reduced spasticity,and more rapid bowel and bladder functional recovery than weight-bearing walking training alone.Overall,the surgical procedures and intensive rehabilitation were safe.American Spinal Injury Association Impairment Scale improvement was more common in T7-T11 injuries than in T2-T6 injuries.Surgery combined with rehabilitation appears to have a role in treatment of chronic spinal cord injury patients.

Motivations and barriers to utilizing adult walking buses: An examination of demographic correlates of willingness to participate in a community-based walking program

Walking buses are a way to increase physical activity by encouraging people to walk rather than rely on motorized forms of transportation. Several communities support walking school buses as an alternative mode of pupil transportation to schools. A possible extension of this concept is the introduction of adult walking buses. Given the novelty of the concept, very little is currently known about the public’s perceptions regarding adult walking buses and their potential effectiveness to increase physical activity and decrease obesity among adults. To bridge this gap, this study examined motivations and barriers to participation in an adult walking bus program in Birmingham, Alabama using a comprehensive questionnaire survey. Analysis of over 340 responses revealed a positive reception of the concept among the survey responders. More specifically, 60.1% of the sample reported they would definitely or probably participate in a walking bus program. Results from nested ordinal logistic regression analysis indicate that health benefits are the strongest motivation for willingness to participate in a walking bus program. Sensitivity to environmental issues is also a significant predictor of willingness to participate across models. The most significant barrier to willingness to participate in a walking bus program is limited time. The significance of demographic variables (obesity, race/ ethnicity, and age) as predictors of willingness to participate is reduced once motivations and barriers are controlled. In conclusion, the positive response to the program among our sample is encouraging and suggests that adult walking buses should be explored further as an active alternative transportation option with a potential to improve the health and wellbeing of participants.

DeepSurNet-NSGA II:Deep Surrogate Model-Assisted Multi-Objective Evolutionary Algorithm for Enhancing Leg Linkage in Walking Robots

This research paper presents a comprehensive investigation into the effectiveness of the DeepSurNet-NSGA II(Deep Surrogate Model-Assisted Non-dominated Sorting Genetic Algorithm II)for solving complex multiobjective optimization problems,with a particular focus on robotic leg-linkage design.The study introduces an innovative approach that integrates deep learning-based surrogate models with the robust Non-dominated Sorting Genetic Algorithm II,aiming to enhance the efficiency and precision of the optimization process.Through a series of empirical experiments and algorithmic analyses,the paper demonstrates a high degree of correlation between solutions generated by the DeepSurNet-NSGA II and those obtained from direct experimental methods,underscoring the algorithm’s capability to accurately approximate the Pareto-optimal frontier while significantly reducing computational demands.The methodology encompasses a detailed exploration of the algorithm’s configuration,the experimental setup,and the criteria for performance evaluation,ensuring the reproducibility of results and facilitating future advancements in the field.The findings of this study not only confirm the practical applicability and theoretical soundness of the DeepSurNet-NSGA II in navigating the intricacies of multi-objective optimization but also highlight its potential as a transformative tool in engineering and design optimization.By bridging the gap between complex optimization challenges and achievable solutions,this research contributes valuable insights into the optimization domain,offering a promising direction for future inquiries and technological innovations.

Effect of Brisk Walking on Self-Care Agency or Care Dependency among Colorectal Cancer Patients with Permanent Stoma

Objective:The purpose of this study was to determine the effectiveness of brisk walking as an intervention for self-care agency and care dependency in patients with permanent colorectal cancer stoma.Method:This study adopted a quasi-experimental research design,specifically a non-equivalent control group pre-test and post-test design.Utilizing the Exercise of Self-Care Agency Scale(ESCA)and Care Dependency Scale(CDS),a survey was administered to 64 patients from a hospital in Shandong Province.The statistical methods used for analyzing data included frequency,mean,standard deviation(SD),independent t-test,P-value calculation,and dependent t-test.Result:After two months of a brisk walking exercise program,participants in the experimental group had a higher level of self-care agency than before the experiment(P<0.05),and their level of care dependency was significantly reduced(P<0.05).Participants in the control group also showed higher levels of self-care agency(P<0.05)and lower levels of care dependency(P<0.05)after two months compared to their levels before the two months.Conclusion:The brisk walking program had a positive impact on patients’self-care agency and reduced their care dependency.

