refactor: Mechanical/translational.jl

Author: ven-k

src/Mechanical/Translational/Translational.jl

@@ -4,6 +4,7 @@ Library to model 1-dimensional, translational mechanical systems
 module Translational
 
 using ModelingToolkit, Symbolics
+using ModelingToolkit: getdefault
 
 using ModelingToolkitStandardLibrary.Blocks: RealInput, RealOutput
 using IfElse: ifelse

src/Mechanical/Translational/components.jl

@@ -7,30 +7,34 @@ Use to close a system that has un-connected `MechanicalPort`'s where the force s
 
   - `flange`: 1-dim. translational flange
 """
-@component function Free(; name)
-    @named flange = MechanicalPort()
-    vars = @variables f(t) = 0
-    eqs = [
-        flange.f ~ f,
-    ]
-    return compose(ODESystem(eqs, t, vars, []; name, defaults = [flange.v => 0]),
-        flange)
+@mtkmodel Free begin
+    @components begin
+        flange = MechanicalPort()
+    end
+    @variables begin
+        f(t) = 0.0
+    end
+    @equations begin
+        flange.f ~ f
+    end
 end
 
 """
-    Fixed(;name)
+    Fixed(; name)
 
 Fixes a flange position (velocity = 0)
 
 # Connectors:
 
   - `flange`: 1-dim. translational flange
 """
-@component function Fixed(; name)
-    @named flange = MechanicalPort()
-    eqs = [flange.v ~ 0]
-    return compose(ODESystem(eqs, t, [], []; name = name, defaults = [flange.v => 0]),
-        flange)
+@mtkmodel Fixed begin
+    @components begin
+        flange = MechanicalPort()
+    end
+    @equations begin
+        flange.v ~ 0
+    end
 end
 
 """
@@ -175,41 +179,37 @@ const ABS = Val(:absolute)
 end
 
 """
-    Damper(; name, d, v_a_0=0.0, v_b_0=0.0)
+    Damper(; name, d, flange_a.v = 0.0, flange_b.v = 0.0)
 
 Linear 1D translational damper
 
 # Parameters:
 
   - `d`: [N.s/m] Damping constant
-  - `v_a_0`: [m/s] Initial value of absolute linear velocity at flange_a (default 0 m/s)
-  - `v_b_0`: [m/s] Initial value of absolute linear velocity at flange_b (default 0 m/s)
 
 # Connectors:
 
-  - `flange_a`: 1-dim. translational flange on one side of damper
-  - `flange_b`: 1-dim. translational flange on opposite side of damper
+  - `flange_a`: 1-dim. translational flange on one side of damper. Initial value of state `v` is set to 0.0 m/s.
+  - `flange_b`: 1-dim. translational flange on opposite side of damper. Initial value of state `v` is set to 0.0 m/s.
 """
-@component function Damper(; name, d, v_a_0 = 0.0, v_b_0 = 0.0)
-    pars = @parameters begin
-        d = d
-        v_a_0 = v_a_0
-        v_b_0 = v_b_0
+@mtkmodel Damper begin
+    @parameters begin
+        d
     end
-    vars = @variables begin
-        v(t) = v_a_0 - v_b_0
+    @variables begin
+        v(t)
         f(t) = 0.0
     end
 
-    @named flange_a = MechanicalPort()
-    @named flange_b = MechanicalPort()
+    @components begin
+        flange_a = MechanicalPort(; v = 0.0)
+        flange_b = MechanicalPort(; v = 0.0)
+    end
 
