3D mannequin helps cyclist go for gold

By printing a 3D mannequin of leading international cyclist Tom Dumoulin and testing a series of skinsuits on his replica inside a wind tunnel until they found the perfect fit, researchers-at-tu-delft-believe-they-can-help-team-giant-alpecin-win-gold-at-the-uci-road-world-championships">researchers at TU Delft believe they can help Team Giant-Alpecin win gold at the UCI Road World Championships in Doha.

Olympic silver medalist Tom Dumoulin is confident of winning a gold medal in the men's time trial at the UCI (Union Cycliste Internationale) Road World Championships in Doha on October 12 - and the leading cyclist has a secret weapon.

A skinsuit worn by the Dutchman was developed by researchers at Delft University of Technology (TU Delft), in conjunction with his team, Team Giant-Alpecin, using an unusual technique.

The inter-disciplinary team from TU Delft scanned Dumoulin's body using photogrammetry, before 3D printing a full-sized replica mannequin of his body in classic riding posture. The mannequin was then dressed in a series of skinsuits made of various fabrics and placed on his bicycle saddle, where it underwent tests in the university's wind tunnel.

Dr Jouke Verlinden, of TU Delft's Faculty of Industrial Design Engineering, led the development of the mannequin, which first involved placing 150 DSLR cameras in a room and programming them to each simultaneously take a single image of Dumoulin sitting absolutely still on the cycle.

Verlinden told Reuters: "You really want to have someone like that fixed in the right position and you need to have an instant 3D scan of that. We used a system based on photogrammetry, so taking a lot of pictures with a high-resolution camera, an SLR camera, and we had a rig with 150 of these cameras which took one picture completely at the same time, and from that we could reconstruct a 3D model."

The mannequin was constructed using an inexpensive 3D printing method. This consisted of turning two household 3D printing machines on their head, so they could print up to two meters high, producing Dumoulin's replica in eight separate parts. It took a total of 50 hours to print, before each part was attached via simple pin-and-hole joints.

"It (the printer) uses plastic wire, which is extruded like a glue gun and then it's being drawn on the flat surface below, at a tenth of a millimeter or less, and in that way layer by layer you draw these kind of plastic curves," explained Verlinden.

The suit was originally made for Dumoulin's participation in this summer's Tour de France and Olympic Games in Rio. Speaking before the two events, he explained his hopes for the skinsuit. "In cycling, and especially in time trialling, it's about seconds, and even if we get only a little difference with a faster suit it will make a big difference maybe in the result," he said.

Unfortunately, an accident meant Dumoulin had to withdraw from the Tour at stage 19, but his Olympic performance was a happier experience, with him finishing second in the time trial behind Fabian Cancellara.

Andrea Sciacchitano, assistant professor in aerospace at TU Delft, told Reuters that aerodynamics is crucial to time trial performance.

"In order to go faster aerodynamics is very important, it's up to 90 percent of the total resistance that the guy has to overcome - and the roughness of the fabric is very important in order to reduce drag," he said. "One may think that in order to go faster the surface must be very smooth. This is, in fact, not always the case. In some cases some roughness can help the guy to go faster because it energizes the flow close to the surface. So it allows the flow to close on the back and therefore to reduce the aerodynamic drag."

Sciacchitano said a technique developed at the university called particle image velocimetry (PIV) proved crucial in the wind tunnel tests. Helium-filled soap bubbles were used to map the flow and ensure good measurements.

"In the wind tunnel we can have a very controlled environment, very specific flow velocity. Particle Image Velocimetry, is a particular technique that we have developed at TU Delft, in which we introduce small particles in the flow, we illuminate them by means of a laser and we take images of these particles - and by measuring the displacement of these particles at two time instance we can determine the velocity field and therefore the pressure and finally the aerodynamic drag," he said.

Dr Daan Bregman, of the TU Delft Sports Engineering Institute, said the same techniques could be used to test other parts of Dumoulin's equipment.

"We want to use this mannequin to test more aspects of his aerodynamics," said Bregman. "For example, which helmet should we use, can we use the same time trial suit when it's raining or maybe we should use something else. So it gives us loads of opportunities to test all the things we want without having Tom Dumoulin here in the wind tunnel."

Bregman added that the project's multidisciplinary nature had been of enormous benefit to the project.

Teun van Erp, the scientific consultant for Team Giant-Alpecin, was involved in the testing program, and is hopeful the innovative skinsuit could help Dumoulin win gold in Doha. "We hope that with ten or fifteen seconds extra gain we have with the suit he will win the gold medal," he said.

Van Erp added that five of Dumoulin's colleagues in Team Giant-Alpecin will also be wearing tailor-made suits in Qatar, developed using the 3D mannequin tests.

The TU Delft team believes similar tests could be conducted on suits worn by speedskaters and swimmers, where drag is also an important element of sporting performance.

