scholarly journals Feedback Linearization of Inertially Actuated Jumping Robots

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 114
Author(s):  
Adam Cox ◽  
Pouria Razzaghi ◽  
Yildirim Hurmuzlu
Keyword(s):  
Feedback Linearization ◽  
Experimental Results ◽  
Family Tree ◽  
Ground Contact ◽  
Jump Height ◽  
3 Dimensional ◽  
Hybrid Nature ◽  
Design Paradigm ◽  
Motion Complexity ◽  
Research Studies

Inertially Actuated Jumping Robots (IAJR) provide a promising new means of locomotion. The difficulty of IAJR is found in the hybrid nature of the ground contact/flying dynamics. Recent research studies in our Systems Lab have provided a family tree of inertially actuated locomotion systems. The proposed Tapping Robot is the most prompt member of this tree. In this paper, a feedback linearization controller is introduced to provide controllability given the 3-dimensional motion complexity. The research objective is to create a general controller that can regulate the locomotion of Inertially Actuated Jumping Robots. The expected results can specify a desired speed and/or jump height, and the controller ensures the desired values are achieved. The controller can achieve the greatest response for the Basketball Robot at a maximum jump height of 0.25 m, which is greater than the former performance with approximately 0.18 m. The design paradigm used on the Basketball Robot was extended to the Tapping Robot. The Tapping Robot achieved a stable average forward velocity of 0.0773 m/s in simulation and 0.157 m/s in experimental results, which is faster than the forward velocity of former robot, Pony III, with 0.045 m/s.

Single-Leg Jump Performance Before and After Exercise in Healthy and Anterior Cruciate Ligament Reconstructed Individuals

2020 ◽  
Vol 29 (7) ◽  
pp. 879-885
Author(s):  
Haley Bookbinder ◽  
Lindsay V. Slater ◽  
Austin Simpson ◽  
Jay Hertel ◽  
Joseph M. Hart
Keyword(s):  
Anterior Cruciate Ligament ◽  
Repeated Measures ◽  
Contact Time ◽  
Cruciate Ligament ◽  
Ground Contact ◽  
Jump Height ◽  
Before And After ◽  
Healthy Control ◽  
Ground Contact Time ◽  
Anterior Cruciate

Context: Many clinicians measure lower-extremity symmetry after anterior cruciate ligament reconstruction (ACLR); however, testing is completed in a rested state rather than postexercise. Testing postexercise may better model conditions under which injury occurs. Objective: To compare changes in single-leg performance in healthy and individuals with history of ACLR before and after exercise. Design: Repeated-measures case-control. Setting: Laboratory. Patients: Fifty-two subjects (25 control and 27 ACLR). Intervention: Thirty minutes of exercise. Main Outcome Measures: Limb symmetry and involved limb performance (nondominant for healthy) for single-leg hop, ground contact time, and jump height during the 4-jump test. Cohen d effect sizes were calculated for all differences identified using a repeated-measures analysis of variance. Results: Healthy controls hopped farther than ACLR before (d = 0.65; confidence interval [CI], 0.09 to 1.20) and after exercise (d = 0.60; CI, 0.04 to 1.15). Those with ACLR had longer ground contact time on the reconstructed limb compared with the uninvolved limb after exercise (d = 0.53; CI, −0.02 to 1.09), and the reconstructed limb had greater ground contact time compared with the healthy control limb after exercise (d = 0.38; CI, −0.21 to 0.73). ACLR were less symmetrical than healthy before (d = 0.38; CI, 0.17 to 0.93) and after exercise (d = 0.84; CI, 0.28 to 1.41), and the reconstructed limb demonstrated decreased jump height compared with the healthy control limbs before (d = 0.75; CI, 0.19 to 1.31) and after exercise (d = 0.79; CI, 0.23 to 1.36). Conclusions: ACLR became more symmetric, which may be from adaptations of the reconstructed limb after exercise. Changes in performance and symmetry may provide additional information regarding adaptations to exercise after reconstruction.

scholarly journals sEMG-Based Neural Network Prediction Model Selection of Gesture Fatigue and Dataset Optimization

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Fujun Ma ◽  
Fanghao Song ◽  
Yan Liu ◽  
Jiahui Niu
Keyword(s):  
Neural Network ◽  
Energy Consumption ◽  
Prediction Model ◽  
Mean Square Error ◽  
Short Term Memory ◽  
Experimental Results ◽  
Support Vector ◽  
Mean Square ◽  
Semg Signals ◽  
Research Studies