-    eqs = [v ~ flange_a.v - flange_b.v
+    @equations begin
+        v ~ flange_a.v - flange_b.v
         f ~ v * d
         flange_a.f ~ +f
-        flange_b.f ~ -f]
-    return compose(ODESystem(eqs, t, vars, pars; name = name,
-            defaults = [flange_a.v => v_a_0, flange_b.v => v_b_0]),
-        flange_a,
-        flange_b) #flange_a.f => +(v_a_0 - v_b_0)*d, flange_b.f => -(v_a_0 - v_b_0)*d
+        flange_b.f ~ -f
+    end
 end

src/Mechanical/Translational/sensors.jl

@@ -8,47 +8,45 @@ Linear 1D force input sensor.
   - `flange`: 1-dim. translational flange
   - `output`: real output
 """
-@component function ForceSensor(; name)
-    systems = @named begin
+@mtkmodel ForceSensor begin
+    @components begin
         flange = MechanicalPort()
         output = RealOutput()
     end
 
-    vars = pars = []
-    eqs = [
-        flange.f ~ -output.u,
-    ]
-
-    ODESystem(eqs, t, vars, pars; name, systems)
+    @equations begin
+        flange.f ~ -output.u
+    end
 end
 
 """
-    PositionSensor(; s_0 = 0, name)
+    PositionSensor(; s = 0, name)
 
 Linear 1D position input sensor.
 
-# Parameters:
+# States:
 
-- `s_0`: [m] initial value of absolute position
+- `s`: [m] absolute position (with initial value of 0.0)
 
 # Connectors:
 
   - `flange`: 1-dim. translational flange
   - `output`: real output
 """
-@component function PositionSensor(; s_0 = 0, name)
-    systems = @named begin
+@mtkmodel PositionSensor begin
+    @components begin
         flange = MechanicalPort()
         output = RealOutput()
     end
 
-    pars = @parameters s_0 = s_0
-    vars = @variables s(t) = s_0
+    @variables begin
+        s(t) = 0.0
+    end
 
-    eqs = [D(s) ~ flange.v
+    @equations begin
+        D(s) ~ flange.v
         output.u ~ s
-        flange.f ~ 0]
+        flange.f ~ 0.0
+    end
 
-    ODESystem(eqs, t, vars, pars; name, systems,
-        defaults = [flange.v => 0, output.u => s_0])
 end

src/Mechanical/Translational/sources.jl

@@ -6,84 +6,76 @@ Linear 1D force input source
 # Connectors:
 
   - `flange`: 1-dim. translational flange
-  - `f`: real input 
+  - `f`: real input
 """
-@component function Force(; name)
-    systems = @named begin
-        flange = MechanicalPort()
+@mtkmodel Force begin
+    @components begin
+        flange = MechanicalPort(; v = 0.0)
         f = RealInput()
     end
 
-    vars = pars = []
-    eqs = [
-        flange.f ~ -f.u,
-    ]
-
-    ODESystem(eqs, t, vars, pars; name, systems, defaults = [flange.v => 0])
+    @equations begin
+        flange.f ~ -f.u
+    end
 end
 
 """
-    Position(; s_0 = 0, name)
+    Position(; s.u_start = 0.0, name)
 
 Linear 1D position input source
 
-# Parameters:
-
-- `s_0`: [m] initial value of absolute position
-
 # Connectors:
 
   - `flange`: 1-dim. translational flange
-  - `s`: real input 
+  - `s`: real input. `s.u_start` accepts initial value and defaults to 0.0.
 """
-@component function Position(solves_force = true; s_0 = 0, name)
-    systems = @named begin
-        flange = MechanicalPort()
-        s = RealInput()
+@mtkmodel Position begin
+    @parameters begin
+        solves_force = false
+    end
+    @components begin
+        flange = MechanicalPort(; v = 0.0)
+        s = RealInput(; u_start = 0.0)
+    end
+    @variables begin
+        x(t)
+    end
+    @equations begin
+        D(x) ~ flange.v
+        s.u ~ x
+        !getdefault(solves_force) && 0 ~ flange.f
     end
-
-    pars = @parameters s_0 = s_0
-    vars = @variables x(t) = s_0
-
-    eqs = [D(x) ~ flange.v
-        s.u ~ x]
-
-    !solves_force && push!(eqs, 0 ~ flange.f)
-
-    ODESystem(eqs, t, vars, pars; name, systems, defaults = [flange.v => 0, s.u => s_0])
 end
 
