Hopping robot - Stance

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Continuous stirred-tank reactor system

Model description: 

The following CSTR system developed by Liu(1967). The reaction is exothermic first-order, $A \rightarrow B$, and is given by the following mass and energy balances. One should notice that the energy balance includes cooling water jacket dynamics. The following model was identified using regression techniques on the energy balance equations:

$$\begin{align*} y(k) &= 1.3187y(k-1) - 0.2214y(k-2) - 0.1474y(k-3) \\ &- 8.6337u(k-1) + 2.9234u(k-2) + 1.2493u(k-3) \\ &- 0.0858y(k-1)u(k-1) + 0.0050y(k-2)u(k-1) \\ &+ 0.0602y(k-2)u(k-2) + 0.0035y(k-3)u(k-1) \\ &- 0.0281y(k-3)u(k-2) + 0.0107y(k-3)u(k-3). \end{align*}$$

Type: 

Form: 

Model order: 

3

Time domain: 

Linearity: 

Autonomity: 

Publication details: 

TitleIdentification and Control of Bilinear Systems
Publication TypeConference Paper
Year of Publication1992
AuthorsBartee, James F., and Georgakis Christos
Conference NameAmerican Control Conference, 1992
Date Published06/1992
PublisherIEEE
Conference LocationChicago, Illinois
ISBN Number0-7803-0210-9
KeywordsAlgorithm design and analysis, Chemical processes, Continuous-stirred tank reactor, control system synthesis, Control systems, Control theory, linear systems, nonlinear control systems, nonlinear systems, process control
AbstractThe research presented in this paper combines the problem of identifiction and control of nonlinear processes. This is done by approximating the process with a bilinear model and designing model-based control structures (Reference System Controllers) based on the bilinear approximation. The identification of the bilinear model and the construction of the controller are described below. An example of the identification and control of an exothermic CSTR is also presented.
URLhttp://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=4792606&queryText%3DIdentification+and+Control+of+Bilinear+Systems

Pendulum system with Coulomb friction

Model description: 

Consider a pendulum system with Coulomb friction and external perturbation

$$ \ddot {\theta} = \frac{1}{J}u - \frac{g}{L}\sin \theta - \frac{V_s}{J}\dot{\theta } - \frac{P_s}{J}\mathrm{sgn}(\dot{\theta}) + \upsilon, $$

where parameters have the following values $M=1.1$, $L=0.9$, $J=ML^2=0.891$, $V_s=0.18$, $P_s=0.18$, $P_s=0.45$, $g=9.815$, and $v$ is an uncertain external perturbation $|\upsilon| \leq 1$.

Type: 

Form: 

Model order: 

2

Time domain: 

Linearity: 

Publication details: 

TitleA Simple Nonlinear Observer for a Class of Uncertain Mechanical Systems
Publication TypeJournal Article
Year of Publication2007
AuthorsSu, Yuxin, Müller P.C., and Zheng Chunhong
JournalIEEE Transactions on Automatic Control
Volume52
Start Page1340
Issue7
Pagination1340-1345
Date Published07/2007
ISSN0018-9286
Accession Number9606706
Keywordsasymptotic stability, MIMO systems, nonlinear control systems, observers, uncertain systems
AbstractA simple nonlinear observer is proposed for a class of uncertain nonlinear multiple-input-multiple-output (MIMO) mechanical systems whose dynamics are first-order differentiable. The global asymptotic observation of the proposed observer is proved. Thus, the observer can be designed independently of the controller. Furthermore, the proposed observer is formulated without any detailed model knowledge of the system. These advantages make it easy to implement. Numerical simulations are included to illustrate the effectiveness of the proposed observer.
DOI10.1109/TAC.2007.900851

Generic nonlinear system 2

Model description: 

$$\begin{align*} x_1(k+1) &= 0.9x_1(k)\sin{[x_2(k)]} + \left(2 + 1.5 \dfrac{x_1(k)u_1(k)}{1+x_1^2(k)u_1^2(k)}\right)u_1(k) + \left(x_1(k) + \dfrac{2x_1(k)}{1+x_1^2(k)}\right)u_1(k)\\ x_2(k+1) &= x_3(k)(1+\sin{[4x_3(k)]}+ \dfrac{x_3(k)}{1+x_3^2(k)}\\ x_3(k+1) &= (3 + \sin{[2x_1(k)]})u_2(k)\\ y_1(k)&=x_1(k)\\ y_2(k)&=x_2(k) \end{align*}$$

