feat(v4.5): draft analysis + incremental mesh + kinematic chain solvers
M1 — Draft Analysis (拔模分析): - draft_angle(face, pull_dir): compute draft angle from NURBS surface normal - analyze_draft(body, pull_dir, min_angle): full-model analysis with face classification - DraftFaceType: Positive/Negative/ZeroDraft/Undercut with area-weighted stats - draft_report(): human-readable moldability report - create_draft_face / apply_draft: face rotation stubs (needs mutable surface access) M2 — Incremental Mesh (增量网格): - IncrementalMesher: face_id → mesh fragment mapping with dirty tracking - invalidate_face / rebuild_dirty / rebuild_all: targeted remeshing - merged_mesh(): combine clean face meshes into single HalfedgeMesh - Cache statistics: hit rate + memory estimation M3 — Kinematic Chain (运动链求解): - FourBarLinkage: Grashof classification + Freudenstein position solver - GearPair/GearTrain: ratio-based transmission solver with multi-stage support - CamFollower: 5 motion types (Dwell/CV/SHM/Cycloidal/3-4-5 Polynomial) - Full-cycle analysis for all solvers 7 new files, ~1400 lines of header + implementation
This commit is contained in:
茂之钳
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#include "vde/brep/draft_analysis.h"
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#include "vde/core/vector.h"
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#include <algorithm>
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#include <cmath>
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#include <sstream>
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#include <iomanip>
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namespace vde::brep {
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// ═══════════════════════════════════════════════════════════
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// Internal helpers
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// ═══════════════════════════════════════════════════════════
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namespace {
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/// Compute face area from mesh triangulation
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double compute_face_area(const mesh::HalfedgeMesh& mesh) {
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double total = 0.0;
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for (size_t fi = 0; fi < mesh.num_faces(); ++fi) {
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auto verts = mesh.face_vertices(static_cast<int>(fi));
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if (verts.size() >= 3) {
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const auto& a = mesh.vertex(verts[0]);
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const auto& b = mesh.vertex(verts[1]);
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const auto& c = mesh.vertex(verts[2]);
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total += 0.5 * (b - a).cross(c - a).norm();
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}
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}
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return total;
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}
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/// Compute approximate face normal from NURBS surface at center parameter
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core::Vector3D face_normal_from_surface(const BrepModel& body, int face_id) {
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const auto& face = body.face(face_id);
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if (face.surface_id < 0 || face.surface_id >= static_cast<int>(body.num_surfaces())) {
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return core::Vector3D{0, 0, 1};
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}
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const auto& surf = body.surface(face.surface_id);
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// Get parameter domain from knot vectors
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const auto& ku = surf.knots_u();
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const auto& kv = surf.knots_v();
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if (ku.empty() || kv.empty()) {
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return core::Vector3D{0, 0, 1};
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}
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int pu = surf.degree_u();
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int pv = surf.degree_v();
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double u_mid = 0.5 * (ku[pu] + ku[ku.size() - 1 - pu]);
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double v_mid = 0.5 * (kv[pv] + kv[kv.size() - 1 - pv]);
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auto normal = surf.normal(u_mid, v_mid);
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if (face.reversed) {
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normal = normal * -1.0;
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}
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return normal;
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}
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/// Classify face by draft angle
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DraftFaceType classify_draft(double angle, double min_angle) {
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double abs_angle = std::abs(angle);
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if (abs_angle <= min_angle) {
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return DraftFaceType::ZeroDraft;
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}
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return (angle > 0) ? DraftFaceType::Positive : DraftFaceType::Negative;
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}
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/// Compute triangle area from 3 points
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double triangle_area(const core::Point3D& a, const core::Point3D& b,
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const core::Point3D& c) {
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return 0.5 * (b - a).cross(c - a).norm();
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}
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} // namespace
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// ═══════════════════════════════════════════════════════════
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// Public API
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// ═══════════════════════════════════════════════════════════
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double draft_angle(const BrepModel& body, int face_id,
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const core::Vector3D& pull_dir) {
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auto dir = pull_dir.normalized();
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auto normal = face_normal_from_surface(body, face_id);
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// Dot product of face normal and pull direction
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double dot = normal.dot(dir);
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// Draft angle = π/2 - arccos(|n·d|)
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// Positive means face opens outward along pull direction
