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Energetic walking gaits studied by a simple actuated inverted pendulum model
Kang An,Yingyuan Liu,Yiran Li,Yunxia Zhang,Chengju Liu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.5
The mechanical structure and the joint torques configuration are the important parts in the biped robot design. Meanwhile, different walking speed and step length should be chosen to achieve efficient gait according to different need of walking environment. Therefore, this paper investigates the energetic walking gaits using a simple actuated inverted pendulum model. Joint torques and push-off impulse are both added in the model. The walking gaits with different joint torques configuration and with different combination of walking speeds and step lengths are analyzed. The results show that hip velocity direction is changed by the push-off impulse just before the heelstrike, which reduces the energy consumption of each step. The walking gait with minimal energy consumption is the walking pattern only with push-off, the energy cost of which is 1/4 of the walking pattern only with joint torque during the swing phase. The cost of transport (COT) and the push-off impulse of the walking gait is increasing with the increase of walking speed and step length. Using same value of push-off impulse, the walking with long step length and slow speed is more efficient. The paper can provide suggestions for designing advanced legged robot systems with high energy efficiency and various gaits. For example, the consideration of push-off mechanism can be used in the biped robots design.
2 족 로봇을 위한 선형 역진자 모델 기반의 토크 효율적인 걸음새 생성
신혁기,김병국 제어로봇시스템학회 2009 제어로봇시스템학회 국내학술대회 논문집 Vol.2009 No.9
This paper deals with walking reference trajectory generation techniques that is a key problem for stable locomotion of biped robots. In most studies based on the Linear Inverted Pendulum Model (LIPM) that widely employed in the full actuated-biped robot walk, the Zero-Moment-Point (ZMP) reference during a single-support phase is kept fixed in the center of the sole of the supporting foot. This approach makes the robot walk with the most stable condition but lacks naturalness and efficiency, in that, the ZMP in the human walk moves on the foot contact area. This paper propose a torque-efficient reference trajectory generation algorithm that ZMP references which move on the stable region in contact polygon, to minimize the input torques for all joints of a 12 DOF biped robot. Simulation results indicate that the variable ZMP references result in more torque-efficient gait.
스프링의 탄성력으로 보행 효율 향상에 기여하는 디바이스 설계 및 웨어러블 로봇에서의 적용 방안
송은석(EunSeok Song),이대호(DaeHo Lee),공경철(Kyoungchul Kong) 제어로봇시스템학회 2021 제어·로봇·시스템학회 논문지 Vol.27 No.3
The dynamics arising from the foot-ground interaction plays an important role in human gait. Thus, it is imperative to fabricate an appropriate foot module for a powered exoskeleton to improve its performance. In this paper, a new design for shoes that effectively utilize the forefoot dynamics is described. This new design has metatarsophalangeal (MTP) joints with embedded torsion springs that connect the forefoot with the rest of the foot. Prototypes of these shoes resembling common sandals were produced via 3D printing. Torsion springs can store energy until the occurrence of toe-off in the gait cycle and then release energy till the termination of toe-off, which makes walking possible with less power consumption. The proper use of this toe-off force can lead to a more natural and effective gait for the wearers of powered exoskeletons. The ground reaction forces were measured to analyze if the new design could indeed increase the toe-off force. Surface electromyography (sEMG) sensors were used to measure the muscle activity to compare the relative muscle fatigue for the cases with and without the newly proposed design. Experimental results showed that the springs in MTP joints reduced the muscle fatigue by 4% and they enabled an increase in the supporting force by 10% when walking on a flat ground. Experiments conducted for running and climbing stairs showed a nearly 30% increase in the supporting force and a 30% decrease in muscle fatigue, indicating a significant improvement. The forefeet or MTP joints were more actively engaged during running or climbing stairs and the spring had enough chance to play its role. Further research should focus on the verification of the design by incorporating it into wearable robot.
