scholarly journals Gait Tracking Control of Quadruped Robot Using Differential Evolution Based Structure Specified Mixed SensitivityH∞Robust Control

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Petrus Sutyasadi ◽  
Manukid Parnichkun
Keyword(s):  
Tracking Control ◽  
Control Algorithm ◽  
Joint Angle ◽  
Gait Pattern ◽  
Quadruped Robot ◽  
Robust Controller ◽  
Quadruped Robots ◽  
Parameter Variations ◽  
Real Hardware ◽  
Dynamic Gait

This paper proposed a control algorithm that guarantees gait tracking performance for quadruped robots. During dynamic gait motion, such as trotting, the quadruped robot is unstable. In addition to uncertainties of parameters and unmodeled dynamics, the quadruped robot always faces some disturbances. The uncertainties and disturbances contribute significant perturbation to the dynamic gait motion control of the quadruped robot. Failing to track the gait pattern properly propagates instability to the whole system and can cause the robot to fall. To overcome the uncertainties and disturbances, structured specified mixed sensitivityH∞robust controller was proposed to control the quadruped robot legs’ joint angle positions. Before application to the real hardware, the proposed controller was tested on the quadruped robot’s leg planar dynamic model using MATLAB. The proposed controller can control the robot’s legs efficiently even under uncertainties from a set of model parameter variations. The robot was also able to maintain its stability even when it was tested under several terrain disturbances.

scholarly journals Multi-Phase Joint-Angle Trajectory Generation Inspired by Dog Motion for Control of Quadruped Robot

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6366
Author(s):  
Jungsu Choi
Keyword(s):  
Basis Function ◽  
Joint Angle ◽  
Trajectory Generation ◽  
Humanoid Robots ◽  
Quadruped Robot ◽  
Continuous Transition ◽  
Quadruped Robots ◽  
Gait Phase ◽  
Locomotion Speed ◽  
Multi Phase

Quadruped robots are receiving great attention as a new means of transportation for various purposes, such as military, welfare, and rehabilitation systems. The use of four legs enables a robustly stable gait; compared to the humanoid robots, the quadruped robots are particularly advantageous in improving the locomotion speed, the maximum payload, and the robustness toward disturbances. However, the more demanding conditions robots are exposed to, the more challenging the trajectory generation of robotic legs becomes. Although various trajectory generation methods (e.x., central pattern generator, finite states machine) have been developed for this purpose, these methods have limited degrees of freedom with respect to the gait transition. The conventional methods do not consider the transition of the gait phase (i.e., walk, amble, trot, canter, and gallop) or use a pre-determined fixed gait phase. Additionally, some research teams have developed locomotion algorithms that take into account the transition of the gait phase. Still, the transition of the gait phase is limited (mostly from walking to trot), and the transition according to gait speed is not considered. In this paper, a multi-phase joint-angle trajectory generation algorithm is proposed for the quadruped robot. The joint-angles of an animal are expressed as a cyclic basis function, and an input to the basis function is manipulated to realize the joint-angle trajectories in multiple gait phases as desired. To control the desired input of a cyclic basis function, a synchronization function is formulated, by which the motions of legs are designed to have proper ground contact sequences with each other. In the gait of animals, each gait phase is optimal for a certain speed, and thus transition of the gait phases is necessary for effective increase or decrease in the locomotion speed. The classification of the gait phases, however, is discrete, and thus the resultant joint-angle trajectories may be discontinuous due to the transition. For the smooth and continuous transition of gait phases, fuzzy logic is utilized in the proposed algorithm. The proposed methods are verified by simulation studies.

scholarly journals Stability Criterion for Dynamic Gaits of Quadruped Robot

2018 ◽  
Vol 8 (12) ◽  
pp. 2381 ◽  
Author(s):  
Yan Jia ◽  
Xiao Luo ◽  
Baoling Han ◽  
Guanhao Liang ◽  
Jiaheng Zhao ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Stability Criterion ◽  
Quadruped Robot ◽  
Stability Criteria ◽  
Irregular Terrain ◽  
Quadruped Robots ◽  
Simulation Results ◽  
Zero Moment ◽  
The Stability ◽  
Dynamic Gait

Dynamic-stability criteria are crucial for robot’s motion planning and balance recovery. Nevertheless, few studies focus on the motion stability of quadruped robots with dynamic gait, none of which have accurately evaluated the robots’ stability. To fill the gaps in this field, this paper presents a new stability criterion for the motion of quadruped robots with dynamic gaits running over irregular terrain. The traditional zero-moment point (ZMP) is improved to analyze the motion on irregular terrain precisely for dynamic gaits. A dynamic-stability criterion and measurement are proposed to determine the stability state of the robot and to evaluate its stability. The simulation results show the limitations of the existing stability criteria for dynamic gaits and indicate that the criterion proposed in this paper can accurately and efficiently evaluate the stability of a quadruped robot using such gaits.

