| """Physics-informed GMAW/MIG-MAG robotic welding dataset teacher. |
| |
| Uses the shared 1–15 axis robot inverse-dynamics routine in robot_physics.rnea_tree |
| inverse-dynamics simulator. One torch per welding segment; additional arms may |
| move as fixtures/supports. No weld metallurgical quality/penetration prediction. |
| |
| Arc electric energy and thermal heat to workpiece are NOT additive. Gas is |
| volumetric consumption, not electrical energy. Synthetic and uncalibrated. |
| """ |
| from __future__ import annotations |
| import math |
| from dataclasses import dataclass |
| import numpy as np |
| from robot_physics import rnea_tree, quintic_trajectory, _rot, robot_configuration |
|
|
| PRIVATE_SOURCE_FIELDS = ('private_source_efficiency','private_wire_drive_scale','private_cooling_scale', |
| 'private_fume_scale','private_valve_scale') |
|
|
| DENSITY_G_MM3 = {'carbon_steel':.00785,'stainless':.0079,'aluminum':.00270} |
| WIRE_CHOICES = {'carbon_steel':('ER70S-6',.00785), 'stainless':('ER308LSi',.00790), 'aluminum':('ER4043',.00270)} |
|
|
| def machine_source(rng, ood=False): |
| return {'source_nominal_efficiency':.86,'source_nameplate_W':15000., |
| 'wire_feeder_nominal_W':55.,'cooling_nominal_W':210., |
| 'fume_extraction_nominal_W':260.,'gas_valve_nominal_W':9., |
| 'source_standby_nominal_W':68., |
| 'private_source_efficiency':float(rng.uniform(.71,.78) if ood else rng.uniform(.80,.92)), |
| 'private_wire_drive_scale':float(rng.uniform(1.25,1.55) if ood else rng.uniform(.78,1.24)), |
| 'private_cooling_scale':float(rng.uniform(1.18,1.48) if ood else rng.uniform(.75,1.20)), |
| 'private_fume_scale':float(rng.uniform(1.18,1.48) if ood else rng.uniform(.75,1.21)), |
| 'private_valve_scale':float(rng.uniform(.85,1.2))} |
|
|
| def public_source(source): |
| return {k:v for k,v in source.items() if k not in PRIVATE_SOURCE_FIELDS} |
|
|
| def fk_positions(cfg, q): |
| """Return link pivot and link orientation, in world coordinates.""" |
| n=cfg['n']; rotations=[None]*n; pivots=[None]*n |
| for i in range(n): |
| p=cfg['parents'][i] |
| R0=np.eye(3) if p<0 else rotations[p] |
| base=np.zeros(3) if p<0 else pivots[p] |
| pivots[i]=base+R0@np.asarray(cfg['offsets'][i],float) |
| rotations[i]=R0@_rot(np.asarray(cfg['axes'][i],float),float(q[i])) |
| return rotations,pivots |
|
|
| def torch_tips(cfg): |
| pa=set(x for x in cfg['parents'] if x>=0) |
| return [i for i in range(cfg['n']) if i not in pa] |
|
|
| def torch_trajectory(cfg, q_sequence, tip_idx): |
| positions=[] |
| for q in q_sequence: |
| rotations,pivots=fk_positions(cfg,q) |
| |
| distal=2.*np.asarray(cfg['coms'][tip_idx],float)+np.array([.07,0,.025]) |
| positions.append(pivots[tip_idx]+rotations[tip_idx]@distal) |
| return np.asarray(positions) |
|
|
| def duration_for_joint_motion(cfg, q0, q1, speed=0.8): |
| d=float(np.max(np.abs(np.asarray(q1)-np.asarray(q0)))) |
| return max(.25,1.875*d/max(cfg['qmax']*speed,1e-5), math.sqrt(5.78*d/max(cfg['amax']*speed,1e-5))) |
|
|
| def timed_robot_motion(cfg, q0, q1, T, payload_kg=1.2, steps=20): |
| """Use the shared joint-tree inverse-dynamics and drive-loss equations for the requested duration. |
| |
| Returns Wh split into robotic joint drive and shared controller; includes no |
