Close kinematic loops: driven joints move four-bars and sliders (#1141)
Driven joints now solve closed kinematic loops, so a four-bar or slider-crank moves as a whole when one joint is driven.
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Mateusz Sych authored and GitHub committed
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@@ -295,3 +295,428 @@ fn interference_box_sweep_matches_every_pair_check() {
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let (pairs, skipped) = super::overlapping_pairs(&boxes, 10);
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assert_eq!((pairs.len(), skipped), (10, every.len() - 10));
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}
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/// A small block in a new component: a part of a linkage, where only its joints matter.
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fn part(s: &mut Session, name: &str, corner: [f64; 3]) {
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run(s, "component.activate", json!({"component": "root"}));
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run(s, "component.create", json!({"name": name}));
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run(s, "solid.box", json!({"length": 2, "width": 2, "height": 2, "corner": corner}));
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}
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/// A joint between two parts as they are, at a world point with its z along `z`.
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fn pin(s: &mut Session, kind: &str, name: &str, a: &str, b: &str, p: Vec3, z: Vec3) {
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let at = |o: &str| json!({"occurrence": o, "point": [p.x, p.y, p.z], "z": [z.x, z.y, z.z]});
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let r = run(s, "joint.create", json!({"type": kind, "a": at(a), "b": at(b), "flip": true, "name": name}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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}
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/// Where circles about `p` (radius `r`) and `q` (radius `s`) in the XY plane meet.
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fn meet(p: Vec3, r: f64, q: Vec3, s: f64) -> [Vec3; 2] {
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let d = q - p;
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let l = d.len();
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let a = (r * r - s * s + l * l) / (2.0 * l);
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let m = p + d * (a / l);
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let n = Vec3::new(-d.y, d.x, 0.0) * ((r * r - a * a).max(0.0).sqrt() / l);
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[m + n, m - n]
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}
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/// A crank-rocker four-bar about +Z: ground pivots O2 = (0, 0) and O4 = (45, 0), crank 20,
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/// coupler 50, rocker 40, assembled with the crank at 90°. Returns the crank pin P0 and the
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/// rocker pin Q0 (the upper, open assembly).
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fn four_bar() -> (Session, Vec3, Vec3) {
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let mut s = Session::default();
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let (o2, o4, p0) = (Vec3::ZERO, Vec3::new(45.0, 0.0, 0.0), Vec3::new(0.0, 20.0, 0.0));
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let [q0, _] = meet(p0, 50.0, o4, 40.0);
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for (name, c) in [("Ground", o2), ("Crank", p0), ("Coupler", (p0 + q0) * 0.5), ("Rocker", q0)] {
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part(&mut s, name, [c.x, c.y, -5.0]);
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}
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let g = occ(&s, "Ground");
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run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
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pin(&mut s, "revolute", "Crank", "Ground", "Crank", o2, Vec3::Z);
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pin(&mut s, "revolute", "Crank pin", "Crank", "Coupler", p0, Vec3::Z);
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pin(&mut s, "revolute", "Rocker pin", "Coupler", "Rocker", q0, Vec3::Z);
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pin(&mut s, "revolute", "Rocker", "Ground", "Rocker", o4, Vec3::Z);
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(s, p0, q0)
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}
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/// The four-bar's rocker pin with the crank driven to `to`°, followed a degree at a time from
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/// `from`° (where it is at `q`), so it stays on its branch.
