diff --git a/Marlin/src/module/planner.cpp b/Marlin/src/module/planner.cpp index 6d2a0edc31..ee357179c0 100644 --- a/Marlin/src/module/planner.cpp +++ b/Marlin/src/module/planner.cpp @@ -2306,87 +2306,87 @@ bool Planner::_populate_block(block_t * const block, bool split_move, vmax_junction_sqr = junction_acceleration * junction_deviation_mm * sin_theta_d2 / (1.0f - sin_theta_d2); - if (block->millimeters < 1) { - const float neg = junction_cos_theta < 0 ? -1 : 1, - t = neg * junction_cos_theta; + // For small moves with >135° junction (octagon) find speed for approximate arc + if (block->millimeters < 1 && junction_cos_theta < -0.7071067812f) { - // If angle is greater than 135 degrees (octagon), find speed for approximate arc - if (t > 0.7071067812f) { + #if ENABLED(JD_USE_MATH_ACOS) - #if ENABLED(JD_USE_MATH_ACOS) + #error "TODO: Inline maths with the MCU / FPU." - #error "TODO: Inline maths with the MCU / FPU." + #elif ENABLED(JD_USE_LOOKUP_TABLE) - #elif ENABLED(JD_USE_LOOKUP_TABLE) + // Fast acos approximation (max. error +-0.01 rads) + // Based on LUT table and linear interpolation - // Fast acos approximation (max. error +-0.01 rads) - // Based on LUT table and linear interpolation + /** + * // Generate the JD Lookup Table + * constexpr float c = 1.00751317f; // Correction factor to center error around 0 + * for (int i = 0; i < jd_lut_count - 1; ++i) { + * const float x0 = (sq(i) - 1) / sq(i), + * y0 = acos(x0) * (i ? c : 1), + * x1 = 0.5 * x0 + 0.5, + * y1 = acos(x1) * c; + * jd_lut_k[i] = (y0 - y1) / (x0 - x1); + * jd_lut_b[i] = (y1 * x0 - y0 * x1) / (x0 - x1); + * } + * jd_lut_k[jd_lut_count - 1] = jd_lut_b[jd_lut_count - 1] = 0; + * + * // Compute correction factor (Set c to 1.0f first!) + * float min = INFINITY, max = -min; + * for (float t = 0; t <= 1; t += 0.0003f) { + * const float e = acos(t) / approx(t); + * if (isfinite(e)) { + * if (e < min) min = e; + * if (e > max) max = e; + * } + * } + * fprintf(stderr, "%.9gf, ", (min + max) / 2); + */ + static constexpr int16_t jd_lut_count = 15; + static constexpr uint16_t jd_lut_tll = 1 << jd_lut_count; + static constexpr int16_t jd_lut_tll0 = __builtin_clz(jd_lut_tll) + 1; // i.e., 16 - jd_lut_count + static constexpr float jd_lut_k[jd_lut_count] PROGMEM = { + -1.03146219f, -1.30760407f, -1.75205469f, -2.41705418f, -3.37768555f, + -4.74888229f, -6.69648552f, -9.45659828f, -13.3640289f, -18.8927879f, + -26.7136307f, -37.7754059f, -53.4200745f, -75.5457306f, 0.0f }; + static constexpr float jd_lut_b[jd_lut_count] PROGMEM = { + 1.57079637f, 1.70886743f, 2.04220533f, 2.62408018f, 3.52467203f, + 4.85301876f, 6.77019119f, 9.50873947f, 13.4009094f, 18.9188652f, + 26.7320709f, 37.7884521f, 53.4292908f, 75.5522461f, 0.0f }; - /** - * // Generate the JD Lookup Table - * constexpr float c = 1.00751317f; // Correction factor to center error around 0 - * for (int i = 0; i < jd_lut_count - 1; ++i) { - * const float x0 = (sq(i) - 1) / sq(i), - * y0 = acos(x0) * (i ? c : 1), - * x1 = 0.5 * x0 + 0.5, - * y1 = acos(x1) * c; - * jd_lut_k[i] = (y0 - y1) / (x0 - x1); - * jd_lut_b[i] = (y1 * x0 - y0 * x1) / (x0 - x1); - * } - * jd_lut_k[jd_lut_count - 1] = jd_lut_b[jd_lut_count - 1] = 0; - * - * // Compute correction factor (Set c to 1.0f first!) - * float min = INFINITY, max = -min; - * for (float t = 0; t <= 1; t += 0.0003f) { - * const float e = acos(t) / approx(t); - * if (isfinite(e)) { - * if (e < min) min = e; - * if (e > max) max = e; - * } - * } - * fprintf(stderr, "%.9gf, ", (min + max) / 2); - */ - static constexpr int16_t jd_lut_count = 15; - static constexpr uint16_t jd_lut_tll = 1 << jd_lut_count; - static constexpr int16_t jd_lut_tll0 = __builtin_clz(jd_lut_tll) + 1; // i.e., 16 - jd_lut_count - static constexpr float jd_lut_k[jd_lut_count] PROGMEM = { - -1.03146219f, -1.30760407f, -1.75205469f, -2.41705418f, -3.37768555f, - -4.74888229f, -6.69648552f, -9.45659828f, -13.3640289f, -18.8927879f, - -26.7136307f, -37.7754059f, -53.4200745f, -75.5457306f, 0.0f }; - static constexpr float jd_lut_b[jd_lut_count] PROGMEM = { - 1.57079637f, 1.70886743f, 2.04220533f, 2.62408018f, 3.52467203f, - 4.85301876f, 6.77019119f, 9.50873947f, 13.4009094f, 18.9188652f, - 26.7320709f, 37.7884521f, 53.4292908f, 75.5522461f, 0.0f }; + const float neg = junction_cos_theta < 0 ? -1 : 1, + t = neg * junction_cos_theta; - const int16_t idx = (t == 0.0f) ? 0 : __builtin_clz(uint16_t((1.0f - t) * jd_lut_tll)) - jd_lut_tll0; + const int16_t idx = (t == 0.0f) ? 0 : __builtin_clz(uint16_t((1.0f - t) * jd_lut_tll)) - jd_lut_tll0; - float junction_theta = t * pgm_read_float(&jd_lut_k[idx]) + pgm_read_float(&jd_lut_b[idx]); - if (neg > 0) junction_theta = RADIANS(180) - junction_theta; + float junction_theta = t * pgm_read_float(&jd_lut_k[idx]) + pgm_read_float(&jd_lut_b[idx]); + if (neg > 0) junction_theta = RADIANS(180) - junction_theta; // acos(-t) - #else + #else - // Fast acos(-t) approximation (max. error +-0.033rad = 1.89°) - // Based on MinMax polynomial published by W. Randolph Franklin, see - // https://wrf.ecse.rpi.edu/Research/Short_Notes/arcsin/onlyelem.html - // acos( t) = pi / 2 - asin(x) - // acos(-t) = pi - acos(t) ... pi / 2 + asin(x) + // Fast acos(-t) approximation (max. error +-0.033rad = 1.89°) + // Based on MinMax polynomial published by W. Randolph Franklin, see + // https://wrf.ecse.rpi.edu/Research/Short_Notes/arcsin/onlyelem.html + // acos( t) = pi / 2 - asin(x) + // acos(-t) = pi - acos(t) ... pi / 2 + asin(x) - const float asinx = 0.032843707f - + t * (-1.451838349f - + t * ( 29.66153956f - + t * (-131.1123477f - + t * ( 262.8130562f - + t * (-242.7199627f - + t * ( 84.31466202f ) ))))), - junction_theta = RADIANS(90) + neg * asinx; // acos(-t) + const float neg = junction_cos_theta < 0 ? -1 : 1, + t = neg * junction_cos_theta, + asinx = 0.032843707f + + t * (-1.451838349f + + t * ( 29.66153956f + + t * (-131.1123477f + + t * ( 262.8130562f + + t * (-242.7199627f + + t * ( 84.31466202f ) ))))), + junction_theta = RADIANS(90) + neg * asinx; // acos(-t) - // NOTE: junction_theta bottoms out at 0.033 which avoids divide by 0. + // NOTE: junction_theta bottoms out at 0.033 which avoids divide by 0. - #endif + #endif - const float limit_sqr = (block->millimeters * junction_acceleration) / junction_theta; - NOMORE(vmax_junction_sqr, limit_sqr); - } + const float limit_sqr = (block->millimeters * junction_acceleration) / junction_theta; + NOMORE(vmax_junction_sqr, limit_sqr); } }