| Three dimensional obstacle-free(TDOF) locomotion technology is one of the major directions in the future robotic development. It has important applications in the areas of search-and-rescue, space exploration, working in harmful environment, and military reconnaissance. Climbing on vertical and invert surfaces is the key technique in developing a TDOF robot. Most previous climbing robots are generally developed using suction cups, adhesives, and magnets. Considering the fact that most nature surfaces and some manmade materials, such concrete, and brick exterior surfaces, are rough, porous, and dusty, none of these approaches is suitable. Inspired by the animals which are capable of clinging on vertical surfaces, three novel adhesion methods, including dry adhesive, wet adhesive, and spine adhesion, have been developed for climbing robot design in recent years. However, current synthetic dry and wet adhesives only suite for clean and smooth surfaces. In nature, almost all insects employ claws/spines to climb on rough surfaces. In order to develop a robot which can climb on rough and dusty vertical surfaces, the research focuses on the design of spine-inspired wall-climbing robots and investigates their bio-inspired adhesion mechanisms.Firstly, the micro-morphology of claws and spines in insects are observed and measured, and a spine-surface interaction model as well as a spine gripper model has been developed to analyze the adhesion mechanism. Then, a bio-inspired spine mechanism has been developed, and is used to design the spine foot and spine gripper. Finally, three climbing robots have been developed to verify the spine mechanism. The climbing robots can achieve vertical and invert climbing on rough surfaces. It would provide the key technique and rationale basis for developing the three dimensional obstacle-free locomotion robots. The main research results and innovation in this thesis are as follows:(1) A spine/surface interaction model along with a griping model is developed tooptimize the parameters in the spine feet design.(2) Inspired by the flexible tarsal chain in insects’ foot, we have designed a flexiblespine mechanism. Different from the multi-material spine mechanism introducedby Stanford University, the one we proposed is the first single material spine mechanism achieved flexible properties by structure design. Compared with the advanced SDM (shape deposition manufacturing) technique (owned by a few organizations) used in fabricating the multi-material spine mechanism, the spine mechanism we proposed can be fabricated by mature SLS (selective laser sintering) rapid prototyping technique. In addition, the spine foot can be fabricated as one part to make the spine foot more compact, and the adhesion property is improved.(3) Combining the advanced features of spine adhesion and wheeled locomotion, a wheeled wall-climbing robot has been developed. A multi-spine/surface interaction model has been proposed to optimize the design parameters of robot, and the climbing experiments show that the climbing performance has been improved. The robot’s structure is simple with high mobility. It can make transition from horizontal to vertical surfaces, and the climbing speed on vertical brick surfaces is up to10cm/s.(4) Based on the bio-inspired flexible spine foot, a hybrid climbing robot driven by one motor has been developed. A modified Chebyshev four-bar linkage has been used to achieve the movement of insect’s leg by generating "D" shaped trajectory of foot. The spine is easy to cling on and retract from the wall surfaces. It is the first robot reported that can climb on both vertical hard surfaces (such as brick surfaces) and deformable surfaces (such as cloth curtain).(5) A bio-inspired spine gripper has been designed with extremely advanced adhesion capability, and the normal direction load can reach up to ten times of its dead weight. An inchworm-like bipedal robot has been developed with the spine gripper, and it is the first robot reported that can achieve climbing function on inverted rough surfaces with spine mechanisms. In addition, it can climb on vertical rough surfaces in any direction, and with transition ability between surfaces. |
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