-@component function Velocity(solves_force = true; name)
-    systems = @named begin
+@mtkmodel Velocity begin
+    @parameters begin
+        solves_force = false
+    end
+    @components begin
         flange = MechanicalPort()
         v = RealInput()
     end
-
-    pars = []
-    vars = []
-
-    eqs = [
-        v.u ~ flange.v,
-    ]
-
-    !solves_force && push!(eqs, 0 ~ flange.f)
-
-    ODESystem(eqs, t, vars, pars; name, systems, defaults = [flange.v => 0])
+    @equations begin
+        v.u ~ flange.v
+        getdefault(solves_force) && 0 ~ flange.f
+    end
 end
 
-@component function Acceleration(solves_force = true; s_0 = 0, name)
-    systems = @named begin
-        flange = MechanicalPort()
+@mtkmodel Acceleration begin
+    @parameters begin
+        solves_force = false
+    end
+    @components begin
+        flange = MechanicalPort(; v = 0.0)
         a = RealInput()
     end
+    @variables begin
+        v(t) = 0
+    end
 
-    pars = []
-    vars = @variables v(t) = 0
-
-    eqs = [v ~ flange.v
-        D(v) ~ a.u]
-
-    !solves_force && push!(eqs, 0 ~ flange.f)
-
-    ODESystem(eqs, t, vars, pars; name, systems, defaults = [flange.v => 0])
+    @equations begin
+        v ~ flange.v
+        D(v) ~ a.u
+        !getdefault(solves_force) && 0 ~ flange.f
+    end
 end

src/Mechanical/Translational/utils.jl

@@ -1,13 +1,6 @@
-@connector function MechanicalPort(; name, f_int = 0, v_int = 0)
-    pars = @parameters begin
-        f_int = f_int
-        v_int = v_int
-    end
-    vars = @variables begin
-        v(t) = v_int
-        f(t), [connect = Flow]
-    end
-    ODESystem(Equation[], t, vars, pars; name, defaults = [f => f_int])
+@connector MechanicalPort begin
+    v(t) = 0.0
+    f(t) = 0.0, [connect = Flow]
 end
 Base.@doc """
     MechanicalPort(;name)

test/Mechanical/translational.jl

@@ -10,8 +10,8 @@ D = Differential(t)
 @testset "Free" begin
     function System(; name)
         systems = @named begin
-            acc = TV.Acceleration(false)
-            a = Constant(k = -10)
+            acc = TV.Acceleration()
+            a = Constant(; k = -10)
             mass = TV.Mass(; m = 100)
             free = TV.Free()
         end
@@ -33,7 +33,7 @@ D = Differential(t)
 end
 
 @testset "spring damper mass fixed" begin
-    @named dv = TV.Damper(d = 1, v_a_0 = 1)
+    @named dv = TV.Damper(d = 1, flange_a.v = 1)
     @named dp = TP.Damper(d = 1, v_a_0 = 1, s_a_0 = 3, s_b_0 = 1)
 
     @named sv = TV.Spring(k = 1, v_a_0 = 1, delta_s_0 = 1)
@@ -70,7 +70,7 @@ end
 end
 
 @testset "driven spring damper mass" begin
-    @named dv = TV.Damper(d = 1, v_a_0 = 1)
+    @named dv = TV.Damper(d = 1, flange_a.v = 1)
     @named dp = TP.Damper(d = 1, v_a_0 = 1, s_a_0 = 3, s_b_0 = 1)
 
     @named sv = TV.Spring(k = 1, v_a_0 = 1, delta_s_0 = 1)
@@ -119,8 +119,8 @@ end
 @testset "sources & sensors" begin
     function System(; name)
         systems = @named begin
-            pos = TV.Position(; s_0 = 0)
-            pos_sensor = TV.PositionSensor(; s_0 = 1)
+            pos = TV.Position(; s.u_start = 0)
+            pos_sensor = TV.PositionSensor(; s = 1)
             force = TV.Force()
             force_sensor = TV.ForceSensor()