Experimental studies on robustness of a learning method with a forgetting factor for robotic motion control

Author(s):  
Y. Nanjo ◽  
S. Arimoto
2020 ◽  
Author(s):  
Kathryn E. Kirchoff ◽  
Shawn M. Gomez

AbstractKinase-catalyzed phosphorylation of proteins forms the backbone of signal transduction within the cell, enabling the coordination of numerous processes such as the cell cycle, apoptosis, and differentiation. While on the order of 105 phosphorylation events have been described, we know the specific kinase performing these functions for less than 5% of cases. The ability to predict which kinases initiate specific individual phosphorylation events has the potential to greatly enhance the design of downstream experimental studies, while simultaneously creating a preliminary map of the broader phosphorylation network that controls cellular signaling. To this end, we describe EMBER, a deep learning method that integrates kinase-phylogeny information and motif-dissimilarity information into a multi-label classification model for the prediction of kinase-motif phosphorylation events. Unlike previous deep learning methods that perform single-label classification, we restate the task of kinase-motif phosphorylation prediction as a multi-label problem, allowing us to train a single unified model rather than a separate model for each of the 134 kinase families. We utilize a Siamese network to generate novel vector representations, or an embedding, of motif sequences, and we compare our novel embedding to a previously proposed peptide embedding. Our motif vector representations are used, along with one-hot encoded motif sequences, as input to a classification network while also leveraging kinase phylogenetic relationships into our model via a kinase phylogeny-based loss function. Results suggest that this approach holds significant promise for improving our map of phosphorylation relations that underlie kinome signaling.Availabilityhttps://github.com/gomezlab/EMBER


Author(s):  
Shiuh-Jer Huang ◽  
Shian-Shin Wu ◽  
You-Min Huang

A Mitsubishi Movemaster RV-M2 robotic system control system is retrofitted into system-on-programmable-chip (SOPC) control structure. The software embedded in Altera Nios II field programmable gate array (FPGA) micro processor has the functions of using UART to communicate with PC, robotic inverse kinematics calculation, and robotic motion control. The digital hardware circuits with encoder decoding, limit switch detecting, pulse width modulation (PWM) generating functions are designed by using Verilog language. Since the robotic dynamics has complicate nonlinear behavior, it is impossible to design a MIMO model-based controller on micro-processor. Here a novel model-free fuzzy sliding mode control with gain scheduling strategy is developed to design the robotic joint controller. This fuzzy controller is easy to implement with 1D fuzzy control rule and less trial-and-error parameters searching work. The experimental results show that this intelligent controller can achieve quick transient response and precise steady state accuracy for industrial applications.


2007 ◽  
Vol 04 (03) ◽  
pp. 237-249
Author(s):  
MIN WANG ◽  
XIADONG LV ◽  
XINHAN HUANG

This paper presents a vision based motion control and trajectory tracking strategies for microassembly robots including a self-optimizing visual servoing depth motion control method and a novel trajectory snake tracking strategy. To measure micromanipulator depth motion, a normalized gray-variance focus measure operator is developed using depth from focus techniques. The extracted defocus features are theoretically distributed with one peak point which can be applied to locate the microscopic focal depth via self-optimizing control. Tracking differentiators are developed to suppress noises and track the features and their differential values without oscillation. Based on the differential defocus signals a coarse-to-fine self-optimizing controller is presented for micromanipulator to precisely locate focus depth. As well as a novel trajectory snake energy function of robotic motion is defined involving kinematic energy, curve potential and image potential energy. The motion trajectory can be located through searching the converged energy distribution of the snake function. Energy weights in the function are real-time adjusted to avoid local minima during convergence. To improve snake searching efficiency, quadratic-trajectory least square estimator is employed to predict manipulator motion position before tracking. Experimental results in a microassembly robotic system demonstrate that the proposed strategies are successful and effective.


ISRN Robotics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Maurizio Melluso

A new fuzzy adaptive control is applied to solve a problem of motion control of nonholonomic vehicles with two independent wheels actuated by a differential drive. The major objective of this work is to obtain a motion control system by using a new fuzzy inference mechanism where the Lyapunov stability can be ensured. In particular the parameters of the kinematical control law are obtained using a fuzzy mechanism, where the properties of the fuzzy maps have been established to have the stability above. Due to the nonlinear map of the intelligent fuzzy inference mechanism (i.e., fuzzy rules and value of the rule), the parameters above are not constant, but, time after time, based on empirical fuzzy rules, they are updated in function of the values of the tracking errors. Since the fuzzy maps are adjusted based on the control performances, the parameters updating ensures a robustness and fast convergence of the tracking errors. Also, since the vehicle dynamics and kinematics can be completely unknown, dynamical and kinematical adaptive controllers have been added. The proposed fuzzy controller has been implemented for a real nonholonomic electrical vehicle. Therefore, system robustness and stability performance are verified through simulations and experimental studies.


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