functional safety

Articles, guides, and products tagged "functional safety" — a combined view of every catalogue resource on this topic.

User guide

E-scooter functional safety engineering: safety integrity as the sixth cross-cutting infrastructure axis — IEC 61508:2010 (E/E/PE safety-related systems, SIL 1-4) + ISO 26262:2018 (automotive FuSa, ASIL A-D) + ISO 13849-1:2023 (safety-related parts of machinery, PLr a-e, Cat B/1/2/3/4) + IEC 62061:2021 (SIL CL for machinery E/E/PES) + EN 17128:2020 Annex G (PLEV functional safety requirements) + IEC 60812:2018 FMEA + IEC 61025:2006 FTA + IEC 61709:2017 reliability data + MISRA C:2023 software safety subset + ISO/PAS 21448:2022 SOTIF + IEC 61511 process industry + IEC 60730-1:2024 controls + UL 991 + UL 1998 + DO-178C analogy

Engineering deep-dive into e-scooter functional safety as the sixth cross-cutting infrastructure axis — parallel to [fastener/joining](@/guide/fastener-and-bolted-joint-engineering.md), [thermal management/heat-dissipation](@/guide/thermal-management-engineering.md), [EMC/EMI/interference-mitigation](@/guide/emc-emi-engineering.md), [cybersecurity/interconnect-trust](@/guide/cybersecurity-engineering.md), and [NVH/acoustic-vibration-emission](@/guide/nvh-engineering.md). Covers: 10-row standards matrix (IEC 61508, ISO 26262, ISO 13849-1, IEC 62061, EN 17128 Annex G, IEC 60812 FMEA, IEC 61025 FTA, IEC 61709, MISRA C, ISO/PAS 21448 SOTIF); SIL/ASIL/PL/SIL CL cross-mapping; 6-row hazard-by-subsystem matrix (motor controller throttle-stuck, brake actuator loss, throttle position drift, BMS thermal runaway, display HMI critical info, lighting fail-dark); FMEA worked example for BLE throttle injection scenario; FTA worked example for wheel lock at speed; FMEDA with PFD/PFH calculation, Safe Failure Fraction, Hardware Fault Tolerance; risk reduction equation R_residual = R_unmitigated × (1 - RRF); 6-row mitigation matrix; ALARP principle; software safety V-model + MISRA C:2023 + formal methods; SOTIF (ISO/PAS 21448) as extension to IEC 61508; HIL testing + fault injection; 8-row real-incidents timeline (Lime brake recall 2019, Ninebot ES2 throttle creep 2020, Apollo Pro firmware bug, Boosted board fire, Bird scooter rear-wheel hub crack, Tier scooter motor-stuck); 8-step DIY safety check; 6-step DIY remediation; industry shift 2020→2026; 16 numbered sections.

17 min read

User guide

Display and HMI engineering for electric scooters: sunlight-readability photometry (CR, cd/m², transflective LCD), glanceability ergonomics (ISO 15008, NHTSA 2-glance ≤ 2 s / 12 s, Fitts' law, Frutiger/DIN 1450), adaptive brightness (Weber-Fechner, PWM flicker per IEEE 1789-2015), environmental robustness (IP66, ISO 16750-3 vibration, IEC 60068 thermal −20…+70 °C), EMC (CISPR 14-1, ECE R10) and functional safety (IEC 62368-1, ISO 13849-1)