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fn rocker_pin(from: f64, to: f64, mut q: Vec3) -> Vec3 {
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let n = ((to - from).abs().ceil() as usize).max(1);
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for k in 1..=n {
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let th = (90.0 + from + (to - from) * k as f64 / n as f64).to_radians();
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let [m1, m2] = meet(Vec3::new(20.0 * th.cos(), 20.0 * th.sin(), 0.0), 50.0, Vec3::new(45.0, 0.0, 0.0), 40.0);
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q = if m1.dist(q) <= m2.dist(q) { m1 } else { m2 };
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}
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q
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}
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#[test]
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fn four_bar_follows_its_crank() {
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let (mut s, p0, q0) = four_bar();
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let mut q = q0;
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let mut at_330 = q0;
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for k in 1..=12 {
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let v = 30.0 * f64::from(k);
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let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": v}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{v}°: {r}");
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assert!(r["stopped_by_loop"].is_null(), "{v}°: {r}");
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// The driven joint keeps exactly the value asked for.
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assert!((r["values"][0].as_f64().unwrap_or(f64::NAN) - v.to_radians()).abs() < 1e-12, "{r}");
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q = rocker_pin(v - 30.0, v, q);
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let th = (90.0 + v).to_radians();
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let p = Vec3::new(20.0 * th.cos(), 20.0 * th.sin(), 0.0);
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for (part, local, want) in [("Crank", p0, p), ("Coupler", p0, p), ("Coupler", q0, q), ("Rocker", q0, q)] {
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assert!(near(place(&s, part, local), want), "{v}°: {part} {:?} wants {want:?}", place(&s, part, local));
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}
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if k == 11 {
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at_330 = q;
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}
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}
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// Back where it started after a full turn, and undo steps back.
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assert!(near(q, q0));
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run(&mut s, "edit.undo", json!({}));
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assert!(near(place(&s, "Rocker", q0), at_330), "{:?}", place(&s, "Rocker", q0));
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// One 180° drive lands on the same (open) branch as the stepped path.
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let (mut s, _, q0) = four_bar();
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let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": 180}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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assert!(near(place(&s, "Rocker", q0), rocker_pin(0.0, 180.0, q0)), "{:?}", place(&s, "Rocker", q0));
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// A motion study playing the crank places the rocker the same way.
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run(&mut s, "motion.study", json!({"name": "Turn", "steps": 10, "keys": [{"joint": "Crank", "points": [[0, 0], [10, 120]]}]}));
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let r = run(&mut s, "motion.play", json!({"study": "Turn", "step": 5}));
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assert!(r["stopped_by_loop"].is_null(), "{r}");
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assert!(near(place(&s, "Rocker", q0), rocker_pin(180.0, 60.0, rocker_pin(0.0, 180.0, q0))), "{:?}", place(&s, "Rocker", q0));
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}
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/// The rocker swings between its toggle positions, where crank and coupler line up (|Q| = 70
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/// and |Q| = 30, about 69.3° and 139.2° from the ground line); driving it further stops where
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/// the loop still closes.
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#[test]
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fn four_bar_rocker_stops_where_the_loop_cannot_close() {
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let (mut s, _, q0) = four_bar();
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let start = q0.y.atan2(q0.x - 45.0).to_degrees();
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let r = run(&mut s, "joint.drive", json!({"joint": "Rocker", "value": 100}));
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assert!(r["stopped_by_loop"].is_object(), "{r}");
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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let reached = r["values"][0].as_f64().unwrap_or(f64::NAN).to_degrees();
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// |Q|² = 45² + 40² + 2·45·40·cos φ = 30².
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let limit = ((900.0f64 - 3625.0) / 3600.0).acos().to_degrees() - start;
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assert!(reached > limit - 5.0 && reached <= limit, "stopped at {reached}°, the limit is {limit}°");
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// Inside its swing it moves freely, and the crank follows.
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let r = run(&mut s, "joint.drive", json!({"joint": "Rocker", "value": -10}));
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assert!(r["stopped_by_loop"].is_null() && r["conflicts"].as_array().map(Vec::len) == Some(0), "{r}");
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let q = place(&s, "Rocker", q0);
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assert!((q.y.atan2(q.x - 45.0).to_degrees() - (start - 10.0)).abs() < 1e-6, "{q:?}");
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assert!(place(&s, "Coupler", q0).dist(q) < 1e-6);
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// A full turn would end where it started, but the rocker can't get there.
