高科技电子网球拍揭秘

    埃里克•百保力记得，1990年他在法国上大学时，曾经看过一部名叫《宇宙威龙》（Total Recall ）的电影。在这部电影中，莎朗•斯通和一个全息投影的“教练”一起打网球。当时埃里克不禁想到：“这就是网球的未来”。他可不是闲着没事才回想往事。埃里克•百保力是著名家族企业、法国网羽设备制造商百保力集团（Babolat）的第五代继承人，从他的曾曾祖父开始，百保力家族就已经在用羊肠线制做网球拍，制作原料来自法国里昂的屠宰场。百保力集团最近推出了一款名叫Babolat Play的网球拍。特别之处在于它是一副安装有电子设备的网球拍。

    百保力公司早在十年以前就提出了电子网球拍的理念，它觉得这样做可以收集更加可靠的数据用来开发原型产品。埃里克•百保力说：“我们有专业的测试人员测试一支网球拍是否太硬、太重或太轻了。我们希望所有测试人员都按照相同的标准测试，而且我们的工程师也想要捕捉详细的数据来进行研究。”后来他们很快发现，这项功能也会吸引网球运动员们的兴趣。“没有人具体知道球拍击中球的那一刻究竟发生了什么。”

    当时，这项技术还没有立即提上议事日程。到了三年前，这项技术似乎变得越来越吸引人，于是百保力集团又进行了一次尝试。这家公司重金聘请了总部位于法国格勒诺布尔市的运动感应技术公司Movea来研发这个系统。【2008年，Movea收购了曾与任天堂（Nintendo）合作研发Wii游戏机早期原型机的Gyration公司。】百保力集团专门提出了两个条件：第一，这个技术单元必须嵌入到网球拍的手柄内部，以免影响运动员比赛。第二，它的实用性必须针对所有运动员，而并不只是针对专业人士。

    研发团队开始在百保力最畅销的网球拍产品Pure Drive的基础上进行开发。Babolat Play和Pure Drive的重量相同，都是11盎司，外观看起来也一般无二。唯一显著的区别是Babolat Play的手柄底部有两个橙色亮条，以及用来激活球拍和通过蓝牙进行同步的按钮。

    打球之前，一定要记得打开球拍的开关——当然前提是别忘了充电。运动完毕后，你可以在电脑、平板或智能手机上通过一款应用登陆你的个人账户，下载你的数据。你在这里可以看到对运动数据的详细分类（正手、反手、发球、高压球），它还可以根据球拍的运行速度测算出你的击球力度，然后用百分比的形式显示出来（100%的力度大致相当于平击发球的速度达到每小时136英里）。另外它还能分析你经常使用的旋转球的种类和频率。球拍上安装的冲击定位器可以显示有多少比率的击球是击中了球拍的最佳击球点或其附近位置。Movea公司工程副总裁西里尔•索贝莱特表示，冲击定位器是整个产品研发过程中最难的部件，需要专门开发全新的技术。

    索贝莱特尽可能用简单的语言向我们解释了这款球拍的工作原理：运动时，手柄中的传感器会向负责运行算法的电子控制系统发送信号。有些分析运算会不间断地进行，比如球拍相对于地面的位置。其它的运算只是在击球的一瞬间才启动，就像车辆发生撞击时，气囊就会自动弹出一样。

    击球的瞬间，球拍短时内会在不同频率上经历好几种形式的弯曲、扭曲。电子控制系统会实时分析所有这些震动，在不到200毫秒的时间内，就会得出关于这次击球的大概20种不同性质的数据。同时它还可以自动识别、排除一些“无关动作”，比如在发球间隙将球弹来弹去时造成的震动，以及用球拍敲掉沾在球鞋上的土时造成的震动。

    索贝莱特表示，这项技术的精确度非常惊人，尽管有些东西目前它可能还无法测量到，比如说某次击球力度太大，将球打出界外甚至打到了停车场里。但是索贝莱特认为，最终随着其它工具的发展（比如在网球鞋里安装传感器），这个问题终究会得到解决。

    这项新技术最令人上瘾的地方是它含有电子游戏的因素在里面。每个运动员一开始都是一个“菜鸟”，然后可以像打游戏一样逐渐“升级”。坎里克•百保力说：“网球这项运动最令人沮丧的莫过于觉得自己没有进步。因此，在这款应用中加入一点激励的元素也就成了顺理成章的事。”你可以加入全球Babolat Play社区，然后查看自己的排名，把自己的表现和其他球员（甚至是纳达尔）进行对比。如果你对自己的进步满意的话，也可以把你的数据分享到Facebook上。

