Exoskeletons for running and walking

Abstract

An exoskeleton worn by a human user consisting of a rigid pelvic harness worn about the waist of the user and exoskeleton leg structures each of which extends downwardly alongside one of the human user's legs. The leg structures include hip, knee and ankle joints connected by adjustable length thigh and shin members. The hip joint that attaches the thigh structure to the pelvic harness includes a passive spring or an active actuator to assist in lifting the exoskeleton and said human user with respect to the ground surface upon which the user is walking and to propel the exoskeleton and human user forward. A controllable damper operatively arresting the movement of the knee joint at controllable times during the walking cycle, and spring located at the ankle and foot member stores and releases energy during walking.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a Non-Provisional of U.S. Patent Application Ser. No. 60 / 736,929 filed Nov. 15, 2006. [0002] This application is a continuation in part of U.S. patent application Ser. No. 11 / 395,448 entitled “Artificial human limbs and joints employing actuators, springs, and Variable-Damper Elements” filed on Mar. 31, 2006 by Hugh M. Herr, Daniel Joseph Paluska and Peter Dilworth. Application Ser. No. 11 / 395,448 claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60 / 666,876 filed on Mar. 31, 2005 and the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60 / 704,517 filed on Aug. 1, 2005. [0003] This application is also a continuation in part of U.S. patent application Ser. No. 11 / 499,853 entitled “Biomimetic motion and balance controllers for use in prosthetics, orthotics and robotics” filed on Aug. 4, 2006 by Hugh M. Herr, Andreas G. Hofmann and Marko B. Popovic. Applicatio...

AI Technical Summary

Benefits of technology

[0016] For the backpack load-carrying exoskeleton for walking, the system interfaces to the human by means of shoulder straps, a hip harness, thigh cuffs, and a shoe attachment. Natural walking kinematics are preserved by collocating the exoskeleton hip, knee, and ankle joints to their biological counterparts. A cam mechanism is implemented at the hip joint to project the exoskeleton hip center near the biological hip center. The cam mechanism corrects for discrepancies between the exoskeleton and biological leg lengths during abduction and adduction. Passive spring elements are implemented at the hip and ankle and a variable damper is implemented at the knee. A non-conservative actuator can add to the hip flexion spring output at the hip in order to add significant positive power during walking. Control systems are proposed to control the exoskeleton as a function of gait cycle both for knee variable-dampers and hip motor components.

[0017] For the human-carrying exoskeleton for running and jumping, a parallel leaf spring architecture is shown that stores energy during jumping and running to efficiently transfer the weight of the wearer to the ground. Simple force or contact sensing may be employed to activate a clutch or variable damper at the knee. To activate the exoskeleton knees passively, a weight activated knee unit may be used where the knee automatically locks upon knee compression loading and unlocks when compression forces are no longer borne by the knee unit. Additional elements may be included in the leg design, including a motor in parallel with the leg spring that stores additional energy into the leg spring to augment leg extension in jumping or stair / hill ascent.

[0018] The parallel spring and variable damping architectures presented here offer a number of advantages over other devices. Having the exoskeleton architecture in parallel with the human leg allows the stability of the wearer to be maintained. Springs in series with the human raise the center of mass of the wearer and thus destabilize the wearer. Springs in parallel can be disengaged to allow the human leg to swing freely in the swing phase. Also by allowing the wearer's foot to remain in contact with the ground, overall stability of the wearer is maintained.

Problems solved by technology

Difficulties in human sensing, stability of the servomechanisms, safety, power requirements and system complexity kept it from walking.

Pre-defined trajectories were commanded by the devices and they had limited success in assisting subjects to walk.

The devices were greatly limited by material, actuation and battery technology available at that time.

Such an exoskeleton design demands a great deal of power, requiring a heavy power supply to achieve system autonomy.

This approach leads to a noisy device that has a very low payload to system weight ratio.

Further, this type of exoskeleton is heavy, and if failure were to occur, could significantly harm the wearer.

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