时间：2022-08-18 08:17:06
A group of ants can move objects many times larger and heavier than themselves. This ability inspired a team of researchers to develop small robots that can do the same thing. The team created 29 millimeter long robots that can get a firm grip on the ground. In tests， six of the robots have just worked together to tow a full-size car.
They didn't move the car quickly. To haul it 12.5 centimeters took about one minute.
When ants carry a large item， such as a piece of food， they need good traction. To get a better grip， each ant presses its feet down harder. This increases the area of contact between each foot and the surface. Such ants served as the inspiration for David Christensen and his team of mechanical engineers at Stanford University California.
Ants can cling to a smooth wall or surface using small pads on their feet. When an ant puts its foot down， a tiny droplet of sticky gel oozes between the pad and wall. This holds the ant in place. When walking， only tiny bits of the ant's feet stick to the ground. That makes it easy for the ant to move quickly. The mechanical engineers wanted to create miniscule robots capable of moving big， heavy objects. But robots can't ooze liquid the way ants do. Using sticky gel wasn't an option for the tiny bots. So the researchers turned their attention to gecko feet.
The bottom of a gecko's foot has layers of tissue covered with tiny hairs. When the critter puts weight on the foot， those structures spread out. This increases contact between the foot and the surface to which the gecko clings. That contact allows van der Waals forces to hold the foot onto the surface. Van der Waals forces are tiny electrical attractions between molecules. By increasing the surface area between its foot and a leaf， wall or other object， the gecko uses enough van der Waals force to stay in place. Such stickiness is called adhesion.
微型机器人
蚁群能搬运体积和重量数倍于自身的物体。这种能力激发了某研究小组的灵感，他们开发了能像蚂蚁一样搬运数倍于自身体积和重量的物体的微型机器人。研究小组创造了29毫米长的机器人，这种机器人能够紧紧地附着在地面上。测试中，其中的6个机器人协同工作拖动了一辆实际大小的小轿车。
机器人没有快速搬动小轿车，而是用了大约1分钟时间把小轿车拖动了12.5厘米。
当蚁群搬运像一块食物这样的大物件时，需要有良好的附着摩擦力。为了更好地附着在地面，每一只蚂蚁必须更加用力将脚向下压，这样就增加了每一只脚与物体表面的接触面。美国加州斯坦福大学的戴维・克里斯滕森和他的机械工程师团队从蚁群身上获得了灵感。
蚂蚁用脚上小小的爪垫就能黏附在光滑的墙面或物体表面。当蚂蚁将脚压下时，在爪垫和墙面之间会慢慢渗出一小滴黏性的凝胶，帮助蚂蚁固定在合适的位置上。当蚂蚁走路时，仅有一小部分脚着地，这样使蚂蚁很容易快速走动。机械工程们想要创造能够搬动又大又重的物体的微型机器人，但是机器人不能够像蚂蚁那样渗出黏性液体，使用黏性凝胶不是解决微型机器人附着力问题的选择，所以，研究者们把他们的注意力转向了壁虎的脚。
壁虎的脚底有层层覆盖着微小毛发的组织，当壁虎向脚部施加重量时，这些组织结构就会伸展开来，这样能够增大脚和它所附表面的接触面积。这种接触所产生的范德瓦尔斯力使壁虎的脚能够牢牢地附着在物体表面。范德瓦尔斯力是分子间的极小的电性吸引力。通过增加脚和叶子、墙壁或者其他物体的接触面，壁虎能够用足够的范德瓦尔斯力使得自己附着在物体表面。这种黏性被称为黏附力。