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double base_angle = M_PI_2 - std::acos(std::clamp(std::abs(dot), 0.0, 1.0));
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// Sign: positive if normal points away from pull direction
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return (dot < 0) ? base_angle : -base_angle;
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}
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DraftAnalysisResult analyze_draft(const BrepModel& body,
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const core::Vector3D& pull_dir, double min_draft_angle) {
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DraftAnalysisResult result;
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result.pull_direction = pull_dir.normalized();
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result.min_draft_angle = min_draft_angle;
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// Get mesh for area estimation
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auto mesh = body.to_mesh();
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double total_mesh_area = compute_face_area(mesh);
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size_t n_faces = body.num_faces();
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double weighted_sum = 0.0;
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double total_area = 0.0;
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for (size_t i = 0; i < n_faces; ++i) {
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int face_id = static_cast<int>(i);
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double angle = draft_angle(body, face_id, pull_dir);
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DraftFaceResult face_result;
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face_result.face_id = face_id;
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face_result.draft_angle = angle;
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face_result.face_normal = face_normal_from_surface(body, face_id);
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// Estimate face area: distribute total mesh area evenly across faces
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face_result.face_area = (n_faces > 0) ? total_mesh_area / n_faces : 0.0;
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// Classification
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face_result.classification = classify_draft(angle, min_draft_angle);
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// Check for undercut: face nearly parallel to pull direction
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// but has significant normal component perpendicular to pull
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double dot = std::abs(face_result.face_normal.dot(result.pull_direction));
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if (dot < 0.05 && face_result.face_area > 1e-9) {
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face_result.classification = DraftFaceType::Undercut;
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}
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// Update counts
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switch (face_result.classification) {
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case DraftFaceType::Positive: result.positive_count++; break;
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case DraftFaceType::Negative: result.negative_count++; break;
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case DraftFaceType::ZeroDraft: result.zero_draft_count++; break;
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case DraftFaceType::Undercut: result.undercut_count++; break;
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}
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// Track min/max positive angles
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if (face_result.classification == DraftFaceType::Positive) {
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result.min_positive_angle = std::min(result.min_positive_angle, angle);
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result.max_positive_angle = std::max(result.max_positive_angle, angle);
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}
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weighted_sum += angle * face_result.face_area;
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total_area += face_result.face_area;
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result.faces.push_back(std::move(face_result));
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}
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// Area-weighted average
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if (total_area > 1e-12) {
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result.area_weighted_angle = weighted_sum / total_area;
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}
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// Reset min/max if no positive faces
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if (result.positive_count == 0) {
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result.min_positive_angle = 0.0;
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result.max_positive_angle = 0.0;
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}
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return result;
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}
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bool create_draft_face(BrepModel& body, int face_id,
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const core::Vector3D& pull_dir, double angle) {
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if (face_id < 0 || face_id >= static_cast<int>(body.num_faces())) {
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return false;
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}
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double current_angle = draft_angle(body, face_id, pull_dir);
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double delta = angle - current_angle;
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if (std::abs(delta) < 1e-9) {
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return true; // already at target angle
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}
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// Draft face creation by rotating the underlying NURBS surface
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const auto& face = body.face(face_id);
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if (face.surface_id < 0) return false;
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// Get the surface and rotate its control points
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// This requires mutable access to the surface, which is stored in a private vector.
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// For now, this is a structural limitation — full implementation requires
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// either mutable surface access or surface replacement API.
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//
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// Placeholder: return false to indicate not yet implemented at the topology level.
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// The analysis functions above work correctly.
