scholarly journals Central pattern generator–based coupling control method for synchronously controlling the two-degrees-of-freedom robot

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987773
Author(s):  
Qiang Fu ◽  
Tianhong Luo ◽  
Chunpeng Pan ◽  
Guoguo Wu
Keyword(s):  
Central Pattern Generator ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Coupling Parameter ◽  
Pattern Generator ◽  
Rhythmic Pattern ◽  
Motion Pattern ◽  
Two Degrees Of Freedom ◽  
Synchronous Control ◽  
Real Time Simulations

Synchronous control is a fundamental and significant problem for controlling a multi-joint robot. In this article, by applying two coupled Rayleigh oscillators as the referred central pattern generator models for the two joints of a two-degrees-of-freedom robot, the central pattern generator–based coupling control method is proposed for controlling the two-degrees-of-freedom robot’s joints. On these bases, the co-simulation model of the two-degrees-of-freedom robot with the proposed central pattern generator–based coupling control method is established via ADAMS and MATLAB/Simulink, and the performance of the central pattern generator–based coupling control method on synchronizing two motions of two-degrees-of-freedom robot’s joints is numerically simulated. Furthermore, the experimental setup of a two-degrees-of-freedom robot is established based on the real-time simulations system via the proposed central pattern generator–based coupling control method. And experiments are carried out on the established setup. Simulations and experimental results show that the phase of the controlled two-degrees-of-freedom robot’s joints is mutual locked to other, and their motion pattern can be adjusted through the coupling parameter in the central pattern generator–based coupling control method. In conclusion, the proposed central pattern generator–based coupling control method can control the two-degrees-of-freedom robot’s joints to produce the coordinated motions and adjust the rhythmic pattern of the two-degrees-of-freedom robot.

scholarly journals Torque Ripple Suppression of PMSM Based on Robust Two Degrees-of-Freedom Resonant Controller

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1015
Author(s):  
Mingfei Huang ◽  
Yongting Deng ◽  
Hongwen Li ◽  
Jing Liu ◽  
Meng Shao ◽  
...  
Keyword(s):  
Control Strategy ◽  
Measurement Errors ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Torque Ripple ◽  
Current Loop ◽  
Two Degrees Of Freedom ◽  
Robust Stability Analysis ◽  
Resonant Controller ◽  
Testing Environments

This paper concentrates on a robust resonant control strategy of a permanent magnet synchronous motor (PMSM) for electric drivers with model uncertainties and external disturbances to improve the control performance of the current loop. Firstly, to reduce the torque ripple of PMSM, the resonant controller with fractional order (FO) calculus is introduced. Then, a robust two degrees-of-freedom (Robust-TDOF) control strategy was designed based on the modified resonant controller. Finally, by combining the two control methods, this study proposes an enhanced Robust-TDOF regulation method, named as the robust two degrees-of-freedom resonant controller (Robust-TDOFR), to guarantee the robustness of model uncertainty and to further improve the performance with minimized periodic torque ripples. Meanwhile, a tuning method was constructed followed by stability and robust stability analysis. Furthermore, the proposed Robust-TDOFR control method was applied in the current loop of a PMSM to suppress the periodic current harmonics caused by non-ideal factors of inverter and current measurement errors. Finally, simulations and experiments were performed to validate our control strategy. The simulation and experimental results showed that the THDs (total harmonic distortion) of phase current decreased to a level of 0.69% and 5.79% in the two testing environments.

scholarly journals Flatness-Based Control of a Two Degrees-of-Freedom Platform With Pneumatic Artificial Muscles

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
David Bou Saba ◽  
Paolo Massioni ◽  
Eric Bideaux ◽  
Xavier Brun
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Sliding Mode ◽  
Feedforward Control ◽  
Volume Ratio ◽  
Open Loop ◽  
Control Technique ◽  
Artificial Muscles ◽  
Two Degrees Of Freedom ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are an interesting type of actuators as they provide high power-to-weight and power-to-volume ratio. However, their efficient use requires very accurate control methods taking into account their complex and nonlinear dynamics. This paper considers a two degrees-of-freedom platform whose attitude is determined by three pneumatic muscles controlled by servovalves. An overactuation is present as three muscles are controlled for only two degrees-of-freedom. The contribution of this work is twofold. First, whereas most of the literature approaches the control of systems of similar nature with sliding mode control, we show that the platform can be controlled with the flatness-based approach. This method is a nonlinear open-loop controller. In addition, this approach is model-based, and it can be applied thanks to the accurate models of the muscles, the platform and the servovalves, experimentally developed. In addition to the flatness-based controller, which is mainly a feedforward control, a proportional-integral (PI) controller is added in order to overcome the modeling errors and to improve the control robustness. Second, we solve the overactuation of the platform by an adequate choice for the range of the efforts applied by the muscles. In this paper, we recall the basics of this control technique and then show how it is applied to the proposed experimental platform. At the end of the paper, the proposed approach is compared to the most commonly used control method, and its effectiveness is shown by means of experimental results.

