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 Whole-body kinematic and dynamic modeling for quadruped robot under different gaits and mechanism topologies

2021 ◽  
Vol 7 ◽  
pp. e821
Author(s):  
Wei Yan ◽  
Yang Pan ◽  
Junjie Che ◽  
Jiexian Yu ◽  
Zhuchen Han
Keyword(s):  
Dynamic Modeling ◽  
Screw Theory ◽  
Control Strategies ◽  
Quadruped Robot ◽  
The Body ◽  
Joint Torque ◽  
Sensor Data ◽  
Whole Body ◽  
Measurement Unit ◽  
Body Kinematic

Dynamic locomotion plays a crucial role for legged robots to fulfill tasks in unstructured environments. This paper proposes whole-body kinematic and dynamic modeling method s based on screw theory for a quadruped robot using different gaits and mechanism topologies. Unlike simplified models such as centroid or inverse pendulum models, the methods proposed here can handle 10-dimensional mass and inertia for each part. The only simplification is that foot contact models are treated as spherical joints. Models of three different mechanism topologies are formulated: (1) Standing phase: a system consisting of one end-effector, the body, and four limbs, the legs; (2) Walking phase: a system consisting of one or two lifting legs (depending on the chosen gait), two or three supporting legs; (3) Floating phase: a system in which all legs detach from the ground. Control strategies based on our models are also introduced, which includes walk and trot gait plans. In our control system, two additional types of information are provided: (1) contacting forces are given by force sensors installed under feet; (2) body poses are determined by an inertial measurement unit (IMU). Combined with the sensor data and calibrated mass, inertia, and friction, the joint torque can be estimated accurately in simulation and experiment. Our prototype, the “XiLing” robot, is built to verify the methods proposed in this paper, and the results show that the models can be solved quickly and leads to steady locomotions.

Numerical Study on Scale Effect of KCS

2019 ◽  
Author(s):  
Yujie Zhou ◽  
Liwei Liu ◽  
Xiao Cai ◽  
Dakui Feng ◽  
Bin Guo
Keyword(s):  
Scale Effect ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Numerical Study ◽  
The Body ◽  
The Self ◽  
Body Motion ◽  
Propulsion Performance ◽  
Calm Water ◽  
Unsteady Rans

Abstract The key objective of this paper is to perform a fully nonlinear unsteady RANS simulation to predict the self-propulsion performance of KCS at two different scales. This simulations are performed at design speeds in calm water, using inhouse computational fluid dynamics (CFD) to solve RANS equation coupled with two degrees of freedom (2DOF) solid body motion equations including heave and pitch. The SST k-ω turbulence equation is discretized by finite difference method. The velocity pressure coupling is solved by PISO algorithm. Computations have used structured grid with overset technology. The single-phase level-set method is used to capture the free surface. The simulations of self-propulsion are based on the body-force method. The PID control method is applied to match the speed of KCS by changing the propeller rotation speed automatically. In this paper, the self-propulsion factors of KCS at two scales are predicted and the results from inhouse CFD code are compared with the EFD date, and then the reasons for the scale effect have been discussed.

Dynamic Performance Experiment and Fuzzy PID Control Method Study on MRF Engine Mount

2012 ◽  
Vol 542-543 ◽  
pp. 675-678
Author(s):  
Suo Jun Hou ◽  
Wen Ku Shi ◽  
Mao Yang ◽  
Hai Sheng Li
Keyword(s):  
Pid Control ◽  
Degrees Of Freedom ◽  
Engine Speed ◽  
Control Method ◽  
Dynamic Performance ◽  
Low Frequency ◽  
The Body ◽  
Fuzzy Pid ◽  
Fuzzy Pid Control ◽  
Engine Mount

A MRF fluid engine mount with controlled annular access, inertia track and decoupler is designed. Through the experiment it can be seen that the low frequency performance of the mount is greatly improved. Then the dynamic low frequency performance of the mount using the fuzzy PID control method of two degrees-of-freedom system in different engine speed is simulated and the results show that the fuzzy PID control method is effective to reduce the body acceleration.

Power Assist Control Calculated by a Human Model and Joint Angles for Walking Motion Using Pneumatic Actuators

2013 ◽  
Vol 25 (6) ◽  
pp. 915-922 ◽  
Author(s):  
Motonobu Sato ◽  
◽  
Eiichi Yagi ◽  
Kazuo Sano ◽  
Keyword(s):  
Control Method ◽  
The Body ◽  
Human Model ◽  
Joint Angles ◽  
Pneumatic Actuators ◽  
Joint Torques ◽  
Rigid Link ◽  
Walking Motion ◽  
Link Model

This paper describes a method for power assist control that calculates the joint torques necessary to support an assist suit wearer’s walking. We approximate the body using a multijoint rigid link model. Joint support torques are calculated based on this model using the hip, knee and ankle angles of the wearer. Results of experiments show the effectiveness of proposed control method.

