Browsing by Author "Uğur, Mustafa"

Now showing 1 - 4 of 4

Open Access
Control and study of bio-inspired quadrupedal gaits on an underactuated miniature robot
(Institute of Physics, 2023-01-25) Askari, Mohammad; Uğur, Mustafa; Mahkam, Nima; Yeldan, Alper; Özcan, Onur
This paper presents a linear quadratic Gaussian (LQG) controller for controlling the gait of a miniature, foldable quadruped robot with individually actuated and controlled legs (MinIAQ-III). The controller is implemented on a palm-size robot made by folding an acetate sheet. MinIAQ-III has four DC motors for actuation and four rotary sensors for feedback. It is one of the few untethered robots on a miniature scale capable of working with different gaits with the help of its individually-actuated legs and the developed controller. The presented LQG controller controls each leg’s positions and rotational speeds by measuring the positions and estimating the rotational speeds, respectively. With the precise gait control on the robot, we demonstrate different gaits inspired by quadrupeds in nature and compare the simulation and experiment results for some of the gaits. An extensive simulation environment developed for robot dynamics helps us to predict the locomotion behavior of the robot in various environments. The match between the simulation and the experiment results shows that the proposed LQG controller can successfully control the miniature robot’s gaits. We also conduct a case study that shows the potential to use the simulation to achieve different robot behavior. In a case study, we present our robot performing a prancing similar to horses. We use the simulation environment to find the required motor configuration phases and physical parameters, which can make our robot prance. After finding the parameters in simulation, we replicate the configuration in our robot and observe the robot making the same moves as the simulation. © 2023 IOP Publishing Ltd.
Open Access
Effect of feet failure and control uncertainties on the locomotion of multi-legged miniature robots
(Institute of Electrical and Electronics Engineers, 2022-03-09) Mahkam, Nima; Uğur, Mustafa; Özcan, Onur
This study investigates the effects of control uncertainties and random feet failures on the locomotion of the multi-legged miniature robots. The locomotion analyses results are verified with our modular multi-legged miniature robot with a soft/hybrid body named SMoLBot. A single SMoLBot module is 44.5 mm wide, 16.75 mm long, and 15 mm high with two individually actuated and controlled DC motors. This individual actuation makes it feasible to run with any imaginable gait, making SMoLBot a nice candidate for gait study analyses. The presented locomotion study shows that the effects of control uncertainties and feet failures are highly dependent on the total number of legs and the type of backbone attached to the robot, e.g., increasing the total number of legs or utilizing a rigid backbone on the robot helps the robot to walk faster compared to similar robots with soft backbones or the ones with fewer modules. This study presents a guide to the researchers on the effects of feet failures and control uncertainties on the locomotion of soft/hybrid multi-legged miniature robots.
Open Access
Effects of compliance on path-tracking performance of a miniature robot
(IEEE - Institute of Electrical and Electronics Engineers, 2023-05-15) Uğur, Mustafa; Arslan, Burak; Özzeybek, Alperen; Özcan, Onur
Path-tracking is often challenging in miniature robots because their feet or wheels tend to slip due to the low robot weight. In this work, we investigate the effect of c-leg compliance on path-tracking performance and the obstacle-climbing capabilities of our foldable and miniature robot with soft, c-shaped legs. With its 82 mm x 60 mm x 29 mm size and 29.25 grams weight, a single module of our robot is one of the smallest untethered miniature robots. Our results show that utilizing soft c-shaped legs provides smooth path-tracking performance, similar to a wheeled differential drive robot. However, modules with rigid c-shaped legs are affected significantly by the impact and slip between the leg and the ground, and they perform rather unpredictably. Additionally, modules with wheels cannot climb obstacles 1 mm or larger. We show that using soft legs enhances the obstacle climbing skills of modules by climbing a 9 mm obstacle, while the module with rigid legs can only climb a 7 mm obstacle. These path-tracking abilities and obstacle-climbing capacity support our vision to build a reconfigurable robot using these modules.
Open Access
ReMBot: A reconfigurable, miniature, modular robot with soft connection mechanisms
(2023-07) Uğur, Mustafa
Nature has been a valuable source of inspiration for engineers, leading to the development of diverse materials, mechanisms, and algorithms that have enhanced human life. One fascinating idea borrowed from nature is the collaborative work of ant colonies. Ants work together to accomplish tasks that are impossible to achieve individually, such as constructing bridges by connecting to one another. Researchers have been motivated by such examples to create reconfigurable robots that can perform various exciting tasks, such as climbing stairs, crossing gaps, moving objects, and assisting in furniture building, by moving as separate modules and docking to each other using different connection mechanisms. However, the connection mechanism remains a challenge. Many of the existing designs re-quire an actuator or a driving circuit which makes the control harder and limits the robot’s motion. This thesis presents ReMBot: A self-reconfigurable, miniature, modular robot with a soft connection mechanism. The robot comprises multiple modules, each equipped with backbones featuring permanent magnets. Using permanent magnets offers reconfigurability without requiring additional power, actuation, or a driving circuit while enhancing the robot’s compliance. The modules, including the body, electronics, actuators, c-shaped soft legs, and backbones with magnets, weigh 29.43 grams and have 82 mm x 60 mm x 14.7 mm dimensions. These module specifications, combined with the whole system design, allow ReMBot modules to execute path-tracking tasks, dock and undock, and sense the connection between modules. Their ability to connect and maintain a longer structure enables the ReMBot to climb obstacles higher than itself. Soft c-shaped legs enable modules to dock successfully by ensuring successful path-tracking tasks while they help them to move in different terrains like gravel, sand, or grass. The modules’ miniature structure, ease of manufacture, and affordability make them a suitable option for multiple use cases. The robot’s wireless communication capability makes it a strong contender for surveillance in confined spaces like collapsed buildings and nuclear sites, large areas like farmlands, and even planetary exploration missions.