Fielding Lynx M20 in Harsh Sites: A No‑Surprises Acceptance and Operations Playbook

When quadrupeds leave the lab and step into winter yards, wet stairs, and sun‑baked catwalks, surprises get expensive. For DEEP Robotics’ Lynx M20, publicly posted, model‑specific specs are sparse, while expectations—multi‑hour patrols, all‑weather routes, and reliable stairs—are high. That gap puts a premium on tight acceptance testing and disciplined field operations. Done right, teams can tune for ice, compact snow, loose sand, mud, and wet stairs before the first mission and keep uptime steady through seasons.

This article delivers a practical playbook to make that happen. It covers scoping payload and center of gravity, surveying routes by slope and substrate, and running acceptance trials that include cold‑soak starts, hot‑run stamina, ingress checks, and stair safety. It then details substrate‑specific trials with pass/fail criteria, foot selection and changeover workflows, gait libraries and speed limits per terrain, operator checklists for daily readiness and recovery, a lean field toolkit, and telemetry habits for ongoing reliability. The goal: eliminate guesswork, set conservative planning values, and validate the exact M20 configuration you’ll field.

Mission Scoping: Payload, Center of Gravity, and Site Constraints

Start by constraining the problem you actually need to solve.

• Define payload mass and placement. Inspection payloads in this class commonly range from 2–10 kg. Treat this as the working envelope and verify the M20’s specific limits with a signed datasheet. Keep heavier components low and centered to maintain the center of gravity (COG) within the support polygon.
• Map the COG. With the intended mast, LiDAR, and compute onboard, verify the COG longitudinally and laterally. Small shifts matter on stairs, on slopes beyond 20°, and on deformable substrates such as snow and sand. Plan to derate speed and slope margins as payload approaches 10 kg.
• Establish environmental planning values. Specific M20 IP and temperature ranges are not publicly posted. For planning, use industrial‑class norms: operation roughly from –20 °C to +45 °C, IP66–67‑class sealing, and stairs/ramps typical of industrial quadrupeds. Require certificates and run site‑representative validation.
• Set mobility targets by substrate. On dry, rough surfaces, plan slopes up to 30°. Derate to ≤ 20° when wet. On loose sand or compact snow without studs, plan ≤ 10–15°. For steps, plan 20–25 cm and validate standard stairs (17–20 cm risers), including when wet.
• Energy expectations. No public M20 Wh figure or charge profile is available. For inspection gaits at 0.3–1.0 m/s with modest payloads, assume multi‑hour endurance with notable derating in deep cold, loose sand, mud, and hot weather. Bake validation into the acceptance program.

Pre‑Deployment Survey: Surfaces, Slopes, Obstacles, Microclimate

Walk the route before the robot. A thorough survey becomes your acceptance test script and your operations manual.

• Build a surface catalog. Segment the route by dominant substrate: dry concrete, wet stairs (metal/tile), glare ice, compact snow, loose sand/gravel, and mud/slurry. Note contaminants like standing water, oils, or grit.
• Measure slopes and step geometry. Record grade by segment (degrees, not just “steep”). Capture step height ranges: curbs (5–15 cm), stairs (17–20 cm riser), and one‑off obstacles (15–30 cm). Mark maximum sustained grades and any transitions (e.g., flat to 15° ramp to stairs).
• Identify obstacles and pinch points. Railings, conduit, cables, and gratings affect footholds and body clearances. Catalog widths and overhangs that could contact masts or cameras.
• Map microclimates. Cold sinks, shaded ice patches, wind‑scoured corners, and solar‑exposed corridors create local thermal and traction extremes. Flag recurring wet zones that turn slick after rain.
• Note altitude effects. At ≥ 3,000 m, reduced air density cuts convective cooling. Expect derated sustained speeds and steeper thermal rise on long climbs. Plan rest intervals and enhanced monitoring.

Your survey artifacts—photos, measurements, and substrate tags—become the backbone of acceptance trials and gait/foot configuration by segment.

Acceptance Tests: Cold‑Soak, Hot‑Run, Ingress, Slopes, and Steps

Treat acceptance as a certification you perform for your site, payload, and climate.

• Cold‑soak start and cold‑run. Soak the robot at –25 °C for 8 hours. Validate start‑up success, warm‑up time, perception readiness (defog/demist), and runtime at –20 °C across flat surfaces and compact snow. Log pack temperature, heater duty, voltage sag, average Wh/km, and slip events.
• Hot‑run stamina. Operate at +45 °C (or replicate solar load) to assess sustained speed, thermal headroom, and throttling. If relevant, test at ≥ 3,000 m altitude. Log motor/drive temperatures and any thermal derates.
• Ingress and splash. Align controlled rain/splash tests with the claimed IP code once obtained. Verify wading depth limits and post‑test water ingress at seams and connectors. Confirm connector sealing practices and inspect for dust intrusion.
• Slopes and steps. On dry rough concrete, test slopes from 0–35°. On wet surfaces, test up to 20°. For steps, test 15–30 cm obstacles and standard stairs (17–20 cm), both dry and wet. Record slip incidence, base tracking error, gait stability margins (COG vs support polygon), and recovery behavior.
• Energy profiling. At 0.3/0.6/1.0 m/s on representative substrates, measure Wh/km and average power at 20 °C; repeat at –20 °C and +45 °C. Profile charging times 10–90% and 10–100% at 20 °C; evaluate cold‑charge behavior near 0 °C per battery management system limits.