The fatigue energy consumption of independent gestures can be obtained by calculating the power spectrum of surface electromyography (sEMG) signals. The existing research studies focus on the fatigue of independent gestures, while the research studies on integrated gestures are few. However, the actual gesture operation mode is usually integrated by multiple independent gestures, so the fatigue degree of integrated gestures can be predicted by training neural network of independent gestures. Three natural gestures including browsing information, playing games, and typing are divided into nine independent gestures in this paper, and the predicted model is established and trained by calculating the energy consumption of independent gestures. The artificial neural networks (ANNs) including backpropagation (BP) neural network, recurrent neural network (RNN), and long short-term memory (LSTM) are used to predict the fatigue of gesture. The support vector machine (SVM) is used to assist verification. Mean square error (MSE), root mean square error (RMSE), and mean absolute error (MAE) are utilized to evaluate the optimal prediction model. Furthermore, the different datasets of the processed sEMG signal and its decomposed wavelet coefficients are trained, respectively, and the changes of error functions of them are compared. The experimental results show that LSTM model is more suitable for gesture fatigue prediction. The processed sEMG signals are appropriate for using as the training set the fatigue degree of one-handed gesture. It is better to use wavelet decomposition coefficients as datasets to predict the high-dimensional sEMG signals of two-handed gestures. The experimental results can be applied to predict the fatigue degree of complex human-machine interactive gestures, help to avoid unreasonable gestures, and improve the user’s interactive experience.

A Novel CBCD Method Based on 3-Dimensional SIFT Descriptors in Dynamic Tunnels

2012 ◽  
Vol 236-237 ◽  
pp. 1072-1077
Author(s):  
Jie Hou ◽  
Bao Long Guo
Keyword(s):  
Computational Cost ◽  
Research Area ◽  
Experimental Results ◽  
Copy Detection ◽  
3 Dimensional ◽  
Proper Balance

Content-Based Copy Detection (CBCD) is a heated research area. A variety of features are extracted and applied extensively to improve the performance of CBCD systems. A novel scheme which adopts 3-Dimensional SIFT Descriptors (Paul Scavenger, 2007) based on the innovative dynamic tunnels is proposed in this paper. The algorithm is aim to reach a proper balance between efficiency and accuracy. Experimental results indicate that the algorithm achieves an accuracy match with inexpensive computational cost.

A 3-Dimensional Body Fitted Simulation of Heat and Mass Transfer in Rice Kernel during Hot Air Drying Process

2019 ◽  
Vol 15 (3-4) ◽  
Author(s):  
Lijuan Zhao ◽  
Junhong Yang ◽  
Tengfei Du ◽  
Zhonghua Wu
Keyword(s):  
Moisture Content ◽  
Three Dimensional ◽  
Brown Rice ◽  
Experimental Results ◽  
Maximum Deviation ◽  
Drying Process ◽  
3 Dimensional ◽  
Geometry Model ◽  
Hot Air ◽  
Main Factor

AbstractA precise geometry model of the rice kernel is necessary to predict the moisture content and temperature distribution, or even drying stress in the kernel. In this study, a three-dimensional body fitted model of brown rice (Chunyou 84) kernel was developed by using image processing method, and the COMSOL Multiphysics software was used to simulate the drying process of the brown rice and compared with the experimental results. The maximum deviation between the simulated and experimental results was about 8%. During the drying process, the temperature gradient in the rice kernel only occurred a few minutes at the initial drying period (0–6.5 min, at 45 °C), while the moisture content gradient lasted in the whole drying process. Simulation and experimental results showed that the hot air temperature was one main factor governing the drying process of the brown rice.

scholarly journals Experimental Evaluation of the Accuracy of Biped Model to Predict the Kinematics during Walking

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yao Zhang ◽  
Zhigang Song
Keyword(s):  
Experimental Evaluation ◽  
Sports Medicine ◽  
Experimental Results ◽  
Structural Vibration ◽  
Inertial Measurement Units ◽  
Step Frequency ◽  
Engineering Applications ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Research Studies

Biped models (BMs) have extensive applications in structural vibration, robotics, and sports medicine, but the differences between the walking kinematics simulated by the BM model and those measured through an experiment have not been comprehensively recognized. This paper used wireless inertial measurement units (IMUs) to monitor the acceleration of center of masses (COMs) of 6 volunteers walking under the conditions of natural and fixed-knee gait. The observations were compared with the simulations from two typical BMs and also with the measurements from former research studies. The results show that when the step frequency is lower than 2.0 Hz, the peaks of acceleration simulated by BM are close to those observed in experiments and the errors are acceptable, while the step frequency is higher than 2.0 Hz, the discrepancy between the numerical and the experimental results is increasingly larger with higher step frequencies, and the errors can reach 60% at most. The comparison between numerical and experimental results indicates that the knee-fixing assumption of BMs may lead to overestimating the peaks of accelerations, but this assumption fails to explain the different increasing rates with respect to step frequency. Further research studies about the accuracy of BMs and relative modification methods are expected for civil engineering applications.