Kinematics and Dynamics Analysis of a Quadruped Walking Robot with Parallel Leg Mechanism

It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple function.Therefore,Improvement of enhancing capacity and functions of the walking robot is an important research issue.According to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is proposed.The proposed robot can be used for both a biped and a quadruped walking robot.The kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are optimized.The results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,respectively.Based on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk process.Besides laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.

Motion Error Compensation of Multi-legged Walking Robots

Existing errors in the structure and kinematic parameters of multi-legged walking robots,the motion trajectory of robot will diverge from the ideal sports requirements in movement.Since the existing error compensation is usually used for control compensation of manipulator arm,the error compensation of multi-legged robots has seldom been explored.In order to reduce the kinematic error of robots,a motion error compensation method based on the feedforward for multi-legged mobile robots is proposed to improve motion precision of a mobile robot.The locus error of a robot body is measured,when robot moves along a given track.Error of driven joint variables is obtained by error calculation model in terms of the locus error of robot body.Error value is used to compensate driven joint variables and modify control model of robot,which can drive the robots following control model modified.The model of the relation between robot＇s locus errors and kinematic variables errors is set up to achieve the kinematic error compensation.On the basis of the inverse kinematics of a multi-legged walking robot,the relation between error of the motion trajectory and driven joint variables of robots is discussed.Moreover,the equation set is obtained,which expresses relation among error of driven joint variables,structure parameters and error of robot＇s locus.Take MiniQuad as an example,when the robot MiniQuad moves following beeline tread,motion error compensation is studied.The actual locus errors of the robot body are measured before and after compensation in the test.According to the test,variations of the actual coordinate value of the robot centroid in x-direction and z-direction are reduced more than one time.The kinematic errors of robot body are reduced effectively by the use of the motion error compensation method based on the feedforward.

Retrospective study of effect of whole-body vibration training on balance and walking function in stroke patients

BACKGROUND Dysfunction in stroke patients has been a problem that we committed to solve and explore.Physical therapy has some effect to regain strength,balance,and coordination.However,it is not a complete cure,so we are trying to find more effective treatments.AIM To observe the effect of whole-body vibration training(WVT)on the recovery of balance and walking function in stroke patients,which could provide us some useful evidence for planning rehabilitation.METHODS The clinical data of 130 stroke participants who underwent conventional rehabilitation treatment in our hospital from January 2019 to August 2020 were retrospectively analyzed.The participants were divided into whole-body vibration training(WVT)group and non-WVT(NWVT)group according to whether they were given WVT.In the WVT group,routine rehabilitation therapy was combined with WVT by the Galileo Med L Plus vibration trainer at a frequency of 20 Hz and a vibration amplitude of 0+ACY-plusmn+ADs-5.2 mm,and in the NWVT group,routine rehabilitation therapy only was provided.The treatment course of the two groups was 4 wk.Before and after treatment,the Berg balance scale(BBS),3 m timed up-and-go test(TUGT),the maximum walking speed test(MWS),and upper limb functional reaching(FR)test were performed.RESULTS After 4 wk training,in both groups,the BBS score and the FR distance respectively increased to a certain amount(WVT=46.08±3.41 vs NWVT=40.22±3.75;WVT=20.48±2.23 vs NWVT=16.60±2.82),with P<0.05.Furthermore,in the WVT group,both BBS score and FR distance(BBS:18.32±2.18;FR:10.00±0.92)increased more than that in the NWVT group(BBS:13.29±1.66;FR:6.16±0.95),with P<0.05.Meanwhile,in both groups,the TUGT and the MWS were improved after training(WVT=32.64±3.81 vs NWVT=39.56±3.68;WVT=12.73±2.26 vs NWVT=15.04±2.27,respectively),with P<0.05.The change in the WVT group(TUGT:17.49±1.88;MWS:6.79±0.81)was greater than that in the NWVT group(TUGT:10.76±1.42;MWS:4.84±0.58),with P<0.05.CONCLUSION The WVT could effectively improve the balance and walking function in stroke patients,which may be good for improving their quality of life.

Planning and Control of COP-Switch-Based Planar Biped Walking

Efficient walking is one of the main goals of researches on biped robots. A feasible way is to translate the understanding from human walking into robot walking, for example, an artificial control approach on a human like walking structure. In this paper, a walking pattern based on Center of Pressure （COP） switched and modeled after human walking is introduced firstly. Then, a parameterization method for the proposed walking gait is presented. In view of the complication, a multi-space planning method which divides the whole planning task into three sub-spaces, including simplified model space, work space and joint space, is proposed. Furthermore, a finite-state-based control method is also developed to implement the proposed walking pattern. The state switches of this method are driven by sensor events. For convincing verification, a 2D simulation system with a 9-1ink planar biped robot is developed. The simulation results exhibit an efficient walking gait.

