• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.8
• /
• pp.703-710
• /
• 2004

This paper presents discontinuous zigzag gait analysis for a newly modeled quadruped walking robot with an articulated spine which connects the front and rear parts of the body. An articulated spine walking robot can move easily from side to side, which is an important feature to guarantee a larger gait stability margin than that of a conventional single rigid-body walking robot. First, we suggest a kinematic modeling of an articulated spine robot which has new parameters such as a waist-joint angle, a rotate angle of a front and rear body and describe characteristics of gait using an articulated spine. Next, we compared the difference of walking motion of newly modeled robot with that of a single rigid-body robot and analyzed the gait of an articulated spine robot using new parameters. On the basis of above result, we proposed a best walking motion with maximum stability margin. To show the effectiveness of proposed gait planning by simulation, firstly the fastest walking motion is identified based on the maximum stride, because the longer the stride, the faster the walking speed. Next, the gait stability margin variation of an articulated spine robot is compared according to the allowable waist-joint angle.

• PNF and Movement
• /
• v.16 no.2
• /
• pp.195-205
• /
• 2018

Purpose: The purpose of this study was to demonstrate the effects of proprioceptive neuromuscular facilitation (PNF) stability techniques on walking speed, trunk stability, and balance in stroke patients. Methods: Ten stroke patients volunteered to participate in the study, and each of subjects was randomly assigned to either the stability technique (ST) group (n=5) or to the treadmill (TM) group (n=5). Each therapeutic exercise program was provided for 30 minutes a day, 5 days per week for 4 weeks. The ST group performed a PNF pattern combined with stabilizing reversal and rhythmic stabilization of the PNF stability technique. Walking speed (measured using a 10-meter walking test), trunk stability (TIS), and balance (BBS, FRT) were evaluated before and after training. All data were analyzed using SPSS version 18.0. The significance level for statistical inspection was set at 0.05. Results: Both groups showed improvements on the 10-meter walking test, the trunk impairment scale, the Berg balance scale, and the functional reaching test. Conclusion: PNF stability techniques are effective for improving trunk stability, balance, and walking speed in stroke patients. For stroke patients, PNF stability techniques are very useful and effective, including in clinical practice.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1780-1783
• /
• 2005

In this paper ZMP was considered in order to get a walking stability, so the gait in the stable domain was realized through putting the stability margin in the sole domain of a foot. It is assumed that the robot's legs have 12 joints to operate a open-loop drive and there was no external disturbance under walking phases, additionally, the robot is walking on the flat plane. It was observed that the robot's walking trajectory, locus of COM and ZMP after imposing the motion to each joint. For realizing the simulation considering ZMP and movement of mass center, it was checked if it is stable for the constraint robot model to walk in stability and the feasibility was estimated about its dynamic gait. Eventually it was shown that a constraint gait algorithm is able to realize. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.551-554
• /
• 2001

A necessity of remote control robots or various searching robots etc. that accomplish works given instead of human under long distance and extreme environment such as volcano, universe, deep-sea exploration and nuclear power plant etc. is increasing, and so the development and the research regarding these mobile robots are actively progressing. The wheel mobile robot or the track mobile robot have a sufficient energy efficiency under this en, but also have a lot of limits to accomplish works given which are caused from the restriction of mobile ability. Therefore, recently many researches for the walking robot with superior mobility and energy efficiency on the terrain, which is uneven or where obstacles, inclination and stairways exist, have been doing. The research for these walking robots is separated into fields of mechanism and control system, gait research, circumference environment and system condition recognition etc. greatly. It is a research field that the gait research among these is the centralist in actual implementation of walking robot unlike different mobile robots. A research field for gait of walking robot is classified into two parts according to the nature of the stability and the walking speed, static gait or dynamic gait. While the speed of a static gait is lower than that of a dynamic gait, a static gait which moves the robot to maintain a static stability guarantees a superior stability relatively. A dynamic gait, which make the robot walk controlling the instability caused by the gravity during the two leg supporting period and so maintaining the stability of the robot body spontaneously, is suitable for high speed walking but has a relatively low stability and a difficulty in implementation compared with a static gait. The quadruped walking robot has a strong point that can embody these gaits together. In this research, we will develope an autonomous quadruped robot with an asaptibility to the environment by selectry appropriate gait, element such as duty factor, stride, trajectory, etc.

