Dynamic Modeling and Locomotion Control for Quadruped Robots Based on Center of Inertia on SE(3)

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Xilun Ding ◽  
Hao Chen
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Dynamic Control ◽  
Quadruped Robot ◽  
The Body ◽  
State Variables ◽  
Complex Environments ◽  
Simulation Experiments ◽  
Quadruped Robots ◽  
Virtual Body

Quadruped robots have good mobility and agility in complex environments, but dynamic control of locomotion for quadruped robots has long been a big challenge for researchers. In this paper, we build the center of inertia (COI) dynamic model of a general quadruped robot and give the exponential coordinates of COI on the special Euclidean space SE(3). The COI model takes the whole quadruped robot as one body, so that the only concern is the movement of the COI rather than the body or legs when the robot walks. As a result, the COI model has fewer dimensions of state variables than the full dynamic model, which helps to reduce the computational load. A control method for quadruped robots is presented based on the dynamic model which is constituted of force loop and position loop. This method controls the movement of the COI directly, so it facilitates to guarantee the robot's stability. The virtual body of the quadruped robot is defined to describe the configuration of the quadruped robot. The proportional-derivative (PD) control method on SE(3) is applied to control the movement of the virtual body, which makes the movement more in line with the group theoretic viewpoint. Finally, some simulation experiments have been conducted to verify the validity of our method.

Full Leg Control of a Quadruped Robot Using Linear Visual Servoing with a Stereo Omnidirectional Camera

2011 ◽  
Vol 5 (2) ◽  
pp. 241-246
Author(s):  
Yukinari Inoue ◽  
◽  
Noriaki Maru ◽  
Keyword(s):  
Visual Servoing ◽  
Visual Space ◽  
Quadruped Robot ◽  
The Body ◽  
Field Of View ◽  
Transformation Equation ◽  
Stereo Camera ◽  
Omnidirectional Camera ◽  
Quadruped Robots ◽  
Omnidirectional Image

The authors have previously proposed foot tip control for quadruped robots using linear visual servoing (LVS) with a normal stereo camera. However, a normal stereo camera has a narrow field of view and is incapable of seeing all four legs simultaneously. Consequently, it has been a problem that the control of all the legs have required that the rotatation of the camera be controlled. This article proposes a method by which a stereo omnidirectional camera is provided at a position low on the body to control all four legs through LVS. In this article, we at first present a transformation equation from an omnidirectional image to a binocular visual space, and we develop a servo equation of LVS in which an omnidirectional image is used. Then, through simulation, we confirm trajectories with the LVS applied to foot tip control. We also conduct an experiment using TITAN-VIII to demonstrate the efficacy of the proposed method.

Torque control of new energy four wheel hub motor based on distribution algorithm

2021 ◽  
pp. 29-41
Author(s):  
Shuai Leng ◽  
◽  
Liqiang Jin ◽  
Keyword(s):  
Control Method ◽  
The Body ◽  
Torque Control ◽  
State Variables ◽  
Motor Speed ◽  
Control Effect ◽  
New Energy ◽  
Optimal Efficiency ◽  
Stator Flux ◽  
The Stability

Due to the nonlinear, strong coupling and uncertain parameters of the new energy four-wheel hub motor, it is more difficult to control the torque of the motor. In order to solve this problem, a torque control method of the new energy four-wheel hub motor based on the distribution algorithm is proposed. The dynamic model of the new energy four-wheel hub motor is established, and the unmeasurable flux, electric power and other state variables in the motor model are derived according to the degree of freedom of the body. The whole four-wheel hub motor is taken as the research object, and the optimal efficiency of the drive system is taken as the goal, and the distribution algorithm is used to control the electromagnetic torque of the motor. The simulation results show that after the torque control of new energy four wheel hub motor, the driving range of the vehicle is longer, the amplitude of stator flux changes little, the stator current changes and the stability of motor speed are good, and the torque control effect is better.

