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.

Passive Control of a Hydraulic Human Power Amplifier Using a Hydraulic Transformer

2015 ◽  
Author(s):  
Sangyoon Lee ◽  
Perry Y. Li
Keyword(s):  
Power Amplifier ◽  
Passive Control ◽  
Control Function ◽  
Hydraulic Actuator ◽  
Control Approach ◽  
Human Power ◽  
Hydraulic Transformer ◽  
Control Objective ◽  
Pressure Dynamics ◽  
Mechanical Tool

The hydraulic human power amplifier is a tool that uses hydraulic actuation to amplify the force that the human exerts on it. Our control objective and framework are to make the system behave like a passive mechanical tool when interacting with the human and with the work environment with a specified power scaling factor. A virtual velocity coordination control approach casts the human power amplifier problem into one of velocity coordination by generating a fictitious reference mechanical system. Force amplification becomes a natural consequence of velocity coordination. This control has been previously demonstrated using servo valves which is a major contributor to energy loss in hydraulic system. In this paper, a hydraulic transformer, which does not rely on throttling to accomplish its control function is used instead of a servo valve to achieve human power amplification. In addition, a passivity based control approach that makes use of the natural energy storage of the hydraulic actuator is used to define the flow requirement. This approach fully accounts for the non-linearity due to the pressure dynamics. The controller was experimentally validated with good force amplification and velocity coordination performance on a single degree of freedom hydraulic human power amplifier.

A New Passive Controller for a Hydraulic Human Power Amplifier

2006 ◽  
Author(s):  
Perry Y. Li
Keyword(s):  
Work Environment ◽  
Mechanical System ◽  
Power Amplifier ◽  
Scaling Factor ◽  
Natural Consequence ◽  
Constrained Motion ◽  
Proportional Integral ◽  
Human Power ◽  
Control Objective ◽  
Mechanical Tool

A new, intrinsically passive controller for hydraulic human power amplifier is presented. The hydraulic human power amplifier is a tool that amplifies (or attenuates) the force that the human exerts on it. The control objective is to cause the system to behave like a passive mechanical tool when interacting with the human and with the work environment with a specified power scaling factor. Although a previous Proportional-integral with velocity feedforward force controller [1] works well in the constrained space, it lacks robustness or performance during freemotion because of the sensitivity to the implementation of velocity feedforward term. The difficulty in implementing the velocity feedforward term also prevents the controller from being intrinsically passive. The new controller recasts the human power amplifier problem into one of velocity coordination by generating a fictitious reference mechanical system. Force amplification become a natural consequence of velocity coordination. This enables the controller to be intrinsically passive and to achieve good performance both in free motion and constrained motion. These properties have been experimentally validated.

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

2020 ◽  
Vol 28 (4) ◽  
pp. 1296-1308
Author(s):  
Sangyoon Lee ◽  
Perry Y. Li ◽  
Fredrik Eskilsson
Keyword(s):  
Power Amplifier ◽  
Degree Of Freedom ◽  
Human Power

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.

scholarly journals The Human Power Amplifier Technology at the University Of California, Berkeley

1996 ◽  
Vol 29 (1) ◽  
pp. 5715-5720
Author(s):  
H. Kazerooni ◽  
Tanya J. Snyder
Keyword(s):  
Power Amplifier ◽  
University Of California ◽  
Human Power ◽  
The University

Adaptive Control of a Sliding Seat Using Magnetorheological Energy Absorbers

2010 ◽  
Author(s):  
Min Mao ◽  
Norman M. Wereley ◽  
Alan L. Browne
Keyword(s):  
Adaptive Control ◽  
Degrees Of Freedom ◽  
Adaptive Controller ◽  
Degree Of Freedom ◽  
Lumped Mass ◽  
Adaptive Controllers ◽  
Bingham Number ◽  
Control Objective ◽  
Payload Mass ◽  
Energy Absorbers

Feasibility of a sliding seat utilizing adaptive control of a magnetorheological (MR) energy absorber (MREA) to minimize loads imparted to a payload mass in a ground vehicle for frontal impact speeds as high as 7 m/s (15.7 mph) is investigated. The crash pulse for a given impact speed was assumed to be a rectangular deceleration pulse having a prescribed magnitude and duration. The adaptive control objective is to bring the payload (occupant plus seat) mass to a stop using the available stroke, while simultaneously accommodating changes in impact velocity and occupant mass ranging from a 5th percentile female to a 95th percentile male. The payload is first treated as a single-degree-of-freedom (SDOF) rigid lumped mass, and two adaptive control algorithms are developed: (1) constant Bingham number control, and (2) constant force control. To explore the effects of occupant compliance on adaptive controller performance, a multi-degree-of-freedom (MDOF) lumped mass biodynamic occupant model was integrated with the seat mass. The same controllers were used for both the SDOF and MDOF cases based on SDOF controller analysis because the biodynamic degrees of freedom are neither controllable nor observable. The designed adaptive controllers successfully controlled load-stroke profiles to bring payload mass to rest in the available stroke and reduced payload decelerations. Analysis showed extensive coupling between the seat structures and occupant biodynamic response, although minor adjustments to the control gains enabled full use of the available stroke.

