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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. IROS 2015 |
Sri Harsha Turlapati, Mihir Shah, S. Phani Teja, Avinash Siravuru, Dr. Suril V. Shah and Dr. K. Madhava Krishna |
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At the cross section of the fields of Uneven Terrain Navigation and Multi Agent Systems (MAS), in this work, a Detachable Compliant Modular Robot (DCMR) which can perform concurrent scene exploration by detaching into numerous parts, while preserving its ability to climb stairs is proposed and built.
A spring is designed and used in the modular robot taking the worst-case-scenario of stairs encountered in an urban setting. In addition to the actuators at the wheels, an additional set of actuators per module are introduced to enable the detachment and re-attachment. The design additions and their trade-offs are discussed. Potential applications are presented with special focus on improving coverage of a map with obstacles/slabs large enough to merit exploration by climbing them. The problem of turning in crammed spaces is solved using the ability to detach of DCMR. The detaching & re-attaching capability, and stair climbing of the composite modular robot are demonstrated through experimentation using the prototype. Accepted in ICRA 2017 |
Sri Harsha Turlapati, Ankur Srivastava, Dr. K. Madhava Krishna and Dr. Suril V. Shah |
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This work discusses the concept and parameter design of a Robust Stair Climbing Compliant Modular Robot, capable of tackling stairs with overhangs. Modifying the geometry of the periphery of the wheels of our robot helps in tackling overhangs. Along with establishing a concept design, robust design parameters are set to minimize performance variation.
The Grey-based Taguchi Method is adopted for providing 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. IN SUBMISSION |
Ajinkya Bhole, Sri Harsha Turlapati, Rajashekhar V.S, Jay Dixit, Dr. Suril V. Shah and Dr. K. Madhava Krishna |
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This work focuses on enhancing step descending ability of
the modular robot proposed in [16]. The proposed robot
consists of three modules connected with each other through
passive joints. It is propelled using an active pair of wheels
per module. Since there are no actuators at the joints, the
joints are not susceptible to losing operability while traversing on rugged terrain. However with the absence of actua
tors, we face the issue of the robot toppling over when an
abnormally large obstacle is encountered. This shortcoming
is overcome with the use of compliant joints. The com
pliant joints are designed by employing springs of optimal
stiffness, which is calculated through an optimization for
mulation aided with the constraints presented by the static
analysis of the robot. The novelty lies in the systematic
design of compliant joint for step descent. The robot is suc
cessful in climbing and descending obstacles of dimension 17
cm. Simulations of the mathematically modelled robot are
carried out. The results from the same are validated on a
working prototype and presented. AIR 2015 | S. Phani Teja, Sri Harsha Turlapati, Avinash Siravuru, Dr. Suril V. Shah and Dr. K. Madhava Krishna |