Millions of people have conditions that make walking difficult. Millions more regularly perform tough movement as part of their jobs. Wearable robotic devices called exoskeletons that help the legs move could benefit both of these groups. In laboratory settings, such devices have helped people walk faster while using less energy. But various obstacles have kept these devices from being practical for everyday use.

A research team at Stanford University led by Dr. Steven Collins has developed an exoskeleton that can rapidly adapt to the user during normal walking. The team tested how well an exoskeleton based on their model could adapt to a user. They then compared it to one based on lab measurements. Both methods wound up applying similar forces at different speeds and reduced effort similarly across a range of conditions. But the model-based adaptation took only one-quarter as long as the measurement-based adaptation.

Next, the researchers created a portable, ankle-worn exoskeleton that could be used in the real world. The exoskeleton was powered by a battery pack worn at the waist.

The team conducted tests of the device outdoors on public sidewalks. Compared with walking in normal shoes, the exoskeleton increased walking speed by 9% while expending 17% less energy on average. This is equal to the energy savings of removing a 20-pound backpack. When walking on a treadmill (跑步机) at a constant speed, users expended up to 23% less energy, equal to removing a 30-pound backpack.

“This exoskeleton personalize s assistance as people walk normally through the real world,” Collins says. “This opens the door to a much broader use of exoskeletons to assist individuals with physical impairments (损伤) and people who need to carry heavy loads,” adds co-author Dr. Scott Delp.

【小题1】Who are exoskeletons designed for?

A．Sportsmen in a race.	B．Firefighters on a mission.
C．Patients with mental disabilities.	D．Doctors doing an operation.

【小题2】What do the underlined word “obstacles” in the first paragraph mean?

A．Barriers.

B．Applications.

C．Models.

D．Backpacks.

【小题3】Why are the figures listed in paragraph 4?

A．To illustrate the advantage of exoskeletons.	B．To compare exoskeletons with normal shoes.
C．To give examples of different kinds of shoes.	D．To list the reasons for designing exoskeletons.

【小题4】What’s Dr. Scott Delp’s attitude towards exoskeletons?

A．Conservative.

B．Negative.

C．Favourable.

D．Indifferent.