{
 "format": "protobytes-walking-studies-1",
 "prepared": "2026-09-30",
 "experimentDates": "2026-06-21 to 2026-06-23",
 "archive": "libPByte local development archive, mjx/ (MuJoCo MJX + JAX evolution on one NVIDIA A100, SMU SuperPOD)",
 "notes": [
  "Bodies were authored and fixed within each run; evolution acted on controller parameters only.",
  "Fitness definitions changed between studies, so fitness values are not comparable across studies.",
  "Forward distances are simulated meters within each study's trial length and settings; no cross-study ranking is implied.",
  "survival = fraction of the trial with the body up; meanLean_deg = mean fore-aft tilt of the root body.",
  "Most entries are single runs with one seed; no uncertainty estimates are available."
 ],
 "studies": [
  {
   "id": "quadruped",
   "body": "quad-abd: four legs, each with hip, knee, and lateral hip (abduction) joints",
   "source": "mjx/champion_abd.json",
   "sha256": "e26358165cc48ce5702ba66f05aa49b1dbab7988e5c83b1d7a360cad216c2fe9",
   "committed": "2026-06-21 (1fc0277)",
   "optimizer": "elitist genetic algorithm: best 32 retained, remaining population filled with Gaussian-mutated copies",
   "population": 128,
   "generations": 25,
   "trialSeconds": 6,
   "controller": "open-loop oscillator, 10 gait parameters (frequency; amplitude, center angle, phase lag for hip, knee, abduction); fixed crawl phase per leg",
   "fitness": "forward \u00d7 min(lowest torso height / standing height, 1) \u2212 0.2 \u00d7 |lateral drift|",
   "bestFitnessByGeneration": [
    1.791,
    1.802,
    1.802,
    2.488,
    2.488,
    2.988,
    2.988,
    2.988,
    2.988,
    3.134,
    3.134,
    3.134,
    3.152,
    3.33,
    3.33,
    3.748,
    3.748,
    4.136,
    4.136,
    4.136,
    4.136,
    4.136,
    4.136,
    4.136,
    4.136
   ],
   "champion": {
    "forward_m": 4.146,
    "lateral_m": 0.037,
    "lowestTorsoHeight_m": 0.58,
    "standingHeight_m": 0.58
   },
   "replay": {
    "source": "mjx/traj_abd.json",
    "sha256": "050905a0c3e381e6d25fb6512be51dd830cc49e5f0b971bee78bcadaa9a5a67b",
    "seconds": 7
   }
  },
  {
   "id": "hexapod",
   "body": "radial-6: six legs generated by radial reflection",
   "source": "mjx/grid6.json",
   "sha256": "3d723f7129d8419e59553a6df6892bda385c7b9964ca58d78195f089187d6bd0",
   "committed": "2026-06-21 (ddbf0d3)",
   "optimizer": "elitist genetic algorithm (truncation selection with Gaussian mutation)",
   "controller": "open-loop oscillator, 10 gait parameters plus one phase per leg, tripod-gait seed",
   "fitness": "forward \u00d7 uprightness \u2212 0.2 \u00d7 |lateral drift|",
   "trialSeconds": 5.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 1.738,
     "forward_m": 1.743
    },
    {
     "generation": 2,
     "fitness": 2.432,
     "forward_m": 2.484
    },
    {
     "generation": 4,
     "fitness": 3.031,
     "forward_m": 3.068
    },
    {
     "generation": 6,
     "fitness": 3.254,
     "forward_m": 3.377