Type: 

Form: 

Model order: 

3

Time domain: 

Linearity: 

Publication details: 

TitleAdaptive control of nonlinear multivariable systems using neural networks
Publication TypeConference Paper
Year of Publication1993
AuthorsNarendra, K.S., and Mukhopadhyay S.
Conference NameProceedings of the 32nd IEEE Conference on Decision and Control, 1993.
Date Published12/1993
PublisherIEEE
Conference LocationSan Antonio, TX
ISBN Number0-7803-1298-8
Accession Number4772091
Keywordsadaptive control, multivariable systems, neural nets, nonlinear systems
AbstractIn this paper we examine the problem of control of multivariable systems using neural networks. The problem is discussed assuming different amounts of prior information concerning the plant and hence different levels of complexity. In the first stage it is assumed that the state equations describing the plant are known and that the state of the system is accessible. Following this the same problem is considered when the state equations are unknown. In the last stage the adaptive control of the multivariable system using only input-output data is discussed in detail. The objective of the paper is to demonstrate that results from nonlinear control theory and linear adaptive control theory can be used to design practically viable controllers for unknown nonlinear multivariable systems using neural networks. The different assumptions that have to be made, the choice of identifier and controller architectures and the generation of adaptive laws for the adjustment of the parameters of the neural networks form the core of the paper
DOI10.1109/CDC.1993.325299

Hopping robot - Flight

Model description: 

$$\dot{x}=A_Fx+b_F\tau+e_F(x)$$

with

$A_S = \begin{bmatrix} 0 & 1 & 0 & 0 \\ 0 & 0 & -K \dfrac{m_n}{\beta_F} & -C \dfrac{m_n}{\beta_F} \\ 0 & 0 & 0 & 1 \\ 0 & 0 & -K \dfrac{m_{bnt}}{\beta_F} & -C \dfrac{m_{bnt}}{\beta_F} \\ \end{bmatrix},\\ x = \begin{bmatrix} z\\ \dot{z}\\ p\\ \dot{p} \end{bmatrix}, b_F = \dfrac{\eta}{\beta_{F}r} \begin{bmatrix} 0\\ m_n\\ 0\\ m_{bn} \end{bmatrix},\\ e_F(x)=\dfrac{1}{\beta_F} \begin{bmatrix} 0\\ \alpha(m_{bnt}g + f_{fF} + m_n(m_ng - k(s_0 - l_0) - f_p))\\ 0\\ -m_nf_{fF} - m_{bnt}(k(s_0-l_0) + f_a)\\ \end{bmatrix}. $

$z$ Body Height
$p$ Actuator Length
$\tau$ Motor Torque
$\theta$ Motor angle, $\theta = p/r$
$s$ Spring Length
$m_b$ 9.5kg Upper Leg Mass
$m_n$ 0.25kg Ball Nut Mass
$m_t$ 0.5kg Toe Mass
$k$ 400 N/m Spring Constant
$F_p$ 5.0N Leg Dry Friction
$F_z$ 1.5N Planarized Dry Friction
$F_a$ 0N Ball Screw Dry Friction
$c$ 5.5Ns/m Spring Viscous Friction
$\hat{\tau}$ 1.78Nm Stall Torque
$\hat{\omega}$ 2800RPM Max Speed
$\eta$ 0.95 Ball Screw Efficiency
$s_0$ 0.608m Spring Rest Length
$l_0$ 0.595m Maximum Leg Length
$J$ 2.7$\times$10$^{-4}$kgm$^2$ Motor Inertia
$\alpha$ 0.34kgm $J/r^2+m_n$
$\mu$ 0.05 $m_t/m_{bnt}$

Type: 

Form: 

Model order: 

4

Time domain: 

Linearity: 

Attachment: 

Publication details: 

