Four-legged Robot Research Articles

Plataforma de Emulación de Animales Cuadrúpedos: Cinemática de las Patas

En este trabajo se presenta un robot de cuatro patas que posee dos servomotores por pata (ocho en total), localizados en los hombros y codos en los cuartos delanteros y en las caderas y rodillas en los cuartos traseros. El diseño, construcción y programación de este robot, tiene como objetivo la emulación de animales cuadrúpedos. Esta plataforma robot, puede caminar de diferentes maneras para imitar tanto animales existentes como así también cuadrúpedos extintos. El robot puede caminar hacia delante y hacia atrás y además hacerlo con diferentes estrategias sin caerse.

Walking Pattern for Quadruped as Observer Robot

This paper explains about the walking patterns of quadruped robots. This robot was made to be an observer robot. Therefore, being slick in movement is the main feature that must be owned by this robot. As a four-legged robot, the movement (forward, backward, shift left, shift right, rotate) requires an algorithm to control the synchronization movements of each leg. This algorithm consists of several poses (including the body, as well as all legs) and if arranged in sequence it will form a certain pattern of movement. Each leg has 3 DOF. The pose of each leg is represented in the cartesian coordinates (x, y, z axis), while the movement of each joint is represented in angular. It has solved using the inverse kinematics formula which is useful for converting leg coordinates into angular for each leg joint. By defining the walking pattern, the robot can more easily controlled by the direction and speed of its movement.

Control of Four-legged Robot Using Pressure Sensor on Toe

Control of Four-legged Robot Using Pressure Sensor on Toe

Development of agricultural bionic four-legged robot: Effect of head movement adjustment on the stability of goats

The four-legged bionic robot for agriculture has been one of the hotspots in the field of robotics. The farmland environment is complex, and the balance requirement of quadruped bionic robot is higher. However, head adjustment is a key factor affecting the balance of quadruped animals. Based on this, this study takes the four-legged animal goat as an example to investigate the effect of goat head movement adjustment on the balance of goat. In this study, the head and neck of goats were simplified to a two-link model. The kinematics model was established by D-H method. MATLAB software was used to solve it. Origin software was used to draw the movement track of the center of mass of the head. The center of mass movement of the head is a quarter ellipse. Then, the goat walking experiments were carried out on the different slopes (0°, 5°, 10°, 15°, 20°, 25°, 30°, 35° and 40°). MATLAB software was used to fit the movement data of goat head. The movement of the center of mass of the goat's head corresponds to Fourier 6. The result is: the determination coefficient is 0.8629, and the mean variance is 0.019. When the slope gradient gradually increases, the volatility gradually increases and is cyclical. The results of this study verify the rationality of the four-legged bionic mechanism under various parameters and reveal the mechanism of goat walking with an appendage at the head. Keywords: bionic four-legged robot, slope, head, center of mass, trajectory, balance DOI: 10.25165/j.ijabe.20191204.4287 Citation: Zhang F, Wang Y F, Teng S, Zheng L M, Wang J J, Chen Z J. Development of agricultural bionic four-legged robot: Effect of head movement adjustment on the stability of goats. Int J Agric & Biol Eng, 2019; 12(4): 10–15.

Autonomous gait transition method for pacing four-legged robots

Autonomous gait transition method for pacing four-legged robots

A Four-legged Robot’s Soft Feet Structural Design and Walking Gait Generated from Inverse Kinematics

The conventional wheel is famous in the industrial mobile robot because it is simple to build and easy to control and to maneuver. On the other hand, the legged robot is complicated to control but has a high performance in locomotion like highly evolved legged-creatures. This research describes the four-legged robot design platform with the soft feet, which are made by silicone-material forming. The robot’s feet are implanted by the strain gauge sensor. The robot can percept the external force sensitively when its feet touch something. The research demonstrates the forward kinematics and inverse kinematics of a four-legged robot with three joints for each. The result has validated the kinematic equations by implementing them on the real dog-like pet robot. The robot walked with a pure walking gait and showed a sensing signal from the soft foot and ground contact.

