Merge pull request #190 from ven-k/vkb/mechanical-refactor

Refactors Mechanical module with `@mtkmodel`

Author: ChrisRackauckas

docs/src/connectors/connections.md

@@ -18,7 +18,7 @@ The idea behind the selection of the **through** variable is that it should be a
 ```math
 \begin{aligned}
     \partial {\color{blue}{across}} / \partial t \cdot c_1 = {\color{green}{through}}  \\
-    {\color{green}{through}} \cdot c_2 = {\color{blue}{across}} 
+    {\color{green}{through}} \cdot c_2 = {\color{blue}{across}}
 \end{aligned}
 ```
 
@@ -29,7 +29,7 @@ For the Electrical domain, the across variable is *voltage* and the through vari
   - Energy Dissipation:
 
 ```math
-\partial {\color{blue}{voltage}} / \partial t \cdot capacitance = {\color{green}{current}} 
+\partial {\color{blue}{voltage}} / \partial t \cdot capacitance = {\color{green}{current}}
 ```
 
   - Flow:
@@ -45,13 +45,13 @@ For the translation domain, choosing *velocity* for the across variable and *for
   - Energy Dissipation:
 
 ```math
-\partial {\color{blue}{velocity}} / \partial t \cdot mass = {\color{green}{force}} 
+\partial {\color{blue}{velocity}} / \partial t \cdot mass = {\color{green}{force}}
 ```
 
   - Flow:
 
 ```math
-{\color{green}{force}} \cdot (1/damping) = {\color{blue}{velocity}} 
+{\color{green}{force}} \cdot (1/damping) = {\color{blue}{velocity}}
 ```
 
 The diagram here shows the similarity of problems in different physical domains.
@@ -65,13 +65,13 @@ Now, if we choose *position* for the across variable, a similar relationship can
   - Energy Dissipation:
 
 ```math
-\partial^2 {\color{blue}{position}} / \partial t^2 \cdot mass = {\color{green}{force}} 
+\partial^2 {\color{blue}{position}} / \partial t^2 \cdot mass = {\color{green}{force}}
 ```
 
   - Flow:
 
 ```math
-{\color{green}{force}} \cdot (1/damping) = \partial {\color{blue}{position}} / \partial t 
+{\color{green}{force}} \cdot (1/damping) = \partial {\color{blue}{position}} / \partial t
 ```
 
 As can be seen, we must now establish a higher order derivative to define the Energy Dissipation and Flow equations, requiring an extra equation, as will be shown in the example below.
@@ -134,8 +134,8 @@ Now using the Translational library based on velocity, we can see the same relat
 using ModelingToolkitStandardLibrary
 const TV = ModelingToolkitStandardLibrary.Mechanical.Translational
 
-@named damping = TV.Damper(d = 1, v_a_0 = 1)
-@named body = TV.Mass(m = 1, v_0 = 1)
+@named damping = TV.Damper(d = 1, flange_a.v = 1)
+@named body = TV.Mass(m = 1, v = 1)
 @named ground = TV.Fixed()
 
 eqs = [connect(damping.flange_a, body.flange)
@@ -167,8 +167,8 @@ Now, let's consider the position-based approach.  We can build the same model wi
 ```@example connections
 const TP = ModelingToolkitStandardLibrary.Mechanical.TranslationalPosition
 
-@named damping = TP.Damper(d = 1, v_a_0 = 1)
-@named body = TP.Mass(m = 1, v_0 = 1)
+@named damping = TP.Damper(d = 1, va = 1, vb = 0.0)
+@named body = TP.Mass(m = 1, v = 1)
 @named ground = TP.Fixed(s_0 = 0)
 
 eqs = [connect(damping.flange_a, body.flange)
@@ -197,10 +197,10 @@ plot(p1, p2, p3)
 
 The question then arises, can the position be plotted when using the Mechanical Translational Domain based on the Velocity Across variable?  Yes, we can!  There are 2 solutions:
 
- 1. the `Mass` component will add the position variable when the `s_0` parameter is used to set an initial position. Otherwise, the component does not track the position.
+ 1. the `Mass` component will add the position variable when the `s` parameter is used to set an initial position. Otherwise, the component does not track the position.
 
 ```julia
-@named body = TV.Mass(m = 1, v_0 = 1, s_0 = 0)
+@named body = TV.Mass(m = 1, v = 1, s = 0)
 ```
 
  2. implement a `PositionSensor`
@@ -220,31 +220,31 @@ In this problem, we have a mass, spring, and damper which are connected to a fix
 
 #### Damper
 
-The damper will connect the flange/flange 1 (`flange_a`) to the mass, and flange/flange 2 (`flange_b`) to the fixed point.  For both position- and velocity-based domains, we set the damping constant `d=1` and `v_a_0=1` and leave the default for `v_b_0` at 0.  For the position domain, we also need to set the initial positions for `flange_a` and `flange_b`.
+The damper will connect the flange/flange 1 (`flange_a`) to the mass, and flange/flange 2 (`flange_b`) to the fixed point.  For both position- and velocity-based domains, we set the damping constant `d=1` and `va=1` and leave the default for `v_b_0` at 0.  For the position domain, we also need to set the initial positions for `flange_a` and `flange_b`.
 
