Motion Control of an Omni-Directional Walker for Walking Support

2013 ◽  
pp. 20-28
Author(s):  
Renpeng Tan ◽  
Shuoyu Wang ◽  
Yinlai Jiang ◽  
Kenji Ishida ◽  
Masakatsu G. Fujie
Keyword(s):  
Adaptive Control ◽  
Motion Control ◽  
Control Method ◽  
Center Of Gravity ◽  
Path Tracking ◽  
Reference Trajectory ◽  
Tracking Errors ◽  
Directed Movement ◽  
Load Change

With the increase in the percentage of the population defined as elderly, increasing numbers of people suffer from walking disabilities due to illness or accidents. An omni-directional walker (ODW) has been developed that can support people with walking disabilities and allow them to perform indoor walking. The ODW can identify the user’s directional intention based on the user’s forearm pressures and then supports movement in the intended direction. In this chapter, a reference trajectory is generated based on the intended direction in order to support directed movement. The ODW needs to follow the generated path. However, path tracking errors occur because the center of gravity (COG) of the system shifts and the load changes due to user`s pressure. An adaptive control method is proposed to deal with this issue. The results of simulations indicate that the ODW can accurately follow the user’s intended direction by inhibiting the influence of COG shifts and the resulting load change. The proposed scheme is feasible for supporting indoor movement.

Motion Control of an Omni-Directional Walker for Walking Support

2013 ◽  
pp. 614-622
Author(s):  
Renpeng Tan ◽  
Shuoyu Wang ◽  
Yinlai Jiang ◽  
Kenji Ishida ◽  
Masakatsu G. Fujie
Keyword(s):  
Adaptive Control ◽  
Motion Control ◽  
Control Method ◽  
Center Of Gravity ◽  
Path Tracking ◽  
Reference Trajectory ◽  
Tracking Errors ◽  
Directed Movement ◽  
Load Change

With the increase in the percentage of the population defined as elderly, increasing numbers of people suffer from walking disabilities due to illness or accidents. An omni-directional walker (ODW) has been developed that can support people with walking disabilities and allow them to perform indoor walking. The ODW can identify the user's directional intention based on the user's forearm pressures and then supports movement in the intended direction. In this chapter, a reference trajectory is generated based on the intended direction in order to support directed movement. The ODW needs to follow the generated path. However, path tracking errors occur because the center of gravity (COG) of the system shifts and the load changes due to user`s pressure. An adaptive control method is proposed to deal with this issue. The results of simulations indicate that the ODW can accurately follow the user's intended direction by inhibiting the influence of COG shifts and the resulting load change. The proposed scheme is feasible for supporting indoor movement.

scholarly journals Disturbance compensation-based output feedback adaptive control for shape memory alloy actuator system

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142199399
Author(s):  
Xiaoguang Li ◽  
Bi Zhang ◽  
Daohui Zhang ◽  
Xingang Zhao ◽  
Jianda Han
Keyword(s):  
Adaptive Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Method ◽  
Control Law ◽  
Reference Trajectory ◽  
Disturbance Compensation ◽  
Comparison Results ◽  
Control Scheme ◽  
Actuator System

Shape memory alloy (SMA) has been utilized as the material of smart actuators due to the miniaturization and lightweight. However, the nonlinearity and hysteresis of SMA material seriously affect the precise control. In this article, a novel disturbance compensation-based adaptive control scheme is developed to improve the control performance of SMA actuator system. Firstly, the nominal model is constructed based on the physical process. Next, an estimator is developed to online update not only the unmeasured system states but also the total disturbance. Then, the novel adaptive controller, which is composed of the nominal control law and the compensation control law, is designed. Finally, the proposed scheme is evaluated in the SMA experimental setup. The comparison results have demonstrated that the proposed control method can track reference trajectory accurately, reject load variations and stochastic disturbances timely, and exhibit satisfactory robust stability. The proposed control scheme is system independent and has some potential in other types of SMA-actuated systems.

scholarly journals Motion Control of a Cushion Robot Considering Load Change and Center of Gravity Shift