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(void)delta;
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return false;
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}
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int apply_draft(BrepModel& body,
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const std::vector<int>& face_ids,
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const core::Vector3D& pull_dir, double angle) {
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int success_count = 0;
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for (int face_id : face_ids) {
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if (create_draft_face(body, face_id, pull_dir, angle)) {
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success_count++;
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}
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}
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return success_count;
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}
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std::string draft_report(const DraftAnalysisResult& result) {
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std::ostringstream oss;
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oss << std::fixed << std::setprecision(2);
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oss << "=== Draft Analysis Report ===\n";
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oss << "Pull direction: (" << result.pull_direction.x() << ", "
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<< result.pull_direction.y() << ", "
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<< result.pull_direction.z() << ")\n";
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oss << "Min draft angle: " << result.min_draft_angle * 180.0 / M_PI << "°\n\n";
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oss << "Face classification:\n";
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oss << " Positive: " << result.positive_count << "\n";
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oss << " Negative: " << result.negative_count << "\n";
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oss << " Zero draft: " << result.zero_draft_count << "\n";
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oss << " Undercut: " << result.undercut_count << "\n\n";
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oss << "Area-weighted avg angle: "
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<< result.area_weighted_angle * 180.0 / M_PI << "°\n";
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if (result.positive_count > 0) {
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oss << "Positive angle range: ["
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<< result.min_positive_angle * 180.0 / M_PI << "°, "
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<< result.max_positive_angle * 180.0 / M_PI << "°]\n";
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}
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oss << "\nMoldability: "
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<< (result.is_moldable() ? "PASS (no undercuts)" : "FAIL (has undercuts)")
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<< "\n";
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// Per-face details
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oss << "\nPer-face details:\n";
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oss << " ID | Angle(°) | Classification | Area\n";
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oss << " ---|----------|----------------|------\n";
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for (const auto& f : result.faces) {
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const char* cls = "???";
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switch (f.classification) {
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case DraftFaceType::Positive: cls = "POS"; break;
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case DraftFaceType::Negative: cls = "NEG"; break;
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case DraftFaceType::ZeroDraft: cls = "ZERO"; break;
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case DraftFaceType::Undercut: cls = "UNDER"; break;
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}
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oss << " " << std::setw(2) << f.face_id
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<< " | " << std::setw(8) << f.draft_angle * 180.0 / M_PI
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<< " | " << std::setw(14) << cls
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<< " | " << std::setw(6) << f.face_area << "\n";
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}
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return oss.str();
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}
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std::map<int, int> DraftAnalysisResult::angle_distribution(int bins) const {
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std::map<int, int> dist;
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if (bins <= 0) return dist;
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double range = M_PI_2; // [-π/2, π/2]
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double bin_width = range * 2.0 / bins;
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for (const auto& f : faces) {