Comparison of walking quality variables between incomplete spinal cord injury patients and healthy subjects by using a footscan plantar pressure system

The main goal of spinal cord rehabilitation is to restore walking ability and improve walking quality after spinal cord injury(SCI). The spatiotemporal parameters of walking and the parameters of plantar pressure can be obtained using a plantar pressure analysis system. Previous studies have reported step asymmetry in patients with bilateral SCI. However, the asymmetry of other parameters in patients with SCI has not been reported. This was a prospective, cross-sectional study, which included 23 patients with SCI, aged 48.1 ± 14.5 years, and 28 healthy subjects, aged 47.1 ± 9.8 years. All subjects underwent bare foot walking on a plantar pressure measurement device to measure walking speed and spatiotemporal parameters. Compared with healthy subjects, SCI patients had slower walking speed, longer stride time and stance time, larger stance phase percentage, and shorter stride length. The peak pressures under the metatarsal heads and toe were lower in SCI patients than in healthy subjects. In the heel, regional impulse and the contact area percentage in SCI patients were higher than those in healthy subjects. The symmetry indexes of stance time, step length, maximum force, impulse and contact area were increased in SCI patients, indicating a decline in symmetry. The results confirm that the gait quality, including spatiotemporal variables and plantar pressure parameters, and symmetry index were lower in SCI patients compared with healthy subjects. Plantar pressure parameters and symmetry index could be sensitive quantitative parameters to improve gait quality of SCI patients. The protocols were approved by the Clinical Research Ethics Committee of Shengjing Hospital of China Medical University(approval No. 2015 PS54 J) on August 13, 2015. This trial was registered in the ISRCTN Registry(ISRCTN42544587) on August 22, 2018. Protocol version: 1.0.

Adjustable Mechanism for Walking Robots with Minimum Number of Actuators

Recent literature on walking robots deals predominantly with multi-degrees-of-freedom leg mechanisms and machines capable of adopting several gaits.This paper explores the other end of the spectrum suggesting mechanisms derived from a four bar coupler curve for a one degree of freedom walking robot.Simulation of the walk indicates that body of the robot is able to move with low variation in velocity.The best strategy for changing the gait to enable the robot to walk over obstacles and the effect of change in length of different links are explored to open up the possibility of a two degree of freedom walking robot with the capability of changing its gait,suitable as a low cost unit for several applications.Such rugged units would permit the use of an IC engine as the primary source of power and could be of utility in installations where electronics may not be functional.In simple walking machines the foot of a leg is usually required to trace a D shaped curve with respect to the chassis.In this paper we begin with a Hoecken mechanism capable of tracing such a curve.The foot is required to move parallel to itself and the same could be achieved using a six or eight link mechanism.A few such devices have been synthesized in this paper and their motion properties compared.The study also covers the possibility of providing adjustments to vary the step length and height of the foot＇s movement.

Surgical intervention combined with weight-bearing walking training improves neurological recoveries in 320 patients with clinically complete spinal cord injury:a prospective self-controlled study

Although a large number of trials in the SCI field have been conducted,few proven gains have been realized for patients.In the present study,we determined the efficacy of a novel combination treatment involving surgical intervention and long-term weight-bearing walking training in spinal cord injury(SCI)subjects clinically diagnosed as complete or American Spinal Injury Association Impairment Scale(AIS)Class A(AIS-A).A total of 320 clinically complete SCI subjects(271 male and 49 female),aged 16–60 years,received early(≤7 days,n=201)or delayed(8–30 days,n=119)surgical interventions to reduce intraspinal or intramedullary pressure.Fifteen days post-surgery,all subjects received a weight-bearing walking training with the“Kunming Locomotion Training Program(KLTP)”for a duration of 6 months.The neurological deficit and recovery were assessed using the AIS scale and a 10-point Kunming Locomotor Scale(KLS).We found that surgical intervention significantly improved AIS scores measured at 15 days post-surgery as compared to the pre-surgery baseline scores.Significant improvement of AIS scores was detected at 3 and 6 months and the KLS further showed significant improvements between all pair-wise comparisons of time points of 15 days,3 or 6 months indicating continued improvement in walking scores during the 6-month period.In conclusion,combining surgical intervention within 1 month post-injury and weight-bearing locomotor training promoted continued and statistically significant neurological recoveries in subjects with clinically complete SCI,which generally shows little clinical recovery within the first year after injury and most are permanently disabled.This study was approved by the Science and Research Committee of Kunming General Hospital of PLA and Kunming Tongren Hospital,China and registered at ClinicalTrials.gov(Identifier:NCT04034108)on July 26,2019.