Mechanism design of a biomimetic quadruped robot

2017 ◽  
Vol 44 (4) ◽  
pp. 512-520 ◽  
Author(s):  
Zhao Tang ◽  
Peng Qi ◽  
Jian Dai
Keyword(s):  
Stick Insect ◽  
Quadruped Robot ◽  
The Body ◽  
Body Structure ◽  
Content Type ◽  
Stability Margins ◽  
Quadruped Robots ◽  
Novel Design ◽  
Practical Implications ◽  
Current Stage

Purpose This paper aims to introduce a novel design of the biomimetic quadruped robot, including its body structure, three structural modes and respective workspace. Design/methodology/approach By taking a metamorphic 8-bar linkage as the body of a quadruped robot, the authors propose a reconfigurable walking robot that can imitate three kinds of animals: mammals (e.g. dog), arthropods (e.g. stick insect) and reptiles (e.g. lizard). Furthermore, to analyze the three structural modes of this quadruped robot, the workspace is calculated and studied. Findings Based on experimental data analyses, it is revealed that the metamorphic quadruped robot can walk in all its three structural modes and adapt to different terrains. Research limitations/implications Because the body of the quadruped robot is deformable and reconfigurable, the location of payload is not considered in the current stage. Practical implications The relative positions and postures of legs of the metamorphic robot can be rearranged during its body reconfiguration in such a way to combine all the features of locomotion of the three kinds of animals into one robot. So, the metamorphic quadruped robot is capable of maintaining wider stability margins than conventional rigid-body quadruped robots and conducting operations in different environments, particularly the extreme and restricted occasions due to the changeable and adaptable trunk. Originality/value The main contribution is the development of a reconfigurable biomimetic quadruped robot, which uses the metamorphic 8-bar linkage. This robot can easily reshape to three different structural modes and mimic the walking patterns of all mammals, arthropods and reptiles.

A new effective nonlinear strategy for lateral stability increment of an articulated vehicle rigid cargo

2021 ◽  
pp. 095440702110090
Author(s):  
Mohammad Amin Saeedi
Keyword(s):  
Dynamic Model ◽  
Feedback Linearization ◽  
Control Method ◽  
Sliding Mode ◽  
Center Of Mass ◽  
Front Axle ◽  
System Stability ◽  
State Variables ◽  
Lateral Velocity ◽  
Articulated Vehicle

In this paper, the effects of the most important parameters on directional dynamics of a tractor-semitrailer vehicle are examined. Initially, a three DOF dynamic model of a tractor-semitrailer vehicle is proposed. Then, the developed model is validated by means of TruckSim software during a standard maneuver. In order to analyze the system stability, the Lyapunov method has been used and the stability conditions have been extracted based on Routh criterion. The most important parameters are selected based on the articulation angle gain. Among the studied parameters, the semitrailer mass, the distance of the tractor unit center of mass and its front axle, and the tires cornering stiffness exhibited more effective behavior on the vehicle’s stability. The simulation results show that as the tractor center of mass moves toward its rear axle, the probability of the jackknifing increases. Moreover, an increment in the semitrailer mass leads to a turn of the semitrailer with respect to the tractor. Also, the understeer specification of the vehicle strengthens due to the tire cornering stiffness increment. Moreover, in order to increase the maneuverability of the articulated vehicle a new active steering controller is proposed using two different control methods. The controller is developed using the simplified dynamic model and the basis of feedback linearization method using dynamic sliding mode control method. In this system, the yaw rate and the lateral velocity of the tractor unit as well as articulation angle are studied as state variables which are targeted to track their desired references. Then, the vehicle dynamic performance is investigated during standard maneuvers. A more investigation shows that the track of the desired values of the vehicle state variables leads to eliminate off-tracking path.