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let (mut s, _, _) = four_bar();
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let r = run(&mut s, "joint.drive", json!({"joint": "Rocker", "value": 360}));
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assert!(r["stopped_by_loop"].is_object(), "{r}");
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assert!(r["values"][0].as_f64().unwrap_or(f64::NAN).to_degrees() <= limit, "{r}");
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}
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/// A loop value a motion link sets follows through the start of its link chain: a dial outside
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/// the loop turns a gear, which sets the rocker's angle, so turning the crank turns the dial.
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#[test]
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fn four_bar_turns_the_source_of_a_linked_loop_value() {
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let linked = || {
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let (mut s, _, q0) = four_bar();
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for (name, x) in [("Dial", 80.0), ("Gear", 100.0)] {
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part(&mut s, name, [x, 0.0, -5.0]);
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pin(&mut s, "revolute", name, "Ground", name, Vec3::new(x, 0.0, 0.0), Vec3::Z);
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}
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run(&mut s, "joint.motion_link", json!({"a": "Dial", "b": "Gear", "ratio": 1}));
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run(&mut s, "joint.motion_link", json!({"a": "Gear", "b": "Rocker", "ratio": 0.5}));
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(s, q0)
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};
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let (mut s, q0) = linked();
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let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": 60}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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let q = rocker_pin(0.0, 60.0, q0);
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assert!(near(place(&s, "Rocker", q0), q), "{:?} wants {q:?}", place(&s, "Rocker", q0));
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let turn = q.y.atan2(q.x - 45.0) - q0.y.atan2(q0.x - 45.0);
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let dial = s.doc.assembly.joints.iter().find(|j| j.name == "Dial").and_then(|j| j.values.first().copied()).unwrap_or(f64::NAN);
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assert!((dial - 2.0 * turn).abs() < 1e-9, "dial {dial}, rocker turned {turn}");
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// Driving the dial drives the rocker through the chain: two turns of the dial would turn
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// the rocker a full turn, which it can't make.
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let (mut s, _) = linked();
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let r = run(&mut s, "joint.drive", json!({"joint": "Dial", "value": 720}));
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assert!(r["stopped_by_loop"].is_object(), "{r}");
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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}
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/// Values left out of a drive are free to follow in a loop: a plate on a planar joint whose
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/// travel a diagonal slider limits. Driving only the planar joint's x moves its y along.
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#[test]
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fn values_left_out_of_a_drive_follow_the_loop() {
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let mut s = Session::default();
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part(&mut s, "Ground", [-1.0, -1.0, -5.0]);
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part(&mut s, "Plate", [-1.0, -1.0, 0.0]);
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let g = occ(&s, "Ground");
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run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
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let frame = |o: &str, z: [f64; 3], x: [f64; 3]| json!({"occurrence": o, "frame": {"origin": [0, 0, 0], "z": z, "x": x}});
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let flat = |o: &str| frame(o, [0.0, 0.0, 1.0], [1.0, 0.0, 0.0]);
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let r = run(&mut s, "joint.create", json!({"type": "planar", "a": flat("Ground"), "b": flat("Plate"), "flip": true, "name": "Table"}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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let diagonal = |o: &str| frame(o, [1.0, 1.0, 0.0], [0.0, 0.0, 1.0]);
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let r = run(&mut s, "joint.create", json!({"type": "slider", "a": diagonal("Ground"), "b": diagonal("Plate"), "flip": true, "name": "Rail"}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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let r = run(&mut s, "joint.drive", json!({"joint": "Table", "values": [10]}));
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assert!(r["stopped_by_loop"].is_null() && r["conflicts"].as_array().map(Vec::len) == Some(0), "{r}");
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assert!(near(place(&s, "Plate", Vec3::ZERO), Vec3::new(10.0, 10.0, 0.0)), "{:?}", place(&s, "Plate", Vec3::ZERO));
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}
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/// A slider-crank: crank 15 about the origin, rod 40, a piston sliding along X. The piston
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/// sits at a·cos θ + √(b² − (a·sin θ)²).