Kang An,Chuanjiang Li,Zuhua Fang,Chengju Liu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4
The selection of walking gait for biped robots depends on the requirement of walking environment. Walking with different situations of walking speeds and step lengths, the gait strategies are different. In this paper, we study the energetically optimal walking gait strategies under the different walking situations using a simple biped walking model with dynamic optimization method. The walking model with mass legs and three actuations, which is designed upon Srinivasan’s model, is built for the purpose of the paper. Dynamic optimization is used for a free search with minimal constraints. The analysis of the COT of the optimal gaits and its two components COT swing and COT push-off show that the COT is increasing with the increase of the walking speed. For a certain walking speed, the minimal value of COT can be found with a corresponding step length. According to the joint torques output strategies, we discover four gait patterns including two typical walking gaits patterns that the hip torque impulse is only at the beginning or at the end of the swing phase, respectively, and two other new transitional gait patterns.
Kim, On-Yoo,Shin, Yoon-Kyum,Yoon, Young Kwon,Ko, Eu Jeong,Cho, Sung-Rae Korean Academy of Rehabilitation Medicine 2015 Annals of Rehabilitation Medicine Vol.39 No.1
<P><B>Objective</B></P><P>To investigate the effect of treadmill walking exercise as a treatment method to improve gait efficiency in adults with cerebral palsy (CP) and to determine gait efficiency during overground walking after the treadmill walking exercise.</P><P><B>Methods</B></P><P>Fourteen adults with CP were recruited in the experimental group of treadmill walking exercise. A control group of 7 adults with CP who attended conventional physical therapy were also recruited. The treadmill walking exercise protocol consisted of 3-5 training sessions per week for 1-2 months (total 20 sessions). Gait distance, velocity, VO<SUB>2</SUB>, VCO<SUB>2</SUB>, O<SUB>2</SUB> rate (mL/kg·min), and O<SUB>2</SUB> cost (mL/kg·m) were assessed at the beginning and at the end of the treadmill walking exercise. The parameters were measured by KB1-C oximeter.</P><P><B>Results</B></P><P>After the treadmill walking exercise, gait distance during overground walking up to 6 minutes significantly increased from 151.29±91.79 to 193.93±79.01 m, and gait velocity increased from 28.09±14.29 to 33.49±12.69 m/min (p<0.05). Energy efficiency evaluated by O<SUB>2</SUB> cost during overground walking significantly improved from 0.56±0.36 to 0.41±0.18 mL/kg·m (p<0.05), whereas O<SUB>2</SUB> rate did not improve significantly after the treadmill walking exercise. On the other hand, gait velocity and O<SUB>2</SUB> cost during overground walking were not significantly changed in the control group.</P><P><B>Conclusion</B></P><P>Treadmill walking exercise improved the gait efficiency by decreased energy expenditure during overground walking in adults with CP. Therefore, treadmill walking exercise can be an important method for gait training in adults with CP who have higher energy expenditure.</P>
하지 착용형 외골격 로봇의 효율적 보행패턴 생성 및 에너지 효율성 검증
김완수(Wan Soo Kim),이승훈(Seung Hoon Lee),유재관(Jae Kwan Ryu),백주현(Joo Hyun Baek),김동환(Dong Whan Kim),한정수(Jung Soo Han),한창수(Chang Soo Han) Korean Society for Precision Engineering 2012 한국정밀공학회지 Vol.29 No.3
The purpose of this study is to verify the energy efficiency of the integrated system combining human and a lower extremity exoskeleton robot when it is applied to the proposed gait pattern. Energy efficient gait pattern of the lower limb was proposed through leg function distribution during stance phase and the dynamic-manipulability ellipsoid (DME). To verify the feasibility and effect of the redefined gait trajectory, simulations and experiments were conducted under the conditions of walking on level ground and ascending and descending from a staircase. Experiments to calculate the metabolic cost of the human body with or without the assistance of the exoskeleton were conducted. The energy consumption of the lower extremity exoskeleton was assessed, with the aim of improving the efficiency of the integrated system.
신창록(Chang-Rok Shin),김장섭(Jang Seob Kim),박종현(Jong Hyeon Park),유홍희(Hong Hee Yoo) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
In this paper, the dependency of energy efficiency on the walking/running pattern and the walking/running period is analyzed though simulations of walk, trot and gallop. A quadruped animal has its own original features in the walking pattern and the walking period for adaptation to the environment. The robot model used in the simulations has three active joints and one passive spring-loaded joint at each leg, which is based on the actual quadruped robot, HUNTER (Hanyang UNiversity TEtrapod Robot), developed in the lab. Also included is the dependency of energy efficiency on the walking period in trot.