Lateral undulation of the bendable body of a gecko-inspired robot for energy-efficient inclined surface climbing
Haomachai, W., Shao, D., Wang, W., Ji, A., Dai, Z., and Manoonpong, P.
IEEE Robotics and Automation Letters

Sprawling posture animals with their bendable spine, such as salamanders, and geckos, can perform agile and versatile locomotion including walking, swimming, and climbing. Therefore, several roboticists have used them as templates for robot designs to investigate and generate efficient locomotion. Typically, walking and/or swimming abilities are realized by salamander-inspired robots with a bendable body, whereas climbing ability is achieved on gecko-inspired robots with an over-simplified fixed body. In this study, we propose optimal bendable body design with three degrees of freedom (DOFs). Its implementation on a sprawling posture robot is inspired by geckos for climbing enhancement. The robot leg and body movements are coordinated and driven by central pattern generator (CPG)-based neural control. As a consequence, the robot can climb using a combination of trot gait and lateral undulation of the bendable body with a C-shaped standing wave. Through the real robot experiments on a 3D force measuring platform, we demonstrate that, due to the dynamics of the bendable body movement, the robot can gain higher medio–lateral ( Fx ) ground reaction forces (GRFs) at its front legs as well as anterior–posterior ( Fy ) GRFs at its hind legs to increase the bending angular momentum ( LAM ). This results in 52% and 54% reduced energy consumptions during climbing on steeper inclined solid and soft surfaces, respectively, compared to climbing with a fixed body. To this end, the study provides a basis for developing sprawling posture robots with a bendable body and neural control for energy-efficient inclined surface climbing with a possible extension towards agile and versatile locomotion, such as sprawling posture animals.


A Sprawling Posture Robot with a Flexible Spine for Efficient Locomotion in Various Gravity Environments from Earth, to Mars, and the Moon
Haomachai, W., Ngamkajornwiwat, P., Ji, A., Dai, Z., and Manoonpong, P.
In Innovation Aviation & Aerospace Industry – International Conference 2021

Low gravity is one of the most challenging considerations when designing robots for space exploration. Owing to the changing gravitational forces, the locomotion performance of a legged robot tends to decrease when gravity decreases. Recently, quadrupedal robots have been increasingly promoted for space exploration. Most existing studies have mainly developed robot locomotion with an erect posture and have focused on the use of leg functionality. However, to date, robot locomotion with a sprawling posture and a flexible spine has not been fully investigated. Therefore, herein we present a robot with a sprawling posture and flexible spine inspired by geckos for low-gravity locomotion enhancement. The gecko-inspired robot was constructed with a 3-DOF spine and 4-DOF legs. The movement of the robot was controlled using a central pattern generator (CPG). Physical simulations were performed under the gravitational conditions of Earth, Mar, and the Moon. The experimental results show that, owing to the lateral bending movement of the flexible spine with a C-shaped standing wave pattern, the locomotion speed of the robot is increased by 100% relative to that of a traditional fixed-spine robot under each gravity condition. Based on these results, a sprawling-type quadruped robot with a flexible spine will facilitate future studies on robot space exploration under low-gravity conditions.

An Artificial Hormone System for Adaptable Locomotion in a Sea Turtle-Inspired Robot
Haomachai, W., and Teerakittikul, P.
In 2019 4th International Conference on Control and Robotics Engineering (ICCRE)

There are various challenges to operate autonomous robots for a long time in outdoor real-world environments. One of the most challenging tasks is to reduce the cost of transport when locomoting over hard ground or uneven complex terrain. This paper proposes using an artificial hormone system as a mechanism which responds to external environmental changes and alters robot behaviours to move with energy efficiency. Specifically, hormone systems are used to help the robot deals with terrain variations. The emergence of adaptive locomotion focuses especially on the cost of transport usage. The proposed system is tested in real sea turtle-inspired robot and environment. The results have shown that the robot can adapt its gait and demonstrate robust locomotion which associates with reducing the cost of transport while traveling in complex environments.