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#[test]
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fn slider_crank_moves_the_piston() {
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let mut s = Session::default();
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let (o, p0) = (Vec3::ZERO, Vec3::new(0.0, 15.0, 0.0));
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let s0 = Vec3::new((40.0f64 * 40.0 - 15.0 * 15.0).sqrt(), 0.0, 0.0);
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for (name, c) in [("Ground", o), ("Crank", p0), ("Rod", s0 * 0.5), ("Piston", s0)] {
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part(&mut s, name, [c.x, c.y, -5.0]);
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}
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let g = occ(&s, "Ground");
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run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
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pin(&mut s, "revolute", "Crank", "Ground", "Crank", o, Vec3::Z);
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pin(&mut s, "revolute", "Crank pin", "Crank", "Rod", p0, Vec3::Z);
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pin(&mut s, "revolute", "Wrist pin", "Rod", "Piston", s0, Vec3::Z);
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pin(&mut s, "slider", "Bore", "Ground", "Piston", s0, Vec3::X);
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for v in [40.0, 135.0, 270.0] {
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let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": v}));
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{v}°: {r}");
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let th = (90.0f64 + v).to_radians();
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let x = 15.0 * th.cos() + (40.0f64.powi(2) - (15.0 * th.sin()).powi(2)).sqrt();
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assert!(near(place(&s, "Piston", s0), Vec3::new(x, 0.0, 0.0)), "{v}°: {:?} wants x = {x}", place(&s, "Piston", s0));
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assert!(near(place(&s, "Rod", p0), Vec3::new(15.0 * th.cos(), 15.0 * th.sin(), 0.0)));
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}
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}
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/// A joint frame on an occurrence, by origin and axes.
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fn framed(o: &str, origin: [f64; 3], z: [f64; 3], x: [f64; 3]) -> Value {
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json!({"occurrence": o, "frame": {"origin": origin, "z": z, "x": x}})
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}
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/// A loop open from the start closes from where it is: an arm on a revolute joint, and a rigid
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/// joint that wants it turned 90°.
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#[test]
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fn an_open_loop_closes_from_where_it_is() {
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let mut s = Session::default();
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part(&mut s, "Ground", [-1.0, -1.0, -5.0]);
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part(&mut s, "Arm", [0.0, -1.0, 0.0]);
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let g = occ(&s, "Ground");
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run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
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pin(&mut s, "revolute", "Pivot", "Ground", "Arm", Vec3::ZERO, Vec3::Z);
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let r = run(
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&mut s,
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"joint.create",
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json!({"type": "rigid", "a": framed("Ground", [0.0; 3], [0.0, 0.0, 1.0], [0.0, 1.0, 0.0]),
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"b": framed("Arm", [0.0; 3], [0.0, 0.0, 1.0], [1.0, 0.0, 0.0]), "flip": true, "name": "Lock"}),
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);
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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assert!(near(place(&s, "Arm", Vec3::new(10.0, 0.0, 0.0)), Vec3::new(0.0, 10.0, 0.0)), "{:?}", place(&s, "Arm", Vec3::new(10.0, 0.0, 0.0)));
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}
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/// A loop that can't close does not hold up another one: the four-bar still drives beside a
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/// block whose rigid joint wants it where its pivot can't take it.