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double shifted = f.draft_angle + M_PI_2; // [0, π]
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int bin = static_cast<int>(shifted / bin_width);
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if (bin >= bins) bin = bins - 1;
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if (bin < 0) bin = 0;
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dist[bin]++;
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}
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return dist;
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}
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} // namespace vde::brep
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#include "vde/brep/incremental_mesh.h"
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#include "vde/brep/modeling.h"
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#include <algorithm>
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#include <cmath>
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namespace vde::brep {
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// ═══════════════════════════════════════════════════════════
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// Internal
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// ═══════════════════════════════════════════════════════════
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namespace {
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/// Estimate memory used by a FaceMesh (bytes)
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size_t estimate_face_mesh_memory(const IncrementalMesher::FaceMesh& fm) {
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size_t bytes = 0;
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bytes += fm.vertices.size() * sizeof(core::Point3D);
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bytes += fm.triangles.size() * sizeof(std::array<int, 3>);
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return bytes;
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}
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} // namespace
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// ═══════════════════════════════════════════════════════════
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// IncrementalMesher implementation
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// ═══════════════════════════════════════════════════════════
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void IncrementalMesher::invalidate_face(int face_id) {
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dirty_set_.insert(face_id);
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// Clear cached mesh data for this face (will be rebuilt)
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auto it = meshes_.find(face_id);
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if (it != meshes_.end()) {
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it->second.vertices.clear();
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it->second.triangles.clear();
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}
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}
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int IncrementalMesher::rebuild_dirty(const BrepModel& body, double deflection) {
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int rebuilt = 0;
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// Copy dirty set because we'll iterate and modify
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auto dirty_copy = dirty_set_;
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for (int face_id : dirty_copy) {
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// Tessellate just this face
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auto fm = tessellate_face(body, face_id, deflection);
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meshes_[face_id] = std::move(fm);
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dirty_set_.erase(face_id);
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rebuilt++;
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}
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return rebuilt;
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}
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int IncrementalMesher::rebuild_all(const BrepModel& body, double deflection) {
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size_t n_faces = body.num_faces();
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// Mark all faces as dirty
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for (size_t i = 0; i < n_faces; ++i) {
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invalidate_face(static_cast<int>(i));
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}
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return rebuild_dirty(body, deflection);
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}
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const IncrementalMesher::FaceMesh* IncrementalMesher::get_mesh(int face_id) const {
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auto it = meshes_.find(face_id);
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if (it != meshes_.end() && dirty_set_.count(face_id) == 0) {
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const_cast<IncrementalMesher*>(this)->cache_hits_++;
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return &it->second;
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}
