Patent Application
20160158593
Not applicable
Not Applicable
1. Field of the Invention
The present invention pertains to the field of physical exercise equipment. More specifically, the invention comprises an exoskeleton-based device that can apply force to the body in a controlled manner. Among other things, the invention is useful for simulating the forces produced by gravity in a weightless environment.
2. Description of the Related Art
Extended weightlessness causes bone loss and other undesirable effects on the human body. Since the body's structures are not used for support and balance, muscle mass tends to be lost over time and the bones tend to become less dense. This problem has been recognized for decades. Mission planners have long realized that human beings staying in space for an extended period need exercise devices. Designing such devices is difficult, since reaction forces must be countered in order to keep the astronaut in one place.
NASA's Skylab space station included a stationary exercise bicycle. It also included a “treadmill” where bungee cords were attached to a backpack-style harness positioned to urge the astronaut toward a flat walking surface with a force of 80 kg. A TEFLON sheet was placed on the walking surface and the astronaut “walked” on the sheet by sliding his feet in a walking motion.
Space Shuttle missions employed a bungee treadmill and a cycle exercise device as well. In addition, the Space Shuttle added a zero-g rowing machine to the devices developed for Skylab. The International Space Station has employed similar devices, with a few additional strength-training devices being developed as well.
Weight is a critical factor in any hardware intended for use in space. Another important factor is the space consumed by the device. Stationary devices were used in Skylab and these were left assembled when not in use. Skylab was relatively roomy, however. Future missions likely will not have the luxury of a dedicated exercise area.
In addition, it is often difficult for an astronaut to dedicate a large block of time purely to exercise. Human beings on earth are constantly using their muscles and connective structures to move and balance under the pull of gravity. Balance and movement require little conscious thought. Thus, a human being on earth often moves and balances while performing other complex tasks.
It would be advantageous tor an astronaut in zero-g to be able to exercise while performing other functional tasks. In order to achieve this goal an exercise device should be portable so that the astronaut is free to move around. The exercise device should preferably also be fairly compact so that it does not interfere with other activity. Finally, it is preferable for the exercise device to perform multiple different functions.
The present invention comprises a wearable robotic device configured to provide exercise for a human user. A primary use of the device is to address muscle and bone density loss for astronauts spending extended periods in microgravity. In one configuration the device applies a compressive force between a user's feet and torso. This force acts very generally like gravity—forcing the user to exert a reactive force. The compressive force is precisely controlled using a processor running software so that a virtually endless variety of force applications are possible. For example, the wearable device can be configured to apply a gravity-simulating force throughout the device's range of motion.
The robotic device may also be configurable for non-wearable uses. In these cases the robotic device may act as an exercise machine. The programmable nature of the force application allows the device to simulate weight-training devices and other useful exercise devices. The device's functions may be implemented in a microgravity environment or a normal terrestrial environment.
Lower frame 32 is attached to cradle 34 and thereby to user 10. The lower frame mounts a pair of exoskeleton “legs,” each of which is connected to a foot plate 28. Each exoskeleton leg includes an upper link 24 and a lower link 26. Upper link 26 is pivotally connected to lower frame 32 at hip joint 16. In this embodiment hip joint 16 is a simple pivot joint. It is not powered in this embodiment and is instead free to rotate with minimal friction. Likewise, in the embodiment shown, ankle joint 20 is a simple, unpowered pivot joint.
Lower link 26 is pivotally connected to upper link 24 via knee joint 18. Knee joint 18 is contained within actuator housing 22. An actuator or actuators within this housing is configured to control the position of knee joint 18 and the amount of torque applied to the knee joint. The robotic knee joints are capable of high-fidelity torque control. Power for the joints may be provided by an external cable or by energy storage devices mounted on or in the exoskeleton itself.
The effect of the powered knee joint 18 is that the exoskeleton can apply a wide variety of forces between hip joint 16 and ankle joint 20. The forces applied at ankle joints 20 are transferred to the user's feet 14 through foot plates 28. The forces applied at hip joints 16 are transferred to the user's torso 12 via the “backpack”-type harness the user wears (cradle, waist strap, shoulder straps, etc.).
