Rebar Tying Robot Product

Overview

A rebar tying robot autonomously fastens reinforcing bars at construction joints with wire ties, eliminating manual labor and improving consistency. The system combines a tracked mobile [[rebar-tying-robot-chassis|base]] for site mobility, an [[rebar-tying-robot-positioning-arm|X-Y gantry]] for precision over intersections, and a pneumatic [[rebar-tying-robot-gun-carriage|tying gun]] capable of a tie every 8–12 seconds. Typical job sites include post-tensioned concrete slabs, where 50–100+ intersection points must be tied to lock bar layers before pour; the robot can handle a 3.0 m × 2.0 m section autonomously on a single battery charge.

Mobility and positioning

The Chassis and Gantry is a tracked rover frame with differential Differential Drive (left and right [[rebar-tying-robot-drive-motor|BLDC motors]]) driving independent [[rebar-tying-robot-track-left|rubber tracks]]. The tracks provide traction over rough formwork edges and small rubble; the differential drive allows point-turn steering. A mounted [[rebar-tying-robot-gantry-rail-x|horizontal rail]] and [[rebar-tying-robot-gantry-rail-y|vertical lift column]] serve as the positioning reference.

Over the rail runs the gun carriage, driven by stepper-powered [[rebar-tying-robot-x-actuator|X-axis]] and [[rebar-tying-robot-y-actuator|Y-axis]] ballscrews with [[encoder|position feedback]] to ±2 mm. The Rebar Detection Vision module—a forward-facing RGB camera—detects rebar grid lines using a trained neural network; the Motion Controller triangulates intersection candidates and drives the gantry stepwise to each point.

Tying mechanism

The Gun Carriage houses a pneumatic [[rebar-tying-robot-gun-head|wrap head]] with a rotating hook that twists a pre-bent wire around the crossing bars. The sequence:

1. [[rebar-tying-robot-feed-motor|Wire feed]] pulls ~15 cm of fresh wire from the Wire Spool.
2. [[rebar-tying-robot-gun-clamp|Clamp jaws]] hold the wire ends in position.
3. The wrap head rotates 3–4 times under pneumatic power, circling the wire around both bar legs.
4. A [[rebar-tying-robot-cut-solenoid|pneumatic cutter blade]] severs the tie, and the clamp releases.
5. The twisted joint is secured with no excess wire—a key advantage over hand-tying, which leaves loose ends.

The [[rebar-tying-robot-pneumatic-circuit|pneumatic system]] includes an onboard [[rebar-tying-robot-compressor|0.5 hp electric compressor]] and [[rebar-tying-robot-air-tank|10 L buffer tank]] maintaining 4.0 bar. Air demand is ~20 L/min on cycle, so the compressor duty cycle is ~40 % — sufficient for 150–200 ties/hour.

Vision and autonomy

The forward [[rebar-tying-robot-vision|camera]] at ~40 cm standoff from the gantry plane images the rebar grid in ambient light, supplemented by a [[led-ring|ring light]] for shadow suppression. A neural model trained on thousands of grid photos identifies bar crossings with 95 % confidence; the controller then commands the X-Y gantry to position the gun 1–2 cm above the crossing. A short height-finding routine confirms the gun is on-plane, then the wrap cycle executes.

Missed ties and slipped positions are tracked: the robot logs every attempted tie, confidence score, and visual post-check. If three consecutive ties fail at a location, it flags the operator—usually a sign the bars are misaligned or the location is inaccessible.

Battery and endurance

The [[rebar-tying-robot-battery|pack]] is 48 V LiFePO4 with 200 Ah capacity (9.6 kWh), providing 8–10 hours of operation on a typical 3.0 m × 2.0 m slab (roughly 200–250 ties). Travel consumes ~200 W, tying ~150 W (motors + compressor), so the average power is ~350 W, yielding a nominal 27 hour pack life; real-world endurance is shorter due to compressor inefficiency and gantry peak loads.

Site integration

The robot is transported on a flatbed and deployed at the formwork edge. It requires 3-phase 480 VAC shore power for overnight charging (4 hour recharge from 20 %), but runs fully autonomous during the day. An operator loads the [[rebar-tying-robot-wire-spool|wire spool]] (pre-staged at the job) and inputs the grid pattern (captured from CAD or a site scan) via a rugged tablet; the system then maps its position relative to the gantry home and begins autonomous tying.

[[rebar-tying-robot-safety|Safety contact bumpers]] on the front halt the rover if it strikes a worker or obstruction. A mushroom [[rebar-tying-robot-estop-button|e-stop button]] cuts main power, and the onboard [[mcu|safety MCU]] prevents restart without manual reset.