The experimental study on the contact process of passive walking

The passive dynamic walking is a new concept of biped walking. Researchers have been working on this area with both theoretical analysis and experimental analysis ever since McGeer. This paper presents our compass-like pas- sive walking model with a new set of testing system. Two gyroscopes are used for measuring the angles of two legs, and ten FlexiForce sensors are used for measuring the con- tact forces on the feet. We got the experimental data on the passive walking process with the validated testing system. A great emphasis was put on the contact process between the feet and the slope. The contact process of the stance leg was divided into four sections, and differences between the real testing contact process and the classic analytical contact process with no bouncing and slipping were summarized

Walking pace and the risk of stroke:A meta-analysis of prospective cohort studies

Purpose:The extent to which walking pace is associated with a reduced risk for stroke remains unclear.This study examined the association between walking pace and stroke risk based on prospective cohort studies.Methods:Databases of PubMed,EMBASE,Web of Science,Scopus,and China National Knowledge Internet were searched from the inception dates to January 31,2019,for prospective cohort studies focusing on walking pace and risk of stroke in adults.Two reviewers independently extracted data and assessed the quality of the studies.The dependent measure was stroke incidence.Using random-effects models,a metaanalysis was performed to estimate the overall relative risks(RR)of stroke incidence and 95%confidence intervals(CIs)for the individuals with the fastest walking paces vs.individuals with the slowest walking paces.A dose-response relationship was also examined.Results:After screening 1294 titles/abstracts and 14 full-text studies identified in the search,7 studies(from 8 cohorts)were included in the metaanalysis.The 7 studies included a total of 135,645 participants(95.2%women;mean age 63.6 years)and 2229 stroke events(median follow-up time=8.0 years).Compared to individuals in the slowest walking-pace category(median=1.6 km/h),individuals in the fastest walking-pace category(median=5.6 km/h)had a 44%lower risk of stroke(pooled RR=0.56,95%CI:0.48-0.65).There was also a linear dose-response relationship(RR=0.87;95%CI:0.83-0.91),with the risk of stroke decreased by 13%for every 1 km/h increment in baseline walking pace.We observed similar results across walking-pace assessment,type of stroke ascertainment,stroke subtypes,sex,sample size,and duration of follow-up.Conclusion:Findings from this meta-analysis indicate that walking pace is inversely associated with the risk of stroke.

A novel explosion-proof walking system: Twin dual-motor drive tracked units for coal mine rescue robots

A new explosion-proof walking system was designed for the coal mine rescue robot(CMRR) by optimizing the mechanical structure and control algorithm. The mechanical structure innovation lies mainly in the dual-motor drive tracked unit used, which showed high dynamic performance compared with the conventional tracked unit. The control algorithm, developed based on decision trees and neural networking, facilitates autonomous switching between "Velocity-driven Mode" and "Torquedriven Mode". To verify the feasibility and effectiveness of the control strategy, we built a self-designed test platform and used it to debug the control program; we then made a robot prototype and conducted further experiments on single-step, ramp, and rubble terrains. The results show that the proposed walking system has excellent dynamic performance and the control strategy is very efficient, suggesting that a robot with this type of explosion-proof walking system can be successfully applied in Chinese coal mines.

