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[AMR] Notes on tasks, improved layouts
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@@ -10,7 +10,8 @@ $ \begin{bmatrix}
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}
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Workspace $W$: $\theta_1, \theta_2 \in [-\pi, \pi]$.
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Similar for $n$R sys (more angles, more lengths).
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For 2D move in 3D space, last dim is sum of angles (or equiv). \bi{Jacobian}: see \ref{sec:ms-lin}
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For 2D move in 3D space, last dim is sum of angles (or equiv).
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The Jacobian of this $nD$ position is typically computed ($nD$ pos is a vec).
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\bi{Jacobian}: see \ref{sec:ms-lin}.
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\shortdefinition[Singularity] Loss of deg of Freed. $\det(\mat{J}(\vec{\theta})) = 0$
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% TODO: Determinant computation
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\shortdefinition[Singularity] Loss of deg of Freedom $\det(\mat{J}(\vec{\theta})) = 0$
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@@ -2,7 +2,7 @@
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\begin{wrapfigure}[10]{r}{0.35\columnwidth}
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\includegraphics[width=0.35\columnwidth]{assets/inverse-kinematics.png}
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\end{wrapfigure}
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\bi{Option}: Solve Forward Kinematics for angles.\\
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\bi{Option}: Solve FK for angles.\\
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\bi{Better}: Law of cosine with polar coordinates. Compute angle using cosine rule,
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$\theta_1 = \varphi \pm \alpha$, $\theta_2 = \pm(\pi - \beta)$
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(Positive for {\color{ForestGreen} Elbow Down}, Neg. for {\color{red} Elbow Up})
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@@ -10,5 +10,5 @@ $\theta_1 = \varphi \pm \alpha$, $\theta_2 = \pm(\pi - \beta)$
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\bi{Extension to 6R}:
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1. Waist: spherical coords (2 sol.)\\
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2. 2 sols from 2R for shoulder + elbow\\
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3. Solve for wrist joints (no influence on pos)
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3. Solve for wrist joints (no infl. on pos)
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@@ -9,3 +9,11 @@
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${_B} \vec{v}_{CoM}$ vel. of CoM, ${_B}\omega$ rot. speed; both w.r.t. inert. frame
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{\scriptsize Legged robots don't need to maintain stability!}
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To determine dynamics:
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\bi{(1)} Define control inputs (e.g. wheel speeds),
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\bi{(2)} Assumptions / Simplifications about state \& inputs
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\bi{(3)} List forces, torques, etc needed,
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\bi{(4)} Express as func of states / inp
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\bi{(5)} Reduce to the CoM
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\bi{(6)} Plug into Newton-Euler eq combined with rigid body kinematics
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@@ -19,6 +19,7 @@ To compute $\vec{c}$ in $\vec{c} \cdot {_B}\vec{v}_{WB} = \omega$
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$c_i = [\sin(\alpha + \beta) \div r, -\cos(\alpha + \beta) \div r, -\cos(\beta) \cdot l \div r]$
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\newpage
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\bi{Maneuverability}
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\begin{itemize}
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\item Deg. of Mobility: $\delta_m = 3 - $\#constrained directions
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@@ -26,7 +27,6 @@ $c_i = [\sin(\alpha + \beta) \div r, -\cos(\alpha + \beta) \div r, -\cos(\beta)
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\item Deg. of Maneuverability: $\delta_M = \delta_m + \delta_s$
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\end{itemize}
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\newpage
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\shade{ForestGreen}{Wheel Configurations}
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\includegraphics[width=1\columnwidth]{assets/wheel-config.png}
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@@ -64,3 +64,10 @@ $\vec{b}_s = {\scriptsize \begin{bmatrix}
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\textit{Turning}: $\Omega = (\omega_l r_l) / R_l\! =\! (\omega_r r_r) / R_r$, $R\! =\! v / \Omega$, $\Delta \theta\! =\! \Omega \Delta t$
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\textbf{Discretized}: $\vec{x}_k = \vec{x}_{k - 1} + b_i$ with $i \in \{s, t\}$, respectively
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\textbf{Swedish Wheels}: Have 3 DoF, typ. (3 pcs) equally spaced on circle.
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Typ. Param. each: $\alpha, \beta, \gamma$ ($z$, $x$, $y$ axes, oriented along $x$, $z$ up)
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\textbf{Wheel rot speed from movement} Typ. comp: $J \cdot \mat{R}(\theta) \cdot \vec{x} = \dot{\varphi}$,
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with $\mat{R}(\theta) \cdot \vec{x}$ transform from base frame to robot frame.
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% TODO: What's the second Jacobian from?? (See 2017 exam, question B.4)
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@@ -2,8 +2,8 @@
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\bi{Meas. Model}: $\vec{z} = \vec{h}(\vec{x}) + \vec{v} + \vec{o}$, with $\vec{h}(\vec{x})$ determ. mean,
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$\vec{v}$ zero-mean noise, $\vec{o}$ unmodelled effects, $\vec{x}$ true state.
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$\vec{h}(\vec{x})$ describes how to compute $x$ from known values (e.g. Intercept-Theorem).
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Probabilistic M.M: use rand var in def, and s. \ref{sec:error-propagation}
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Probabilistic M.M: use random variable in definition, and s. \ref{sec:error-propagation}
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\bi{Motor encoders} Typ. 64-2048 incrm. per rev; Estim. rot
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\bi{Motor encoders} Typ. 64-2048 increments per rev; Estimate rot
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\bi{Rolling-Shutter} Most CMOS sensors don't take full image at once, need time stamp for each row
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@@ -40,7 +40,7 @@ If p. in diff frame, e.g. $W$-frame then $\vec{u} = \mat{K}[\mat{R}_{CW}\; {_C}\
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(Projection) $\vec{x'} = \vec{p}({_C}\vec{t}_P) = t_z^{-1} \cdot [t_x, t_y]^\top$
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(Distortion model) $r^2 = x'^2 + y'^2$, $\vec{x''} = \vec{d}(\vec{x'})$\\
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$\vec{x''} = \! \frac{1 + k_1 r^2 + k_2 r^4 + k_3 r^6}{1 + k_4 r^2 + k_5 r^4 + k_6 r^6} \vec{x'}
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$\vec{x''} = \! \frac{1 + k_1 r^2 + k_2 r^4 + k_3 r^6}{1 + k_4 r^2 + k_5 r^4 + k_6 r^6}; \vec{x'}
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+
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{\scriptsize
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\begin{bmatrix}
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