This paper discusses the concept and parameter design of a robust stair-climbing compliant modular robot, capable of tackling stairs with overhangs. Geometry modifications of the periphery of the wheels of our robot helped in tackling overhangs. Along with establishing a concept design, the robust design parameters are set to minimize performance variations. The Grey-based Taguchi method is applied to provide an optimal setting for the design parameters of the robot. The robot prototype is shown to have successfully scaled stairs of varying dimensions, with overhang, thus corroborating the analysis performed.

Design of a robust stair-climbing compliant modular robot to tackle overhang on stairs

As the demand and market for building maintenance are increasing, automated building facade cleaning has become essential. Robots are replacing human workers because cleaning work on high-rise buildings using gondolas can be dangerous. Several facade cleaning robots have been developed for climbing, and practical knowledge to clean the facade is being adopted in their cleaning devices. In this study, a passive linkage suspension mechanism and tri-star wheels are applied to solve the problems of unclean zones due to failures during overcoming obstacles and the problems through the use of additional actuators. Various mechanism models have been introduced and their performances have been compared based on dynamic simulation considering obstacle encounters.

Performance Comparison of Adaptive Mechanisms of Cleaning Module to Overcome Step-Shaped Obstacles on Façades

This paper documents autonomous multi-floor stairwell ascent by a legged robot. This is made possible through empirically deployed sequential composition of several reactive controllers, with perceptually triggered transitions. This composition relies on simplified assumptions regarding the robot’s sensory capabilities, its level of mobility, and the environment it operates in. The discrepancies between these assumptions and the physical reality are capably handled by the intrinsic motor competence of the robot. This behavior is implemented on the legged RHex platform and experiments spanning 10 different stairwells with various challenges are conducted.

Autonomous Stairwell Ascent

This paper presents a (patent-pending) small, quasi-static, minimal-complexity Stair Climbing Robot (SCR). The vehicle design is given simply by adding a third motor to a (Segway-like) Mobile Inverted Pendulum (MIP), enabling it to maneuver up stairs, leveraging feedback control, by planting it's “foot” onto the ground in front of the next step, lifting the chassis/wheel assembly up it's own “leg”, leaning over onto the top of the next step, self uprighting, and repeating for the following step(s). Fore/aft stabilization during leg balancing is given by using the MIP drive wheels as reaction wheels, while left/right stability is given by the width of the foot itself. The design is small and simple enough to potentially be ruggedized as a stair-climbing throwbot, akin to the Recon Scout (but able to climb up stairs) for reconnaissance in military and homeland security applications.

A minimalist Stair Climbing Robot (SCR) formed as a leg balancing & climbing Mobile Inverted Pendulum (MIP)

In this study, the control of a two-wheeled stair-climbing inverted pendulum robot and its climbing motion are analyzed and discussed. The robot adopts a state-feedback controller with a feed-forwa...

Dynamic modeling and step-climbing analysis of a two-wheeled stair-climbing inverted pendulum robot

Stair Climbing is a key functionality desired for robots deployed in Urban Search and Rescue (USAR) scenarios. A novel compliant modular robot was proposed earlier to climb steep and big obstacles. This work extends the functionality of this robot to ascend and descend stairs of dimensions that are also typical of an urban setting. Stair Climbing is realized by equipping the robot's link joints with optimally designed passive spring pairs that resist clockwise and counter clockwise moments generated by the ground during the climbing motion. This 3-module robot is only propelled by wheel actuators. Desirable stair climbing configurations are estimated a-priori and used to obtain the optimal stiffness for springs. Extensive numerical simulation results over different stair configurations are shown. The numerical simulations are corroborated by experimentation using the prototype and its performance is tabulated for different types of surfaces.

Mihir Shah

Papers

Stair Climbing using a compliant modular robot