Acceptance outcomes should be binary for mission go/no‑go, with clear caveats (e.g., “winter routes require studded feet and ≤ 10° slopes”). Repeat trials enough times to see variability and to verify that mitigations (feet, gaits) hold across cycles.

Substrate Trials: Ice, Snow, Sand, Mud, and Wet Stairs

Document substrate‑specific performance with the feet and gaits you intend to run. Use the table below to structure pass/fail and notes.

Substrate	Setup and test focus	Planning limits	Pass indicators	Fail indicators
Glare ice	Fit microspike/studded feet; use low‑speed, no‑brake gaits on descents	Severely derated without studs; avoid steep descents	Controlled starts/stops; minimal slip events; no uncontrolled sliding	Repeated uncontrolled slides; self‑righting required; inability to hold on mild grade
Compact snow	Use wide or spiked feet; increase stance margins	Derate slope to ~10–15°; energy per km increases	Stable footholds with occasional clearable buildup; predictable tracking	Excessive sinkage; frequent slip recoveries; pack snow fouls feet beyond recoverable behavior
Loose sand/gravel	Use larger feet; longer stance; lower duty factor	Lower max grade; 30–100% energy penalty vs flat	Forward progress without recoil slip; manageable heat	Wheel‑spinning‑like slip; thermal throttling; bogging
Mud/slurry	Use aggressive tread; plan washdowns	Energy rises; suction/fouling risks	Consistent extraction from foot placements; seals remain cleanable	Suction stalls; abrasive grit intrudes; contaminated footpads/seals
Wet stairs (metal/tile)	Choose abrasive feet; reduce speed; fit lens hoods/wipers	Lower speed; slip risk on descents	Stable, repeatable stair cycles; no sudden braking	Missed footholds; slides on landings; camera occlusion causes navigation dropouts

Keep the test gaits repeatable by segment and speed, and compare Wh/km and slip/recovery density to flat, temperate baselines. Expect runtime penalties from roughly 1.2× on wet stairs to 1.5–1.8× on compact snow, with further derating in deeper snow or viscous mud.

Foot Selection and Changeover Workflow

The right feet are decisive; the wrong ones turn slopes and stairs into incident reports.

• Keep a feet kit: rubber/general‑purpose, abrasive for wet stairs, microspike/studded for ice, and larger‑area feet for snow/sand.
• Match feet to substrate segments from the survey. Where surfaces change (e.g., indoor tiles to outdoor metal grating to icy stairs), define changeover points and timings in the route plan.
• Enforce a clean‑change protocol after mud or slurry. Implement washdowns and remove packed material before reentering drier segments to avoid contamination and slip.
• Inspect feet for wear, torn treads, or loosened studs before every run and during mid‑shift checks in harsh missions.
• Protect sealing. Confirm that feet changes don’t compromise adjacent seals and that any leg or foot fasteners are secured per torque guidance.

Gait Libraries and Speed Limits per Substrate and Incline

Configure locomotion to the surface instead of asking a generic gait to do everything.

• Start with inspection gait norms. Sustained speeds around 0.8–1.0 m/s are typical in this class for flat, dry routes; 0.3–1.0 m/s covers most inspection needs. Reserve short bursts to ~1.5–2.0 m/s for recovery or crossings if thermal headroom allows.
• Program slope bands. Use up to 30° on dry rough surfaces as a validation target; ≤ 20° when wet; ≤ 10–15° on compact snow or loose sand without studs. Where actual site geometry exceeds these bands, segment the route or add physical mitigations (e.g., anti‑slip treads on stairs).
• Ice rules. On glare ice, enforce low‑speed, no‑brake gaits and studded feet. Avoid steep descents and limit slope transitions that induce braking. Increase stance time and reduce swing aggressiveness to improve contact establishment.
• Snow and sand. Increase stance margins, widen body stance where available, and plan slower, steady forward motion to reduce sinkage and recoil slip. Monitor thermal rise due to higher power draw.
• Wet stairs. Switch to stair‑specific gait patterns with reduced speed, precise foothold placement, and minimal stopping/starting on landings. Favor abrasive feet.
• Heat and altitude. Incorporate thermal models into the planner; derate sustained speed on long climbs and at high elevation. Watch motor and pack temperatures for throttling onset.

Tune contact gains, slip thresholds, and swing trajectories per substrate. Ensure terrain classification triggers the correct gait library automatically, with manual override available.

Operator Checklists: Daily Readiness, Cleaning, Post‑Run Inspection

Discipline is your friend. Use concise checklists to keep missions predictable.