Analysis of the Energy Loss on Quadruped Robot Having a Flexible Trunk Joint

2017 ◽  
Vol 29 (3) ◽  
pp. 536-545
Author(s):  
Masahiro Ikeda ◽  
◽  
Ikuo Mizuuchi
Keyword(s):  
Energy Loss ◽  
Energy Flow ◽  
Control Method ◽  
Quadruped Robot ◽  
Rough Terrain ◽  
Legged Robot ◽  
Walking Robot ◽  
Passive Joint ◽  
Quadruped Robots ◽  
The Relationship

[abstFig src='/00290003/09.jpg' width='300' text='Energy flow in legged robot' ] As a method of robot movement, legs have the advantage of traversability on rough terrain. However, the motion of a legged robot is accompanied by energy loss. The main causes for this loss could be negative work and contact between the legs and ground. On the other hand, animals with legs are considered to reduce energy loss by using the elasticity of their body. In this study, we analyze the influence of walking, using an elastic passive joint mounted on the trunk of a quadruped robot, on the energy loss. Additionally, we study the energy flow between legs and elastic components. In this study, we clarify a control method for quadruped robots in order to reduce the energy loss of walking. The results of simulating a quadruped walking robot, which has passive joints with elastic components on the trunk, are analyzed and the relationship between each kind of energy loss and the trunk joint’s elasticity is clarified.

scholarly journals Bio-Inspired Take-Off Maneuver and Control in Vertical Jumping for Quadruped Robot with Manipulator

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1189
Author(s):  
Ru Kang ◽  
Fei Meng ◽  
Lei Wang ◽  
Xuechao Chen ◽  
Zhangguo Yu ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Quadruped Robot ◽  
The Body ◽  
Lower Limbs ◽  
Whole Body ◽  
Hierarchical Optimization ◽  
Arm Swing ◽  
Joint Torques ◽  
Exploration Environment

The jumping motion of legged robots is an effective way to overcome obstacles in the rugged microgravity planetary exploration environment. At the same time, a quadruped robot with a manipulator can achieve operational tasks during movement, which is more practical. However, the additional manipulator will restrict the jumping ability of the quadruped robot due to the increase in the weight of the system, and more active degrees of freedom will increase the control complexity. To improve the jumping height of a quadruped robot with a manipulator, a bio-inspired take-off maneuver based on the coordination of upper and lower limbs is proposed in this paper. The kinetic energy and potential energy of the system are increased by driving the manipulator-end (ME) to swing upward, and the torso driven by the legs will delay reaching the required peak speed due to the additional load caused by the accelerated ME. When the acceleration of ME is less than zero, it will pull the body upward, which reduces the peak power of the leg joints. Therefore, the jumping ability of the system is improved. To realize continuous and stable jumping, a control framework based on whole-body control was established, in which the quadruped robot with a manipulator was a simplified floating seven-link model, and the hierarchical optimization was used to solve the target joint torques. This method greatly simplifies the dynamic model and is convenient for calculation. Finally, the jumping simulations in different gravity environments and a 15° slope were performed. The jump heights have all been improved after adding the arm swing, which verified the superiority of the bio-inspired take-off maneuver proposed in this paper. Furthermore, the stability of the jumping control method was testified by the continuous and stable jumping.

scholarly journals Gait Transition from Pacing by a Quadrupedal Simulated Model and Robot with Phase Modulation by Vestibular Feedback

Robotics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Takahiro Fukui ◽  
Souichiro Matsukawa ◽  
Yasushi Habu ◽  
Yasuhiro Fukuoka
Keyword(s):  
Phase Modulation ◽  
Control Method ◽  
Pattern Generator ◽  
The Body ◽  
Body Tilt ◽  
Effective Control ◽  
Pd Controller ◽  
Gait Transition ◽  
Quadruped Robots ◽  
High Speeds

We propose a method to achieve autonomous gait transition according to speed for a quadruped robot pacing at medium speeds. We verified its effectiveness through experiments with the simulation model and the robot we developed. In our proposed method, a central pattern generator (CPG) is applied to each leg. Each leg is controlled by a PD controller based on output from the CPG. The four CPGs are coupled, and a hard-wired CPG network generates a pace pattern by default. In addition, we feed the body tilt back to the CPGs in order to adapt to the body oscillation that changes according to the speed. As a result, our model and robot achieve stable changes in speed while autonomously generating a walk at low speeds and a rotary gallop at high speeds, despite the fact that the walk and rotary gallop are not preprogramed. The body tilt angle feedback is the only factor involved in the autonomous generation of gaits, so it can be easily used for various quadruped robots. Therefore, it is expected that the proposed method will be an effective control method for quadruped robots.