    },
    {
     "generation": 8,
     "fitness": 3.351,
     "forward_m": 3.392
    },
    {
     "generation": 10,
     "fitness": 3.351,
     "forward_m": 3.392
    },
    {
     "generation": 12,
     "fitness": 3.369,
     "forward_m": 3.429
    },
    {
     "generation": 14,
     "fitness": 3.644,
     "forward_m": 3.722
    },
    {
     "generation": 15,
     "fitness": 3.738,
     "forward_m": 3.76
    },
    {
     "generation": 17,
     "fitness": 4.116,
     "forward_m": 4.328
    },
    {
     "generation": 19,
     "fitness": 4.116,
     "forward_m": 4.328
    },
    {
     "generation": 21,
     "fitness": 4.99,
     "forward_m": 5.228
    },
    {
     "generation": 23,
     "fitness": 4.99,
     "forward_m": 5.228
    },
    {
     "generation": 25,
     "fitness": 4.99,
     "forward_m": 5.228
    },
    {
     "generation": 27,
     "fitness": 4.99,
     "forward_m": 5.228
    },
    {
     "generation": 29,
     "fitness": 5.252,
     "forward_m": 5.257
    }
   ]
  },
  {
   "id": "octopod",
   "body": "radial-8: eight legs generated by radial reflection",
   "source": "mjx/grid8.json",
   "sha256": "24ab8622ee557b7c6f23e3174a4882b9950c52039d20f963d3d5682f8c2ecd44",
   "committed": "2026-06-21 (14cf2cc)",
   "optimizer": "elitist genetic algorithm (truncation selection with Gaussian mutation)",
   "controller": "as hexapod",
   "fitness": "as hexapod",
   "trialSeconds": 5.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 2.423,
     "forward_m": 2.535
    },
    {
     "generation": 2,
     "fitness": 3.633,
     "forward_m": 3.738
    },
    {
     "generation": 4,
     "fitness": 3.633,
     "forward_m": 3.738
    },
    {
     "generation": 6,
     "fitness": 3.633,
     "forward_m": 3.738
    },
    {
     "generation": 8,
     "fitness": 3.987,
     "forward_m": 4.256
    },
    {
     "generation": 10,
     "fitness": 4.516,
     "forward_m": 3.746
    },
    {
     "generation": 12,
     "fitness": 4.22,
     "forward_m": 4.024
    },
    {
     "generation": 14,
     "fitness": 4.918,
     "forward_m": 4.665
    },
    {
     "generation": 15,
     "fitness": 4.93,
     "forward_m": 4.915
    },
    {
     "generation": 17,
     "fitness": 5.29,
     "forward_m": 5.115
    },
    {
     "generation": 19,
     "fitness": 5.061,
     "forward_m": 5.115
    },
    {
     "generation": 21,
     "fitness": 5.453,
     "forward_m": 5.396
    },
    {
     "generation": 23,
     "fitness": 5.514,
     "forward_m": 5.396
    },
    {
     "generation": 25,
     "fitness": 6.377,
     "forward_m": 6.49
    },
    {
     "generation": 27,
     "fitness": 6.055,
     "forward_m": 6.49
    },
    {
     "generation": 29,
     "fitness": 5.502,
     "forward_m": 5.396
    }
   ],
   "note": "Checkpoint fitness values are not monotonic in this run, and the recorded replay distance can differ from the fitness logged during search. The longest recorded replay is generation 25 (6.49 m); the generation-29 replay travels 5.40 m."
