FEETECH HL-3935 Servo Motor
FEETECH HL-3935 Servo Motor
The HL-3935-C001 is an advanced 12V 35kg-class double shaft constant force serial BUS servo powered by a high-efficiency coreless motor and enclosed in a rugged full-aluminum case for exceptional heat dissipation and durability. Engineered for high-end multi-joint robotics, smart industrial linkages, and precise automation, it features ultra-reliable steel gears with a 1/378 reduction ratio, dual ball bearings, a standard 25T/OD5.9mm horn gear spline, and no mechanical limit angles. Operating over a 9V–12.6V range, it delivers a massive peak stall torque of 35kg.cm and a rated load of 8.5kg.cm at 12V, achieving an impressive no-load speed of 0.117sec/60° (85RPM) and a KT constant of 11.5kg.cm/A. Utilizing a customizable PID control algorithm via digital packets, it communicates through half-duplex asynchronous serial protocol with an ID range of 0–253 and adjustable speeds up to 1Mbps. The servo supports versatile operating modes including angle servo (0–360° position control), motor constant speed, and motor constant current modes, alongside a unique constant force output configuration and multi-loop mode supporting ±7 turns. Delivering an ultra-fine electronic resolution of 0.088°/pulse (360°/4096 steps) with a neutral position at 180° (2048) and clockwise rotation, this 85±1g smart servo outputs comprehensive real-time telemetry feedback — including load, position, speed, input voltage, current, and temperature — via its 15CM connector wire for sophisticated closed-loop robotic control systems.
Common use cases: High-precision humanoid robot arm, leg and torso joints requiring 0.088° resolution and multi-mode control, collaborative robot (cobot) end-effectors with constant force output, industrial automation requiring 12V serial BUS daisy-chain wiring, and applications needing 35kg.cm torque with comprehensive real-time telemetry.
| PRODUCT PARAMETERS | |
| Model | HL-3935-C001 |
| Product Name | 12V 35kg Double Shaft Constant Force Serial BUS Servo |
| Storage Temperature Range | -30℃~80℃ |
| Operating Temperature Range | -20℃~60℃ |
| Temperature Range | 25℃±5℃ |
| Humidity Range | 65%±10% |
| Size | A：40mm B：20mm C：40mm |
| Weight | 85±1g |
| Gear type | Steel |
| Limit angle | No limit |
| Bearing | Ball bearings |
| Horn gear spline | 25T/OD5.9mm |
| Gear Ratio | 1/378 |
| Case | Aluminum |
| Connector wire | 15CM |
| Motor | Coreless Motor |
| Rated Input Voltage | 9V–12.6V |
| No load speed | 0.117sec/60° (85RPM)@12V |
| Running current (at no load) | 200mA@12V |
| Peak stall torque | 35kg.cm@12V |
| Stall current | 3.1A@12V |
| Rated Load | 8.5kg.cm@12V |
| Rated current | 800mA@12V |
| KT constant | 11.5kg.cm/A |
| Terminal resistance | 1.75 Ω |
| Operating Modes | Mode 0: Angle servo mode (default — absolute position 0–360°) Mode 1: Motor constant speed mode (maintains speed as load increases) Mode 2: Motor constant current mode (maintains current as load increases, supports absolute position) |
| Constant force output | Set target torque value (address 44); servo maintains this torque output |
| Multi-Loop Mode | ±7 turns at highest accuracy (power-off turn count not saved; resolution expandable) |
| Command signal | Digital Packet |
| Protocol Type | Half Duplex Asynchronous Serial Communication |
| ID range | 0–253 |
| Communication Speed | 38400bps ~ 1Mbps |
| Control Algorithm | PID |
| Neutral Position | 180° (2048) |
| Running degree | 360° (0~4096 steps) |
| Resolution | 0.088°/pulse (360°/4096) |
| Rotating Direction | Clockwise (0→4096) |
| Feedback | Load, Position, Speed, Input Voltage, Current, Temperature |