 ```@example connections
-@named dv = TV.Damper(d = 1, v_a_0 = 1)
-@named dp = TP.Damper(d = 1, v_a_0 = 1, s_a_0 = 3, s_b_0 = 1)
+@named dv = TV.Damper(d = 1, flange_a.v = 1)
+@named dp = TP.Damper(d = 1, va = 1, vb = 0.0, flange_a__s = 3, flange_b__s = 1)
 nothing # hide
 ```
 
 #### Spring
 
-The spring will connect the flange/flange 1 (`flange_a`) to the mass, and flange/flange 2 (`flange_b`) to the fixed point.  For both position- and velocity-based domains, we set the spring constant `k=1`.  The velocity domain then requires the initial velocity `v_a_0` and initial spring stretch `delta_s_0`.  The position domain instead needs the initial positions for `flange_a` and `flange_b` and the natural spring length `l`.
+The spring will connect the flange/flange 1 (`flange_a`) to the mass, and flange/flange 2 (`flange_b`) to the fixed point.  For both position- and velocity-based domains, we set the spring constant `k=1`.  The velocity domain then requires the initial velocity `va` and initial spring stretch `delta_s`.  The position domain instead needs the initial positions for `flange_a` and `flange_b` and the natural spring length `l`.
 
 ```@example connections
-@named sv = TV.Spring(k = 1, v_a_0 = 1, delta_s_0 = 1)
-@named sp = TP.Spring(k = 1, s_a_0 = 3, s_b_0 = 1, l = 1)
+@named sv = TV.Spring(k = 1, flange_a__v = 1, delta_s = 1)
+@named sp = TP.Spring(k = 1, flange_a__s = 3, flange_b__s = 1, l = 1)
 nothing # hide
 ```
 
 #### Mass
 
-For both position- and velocity-based domains, we set the mass `m=1` and initial velocity `v_0=1`. Like the damper, the position domain requires the position initial conditions set as well.
+For both position- and velocity-based domains, we set the mass `m=1` and initial velocity `v=1`. Like the damper, the position domain requires the position initial conditions set as well.
 
 ```@example connections
-@named bv = TV.Mass(m = 1, v_0 = 1)
-@named bp = TP.Mass(m = 1, v_0 = 1, s_0 = 3)
+@named bv = TV.Mass(m = 1, v = 1)
+@named bp = TP.Mass(m = 1, v = 1, s = 3)
 nothing # hide
 ```
 

src/Hydraulic/IsothermalCompressible/components.jl

@@ -506,7 +506,7 @@ dm ────►               │  │ area
 
     ports = @named begin
         port = HydraulicPort(; p_int)
-        flange = MechanicalPort(; f_int = p_int * area)
+        flange = MechanicalPort(; f = p_int * area)
         damper = ValveBase(; p_a_int = p_int, p_b_int = p_int, area_int = 1, Cd,
             Cd_reverse, minimum_area)
     end

src/Mechanical/MultiBody2D/components.jl

@@ -1,14 +1,14 @@
-@component function Link(; name, m, l, I, g, x1_0 = 0, y1_0 = 0)
-    pars = @parameters begin
-        m = m
-        l = l
-        I = I
-        g = g
-        x1_0 = x1_0
-        y1_0 = y1_0
+@mtkmodel Link begin
+    @parameters begin
+        m
+        l
+        I
+        g
+        x1_0 = 0.0
+        y1_0 = 0.0
     end
 
-    vars = @variables begin
+    @variables begin
         (A(t) = 0), [state_priority = 10]
         (dA(t) = 0), [state_priority = 10]
         (ddA(t) = 0), [state_priority = 10]
@@ -40,13 +40,16 @@
         ddy_cm(t) = 0
     end
 
-    @named TX1 = MechanicalPort()
-    @named TY1 = MechanicalPort()
+    @components begin
+        TX1 = MechanicalPort()
+        TY1 = MechanicalPort()
 
-    @named TX2 = MechanicalPort()
-    @named TY2 = MechanicalPort()
+        TX2 = MechanicalPort()
+        TY2 = MechanicalPort()
+    end
 
-    eqs = [D(A) ~ dA
+    @equations begin
+        D(A) ~ dA
         D(dA) ~ ddA
         D(x1) ~ dx1
         D(y1) ~ dy1
@@ -57,17 +60,17 @@
         D(y_cm) ~ dy_cm
         D(dy_cm) ~ ddy_cm
 
-    # x forces
+        # x forces
         m * ddx_cm ~ fx1 + fx2
 
-    # y forces
+        # y forces
         m * ddy_cm ~ m * g + fy1 + fy2
 
-    # torques
+        # torques
         I * ddA ~ -fy1 * (x2 - x1) / 2 + fy2 * (x2 - x1) / 2 + fx1 * (y2 - y1) / 2 -
                   fx2 * (y2 - y1) / 2
 
-    # geometry
+        # geometry
         x2 ~ l * cos(A) + x1
         y2 ~ l * sin(A) + y1
         x_cm ~ l * cos(A) / 2 + x1
@@ -79,8 +82,6 @@
         TX2.f ~ fx2
         TX2.v ~ dx2
         TY2.f ~ fy2
-        TY2.v ~ dy2]
-
-    return ODESystem(eqs, t, vars, pars; name = name, systems = [TX1, TY1, TX2, TY2],
-        defaults = [TX1.v => 0, TY1.v => 0, TX2.v => 0, TY2.v => 0])
+        TY2.v ~ dy2
+    end
 end