| seam process electric power. Joints are assumed position-controlled along |
| smooth quintic interpolation. 20 samples resolve smooth joint dynamics, not |
| high-frequency welding arc fluctuations. |
| """ |
| assert T>0 |
| q0=np.asarray(q0,float);q1=np.asarray(q1,float);n=cfg['n'] |
| q,dq,ddq=quintic_trajectory(q0,q1,T,steps) |
| pa=np.asarray(cfg['parents'],np.int64) |
| offsets=np.asarray(cfg['offsets'],float);axes=np.asarray(cfg['axes'],float) |
| coms=np.asarray(cfg['coms'],float);mass=np.asarray(cfg['mass'],float).copy() |
| inertia=np.asarray(cfg['inertia'],float).copy() |
| ends=torch_tips(cfg) |
| for i in ends: |
| mass[i]+=payload_kg/len(ends) |
| inertia[i]+=payload_kg*.012/len(ends) |
| tau=np.array([rnea_tree(pa,offsets,axes,coms,mass,inertia,q[k],dq[k],ddq[k]) |
| for k in range(steps)]) |
| fric=(.12+.015*mass[None,:])*np.tanh(dq*18.)+.08*dq |
| actual=tau+fric*cfg['private_friction_scale'] |
| mechanical=actual*dq |
| efficiency=float(np.clip(cfg['motor_nominal_eff']*cfg['private_motor_efficiency'],.6,.98)) |
| copper=.020*actual**2*cfg['private_driver_loss'] |
| idle=(2.+.35*mass[None,:])*cfg['private_driver_loss'] |
| regen=cfg['regen_capability']*cfg['private_regen_scale'] |
| electric=np.maximum(mechanical,0)/efficiency+np.minimum(mechanical,0)*regen+copper+idle |
| bus=np.maximum(electric.sum(axis=1),0) |
| dt=T/(steps-1) |
| joints_Wh=float(np.trapezoid(bus,dx=dt)/3600) |
| controller_W=cfg['electronic_power_W']+16*n |
| controller_Wh=float(controller_W*T/3600) |
| |
| nom=tau+fric; nom_mech=nom*dq |
| nom_el=np.maximum(nom_mech,0)/cfg['motor_nominal_eff']+np.minimum(nom_mech,0)*cfg['regen_capability']+.020*nom**2+2.+.35*mass[None,:] |
| nom_joints=float(np.trapezoid(np.maximum(nom_el.sum(axis=1),0),dx=dt)/3600) |
| return {'robot_joint_drives_Wh':joints_Wh,'robot_controller_Wh':controller_Wh, |
| 'nominal_robot_joint_drives_Wh':nom_joints, |
| 'nominal_robot_controller_Wh':controller_Wh, |
| 'mechanical_positive_J':float(np.trapezoid(np.maximum(mechanical,0).sum(axis=1),dx=dt)), |
| 'mechanical_regen_J':float(np.trapezoid(np.maximum(-mechanical,0).sum(axis=1),dx=dt))} |
|
|
| def welding_setting(rng, material, thickness_mm): |
| |
| |
| dia=float(rng.choice([.8,1.0,1.2,1.6],p=[.16,.36,.37,.11])) |
| mode='short_circuit' if dia<=1.0 and thickness_mm<=5 else rng.choice(['short_circuit','spray'],p=[.25,.75]) |
| feed=float(rng.uniform(3.5,9.5)) |
| amps=float(np.clip(32.+18.*feed*(dia**1.85)+(15. if mode=='spray' else 0.),75.,315.)) |
| volts=float(np.clip(16.+.040*amps+rng.normal(0,.7)+(1.0 if mode=='spray' else 0.),18.,33.)) |
| gas_mix='argon_co2' if material!='aluminum' else 'argon' |
| flow=float(rng.uniform(11.,15.) if material=='aluminum' else rng.uniform(10.,16.)) |
| travel=float(rng.uniform(4.2,12.5)) |
| thermal_eff=float(rng.uniform(.76,.84)) |
| trans_eff=float(rng.uniform(.91,.98)) |
| return {'wire_diameter_mm':dia,'wire_feed_m_min':feed,'current_A':amps,'voltage_V':volts, |
| 'travel_speed_mm_s':travel,'gas_flow_L_min':flow,'gas_type':gas_mix, |
| 'arc_thermal_efficiency':thermal_eff,'transfer_efficiency':trans_eff, |
| 'transfer_mode':mode} |
|
|
| def historical_power_probes(cfg,source,rng): |
| """Measurements from six BEFORE-target test loads. No target program observation. |