• Proceedings of the KIEE Conference
• /
• 2004.05a
• /
• pp.138-140
• /
• 2004

This paper mainly deals with the dynamic walking of a biped robot. At first, in order to walk in various environments, it is desirable to adapt to such ground conditions with a suitable foot motion, and maintain the stability of the robot by a smooth hip motion. A method to plan a walking pattern consisting of a foot trajectory and a hip trajectory is presented. The effectiveness of the proposed method is illustrated by simulation results. Secondly, the paper brings forward a balance control technique based on off-line walking pattern with real-time modification. At last, the concept of Zero Moment Point (ZMP) is used to evaluate dynamic stability.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.1
• /
• pp.89-96
• /
• 2005

This paper is concerned with a balancing motion formulation and control of the ZMP (Zero Moment Point) for a biped-walking robot that has a prismatic balancing weight or a revolute balancing weight. The dynamic stability equation of a walking robot which have a prismatic balancing weight is conditionally linear but a walking robot's stability equation with a revolute balancing weight is nonlinear. For a stable gait, stabilization equations of a biped-walking robot are modeled as non-homogeneous second order differential equations for each balancing weight type, and a trajectory of balancing weight can be directly calculated with the FDM (Finite Difference Method) solution of the linearized differential equation. In this paper, the 3dimensional graphic simulator is developed to get and calculate the desired ZMP and the actual ZMP. The operating program is developed for a real biped-walking robot IWRⅢ. Walking of 4 steps will be simulated and experimented with a real biped-walking robot. This balancing system will be applied to a biped humanoid robot, which consist legs and upper body, as a future work.

• Proceedings of the KIEE Conference
• /
• 1998.11b
• /
• pp.546-548
• /
• 1998

This paper deals with ZMP trajectory generation in multi step walking of IWR-III(Inha Walking Robot) Biped Walking Robot. Biped walking is realized by combining 6-types of pre-defined steps and the actual ZMP can be used as a stability index of a robot. For the good tracking of actual ZMP, desired ZMP trajectory is generated during the whole walking time not for each step. Trajectory generation is performed considering velocities and accelerations of given via points using 5-th order polynomial interpolation method. As a result, balancing joints have a more smooth and continuous motion and actual ZMP has a better tracking ability. Numerical simulator is done by MATLAB to guarantee the walking of a robot satisfying the ZMP stability.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.42-42
• /
• 2000

This paper concerns an efficient aperiodic static crab walking algorithm for quadruped walking machine in rough terrain. In this algorithm, the requirements for forward stability margin and backward stability margin could be given differently in order to consider the slope of terrain and disturbances resulting from moving velocity. To restrict the searing regions for motion variables, such as moving distances until a leg is lifted or is placed, the standard leg transferring sequence is decided to be that of wave gaits. standard support pattern is also proposed that enables the quadruped to continue forward motion using the standard leg transferring sequence without falling into deadlock.

• Korean Journal of Applied Biomechanics
• /
• v.29 no.2
• /
• pp.79-88
• /
• 2019

Objective: The aim of this study was to determine the peak torques of the knee and ankle joint and local stability of the lower extremity's joints, and muscle activation patterns of the lower extremity's muscles between fallers and non-fallers in the elderly women during walking. Method: Four elderly women (age: $74.5{\pm}5.2yrs.$; height: $152.1{\pm}5.6cm$; mass: $55.3{\pm}5.4kg$; preference walking speed: $1.19{\pm}0.06m/s$) who experienced falls within six months since experiment had been conducted (falls group) and thirty-six subjects ($74.2{\pm}3.09yrs.$; height: $153.6{\pm}4.9cm$; mass: $56.7{\pm}6.4kg$; preference walking speed: $1.24{\pm}0.10m/s$) who had no experience in falls (non-falls group) within this periods participated in this study. They were measured torque peaks of the knee and ankle joint using a Human Norm and while they were walking on a treadmill at their natural pace, kinematic variables and EMG signals were collected with using a 3-D motion capture system and a wireless EMG system, respectively. Lyapunov Exponent (LyE) was determined to observe the dynamic local stability of the lower extremity's joints, and muscles activation and their co-contraction index were also analysed from EMG signals. Hypotheses between falls and non-falls group were tested using paired t-test and Mann-Whitey. Level of significance was set at p<.05. Results: Local dynamic stability in the adduction-abduction movement of the knee joint was significantly lower in falling group than non-falling group (p<.05). Conclusion: In conclusion, muscles which act on the abduction-adduction movement of the knee joint need to be strengthened to prevent from potential falls during walking. However, a small number of samples for fallers make it difficult to generalize the results of this study.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.35 no.7
• /
• pp.119-126
• /
• 2019

The active living of the elderly leads to improve their lives and enhance social networks. In the view of the active living, the walkability is an essential factor for the elderly's daily life. To support the active living, making age-friendly environment is important. Considering that the elderly mainly carry out activities through walking, making the age-friendly walking environment is a preliminary action. The existing studies applied various methods such as surveys by experts. In spite of the benefits in theirs, there is still a limitation that current walkability measurement methods did not incorporate the actual elderly's walking activity. Thus, the purposes of this study is to measure the elderly's walking quantitatively using a wearable sensor, and to investigate the feasibility of comparing several walking environments based on the data collected from the actual elderly's walking. To do this, experiment was conducted in four types environments with 22 senior subjects. The walkability was measured by walking stability represented quantitatively as Maximum Lyapunov Exponent (MaxLE). Through the experiment results, it was confirmed that the stability of the elderly walking was different according to the walking environment, which also meant that bodily responses (walking stability) is highly related to walkability. The results will provide an opportunity for the continuous diagnosis of walking environments, thereby enhancing the active living of the elderly.