  },
  {
   "id": "biped-armless",
   "body": "biped: two legs, heavy trunk on an actuated waist joint",
   "source": "mjx/gridBc.json",
   "sha256": "d2524cf94a14947587228c63da594bdfa4bbf3424249321b5802faa748f0d0b2",
   "committed": "2026-06-22 (823daed)",
   "optimizer": "elitist genetic algorithm (truncation selection with Gaussian mutation)",
   "controller": "oscillator rhythm plus a 4-neuron CTRNN sensing lean, lean rate, and height error",
   "fitness": "survival- and uprightness-gated forward distance with stride and foot-clearance terms",
   "trialSeconds": 6.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 0.503,
     "forward_m": 0.505,
     "survival": 1.0,
     "meanLean_deg": 2.3
    },
    {
     "generation": 26,
     "fitness": 0.675,
     "forward_m": 0.675,
     "survival": 0.976,
     "meanLean_deg": 10.6
    },
    {
     "generation": 53,
     "fitness": 0.748,
     "forward_m": 1.2,
     "survival": 0.879,
     "meanLean_deg": 17.8
    },
    {
     "generation": 79,
     "fitness": 0.848,
     "forward_m": 0.882,
     "survival": 0.991,
     "meanLean_deg": 8.9
    }
   ]
  },
  {
   "id": "biped-arms-only",
   "body": "biped with actuated arms; waist fixed",
   "source": "mjx/gridArmsOnly.json",
   "sha256": "8adb6736ea40d43831e68ec803f74795f41af46c47d9dada46ce8814c6b2ed25",
   "committed": "2026-06-22 (823daed)",
   "optimizer": "elitist genetic algorithm (truncation selection with Gaussian mutation)",
   "controller": "oscillator rhythm plus a 4-neuron CTRNN sensing lean, lean rate, and height error",
   "fitness": "survival- and uprightness-gated forward distance with stride and foot-clearance terms",
   "trialSeconds": 6.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 0.109,
     "forward_m": 0.106,
     "survival": 1.0,
     "meanLean_deg": 2.0
    },
    {
     "generation": 26,
     "fitness": 0.812,
     "forward_m": 0.881,
     "survival": 0.999,
     "meanLean_deg": 8.6
    },
    {
     "generation": 53,
     "fitness": 0.812,
     "forward_m": 0.881,
     "survival": 0.999,
     "meanLean_deg": 8.6
    },
    {
     "generation": 79,
     "fitness": 0.812,
     "forward_m": 0.881,
     "survival": 0.999,
     "meanLean_deg": 8.6
    }
   ]
  },
  {
   "id": "biped-arms",
   "body": "biped with actuated arms and waist",
   "source": "mjx/gridArms.json",
   "sha256": "ab5c327d68249e1bef1673b16159c25b29c5a414d2548004d24ff334b2697c77",
   "committed": "2026-06-22 (823daed)",
   "optimizer": "elitist genetic algorithm (truncation selection with Gaussian mutation)",
   "controller": "oscillator rhythm plus a 4-neuron CTRNN sensing lean, lean rate, and height error",
   "fitness": "survival- and uprightness-gated forward distance with stride and foot-clearance terms",
   "trialSeconds": 6.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 0.33,
     "forward_m": 0.325,
     "survival": 1.0,
     "meanLean_deg": 2.5
    },
    {
     "generation": 26,
     "fitness": 0.866,
     "forward_m": 0.889,
     "survival": 0.998,
     "meanLean_deg": 7.8
    },
    {
     "generation": 53,
     "fitness": 1.044,
     "forward_m": 1.031,
     "survival": 1.0,
     "meanLean_deg": 7.3
    },
    {
     "generation": 79,
     "fitness": 1.237,
     "forward_m": 1.474,
     "survival": 1.0,
     "meanLean_deg": 6.0
    }
   ]
  },
  {
   "id": "biped-tail",
   "body": "biped with a passive segmented tail (recursion operator)",
   "source": "mjx/gridTail.json",
   "sha256": "a4d123ce22198503c4d9e14613c2b3a0c1d2e41d4aa518fb68a8030e217acf1b",
   "committed": "2026-06-22 (823daed)",
   "optimizer": "elitist genetic algorithm (truncation selection with Gaussian mutation)",
   "controller": "oscillator rhythm plus a 4-neuron CTRNN sensing lean, lean rate, and height error",
   "fitness": "survival- and uprightness-gated forward distance with stride and foot-clearance terms",
   "trialSeconds": 6.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 0.001,
     "forward_m": 0.269,
     "survival": 0.464,
     "meanLean_deg": 18.3
    },
    {
     "generation": 26,
     "fitness": 0.437,
     "forward_m": 0.529,
     "survival": 1.0,
     "meanLean_deg": 12.6
    },
    {
     "generation": 53,
     "fitness": 0.781,
     "forward_m": 1.201,
     "survival": 1.0,
     "meanLean_deg": 20.0
    },
    {
     "generation": 79,
     "fitness": 0.781,
     "forward_m": 1.201,
     "survival": 1.0,
     "meanLean_deg": 20.0
    }
   ],
   "note": "Before the uprightness gate was added, this body scored 2.88 m by reclining about 73\u00b0 onto its tail (development log, commit 151c512/823daed). This file is the re-evolved result with the gate."