    这样一款电子球拍是否真能提高网球爱好者的技术？对此，埃里克•百保力说：“游戏元素的好处是，它能鼓励人们花更多的时间练习网球。看着自己的技术一天天提高，这种感觉很令人兴奋。”这家公司借给我一支球拍让我试用一两个星期。在它的提醒下，我注意到我的所有发球都太平了，于是我着重加了一些旋转进去，结果马上就看到了效果，而且无论是实地效果还是在应用上显示的效果都很明显。至于撞击定位器的功能，虽然我有相当一部分击球都正中甜点，但仍然有很大一部分击球点的位置偏低，于是我意识到是这是我的膝盖弯得不够造成的。但是用回我的旧球拍之后，我又有点松劲了。

    In 1990, when Eric Babolat was a college student in France, he remembers watching Sharon Stone play tennis with a hologram instructor in the movie Total Recall and thinking, "That's the future of tennis." This was not idle reflection. Babolat represents the fifth generation in a family business of tennis equipment makers, started when his great-great grandfather made the first strings out of sheep gut, obtained from the slaughterhouses of Lyon. Their latest innovation, a racquet called Babolat Play, has just come on the market. This time, it's not just strung; it's wired.

    The company first came up with the idea of a connected racquet a decade ago, thinking it would provide more reliable data about prototypes. "We have professional testers who analyze if a racquet is rigid, heavy, light," Babolat says. "We wanted to make sure that they were speaking the same language, and our engineers wanted captors to show exactly what was going on." They quickly realized this feature could prove interesting for players, too. "Nobody really knows what happens the moment the racquet hits the ball."

    At the time, the technology wasn't up to the task, but three years ago it looked more promising, and Babolat gave it another go. To develop the system, it hired Movea, a leader in motion sensing technology headquartered in Grenoble. (In 2008, Movea acquired Gyration, who had worked with Nintendo on an early prototype for the Wii.) Babolat established two conditions. First, the technology would have to fit inside the racquet handle so that it wouldn't affect a player's game. Second, it needed to be accessible and useful to all players, not just pros.

    They started by modifying the company's bestselling model, the Pure Drive. The Play version is the same weight, around 11 ounces, and looks nearly identical; the only obvious difference is two orange stripes at the bottom of the handle, buttons that activate the racquet and synchronize it via Bluetooth.

    You have to remember to switch the racquet on before playing -- and, prior to that, to charge it. Afterwards, you download the data to your user account on a computer, tablet or smartphone app. Here you can see a breakdown of your shots by number and classification (forehands, backhands, serves, smashes), the power of your strokes in percentage, based on the speed of the racquet (100 percent corresponds roughly to a flat serve of 136 miles per hour), the type of spin you use and how often. An impact locator shows what percentage of your shots hit the sweet spot or the areas around it. CyrilleSoubeyrat, vice president of engineering for Movea, says this was the most complicated feature to make, requiring the development of brand new technology.

    Soubeyrat did his best to explain in simple terms what happens inside the racquet during play. In the handle, sensors deliver signals to an electronic system, which executes algorithms. Some analysis takes place continuously, such as the racquet's position in relation to the ground. Other measurements start each time the ball hits the strings, setting off a reaction like when a car crash sets off an airbag.

    At the moment of impact, the racquet experiences several modes of flexion and torsion, and at different frequencies. The electronic system analyzes all of these vibrations simultaneously, and within 200 milliseconds produces information about 20 different properties of the shot. At the same time, it recognizes and rejects all the "parasitic" gestures, such as bouncing the ball between serves or using the racquet to whack clay off one's sneakers.

    Soubeyrat says the technology is remarkably accurate, even if there are things it cannot measure, like whether that ball you hit so powerfully went right over the court and into the parking lot. Eventually, he says, other tools could round out the offer, such as sensors in the shoes.

    One of the most addictive things about the new technology is the gaming aspect. Each player starts out as a "newbie" and can work his or her way up through levels like a video game. "There's nothing more frustrating in tennis than feeling you aren't progressing," Eric Babolat says. "To put a bit of reward in the application seemed like an obvious thing to do." You can join the global Babolat Play community, check your ranking and compare your performance to other players, even Rafael Nadal. If you like what you see you can share the data on Facebook.

    Can the racquet improve a player's technique? "The advantage of gaming is that it motivates people to play more tennis," Babolat says. "It's exciting to see how you evolve." The company lent me a Play for a couple of weeks to try out. After noting (to my chagrin) that all of my serves were flat, I concentrated on adding some spin and immediately saw the difference, on the court and on the app. As for the impact locator, I managed to hit the sweet spot a good part of the time, but also hit a sizable percentage below it, and realized that I wasn't bending my knees enough. Afterwards, going back to my old racquet was a bit of a letdown.