Measurement method of a microspring-supported force plate with an external laser displacement meter
Measurement method of a microspring-supported force plate with an external laser displacement meter
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DOI：
10.1088/1361-6501/ac7b12
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发表时间：
2022-10-01
影响因子：
2.4
通讯作者：
Takahashi, Hidetoshi
中科院分区：
文献类型：
--
作者：
Sugimoto, Takumi;Kawasaki, Yuta;Takahashi, Hidetoshi
地面反作用力（GRF）是评价动物运动能力的重要指标。最近，微力板已经被实现为微小昆虫的GRF测量方法。以前的微力板是高度敏感的，但脆弱和费力的制造，因为应变传感元件的使用。在这里，我们将高分辨率3D打印和非接触式位移计应用于果蝇的微力板。3D打印适用于更简单，可重复和复杂的三维制造，因此由板和四个支撑3D微弹簧组成的力板结构被开发为一个集成单元。当果蝇落在平板表面时，通过检测平板中心的外部位移，由弹簧常数计算出整个装置的垂直GRF。由于支撑3D微弹簧，测力板足够坚韧。微弹簧的弹簧常数设计为约5.98 N m（-1），这使得高分辨率的外部激光位移计能够实现小于果蝇体重的1/50的力分辨率。假设四个弹簧具有相同的弹簧常数，并且位移计在板中心对齐，原则上，从位移转换为力时不存在位置误差。然而，制造误差确实会导致弹簧常数的差异。这里，我们从理论上和实验上确定了位移传感器的测量点，其中补偿了由四个微弹簧的弹簧常数的差异引起的位置误差。在实验中证实，校准过程将位置误差改善到+/-1.5%以内。最后，我们演示了果蝇的GRF测量。平均GRF为6.5 μ N，相当于一只果蝇的重量。我们提出的设备可以帮助评估微小昆虫的生物力学。
Ground reaction force (GRF) is a significant factor for the evaluation of animal locomotion. Recently, micro force plates have been implemented as a GRF measurement method for tiny insects. Previous micro force plates were highly sensitive, but fragile and laborious to fabricate, because of the use of strain-sensing elements. Here, we applied high-resolution 3D printing and a noncontact displacement meter to a micro force plate for a fruit fly. 3D printing is suitable for easier, reproducible, and complex three-dimensional fabrication so that a force plate structure, which consists of a plate and four supporting 3D microsprings, is developed as an integrated unit. By detecting the displacement of the plate centre externally, when a fruit fly lands on the plate surface, the vertical GRF of the whole device is calculated via the spring constant. The force plate is sufficiently tough due to the supporting 3D microsprings. The spring constant of the microspring is designed to be approximately 5.98 N m(-1), which enables a high-resolution external laser displacement meter to realize a force resolution of less than 1/50 of the body weight of a fruit fly. Providing that the four springs have the same spring constant and the displacement meter aligns at the plate centre, in principle, there is no positional error when converting from displacement to force. However, fabrication error does lead to spring constant differences. Here, we theoretically and experimentally determined the measurement point of the displacement sensor where the positional error caused by the difference in the spring constant of the four microsprings is compensated for. It was confirmed in the experiment that the calibration process improved the position error to be within +/- 1.5%. Finally, we demonstrated the GRF measurement of a fruit fly. The average GRF was 6.5 mu N, which was equal to the weight of a fruit fly. Our proposed device can help evaluate the biomechanics of tiny insects.