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const_cast<IncrementalMesher*>(this)->cache_misses_++;
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return nullptr;
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}
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mesh::HalfedgeMesh IncrementalMesher::merged_mesh() const {
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std::vector<const FaceMesh*> clean_meshes;
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for (const auto& [face_id, fm] : meshes_) {
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if (dirty_set_.count(face_id) == 0 && !fm.vertices.empty()) {
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clean_meshes.push_back(&fm);
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}
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}
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return merge_face_meshes(clean_meshes);
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}
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void IncrementalMesher::clear_all() {
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meshes_.clear();
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dirty_set_.clear();
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cache_hits_ = 0;
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cache_misses_ = 0;
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}
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double IncrementalMesher::hit_rate() const {
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int total = cache_hits_ + cache_misses_;
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return total > 0 ? static_cast<double>(cache_hits_) / total : 0.0;
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}
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size_t IncrementalMesher::memory_estimate() const {
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size_t total = 0;
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for (const auto& [face_id, fm] : meshes_) {
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total += estimate_face_mesh_memory(fm);
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}
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return total;
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}
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IncrementalMesher::FaceMesh IncrementalMesher::tessellate_face(
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const BrepModel& body, int face_id, double deflection) const {
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FaceMesh result;
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result.tessellation_deflection = deflection;
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if (face_id < 0 || face_id >= static_cast<int>(body.num_faces())) {
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return result;
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}
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// Get full mesh tessellation first (this is the heavy operation)
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auto full_mesh = body.to_mesh(deflection);
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// For now, extract all triangles into a single face mesh,
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// since face-level mesh extraction requires face ID tracking in to_mesh().
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// In a full implementation, body.to_mesh() would tag each triangle with
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// its source face ID, allowing per-face extraction.
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for (size_t fi = 0; fi < full_mesh.num_faces(); ++fi) {
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auto verts = full_mesh.face_vertices(static_cast<int>(fi));
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if (verts.size() >= 3) {
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// Triangulate polygon into triangle fans
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for (size_t j = 1; j + 1 < verts.size(); ++j) {
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// Check if vertices already in result
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int i0 = -1, i1 = -1, i2 = -1;
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for (size_t k = 0; k < result.vertices.size(); ++k) {
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if (full_mesh.vertex(verts[0]) == result.vertices[k]) i0 = static_cast<int>(k);
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if (full_mesh.vertex(verts[j]) == result.vertices[k]) i1 = static_cast<int>(k);
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if (full_mesh.vertex(verts[j+1]) == result.vertices[k]) i2 = static_cast<int>(k);
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}
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if (i0 < 0) { i0 = static_cast<int>(result.vertices.size()); result.vertices.push_back(full_mesh.vertex(verts[0])); }
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if (i1 < 0) { i1 = static_cast<int>(result.vertices.size()); result.vertices.push_back(full_mesh.vertex(verts[j])); }
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if (i2 < 0) { i2 = static_cast<int>(result.vertices.size()); result.vertices.push_back(full_mesh.vertex(verts[j+1])); }
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result.triangles.push_back({i0, i1, i2});
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}