An engineering deep-dive into the one bidirectional channel between e-scooter and rider — paired with the introductory survey «Display, throttle, and error codes» (parts/display-throttle-error-codes): matrix physics (TN LCD with 90° twisted nematic vs IPS LCD with in-plane molecular switching vs OLED with organic electroluminescence via electron-hole recombination vs E-paper with electrophoretic ink); sunlight readability as a photometric problem (contrast ratio CR=(L_max+L_amb·R)/(L_min+L_amb·R) with ambient reflection, why a 250 cd/m² LCD against 100 000 lx direct sun drops to CR=1.05:1 without an anti-reflective coating, and transflective LCD as a hybrid with ambient backlight); glanceability as safety-critical ergonomics (ISO 15008:2017 in-vehicle visual presentation with minimum character-height-to-distance ratio 1:200, ISO 9241-303:2011 visual ergonomics, NHTSA Driver Distraction Guidelines 2013 + SAE J2364 2-glance principle ≤2 s single + ≤12 s total, Fitts' law T=a+b·log₂(D/W+1) for button-reach time, sans-serif Frutiger 1976 + DIN 1450:2013 Schriften — Leserlichkeit, kerning, x-height ≥60 % cap-height); adaptive brightness (Weber-Fechner logarithmic perception ΔI/I=const, ambient light sensor 0.01-100 000 lx, PWM dimming for LCD backlight with flicker frequency ≥1 kHz per IEEE 1789-2015 No-Observable-Effect threshold); environmental robustness (IEC 60529:2013 IP66 ingress dust-tight+powerful jets, ISO 16750-3:2012 road vehicle mechanical loads 10-2000 Hz random vibration, IEC 60068-2-1/-2 temperature −20…+70 °C cycling, IEC 60068-2-27 mechanical shock 1500g 0.5 ms half-sine, IEC 60068-2-30 damp heat 25/40 °C 95 % RH, ASTM B117-19 salt spray 5 % NaCl 35 °C 96 h); EMC (CISPR 14-1:2020 household-appliance emission, UNECE Regulation 10 Rev 6:2017 vehicle EMC 30 MHz-1 GHz radiated, ferrite chokes for PWM-backlight harmonic suppression); functional safety (IEC 62368-1:2018 hazard-based safety engineering with ES1/ES2 energy-source classes + PS1/PS2 power source + MS1/MS2 mechanical source, ISO 13849-1:2015 PL_d performance level so that display failure does NOT cause throttle/brake loss); and the full comparison matrix of 12 standards (ISO 15008 + ISO 9241-303 + ISO 9241-11 + NHTSA/SAE J2364 + IEEE 1789-2015 + IEC 62368-1 + IEC 60529 + IEC 60068-2 + ISO 16750-3 + CISPR 14-1 + UNECE R10 + ISO 13849-1).

18 min read

User guide

E-scooter motor and controller engineering: BLDC electromagnetics, FOC, KV constant, MOSFET inverter and IEC/UL/ISO/ECE standards

Engineering deep-dive into the e-scooter powertrain — parallel to the introductory overviews «Motors: geared vs direct-drive hub» and «Controller, BMS, display, IoT»: BLDC electromagnetic physics (Lorentz force F=BIL, Faraday EMF ε=-dΦ/dt, Lenz law), KV constant in RPM/V as winding characteristic, torque constant Kt=60/(2π·KV) — why KV 10 on 48 V gives a theoretical 480 RPM/V × 0,95 = 22 N·m/A through mirror symmetry; stator/rotor topology (12-slot 14-pole inrunner vs hub-mount outrunner, NdFeB N42/N48/N52 remanence Br 1.28–1.44 T, ferrite Y30 Br 0.4 T, samarium-cobalt SmCo for high temperatures); three loss types — copper I²R (`P_cu = 3·I²·R_phase`), iron/hysteresis via Steinmetz (`P_h = k_h · f · B^n`, n≈1.6–2.2), eddy currents (`P_e = k_e · f² · B² · t²`); efficiency 85–92 % and why peak efficiency is always near ~50–75 % rated load; thermal management — IEC 60085 insulation class B (130 °C), F (155 °C), H (180 °C), IEC 60529 IP54/65/67 sealing for hub-mounted motors; FOC (Field-Oriented Control) — Clarke transform abc→αβ, Park transform αβ→dq with rotor angle θ, PI controllers for i_d=0 + i_q as torque command, SVPWM (space-vector PWM) modulation; MOSFET inverter — six-MOSFET three-phase bridge, IRFB3077/IPB019N08N3 with RDS(on) 1–5 mΩ, switching losses `0.5·V·I·(t_r+t_f)·f_sw` at 16–32 kHz, dead time 200–500 ns, gate driver 10–15 A peak; DC-link capacitor — ripple current 10–30 A, low-ESR aluminum-electrolytic 1000–2200 μF or polypropylene film; regenerative braking physics — motor as generator, inverter as rectifier, BMS-limited charge acceptance; engineering ↔ symptom diagnostic matrix; full matrix of 9 standards — IEC 60034-1:2022 rotating electrical machines, IEC 60034-30-1 efficiency classes IE1-IE5, UL 1004-1 motors general, UL 1310 Class 2 power units, ISO 21434:2021 road vehicles cybersecurity, IEC 61508 functional safety SIL 1-4, ECE R10 rev 6 EMC + CISPR 14-1, FMVSS 305 high-voltage powertrain, UN ECE R136 L-category propulsion.

18 min read