From da36cc0ea9c341f491655c444ee21396e37dc00f Mon Sep 17 00:00:00 2001
From: "E. A. Graham Jr." <10370165+EAGrahamJr@users.noreply.github.com>
Date: Tue, 21 May 2024 12:27:56 -0700
Subject: [PATCH] Fix stepper gear ratios.

Math was totally wrong and the tests were inverted to match the wrongness.
---
 .../crackers/kobots/parts/movement/Rotator.kt | 12 ++-----
 .../kobots/parts/movement/RotatorTest.kt      | 31 ++++++++++++++-----
 2 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/src/main/kotlin/crackers/kobots/parts/movement/Rotator.kt b/src/main/kotlin/crackers/kobots/parts/movement/Rotator.kt
index ed15702..709fa19 100644
--- a/src/main/kotlin/crackers/kobots/parts/movement/Rotator.kt
+++ b/src/main/kotlin/crackers/kobots/parts/movement/Rotator.kt
@@ -72,23 +72,17 @@ open class BasicStepperRotator(
     val stepStyle: StepStyle = StepStyle.SINGLE
 ) : Rotator, StepperActuator {
 
-    private val maxSteps: Float
-
     private val degreesToSteps: Map<Int, Int>
     private val stepsToDegrees = mutableMapOf<Int, MutableList<Int>>()
 
     init {
         require(gearRatio > 0f) { "gearRatio '$gearRatio' must be greater than zero." }
-        maxSteps = theStepper.stepsPerRotation / gearRatio
+        val stepRatio = theStepper.stepsPerRotation * gearRatio / 360
 
         // calculate how many steps off of "zero" each degree is
         degreesToSteps = (0..359).map { deg: Int ->
-            val steps = (maxSteps * deg / 360).roundToInt()
-            stepsToDegrees.compute(steps) { _, v ->
-                val theList = v ?: mutableListOf()
-                theList += deg
-                theList
-            }
+            val steps = (deg * stepRatio).roundToInt()
+            stepsToDegrees.compute(steps) { _, v -> (v ?: mutableListOf()).apply { add(deg) } }
             deg to steps
         }.toMap()
     }
diff --git a/src/test/kotlin/crackers/kobots/parts/movement/RotatorTest.kt b/src/test/kotlin/crackers/kobots/parts/movement/RotatorTest.kt
index 14da09d..054ad0f 100644
--- a/src/test/kotlin/crackers/kobots/parts/movement/RotatorTest.kt
+++ b/src/test/kotlin/crackers/kobots/parts/movement/RotatorTest.kt
@@ -53,7 +53,7 @@ class RotatorTest : FunSpec(
              * The gear ratio is 1:1 and the stepper motor has 200 steps per rotation. The rotator is set to move from
              * 0 to 360 degrees, and it's starting position is assumed to be 0 degrees. The target angle is 83 degrees.
              */
-            test("max steps < 360, 1:1 gear ratio") {
+            test("stepper 200, 1:1 gear ratio, 83 deg") {
                 every { mockStepper.stepsPerRotation } answers { 200 }
                 val rotor = BasicStepperRotator(mockStepper)
 
@@ -64,12 +64,12 @@ class RotatorTest : FunSpec(
             }
 
             /**
-             * With a gear ratio of 1:1.11 and the motor has 200 steps per rotation. The rotator is to be moved 90
+             * With a gear ratio of .9 and the motor has 200 steps per rotation. The rotator is to be moved 90
              * degrees in a forward direction. The stepper is currently at 0 degrees.
              */
-            test("max steps < 360, 1:11:1 gear ratio") {
+            test("steooer 200, .9 gear ratio, 90 deg") {
                 every { mockStepper.stepsPerRotation } answers { 200 }
-                val rotor = BasicStepperRotator(mockStepper, 1.11f)
+                val rotor = BasicStepperRotator(mockStepper, .9f)
 
                 rotor.test(90)
                 verify(exactly = 45) {
@@ -78,15 +78,30 @@ class RotatorTest : FunSpec(
             }
 
             /**
-             * Motor has 2048 steps per rotation and a gear ratio of 1.28 (simulated from real-world). The target is
+             * With a gear ratio of 2.5 and the motor has 200 steps per rotation. The rotator is to be moved 45
+             * degrees in a forward direction. The stepper is currently at 0 degrees.
+             */
+            test("stepper 200, 2.5 gear ratio, 45 deg") {
+                every { mockStepper.stepsPerRotation } answers { 200 }
+
+                val rotor = BasicStepperRotator(mockStepper, 2.5f)
+
+                rotor.test(45)
+                verify(atMost = 63, atLeast = 62) {
+                    mockStepper.step(StepperMotorInterface.Direction.FORWARD, any())
+                }
+            }
+
+            /**
+             * Motor has 2048 steps per rotation and a gear ratio of .78 (simulated from real-world). The target is
              * 90 degrees.
              */
-            test("max steps > 360, 1.28:1 gear ratio") {
+            test("stepper 2048, .78 gear ratio, 90 deg") {
                 every { mockStepper.stepsPerRotation } answers { 2048 }
-                val rotor = BasicStepperRotator(mockStepper, 1.28f)
+                val rotor = BasicStepperRotator(mockStepper, .78f)
 
                 rotor.test(90)
-                verify(exactly = 400) {
+                verify(atLeast = 398, atMost = 400) {
                     mockStepper.step(StepperMotorInterface.Direction.FORWARD, any())
                 }
             }