Acceleration tracking performance improvement of multi-dof shaker

Gain tuning is very important in order to obtain good performances for a given controller. Contour tracking performance is mainly determined by the selected control gains of a position domain PID controller. In this paper, three popular evolutionary algorithms are utilized to optimize the gains of a position domain PID controller for performance improvement of contour tracking of robotic manipulators. Differential Evolution (DE), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO) are used to determine the optimal gains of the position domain PID controller, and three distinct fitness functions are also used to quantify the contour tracking performance of each solution set. Simulation results show that DE features the highest performance indexes for both linear and nonlinear contour tracking, while PSO is quite efficient for linear contour tracking. Both algorithms performed consistently better than GA that featured premature convergence in all cases.

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On an evaluation of tracking performance improvement by SMC-PHD filter with intensity image of pedestrians detection over on-board camera using neural network

2014 World Automation Congress (WAC) ◽

10.1109/wac.2014.6935886 ◽

2014 ◽

Author(s):

Norikazu Ikoma ◽

Yuuki Haraguchi ◽

Hiromu Hasegawa

Keyword(s):

Neural Network ◽

Performance Improvement ◽

Tracking Performance ◽

Intensity Image

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A Novel Virtual Sensor for Estimating Robot Joint Total Friction Based on Total Momentum

Applied Sciences ◽

10.3390/app9163344 ◽

2019 ◽

Vol 9 (16) ◽

pp. 3344 ◽

Cited By ~ 2

Author(s):

Xu ◽

Fan ◽

Fang ◽

Wang ◽

Zhu ◽

...

Keyword(s):

Performance Improvement ◽

Trajectory Tracking ◽

Friction Model ◽

Friction Torque ◽

Joint Torque ◽

Tracking Performance ◽

Step Response ◽

Virtual Sensor ◽

Joint Friction ◽

Velocity Tracking

Robot joint friction is an important and complicated issue in improving robot control performance. In this paper, a virtual sensor based on the total generalized momentum concept is proposed to estimate the total friction torque, including both the motor-side and link-side friction, of robot joints without joint torque sensors. The proposed algorithm only requires a robot joint dynamics model and not a complex friction model dependent on factors such as time and velocity. By compensating for the estimated friction torque with a robot joint controller, the trajectory tracking performance of the controller, especially the velocity tracking performance, can be improved. To verify the effectiveness of the developed algorithm, 2-DOF planar manipulator simulations and single-joint system experiments are conducted. The simulation and experimental results show that the designed virtual sensor can effectively estimate the total joint friction disturbance and that the controller trajectory tracking performance is improved after observed friction compensation. However, the position tracking performance improvement of the controller is less than that for the velocity tracking performance improvement during the experiments. In addition, the velocity step response ability and velocity tracking performance of the controller are improved more at low velocities than that at high velocities in the experiments. The proposed algorithm has engineering and theoretical significance for estimating robot joint friction and improving the performance of robot joint controllers.

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Acceleration decoupling control of 6 degrees of freedom electro-hydraulic shaking table

Journal of Vibration and Control ◽

10.1177/1077546319870620 ◽

2019 ◽

Vol 25 (21-22) ◽

pp. 2758-2768 ◽

Cited By ~ 2

Author(s):

Guang-feng Guan ◽

AR Plummer

Keyword(s):

Degrees Of Freedom ◽

Inverse Dynamics ◽

Joint Space ◽

Decoupling Control ◽

Shaking Table ◽

Tracking Performance ◽

Actuator Dynamics ◽

Stability Margins ◽

Seismic Testing ◽

Acceleration Tracking

Electro-hydraulic shaking tables are widely used for vibration testing where high force and displacement amplitudes are required. In particular, they are a vital tool in seismic testing, enabling the development of buildings and other structures which are earthquake resistant. Three-variable-control (TVC) is commonly used for the control of multi-degrees of freedom (DOFs) electro-hydraulic shaking tables. However, the coupling between the DOFs is often significant and is not compensated by TVC. In this paper, an acceleration decoupling control (ADC) method is presented for a 6 DOFs electro-hydraulic shaking table system to improve the acceleration tracking performance and decouple the motion in task space. The gravitational, Coriolis, and centripetal forces are compensated for in joint space based on a dynamic model of the shaking table. Modal control is used to transform the coupled dynamics into six independent systems. Inverse dynamics models are used to cancel the differences in actuator dynamics. The proportional gains in modal space are tuned heuristically to give sufficient stability margins to provide robustness in the presence of modeling errors. The input filter and feedforward controller in TVC are added to improve the acceleration tracking performance of each independent system. Experimental acceleration frequency responses are used to demonstrate the effectiveness of ADC, and in particular these show a consistent reduction in cross-axis coupling compared to TVC. Moreover, only four parameters need to be tuned, as opposed to 36 for TVC, and the method provides a viable route to improving the accuracy of seismic testing in the future.

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