Four-legged robot design and gait planning

This paper proposes a new type of hybrid leg mechanism based on a five-bar mechanism. The single leg has three degrees of freedom. The positive and negative solutions of the leg mechanism are analyzed theoretically and solved with MATLAB. The gait planning choose diagonal gait. ADAMS is used to verify the centroid displacement and foot displacement of each leg of the gait planning. This model is proposed based on series-parallel mechanism. The mechanism not only increases the movement space and improves the carrying capacity, but also has the advantages of simple control and flexible movement. This research lays a theoretical foundation for later experiments.

KINEMATIC AND JACOBIAN ANALYSIS APPROACH FOR THE FOUR-LEGGED ROBOT

This paper presents forward kinematics, inverse kinematics and Jacobian analysis of four-legged robot research. The kinematics analysis is the main problem of the legged robot. The four-legged robots are very complex more than wheeled robots. In this study,the four-legged robot of each leg calculates Denavit-Hartenberg (D-H) method,that is used for forward kinematics and the inverse is used the geometrical and mathematical methods.The Kinematic divided into two categories Forward Kinematic and Inverse Kinematics. The forward kinematic is calculated we knew the leg of endpoint position for the angles (θ1,θ2 and θ3 ). . Inverse kinematics is used to compute the joint angles which will achieve a desired position and orientation of the end-effector relative to the base frame. The Jacobian is one of the most important analyses for controlling smooth trajectory planning and execution in the derivation of the dynamic equation of robot motion.For calculation is used MATLAB software and robot modeling is used Simulink toolbox in MATLAB software. A program is obtained that calculate joint of angular velocity and angles to move from the desired position to target position. In this study are given different angular velocity and angle of the endpoint of the leg. The work mainly focuses on mechanical design, calculation of kinematic analysis, Jacobian function and experiment data of four-legged robots in MATLAB simulation.

Neuro-Activity-Based Dynamic Path Planner for 3-D Rough Terrain

This paper presents a natural mechanism of the human brain for generating a dynamic path planning in 3-D rough terrain. The proposed paper not only emphasizes the inner state process of the neuron but also the development process of the neurons in the brain. There are two algorithm processes in this proposed model, the forward transmission activity for constructing the neuron connections to find the possible way and the synaptic pruning activity with backward neuron transmission for finding the best pathway from current position to target position and reducing inefficient neuron with its synaptic connections. In order to respond and avoid the unpredictable obstacle, dynamic path planning is also considered in this proposed model. An integrated system for applying the proposed model in the real cases is also presented. In order to prove the effectiveness of the proposed model, we applied it in the pathway of a four-legged robot on rough terrain in both computer simulation and real cases. Unpredictable collision is also performed in those experiments. The model can find the best pathway and facilitate the safe movement of the robot. When the robot found an unpredictable collision, the path planner dynamically changed the pathway. The proposed path planning model is capable to be applied in further advance implementation.

A four-legged robot's soft feet structural design and walking gait generated from inverse kinematics

A four-legged robot's soft feet structural design and walking gait generated from inverse kinematics

Acquisition of Four-legged Running Robot Movement Policy Based on Reinforcement Learning to Move up a Slope

Acquisition of Four-legged Running Robot Movement Policy Based on Reinforcement Learning to Move up a Slope

Design and Fabrication of Four-legged Robot with 12-DOF

Design and Fabrication of Four-legged Robot with 12-DOF

Parameter optimization of a four-legged robot to improve motion trajectory accuracy using signal-to-noise ratio theory

When a multi-legged robot moves, the accuracy of robot movement can be affected by many mutually dependent noise factors such as errors during manufacture and assembly, the joint gap, and the deflection of links. In this paper, we present a parameter optimization method to improve motion trajectory accuracy. One important research objective is to discover parameter values which can be selected to make robot movements more accurate without having to improve the noise generating factors. Our method combines signal-to-noise ratio (SNR) theory with Taguchi technology. We use a four-legged robot-MiniQuad following a beeline tread as an example. Our proposed procedure consists of three stages. Stage 1: SNR theory is introduced to evaluate the impact of parameter change on the robot pose, by using the fluctuations in the robot's pose as the signal, and parameter fluctuations as the noise. Stage 2: A motion model for the robot's fluctuating pose was built. Stage 3: The maximization of "SNR" is used as an optimization object that is based on determining the parameters significance. Taguchi technology is used to realize the robot parameter optimization. For a group of optimized parameters, the body's trajectory fluctuation is minimized when the robot has the same amount of noise factors. Our experimental results of the four-legged robot show that our approach is useful and will aid further improvements for optimizing and designing parameters of multi-legged robots.