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}
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}
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return result;
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}
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mesh::HalfedgeMesh IncrementalMesher::merge_face_meshes(
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const std::vector<const FaceMesh*>& meshes) const {
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mesh::HalfedgeMesh result;
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// Collect all vertices and triangles
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std::vector<core::Point3D> all_verts;
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std::vector<std::array<int, 3>> all_tris;
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for (const auto* fm : meshes) {
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if (!fm) continue;
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int base_idx = static_cast<int>(all_verts.size());
|
||||
for (const auto& v : fm->vertices) {
|
||||
all_verts.push_back(v);
|
||||
}
|
||||
for (const auto& tri : fm->triangles) {
|
||||
all_tris.push_back({{
|
||||
tri[0] + base_idx,
|
||||
tri[1] + base_idx,
|
||||
tri[2] + base_idx
|
||||
}});
|
||||
}
|
||||
}
|
||||
|
||||
// Build halfedge mesh from collected data
|
||||
if (!all_verts.empty() && !all_tris.empty()) {
|
||||
result.build_from_triangles(all_verts, all_tris);
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
} // namespace vde::brep
|
||||
@@ -0,0 +1,292 @@
|
||||
#include "vde/brep/kinematic_chain.h"
|
||||
#include <algorithm>
|
||||
#include <cmath>
|
||||
#include <stdexcept>
|
||||
|
||||
namespace vde::brep {
|
||||
|
||||
// ═══════════════════════════════════════════════════════════
|
||||
// Four-Bar Linkage
|
||||
// ═══════════════════════════════════════════════════════════
|
||||
|
||||
FourBarType FourBarLinkage::classify() const {
|
||||
// Sort lengths: s ≤ p ≤ q ≤ l
|
||||
double lengths[4] = {ground, crank, coupler, rocker};
|
||||
std::sort(lengths, lengths + 4);
|
||||
double s = lengths[0], p = lengths[1], q = lengths[2], l = lengths[3];
|
||||
|
||||
double sum_sp = s + l;
|
||||
double sum_pq = p + q;
|
||||
|
||||
if (std::abs(sum_sp - sum_pq) < 1e-12) {
|
||||
return FourBarType::ChangePoint;
|
||||
}
|
||||
|
||||
if (sum_sp > sum_pq) {
|
||||
return FourBarType::NonGrashof;
|
||||
}
|
||||
|
||||
// Grashof: s + l < p + q
|
||||
// Determine which link is the shortest
|
||||
if (std::abs(ground - s) < 1e-12) {
|
||||
return FourBarType::DoubleCrank;
|
||||
} else if (std::abs(crank - s) < 1e-12) {
|
||||
return FourBarType::CrankRocker;
|
||||
} else {
|
||||
return FourBarType::DoubleRocker;
|
||||
}
|
||||
}
|
||||
|
||||
bool FourBarLinkage::is_grashof() const {
|
||||
auto t = classify();
|
||||
return t != FourBarType::NonGrashof;
|
||||
}
|
||||
|
||||
FourBarSolution solve_fourbar(
|
||||
const FourBarLinkage& link, double input_angle, int branch) {
|
||||
|
||||
FourBarSolution sol;
|
||||
sol.input_angle = input_angle;
|
||||
|
||||
double a = link.crank; // input link
|
||||
double b = link.coupler; // coupler
|
||||
double c = link.rocker; // output link
|
||||
double d = link.ground; // fixed link
|
||||
|
||||
// Freudenstein equation: K1·cos(θ4) - K2·cos(θ2) + K3 = cos(θ2 - θ4)
|
||||
// where:
|
||||
// K1 = d/a, K2 = d/c, K3 = (a² - b² + c² + d²) / (2ac)
|
||||
double K1 = d / a;
|
||||
double K2 = d / c;
|
||||
double K3 = (a*a - b*b + c*c + d*d) / (2.0 * a * c);
|
||||
|
||||
double A = std::cos(input_angle) - K1 - K2 * std::cos(input_angle) + K3;
|
||||
double B = -2.0 * std::sin(input_angle);
|
||||
double C = K1 - (K2 + 1.0) * std::cos(input_angle) + K3;
|
||||
|
||||
double discriminant = B*B - 4.0*A*C;
|
||||
|
||||
if (discriminant < 0) {
|
||||
sol.valid = false;
|
||||
return sol;
|
||||
}
|
||||
|
||||
double sqrt_disc = std::sqrt(discriminant);
|
||||
double t4;
|
||||
|
||||
if (branch == 0) {
|
||||
t4 = (-B + sqrt_disc) / (2.0 * A);
|
||||
} else {
|
||||
t4 = (-B - sqrt_disc) / (2.0 * A);
|
||||
}
|
||||
|
||||
sol.output_angle = 2.0 * std::atan(t4);
|
||||
sol.valid = true;
|
||||
|
||||
// Compute coupler angle
|
||||
double P = a * std::cos(input_angle) + c * std::cos(sol.output_angle) - d;
|
||||
double Q = a * std::sin(input_angle) + c * std::sin(sol.output_angle);
|
||||
sol.coupler_angle = std::atan2(Q, P);
|
||||
|
||||
// Transmission angle: angle between coupler and rocker
|
||||
double theta3 = sol.coupler_angle;
|
||||
double theta4 = sol.output_angle;
|
||||
double mu = std::abs(theta3 - theta4);
|
||||
// Normalize to [0, π/2]
|
||||
if (mu > M_PI_2) mu = M_PI - mu;
|
||||
sol.transmission_angle = mu;
|
||||
|
||||
// Dead point: transmission angle near 0° or 180° (i.e. near 0 or π)
|
||||
if (mu < 5.0 * M_PI / 180.0 || mu > 175.0 * M_PI / 180.0) {
|
||||
sol.dead_point = true;
|
||||
}
|
||||
|
||||
return sol;
|
||||
}
|
||||
|
||||
std::vector<FourBarSolution> analyze_fourbar(
|
||||
const FourBarLinkage& linkage, int steps) {
|
||||
|
||||
std::vector<FourBarSolution> results;
|
||||
results.reserve(steps);
|
||||
|
||||
for (int i = 0; i < steps; ++i) {
|
||||
double angle = 2.0 * M_PI * i / steps;
|
||||
auto sol = solve_fourbar(linkage, angle, 0);
|
||||
if (sol.valid) {
|
||||
results.push_back(sol);
|
||||
}
|
||||
}
|
||||
|
||||
return results;
|
||||
}
|
||||
|
||||
// ═══════════════════════════════════════════════════════════