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#[test]
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fn a_broken_loop_does_not_stop_another() {
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let (mut s, _, q0) = four_bar();
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part(&mut s, "Block", [200.0, -1.0, -5.0]);
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pin(&mut s, "revolute", "Block pivot", "Ground", "Block", Vec3::new(200.0, 0.0, 0.0), Vec3::Z);
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run(
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&mut s,
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"joint.create",
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json!({"type": "rigid", "a": {"occurrence": "Ground", "point": [200, 0, 0]}, "b": {"occurrence": "Block", "point": [210, 0, 0]}, "flip": true, "name": "Wrong"}),
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);
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let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": 60}));
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let names: Vec<&str> = r["conflicts"].as_array().into_iter().flatten().filter_map(|c| c["name"].as_str()).collect();
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assert_eq!(names, ["Wrong"], "{r}");
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assert!(r["stopped_by_loop"].is_null(), "{r}");
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assert!(near(place(&s, "Rocker", q0), rocker_pin(0.0, 60.0, q0)), "{:?}", place(&s, "Rocker", q0));
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}
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/// A loop locked rigid can't move at all: driving its crank stops at once.
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#[test]
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fn a_locked_loop_does_not_move() {
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let (mut s, _, _) = four_bar();
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run(&mut s, "joint.as_built", json!({"type": "rigid", "a": "Ground", "b": "Rocker", "name": "Lock"}));
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let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": 360}));
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assert!(r["stopped_by_loop"].is_object(), "{r}");
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assert!(r["values"][0].as_f64().unwrap_or(f64::NAN).abs() < 1e-3, "{r}");
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}
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/// A link that turns the rocker 100 times as far as its dial: a small turn of the dial is a full
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/// turn of the rocker, which it can't make.
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#[test]
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fn a_geared_down_loop_value_is_followed_all_the_way() {
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let (mut s, _, _) = four_bar();
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part(&mut s, "Dial", [80.0, 0.0, -5.0]);
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pin(&mut s, "revolute", "Dial", "Ground", "Dial", Vec3::new(80.0, 0.0, 0.0), Vec3::Z);
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run(&mut s, "joint.motion_link", json!({"a": "Dial", "b": "Rocker", "ratio": 100}));
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let r = run(&mut s, "joint.drive", json!({"joint": "Dial", "value": 3.6}));
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assert!(r["stopped_by_loop"].is_object(), "{r}");
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assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
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}
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/// A suppressed dial still turns the rocker through its motion link, and a rocker whose value
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/// the file leaves out starts from 0: both are followed all the way, so a full turn stops.
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#[test]
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fn a_full_turn_stops_from_a_suppressed_dial_or_a_missing_value() {
|
||||
let (mut s, _, _) = four_bar();
|
||||
part(&mut s, "Dial", [80.0, 0.0, -5.0]);
|
||||
pin(&mut s, "revolute", "Dial", "Ground", "Dial", Vec3::new(80.0, 0.0, 0.0), Vec3::Z);
|
||||
run(&mut s, "joint.motion_link", json!({"a": "Dial", "b": "Rocker", "ratio": 0.5}));
|
||||
run(&mut s, "joint.edit", json!({"joint": "Dial", "suppressed": true}));
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "Dial", "value": 720}));
|
||||
assert!(r["stopped_by_loop"].is_object(), "{r}");
|
||||
// Undriven, the suppressed dial still follows the rocker when the crank turns.
|
||||
run(&mut s, "joint.drive", json!({"joint": "Dial", "value": 0}));
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": 60}));
|
||||
assert!(r["stopped_by_loop"].is_null() && r["conflicts"].as_array().map(Vec::len) == Some(0), "{r}");
|
||||
let (mut s, _, _) = four_bar();
|
||||
if let Some(j) = s.doc_mut().assembly.joints.iter_mut().find(|j| j.name == "Rocker") {
|
||||
j.values.clear();
|
||||
}
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "Rocker", "value": 360}));
|
||||
assert!(r["stopped_by_loop"].is_object(), "{r}");
|
||||
}
|
||||
|
||||
/// Loops that only share a rigid joint are independent: an arm whose lock can't close does not
|
||||
/// stop another arm, beside it on the same rigidly mounted base, from closing its own loop.
