Design and Control of a Hydraulic Human Power Amplifier

2004 ◽  
Author(s):  
Perry Y. Li
Keyword(s):  
Power Amplifier ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parametric Uncertainties ◽  
Hydraulic Actuator ◽  
Closed Loop System ◽  
Static Loads ◽  
Human Power ◽  
Compression Spring ◽  
And Control

This paper describes the design of and some preliminary control results for a hydraulically actuated human power amplifier. The system is in the form of an oar, with its reach and pitch degrees of freedom being hydraulically assisted. A robust PI force controller is proposed so that the hydraulic actuator force tracks a scaled copy of the force exerted by the human. Nonlinearities and uncertainties in the compression spring, as well as parametric uncertainties are taken into account. The passivity property of the closed loop system is also analyzed. The controller has been tested in simulations and experimentally. It is shown to be effective when pushing against an object, and in assisting in bearing static loads.

Design and Stability Analysis of a QFT Pressure Controller of a Hydraulic Actuator Using Takagi-Sugeno Fuzzy Model

2015 ◽  
Author(s):  
Masoumeh Esfandiari ◽  
Nariman Sepehri
Keyword(s):  
Stability Analysis ◽  
Closed Loop ◽  
Nonlinear Function ◽  
Loop System ◽  
Performance Criteria ◽  
Parametric Uncertainties ◽  
Hydraulic Actuator ◽  
Closed Loop System ◽  
Takagi Sugeno ◽  
Operating Points

In this paper, a robust, fixed-gain, and linear controller is designed for the output pressure of an electro-hydraulic actuator with parametric uncertainties. Quantitative feedback theory (QFT) is selected as the design technique. The objective is to satisfy specified performance criteria in terms of tracking, stability, and disturbance rejection. To design the QFT controller, the required family of frequency responses is obtained by linearizing the hydraulic nonlinear function around operating points of interest, and constructing an equivalent linear plant set. As a result, the stability of the closed-loop system is guaranteed only around the limited number of operating points, and specified values for system parameters. To overcome this limitation, Takagi-Sugeno (T-S) fuzzy modeling is employed. This way the nonlinear stability of the closed-loop system is investigated and ensured for a continuous range of parametric uncertainties and region of operating points. Having successful results from stability analysis, the QFT controller is applied on the experimental set-up. The experimental results are in accordance with the specified criteria.

scholarly journals Design, Construction, and Control for an Underwater Vehicle Type Sepiida

Robotica ◽  
2020 ◽  
pp. 1-18
Author(s):  
M. Garcia ◽  
P. Castillo ◽  
E. Campos ◽  
R. Lozano
Keyword(s):  
Embedded System ◽  
Closed Loop ◽  
Underwater Vehicle ◽  
Mathematical Representation ◽  
Closed Loop System ◽  
Vehicle Type ◽  
Mathematical Equations ◽  
And Control ◽  
Design Construction

SUMMARY A novel underwater vehicle configuration with an operating principle as the Sepiida animal is presented and developed in this paper. The mathematical equations describing the movements of the vehicle are obtained using the Newton–Euler approach. An analysis of the dynamic model is done for control purposes. A prototype and its embedded system are developed for validating analytically and experimentally the proposed mathematical representation. A real-time characterization of one mass is done to relate the pitch angle with the radio of displacement of the mass. In addition, first validation of the closed-loop system is done using a linear controller.

scholarly journals Robust and Optimal Output-Feedback Control for Interval State-Space Model: Application to a Two-Degrees-of-Freedom Piezoelectric Tube Actuator

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Mounir Hammouche ◽  
Philippe Lutz ◽  
Micky Rakotondrabe
Keyword(s):  
State Space ◽  
Output Feedback ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
State Space Model ◽  
Output Feedback Control ◽  
Optimal Solution ◽  
Loop System ◽  
Closed Loop System ◽  
Optimal Output

The problem of robust and optimal output feedback design for interval state-space systems is addressed in this paper. Indeed, an algorithm based on set inversion via interval analysis (SIVIA) combined with interval eigenvalues computation and eigenvalues clustering techniques is proposed to seek for a set of robust gains. This recursive SIVIA-based algorithm allows to approximate with subpaving the set solutions [K] that satisfy the inclusion of the eigenvalues of the closed-loop system in a desired region in the complex plane. Moreover, the LQ tracker design is employed to find from the set solutions [K] the optimal solution that minimizes the inputs/outputs energy and ensures the best behaviors of the closed-loop system. Finally, the effectiveness of the algorithm is illustrated by a real experimentation on a piezoelectric tube actuator.

Dynamic Modeling and Control of Packing Pressure in Injection Molding

1994 ◽  
Vol 116 (2) ◽  
pp. 244-249 ◽  
Author(s):  
J. Hu ◽  
J. H. Vogel
Keyword(s):  
Injection Molding ◽  
Closed Loop ◽  
Good Control ◽  
Pressure Control ◽  
Physical Parameters ◽  
Closed Loop System ◽  
Modeling And Control ◽  
Packing Pressure ◽  
And Control ◽  
Plastic Injection

A dynamic model of injection molding developed from physical considerations is used to select PID gains for pressure control during the packing phase of thermo-plastic injection molding. The relative importance of various aspects of the model and values for particular physical parameters were identified experimentally. The controller gains were chosen by pole-zero cancellation and root-locus methods, resulting in good control performance. Both open and closed-loop system responses were predicted and verified, with good overall agreement.

