With extraordinary ease
A person is able to move at different speeds, starting with a leisurely gait and ending with running for the sake of saving life. As a rule, we choose the method of movement that allows us to consume the least amount of energy at the required speed. For example, with equally slow movement, the metabolic rate when walking is lower than when running; and with fast movement, on the contrary, the metabolic costs of running are lower than walking.
Researchers have previously developed robotic devices for rehabilitation and applications in other areas of life that help walking or running, but no portable device can effectively cope with both tasks. Facilitating walking and running with the same device is a problem due to fundamentally different biomechanics. Nevertheless, both walking and running begin with a general extension of the hip joint, which begins around the time when the foot comes into contact with the surface, and requires considerable effort to move the body forward.
The use of an auxiliary suit in various conditions: the robotic device detects the shift of the center of gravity during walking and running and quickly adjusts to the movement. Source here and further: Wyss Institute at Harvard University.
A group of researchers from the Wyss Institute of Harvard University and the School of Engineering and Applied Sciences. John A. Paulson and the University of Nebraska at Omaha have developed a portable exo-suit that helps to move around, taking into account the specific features of movement in the hip joint when walking and running. This lightweight suit is made of textile components that are attached to the waist and hips, and has a movable executive system fixed to the lower back, which is controlled by an algorithm that accurately determines the transition from walking to running and vice versa.
The group demonstrated that when exercising on a treadmill, the suit on average reduces the metabolic costs of walking by 9.3% and running by 4%. The device worked equally well during the uphill climb, at different running speeds and during outdoor tests, proving the versatility of the system.
The new exo-suit is intentionally made simpler than the previous versions, which were fixed not only to the hip, but also to the ankle joint. It is powered by a system of straps that creates a stretching force between the waist and hip belts in order to obtain external torque in the hip joint, which works in conjunction with the gluteal muscles. The device weighs only 5 kg, while more than 90% of its weight is located near the center of gravity of the body. This approach to weight concentration combined with a flexible clothing interface minimizes the energy load and movement restriction for the user.
The main task that needed to be solved was the ability of the exo-suit to distinguish between walking and running and, accordingly, to change the required amount of assistance provided during certain gait cycles.
During walking, the center of gravity of the body rises after the heel support, then reaches its maximum height in the middle of the movement phase and falls towards the end of the movement phase. When running, the movement of the center of gravity is opposite. It descends to the minimum height in the middle of the movement phase and then rises upwards in the direction of repulsion.
Using the described biomechanical features, the authors have developed a gait classification algorithm based on the biomechanics of the musculoskeletal system, which can reliably and accurately detect the transition from one gait to another by tracking the movement of a person's center of gravity using sensors attached to the body. As soon as a change in gait is detected, the exo-suit automatically adjusts the timing of its algorithm to help the other gait, reducing the body's oxygen consumption.
The researchers further plan to optimize all aspects of the technology, including reducing the weight of the device, individual algorithms for each user and simplification of use. The device will be useful for people with gait disorders, workers in industries at risk of injury, performing physically strenuous work, and the military.
Article by J. Kim et al. Reducing the metabolic rate of walking and running with a versatile, portable exosuit is published in the journal Science.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru according to the materials of the Wyss Institute: Suit up with a robot to walk AND run more easily.