C-Legged Hexapod Robot Design Guidelines Based on Energy Analysis

Andres Vina,Antonio Barrientos

doi:10.3390/app11062513

Andres Vina, Antonio Barrientos

Open Access

https://doi.org/10.3390/app11062513

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Abstract

C-legged hexapod robots offer a balanced trade-off between the robust stability of wheeled robots and the increased-motion capabilities of legged robots, and therefore, are currently of great interest. This article investigates the impact of mass, leg radius, and angular velocity on the energy consumption of C-legged hexapod robots, in order to develop a set of design guidelines that maximize the robot’s performance. The kinematic model of a single C-leg system is obtained and used to determine the system’s energy consumption associated with gravitational potential energy (GPE) and kinetic energy (KE) variations. Both the kinematic model and energy model are validated in a custom-made test bench. Our results show that the kinematic model very accurately predicts the trajectory of the system in space, but due to the varying load experienced by the motor, the system lags compared to the model predictions. Furthermore, the energy model has been also validated experimentally and successfully predicts the motor consumption periods. Using the energy model, it has been concluded that the angular velocity of the leg and the leg radius have an exponential relationship with motor peak power demand—directly affecting the motor selection. On the other hand, the mass is inversely proportional to the robot efficiency, and therefore, must be kept as low as possible.

Highlights

In recent years, the development and investigation of a large variety of mobile robots used in a wide diverse set of applications have been enhanced by electronics cost reduction, increased microchips computational capabilities, and intelligent and flexible manufacturing [1]
The objective of this article is to provide the reader with an understanding of the motion and energy consumption of hexapod robots, together with some design considerations, that will allow energy-efficient C-legged hexapod robots to be developed
It can be seen that the system power demand to the motor is not constant throughout one entire revolution

Summary

Introduction

The development and investigation of a large variety of mobile robots used in a wide diverse set of applications have been enhanced by electronics cost reduction, increased microchips computational capabilities, and intelligent and flexible manufacturing [1]. Wheeled robots have the ability to reach high speeds with low power consumption and can be guided by controlling few degrees of freedom, but their ability to overcome obstacles is limited [3] For this reason, wheeled robots are the most prominent, tracked and legged robots offer motion advantages over the former in unstructured environments [4,5]. It is important to recall that most parts of the earth and other planet’s surfaces are inaccessible to conventional wheeled robots, due to the uneven terrain and obstacles, and there is a need to develop new mobile robots with enhanced mobile capacities These natural terrains, on the other hand, offer a great opportunity for legged robots to demonstrate their terrain adapting capabilities [6]. The increased obstacle overcoming capabilities of legged robots can be explained by the fact that this type of robot does not require a continuous support surface, but uses a discrete foothold for each foot, enhancing their mobility [7]

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