Singularity analysis of a 7-DOF spatial hybrid manipulator for medical surgery

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sameer Gupta ◽  
Ekta Singla ◽  
Sanjeev Soni ◽  
Ashish Singla
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Singularity Analysis ◽  
Medical Surgery ◽  
Natural Motion ◽  
Hybrid Manipulator ◽  
Contour Plots ◽  
Kinematic Singularities ◽  
And Control ◽  
Optimal Configurations

Abstract This paper presents the singularity analysis of a 7-degrees of freedom (DOF) hybrid manipulator consisting of a closed-loop within it. From the past studies, it is well-known that the kinematic singularities play a significant role in the design and control of robotic manipulators. Kinematic singularities pose two-fold effects – first, they can induce the loss of one or more DOF of the manipulator and cause infinite joint rates at that particular joint, and second, they help to determine the trajectory or zone with high mechanical advantage. In current work, a 7-DOF hybrid manipulator is considered which is being developed at Council Of Scientific And Industrial Research–Central Scientific Instruments Organisation (CSIR–CSIO) Chandigarh to assist a surgeon during a medical-surgical task. To emulate the natural motion of a surgeon, the challenging configuration with redundant DOF is utilized. Jacobian has been computed analytically and analyzed at each instantaneous configuration with the evaluation of manipulability. Effect of a closed loop in the hybrid configurations is focused at, and utilizing the contour plots, good and worst working zones are identified in the workspace of the manipulator. The verification and validation of best and worst manipulability points (singularities) are done with the help of genetic algorithms, to determine locally and globally optimal configurations. Finally, on the basis of the singularity analysis, the present work concludes with few guidelines to the surgeon about the best and worst working zones for surgical tasks.

Design of Output Feedback Controller for Switched Fuzzy Systems with Time-Delay

2014 ◽  
Vol 635-637 ◽  
pp. 1443-1446
Author(s):  
Hong Yang ◽  
Huan Huan Lü ◽  
Le Zhang
Keyword(s):  
Time Delay ◽  
Output Feedback ◽  
Fuzzy Systems ◽  
Closed Loop ◽  
Feedback Controller ◽  
Linear Matrix ◽  
Sufficient Condition ◽  
Closed Loop System ◽  
Output Feedback Controller ◽  
And Control

This paper investigates the problems of stabilization and control for time-delay switched fuzzy systems using output feedback controller. Based on the linear matrix inequality (LMI) technique, multiple Lyapunov method is used to obtain a sufficient condition for the existence of the controller for the output feedback. Then an algorithm is constructed to transform the sufficient condition into a LMI form, thus obtaining a method for designing the controller. The designed controller guarantees the closed-loop system to be asympototically stable. A numerical example is given to show the effectiveness of our method.

Feedback Control of Linear Distributed Systems

1967 ◽  
Vol 89 (2) ◽  
pp. 379-383 ◽  
Author(s):  
Donald M. Wiberg
Keyword(s):  
Boundary Condition ◽  
Distributed Systems ◽  
Feedback Control ◽  
Closed Loop ◽  
The State ◽  
Loop System ◽  
Closed Loop System ◽  
Loop Equation ◽  
Control Feedback ◽  
And Control

The optimum feedback control of controllable linear distributed stationary systems is discussed. A linear closed-loop system is assured by restricting the criterion to be the integral of quadratics in the state and control. Feedback is obtained by expansion of the linear closed-loop equation in terms of uncoupled modes. By incorporating symbolic functions into the formulation, one can treat boundary condition control and point observable systems that are null-delta controllable.

Multi-Objective Robust Decentralized Control for the Interconnected Fuzzy Singularly Perturbed Models

2012 ◽  
Vol 182-183 ◽  
pp. 1200-1205
Author(s):  
Ye Nan Hu ◽  
Fu Chun Sun
Keyword(s):  
Decentralized Control ◽  
Closed Loop ◽  
Control Method ◽  
Dynamic Performance ◽  
Singularly Perturbed ◽  
Disturbance Attenuation ◽  
Closed Loop System ◽  
Multi Objective ◽  
Robust Decentralized Control ◽  
And Control

A multi-objective robust decentralized control method is proposed for the interconnected fuzzy singularly perturbed models. Such decentralized controller can guarantee the whole closed-loop system is asymptotically stable even when the multi-time-scale subsystems are interactional. Besides, the disturbance attenuation performance, dynamic performance and control amplitude can be optimized synthetically. The simulations illustrate the effectiveness of the proposed method.

Multi Degree-of-Freedom Hydraulic Human Power Amplifier With Rendering of Assistive Dynamics

2016 ◽  
Author(s):  
Sangyoon Lee ◽  
Fredrik Eskilsson ◽  
Perry Y. Li
Keyword(s):  
Power Amplifier ◽  
Degree Of Freedom ◽  
Hydraulic Actuator ◽  
Full Account ◽  
Control Approach ◽  
Human Power ◽  
Natural Energy ◽  
Control Objective ◽  
Pressure Dynamics ◽  
Mechanical Tool

The hydraulic human power amplifier (HPA) is a tool similar to exoskeleton that uses hydraulic actuation to amplify the applied human force. The control objective is to make the system behave like a passive mechanical tool that interacts with the human and the environment passively with a specified power scaling factor. In our previous work, a virtual velocity coordination approach recasts the single degree-of-freedom human power amplifier control problem into a velocity coordination with a fictitious reference mechanical system. Force amplification becomes a natural consequence of the velocity coordination. In this paper, this control approach is extended for fully coupled multi-DoF systems. A passivity based control approach that uses the natural energy storage of the hydraulic actuator to take full account of the nonlinear pressure dynamics is used to define the flow requirement. Additional passive assistance dynamics are designed and implemented to enable the user to perform specific tasks more easily. Guidance is achieved using a passive velocity field controller (PVFC), and obstacle avoidance is achieved using a potential field. Experimental results demonstrate good performance on a 2-DoF Human Power Amplifier.

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