A Comparative Analysis of Slip Factor on Impellers of Centrifugal Blower

2014 ◽  
Author(s):  
Beena D. Baloni ◽  
Bhushan Kumar ◽  
S. A. Channiwala
Keyword(s):  
Experimental Results ◽  
Centrifugal Blower ◽  
Pressure Transducers ◽  
3 Dimensional ◽  
Slip Factor ◽  
Impeller Outlet ◽  
Rotor Stator Interaction ◽  
Outlet Flow ◽  
And Performance ◽  
Insight Into

The Slip phenomenon strongly influences the working conditions and performance of turbomachines. It is of interest to know accurately the parameters influencing the slip factor and its effect on the turbomachines. The present work incorporates an experimental analysis of the slip factor for different types of impellers. The main purpose is to provide an insight into the effect of different blade exit angle on the slip factor. Therefore, a single stage centrifugal blower with three types of impellers viz. backward curved, backward curved with radial tipped and forward curved was developed for experimentation. A total of 12 test locations, at an interval of 30°, were selected near the impeller outlet regions. The volute of the blower was kept the same for all types of impellers. To analyze a 3-dimensional flow near the impeller region, a five hole probe is used. Pressure measured by a 5-hole probe was recorded with the help of pressure transducers. Experimental results indicate that, the slip factor was not constant at a whole impeller width as well as the impeller outlet radial periphery. The value and nature of the curve for the slip factor was different at all angular positions, along the width of the impeller. This may be due to the effect of rotor-stator interaction. The effect of rotor-stator interaction increases as we move from the tongue to the exit of the volute. This affects the impeller outlet flow at different angular positions. From the experimental results, it was observed that, the impeller outlet blade angle also has a significant effect on the slip factor. For the present case the value of the slip factor was the highest with the backward curved impeller and the lowest with the forward curved impeller.

A Hybrid Feedback Linearization and Neural Network Control Algorithm Applied to a Hydraulic Actuator

2016 ◽  
Author(s):  
Fabio A. P. Borges ◽  
Eduardo André Perondi ◽  
Mauro A. B. Cunha ◽  
Mario R. Sobczyk
Keyword(s):  
Neural Network ◽  
Feedback Linearization ◽  
Network Control ◽  
Experimental Results ◽  
Hydraulic Actuator ◽  
The Neural Network ◽  
Mechanical Subsystem ◽  
Network Functions ◽  
Compensation Approach ◽  
Feedback Linearization Approach

This paper report a research investigation that proposes to replace the inversion set present in the traditional feedback linearization approach by an artificial neural network resulting in a hybrid composition approach with a neural network and an analytical term. The method is applied into a hydraulic actuator position system together with a friction compensation approach also built using neural networks. The control strategy used is based on a cascade methodology that consists of interpreting the hydraulic positioning system model as two interconnected subsystems: a mechanical subsystem driven by a hydraulic one. As experimental results have indicated a significant system behavior dependence on the oil temperature, its effects are also studied and the proposed method was improved by the inclusion of the oil temperature information as an input for the neural network functions. Experimental results show the effectiveness of the proposed controller and their advantages when compared with the traditional analytical schemes with feedback linearization approaches.

Numerical and Experimental Investigations of Rotating Wheel Aerodynamics on the DrivAer Model With Engine Bay Flow

2017 ◽  
Author(s):  
Lukas Haag ◽  
Marco Kiewat ◽  
Thomas Indinger ◽  
Thomas Blacha
Keyword(s):  
Turbulence Model ◽  
Experimental Results ◽  
Ground Contact ◽  
Detached Eddy Simulation ◽  
Cfd Simulations ◽  
Sliding Mesh ◽  
Wheel Rotation ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Mesh Method

Wheel design and wheel rotation have been identified to be key factors influencing the overall aerodynamic performance of passenger cars. Hence, wheel aerodynamics has been the topic of various studies over the past few years. Recently, vehicle manufacturers have moved towards time-resolving CFD simulation methods. Therefore, a trend towards resembling the physical effect of wheel rotation by utilizing the Sliding Mesh Method can be observed in academia and the industry. The first part of the presented paper shows the results of CFD simulations using the Sliding Mesh Method on two generic test cases employing the Delayed Detached Eddy Simulation turbulence model. A rotating cylinder is investigated as well as a rotating wheel geometry, both in ground contact and lifted from the ground. The results show dependencies on the solution algorithm and the background turbulence model applied within the RANS region of the Delayed Detached Eddy Simulation model. The prediction accuracy of the CFD setup is assessed by comparing the results to experimental results on the rotating wheel geometry with ground contact obtained in a model scale wind tunnel. The second part of the paper focuses on the influence of the rim design on the aerodynamics of a full vehicle. Four rim geometries are investigated regarding their aerodynamic influence on the DrivAer reference body by CFD simulations using the Sliding Mesh Method. The DrivAer has recently been updated to include an engine bay geometry. This new version of the DrivAer is used for the presented study because the engine bay flow is expected to have a considerable influence especially on the flow around the front wheels. The simulation results are compared to experimental results obtained on a 1:2.5 scale model of the DrivAer with engine bay flow and are in good agreement.

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