scholarly journals Generation of Inverted Locomotion Gait for Multi-Legged Robots Using a Spherical Magnet Joint and Adjustable Sleeve

2021 ◽  
Author(s):  
Harn Sison ◽  
Photchara Ratsamee ◽  
Manabu Higashida ◽  
Yuki Uranashi ◽  
Takemura Haruo
Keyword(s):  
Reaction Force ◽  
Steel Structures ◽  
Quadruped Robot ◽  
Legged Robots ◽  
Legged Robot ◽  
Hexapod Robot ◽  
Foot Placement ◽  
Predominant Type ◽  
Different Types ◽  
Tripod Gait

Abstract In this paper, we propose a design and an implementation of spherical magnet joint (SMJ) - based gait generation for inverted locomotion of multi-legged robots. A spherical permanent magnet is selected to generate a consistent attractive force for the robot to perform inverted locomotion under steel structures. Additionally, the tip of the robot's foot is designed as a ball-joint mechanism to give flexibility to the foot placement at any angle between the tip and surfaces. We also propose an adjustable sleeve mechanism to detach the tip of the foot during locomotion by creating a fulcrum point during the tilt and pull step. As a result, the reaction force can be reduced according to sleeve diameter. Experimental results show that the presented load decreased by 46% from direct pulling with the adjustable sleeve mechanism. For inverted locomotion, a quadruped robot and a hexapod robot were constructed to represent the predominant type of multi-legged robot. We integrated the SMJ and the adjustable sleeve on both robots and performed the inverted locomotion with a crawling gait, a trotting gait, a square gait, and a tripod gait. Our analysis demonstrates the characteristics of each gait in terms of velocity, stability, guaranteeing the versatility of our proposed SMJ, which can be applied to different types of legged robots.

scholarly journals Power Consumption Characteristics Research on Mobile System of Electrically Driven Large-Load-Ratio Six-Legged Robot

2021 ◽  
Author(s):  
Hong-Chao Zhuang ◽  
Ning Wang ◽  
Hai-Bo Gao ◽  
Zong-Quan Deng
Keyword(s):  
Power Consumption ◽  
Body Height ◽  
Load Ratio ◽  
Legged Robots ◽  
Duty Ratio ◽  
Legged Robot ◽  
Mobile System ◽  
Large Load ◽  
Average Power Consumption ◽  
Tripod Gait

Abstract To research the power consumption characteristics of mobile system of an electrically driven large-load-ratio six-legged robot with engineering capability is beneficial to speed up it toward practicability. Based on the configuration and walking modes of robot, the mathematical model of the power consumption of mobile system is set up. In view of the tripod gait is often selected for the six-legged robots, the simplified power consumption model of mobile system under the tripod gait is established by means of reducing the dimension of the robot's statically indeterminate problem and constructing the equal force distribution. Then, the power consumption of robot mobile system is solved under different working conditions. The variable tendencies of the power consumption of robot mobile system are respectively obtained with changes in the rotational angles of hip joint and knee joint, body height, and span. The articulated rotational zones and the ranges of body height and span are determined under the lowest power consumption. According to the walking experiments of prototype, the variable tendencies of the average power consumption of robot mobile system are respectively acquired with changes in the duty ratio, body height, and span. Then, the feasibility and correctness of theory analysis are verified in the power consumption of robot mobile system. The proposed analysis method in this paper can provide a reference on the lower power research of the large-load-ratio multi-legged robots.

Dynamic Modeling and Control of the Hexapod Robot Using Matlab SimMechanics

2018 ◽  
Author(s):  
Sameh I. Beaber ◽  
Abdelrahman S. Zaghloul ◽  
Mohamed A. Kamel ◽  
Wessam M. Hussein
Keyword(s):  
Dynamic Modeling ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Legged Robot ◽  
Hexapod Robot ◽  
Modeling And Control ◽  
Robot Trajectory ◽  
Tripod Gait ◽  
Inverse Kinematic Analysis ◽  
And Control

This paper presents a detailed dynamic modeling of phantom ax12 six-legged robot using Matlab SimMechanics™. The direct and inverse kinematic analysis for each leg has been considered in order to develop an overall kinematic model of the robot. Trajectory of each leg is also considered for both swing and support phases when the robot walks with tripod gait in a straight path. Newton-Euler formulation has been utilized to determine the joint’s torque. These results were verified using SimMechanics™. Also, feet force distributions of the hexpaod are estimated via SimMechanics™, which is necessary for its control.

scholarly journals Design and Control of 7-DOF Omni-directional Hexapod Robot

2020 ◽  
Vol 11 (1) ◽  
pp. 80-89
Author(s):  
Marek Žák ◽  
Jaroslav Rozman ◽  
František V. Zbořil
Keyword(s):  
Degrees Of Freedom ◽  
Travel Speed ◽  
Legged Robots ◽  
Movement Speed ◽  
Legged Robot ◽  
Hexapod Robot ◽  
Unique Combination ◽  
Two Degrees Of Freedom ◽  
And Control ◽  
Omnidirectional Wheels

