A compliant constant-force mechanism is a passive force regulation device that can generate a nearly constant output force over a range of input or output displacements while without the use of sensors and feedback control. In topology synthesis of a compliant constant-force mechanism for a given input displacement range, the constant output force can be achieved by maintaining the output displacement to be nearly a same value while the input displacement increases. In order to further control the desired output displacement for the compliant constant-force mechanism before contacting the object, this article introduces a new composite objective function that can consider both the output force (with contact) and the output displacement (without contact) of the synthesized compliant mechanism. The sensitivity for the proposed objective function with respect to the element density is derived while considering the effect of nonlinearity in the large deformation condition. The proposed topology optimization method is used to design an innovative constant-force compliant finger, and its prototype is manufactured by 3-D printing using a flexible thermoplastic elastomer. The experimental results show the developed constant-force compliant finger can provide a nearly constant output force of 41.9 N over the input displacement ranging from 15 to 30 mm while the maximum and average force variations within the constant-force range are 2.2% and 0.9%, respectively. In addition, the developed constant-force compliant finger is used to design a three-fingered constant-force compliant gripper that can be used in robotic grasping of fragile objects.

中文翻译：

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3D 打印恒力手指设计的拓扑优化


柔顺恒力机构是一种被动力调节装置，可以在一定范围的输入或输出位移范围内产生几乎恒定的输出力，同时无需使用传感器和反馈控制。在给定输入位移范围的柔顺恒力机构的拓扑综合中，可以通过在输入位移增加时保持输出位移几乎相同的值来实现恒定的输出力。为了进一步控制柔顺恒力机构在接触物体之前所需的输出位移，本文引入了一种新的复合目标函数，该目标函数可以同时考虑物体的输出力（有接触）和输出位移（无接触）。综合顺应机制。在考虑大变形条件下非线性的影响的同时，导出了所提出的目标函数对单元密度的敏感性。所提出的拓扑优化方法用于设计创新的恒力柔性手指，其原型是使用柔性热塑性弹性体通过 3D 打印制造的。实验结果表明，所开发的恒力柔性手指可以在15至30 mm的输入位移范围内提供41.9 N的近乎恒定的输出力，而恒力范围内的最大和平均力变化分别为2.2%和0.9% ， 分别。此外，所开发的恒力柔性手指用于设计三指恒力柔性抓手，可用于机器人抓取易碎物体。