MyActuator RH-17 Hollow Harmonic Actuator (EtherCAT & CAN, Dual Encoder)
MyActuator RH-17 — Integrated Harmonic Joint Actuator
🤖 High-Accuracy Robot Joint · Near-Zero Backlash · Dual 17-bit Encoders
🔍 Product Overview
The RH-17 is a fully integrated harmonic (strain-wave) joint actuator — a complete precision robot joint that combines a brushless motor, a harmonic reducer, dual absolute encoders and an FOC servo driver in one compact, hollow-shaft housing. It is built for the joints where accuracy and repeatability matter more than raw speed: robotic arms, humanoid and quadruped joints, medical and semiconductor equipment, and precision automation. No external drive or controller is needed beyond a CAN / EtherCAT master and a 48 V supply.
⭐ Key Highlights
Peak Torque: 54 N·m (100:1)
Repeat Accuracy: < 0.01°
Backlash: < 40 arc-sec (near-zero)
Encoders: Dual absolute 17-bit (input + output)
Communication: CAN BUS & EtherCAT
🎯 Why "High Accuracy"? The Harmonic Advantage
Strain-Wave Reducer — harmonic gearing meshes many teeth at once through a flexible spline, giving near-zero backlash (< 40 arc-sec) and high torque density that spur or planetary gears cannot match.
Dual 17-bit Encoders — separate input and output absolute encoders measure both motor and joint angle, correcting for flex and delivering < 0.01° repeatable positioning, retained after power-off.
Hollow-Shaft Design — a large central bore routes cables, pneumatics or optics straight through the joint axis for clean multi-joint builds.
📋 Technical Specifications (RH-17-100-E-N-D)
Series / Type | EPS-RH Integrated Harmonic Actuator |
Reduction Ratio | 100:1 (50:1 variant available) |
Input Voltage | 48 V DC |
Rated Torque | 35 N·m |
Peak Torque | 54 N·m |
Rated Speed | 25 rpm |
No-Load Speed | ~30 rpm |
Backlash | < 40 arc-sec (near-zero) |
Encoder Type | Dual — ABS 17-bit input + 17-bit output |
Repeat Position Accuracy | < 0.01° |
Torsional Stiffness | 0.93 × 10⁴ N·m/rad |
Communication | CAN BUS & EtherCAT |
Control Modes | Torque / Velocity / Position |
Brake | Optional (with / without) |
Insulation Grade | Class F |
Multi-turn Memory | Yes (absolute, retained after power-off) |
Approx. Weight | ~1.1 kg without brake (indicative) |
IP Rating | None standard (IP54 on request) |
Integration | BLDC motor + harmonic reducer + dual encoder + FOC driver in one sealed module |
📊 RH Family — Peak Torque at 100:1
Choose the frame size for your joint load — step down to RH-14 for a wrist, up to RH-20/25/32 for shoulders, hips and heavy joints.
Model | Peak Torque (100:1) | Stiffness (×10⁴) | Typical Joint |
RH-14 | 28 N·m | 0.43 | Wrist, gripper, small arm |
RH-17 ★ | 54 N·m | 0.93 | Elbow, forearm, humanoid wrist |
RH-20 | 80 N·m | 1.62 | Shoulder, hip, cobot base |
RH-25 | ~150 N·m* | 3.33 | Heavy arm base, leg joint |
RH-32 | ~300 N·m* | 7.47 | Large humanoid hip/knee |
🧩 Purpose & Real-World Applications
Robotic & cobot arms — elbow/wrist joints for pick-and-place, welding and assembly; the < 0.01° repeatability is what makes automated cells reliable.
Humanoid robots — wrist, torso-rotation and shoulder joints where zero backlash gives lifelike, precise, controllable motion.
Quadruped robots — vibration-resistant integrated design withstands the shock loads of dynamic legged locomotion.
Medical & surgical robotics — surgical arms, imaging gantries and rehab devices needing smooth, exact, backlash-free positioning.
CNC & machine tools — rotary axes, indexing tables and tool changers that must hold tolerance under load.
Gimbals & positioners — camera, antenna, LiDAR and sensor pan-tilt platforms; the hollow bore routes signal cabling through the axis.
📐 Worked Example — Sizing the RH-17 into a Robotic Arm
Scenario: a 6-axis arm must hold a 3 kg payload at 0.5 m reach on its forearm joint. Static joint torque ≈ 3 kg × 9.81 × 0.5 m ≈ 14.7 N·m; with a 2× dynamic + safety factor ≈ ~30 N·m. The RH-17's 35 N·m rated / 54 N·m peak comfortably covers continuous holding and acceleration spikes, while the dual 17-bit encoders keep the tool tip within < 0.01° of commanded position — roughly ±0.1 mm at 0.5 m. For the heavier shoulder joint of the same arm, step up to the RH-20 (80 N·m); for a fine wrist, step down to the RH-14.
🔢 Model Number Decoder
EPS-RH-17-100-E-N-D → EPS = brand (Efficiency·Precision·Smart) · RH = Harmonic series · 17 = frame size · 100 = 100:1 ratio · E = CAN BUS & EtherCAT · N = no brake (B = with brake) · D = dual encoder (S = single).
⚠️ Pre-Order & Price Disclaimer
Imported on demand (pre-order): genuine MyActuator unit imported against your confirmed order with GST invoice, typically shipping in 2–4 weeks. The price shown is an approximate landed-cost estimate and may vary with shipping, logistics and currency exchange — we confirm the exact price before your order is placed. * Weight and RH-25/RH-32 peak-torque values are indicative; full per-model datasheet available on request.
📦 Bulk & Institutional Orders
Building a full humanoid or robotic-arm BOM, or equipping a lab? Reach out for bulk / volume pricing at team@robotechminds.com — we handle multi-unit imports, GST invoicing and institutional (college / research / GeM) procurement.