Robust Sliding Mode Control of a Full Vehicle Without Suspension Gap Loss

2005 ◽  
Vol 11 (11) ◽  
pp. 1357-1374 ◽  
Author(s):  
N. Yagiz ◽  
L. E. Sakman
Keyword(s):  
Sliding Mode Control ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Control Method ◽  
Sliding Mode ◽  
The Body ◽  
Vehicle Body ◽  
New Approach ◽  
Full Vehicle ◽  
Mode Control

A seven-degrees-of-freedom full vehicle model is used to design a robust controller and to investigate the performance of active suspensions without losing the suspension working space. Zero reference for vehicle body displacement finishes suspension working distance. Thus, a new approach is suggested in this paper. Force actuators are placed parallel to the suspensions and non-chattering sliding mode control is applied. Since any change in vehicle parameters because of different load or road conditions adversely affects the performance of the ordinary control methods, a robust control method is preferred. To obtain the desired improvement in ride comfort, we aim to decrease the magnitudes of the body vibrations and their accelerations. We present body bounce, pitch and roll motions of the vehicle with the conventional approach and the proposed approach without suspension gap loss, both in the time domain in the case of traveling over a step road profile and in the frequency domain. The results of both approaches are compared. The solution to the suspension gap loss problem has also been presented on periodic road surfaces. At the end of the paper, we discuss the improvement in the performance of the new controller with its robust behavior and the advantage of the new approach.

scholarly journals Whole-Body Pose Estimation in Physical Rider–Bicycle Interactions With a Monocular Camera and Wearable Gyroscopes

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Xiang Lu ◽  
Kaiyan Yu ◽  
Yizhai Zhang ◽  
Jingang Yi ◽  
Jingtai Liu ◽  
...  
Keyword(s):  
Pose Estimation ◽  
The Body ◽  
Lower Limbs ◽  
Human Anatomy ◽  
Whole Body ◽  
Monocular Camera ◽  
Single Feature ◽  
Estimation Scheme ◽  
Inertial Measurements ◽  
Body Pose Estimation

Pose estimation of human–machine interactions such as bicycling plays an important role to understand and study human motor skills. In this paper, we report the development of a human whole-body pose estimation scheme with application to rider–bicycle interactions. The pose estimation scheme is built on the fusion of measurements of a monocular camera on the bicycle and a set of small wearable gyroscopes attached to the rider's upper- and lower-limbs and the trunk. A single feature point is collocated with each wearable gyroscope and also on the body segment link where the gyroscope is not attached. An extended Kalman filter (EKF) is designed to fuse the visual-inertial measurements to obtain the drift-free whole-body poses. The pose estimation design also incorporates a set of constraints from human anatomy and the physical rider–bicycle interactions. The performance of the estimation design is validated through ten subject riding experiments. The results illustrate that the maximum errors for all joint angle estimations by the proposed scheme are within 3 degs. The pose estimation scheme can be further extended and used in other types of physical human–machine interactions.

scholarly journals Biomechanical factor affecting Baseball Pitching Velocity

2019 ◽  
Author(s):  
Yasushi Ota ◽  
Ryoga Kuriyama
Keyword(s):  
High Speed ◽  
Time Series Data ◽  
Three Dimensional ◽  
The Body ◽  
Lower Limbs ◽  
Whole Body ◽  
Series Data ◽  
Physical Factors ◽  
Body Parts ◽  
Joint Force

In baseball, pitchers have a central role and high-speed pitching is desirable. So far, several studies of the physical factors related to pitching form with the aim of improving the speed of pitched balls have been conducted. In this study, we used a motion capture to acquire three-dimensional (3D) time series data related to the speed of pitched balls and performed a kinetics analysis by using these acquired data. The acquired data were divided into five pitching phases: wind up, early cocking, late cocking, acceleration, and follow through. Our analysis identified the body parts that contribute to increasing the speed of pitched balls, i.e., the speed of rotation of individual joints and the timing/phase when power can be applied. Especially, by examining joint angular velocity and joint force, we showed that the speed of pitched balls is determined by the action of the upper limbs as well as the coordinated action of the whole body, particularly the lower limbs and the trunk.

scholarly journals Clinical Retrospective Analysis of Critically Severe Necrotizing Fasciitis

2020 ◽  
Author(s):  
XIAOPING YU ◽  
ZHENG GUO ◽  
JUN LIU ◽  
JIAN WU ◽  
JUNLI ZHOU
Keyword(s):  
Necrotizing Fasciitis ◽  
Pressure Ulcer ◽  
The Body ◽  
Lower Limbs ◽  
Whole Body ◽  
Comprehensive Treatment ◽  
Low Grade ◽  
Minor Trauma ◽  
Effective Manner ◽  
Local Trauma

