IDENTIFICATION OF THE NONLINEAR FRICTION CHARACTERISTICS IN A HYDRAULIC ACTUATOR USING THE EXTENDED KALMAN FILTER

2008 ◽  
Vol 32 (2) ◽  
pp. 121-136 ◽  
Author(s):  
Yuvin Chinniah ◽  
Richard Burton ◽  
Saeid Habibi ◽  
Eric Sampson
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Quadratic Function ◽  
Friction Model ◽  
Nonlinear Friction ◽  
Hydraulic Actuator ◽  
Friction Characteristic ◽  
Piston Velocity ◽  
Friction Characteristics ◽  
Custom Made

In this paper, the nonlinear friction characteristic of a custom made symmetrical linear hydraulic actuator is investigated using the Extended Kalman Filter (EKF). A new and very accurate characterization of friction is made by using a quadratic function of the piston velocity. Further to this proposed empirical friction model, the EKF is used to estimate the function coefficients. In this paper, an iterative approach is used to maintain system observability and render the estimation process more reliable. The study is conducted in simulation and by using measured experimental data. The estimated states and parameters by the EKF are found to be convergent to their known values in simulation and, further to experimental results, unique and repeatable. In addition, changes in the friction characteristics, which can occur in the physical system due to wear in the piston seals or degradation in the oil properties, are detected and accurately estimated by the EKF in simulation. This study presents an accurate nonlinear model for the representation of friction in a hydraulic actuator. It paves the way for the implementation of strategies for early fault detection in hydraulic systems.

scholarly journals Nonlinear Friction and Dynamical Identification for a Robot Manipulator with Improved Cuckoo Search Algorithm

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Li Ding ◽  
Xingcheng Li ◽  
Qilin Li ◽  
Yuan Chao
Keyword(s):  
Robot Manipulator ◽  
Search Algorithm ◽  
Cuckoo Search ◽  
Cuckoo Search Algorithm ◽  
Friction Model ◽  
Nonlinear Friction ◽  
Friction Characteristic ◽  
Original Algorithm ◽  
Chaotic Operator ◽  
Improved Cuckoo Search Algorithm

This paper concerns the problem of dynamical identification for an industrial robot manipulator and presents an identification procedure based on an improved cuckoo search algorithm. Firstly, a dynamical model of a 6-DOF industrial serial robot has been derived. And a nonlinear friction model is added to describe the friction characteristic at motion reversal. Secondly, we use a cuckoo search algorithm to identify the unknown parameters. To enhance the performance of the original algorithm, both chaotic operator and emotion operator are employed to help the algorithm jump out of local optimum. Then, the proposed algorithm has been implemented on the first three joints of the ER-16 robot manipulator through an identification experiment. The results show that (1) the proposed algorithm has higher identification accuracy over the cuckoo search algorithm or particle swarm optimization algorithm and (2) compared to linear friction model the nonlinear model can describe the friction characteristic of joints better.

Noise Attenuation in a Secondary Controlled Electro-Hydraulic Actuator Using an Extended Kalman Filter

2021 ◽  
Author(s):  
Niklas Simonsen ◽  
Emil Munk Sørensen ◽  
Mikkel van Binsbergen-Galán ◽  
Stine Flindt Hornemann Kleine ◽  
Mikkel Hvid Nielsen ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Speed Control ◽  
Limiting Factor ◽  
Primary Control ◽  
Variable Speed ◽  
Hydraulic Actuator ◽  
Secondary Control ◽  
Control Approach ◽  
The Impact

Abstract Conventionally, variable-speed electro-hydraulic linear actuators utilize the speed control loops of electric machines and associated drives to control the pump flows, thereby realizing primary control functions. An alternative control approach is secondary control, which realizes a pressure coupling between the motor/pump and cylinder via the electromagnetic motor torque, with a flow reaction. Secondary controls in such drives has theoretically been shown to enable significantly higher control band-widths compared to primary control approaches. The theoretical bandwidth improvement is possible as the secondary control approach utilizes the faster dynamics of the electric machine, whereas the primary control approach revolves about the slower hydraulic dynamics present in the speed control loop. This paper considers the design and implementation of a secondary control function in a variable-speed electro-hydraulic actuator test bench, in order to validate the properties of such controls. Initial results show that the proposed secondary control approach is highly sensitive to measurement noise, which proves to be a limiting factor for the achievable control bandwidth, if smooth operation of the system is to be maintained. To attenuate the noise impact an extended Kalman filter is proposed in conjunction with the secondary control approach. Results demonstrate that the inclusion of the extended Kalman filter significantly reduces the impact of signal noise on the internal drive states, thereby enabling increased bandwidth and expanding the application range for this control method.

Extended Kalman Filter for Vehicle Suspension System

2014 ◽  
Vol 573 ◽  
pp. 317-321 ◽  
Author(s):  
K. Rajeswari ◽  
Anjali
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Ride Comfort ◽  
Active Suspension ◽  
Measurement Model ◽  
Suspension System ◽  
Vertical Acceleration ◽  
Hydraulic Actuator ◽  
Actuator Dynamics ◽  
Vehicle Suspension System

This paper presents an estimator for a nonlinear active suspension system considering the hydraulic actuator dynamics. PID controller is used to control the Active suspension system of nonlinear quarter car model. Extended Kalman filter is designed to estimate the states from the measurement model perturbed with noise. Simulation results demonstrate the effectiveness of the PID based active suspension system in reducing the vertical acceleration transmitted to the passengers thereby improving the ride comfort. Also the effectiveness of the Extended Kalman filter in estimating the actual vehicle states is demonstrated.

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