scholarly journals Optimal Covid-19 Based PD/PID Cascaded Tracking Control for Robot Arm driven by BLDC Motor

2021 ◽  
Vol 20 ◽  
pp. 217-227
Author(s):  
Mohamed A. Shamseldin
Keyword(s):  
Tracking Control ◽  
Pid Controller ◽  
Control Algorithm ◽  
Harmony Search ◽  
Optimization Techniques ◽  
Robot Arm ◽  
Continuous Change ◽  
Parameter Variations ◽  
Optimal Values ◽  
Proper Values

This paper presents an efficient covid-19 optimization algorithm to find the optimal values of the PD/PID cascaded controller. The purpose of the control algorithm is to force the link shaft to follow the desired reference position with good accuracy all time. This objective should be achieved for different position/time tracks regardless of load disturbance and parameter variations. This work, simulating how the covid-19 spreads and infects to optimize the parameters of the PD/ PID control. The initial values of PD/PID controller parameters consider the zero patient, which infects new patients (other values of PD/PID controller parameters). The optimization model simulates as accurately as possible the covid-19 activity. The covid-19 has two major advantages compared to other similar strategies. First, the covid-19 parameters are already adjusted according to disease statistics to prevent designers from initializing them with arbitrary values. Second, the approach has the ability to finish after several iterations where the infected population initially grows at an exponential rate. However, after some iterations. The proposed covid-19 was investigated with well-known optimization techniques such as the genetic algorithm (GA) and Harmony Search (HS) optimization. A multi-objective function is used to allow the designer to select the desired rise time, the desired settling time, the desired overshoot, and the desired steady-state error. Several tests have been performed to investigate the obtained proper values of PD/PID controller parameters. In the first test, a step position reference had been applied. In the second test, the continuous change in position reference had been subjected to the robot arm. The results provide that the covid-19 based PD/PID controller has the best performance among other techniques. In addition, the covid-19 based PID controller can track accurately the position command compared to other techniques.

scholarly journals Single-Leg Structural Design and Foot Trajectory Planning for a Novel Bioinspired Quadruped Robot

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Mingfang Chen ◽  
Qi Li ◽  
Sen Wang ◽  
Kaixiang Zhang ◽  
Hao Chen ◽  
...  
Keyword(s):  
Structural Design ◽  
Control Algorithm ◽  
Quadruped Robot ◽  
Rational Structure ◽  
Flight Phase ◽  
Experimental Platform ◽  
Quadruped Robots ◽  
The Stability ◽  
The Impact ◽  
Foot Trajectory

To meet the stability requirements for moving quadruped robots, it is important to design a rational structure for a single leg and plan the trajectory of the foot. First, a novel electrically driven leg mechanism for a quadruped robot is designed in this paper to reduce the inertia of the leg swing. Second, a modified foot trajectory based on a compound cycloid is proposed, which has swing-back and retraction motion and continuous velocity in the x-axis direction. Third, a Simulink platform is built to verify the correctness of the proposed foot trajectory. The simulation result shows that when the flight phase and the stand phase switch, the impact of torque is smaller than the foot trajectory before modification. Finally, an experimental platform is constructed, and a control algorithm is written into the controller to realize the foot proposed trajectory. The results of the experiment prove the feasibility of the leg mechanism and the rationality of the proposed foot trajectory.

Fault-Tolerant Formation Tracking Control for Heterogeneous Multiagent Systems with Directed Topology

2021 ◽  
Vol 01 (01) ◽  
pp. 2150001
Author(s):  
Jianye Gong ◽  
Yajie Ma ◽  
Bin Jiang ◽  
Zehui Mao
Keyword(s):  
Tracking Control ◽  
Formation Control ◽  
Control Algorithm ◽  
Fault Tolerant ◽  
Control Technique ◽  
Fault Estimation ◽  
Consensus Control ◽  
Formation Tracking ◽  
Control Scheme ◽  
Aerial Vehicle

In this paper, the adaptive fault-tolerant formation tracking control problem for a set of heterogeneous unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) systems with actuator loss of effectiveness faults is investigated. The cooperative fault-tolerant formation control strategy for UAV and UGV collaborative systems is classified into the altitude consensus control scheme for follower UAVs and the position cooperative formation control scheme for all followers. The altitude consensus control algorithm is designed by utilizing backstepping control technique to drive all UAVs to a desired predefined height. Then, based on synchronization formation error information, the position cooperative formation control algorithm is proposed for all followers to reach the expected position and perform the desired formation configuration. The adaptive fault estimation term is adopted in the designed fault-tolerant formation control algorithm to compensate for the actuator loss of effectiveness fault. Finally, a simulation example is proposed to reveal the validity of the designed cooperative formation tracking control scheme.

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