The effects of total ankle replacement on ankle joint mechanics during walking

Background:End-stage ankle arthritis impairs joint function and patients' mobility.Total ankle replacement is a surgical procedure to treat severe ankle arthritis.Salto Talaris Anatomic Ankle^(TM)(STAA) was designed to mimic the normal ankle anatomy and flexion/extension of the ankle movement.The purpose of this study was to examine the effect of an STAA ankle replacement on ankle joint function and mechanics during gait.Methods:Five patients with end-stage unilateral ankle arthritis were recruited.Patients performed level walking in a laboratory setting on 2occasions,prior to and 3 months after the STAA ankle surgeries.American Orthopedic Foot and Ankle Society(AOFAS) hindfoot score was obtained.A 12-camera motion capture system was used to perform walking analysis.Gait temporo-spatial parameters and ankle joint mechanics were evaluated.Paired Student's t tests and non-parametric Wilcoxon matched tests were performed to examine the differences in biomechanical variables between the pre-and post-surgery walking conditions.Results:Compared to the pre-surgical condition,at 3 months of post-STAA surgery,patients experienced greater improvement in AOFAS hindfoot score(p = 0.0001);the STAA ankle demonstrated a 31% increase in ankle joint excursion(p = 0.045),a 22% increase in ankle plantarflexor moment(p = 0.075),a 60% increase in ankle power absorption(p = 0.023),and a 68% increase in ankle power production(p = 0.039).Patients also demonstrated a 26% increase in walking speed(p = 0.005),a 20% increase in stride length(p = 0.013),a 15% decrease in double support time(p = 0.043),and a 5% decrease in total stance time(p = 0.055).Conclusion:Three months after surgeries,the STAA patients experienced improvements in ankle function and gait parameters.The STAA ankle demonstrated improved ankle mechanics during daily activities such as walking.

Walking of spider on water surface studied from its leg shadows

Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. The three-dimensional trajectories and the supporting forces of water spider legs during walking forward were achieved. Results showed that the leg movement could be divided into three phases： slap, stroke, and retrieve. Employing an effective strategy to improving walking efficiency, the sculling legs supported most of its body weight while other legs were lifted to reduce the lateral water resistance, which was similar to the strategy of water striders. These findings could help guiding the design of water walking robots with high efficiency.

Stability and control of dynamic walking for a five-link planar biped robot with feet

During dynamic walking of biped robots, the underactuated rotating degree of freedom （DOF） emerges between the support foot and the ground, which makes the biped model hybrid and dimension-variant. This paper addresses the asymptotic orbit stability for dimension-variant hybrid systems （DVHS）. Based on the generalized Poincare map, the stability criterion for DVHS is also presented, and the result is then used to study dynamic walking for a five-link planar biped robot with feet. Time-invariant gait planning and nonlinear control strategy for dynamic walking with fiat feet is also introduced. Simulation results indicate that an asymptotically stable limit cycle of dynamic walking is achieved by the proposed method.

Six-minute walking test performance is associated with survival in cirrhotic patients

BACKGROUND Patients with cirrhosis are at risk of cirrhotic cardiomyopathy,with resulting cardiac dysfunction and exercise limitations.Six minute walking test(6MWT)assesses functional status and predicts morbidity and mortality in cardiopulmonary diseases.AIM To determine if it associates with mortality by analyzing 6MWT performance in patients with liver cirrhosis.METHODS A cohort of 106 cirrhotic patients was evaluated in the outpatient setting with echocardiogram and 6MWT and follow up for one year to document hepatic decompensation and mortality.The distance in meters was recorded at the end of 6 min(6MWD).RESULTS This cohort had a mean age of 51 years and 56%male;patients were staged as Child A in 21.7%,B 66%and C 12.3%.Walk distance inversely correlated with Child scores,and was significantly reduced as Child stages progresses.Patients who died(10.4%)showed shorter mean 6MWD(P=0.006).Low 6MWD was an independent predictor of mortality(P=0.01).CONCLUSION 6MWT is a noninvasive inexpensive test whose result is related to Child scores and mortality.It is useful to identify patients with liver cirrhosis at high risk of mortality for closer monitoring and potential early intervention.

Impactless biped walking on a slope

Walking without impacts has been considered in dynamics as a motion/force control problem. In order to avoid impacts, an approach for both the specified motion of the biped and its ground reaction forces was presented yielding a combined motion and force control problem. As an application, a walker on a horizontal plane has been considered. In this paper, it is shown how the control of the ground reaction forces and the energy consumption depend on the gradient of a slope. The biped dynamics and the constraints within the biped system and on the ground are discussed. A motion control synthesis is developed using the inverse dynamics principle proven to be most efficient for human walking research, too. The impactless walking with controlled legs is illustrated by a seven-link biped. The ＂flying＂ biped has nine degrees of freedom, with six control inputs. During locomotion, the standing leg has three scleronomic constraints, and the trunk has three rheonomic constraints. However, there are three rheonomic constraints for the prescribed leg motion or three scleronomic constraints for reaction forces of the trailing leg, respectively. The nominal control action for impactless walking can be precomputed and stored. The model proposed allows the investigation of several problems： uphill and downhill walking, optimization of step length,stiction of the feet on the slope and many more. All these findings are also of interest in biomechanics. C 2013 The Chinese Society of Theoretical and Applied Mechanics. [doi：10.1063/2.1301302]