Winand Julian, Büscher Thies H, Gorb Stanislav N
Department of Functional Morphology and Biomechanics, Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Biomimetics (Basel). 2024 Feb 26;9(3):142. doi: 10.3390/biomimetics9030142.
Gripping, holding, and moving objects are among the main functional purposes of robots. Ever since automation first took hold in society, optimizing these functions has been of high priority, and a multitude of approaches has been taken to enable cheaper, more reliable, and more versatile gripping. Attempts are ongoing to reduce grippers' weight, energy consumption, and production and maintenance costs while simultaneously improving their reliability, the range of eligible objects, working loads, and environmental independence. While the upper bounds of precision and flexibility have been pushed to an impressive level, the corresponding solutions are often dependent on support systems (e.g., sophisticated sensors and complex actuation machinery), advanced control paradigms (e.g., artificial intelligence and machine learning), and typically require more maintenance owed to their complexity, also increasing their cost. These factors make them unsuited for more modest applications, where moderate to semi-high performance is desired, but simplicity is required. In this paper, we attempt to highlight the potential of the tarsal chain principle on the example of a prototype biomimetic gripping device called the TriTrap gripper, inspired by the eponymous tarsal chain of insects. Insects possess a rigid exoskeleton that receives mobility due to several joints and internally attaching muscles. The tarsus (foot) itself does not contain any major intrinsic muscles but is moved by an extrinsically pulled tendon. Just like its biological counterpart, the TriTrap gripping device utilizes strongly underactuated digits that perform their function using morphological encoding and passive conformation, resulting in a gripper that is versatile, robust, and low cost. Its gripping performance was tested on a variety of everyday objects, each of which represented different size, weight, and shape categories. The TriTrap gripper was able to securely hold most of the tested objects in place while they were lifted, rotated, and transported without further optimization. These results show that the insect tarsus selected approach is viable and warrants further development, particularly in the direction of interface optimization. As such, the main goal of the TriTrap gripper, which was to showcase the tarsal chain principle as a viable approach to gripping in general, was achieved.
抓取、握持和移动物体是机器人的主要功能用途。自自动化首次在社会中扎根以来，优化这些功能一直是高度优先事项，人们采取了多种方法来实现更便宜、更可靠和更通用的抓取。目前正在努力减轻抓取器的重量、能耗以及生产和维护成本，同时提高其可靠性、适用物体范围、工作负载和环境适应性。虽然精度和灵活性的上限已被提升到令人印象深刻的水平，但相应的解决方案通常依赖于支持系统（如精密传感器和复杂的驱动机械）、先进的控制范式（如人工智能和机器学习），并且由于其复杂性通常需要更多维护，这也增加了成本。这些因素使其不适用于更普通的应用，在这些应用中，需要中等至半高性能，但要求简单。在本文中，我们试图以一种名为TriTrap抓取器的仿生抓取装置原型为例，突出跗骨链原理的潜力，该原型受昆虫同名跗骨链的启发。昆虫拥有坚硬的外骨骼，通过多个关节和内部附着的肌肉实现活动。跗骨（脚）本身不包含任何主要的内在肌肉，而是由外部拉动的肌腱驱动。就像其生物学对应物一样，TriTrap抓取装置利用强烈欠驱动的手指，通过形态编码和被动构象来执行其功能，从而形成一种通用、坚固且低成本的抓取器。它在各种日常物体上测试了抓取性能，每个物体代表不同的尺寸、重量和形状类别。TriTrap抓取器能够在提起、旋转和运输时将大多数测试物体安全地固定到位，无需进一步优化。这些结果表明，所选择的昆虫跗骨方法是可行的，值得进一步开发，特别是在接口优化方向。因此，TriTrap抓取器的主要目标，即展示跗骨链原理作为一种通用的可行抓取方法，得以实现。
