Source-linked AI summary
QLAUN: A Research-Oriented, Robust, Agile, Modular, and Affordable Torque-Controlled Quadruped Robot
Mohamad S. Moudallal, Noel J. Maalouf
TL;DR
Affordable research platforms are needed amid financial barriers for smaller institutions and a stated shortage of low-cost quadruped legs that combine robustness and agility. The paper presents QLAUN, a modular quadruped with 3D-printed electronics-free legs and QDD actuation. It is intended to support locomotion, SLAM, and terrain-analysis research, with an open-source initiative planned.
Problem
Low-cost 3D-printed quadruped legs that combine robustness and agility are described as lacking, while legged-robotics research is financially challenging for smaller institutions.
Source: §I · pp. 1–2Method
QLAUN combines torque-controlled QDD actuation with modular, 3D-printed electronics-free legs that can be replaced by custom legs.
Source: §I · p. 2, A. Actuator Design · p. 2, B. Leg Design · p. 2Results
The paper presents QLAUN as a novel 3D-printed, torque-controlled quadruped intended to balance robustness and agility.
Source: §I · p. 2Takeaways & Limitations
The authors intend QLAUN to support robust-locomotion, SLAM, and terrain-analysis research, with designs and software offered through an open-source initiative.
Source: §III · p. 2
Abstract
from arXiv · showhide
QLAUN Bot (Quad-Legged Adaptive Unmanned Navigator Robot) is a torque-controlled quadruped robot that is research-oriented, cost-effective, and aimed at achieving simultaneous robustness and agility while being completely 3D-printed. It is a quadruped robot that is aimed at empowering robotics research at universities and research institutes in Lebanon and the MENA region. Using a novel electronics-free leg design strategy, we present a modular robot with interchangeable and easily replaceable legs. The 15 kg robot possesses 12 DoF (Degrees-of-Freedom) with three per leg, each paired with a completely 3D-printed Quasi-Direct Drive (QDD) actuator that consists of a brushless DC motor and a low-ratio gearbox transmission that is connected to a belt transmission system for significantly increasing the torque outputs at the joints. We present legs that have decoupled hip and knee actuators to improve the overall modularity of the robot. QLAUN is almost completely 3D-printed using polylactic acid (PLA) and assembled using off-the-shelf parts to create a robust, agile, and affordable robot for legged robot locomotion research. The legs possess joints with wide ranges of motion, including a continuous hip flexion-extension joint. A compliant foot, printed using TPU-95A is also implemented for alleviating hard impacts and handling terrain uncertainties. This extended abstract aims to introduce QLAUN, a novel platform for robotics research, emphasizing the design concepts and principles that underpin its development to the academic and research communities in the field of robotics.
I. INTRODUCTION
The introduction presents QLAUN as an affordable, modular, 3D-printed torque-controlled quadruped intended to balance robustness and agility. It situates the design amid constraints on research funding, trade-offs among existing robots, and a shortage of low-cost legs combining robustness and agility.
- Quadruped development spans mechanical design, control, perception, and planning, with mechanical design identified as critical because it dictates passive locomotion.Source: §I · p. 1
- The introduction describes prismatic, articulated, and redundant articulated leg configurations, with the latter adding a joint and link resembling an animal ankle and foot.Source: §I · p. 1
- Research on quadrupeds is financially challenging for smaller institutions, while open-source robots such as SOLO have supported locomotion research.SOLO is described as a 2.2 kg, research-oriented, affordable, lightweight quadruped [1].Source: §I · pp. 1–2
- Many quadrupeds prioritize agility, speed, and mobility over payload; 50 kg Kirin carries up to 125 kg but is described as dramatically less agile.Kirin uses prismatic legs, unlike agility-oriented robots such as StarlETH, ANYmal, and Spot [6].Source: §I · p. 2
- Low-cost 3D-printed quadruped legs that are both robust and agile are described as lacking, alongside scarce versatility and payload-to-weight ratios above unity.Source: §I · p. 2
- QLAUN is introduced as a research-oriented, affordable, modular, 3D-printed torque-controlled quadruped designed to balance robustness and agility.Source: §I · p. 2
A. Actuator Design
The actuator combines a brushless motor, printed planetary gearbox, and encoder in a QDD assembly, with helical gears and BLDC drivers supporting its operation.
A. Actuator Design
- The QDD actuator combines a 330KV, 600W brushless DC motor, a 3D-printed 8:1 planetary gearbox, and a 2048PPR incremental encoder.The cited motor is the mjbots MJ5208 and the encoder is the AMT 103-V.Source: A. Actuator Design · p. 2
- Helical gearbox gears are described as improving torque output and reducing backlash; ODrive Pro BLDC drivers provide Field-Oriented Control.Source: A. Actuator Design · p. 2
- At 20V, the actuator can draw up to 30A and provides up to 5N.m while limited to 40% of full power capacity.The passage reports dimensions of around 85cm in diameter and 65cm tall.Source: A. Actuator Design · p. 2
B. Leg Design
QLAUN’s RAPID leg is a 3D-printed, electronics-free design that combines decoupled hip and knee joints with a bolt-on modular interface.
B. Leg Design
- The RAPID leg is presented as a completely 3D-printed, electronics-free design with hip abduction-adduction, hip flexion-extension, and knee flexion-extension joints.Source: B. Leg Design · p. 2
- A 1:1 thigh-to-shank ratio follows the cited canine-mammal proportion, while belts decouple hip and knee joints and provide 4:1 ratios for a stated 32:1 total ratio.Source: B. Leg Design · p. 2
- Three bolts allow researchers to swap the leg for a custom design; the leg uses PLA, off-the-shelf parts, and a compliant TPU-95A foot.Source: B. Leg Design · p. 2
C. System Design
The 3D-printed chassis is presented as a customizable structure for research configurations, including sensor arrays and manipulator arms.
C. System Design
- The chassis is described as accommodating custom configurations ranging from specialized sensor arrays to complex manipulator arms.Source: C. System Design · p. 2
- QLAUN is reported to weigh approximately 15 kg and measure 38 cm tall, 77 cm long, and 38 cm wide.Source: C. System Design · p. 2
- The authors position the adaptable platform for experiments on leg topologies and sensor integration, in laboratory and real-world applications.Source: C. System Design · p. 2
III. CONCLUSION & FUTURE WORKS
QLAUN is presented as a robust, agile, and affordable platform for legged-locomotion studies, with intended applications spanning several research areas. Its designs and software are planned for global release as an open-source initiative.
- QLAUN is intended to support legged-locomotion research and diverse experimental studies, starting at the Lebanese American University and extending across MENA.Source: §III · p. 2
- The platform is intended to support research projects in robust locomotion, SLAM technologies, and terrain analysis.Source: §III · p. 2
- QLAUN is planned as both a ready-made product and an open-source initiative providing designs and software to the global research community.Source: §III · p. 2