2012 ◽  
Vol 6 (5) ◽  
pp. 740-753 ◽  
Author(s):  
Renpeng TAN ◽  
Shuoyu WANG ◽  
Yinlai JIANG
Keyword(s):  
Motion Control ◽  
Center Of Gravity ◽  
Load Change

scholarly journals Research on a Nonlinear Robust Adaptive Control Method of the Elbow Joint of a Seven-Function Hydraulic Manipulator Based on Double-Screw-Pair Transmission

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Gaosheng Luo ◽  
Jiawang Chen ◽  
Linyi Gu
Keyword(s):  
Adaptive Control ◽  
Elbow Joint ◽  
Control Method ◽  
Dynamic Performance ◽  
Robust Adaptive Control ◽  
Reference Trajectory ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Hydraulic Manipulator ◽  
Robust Adaptive

A robust adaptive control method with full-state feedback is proposed based on the fact that the elbow joint of a seven-function hydraulic manipulator with double-screw-pair transmission features the following control characteristics: a strongly nonlinear hydraulic system, parameter uncertainties susceptible to temperature and pressure changes of the external environment, and unknown outer disturbances. Combined with the design method of the back-stepping controller, the asymptotic stability of the control system in the presence of disturbances from uncertain systematic parameters and unknown external disturbances was demonstrated using Lyapunov stability theory. Based on the elbow joint of the seven-function master-slave hydraulic manipulator for the 4500 m Deep-Sea Working System as the research subject, a comparative study was conducted using the control method presented in this paper for unknown external disturbances. Simulations and experiments of different unknown outer disturbances showed that (1) the proposed controller could robustly track the desired reference trajectory with satisfactory dynamic performance and steady accuracy and that (2) the modified parameter adaptive laws could also guarantee that the estimated parameters are bounded.

Adaptive attitude controller design for tail-sitter unmanned aerial vehicles

2020 ◽  
pp. 107754632092535
Author(s):  
Deyuan Liu ◽  
Hao Liu ◽  
Jiansong Zhang ◽  
Frank L Lewis
Keyword(s):  
Adaptive Control ◽  
Unmanned Aerial Vehicles ◽  
Control Method ◽  
Controller Design ◽  
Dynamic Pressure ◽  
Tracking Errors ◽  
Control Approach ◽  
Aerial Vehicles ◽  
Attitude Tracking ◽  
Mode Transitions

Tail-sitter unmanned aerial vehicles have two flight modes: they can fly long distances at high cruising speeds as fixed-wing aircrafts; or hover, take off, and land vertically as rotary-wing aircrafts. The tail-sitter dynamics involves serious nonlinearities and high uncertainties, especially in the two flight mode transitions. In this article, an adaptive control approach is proposed for a class of tail-sitter unmanned aerial vehicles to achieve the robustness properties. The control torque allocation problem is addressed based on the dynamic pressure in the transition flight. The proposed control method does not need to switch the coordinate system, the controller structure, or the controller parameters in different flight modes. It is proven that the attitude tracking errors can converge into a given neighborhood of the origin in finite time. Simulation results are presented to show the advantages of the proposed adaptive control method.

Modified Model-Free Adaptive Control Method Applied to Vibration Control of an Elastic Crane

2019 ◽  
Author(s):  
Hoang Anh Pham ◽  
Dirk Söffker
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Structural Information ◽  
Control Strategies ◽  
Control Input ◽  
Tracking Errors ◽  
Adaptive Controllers ◽  
Control Approach ◽  
Model Free ◽  
Controlled Systems

Abstract Model-free adaptive control (MFAC) is a data-driven control approach receiving increased attention in the last years. Different model-free-based control strategies are proposed to design adaptive controllers when mathematical models of the controlled systems should not be used or are not available. Using only measurements (I/O data) from the system, a feedback controller is generated without the need of any structural information about the controlled plant. In this contribution an improved MFAC is discussed for control of unknown multivariable flexible systems. The main improvement in control input calculation is based on the consideration of output tracking errors and its variations. A new updated control input algorithm is developed. The novel idea is firstly applied for controlling vibrations of a MIMO ship-mounted crane. The control efficiency is verified via numerical simulations. The simulation results demonstrate that vibrations of the elastic boom and the payload of the crane can be reduced significantly and better control performance is obtained when using the proposed controller compared to standard model-free adaptive and PI controllers.

Sign in / Sign up

Export Citation Format

Share Document