|
||||
#[test]
|
||||
fn loops_sharing_only_a_rigid_joint_are_solved_apart() {
|
||||
let mut s = Session::default();
|
||||
for (name, x) in [("Ground", -1.0), ("Base", -1.0), ("Arm", 0.0), ("Other", 100.0)] {
|
||||
part(&mut s, name, [x, -1.0, 0.0]);
|
||||
}
|
||||
let g = occ(&s, "Ground");
|
||||
run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
|
||||
run(&mut s, "joint.as_built", json!({"type": "rigid", "a": "Ground", "b": "Base", "name": "Mount"}));
|
||||
pin(&mut s, "revolute", "Pivot", "Base", "Arm", Vec3::ZERO, Vec3::Z);
|
||||
pin(&mut s, "revolute", "Other pivot", "Base", "Other", Vec3::new(100.0, 0.0, 0.0), Vec3::Z);
|
||||
run(
|
||||
&mut s,
|
||||
"joint.create",
|
||||
json!({"type": "rigid", "a": {"occurrence": "Ground", "point": [100, 0, 0]}, "b": {"occurrence": "Other", "point": [110, 0, 0]}, "flip": true, "name": "Wrong"}),
|
||||
);
|
||||
let r = run(
|
||||
&mut s,
|
||||
"joint.create",
|
||||
json!({"type": "rigid", "a": framed("Ground", [0.0; 3], [0.0, 0.0, 1.0], [0.0, 1.0, 0.0]),
|
||||
"b": framed("Arm", [0.0; 3], [0.0, 0.0, 1.0], [1.0, 0.0, 0.0]), "flip": true, "name": "Lock"}),
|
||||
);
|
||||
// The broken loop is reported (on whichever of its joints closes it), the arm's is not.
|
||||
let names: Vec<&str> = r["conflicts"].as_array().into_iter().flatten().filter_map(|c| c["name"].as_str()).collect();
|
||||
assert!(names.len() == 1 && ["Wrong", "Other pivot"].contains(&names[0]), "{r}");
|
||||
assert!(near(place(&s, "Arm", Vec3::new(10.0, 0.0, 0.0)), Vec3::new(0.0, 10.0, 0.0)), "{:?}", place(&s, "Arm", Vec3::new(10.0, 0.0, 0.0)));
|
||||
}
|
||||
|
||||
/// Two links writing one value: whichever carries a driven dial's turn into the loop, the turn
|
||||
/// is followed (here dial A turns gear B, which turns the rocker, before dial D rewrites B).
|
||||
#[test]
|
||||
fn a_turn_carried_in_by_any_link_is_followed() {
|
||||
let (mut s, _, _) = four_bar();
|
||||
for (name, x) in [("A", 80.0), ("B", 100.0), ("D", 120.0)] {
|
||||
part(&mut s, name, [x, 0.0, -5.0]);
|
||||
pin(&mut s, "revolute", name, "Ground", name, Vec3::new(x, 0.0, 0.0), Vec3::Z);
|
||||
}
|
||||
run(&mut s, "joint.motion_link", json!({"a": "A", "b": "B", "ratio": 1}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "B", "b": "Rocker", "ratio": 0.5}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "D", "b": "B", "ratio": 1}));
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "A", "value": 720}));
|
||||
assert!(r["stopped_by_loop"].is_object(), "{r}");
|
||||
}
|
||||
|
||||
/// Several links writing one value: every value a link chain starts from can move to close the
|
||||
/// loop, whichever of them the link order lets through (here dial A's, before dial B rewrites
|
||||
/// the gear).