scholarly journals A Neural Network Based Dynamic Control Method for Soft Pneumatic Actuator with Symmetrical Chambers

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 112
Author(s):  
Yiqing Li ◽  
Yan Cao ◽  
Feng Jia
Keyword(s):  
Neural Network ◽  
Dynamic Model ◽  
Trajectory Tracking ◽  
Tracking Control ◽  
Control Method ◽  
Dynamic Control ◽  
The State ◽  
Pneumatic Actuator ◽  
Trajectory Tracking Control ◽  
Modeling And Control

Dynamic modeling and control of the soft pneumatic actuators are challenging research. In this paper, a neural network based dynamic control method used for a soft pneumatic actuator with symmetrical chambers is proposed. The neural network is introduced to create the dynamic model for predicting the state of the actuator. In this dynamic model, the effect of the uninflated rubber block on bending deformation is considered. Both pressures of the actuator are used for predicting the state of the actuator during the bending motion. The controller is designed based on this dynamic model for trajectory tracking control. Three types of trajectory tracking control experiments are performed to validate the proposed method. The results show that the proposed control method can control the motion of the actuator and track the trajectory effectively.

scholarly journals Design and Control of a Novel Single Leg Structure of Electrically Driven Quadruped Robot

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Mingfang Chen ◽  
Hao Chen ◽  
Xuejun Wang ◽  
JiangXuan Yu ◽  
YongXia Zhang
Keyword(s):  
Control Method ◽  
Good Control ◽  
Quadruped Robot ◽  
Structure Design ◽  
The Body ◽  
Interpolation Algorithm ◽  
Control Effect ◽  
Simulation And Experiment ◽  
Control Principle ◽  
And Control

In order to solve the defects of the large inertia and control difficulty of the electrically driven quadruped legs of robots, a novel leg structure and a control method are proposed in this paper. In terms of structure, the motor of the knee is arranged in the body of the robot to reduce the weight of the legs. In addition, this paper improves the PVT difference control algorithm embedded in the PMAC controller. Using the nonlinear control principle of the U-model, the optimized segmented Hermite difference method is used to implement the planning of the foot trajectory of the quadruped robot. Simulation and experiment show that the leg structure design is reasonable and the improved interpolation algorithm has good control effect.

Dynamic Parameters and Friction Model Identification of an Industrial Hybrid Robot

2019 ◽  
Author(s):  
Binbin Zhang ◽  
Liping Wang ◽  
Jun Wu
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Driving Forces ◽  
Dynamic Control ◽  
Model Identification ◽  
Friction Model ◽  
Dynamic Parameters ◽  
Typical Trajectory ◽  
Lagrangian Dynamic ◽  
Moving Speed

Abstract To obtain higher performance for an industrial hybrid robot, the dynamic control method is utilized to control the robot. For dynamic control, the control performance is directly affected by the accuracy of the dynamic model. This paper investigated a method to establish and identify an accurate dynamic model. First, based on the Lagrangian dynamic equation and the Stribeck friction model, the unidentified dynamic model of the five-DOF hybrid robot is established. Second, identification experiments are carried out. Each of the driving joints performs frequent reciprocating motions individually. In the meantime, the moving speed is gradually increased to obtain driving torques of the respective joint at different moving speeds. Then the dynamic parameters with lower coupling are identified by using the standard deviation index and the least squares methods until all parameters are gradually determined. Finally, the hybrid robot moves a typical trajectory, while the currents of each joint are collected to obtain the driving forces. The actual driving forces, the identified dynamic model, and the unidentified dynamic model are compared. The results show that the identified method could significantly improve the accuracy of the dynamic model. The method proposed in this paper is general and can be applied to the other robots without adding any sensors.

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