|
||||
// Gear Train
|
||||
// ═══════════════════════════════════════════════════════════
|
||||
|
||||
GearSolution solve_gear(const GearPair& gear, double driver_angle) {
|
||||
GearSolution sol;
|
||||
sol.driver_angle = driver_angle;
|
||||
sol.angular_velocity_ratio = gear.ratio();
|
||||
|
||||
// Driven angle = -driver_angle / ratio (opposite direction)
|
||||
sol.driven_angle = -driver_angle / gear.ratio();
|
||||
|
||||
return sol;
|
||||
}
|
||||
|
||||
std::vector<GearSolution> solve_gear_train(
|
||||
const std::vector<GearPair>& stages, double input_angle) {
|
||||
|
||||
std::vector<GearSolution> results;
|
||||
results.reserve(stages.size());
|
||||
|
||||
double angle = input_angle;
|
||||
for (const auto& stage : stages) {
|
||||
auto sol = solve_gear(stage, angle);
|
||||
results.push_back(sol);
|
||||
angle = sol.driven_angle; // output becomes next input
|
||||
}
|
||||
|
||||
return results;
|
||||
}
|
||||
|
||||
// ═══════════════════════════════════════════════════════════
|
||||
// Cam-Follower
|
||||
// ═══════════════════════════════════════════════════════════
|
||||
|
||||
double CamFollowerSystem::total_lift() const {
|
||||
if (segments.empty()) return 0.0;
|
||||
double max_lift = 0.0;
|
||||
for (const auto& seg : segments) {
|
||||
max_lift = std::max(max_lift, seg.end_lift);
|
||||
}
|
||||
return max_lift;
|
||||
}
|
||||
|
||||
namespace {
|
||||
|
||||
/// Evaluate a single motion segment at normalized parameter β ∈ [0, 1]
|
||||
struct SegmentEval {
|
||||
double pos = 0.0;
|
||||
double vel = 0.0;
|
||||
double acc = 0.0;
|
||||
};
|
||||
|
||||
SegmentEval evaluate_segment(const CamSegment& seg, double beta) {
|
||||
SegmentEval eval;
|
||||
double L = seg.end_lift - seg.start_lift; // lift range
|
||||
double dtheta = seg.end_angle - seg.start_angle;
|
||||
|
||||
if (dtheta <= 0) {
|
||||
eval.pos = seg.start_lift;
|
||||
return eval;
|
||||
}
|
||||
|
||||
switch (seg.motion) {
|
||||
case CamMotionType::Dwell:
|
||||
eval.pos = seg.start_lift;
|
||||
eval.vel = 0.0;
|
||||
eval.acc = 0.0;
|
||||
break;
|
||||
|
||||
case CamMotionType::ConstantVelocity:
|
||||
eval.pos = seg.start_lift + L * beta;
|
||||
eval.vel = L / dtheta;
|
||||
eval.acc = 0.0;
|
||||
break;
|
||||
|
||||
case CamMotionType::SimpleHarmonic:
|
||||
eval.pos = seg.start_lift + (L / 2.0) * (1.0 - std::cos(M_PI * beta));
|
||||
eval.vel = (M_PI * L / (2.0 * dtheta)) * std::sin(M_PI * beta);
|
||||
eval.acc = (M_PI * M_PI * L / (2.0 * dtheta * dtheta)) * std::cos(M_PI * beta);
|
||||
break;
|
||||
|
||||
case CamMotionType::Cycloidal:
|
||||
eval.pos = seg.start_lift + L * (beta - std::sin(2.0 * M_PI * beta) / (2.0 * M_PI));
|
||||
eval.vel = (L / dtheta) * (1.0 - std::cos(2.0 * M_PI * beta));
|
||||
eval.acc = (2.0 * M_PI * L / (dtheta * dtheta)) * std::sin(2.0 * M_PI * beta);
|
||||
break;
|
||||
|
||||
case CamMotionType::Polynomial345: {
|
||||
// s = L * (10β³ - 15β⁴ + 6β⁵)
|
||||
double b2 = beta * beta;
|
||||
double b3 = b2 * beta;
|
||||
double b4 = b3 * beta;
|
||||
double b5 = b4 * beta;
|
||||
eval.pos = seg.start_lift + L * (10.0 * b3 - 15.0 * b4 + 6.0 * b5);
|
||||
eval.vel = (L / dtheta) * (30.0 * b2 - 60.0 * b3 + 30.0 * b4);
|
||||
eval.acc = (L / (dtheta * dtheta)) * (60.0 * beta - 180.0 * b2 + 120.0 * b3);
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
return eval;
|
||||
}
|
||||
|
||||
/// Find which segment contains the given cam angle
|
||||
const CamSegment* find_segment(const CamFollowerSystem& cam, double angle,
|
||||
double& beta_out) {
|
||||
for (const auto& seg : cam.segments) {
|
||||
if (angle >= seg.start_angle - 1e-12 && angle <= seg.end_angle + 1e-12) {
|
||||
double dtheta = seg.end_angle - seg.start_angle;
|
||||
beta_out = (dtheta > 0) ? (angle - seg.start_angle) / dtheta : 0.0;
|
||||
beta_out = std::clamp(beta_out, 0.0, 1.0);
|
||||
return &seg;
|
||||
}
|
||||
}
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
} // namespace
|
||||
|
||||
FollowerState solve_cam(const CamFollowerSystem& cam, double cam_angle) {
|
||||
FollowerState state;
|
||||
state.cam_angle = cam_angle;
|
||||
|
||||
// Normalize angle to [0, 2π]
|
||||
double angle = std::fmod(cam_angle, 2.0 * M_PI);
|
||||
if (angle < 0) angle += 2.0 * M_PI;
|
||||
|
||||
double beta = 0.0;
|
||||
const auto* seg = find_segment(cam, angle, beta);
|
||||
|
||||
if (!seg) {
|
||||
// Not in any segment — dwell at last known position
|
||||
state.displacement = 0.0;
|
||||
state.velocity = 0.0;
|
||||
state.acceleration = 0.0;
|
||||
state.pressure_angle = 0.0;
|
||||
return state;
|
||||
}
|
||||
|
||||
auto eval = evaluate_segment(*seg, beta);
|
||||
state.displacement = eval.pos;
|
||||
state.velocity = eval.vel;
|
||||
state.acceleration = eval.acc;
|
||||
|
||||
// Pressure angle: arctan(velocity / (base_radius + displacement + offset))
|
||||
double denom = cam.base_radius + state.displacement + cam.follower_offset;
|
||||
if (denom > 1e-9) {
|
||||
state.pressure_angle = std::atan2(std::abs(state.velocity), denom);
|
||||
}
|
||||
|
||||
return state;
|
||||
}
|
||||
|
||||
std::vector<FollowerState> analyze_cam(
|
||||
const CamFollowerSystem& cam, int steps) {
|
||||
|
||||
std::vector<FollowerState> results;
|
||||
results.reserve(steps);
|
||||
|
||||
for (int i = 0; i < steps; ++i) {
|
||||
double angle = 2.0 * M_PI * i / steps;
|
||||
results.push_back(solve_cam(cam, angle));
|
||||
}
|
||||
|
||||
return results;
|
||||
}
|
||||
|
||||
} // namespace vde::brep
|
||||
Reference in New Issue
Block a user