Unlike passive artificial legs, robotic legs have the capability of moving independently and out of sync with its users movements. So the development of a system that integrates the movement of the prosthesis with the movement of the user is "substantially more important with a robotic leg," according to the authors.
Not only must this control system coordinate the actions of the prosthesis within an activity, such as walking, but it must also recognize a user's intent to change from one activity to another, such as moving from walking to stair climbing.
Identifying the user's intent requires some connection with the central nervous system. Currently, there are several different approaches to establishing this connection that vary greatly in invasiveness. The least invasive method uses physical sensors that divine the user's intent from his or her body language. Another method the electromyography interface uses electrodes implanted into the user's leg muscles. The most invasive techniques involve implanting electrodes directly into a patient's peripheral nerves or directly into his or her brain. The jury is still out on which of these approaches will prove to be best. "Approaches that entail a greater degree of invasiveness must obviously justify the invasiveness with substantial functional advantage," the article states.
There are a number of potential advantages of bionic legs, the authors point out.
Studies have shown that users equipped with the lower-limb prostheses with powered knee and heel joints naturally walk faster with decreased hip effort while expending less energy than when they are using passive prostheses.
In addition, amputees using conventional artificial legs experience falls th
|Contact: David Salisbury|