| name | collaborative-robot |
| description | Collaborative robot (cobot) — ISO/TS 15066 safety modes (SSM/PFL/HGP/SLS), TCP force/torque limits, power and force limiting (PFL), workspace design, UR/Fanuc/KUKA cobot specs. |
| metadata | {"priority":7,"promptSignals":{"phrases":["collaborative robot","cobot","ISO 15066","power force limiting","human robot collaboration","cobot safety","UR robot"],"minScore":3}} |
Collaborative Robot — Complete Skill
Standards Framework
ISO 10218-1/2 (2011): industrial robots and robot systems — general safety
ISO/TS 15066 (2016): robots and robotic devices — collaborative robots (supersedes TS 15066:2011)
ISO 10218 revision (2022): merged and expanded coverage
OSHA applicable: 29 CFR 1910.217 (power presses); 1910 Subpart O for industrial robots
ANSI/RIA R15.06: US national adoption of ISO 10218
Four Collaborative Operating Modes (ISO/TS 15066)
1. Safety-Rated Monitored Stop (SMS)
Robot stops when human enters workspace; resumes when human leaves
No force/power limits required (robot is stationary during collaboration)
Uses safety-rated (Category 3/PLd) stop function
Response time: < 0.2 s typical
2. Hand Guiding (HGP)
Human directly guides robot with force input at TCP (teach mode)
Speed limited: ≤ 250 mm/s (robot speed)
Force limiting not required if robot is speed-limited and compliance device used
End-effector must have force/torque sensor or gravity compensation
3. Speed and Separation Monitoring (SSM)
Robot operates at reduced speed based on distance to human
d_s = (v_r + v_h) × T_r + S_tr + Z_d + C
d_s = safety distance [m]
v_r = robot speed [m/s]; v_h = max human hand speed [1.6 m/s per ISO]
T_r = robot stopping time [s]
S_tr = position uncertainty; Z_d = detection zone uncertainty; C = intrusion depth
Safety scanner (SICK, Pepperl+Fuchs) measures human position → feeds PLC → speed scaling
4. Power and Force Limiting (PFL)
Robot continues operation; limits applied force so contact is non-injurious
Primary contact limit: from biomechanical injury data (ISO/TS 15066 Annex A, Tables A.2 and A.3)
Force and pressure limits per body region:
| Body Region | Max Force F [N] | Max Pressure P [N/cm²] |
|---|
| Skull/forehead | 130 | 49 |
| Face | 65 | 11 |
| Neck (front) | 145 | 7.8 |
| Chest | 210 | 25 |
| Hand/fingers | 140 | 30 |
| Lower arm | 160 | 36 |
| Upper arm | 150 | 32 |
| Thigh | 220 | 50 |
Quasi-static (clamping) limits: lower than transient; sustained contact more injurious
Transient (impact): up to 2× quasi-static limits for < 0.5 s
Power limit:
P_max = 80 W (human metabolic rate upper bound per ISO/TS 15066)
At TCP: F_tcp × v_tcp ≤ 80 W
Cobot Hardware Specifications
Universal Robots (UR)
| Model | Payload | Reach | TCP Force | Weight |
|---|
| UR3e | 3 kg | 500 mm | Force sensing ±50N | 11.2 kg |
| UR5e | 5 kg | 850 mm | Force sensing ±150N | 20.6 kg |
| UR10e | 10 kg | 1300 mm | Force sensing ±150N | 33.5 kg |
| UR16e | 16 kg | 900 mm | Force sensing ±250N | 33.5 kg |
Built-in force/torque sensor in base (6-DOF); safety-rated joints
KUKA LBR iiwa
7-DOF; redundant kinematics; torque sensing in all joints
| Model | Payload | Reach |
|---|
| iiwa 7 R800 | 7 kg | 800 mm |
| iiwa 14 R820 | 14 kg | 820 mm |
| Sensitivity: < 0.5 N, < 0.5 Nm in all joints; ISO 10218 PLe | | |
Fanuc CRX Series
CRX-10iA: 10 kg, 1249 mm reach; tablet-based programming; green casing (collaborative mode)
Green-light operation: PFL active; no additional guarding required
ABB YuMi / GoFa
YuMi (IRB 14000): 7-DOF each arm; 0.5 kg/arm; dual-arm; assembly applications
GoFa (CRB 15000): 5 kg, 950 mm; extended PFL cobot
Risk Assessment (ISO 10218-2 Section 5.4)
Required steps:
- Define collaborative workspace and tasks
- Identify hazards (pinch, crush, sharp, speed)
- Estimate severity and probability per ISO 12100
- Apply protective measures in order:
- Eliminate/substitute
- Engineering controls (PFL, SSM, SMS, safeguards)
- Administrative (training, PPE)
- Validate residual risk acceptable
Validation testing:
- Measure TCP force with force plate / calibrated load cell
- Measure contact pressure with pressure measurement film (Fujifilm Prescale or FSR)
- Verify stopping time/distance under worst-case conditions
End-Effector Compliance
Rigid tools → higher impact force → may exceed PFL limits even at low speed
Compliant end-effectors: spring/rubber buffers on tooling; reduces effective mass
Spring compliance k: F_impact = k × v × √(m_eff/k) = √(m_eff × k) × v
Reduce m_eff: tool mass critical in PFL mode; lighter end-effectors preferred
Tool mass effect:
F_impact ∝ √(m_eff) for spring-contact model
Every 50% reduction in end-effector mass → 29% reduction in peak impact force
Payload and Inertia
Effective payload: payload × acceleration = force reaction
At max rated speed/acceleration, joint torques must stay within safety limits
Run-in torque validation: teach program, verify joint torque monitor alarms don't trigger
Application Examples
Pick and place (PFL): speed < 250 mm/s near humans; force monitoring via TCP sensor
Screwdriving (HGP): torque-controlled; operator guides robot to location
Machine tending (SSM): full speed at machine; reduced speed when operator present at load/unload station
Assembly (PFL+SSM hybrid): SSM for approach; PFL for final operation near hands
Output
Provide: collaborative mode selection (SMS/HGP/SSM/PFL), safety distance d_s formula values [m], TCP force limit [N] and pressure limit [N/cm²] by body region per ISO/TS 15066 Table A.2, power limit check [W], recommended cobot model for payload/reach, end-effector compliance requirement, risk level (PLd/PLe per ISO 13849-1), validation test procedure.