The applied forces may be used among other things to (1) simulate the compressive farce of gravity in a static position; (2) provide resistance to movement during exercise; and (3) provide a constant load during exercise to simulate the effect of gravity.
The reader will note that the joints of the inventive exoskeleton are not aligned with the user's corresponding joints. In some rare instances there may in fact be alignment—depending on the user's anatomy—but joint alignment is not necessary or even desirable for the proper use of the inventive exoskeleton. In
The exoskeleton may be worn while performing a wide variety of movements.
Those skilled in the art will know that many different types of torso harnesses are known. The version shown should properly be viewed as one example among many possibilities. It is preferable to provide snap-fitting attachments between the harness components. It is also preferable to provide easy length-adjustment features on the straps. Many components may be selected to provide this functionality.
The primary purpose of the harness is to transmit loads from the user's torso to the exoskeleton. The reader will note in
The ankle joints are preferably only capable of rotation about a single axis. This feature assures that compressive forces are applied evenly to the sole of the foot. If the robotic legs are urging the foot plates 28 upward in the view of
On the other hand, the presence of the ankle joints allows the user's feet to move in flexion and extension. The user may pivot the foot plates about the ankle joints in order to move the feet in flexion and extension.
The reader will thereby appreciate the functionality of the inventive exoskeleton. The device is particularly useful in the microgravity environment. The user may employ the device to simulate the effects of gravity while performing a variety of exercises—such as squats. In addition, the device may be used to maintain muscle and bone mass while performing other activities. In a microgravity environment, a user often “floats” while performing tasks. The inventive exoskeleton may be worn while performing these tasks. The exoskeleton may be programmed to apply gravity-simulating loads that the user must counteract. The user will become accustomed to the muscular effort required to counteract these forces and it will become second nature—much as standing in a balanced position is second nature. Thus, the user may continue performing tasks without giving any conscious thought to the function of the exoskeleton. However, the exoskeleton is forcing the user to employ his or her body to counteract the forces and thereby maintain muscle mass and bone density.
Some embodiments of the invention may be used as exercise devices while not being worn as an exoskeleton. One approach to this functionality is illustrated in
The software controlling the powered knee joints 18 may be configured to do a variety of things in this exercise. A simple approach is for the knee joints to provide a constant gravity-simulating downward force on lower frame 32 to counteract the user's efforts. For example, if the desired exercise is to curl a 30 kg mass, the software can be configured so that the powered knee joints produce a constant 30 kg downward force on lower frame 32.
Of course, more complex loads may also be programmed. It is known in sports physiology, for example, that it is desirable to vary the load at different portions of the arc of the “curl.” Some stationary exercise machines use a cam feature to create this effect. The software controlling the powered knee joints may be configured to produce this kind of effect as well.
1. Provide a low starting load then increase the load once movement has begun;
2. Provide a zero-load “rest” position where the inventive exoskeleton fixes the position of the knee joints;
3. Provide a progressively increasing load to simulate “cam” type weight machines; and
4. Provide a pulsating load.
The inventive exoskeleton may provide many different types of load when it is being worn for “passive” muscular and skeleton maintenance (passive meaning that the user is performing other tasks and not concentrating on exercise). In this situation they device may be configured to do one or more of the following:
1. Provide a static load simulating gravity;
2. Provide a small variation in a static load to simulate muscle enervations needed for normal standing balance; and
3. Provide unequal loading of the two foot plates so that the user must apply an asymmetric reaction force.
Returning now to
Position adjustments may also be provided for the hip joints. As an example, the lower frame could include a lateral adjustment so that the lateral spacing between the robotic hip joints could be varied to accommodate differing anatomy.
The preceding description contains significant detail regarding the novel aspects of the present invention. It is should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Many other variations are possible. Thus, the scope of the invention should be fixed by the claims presented, rather than by the examples given.
This non-provisional patent application claims the benefit of a previously filed provisional application. The provisional application was assigned Ser. No. 62/087,389. It listed the same inventors.
| Number | Date | Country | |
|---|---|---|---|
| 62087389 | Dec 2014 | US |