AbstractLegged robots have great potential to travel across various types of terrain. Their many degrees of freedom enable them to navigate through difficult terrains, narrow spaces or various obstacles and they can move even after losing a leg. However, legged robots mostly move quite slowly. This paper deals with the design and construction of an omni-directional seven degrees of freedom hexapod (i.e., six-legged) robot, which is equipped with omnidirectional wheels (two degrees of freedom are used, one for turning the wheel and one for the wheel itself) usable on flat terrain to increase travel speed and an additional coxa joint that makes the robot more robust when climbing inclined terrains. This unique combination of omnidirectional wheels and additional coxa joint makes the robot not only much faster but also more robust in rough terrains and allows the robot to ride inclined terrains up to 40 degrees and remain statically stable in slopes up to 50 degrees. The robot is controlled by a terrain adaptive movement controller which adjusts the movement speed and the gait of the robot according to terrain conditions.

scholarly journals Penerapan Algoritma Tripod Gait pada Robot Hexapod Menggunakan Arduino Mega128

2017 ◽  
Vol 7 (1) ◽  
pp. 37
Author(s):  
Andi Chairunnas
Keyword(s):  
Robot Control ◽  
Rotary Motion ◽  
Legged Robot ◽  
Hexapod Robot ◽  
Servo Motor ◽  
End Effector ◽  
Left Turn ◽  
Average Speed ◽  
Tripod Gait ◽  
Forward Kinematic

<em>The movement of the robot with wheels almost do not experience problems setting when road conditions tend to be flat or bypassed. However, problems arise when the condition of the streets where tend to be broken or wavy. With these problems legged robot is suitable for solving the problem. Legged robot itself is divided on several types, among others, two-legged robot (humanoid), four-legged robot (Quadpod), and a six-legged robot (Hexapod). This research will be discussed on how to build a Hexapod robot control at the system by applying the pattern step tripod gait on a Hexapod robot so that the accuracy of movement applied on a Hexapod Robot will produce the maximal movement patterns. In addition before determining the pattern step shall be applied forward gait tripod kinematic. Generally forward kinematic derived from around the corner join configuration so that the position of the end effector in Cartesian spaces (x, y) can determine the position of the corners on a servo motor from different corners of the position or angle of the servo value used to form the shape of the foot of each leg can determine the changes when the maneuver. It was only the application of pattern step tripod gait can be done, the robot can run well and constant can even generate some movement such as forward, backward, turn left, turn right. On testing the movement Forward in open areas and advanced on the Area Covered with an average speed of 5 cm/s, testing Motion backward on open areas and retreat in enclosed areas with an average speed of 4.32 cm/s, testing the rotary motion Right on open and Turning Right on Closed with an average speed of 13 degrees/minutes, testing the rotary motion of the left in the open and Turning left on Closed with an average speed of 12.85 degrees/sec The power needed, overall testing on areas of open and enclosed areas is 0.3 Volts with an overall duration of use 240.8 seconds.</em>

scholarly journals Terrain classification and adaptive locomotion for a hexapod robot Qingzhui

2021 ◽  
Author(s):  
Yue Zhao ◽  
Feng Gao ◽  
Qiao Sun ◽  
Yunpeng Yin
Keyword(s):  
Legged Robots ◽  
Measurement Unit ◽  
Support Vector ◽  
Hexapod Robot ◽  
Terrain Classification ◽  
Adaptive Locomotion ◽  
Joint Torques ◽  
Active Compliance ◽  
Outdoor Environments ◽  
The Stability

AbstractLegged robots have potential advantages in mobility compared with wheeled robots in outdoor environments. The knowledge of various ground properties and adaptive locomotion based on different surface materials plays an important role in improving the stability of legged robots. A terrain classification and adaptive locomotion method for a hexapod robot named Qingzhui is proposed in this paper. First, a force-based terrain classification method is suggested. Ground contact force is calculated by collecting joint torques and inertial measurement unit information. Ground substrates are classified with the feature vector extracted from the collected data using the support vector machine algorithm. Then, an adaptive locomotion on different ground properties is proposed. The dynamic alternating tripod trotting gait is developed to control the robot, and the parameters of active compliance control change with the terrain. Finally, the method is integrated on a hexapod robot and tested by real experiments. Our method is shown effective for the hexapod robot to walk on concrete, wood, grass, and foam. The strategies and experimental results can be a valuable reference for other legged robots applied in outdoor environments.

