# Design and Implementation of A Shape Shifting Rolling-Crawling-Wall-Climbing Robot
## 1 Introduction  
The application of bio-inspired principles towards solving highly complex real world problems has been widely researched for the past couple of decades. Inspiration from nature has greatly advanced developments in mechanism design, overcoming conventional bottlenecks in field robotics. For instance, [PERSON] and [PERSON] presented a cockroach exoskeleton inspired robot for search and rescue missions. The above mentioned robot uses a novel locomotion modality called 'body friction legged crawling' that mimics the cockroach's ability to perform multiple modes of locomotion [1]. Similarly, the work mentioned in [2] discusses the achievement of static stability and leg co-ordination in robots by implementing insect inspired gait motion in the leg. The helical propulsion of E.coli bacteria is used for developing a micro robot system that performs locomotion on a viscous medium [3]. From the author's perspective, the above mentioned micro robot systems with bio-inspired navigation, have vast applications in the biomedical field in the near future. Since spiders perform multiple locomotionsuch as crawling, jumping and vertical surface climbing, the morphological features of spiders are mimicked in the mechanical design of the robots, such that varieties of locomotions can be achieved. For example, the Abigaille II hexapod robotic platform performs vertical climbing, by mimicking the spiders' vertical climbing using their biological dry adhesives [4]. Similarly, a spider-inspired leaping mechanism for jumping robots is mentioned in [5]. Beyond application to robot locomotion, bio-inspired principles have been widely used for the development of novel control paradigms. The work mentioned in [6] describes the development of a bio-inspired controller for a hexapod robot called 'Walknet', which uses artificial neural networks. The author also validated the functioning of the proposed controller using kinematic and dynamic simulations. Similarly, a bio-inspired neurodynamics-based tracking and control method is discussed in [7] for achieving effective tracking and control for the real-time navigation of a non-holonomic mobile robot, in tracking scenarios with large tracking errors. According to the author, the bio-inspired tracking control method can yield zero initial velocity and smooth control signal generation. The biologically inspired spiking neuron-based robot navigation and control is discussed in the work mentioned in [8]. In the above mentioned work, authors investigated the effective usage of a network of spiking neurons in obstacle avoidance, target approaching and visual cue based navigation scenarios. The design philosophy of reconfiguration has been studied and applied to robotics since the early 1980s. Since then, a number of reconfigurable robotic systems have been proposed. Many practical applications prove that reconfigurability is a valuable design strategy. The wheel-track robot mentioned in [9] for urban search and rescue operations epitomises the achievement of dynamic locomotion capability using the reconfigurable principle. The ability of the above mentioned robot to reconfigure itself in a 3D space opens the door for performing complex multi-terrain locomotion. Mechanical design, simulation and experimental validation of a reconfigurable modular hexahedron robot is discussed in [10]. In the above mentioned scenario, the robot's ability to reconfigure itself enables rotational locomotion in addition to the conventional rectilinear motion and clockwise-counterclockwise rotation using omnidirectional wheels. [PERSON] et al. have done consequential work on the dynamic walking gait generation using the reconfigurable [PERSON] mechanism that enables the robot to traverse multiple terrains by varying the link length associated with it [11; 12]. In addition to the adoption of a reconfigurable mechanism in the mechanical design and control, there are also attempts reported to integrate the bio-inspired principles in reconfigurability.