Abstract BackgroundToexploretheclinicaldiagnosisandtreatmentoffatalnecrotizingfasciitis.MethodsRetrospective analysis of simple data from January 1, 2014 to November 1, 2019, on the clinical data of the Department of Burns, Gansu Provincial People's Hospital, and the diagnosis and treatment methods were discussed.ResultsThe usual causes of necrosis and fasciitis are as follows. 1. Small trauma such as mosquito bites, pressure sores, and local trauma; 2. Patients suffering from minor trauma did not receive regular treatment in time, and only went to the hospital when local redness, pain, and dysfunction occurred, and were misdiagnosed as cellulitis;3. When a paraplegic patient has a Sacrococcygeal pressure ulcer and has whole-body fever or low-grade fever, and there is inflammation around the pressure ulcer, and redness and swelling spread to one lower limb or both lower limbs, necrotizing fasciitis should be highly suspected; 4. Patients’ wounds cannot be debrided in a timely and effective manner. Generally, inexperienced doctors have incomplete incision and drainage, which causes necrosis to continue to spread along the fascia to the distal limbs.Conclusion1. The diagnosis of necrotizing fasciitis mainly depends on clinical manifestations, and early diagnosis is the key; 2. When the patient has local trauma with local inflammation, and fever or hypothermia throughout the body, necrotizing fasciitis should be highly suspected, and the differential diagnosis should be made with cellulitis. When it is difficult to distinguish, a diagnostic surgical incision can be performed; 3. The operation should be thorough, fully cut and drained to avoid necrosis spreading to the distal limbs along the fascial space; 4. Necrotizing fasciitis should be systemic comprehensive treatment, rational use of antibiotics, correction of water and electrolyte disorders, early active and thorough debridement, and effective sealing of the wound.

Optimal Combination of Minimum Degrees of Freedom to be Actuated in the Lower Limbs to Facilitate Arm-Free Paraplegic Standing

2007 ◽  
Vol 129 (6) ◽  
pp. 838-847 ◽  
Author(s):  
Joon-young Kim ◽  
James K. Mills ◽  
Albert H. Vette ◽  
Milos R. Popovic
Keyword(s):  
Lower Limb ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Optimal Combination ◽  
Lower Limbs ◽  
Free Standing ◽  
Joint Torques ◽  
Flexion Extension ◽  
Hip Abduction ◽  
The Individual

Arm-free paraplegic standing via functional electrical stimulation (FES) has drawn much attention in the biomechanical field as it might allow a paraplegic to stand and simultaneously use both arms to perform daily activities. However, current FES systems for standing require that the individual actively regulates balance using one or both arms, thus limiting the practical use of these systems. The purpose of the present study was to show that actuating only six out of 12 degrees of freedom (12-DOFs) in the lower limbs to allow paraplegics to stand freely is theoretically feasible with respect to multibody stability and physiological torque limitations of the lower limb DOF. Specifically, the goal was to determine the optimal combination of the minimum DOF that can be realistically actuated using FES while ensuring stability and able-bodied kinematics during perturbed arm-free standing. The human body was represented by a three-dimensional dynamics model with 12-DOFs in the lower limbs. Nakamura’s method (Nakamura, Y., and Ghodoussi, U., 1989, “Dynamics Computation of Closed-Link Robot Mechanisms With Nonredundant and Redundant Actuators,” IEEE Trans. Rob. Autom., 5(3), pp. 294–302) was applied to estimate the joint torques of the system using experimental motion data from four healthy subjects. The torques were estimated by applying our previous finding that only 6 (6-DOFs) out of 12-DOFs in the lower limbs need to be actuated to facilitate stable standing. Furthermore, it was shown that six cases of 6-DOFs exist, which facilitate stable standing. In order to characterize each of these cases in terms of the torque generation patterns and to identify a potential optimal 6-DOF combination, the joint torques during perturbations in eight different directions were estimated for all six cases of 6-DOFs. The results suggest that the actuation of both ankle flexion∕extension, both knee flexion∕extension, one hip flexion∕extension, and one hip abduction∕adduction DOF will result in the minimum torque requirements to regulate balance during perturbed standing. To facilitate unsupported FES-assisted standing, it is sufficient to actuate only 6-DOFs. An optimal combination of 6-DOFs exists, for which this system can generate able-bodied kinematics while requiring lower limb joint torques that are producible using contemporary FES technology. These findings suggest that FES-assisted arm-free standing of paraplegics is theoretically feasible, even when limited by the fact that muscles actuating specific DOFs are often denervated or difficult to access.

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