Background for New Revision of DNV-RP-C203 Fatigue Design of Offshore Steel Structures

2010 ◽  
Author(s):  
Inge Lotsberg
Keyword(s):  
Steel Structures ◽  
Electronic Version ◽  
Fatigue Assessment ◽  
Fatigue Design ◽  
Different Types ◽  
Background Material ◽  
Made In

The DNV-RP-C203 Fatigue Design of Offshore Steel Structures is being used by a number of different companies for fatigue assessment of different types of structures. This has resulted in questions to DNV about background for the different sections in the document. It is therefore important that the basis for this document is open to the industry. Quite a lot of the background material has also been published earlier at conferences and in journals. In some situations it has been found that the content can be improved to better suite the industry. The document is presented in an electronic version making revisions easy. Therefore it has been revised several times since the last official presentation of a revision in 2005. The present paper gives an overview of the most significant changes made in the document since the 2005 revision. Some of these changes are already included in the present version of DNV-RP-C203. The remaining changes will be included in a revision dated 2010.

scholarly journals Gait Programming for Multi-Legged Robot Climbing on Walls and Ceilings

2000 ◽  
Author(s):  
Jinwu Qian ◽  
Zhenbang Gong ◽  
Qixian Zhang
Keyword(s):  
Legged Robots ◽  
Legged Robot ◽  
Vertical Walls

Abstract Wall-climbing gait programming is one of the basic issues for the multi-legged robot working on vertical walls and ceilings. In this paper, the authors propose geometric measurements related to support patterns to describe the overturn-resistance capability for multi-legged robots climbing on vertical walls and on ceilings. Employing optimization approaches, optimal regular periodic wall gaits are computed for a six-legged robot climbing vertically or horizontally, and optimal ceiling gaits are also obtained. Comparisons are made for crab-type and insect-type leg-stroke layouts.

scholarly journals The Effect of slit-friction hybrid damper on the Performance of Dual System

2019 ◽  
Vol 13 (1) ◽  
pp. 271-280
Author(s):  
Azadeh Khoshkroodi ◽  
Hossein Parvini Sani
Keyword(s):  
Time History ◽  
Steel Structures ◽  
Repair Cost ◽  
Friction Dampers ◽  
History Analysis ◽  
Different Types ◽  
Moment Resisting ◽  
Hybrid Damper ◽  
Large Earthquakes ◽  
Different Levels

Aims: The aim of the present paper is to evaluate the behavior of slit friction hybrid dampers (SFHD) on steel structures. Therefore, the behavior moment resisting steel frames of structures in original stats and structures equipped with hybrid damper with two different types of behavior was analyzed and evaluated. Background: The recent study evaluated the combined effect of shear-friction dampers and slit dampers with measurements of non-uniform strips in seismic protection for different levels of energy. The recent study was carried out a about hybrid dampers, consisting of friction and split dampers in response to small and large earthquakes. Previous results have shown the ability of inactive hybrid systems in improving the reaction of structures to traditional lateral-systems. Kim and Shin showed that structures consisted of hybrid dampers needed less repair cost and time. Methods: Pushover and time history were carried out on original structures and structures equipped with dampers, in 5 and 10 stories structures. Results: Analysis about the probability of collapse showed about 30% and 84%. Conclusion: According to the result, by adding the SFHD, increased stiffness by 17% in retrofitted structures such as drift and displacement of roof decreases by 27% and 20% in push over analysis, respectively. Also, displacement in time history analysis up to 55% reduces in average. Also, the results of the IDA show that adding the SFHD to structures significantly increases by 55% the spectral acceleration capacity in structures.

scholarly journals Active foot placement control ensures stable gait: Effect of constraints on foot placement and ankle moments

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242215
Author(s):  
A. M. van Leeuwen ◽  
J. H. van Dieën ◽  
A. Daffertshofer ◽  
S. M. Bruijn
Keyword(s):  
Steady State ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Reaction Force ◽  
Stride Frequency ◽  
Tight Control ◽  
Foot Placement ◽  
Ankle Moment ◽  
Reaction Forces ◽  
Moment Control

Step-by-step foot placement control, relative to the center of mass (CoM) kinematic state, is generally considered a dominant mechanism for maintenance of gait stability. By adequate (mediolateral) positioning of the center of pressure with respect to the CoM, the ground reaction force generates a moment that prevents falling. In healthy individuals, foot placement is complemented mainly by ankle moment control ensuring stability. To evaluate possible compensatory relationships between step-by-step foot placement and complementary ankle moments, we investigated the degree of (active) foot placement control during steady-state walking, and under either foot placement-, or ankle moment constraints. Thirty healthy participants walked on a treadmill, while full-body kinematics, ground reaction forces and EMG activities were recorded. As a replication of earlier findings, we first showed step-by-step foot placement is associated with preceding CoM state and hip ab-/adductor activity during steady-state walking. Tight control of foot placement appears to be important at normal walking speed because there was a limited change in the degree of foot placement control despite the presence of a foot placement constraint. At slow speed, the degree of foot placement control decreased substantially, suggesting that tight control of foot placement is less essential when walking slowly. Step-by-step foot placement control was not tightened to compensate for constrained ankle moments. Instead compensation was achieved through increases in step width and stride frequency.

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