|
||||
#[test]
|
||||
fn a_loop_value_moves_through_whichever_link_carries_it() {
|
||||
let (mut s, _, q0) = four_bar();
|
||||
for (name, x) in [("A", 80.0), ("G", 100.0), ("B", 120.0)] {
|
||||
part(&mut s, name, [x, 0.0, -5.0]);
|
||||
pin(&mut s, "revolute", name, "Ground", name, Vec3::new(x, 0.0, 0.0), Vec3::Z);
|
||||
}
|
||||
run(&mut s, "joint.motion_link", json!({"a": "A", "b": "G", "ratio": 1}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "G", "b": "Rocker", "ratio": 1}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "B", "b": "G", "ratio": 1}));
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "Crank", "value": 60}));
|
||||
assert!(r["stopped_by_loop"].is_null() && r["conflicts"].as_array().map(Vec::len) == Some(0), "{r}");
|
||||
assert!(near(place(&s, "Rocker", q0), rocker_pin(0.0, 60.0, q0)), "{:?}", place(&s, "Rocker", q0));
|
||||
}
|
||||
|
||||
/// Two values of one joint can feed two independent loops: a puck's x drives a pair of parallel
|
||||
/// slides, its y a slide whose rigid lock can't close. Driving x moves the healthy pair.
|
||||
#[test]
|
||||
fn values_of_one_joint_feed_independent_loops() {
|
||||
let mut s = Session::default();
|
||||
for (name, y) in [("Ground", -10.0), ("Puck", -20.0), ("Car", 50.0), ("Other", 100.0)] {
|
||||
part(&mut s, name, [-1.0, y, 0.0]);
|
||||
}
|
||||
let g = occ(&s, "Ground");
|
||||
run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
|
||||
let flat = |o: &str| framed(o, [0.0, -20.0, 0.0], [0.0, 0.0, 1.0], [1.0, 0.0, 0.0]);
|
||||
run(&mut s, "joint.create", json!({"type": "planar", "a": flat("Ground"), "b": flat("Puck"), "flip": true, "name": "Table"}));
|
||||
pin(&mut s, "slider", "Rail", "Ground", "Car", Vec3::new(0.0, 50.0, 0.0), Vec3::X);
|
||||
pin(&mut s, "slider", "Guide", "Ground", "Car", Vec3::new(10.0, 50.0, 0.0), Vec3::X);
|
||||
pin(&mut s, "slider", "Lift", "Ground", "Other", Vec3::new(0.0, 100.0, 0.0), Vec3::Y);
|
||||
run(
|
||||
&mut s,
|
||||
"joint.create",
|
||||
json!({"type": "rigid", "a": {"occurrence": "Ground", "point": [0, 100, 0]}, "b": {"occurrence": "Other", "point": [10, 100, 0]}, "flip": true, "name": "Wrong"}),
|
||||
);
|
||||
run(&mut s, "joint.motion_link", json!({"a": "Table", "ia": 0, "b": "Rail", "ratio": 1}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "Table", "ia": 1, "b": "Lift", "ratio": 1}));
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "Table", "values": [10]}));
|
||||
assert!(r["stopped_by_loop"].is_null(), "{r}");
|
||||
let names: Vec<&str> = r["conflicts"].as_array().into_iter().flatten().filter_map(|c| c["name"].as_str()).collect();
|
||||
assert_eq!(names, ["Wrong"], "{r}");
|
||||
assert!(near(place(&s, "Car", Vec3::new(0.0, 50.0, 0.0)), Vec3::new(10.0, 50.0, 0.0)), "{:?}", place(&s, "Car", Vec3::new(0.0, 50.0, 0.0)));
|
||||
}
|
||||
|
||||
/// Two loops can move different values of one joint: each keeps what it moved. A table's x
|
||||
/// feeds one pair of parallel slides and its y another; a study drives both pairs.