  },
  {
   "id": "humanoid-bent-knee",
   "body": "humanoid: 15 bodies, 11 actuated joints (spine, neck, head, shoulders, elbows, hips, knees)",
   "source": "mjx/gridHumanoidStep12.json",
   "sha256": "3f44d0b81ac529cdd6d133e613131812a8a5e8934cbb088c234813ad2668f7f4",
   "committed": "2026-06-23 (a83f131)",
   "optimizer": "CMA-ES with the best-so-far candidate re-inserted each generation",
   "controller": "oscillator rhythm plus an 8-neuron CTRNN with per-actuator outputs and foot-contact sensors",
   "fitness": "sublinear forward distance multiplied by foot alternation, knee flexion, arm counter-swing, heading and symmetry terms; upright and survival gates",
   "trialSeconds": 6.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": -0.0,
     "forward_m": -0.178,
     "survival": 0.035,
     "meanLean_deg": 100.4
    },
    {
     "generation": 31,
     "fitness": 0.0,
     "forward_m": 0.0,
     "survival": 0.0,
     "meanLean_deg": 100.7
    },
    {
     "generation": 63,
     "fitness": 0.0,
     "forward_m": 0.0,
     "survival": 0.0,
     "meanLean_deg": 100.7
    },
    {
     "generation": 94,
     "fitness": 0.0,
     "forward_m": 0.0,
     "survival": 0.0,
     "meanLean_deg": 100.7
    },
    {
     "generation": 125,
     "fitness": 0.0,
     "forward_m": 0.0,
     "survival": 0.0,
     "meanLean_deg": 100.7
    },
    {
     "generation": 156,
     "fitness": 0.009,
     "forward_m": 0.023,
     "survival": 1.0,
     "meanLean_deg": 10.1
    },
    {
     "generation": 188,
     "fitness": 0.044,
     "forward_m": 0.721,
     "survival": 1.0,
     "meanLean_deg": 2.0
    },
    {
     "generation": 219,
     "fitness": 0.044,
     "forward_m": 0.721,
     "survival": 1.0,
     "meanLean_deg": 2.0
    }
   ],
   "note": "Generation 0 falls (survival 0.035). Fitness values in this run are on a different scale from the other studies."
  },
  {
   "id": "humanoid-bilateral",
   "body": "humanoid with forward-flexing elbows",
   "source": "mjx/gridHumanoidBilat4.json",
   "sha256": "5b78a47335715da6ea8f89160257414ea1c3f1e6a2100b39d809ff7f87af951e",
   "committed": "2026-06-23 (6548271)",
   "optimizer": "CMA-ES with the best-so-far candidate re-inserted each generation",
   "controller": "oscillator rhythm plus an 8-neuron CTRNN run once per side with shared weights",
   "fitness": "as humanoid-bent-knee",
   "trialSeconds": 6.0,
   "checkpoints": [
    {
     "generation": 0,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 31,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 63,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 94,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 125,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 156,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 188,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    },
    {
     "generation": 219,
     "fitness": 0.063,
     "forward_m": 0.174,
     "survival": 1.0,
     "meanLean_deg": 7.4
    }
   ],
   "note": "Every checkpoint holds the same controller: the search did not improve on the seeded starting gait. The development log describes this form as correct but slow (about 0.1 m/s)."
  }
 ]
}