TitleDesign, modeling and control of a hopping robot
Publication TypeConference Paper
Year of Publication1993
AuthorsRad, H., Gregorio P., and Buehler M.
Conference NameProceedings of the 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems '93, IROS '93.
Date Published06/1993
PublisherIEEE
Conference LocationYokohama
ISBN Number0-7803-0823-9
Accession Number5050001
Keywordslegged locomotion
AbstractThe authors report progress towards model based, dynamically stable legged locomotion with energy efficient, electrically actuated robots. The present the mechanical design of a prismatic robot leg which is optimized for electrical actuation. A dynamical model of the robot and the actuator as well as the interaction with ground is derived and validated by demonstrating close correspondence between simulations and experiments. A new continuous, and exactly implementable open loop torque control algorithm is introduced which stabilizes a limit cycle of the underlying fourth order intermittent robot/actuator/environment dynamics
DOI10.1109/IROS.1993.583877

Hopping robot - Stance

Model description: 

$$\dot{x}=A_Sx+b_S\tau+e_S(x)$$

with

$A_S = \begin{bmatrix} 0 & 1 & 0 & 0 \\ -K\dfrac{J}{\beta_Sr^2} & -C\dfrac{J}{\beta_Sr^2} & K\dfrac{J}{\beta_Sr^2} & C\dfrac{J}{\beta_Sr^2} \\ 0 & 0 & 0 & 1 \\ K\dfrac{m_b}{\beta_s} & C\dfrac{m_b}{\beta_s} & -K\dfrac{m_b}{\beta_s} & -C\dfrac{m_b}{\beta_s} \\ \end{bmatrix},\\ x = \begin{bmatrix} z\\ \dot{z}\\ p\\ \dot{p} \end{bmatrix}, b_S = \dfrac{\eta}{\beta_{S}r} \begin{bmatrix} 0\\ m_n\\ 0\\ m_{bn} \end{bmatrix},\\ e_S(x)=\dfrac{1}{\beta_s} \begin{bmatrix} 0\\ \alpha(ks_0 - m_{bn}g- f_{fS} + m_n(m_ng - ks_0 - f_a)\\ 0\\ 0\\ \end{bmatrix}. $

$z$ Body Height
$p$ Actuator Length
$\tau$ Motor Torque
$\theta$ Motor angle, $\theta = p/r$
$s$ Spring Length
$m_b$ 9.5kg Upper Leg Mass
$m_n$ 0.25kg Ball Nut Mass
$m_t$ 0.5kg Toe Mass
$k$ 400 N/m Spring Constant
$F_p$ 5.0N Leg Dry Friction
$F_z$ 1.5N Planarized Dry Friction
$F_a$ 0N Ball Screw Dry Friction
$c$ 5.5Ns/m Spring Viscous Friction
$\hat{\tau}$ 1.78Nm Stall Torque
$\hat{\omega}$ 2800RPM Max Speed
$\eta$ 0.95 Ball Screw Efficiency
$s_0$ 0.608m Spring Rest Length
$l_0$ 0.595m Maximum Leg Length
$J$ 2.7$\times$10$^{-4}$kgm$^2$ Motor Inertia
$\alpha$ 0.34kgm $J/r^2+m_n$
$\mu$ 0.05 $m_t/m_{bnt}$

Type: 

Form: 

Model order: 

4

Time domain: 

Linearity: 

Attachment: 

Publication details: 

TitleDesign, modeling and control of a hopping robot
Publication TypeConference Paper
Year of Publication1993
AuthorsRad, H., Gregorio P., and Buehler M.
Conference NameProceedings of the 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems '93, IROS '93.
Date Published06/1993
PublisherIEEE
Conference LocationYokohama
ISBN Number0-7803-0823-9
Accession Number5050001
Keywordslegged locomotion
AbstractThe authors report progress towards model based, dynamically stable legged locomotion with energy efficient, electrically actuated robots. The present the mechanical design of a prismatic robot leg which is optimized for electrical actuation. A dynamical model of the robot and the actuator as well as the interaction with ground is derived and validated by demonstrating close correspondence between simulations and experiments. A new continuous, and exactly implementable open loop torque control algorithm is introduced which stabilizes a limit cycle of the underlying fourth order intermittent robot/actuator/environment dynamics
DOI10.1109/IROS.1993.583877

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