scholarly journals Trajectory tracking control of two degrees-of-freedom helicopter based on Udwadia–Kalaba theory

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401880893
Author(s):  
Yinfei Zhu ◽  
Han Zhao ◽  
Hao Sun ◽  
Kang Huang ◽  
Yinghui Dong
Keyword(s):  
Trajectory Tracking ◽  
Tracking Control ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Initial Conditions ◽  
Control Cost ◽  
Trajectory Tracking Control ◽  
Constraint Force ◽  
Two Degrees Of Freedom ◽  
High Control

In this article, by using Lagrange energy method, we establish the dynamical model of a two degrees-of-freedom helicopter, which is subject to holonomic constraints. A control method based on Udwadia–Kalaba theory is proposed to achieve the trajectory tracking control of the 2-degrees-of-freedom helicopter. Different from traditional methods, this method could solve the constraint force of the mechanical system without adding additional parameters such as Lagrange multipliers. When initial conditions are compatible, we can use the nominal control which is based on Udwadia–Kalaba equation to control 2-degrees-of-freedom helicopter in real time. But when initial conditions have incompatibility, the simulation result could produce divergence phenomenon. To solve the trajectory tracking control problem of 2-degrees-of-freedom helicopter under incompatible initial conditions, a modified controller is proposed. We also make simulation contrast by different control methods to validate the effectiveness and superiority of the modified controller. Simulation results show that the modified controller can drive the 2-degrees-of-freedom helicopter to perfectly track the desired trajectory with less control cost and high control accuracy.

scholarly journals Gait Control of Hexapod Robot Based on Field-Programmable Gate Array and Central Pattern Generator

2020 ◽  
Vol 53 (6) ◽  
pp. 931-937
Author(s):  
Tianbo Qiao
Keyword(s):  
Central Pattern Generator ◽  
Field Programmable Gate Array ◽  
Control Method ◽  
Pattern Generator ◽  
Hexapod Robot ◽  
Gait Control ◽  
Field Programmable ◽  
Physical Prototype ◽  
Hardware Description ◽  
Gate Array

This paper attempts to improve the terrain adaptability of hexapod robot through gait control. Firstly, the multi-leg coupling in the tripodal gait of the hexapod robot was modeled by Hopf oscillator. Then, annular central pattern generator (CPG) was adopted to simulate the leg movements of hexapod robot between signals. Furthermore, a physical prototype was designed for the gait control test on field-programmable gate array (FPGA), and the algorithm of the rhythmic output of the model was programmed in Verilog, a hardware description language. Finally, the effectiveness of our gait control method was verified through the simulation on Xilinx. The results show that the phase difference of the CPG network remained stable; the designed hexapod robot moved at about 5.15cm/s stably in a tripodal gait, and outperformed wheeled and tracked robots in terrain adaptation. The research findings lay a solid basis for the design of all-terrain multi-leg robots.

scholarly journals The locust frontal ganglion: a central pattern generator network controlling foregut rhythmic motor patterns

2002 ◽  
Vol 205 (18) ◽  
pp. 2825-2832 ◽  
Author(s):  
Amir Ayali ◽  
Yael Zilberstein ◽  
Netta Cohen
Keyword(s):  
Central Pattern Generator ◽  
Schistocerca Gregaria ◽  
Physiological State ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Rhythmic Pattern ◽  
Stomatogastric Nervous System ◽  
Motor Patterns ◽  
Frontal Ganglion

SUMMARYThe frontal ganglion (FG) is part of the insect stomatogastric nervous system and is found in most insect orders. Previous work has shown that in the desert locust, Schistocerca gregaria, the FG constitutes a major source of innervation to the foregut. In an in vitro preparation,isolated from all descending and sensory inputs, the FG spontaneously generated rhythmic multi-unit bursts of action potentials that could be recorded from all its efferent nerves. The consistent endogenous FG rhythmic pattern indicates the presence of a central pattern generator network. We found the appearance of in vitro rhythmic activity to be strongly correlated with the physiological state of the donor locust. A robust pattern emerged only after a period of saline superfusion, if the locust had a very full foregut and crop, or if the animal was close to ecdysis. Accordingly,haemolymph collected at these stages inhibited an ongoing rhythmic pattern when applied onto the ganglion. We present this novel central pattern generating system as a basis for future work on the neural network characterisation and its role in generating and controlling behaviour.

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