Pre‑run

• Battery SOC and temperature in nominal range; packs pre‑warmed in cold conditions; avoid charging below 0 °C without battery heating.
• Feet matched to the day’s route; spare set staged; studs inspected.
• Optics clear; demist/heater functions verified; lens hoods/wipers fitted for wet routes.
• Connectors fully seated and weatherized; port seals intact.
• Sensor suite and autonomy map loaded; route segments tagged by substrate.
• Telemetry logging enabled (power, Wh/km, temps, slip events, estimator health).

Mid‑run (harsh missions)

• Spot‑check foot fouling in mud/snow; remove packed material.
• Review thermal logs at natural pauses; assess derate risk in heat or at altitude.
• Confirm optics remain clear in rain, snow, and spray.

Post‑run

• Washdown and drying as needed; avoid forcing water past seals.
• Inspect feet, leg joints, and sealing surfaces for grit, wear, and damage.
• Review logs: slip/recovery density, base tracking error, Wh/km by segment, pack temperature/voltage sag, heater duty in cold.
• Flag anomalies for the next acceptance re‑test and gait/foot retuning.

Field Toolkit and Spares

Keep the kit lean but decisive. 🧰

• Feet variants: general‑purpose rubber, abrasive, studded/microspike, large‑area snow/sand.
• Optics care: lens hoods or wipers for wet routes; cleaning materials and demist checks.
• Sealing essentials: port/connector weatherization as supplied by the platform; protective caps for unused ports.
• Thermal aids: provisions to pre‑warm packs in winter and provide shade/airflow in heat.
• Data and power: storage for logs; chargers aligned to pack limits; spares per your cycle‑life planning once obtained from the vendor.

Specific charger wattages, pack Wh, swappability, and certified IP hardware accessories are not publicly listed for the M20; confirm during procurement and include them in the kit once specified.

Telemetry Habits: What to Log, Thresholds, and Review Cadence

Logging turns field time into reliability.

• What to log. Power and energy (average W, Wh/km), pack temperature and heater duty in cold, motor/drive temperatures, voltage sag under load, slip events and recovery triggers, estimator health (base tracking error, COG vs support polygon margins), terrain classification, and gait state.
• Thresholds and alerts. Set alerts near known derating/onset points for the platform: thermal margins in heat/altitude and pack cold limits for charging. On ice and wet stairs, treat repeated slip recoveries and rising base tracking error as triggers to slow gaits or abort segments.
• Compare to baselines. Use temperate, flat runs as your control. Expect roughly 1.2× energy on wet stairs/ramps, 1.5–1.8× on compact snow, and higher in loose sand and mud. Large deviations point to mechanical or environmental changes worth investigating.
• Incident reviews. After any uncontrolled slide, fall, or thermal throttle, replay logs by segment and update feet/gait selections or route timing. Repeat the relevant acceptance test to verify the fix.
• Trend over seasons. Track Wh/km, slip density, and thermal headroom across months. Adjust start times, gait speeds, and segment limits as microclimates shift.

Quick Planning Values (To Validate Onsite)

Use these conservative values to seed your plan; convert them into site‑specific limits after acceptance.

• Sustained inspection speed: 0.8–1.0 m/s on flat, dry surfaces; 0.3–0.6 m/s in slippery or deformable conditions.
• Slopes: up to 30° dry; ≤ 20° wet; ≤ 10–15° on compact snow or loose sand without studs.
• Steps: plan 20–25 cm; validate standard stairs (17–20 cm risers), wet and dry.
• Cold operation: include pack pre‑warming and optics demist; expect runtime reduction and slower gaits at –20 °C.
• Hot operation: expect thermal overhead and potential speed/grade derates near +45 °C, amplified at high altitude.

For runtime planning, a multi‑hour class robot with usable energy on the order of 1.0–1.6 kWh typically delivers about 4–6+ hours on flat, temperate routes at inspection speeds, with penalties from 1.2× to 1.8× in slippery or deformable terrains. Treat these as starting points and validate with your payload.

Conclusion

Putting a quadruped on ice, snow, mud, and wet stairs without drama takes more than hope—it requires a site‑specific acceptance plan, substrate‑aware configuration, and daily operational discipline. Lynx M20 targets outdoor industrial inspection, but model‑specific environmental and energy specs are not publicly posted. The right response is to lock down conservative planning values and then prove, with your payload and terrain, that the configuration holds in cold‑soak starts, hot‑run endurance, ingress exposure, slopes, and steps.

Key takeaways:

• Treat acceptance as your certificate: cold, hot, wet, slopes, steps—with logs.
• Match feet and gaits to substrates; predefine changeovers where surfaces shift.
• Use conservative slope and speed bands; derate aggressively on ice, snow, and sand.
• Make telemetry actionable: energy, thermal, slip, and estimator health by segment.
• Keep a small but decisive field kit—feet variants, optics care, and sealing essentials.

Next steps: obtain the M20 datasheet and certifications; instrument the first onsite acceptance campaign with your payload; tune feet, gaits, and thermal strategies for each route segment; and formalize the operator checklists and telemetry reviews. With those pieces in place, the Lynx M20 can deliver predictable patrols across seasons and substrates, turning harsh sites into routine routes.

Sources & References