Penerapan Algoritma Tripod Gait pada Robot Hexapod Menggunakan Arduino Mega128

<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>

岩石把持グリッパを用いた 4 足歩行ロボットの開発

Robotic exploration in an extreme environment plays an increasingly important role. Such an environment is basically not easy for humans to access, and an on-site manned activity also carries a lot of risks. Thus, it is useful to utilize a mobile robot that can investigate and collect information of extreme environment. In this laboratory, we have proposed a rock climbing robot that moves while gripping the surface of the ground with grippers. By gripping the ground surface, it is possible to conduct a stable exploration activity even in irregular terrain with steep slope, where is difficult to travel with wheeled or trucked type robots. In this paper, the authers developed a spine-type gripper capable of gripping the rocky environment and a four-legged robot using the grippers. We also demonstrated the developed gripper and robot are useful for climbing rugged terrain with slope by experiments.

馬型4脚歩行ロボットのCPG設計

馬型4脚歩行ロボットのCPG設計

脚車輪ハイブリッド移動ロボットに関する研究

This report explains a constant speed movement by the passive wheel of the tip of each leg of the four-legged robot named "Road Strider”, which can perform the leg-wheel hybrid locomotion. It moves on a flat plane by wheels and on the rough terrain with legs. “Road Strider” has unique joint mechanism which uses singular point to reduce the energy consumption when the robot stands. High energy-effectiveness is suitable for the various application, especially the robots acts in the extreme situation like a rescue mission. To measure precisely the surrounding environment, it is important to move the robot at constant speed. To make the constant speed movement, constant velocity motion in wheel motion is considered and implemented to the robot.

馬型4脚ロボット後脚の軽量化

馬型4脚ロボット後脚の軽量化

Foot Structure with Divided Flat Soles and Springs for Legged Robots and Experimental Verification

[abstFig src='/00280006/03.jpg' width='300' text='Robotic foot adaptable to rough terrain' ] Practical ambulation must be realized by walking robots to enable social and industrial support by walking robots in human living environments. A four-legged robot that walks through rough terrain effectively does not erase the fact that most legged robots – particularly biped robots – have difficulty negotiating rough terrain. We focus below on a foot structure and landing control for enabling any type of legged robot to walk through rough terrain. When a walking robot lands on the ground, it is difficult to detect the detailed geometry and dynamic properties of the ground surface. The new foot structure we propose adapts to ground surfaces that have different geometries and hardness. The foot has four-part flat soles. The landing controller we apply to a robot with our proposed foot structure increases the stability of contact with the ground. We verify the effectiveness of our proposed foot structure in experiments.

Improved forward kinematic analysis of a reptile-like four-legged walking robot using a novel dimensionality-reduction method

A new forward kinematic analysis is proposed to describe the motion of a reptile-like four-legged walking robot using a new dimensionality-reduction method. The three standing legs (assuming one leg is swinging) contain nine driven joints. Only six of these joints, however, are independently driven joints. The remaining joints are redundant driven joints. Finding the redundant driven joint angles has been a key problem in improved forward kinematic analysis of a reptile-like forward kinematic analysis. Solving the associated high-order equation, which is derived using the analytic method, is problematic and slow. In this paper, we use a new dimensionality reduction method to solve this problem. First, we deduced the formulas for the redundant driven joint angles. Then, one of the formulas is transformed to take into account the constraint condition. We then use iteration to find solutions for the remaining equations that satisfy the constraint condition. With the help of MATLAB, a solving system for the forward kinematic analysis of this robot is introduced. Our results show two improvements over the conventional method: shorter computation time and higher precision.