| |
| Watt probes include welding source loads and robot nameplate-like idle survey. |
| Pair current with source observed grid W, allowing MCE to identify losses. |
| """ |
| result=[] |
| for amp in (0.,90.,130.,180.,230.,280.): |
| volts=(0 if amp==0 else 17.5+.037*amp) |
| src=((amp*volts)/source['private_source_efficiency'] if amp else 0) |
| cooling=source['cooling_nominal_W']*source['private_cooling_scale'] |
| standby=source['source_standby_nominal_W'] |
| feeder=(source['wire_feeder_nominal_W']*.7*source['private_wire_drive_scale'] if amp else 0) |
| p=src+cooling+standby+feeder |
| result.append(float(max(0,p*(1+rng.normal(0,.005))))) |
| return result |
|
|
| def _power_for_source(source,setting): |
| weld_W=setting['voltage_V']*setting['current_A']/source['private_source_efficiency'] |
| feeder_W=source['wire_feeder_nominal_W']*source['private_wire_drive_scale']*(.5+setting['wire_feed_m_min']/11.) |
| return weld_W,feeder_W |
|
|
| def simulate_weld(cfg, source, program, steps=12, trace=False): |
| """One robotic GMAW job, multiple seams. Segments own their arc state. |
| |
| `program`: {setting:..., segments:[{q0,q1,kind,tip_index,payload_kg,...}], |
| material, shielding_preflow_s, shielding_postflow_s, gap_s} |
| """ |
| setting=program['setting']; material=program['material']; rho=DENSITY_G_MM3[material] |
| components={key:0. for key in ('robot_joint_drives_Wh','robot_controller_Wh', |
| 'welding_source_Wh','wire_feeder_Wh','cooling_Wh','fume_extraction_Wh', |
| 'gas_valve_Wh','source_standby_Wh')} |
| nominal_energy=0.; total_s=0.;arc_s=0.;torch_length_mm=0. |
| wire_consumed_g=0.;wire_deposited_g=0.;wire_spatter_g=0.;arc_heat_kJ=0. |
| gas_open_s=0.;gas_consumed_L=0.;mech_pos_J=0.;mech_regen_J=0. |
| weld_source_W,wire_W=_power_for_source(source,setting) |
| coolant_W=source['cooling_nominal_W']*source['private_cooling_scale'] |
| fume_W=source['fume_extraction_nominal_W']*source['private_fume_scale'] |
| valve_W=source['gas_valve_nominal_W']*source['private_valve_scale'] |
| standby_W=source['source_standby_nominal_W'] |
| wire_area_mm2=math.pi*setting['wire_diameter_mm']**2/4. |
| segment_rows=[] |
| for si,seg in enumerate(program['segments']): |
| q0=np.asarray(seg['q0'],float);q1=np.asarray(seg['q1'],float) |
| qtraj,_,_=quintic_trajectory(q0,q1,1,steps) |
| tip=int(seg['tip_index']) |
| path=0.; |
| if seg['kind']=='arc': |
| tipxyz=torch_trajectory(cfg,qtraj,tip) |
| path=float(np.sum(np.linalg.norm(np.diff(tipxyz,axis=0),axis=1))*1000) |
| if path<8:raise ValueError('weld segment path too short (<8 mm)') |
| |
| T=path/setting['travel_speed_mm_s'] |
| else: |
| T=duration_for_joint_motion(cfg,q0,q1,seg.get('speed_factor',.72)) |
| robot=timed_robot_motion(cfg,q0,q1,T,seg.get('payload_kg',1.2),steps) |
| for key in ('robot_joint_drives_Wh','robot_controller_Wh'):components[key]+=robot[key] |
| nominal_energy+=robot['nominal_robot_joint_drives_Wh']+robot['nominal_robot_controller_Wh'] |
| mech_pos_J+=robot['mechanical_positive_J'];mech_regen_J+=robot['mechanical_regen_J'] |
| total_s+=T |
| |
| components['source_standby_Wh']+=standby_W*T/3600 |
| components['cooling_Wh']+=coolant_W*T/3600 |
| components['fume_extraction_Wh']+=fume_W*T/3600 |