|
||||
#[test]
|
||||
fn loops_moving_different_values_of_one_joint_keep_both() {
|
||||
let mut s = Session::default();
|
||||
for (name, y) in [("Ground", -10.0), ("Puck", -20.0), ("CarA", 50.0), ("CarB", 100.0)] {
|
||||
part(&mut s, name, [-1.0, y, 0.0]);
|
||||
}
|
||||
let g = occ(&s, "Ground");
|
||||
run(&mut s, "occurrence.ground", json!({"occurrence": g, "grounded": true}));
|
||||
let flat = |o: &str| framed(o, [0.0, -20.0, 0.0], [0.0, 0.0, 1.0], [1.0, 0.0, 0.0]);
|
||||
run(&mut s, "joint.create", json!({"type": "planar", "a": flat("Ground"), "b": flat("Puck"), "flip": true, "name": "Table"}));
|
||||
for (car, y) in [("CarA", 50.0), ("CarB", 100.0)] {
|
||||
pin(&mut s, "slider", &format!("{car} rail"), "Ground", car, Vec3::new(0.0, y, 0.0), Vec3::X);
|
||||
pin(&mut s, "slider", &format!("{car} guide"), "Ground", car, Vec3::new(10.0, y, 0.0), Vec3::X);
|
||||
}
|
||||
run(&mut s, "joint.motion_link", json!({"a": "Table", "ia": 0, "b": "CarA rail", "ratio": 1}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "Table", "ia": 1, "b": "CarB rail", "ratio": 1}));
|
||||
let keys = json!([{"joint": "CarA guide", "points": [[0, 0], [10, 10]]}, {"joint": "CarB guide", "points": [[0, 0], [10, 20]]}]);
|
||||
run(&mut s, "motion.study", json!({"name": "Both", "steps": 10, "keys": keys}));
|
||||
let r = run(&mut s, "motion.play", json!({"study": "Both", "step": 10}));
|
||||
assert!(r["stopped_by_loop"].is_null(), "{r}");
|
||||
let table = s.doc.assembly.joints.iter().find(|j| j.name == "Table").map(|j| j.values.clone()).unwrap_or_default();
|
||||
assert!(table.len() == 3 && (table[0] - 10.0).abs() < 1e-6 && (table[1] - 20.0).abs() < 1e-6, "{table:?}");
|
||||
// A solve with nothing driven leaves them where they are.
|
||||
run(&mut s, "joint.solve", json!({}));
|
||||
assert!(near(place(&s, "CarA", Vec3::new(0.0, 50.0, 0.0)), Vec3::new(10.0, 50.0, 0.0)), "{:?}", place(&s, "CarA", Vec3::new(0.0, 50.0, 0.0)));
|
||||
assert!(near(place(&s, "CarB", Vec3::new(0.0, 100.0, 0.0)), Vec3::new(20.0, 100.0, 0.0)), "{:?}", place(&s, "CarB", Vec3::new(0.0, 100.0, 0.0)));
|
||||
}
|
||||
|
||||
/// A clamped link can jump: a 100:1 link to a rocker limited to a full turn reaches its limit
|
||||
/// after the dial's first few degrees, back where it started. Each step is checked, so the drive
|
||||
/// still stops where the rocker can't go.
|
||||
#[test]
|
||||
fn a_clamped_link_is_followed_step_by_step() {
|
||||
let (mut s, _, _) = four_bar();
|
||||
part(&mut s, "Dial", [80.0, 0.0, -5.0]);
|
||||
pin(&mut s, "revolute", "Dial", "Ground", "Dial", Vec3::new(80.0, 0.0, 0.0), Vec3::Z);
|
||||
run(&mut s, "joint.limits", json!({"joint": "Rocker", "min": 0, "max": 360}));
|
||||
run(&mut s, "joint.motion_link", json!({"a": "Dial", "b": "Rocker", "ratio": 100}));
|
||||
let r = run(&mut s, "joint.drive", json!({"joint": "Dial", "value": 360}));
|
||||
assert!(r["stopped_by_loop"].is_object(), "{r}");
|
||||
assert_eq!(r["conflicts"].as_array().map(Vec::len), Some(0), "{r}");
|
||||
}
|
||||
Reference in new issue
Block a user