Design and Control of a Compact and Flexible Pneumatic Artificial Muscle Actuation System: Part Two—Robust Control

2011 ◽  
Author(s):  
Sai-Kit Wu ◽  
Garrett Waycaster ◽  
Tad Driver ◽  
Xiangrong Shen
Keyword(s):  
Robust Control ◽  
Nonlinear Model ◽  
Sliding Mode ◽  
Artificial Muscle ◽  
Control Approach ◽  
Actuation System ◽  
Highly Nonlinear ◽  
Pressure Dynamics ◽  
System Part ◽  
And Control

A robust control approach is presented in this part of the paper, which provides an effective servo control for the novel PAM actuation system presented in Part I. Control of PAM actuation systems is generally considered as a challenging topic, due primarily to the highly nonlinear nature of such system. With the introduction of new design features (variable-radius pulley and spring-return mechanism), the new PAM actuation system involves additional nonlinearities (e.g. the nonlinear relationship between the joint angle and the actuator length), which further increasing the control difficulty. To address this issue, a nonlinear model based approach is developed. The foundation of this approach is a dynamic model of the new actuation system, which covers the major nonlinear processes in the system, including the load dynamics, force generation from internal pressure, pressure dynamics, and mass flow regulation with servo valve. Based on this nonlinear model, a sliding mode control approach is developed, which provides a robust control of the joint motion in the presence of model uncertainties and disturbances. This control was implemented on an experimental setup, and the effectiveness of the controller demonstrated by sinusoidal tracking at different frequencies.

scholarly journals Robust Control Design to the Furuta System under Time Delay Measurement Feedback and Exogenous-Based Perturbation

Mathematics ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 2131
Author(s):  
Gisela Pujol-Vazquez ◽  
Saleh Mobayen ◽  
Leonardo Acho
Keyword(s):  
Time Delay ◽  
Output Feedback Control ◽  
Linear Matrix ◽  
Control Block ◽  
Control Approach ◽  
Delay Measurement ◽  
Control Objective ◽  
Measurement Feedback ◽  
Robust Control Design ◽  
Delay Dependent

When dealing with real control experimentation, the designer has to take into account several uncertainties, such as: time variation of the system parameters, exogenous perturbation and the presence of time delay in the feedback line. In the later case, this time delay behaviour may be random, or chaotic. Hence, the control block has to be robust. In this work, a robust delay-dependent controller based on H∞ theory is presented by employing the linear matrix inequalities techniques to design an efficient output feedback control. This approach is carefully tuned to face with random time-varying measurement feedback and applied to the Furuta pendulum subject to an exogenous ground perturbation. Therefore, a recent experimental platform is described. Here, the ground perturbation is realised using an Hexapod robotic system. According to experimental data, the proposed control approach is robust and the control objective is completely satisfied.

Control Method for Vehicles on Base of Natural Energy Recovery

2014 ◽  
Vol 670-671 ◽  
pp. 1330-1336 ◽  
Author(s):  
Viacheslav Pshikhopov ◽  
Mikhail Medvedev ◽  
Anatoly Gaiduk
Keyword(s):  
Energy Recovery ◽  
Control Method ◽  
Minimum Energy ◽  
Electrical Power ◽  
Movement Control ◽  
Wheel Slip ◽  
Control Approach ◽  
Minimum Energy Consumption ◽  
Natural Energy ◽  
Vehicle Velocity

This paper is devoted to vehicle movement control method based on the natural energy recovery [1] and position-path control approach [2,3,4]. This method ensures the fullest use of kinematic energy of the controlled vehicle. Method is applied for path profile with variable height. Vehicle velocity is changed to minimize kinematic energy losses. The time of the path passage is accounted in the designed method. In this report typical profiles of the controlled vehicle are considered. In general case the vehicle velocity program is developed on base of solutions for typical profiles. The vehicle velocity program is changing while vehicle is moving. The developed method is applied for control of trains implemented with electrical power drives. On base of train model studying it is proved that optimal mode of trains acceleration is maximal traction. The maximal traction ensures minimum energy consumption of train drives. But the traction of trains is extreme function of the speed wheel slip [5, 6]. Therefore the new extreme control for the train drives is developed. This method supports trains traction in extreme value. The developed method is implemented in simulator based on Matlab and Universal Mechanism. Movement of a freight train on a real track section is simulated.

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