Switching Gaussian Process Dynamic Models for simultaneous composite motion tracking and recognition

Author(s):  
Jixu Chen ◽  
Minyoung Kim ◽  
Yu Wang ◽  
Qiang Ji
2018 ◽  
Vol 95 (1) ◽  
pp. 217-237 ◽  
Author(s):  
Matt Bender ◽  
Li Tian ◽  
Xiaozhou Fan ◽  
Andrew Kurdila ◽  
Rolf Müller

2014 ◽  
Vol 67 (4) ◽  
pp. 603-615 ◽  
Author(s):  
Hongmei Chen ◽  
Xianghong Cheng ◽  
Haipeng Wang ◽  
Xu Han

Gaussian process regression (GPR) is used in a Spare-grid Quadrature Kalman filter (SGQKF) for Strap-down Inertial Navigation System (SINS)/odometer integrated navigation to bridge uncertain observation outages and maintain an estimate of the evolving SINS biases. The SGQKF uses nonlinearized dynamic models with complex stochastic nonlinearities so the performance degrades significantly during observation outages owing to the uncertainties and noise. The GPR calculates the residual output after factoring in the contributions of the parametric model that is used as a nonlinear SINS error predictor integrated into the SGQKF. The sensor measurements and SINS output deviations from the odometer are collected in a data set during observation availability. The GPR is then applied to predict SINS deviations from the odometer and then the predicted SINS deviations are fed to the SGQKF as an actual update to estimate all SINS biases during observation outages. We demonstrate our method's effectiveness in bridging uncertain observation outages in simulations and in real road tests. The results agree with the theoretical analysis, which demonstrate that SGQKF using GPR can maintain an estimate of the evolving SINS biases during signal outages.


Author(s):  
Niki Aifanti ◽  
Angel D. Sappa ◽  
Nikos Grammalidis ◽  
Sotiris Malassiotis

Tracking and recognition of human motion has become an important research area in computer vision. In real-world conditions it constitutes a complicated problem, considering cluttered backgrounds, gross illumination variations, occlusions, self-occlusions, different clothing, and multiple moving objects. These ill-posed problems are usually tackled by simplifying assumptions regarding the scene or by imposing constraints on the motion. Constraints such as that the contrast between the moving people and the background should be high, and that everything in the scene should be static except for the target person, are quite often introduced in order to achieve accurate segmentation. Moreover, the motion of the target person is often confined to simple movements with limited occlusions. In addition, assumptions such as known initial position and posture of the person are usually imposed in tracking processes.


2021 ◽  
pp. 20-25
Author(s):  
VIKTOR I. BALABANOV ◽  

The working equipment used for deep loosening of heavy mechanical soils during the restoration of temporarily unclaimed agricultural lands includes a basic machine unit with attachments infl uenced by signifi cant oscillatory loads during its operation. The variability of the physical and mechanical properties of the treated soil aff ects the uneven depth of loosening and the machine operation. This is one of the main technological indicators evaluating the performance features of rippers. The research purpose is to analyze the ripper as a dynamic system and estimate the magnitude of the fl uctuations in the loosening depth depending on the surface irregularities of the machine’s path along the fi eld. The research was carried out according to generally accepted methods using modeling. The authors considered the functioning model of the reclamation ripper in the form of an “environment – machine – technological process” dynamic system, which converts input disturbances and control actions into output ones. The study results of reclamation ripper dynamic models have shown that average terrain irregularities of 5…10 cm result in the amplitude of cutting edge vibrations of a pneumatic-wheeled ripper equaling 8…15 cm and 6…12 cm for the ripper coupled with a caterpillar tractor. According to agrotechnical requirements, a loosening depth of 0.8 m results in the permissible deviations of 8 cm.


Author(s):  
Lasse Schmidt ◽  
Torben O. Andersen ◽  
Henrik C. Pedersen ◽  
Michael M. Bech

The dominant physical phenomena in hydraulic drives are generally well known, why the model equations describing the dominant dynamics may be established with a high level of certainty. To some extend, this is also the case for the model parameters when these are based on data sheet information. However, parameters such as the effective bulk modulus, leakage, external disturbances etc. may be difficult to evaluate, and may furthermore be varying. In regard to control design, linear methods may be difficult to apply and stability margins difficult to evaluate, unless dynamic models are established prior to the control design. This problem may be overcome using adaptive controllers, adjusting themselves to uncertainties/variations. This often shifts the problem from adjusting the controller parameters, to adjusting the parameters of the control parameter adaption mechanism, which in many cases involves a significant number of parameters. This paper considers a novel adaptive control algorithm, theoretically applicable to systems of arbitrary orders, and potentially only with three tuning parameters. The proposed algorithm is considered in relation to the position control of a hydraulic winch drive, and results imply that excellent motion tracking performance may be achieved utilizing only state feedback.


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