Moving Control of Quadruped Hopping Robot Using Adaptive CPG Networks

This paper describes the moving control using the adaptive Central Pattern Generators (CPGs) including motor dynamic models for our developed quadruped hopping robot. The CPGs of each leg is interconnected with each other and by setting their coupling parameters can act as the flexible oscillators of each leg and adjust the hopping height of each leg to require stable hopping motion. The formation of the CPG networks are suitable not only to generate the continuous jumping motion but also can generate the moving motion in twodimensional, respectively. We also propose the reference height control system which including the maximum hopping height detector and Proportional Integral (PI)controller to achieve the reference jumping height. By using the proposed method, the hopping height of each leg can be control independently in order to make the posture of robot’s body incline ahead and move forward. We create MATLAB/Simulink model to conduct various types of experiments and confirmed the effectiveness of our proposed CPG model including the reference height control system to generate the stable moving performance while jumping continuously

Neuro-mechanical entrainment in a bipedal robotic walking platform

In this study, we investigated the use of van der Pol oscillators in a 4-dof embodied bipedal robotic platform for the purposes of planar walking. The oscillator controlled the hip and knee joints of the robot and was capable of generating waveforms with the correct frequency and phase so as to entrain with the mechanical system. Lowering its oscillation frequency resulted in an increase to the walking pace, indicating exploitation of the global natural dynamics. This is verified by its operation in absence of entrainment, where faster limb motion results in a slower overall walking pace

Neuro-mechanical entrainment in a bipedal robotic walking platform

In this study, we investigated the use of van der Pol oscillators in a 4-dof embodied bipedal robotic platform for the purposes of planar walking. The oscillator controlled the hip and knee joints of the robot and was capable of generating waveforms with the correct frequency and phase so as to entrain with the mechanical system. Lowering its oscillation frequency resulted in an increase to the walking pace, indicating exploitation of the global natural dynamics. This is verified by its operation in absence of entrainment, where faster limb motion results in a slower overall walking pace

Multiple chaotic central pattern generators with learning for legged locomotion and malfunction compensation

An originally chaotic system can be controlled into various periodic dynamics. When it is implemented into a legged robot's locomotion control as a central pattern generator (CPG), sophisticated gait patterns arise so that the robot can perform various walking behaviors. However, such a single chaotic CPG controller has difficulties dealing with leg malfunction. Specifically, in the scenarios presented here, its movement permanently deviates from the desired trajectory. To address this problem, we extend the single chaotic CPG to multiple CPGs with learning. The learning mechanism is based on a simulated annealing algorithm. In a normal situation, the CPGs synchronize and their dynamics are identical. With leg malfunction or disability, the CPGs lose synchronization leading to independent dynamics. In this case, the learning mechanism is applied to automatically adjust the remaining legs' oscillation frequencies so that the robot adapts its locomotion to deal with the malfunction. As a consequence, the trajectory produced by the multiple chaotic CPGs resembles the original trajectory far better than the one produced by only a single CPG. The performance of the system is evaluated first in a physical simulation of a quadruped as well as a hexapod robot and finally in a real six-legged walking machine called AMOSII. The experimental results presented here reveal that using multiple CPGs with learning is an effective approach for adaptive locomotion generation where, for instance, different body parts have to perform independent movements for malfunction compensation.Comment: 48 pages, 16 figures, Information Sciences 201

Legged locomotion over irregular terrains: State of the art of human and robot performance

Legged robotic technologies have moved out of the lab to operate in real environments, characterized by a wide variety of unpredictable irregularities and disturbances, all this in close proximity with humans. Demonstrating the ability of current robots to move robustly and reliably in these conditions is becoming essential to prove their safe operation. Here, we report an in-depth literature review aimed at verifying the existence of common or agreed protocols and metrics to test the performance of legged system in realistic environments. We primarily focused on three types of robotic technologies, i.e., hexapods, quadrupeds and bipeds. We also included a comprehensive overview on human locomotion studies, being it often considered the gold standard for performance, and one of the most important sources of bioinspiration for legged machines. We discovered that very few papers have rigorously studied robotic locomotion under irregular terrain conditions. On the contrary, numerous studies have addressed this problem on human gait, being nonetheless of highly heterogeneous nature in terms of experimental design. This lack of agreed methodology makes it challenging for the community to properly assess, compare and predict the performance of existing legged systems in real environments. On the one hand, this work provides a library of methods, metrics and experimental protocols, with a critical analysis on the limitations of the current approaches and future promising directions. On the other hand, it demonstrates the existence of an important lack of benchmarks in the literature, and the possibility of bridging different disciplines, e.g., the human and robotic, towards the definition of standardized procedure that will boost not only the scientific development of better bioinspired solutions, but also their market uptake

Brake Motion Control for Quadruped Hopping Robot by Using Reference Height Control System

In this paper, the generation of brake motion control for our developed quadruped hopping robot while moving on two dimensional spaces by jumping continuously is discussed. The braking motion method which is approached is by applying the reference height control system to create the differences of front leg and back leg while making moving performance and correct the body posture which has inclined to make the quadruped hopping robot jump vertically while braking performances. On the other hand, this approached method can be used as the collision-avoidance behavior for the quadruped hopping robot. The MATLAB/Simulink model is used in order to conduct the pattern generation of quadruped hopping robot. As the result, effectiveness of approach method is confirmed to generate brake motion control of quadruped hopping robot while making continuous jumping vertically. Copyright © 2013 Praise Worthy Prize S.r.l. - All rights reserve

Design And Development of Tripod Hopping Robot

In this paper, we discuss on the validity of using infrared ranging sensor instead of using ultrasonic ranging sensor for the developed tripod hopping robot. The infrared sensor is mounted on the shared platform and the real distance of infrared ranging sensor from the shared platform to the floor in both static and vertical jumping motion are measured. MATLAB&Simulink model including CPG networks is designed to evaluate the performance of infrared ranging sensor by converting the measurement data from infrared ranging sensor from Voltage to Distance by using function blocks. As the result, the jumping height for each hopping motion can be observed. In addition, the maximum height of the developed tripod hopping robot is also evaluated in order to identify the highest jumping capability. Therefore, MATLAB&Simulink model with maximum height detector system is designed without including the PI controller system. As the result, the effectiveness of the maximum height detector system for the developed tripod hopping robot is confirmed in order to evaluate the highest and stable jumping height

Moving Motion Control System On Developed Tripod Hopping Robot

This paper discussed on evaluation and validation of method in order to generate the moving motion control system of the developed tripod hopping robot. The proposed method to control the system is designed by using MATLAB&Simulink which consist of reference height control system and the networks of Central Pattern Generator (CPG) that can controlled the hopping height of each leg independently. By using this method, one of the legs of the tripod hopping robot is set to different value than the other leg in order to make the posture of hopping robot’s body incline ahead towards to the direction which it should move, respectively. As the result, the effectiveness of the approached method to generate moving motion of the hopping robot using CPG networks that including the reference height control system is confirmed while maintain the stability of developed tripod hopping robot from tumbled ahead