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DC Low Voltage Joint Module

The DC Low Voltage Joint Module integrates a frameless torque motor, strain wave gear, dual absolute encoders, friction brake, and servo drive into one complete actuator. Unlike AC versions that require external drive cabinets, this module houses the drive electronics entirely internally. You simply provide DC bus voltage and an EtherCAT or CANopen connection while the unit independently manages commutation along with the current, velocity, and position loops.

Spanning eight frame sizes from the compact L52I to the heavy duty L170I, this series offers two distinct configurations to match your project budget. The standard I Series includes the complete integrated drive, dual encoders, and brake, Laifual also provides T series joint modules. It is T shape joint module, widely used for 5-axis and 6-axis robotic arms.

Integrated Servo Drive

Every DC Low Voltage module integrates a servo drive inside the module. This is the key difference between the DC Low Voltage Series and the AC High Voltage Series: the DC series integrates the servo drive inside the module, while the AC series requires an external drive cabinet connected through motor phase and encoder wiring.

What the integrated drive eliminates:

External drive cabinet: No DIN-rail servo drive, no cabinet space, no drive-to-motor power cables running through the robot arm
Motor phase cabling: The drive sits millimeters from the motor windings. High-current PWM switching stays inside the shielded module housing, reducing EMI
Drive tuning: Laifual ships each module with pre-tuned current, velocity, and position loops matched to the specific motor-gear-encoder combination in that module
Multi-vendor integration: One joint module integrates the motor, gear reducer, encoder, brake, and drive into a complete actuator, delivering a highly integrated and easy-to-use solution.
Two fieldbus protocols are supported: EtherCAT for high-speed multi-axis synchronization, and CANopen for simpler distributed control architectures.

Integrated Servo Drive DC Low Voltage — Product Overview

Low Voltage L70I-C / L70I-E

Variants: I Series, T Series
Motor Type: Frameless torque DC 24‑48V
EtherCAT / CANopen / CanFD
End effectors
Desktop automation
Smallest frame

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Low Voltage L80I-C / L80I-E

Variants: I Series, T Series
Motor Type: Frameless torque DC 24‑48V
EtherCAT / CANopen / CanFD
Mobile manipulators
Mid‑size cobot arms

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Low Voltage L90I-C / L90I-E

Variants: I Series, T Series
Motor Type: Frameless torque DC 24‑48V
EtherCAT / CANopen / CanFD
Mid‑size cobot arms
AMR‑mounted arms

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Low Voltage L110I-C / L110I-E

Variants: I Series, T Series
Motor Type: Frameless torque DC 24‑48V
EtherCAT / CANopen / CanFD
Industrial cobot joints
Higher torque class

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Low Voltage L142I-C / L142I-E

Variants: I Series, T Series
Motor Type: Frameless torque DC 24‑48V
EtherCAT / CANopen / CanFD
Heavy cobot payloads
Legged robot joints

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Low Voltage L170I-C / L170I-E

Variants: I Series, T Series
Motor Type: Frameless torque DC 24‑48V
EtherCAT / CANopen / CanFD
Largest frame
Maximum torque class

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Frameless Torque Motor

The DC Low Voltage Series uses a frameless torque motor — the rotor and stator are integrated directly into the module without a separate motor frame, shaft, or bearings.

This is not an off-the-shelf servo motor bolted to a reducer. The motor’s rotor mounts on the wave generator input shaft. The stator is pressed into the module. The module’s bearings support both the motor rotor and the Strain wave gear input simultaneously.

This frameless approach eliminates the need for additional bearings, shaft couplings, and mounting flanges typically required in a separate motor-reducer assembly.

For mobile robots where every millimeter of joint diameter and every gram of mass compounds across six or more axes, eliminating these redundant parts matters.

The module typically operates on a 24V–48V DC bus, compatible with battery packs used in autonomous mobile robots (AMRs), legged robots, and portable manipulators.

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Applications

Autonomous Mobile Robots (AMRs)

Battery-powered manipulator arms mounted on mobile platforms. The DC architecture allows direct connection to the vehicle battery system, eliminating the need for an additional AC-to-DC conversion stage. Integrated drives eliminate the need for external drive cabinets, making them ideal for space-constrained mobile robotic platforms.

Spec Overview Table

Module order number CANopen/EtherCat	Encoder Order Number CANopen/EtherCat	Brake Order Number	Motor Order Number
L70l-C	EL-70C-A	BL-70-A	ML-70-A
L70I-E	EL-70E-A
L80I-C	EL-80C-A	BM-80-A	ML-80-A
L80l-E	EL-80E-A
L90I-C	EL-90C-A	BM-90-A	ML-90-A
L90I-E	EL-90E-A
L110I-C	EL-110C-A	BL-110-A	ML-110-A
L110l-E	EL-110E-A
L142I-C	EL-142C-A	BL-142-A	ML-142-A
L1421-E	EL-142E-A
L170I-C	EL-170C-A	BM-170-A	ML-170-A
L170-E	EL-170E-A

Note: Complete torque, speed, and dimension data on individual sub-model Technical Specifications pages.

Frequently Asked Questions

What is the difference between I Series and T Series?

I Series is the standard configuration: integrated servo drive, dual absolute encoders, and friction brake. The T Series uses the same internal configuration, including the motor, gear reducer, encoder, and brake, while featuring a T-shaped housing design. Contact sales for the specific needs

How is the DC Low Voltage Series different from the AC High Voltage Series?

Two differences. First, power: DC series supports 24-48V DC, AC requires AC mains via an external drive. Second, the drive: DC has the servo drive inside the modul, AC sends raw motor phases to an external drive cabinet.

Which communication protocol should I choose?

EtherCAT for high-speed multi-axis applications where cycle times below 1 ms are required — typical in 6-axis robot arms with centralized motion control. CANopen for simpler distributed systems with fewer axes, lower data rates, and less demanding synchronization. Both are digital bus protocols. Specify your protocol at order time; it is configured at the factory.

Can the DC module run directly from a battery?

Yes. The module typically operates on a 24V to 48V DC bus. It is widely used in collaborative robots and other robotic applications requiring compact, integrated, and efficient motion solutions. No inverter, step-down converter, or AC rectification stage is required between the battery and the module. Battery voltage range and current draw per module size are published in the Technical Specifications table on each sub-model page.

Do I need to tune the servo drive myself?

No. Each module ships with pre-tuned current, velocity, and position loops. The tuning parameters are specific to that individual module's motor-gear-encoder combination, set at the factory on a dynamometer. If your application requires different dynamics (softer response for force-limited cobots, stiffer for high-speed pick-and-place), the tuning parameters are accessible over the fieldbus for adjustment.

Is the module sealed against dust and water?

The module housing provides ingress protection appropriate for industrial and laboratory environments. For specific IP ratings per size, refer to the Technical Specifications on each sub-model page. If your application requires a specific IP rating (IP65, IP67), specify at RFQ stage — sealed connector and housing options are available.

What is the lead time for DC Low Voltage modules?

Standard I Series configurations in common sizes and ratios ship within 4 to 6 weeks. T Series and custom protocol configurations may add 1 to 2 weeks. Contact sales with your target size, variant (I or T), and protocol for a confirmed delivery date.