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With the development of society, Gait recognition, as an emerging biometric identification technology, has been paid more and more attention for its unique advantages of non-aggression, uniqueness, remote identification, easy to collect, and difficult to fake and hide. In this article, the gait and the recognition of the age range are combined together. A method of extracting gait features based on...
In this paper, Selective Harmonic Mitigation (SHM) and Selective Harmonic Elimination (SHE) modulation techniques are combined to generate the appropriated firing pulses for a 4-leg 3-Level Neutral Point Clamped (NPC) inverter. SHM modulation technique is applied to the phase legs in order to get a desired modulation index (ma) and to mitigate the lower order odd non-triplen harmonics (5th, 7th, …)...
This paper analyses periodic gaits of multi-legged locomotion systems. The joint signals are studied in the Fourier domain, namely from the point of view of its reproducibility through low-pass actuators. The influence of several parameters is also considered and their critical values are investigated.
An on-line gait synthesis scheme for a bipedal walking robot is proposed. To realize efficient and human-like gait, MTi sensors were mounted on the lower limb of human subject to acquire kinematics information that can be integrated to the angular changes of hip and knee joints during walking. The time series angles were normalized and then sampled by cubic spline interpolation. By employing discrete-time...
Turning gait is a basic motion for humanoid robots. In this article a model free approach is presented and our emphasis is how to make robot's “turn-in-place” motion more stable and faster. In this regard we use Genetic algorithm to optimize produced signals by Fourier Series (FS) which controls joint's angels. We show the effectiveness of the proposed method through simulation and experimental results.
This paper describes a method of generating a stable walking trajectory for a biped humanoid robot. We design a desired ZMP trajectory by using a Fourier series, which has finite or infinite summation of sine and cosine functions, and calculating the coefficients of the Fourier series. And then, an analytic center of gravity (CoG) trajectory solution to the desired zero moment point (ZMP) trajectory...
Bipedal locomotion has good obstacle avoidance properties. A robot with human appearance has advantages in human-robot communication. However, walking control is difficult due to the complex robot dynamics involved. Stable reference generation is significant in walking control. The Linear Inverted Pendulum Model (LIPM) and the Zero Moment Point (ZMP) criterion are applied in a number of studies for...
Aiming to real easy application in several quadruped robot platforms, this paper introduces a new method of modeling central pattern generators (CPG) to control quadruped locomotion. Not only can this new model generate all the primary gaits of quadrupeds stably with limit cycle effect, but it also has the ability of tuning the periodic outputs with arbitrary waveforms. The core idea is to combine...
Bipedal locomotion is one of the most challenging problems in control, artificial intelligence, mechanics and other related fields. In this article a model free approach with emphasis on making robot's walking more stable and faster is presented. In this regard we use particle swarm optimization (PSO) to optimize the signals produced by truncated Fourier series (TFS) which control joints' angels....
Humanoid research has made notable progress during the past 25 years. However, currently most humanoids use the ZMP (zero moment point) for control of bipedal locomotion, which requires precise modeling and actuation with high control gains. On the contrary, researchers do not rely on such precise modeling and actuation. In this paper we have tried to introduce a novel method for the evolution of...
The control of a biped humanoid is a challenging task due to the hard-to-stabilize dynamics. Walking reference trajectory generation is a key problem. Linear Inverted Pendulum Model (LIPM) and Zero Moment Point (ZMP) Criterion-based approaches in stable walking reference generation are reported. In these methods, generally, the ZMP reference during a stepping motion is kept fixed in the middle of...
A ground angle estimation technique for use on ankle-foot-orthosis AFO, during gait is proposed. Strain gauge sensors were mounted on a foot orthosis in order to give information about strain in the sagittal plane. The ankle angle of the orthosis was fixed. Strain characteristics were therefore changed when walking on slopes. It was investigated if strain information could be used for detection of...
This article proposes a new hybrid methodology, together with an associated series of experiments employing this methodology, for an evolutionary gait generator that uses trigonometric truncated Fourier series formulations with coefficients optimized by a Genetic Algorithm. The Fourier series is used to model joint angle trajectories of a simulated humanoid robot with 25 degrees of freedom. The humanoid...
This paper presents three basic bipedal walking gait adjustment modes: stride-frequency adjustment, step-length adjustment and biped lower extremities' pattern adjustment. All the adjustment modes are based on the simple Fourier series formulation named as Truncated Fourier Series (TFS) model newly proposed as a walking pattern generator. Making use of these three gait adjustment modes, bipedal walking...
Humanoid robotics attracted the attention of many researchers in the past 35 years. The motivation of research is the suitability of the biped structure for tasks in the human environment. The control of a biped humanoid is a challenging task due to the hard-to-stabilize dynamics. Walking reference trajectory generation is one of the key problems. The zero moment point (ZMP) criterion is widely employed...
This paper presents a method for optimally generating stable bipedal walking gaits, based on a truncated Fourier series formulation with coefficients tuned by genetic algorithm. It also provides a way to adjust the stride-frequency, step-length or walking pattern in real-time. The proposed approach to gait synthesis is not limited by the robot kinematic structure and can be used to satisfy various...
Humanoid robotics attracted the attention of many researchers in the past 35 years. The motivation of research is the suitability of the biped structure for tasks in the human environment. The control of a biped humanoid is a challenging task due to the hard-to-stabilize dynamics. Walking reference trajectory generation is a key problem. A criterion used for the reference generation is that the reference...
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