译文：

通过印刷的三维人体模型主要国际自行车汤姆Dumoulin和测试一系列的紧身衣在他的副本在一个风洞,直到他们发现完美的配合,researchers-at-tu-delft-believe-they-can-help-team-giant-alpecin-win-gold-at-the-uci-road-world-championships " >荷兰代尔夫特科技研究人员相信他们可以帮助团队Giant-Alpecin赢得金牌在UCI路世界锦标赛在多哈。

奥运银牌得主汤姆Dumoulin有信心赢得金牌的男子在UCI的计时赛(联盟抗议声)路世界锦标赛在多哈10月12日,领先的自行车有一个秘密武器。

荷兰人所穿的紧身衣是由研究人员在代尔夫特理工大学(荷兰代尔夫特科技),与他的团队,团队Giant-Alpecin,使用一种不寻常的方法。

跨学科团队来自荷兰代尔夫特科技扫描Dumoulin的身体使用摄影测量,在3 d打印一个全尺寸的复制品的人体模特在经典骑他的身体姿势。人体模型当时穿着紧身衣的一系列各种面料和放在他的自行车鞍座,在经历了大学的风洞测试。

博士Jouke Verlinden,代尔夫特理工大学学院工业设计工程、led的发展模型,首先把150单反相机在一个房间里,编程每个同时采取单一的形象Dumoulin坐在绝对还在循环。

Verlinden告诉路透:“你真的想有人这样固定在正确的位置,你需要有一个即时3 d扫描。我们使用基于摄影测量的系统,所以拍摄很多照片与高分辨率相机,单反相机,和我们有一个钻井平台150个摄像头了一幅完全在同一时间,从那我们可以重建三维模型。”

人体模型是使用一个便宜的3 d打印方法构造。这包括将两个家庭3 d打印机器在他们的头上,这样他们就可以打印两米高,生产Dumoulin复制品的八个独立的部分。共有50个小时才打印,每一部分之前通过简单pin-and-hole关节连接。

“这(打印机)使用塑料线,这是挤压像喷胶枪,然后它被画在下面的平面,在十分之一毫米或更少,这样一层一层地你画这类塑料曲线,“Verlinden解释道。

诉讼最初为Dumoulin参与今年夏天的环法自行车赛,在里约热内卢奥运会。在两起事件之前,他解释说他希望的紧身衣。骑自行车”,尤其是在时间的尝试,它是秒,即使我们得到更快的一点点区别与西装会产生很大的不同也许在结果,”他说。

不幸的是,事故意味着Dumoulin 19不得不退出旅游阶段,但他的奥运表现快乐的体验,与他完成第二次审判费边Cancellara后面。

助理教授安德里亚Sciacchitano在荷兰代尔夫特科技宇航,告诉路透,空气动力学对时间试验性能是至关重要的。

“为了更快空气动力学是非常重要的,它是90%的人必须克服的总电阻,粗糙的织物是非常重要的,以减少阻力,”他说。”一位可能会认为,为了更快的表面一定很顺利。这是,事实上,并非总是如此。在某些情况下一些粗糙度可以帮助他更快,因为它激发流接近水面。所以它允许流关闭背面,因此降低气动阻力。”

Sciacchitano说大学开发的技术称为粒子图像测速技术(PIV)风洞试验证明至关重要。充满氦气肥皂泡被用来映射流和确保良好的测量。

“风洞中我们可以有一个可控的环境,非常具体的流速。粒子图像测速技术显现的是一个特定的技术,我们开发了在荷兰代尔夫特科技,我们引入流中的小颗粒,我们通过激光照射,我们把这些粒子的图像,通过测量这些粒子的位移两次实例我们可以确定压力和速度场,因此最后气动阻力,”他说。

她女儿师博士你代尔夫特体育工程学院,说同样的技术也被用来测试的其他部分Dumoulin的设备。

“我们想用这个模型来测试更多的空气动力学方面,“师说。头盔应该用“例如,我们可以使用相同的时间试验适合当下雨或者也许我们应该使用别的东西。所以它给我们提供了大量的机会来测试所有我们想要的东西没有汤姆Dumoulin在风洞”。

师还说,项目的多学科性质被巨大的福利项目。

Teun van Erp,Giant-Alpecin科学顾问团队,参与测试的项目,希望创新紧身衣可以帮助Dumoulin赢得金牌在多哈。“我们希望十或十五秒额外增加我们与诉讼他将赢得金牌,”他说。

范Erp补充说,在团队Giant-Alpecin Dumoulin的五个同事也将在卡塔尔穿定制西装,使用三维人体模型开发的测试。

荷兰代尔夫特科技团队认为可以进行类似的测试所穿的西装speedskaters和游泳,在拖动运动性能也是一个重要的元素。