仿生可控粘附技术通过外场调控固-固界面的粘附作用，在智能抓取、物流转运、航空航天、柔性电子等领域具有广阔的应用前景。目前，仿生可控粘附技术在力学机理、表面制备、性能调控和技术应用等方面已经取得了诸多进展。然而，由于界面科学基础研究和抓取技术应用研究之间的跨度较大，目前报道的界面粘附调控设计方案仍然存在粘附面积小、法向负载低、适应能力差、响应速度慢、条件要求高等缺点。针对上述难题，本论文围绕仿生可控粘附设计在机器人抓取应用中的关键技术开展深入研究。针对微结构阵列粘附表面的粘附承载和剥离释放建立理论模型，计算并验证了结构几何和材料力学参数对剥离区域长度的影响规律，建立了强粘附易脱附的结构参数优化设计方法。揭示了承载能力和剥离区域长度的线性关系，其比例系数正比于等效粘附强度，而剥离区域长度与背部弯曲刚度和微柱拉伸刚度比值的1/4次方成正比。针对平面物体的高负载可控粘附设计，提出了三明治型可控粘附复合结构。通过钢片薄板抗拉伸和易弯曲特性调控界面应力分布和剥离区域大小从而实现可控粘脱附，设计了抓取平面物体的四足夹持器、倒置爬行的四足机器人和辅助人类攀爬的双盘夹持器，验证了150 cm2粘附面积和700 N承载能力的大面积高负载强粘附易脱附设计。针对曲面物体的自适应可控粘附设计，提出了基于软体驱动的可控粘附夹持器。设计了基于真空作用的背部承载结构，揭示了真空腔室通过改善粘附界面载荷均布增大剥离区域从而提高承载能力的机理。通过包覆、摩擦和粘附的协同作用实现了自适应抓取，搭建了非结构化环境抓取系统，验证了夹持器对于不同形状、尺寸、重量物体的自适应抓取能力。针对重型曲面物体的高负载和自适应抓取，设计了基于柔顺机构的双向弯曲可控抓取机构。该机构对多种曲面和平面具备适应性接触、高可靠承载和低强度脱附功能。单个抓取机构的抓取负载可达120 N，抓取物体表面曲率半径>0.1 m。基于多单元阵列协同策略，研制了一套50公斤级仿生粘附抓取系统，实现了对于50 kg重型曲面的动态抓取验证。
Biomimetic controllable adhesion technology, which modulates interfacial adhesion through external fields, has broad applications in fields such as intelligent grasping, transfer printing, aerospace technology, and flexible electronics. At present, much progress has been achieved in mechanical mechanism, surfaces synthesis, adhesion modulation, and technical application for biomimetic controllable adhesion technology. However, owing to the gap between the basic research of interface science and the application research of grasping technology, the proposed adhesion modulation strategies still face shortcomings such as small adhesion area, low normal load, poor adaptive ability, slow response speed, and high operation requirement. In order to address the above challenges, this paper focuses on the key technologies in the design and application of biomimetic controllable adhesion for robotic grasping systems. Theoretical models were established for the adhesive loading process and peel releasing process of bio-inspired micropatterned adhesive surfaces, respectively. The effects of structural and mechanical parameters on the peel zone length of bio-inspired micropatterned adhesive surfaces were calculated and validated. And an optimal design map was established for designing controllable adhesive grasping devices to achieve strong adhesion and easy detachment. The linear relationship between the loading capacity and the peel zone length was revealed, in which the linear coefficient is proportional to the effective adhesion strength of the adhesive layer while the peel zone length is proportional to the power of the ratio between the bending stiffness of the backing layer and the tensile stiffness of the adhesive micropillars. Aiming at the design of high-load controllable adhesion for planar objects, a sandwiched controllable adhesive composite structure was proposed. The controllable adhesion and detachment were realized by modulating interfacial stress distribution and peel zone through the anti-stretching and easy-bending properties of the steel sheet. A four-legged gripper capable of grasping flat objects, a quadruped robot able to crawl on the ceiling, and a double-disk gripper assisting human climbing were designed and developed, which demonstrated the design of large-area and high-load controllable adhesion in an adhesion area of 150 cm2 and a load capacity of 700 N.Aiming at the design of adaptive controllable adhesion for curved objects, a controllable adhesive gripper based on pneumatic soft actuators was proposed. A back loading mechanism based on vacuum effect was designed. The mechanism of enhancing loading capacity by improving the load sharing behavior of the adhesive interface to enlarge the peel zone via the vacuum chamber was revealed. By utilize wrapping, friction, and adhesion to realize adaptive grasping, an unstructured grasping system was built to demonstrate the multifunctional grasping ability of the soft adhesive gripper for objects with various shapes, sizes, and weights.Aiming at the high-load and adaptive grasping for heavy and curved objects, a bi-directional bending controllable grasping device based on compliant mechanism was designed, which can realize adaptive contact, reliable loading, and easy detachment for various curved and flat surfaces. The grasping load of a single device can reach over 120 N and the feasible object surface curvature radius is larger than 0.1 m. Moreover, based on a synergy strategy of multi-unit array design, a biomimetic adhesive grasping system with 50-kg loading capacity was developed, which was demonstrated to dynamically grasp and release a heavy and curved object with a mass of 50 kg.
