Learning to walk the first time around is cute and easy. Having to relearn this basic skill due to a stroke, brain injury, Parkinson's disease, or Multiple Sclerosis is another matter. Thanks to the AutoAmbulator system from HealthSouth Corp., Birmingham, Ala., rehabilitation therapy is now easier than ever for patients and the physical therapists who teach them how to walk again.

One type of physical therapy for individuals who have lost the use of their legs is known as "body weight supported treadmill training." Patients are held up by therapists who manually move their legs across the treadmill. The system is labor-intensive and expensive, and does not produce smooth and coordinated movement. Furthermore, patients often are hindered by the fear of falling, and therapists are limited by the exertion needed to physically support the patients.

HealthSouth Corp. wanted a therapy tool that would alleviate the physical stress for the therapists, give the patient a safe and effective therapy session, and conserve space in their rehabilitation facilities. Gary West, director of engineering, addressed these concerns by designing the AutoAmbulator. The machine employs a harness to hold a patient in an upright position while robotic braces move the patient's legs across a treadmill. Early prototypes of the system were designed with the motion control independent from the central machine controller, hindering communication, programmability, and flexibility.

Rockwell Automation teamed with West to enhance the AutoAmbulator with Allen-Bradley Kinetix Integrated Motion, a system consisting of ControlLogix programmable controllers, servo drives, servomotors, and actuators. Controlled and synchronized robotic legs allow patients to use normal gait patterns and participate in the movement, but rely on the system for the remaining force that is necessary to generate the motion. Sensors monitor and adjust power and speed according to each patient's condition. The machine design also allows therapists to adjust the weight bearing and walking speed for each patient. .

The AutoAmbulator also includes safety features that automatically stop the machine when an adverse event occurs, such as a severe spasm or if the patient's foot improperly strikes the treadmill. Photoelectric sensors monitor torque through the motors and gearboxes to determine if the patient's legs exceed the recommended force.

The objective of gait training is to reestablish a natural walking pattern. A typical 30-minute therapy session using the traditional method might produce 20 to 30 steps, but never effectively retrains a patient's brain to move their legs in a way that is natural and consistent. The AutoAmbulator system helps patients walk more than a thousand feet and take several hundred steps in one session.

For more information, visit Rockwell Automation.