A Model-Free Fine Position Control Method Using the Base-Sensor: With Application to a Hydraulic Manipulator

1997 ◽  
Vol 30 (20) ◽  
pp. 339-345
Author(s):  
Karl Iagnemma ◽  
Guillaume Morel ◽  
Steven Dubowsky
2008 ◽  
Vol 59 ◽  
pp. 178-183 ◽  
Author(s):  
Yuji Takeda ◽  
Hiroki Cho ◽  
Takaei Yamamoto ◽  
Toshio Sakuma ◽  
Akihiko Suzuki

The actuators using shape memory alloys can work as an actuator to control or retain positioning without using sensor devices. In this work, a position control model with a biasing mechanism is produced. The produced model is controlled by resistance feedback using the method of setting off-time and can be set and retained at an arbitrary position. The effects of input current, control distance and off-time on positioning characteristics such as dynamic behavior and position stability are investigated. The results show that high input current for heating is effective for shortening the rise and settling times. However, the overshoot increases with increasing input current. When the recovery strain is below 2.5%, the rise and settling velocities increase with increasing control distance. Furthermore, the off-time affects position stability. In the case of short off-time, fine position stability is performed regardless of the values of input current and control distance.


2020 ◽  
Vol 10 (8) ◽  
pp. 2755
Author(s):  
Fang Peng ◽  
Haiyang Wen ◽  
Cheng Zhang ◽  
Bugong Xu ◽  
Jiehao Li ◽  
...  

Active prosthetic knees (APKs) are widely used in the past decades. However, it is still challenging to make them more natural and controllable because: (1) most existing APKs that use rigid actuators have difficulty obtaining more natural walking; and (2) traditional finite-state impedance control has difficulty adjusting parameters for different motions and users. In this paper, a flexible APK with a compact variable stiffness actuator (VSA) is designed for obtaining more flexible bionic characteristics. The VSA joint is implemented by two motors of different sizes, which connect the knee angle and the joint stiffness. Considering the complexity of prothetic lower limb control due to unknown APK dynamics, as well as strong coupling between biological joints and prosthetic joints, an adaptive robust force/position control method is designed for generating a desired gait trajectory of the prosthesis. It can operate without the explicit model of the system dynamics and multiple tuning parameters of different gaits. The proposed model-free scheme utilizes the time-delay estimation technique, sliding mode control, and fuzzy neural network to realize finite-time convergence and gait trajectory tracking. The virtual prototype of APK was established in ADAMS as a testing platform and compared with two traditional time-delay control schemes. Some demonstrations are illustrated, which show that the proposed method has superior tracking characteristics and stronger robustness under uncertain disturbances within the trajectory error in ± 0 . 5 degrees. The VSA joint can reduce energy consumption by adjusting stiffness appropriately. Furthermore, the feasibility of this method was verified in a human–machine hybrid control model.


Author(s):  
Xichang Liang ◽  
Yi Wan ◽  
Chengrui Zhang ◽  
Yanyun Kou ◽  
Qianqian Xin ◽  
...  

A simple and robust tracking controller based on time delay estimation and nonsingular fast terminal sliding mode is proposed for the position control of hydraulic manipulator. The proposed controller does not require the mathematical model of hydraulic manipulator dynamics, which ensures that the method is simple and model free. Two elements, time delay estimation and nonsingular fast terminal sliding mode, are implemented in the proposed controller. Time delay estimation estimates the complex dynamics of the hydraulic manipulator, and nonsingular fast terminal sliding mode is implemented as the nonlinear desired error dynamic to ensure fast convergence and high trajectory tracking accuracy. Experiments are performed to verify the tracking performance of the method on a hydraulic manipulator. The results demonstrate that this method achieves faster and higher precision position tracking performance than a conventional time delay control with linear error dynamics.


2020 ◽  
Vol 53 (7-8) ◽  
pp. 1512-1517
Author(s):  
Wei Wang ◽  
Javed Masood Rana

This study uses a three-axis Gimbal model to inertially stabilize a platform that can be used to feed smooth images from a camera. In this article, three-axis Gimbal performance analysis is presented. An inertial measurement unit responds to movement and a three-phase brushless DC motor with 14 poles and 12 coils is used to rule out vibrations and movement from the surroundings. The controller combines sliding-mode control and model-free-adaptive control to design a novel control method based on data, which can decrease the computational time and difficulty of a nonlinear system. Simulations on MATLAB prove the efficiency of the given method. The simulation results validate that the designed controller has improved position control than the traditional proportional integral derivative, model-free-adaptive control, and model-free-learning-adaptive control.


Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 154
Author(s):  
Bin Wang ◽  
Pengda Ren ◽  
Xinhao Huang

A piston piezoelectric (PZT) pump has many advantages for the use of light actuators. How to deal with the contradiction between the intermittent oil supplying and position control precision is essential when designing the controller. In order to accurately control the output of the actuator, a backstepping sliding-mode control method based on the Lyapunov function is introduced, and the controller is designed on the basis of establishing the mathematical model of the system. The simulation results show that, compared with fuzzy PID and ordinary sliding-mode control, backstepping sliding-mode control has a stronger anti-jamming ability and tracking performance, and improves the control accuracy and stability of the piezoelectric pump-controlled actuator system.


Author(s):  
Na Dong ◽  
Wenjin Lv ◽  
Shuo Zhu ◽  
Donghui Li

Model-free adaptive control has been developed greatly since it was proposed. Up to now, model-free adaptive control theory has become mature and tends to be an effective solution for complex unmodeled industrial systems. In practical industrial processes, most control systems are inevitably accompanied by noise that will result in indelible error and may further cause inaccurate feedback to the output. In order to solve this kind of problem with model-free technique, this article incorporates an improved tracking differentiator into model-free adaptive control. After that, the anti-noise model-free adaptive control method with complete convergence analysis is proposed. Meanwhile, numerical simulation proves that the improved control method can quickly track a given signal with good resistance to noise interference. Finally, the effectiveness and practicability of the proposed algorithm are verified by experiments through the control of drum water level of circulating fluidized.


Author(s):  
Chung Hwan Kim ◽  
Ha-Il You ◽  
Seung-Hyun Lee

The manufacture of printed electronics by roll-to-roll printing machine requires more accurate register performance than conventional media printing technology. Moreover, high drying temperature and long drying time to sinter the inks can induce the substantial changes in the length of the substrate and consequently register errors. Among the roll-to-roll printing methods, the gravure one, despite its relatively fast productivity and fine-line printing capacity, has difficulty in achieving the required register specifications for printed electronics because of the dependence of the register control on web dynamics. This study proposes a roll-to-roll gravure-offset printing equipment, including the register measurement system designed to enhance register performance and the related register control method for the application of printed electronics. Each cylinder constituting the printing unit is driven independently by an individual servomotor. Moreover, the printing patterns of the plate cylinder can move in the axial direction by position control, as well as in the web transport direction by a phase shift of the plate cylinder, without affecting the dynamics of the web. The time difference between the measurement and the actual control action is considered and modeled. The register measurement system, including selections of sensors and marks is also proposed to consider the effect of the time difference. The simulation results and the experiments of the register control are shown to verify the effect of the time difference on the control performances. It is found that a proper estimation of time difference should be obtained in order to guarantee more accurate and stable control performances.


2012 ◽  
Vol 220-223 ◽  
pp. 1012-1017
Author(s):  
Qing Guo ◽  
Dan Jiang

This paper has introduced electromechanical coupling characteristics in the lower extremity exoskeleton systems, considered model ,according to legs supporting gait when people walking, established the load torque compensation model , and a mathematical model of knee position control system which is made of the servo valve, hydraulic cylinders and other hydraulic components, designed hydraulic cylinder position control loop in case of existing load force interference compensation, and used the method of combining the PID and lead correction network for frequency domain design ,ensured system to meet a certain stability margin. The simulation results show that this position control method can servo on the knee angular displacement of normal human walking, reached a certain exoskeleton boost effect, at the same time, met the needs of human-machine coordinated motion.


2021 ◽  
pp. 107754632110340
Author(s):  
Jia Wu ◽  
Ning Liu ◽  
Wenyan Tang

This study investigates the tracking consensus problem for a class of unknown nonlinear multi-agent systems A novel data-driven protocol for this problem is proposed by using the model-free adaptive control method To obtain faster convergence speed, one-step-ahead desired signal is introduced to construct the novel protocol Here, switching communication topology is considered, which is not required to be strongly connected all the time Through rigorous analysis, sufficient conditions are given to guarantee that the tracking errors of all agents are convergent under the novel protocol Examples are given to validate the effectiveness of results derived in this article


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