236 research outputs found
Development of a Quadruped Robot and Parameterized Stair-Climbing Behavior
Stair-climbing is a difficult task for mobile robots to accomplish, particularly for legged robots. While quadruped robots have previously demonstrated the ability to climb stairs, none have so far been capable of climbing stairs of variable height while carrying all required sensors, controllers, and power sources on-board. The goal of this thesis was the development of a self-contained quadruped robot capable of detecting, classifying, and climbing stairs of any height within a specified range. The design process for this robot is described, including the development of the joint, leg, and body configuration, the design and selection of components, and both dynamic and finite element analyses performed to verify the design. A parameterized stair-climbing gait is then developed, which is adaptable to any stair height of known width and height. This behavior is then implemented on the previously discussed quadruped robot, which then demonstrates the capability to climb three different stair variations with no configuration change
Quasi-Static and Dynamic Mismatch for Door Opening and Stair Climbing With a Legged Robot
This paper contributes to quantifying the notion of robotic fitness by developing a set of necessary conditions that determine whether a small quadruped has the ability to open a class of doors or climb a class of stairs using only quasi-static maneuvers. After verifying that several such machines from the recent robotics literature are mismatched in this sense to the common human scale environment, we present empirical workarounds for the Minitaur quadrupedal platform that enable it to leap up, force the door handle and push through the door, as well as bound up the stairs, thereby accomplishing through dynamical maneuvers otherwise (i.e., quasi-statically) achievable tasks.
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Review article: locomotion systems for ground mobile robots in unstructured environments
Abstract. The world market of mobile robotics is expected to increase substantially in the next 20 yr, surpassing the market of industrial robotics in terms of units and sales. Important fields of application are homeland security, surveillance, demining, reconnaissance in dangerous situations, and agriculture. The design of the locomotion systems of mobile robots for unstructured environments is generally complex, particularly when they are required to move on uneven or soft terrains, or to climb obstacles. This paper sets out to analyse the state-of-the-art of locomotion mechanisms for ground mobile robots, focussing on solutions for unstructured environments, in order to help designers to select the optimal solution for specific operating requirements. The three main categories of locomotion systems (wheeled - W, tracked - T and legged - L) and the four hybrid categories that can be derived by combining these main locomotion systems are discussed with reference to maximum speed, obstacle-crossing capability, step/stair climbing capability, slope climbing capability, walking capability on soft terrains, walking capability on uneven terrains, energy efficiency, mechanical complexity, control complexity and technology readiness. The current and future trends of mobile robotics are also outlined
A literature review on the optimization of legged robots
Over the last two decades the research and development of legged locomotion robots has grown steadily. Legged
systems present major advantages when compared with ‘traditional’ vehicles, because they allow locomotion in inaccessible
terrain to vehicles with wheels and tracks. However, the robustness of legged robots, and especially their energy
consumption, among other aspects, still lag behind mechanisms that use wheels and tracks. Therefore, in the present
state of development, there are several aspects that need to be improved and optimized. Keeping these ideas in mind,
this paper presents the review of the literature of different methods adopted for the optimization of the structure
and locomotion gaits of walking robots. Among the distinct possible strategies often used for these tasks are referred
approaches such as the mimicking of biological animals, the use of evolutionary schemes to find the optimal parameters
and structures, the adoption of sound mechanical design rules, and the optimization of power-based indexes
SWheg: A Wheel-Leg Transformable Robot With Minimalist Actuator Realization
This article presents the design, implementation, and performance evaluation
of SWheg, a novel modular wheel-leg transformable robot family with minimalist
actuator realization. SWheg takes advantage of both wheeled and legged
locomotion by seamlessly integrating them on a single platform. In contrast to
other designs that use multiple actuators, SWheg uses only one actuator to
drive the transformation of all the wheel-leg modules in sync. This means an
N-legged SWheg robot requires only N+1 actuators, which can significantly
reduce the cost and malfunction rate of the platform. The tendon-driven
wheel-leg transformation mechanism based on a four-bar linkage can perform fast
morphology transitions between wheels and legs. We validated the design
principle with two SWheg robots with four and six wheel-leg modules separately,
namely Quadrupedal SWheg and Hexapod SWheg. The design process, mechatronics
infrastructure, and the gait behavioral development of both platforms were
discussed. The performance of the robot was evaluated in various scenarios,
including driving and turning in wheeled mode, step crossing, irregular terrain
passing, and stair climbing in legged mode. The comparison between these two
platforms was also discussed
The Effect of Tail Stiffness on a Sprawling Quadruped Locomotion
A distinctive feature of quadrupeds that is integral to their locomotion is
the tail. Tails serve many purposes in biological systems including propulsion,
counterbalance, and stabilization while walking, running, climbing, or jumping.
Similarly, tails in legged robots may augment the stability and maneuverability
of legged robots by providing an additional point of contact with the ground.
However, in the field of terrestrial bio-inspired legged robotics, the tail is
often ignored because of the difficulties in design and control. This study
will test the hypothesis that a variable stiffness robotic tail can improve the
performance of a sprawling quadruped robot by enhancing its stability and
maneuverability in various environments. To test our hypothesis, we add a
multi-segment, cable-driven, flexible tail, whose stiffness is controlled by a
single servo motor in conjunction with a reel and cable system, to the
underactuated sprawling quadruped robot. By controlling the stiffness of the
tail, we have shown that the stability of locomotion on rough terrain and the
climbing ability of the robot are improved compared to the movement with a
rigid tail and no tail. The flexible tail design also provides passively
controlled tail undulation capabilities through the robot's lateral movement,
which contributes to stability
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