| nominal_energy+=(standby_W+source['cooling_nominal_W']+source['fume_extraction_nominal_W'])*T/3600 |
| if seg['kind']=='arc': |
| arc_s+=T; torch_length_mm+=path |
| components['welding_source_Wh']+=weld_source_W*T/3600 |
| components['wire_feeder_Wh']+=wire_W*T/3600 |
| nominal_energy+=(setting['voltage_V']*setting['current_A']/source['source_nominal_efficiency']+source['wire_feeder_nominal_W']*(.5+setting['wire_feed_m_min']/11.))*T/3600 |
| feed_wire_mm=setting['wire_feed_m_min']*1000*T/60 |
| consumed=wire_area_mm2*feed_wire_mm*rho |
| wire_consumed_g+=consumed |
| wire_deposited_g+=consumed*setting['transfer_efficiency'] |
| wire_spatter_g+=consumed*(1-setting['transfer_efficiency']) |
| arc_heat_kJ+=setting['arc_thermal_efficiency']*setting['voltage_V']*setting['current_A']*T/1000 |
| segment_rows.append({'segment_index':si,'kind':seg['kind'],'duration_s':T,'torch_path_mm':path, |
| 'robot_energy_Wh':robot['robot_joint_drives_Wh']+robot['robot_controller_Wh']}) |
| |
| pre=float(program['shielding_preflow_s']);post=float(program['shielding_postflow_s']) |
| gas_open_s=arc_s+pre+post |
| gas_consumed_L=gas_open_s*setting['gas_flow_L_min']/60 |
| |
| idle_T=pre+post |
| hold_joint_W=sum((2+.35*float(m))*cfg['private_driver_loss'] for m in cfg['mass']) |
| hold_ctrl=cfg['electronic_power_W']+16*cfg['n'] |
| components['robot_joint_drives_Wh']+=hold_joint_W*idle_T/3600 |
| components['robot_controller_Wh']+=hold_ctrl*idle_T/3600 |
| components['source_standby_Wh']+=standby_W*idle_T/3600 |
| components['cooling_Wh']+=coolant_W*idle_T/3600 |
| components['fume_extraction_Wh']+=fume_W*idle_T/3600 |
| components['gas_valve_Wh']+=valve_W*gas_open_s/3600 |
| nominal_energy+=(hold_ctrl+sum((2+.35*float(m)) for m in cfg['mass'])+standby_W+source['cooling_nominal_W']+source['fume_extraction_nominal_W'])*idle_T/3600 |
| nominal_energy+=source['gas_valve_nominal_W']*gas_open_s/3600 |
| total_s+=idle_T |
| |
| cool_tail=float(program['cooling_tail_s']);total_s+=cool_tail |
| components['cooling_Wh']+=coolant_W*cool_tail/3600 |
| components['fume_extraction_Wh']+=fume_W*cool_tail/3600 |
| components['robot_controller_Wh']+=(cfg['electronic_power_W']+16*cfg['n'])*cool_tail/3600 |
| components['source_standby_Wh']+=standby_W*cool_tail/3600 |
| nominal_energy+=(source['cooling_nominal_W']+source['fume_extraction_nominal_W']+cfg['electronic_power_W']+16*cfg['n']+standby_W)*cool_tail/3600 |
| total_energy=float(sum(components.values())) |
| result={'time_s':float(total_s),'energy_Wh':total_energy,'nominal_energy_Wh':float(nominal_energy), |
| 'arc_on_s':float(arc_s),'arc_length_mm':float(torch_length_mm),'gas_on_s':float(gas_open_s), |
| 'gas_consumed_L':float(gas_consumed_L),'wire_consumed_g':float(wire_consumed_g), |
| 'wire_deposited_g':float(wire_deposited_g),'spatter_g':float(wire_spatter_g), |
| 'arc_energy_kJ':float(setting['current_A']*setting['voltage_V']*arc_s/1000), |
| 'heat_to_workpiece_kJ':float(arc_heat_kJ),'heat_input_kJ_mm':float(arc_heat_kJ/max(torch_length_mm,1e-9)), |
| 'material_removed_g':0.,'material_added_g':float(wire_deposited_g), |
| 'positive_mechanical_J':mech_pos_J,'regenerative_mechanical_J':mech_regen_J, |
| 'energy_components_Wh':components, |
| 'segment_summary':segment_rows} |
| return result |
|
|
