Human powered hydraulic exoskeleton

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Discussion Overview

The discussion centers around the design of a hydraulic exoskeleton that utilizes the kinetic motion of the human body as its input force, aiming to amplify this force for various applications. Participants explore concepts related to the mechanics, design considerations, and potential challenges of such a system, without reaching any conclusions or consensus.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant proposes designing a hydraulic exoskeleton that converts the body's kinetic motion into hydraulic force, suggesting an input force of 20 kg could yield an output of 80 kg.
  • Several participants question the feasibility of achieving such a force amplification without an external power source, expressing skepticism about the practicality of the design.
  • Another participant emphasizes the importance of starting with a clear concept and understanding the various disciplines involved in the design process, including dimensions, forces, and materials.
  • Concerns are raised about the safety of users when the exoskeleton significantly amplifies force, highlighting the need for regulation to protect against excessive forces.
  • Some participants note the importance of providing more detailed information about the design challenges faced to facilitate better assistance from others.
  • There is a discussion about the proper units of force, with some participants correcting the use of "kilograms" instead of the appropriate unit of "kilogram force" (kgf).

Areas of Agreement / Disagreement

Participants generally express skepticism regarding the feasibility of the proposed design without an external power source, and there is no consensus on the best approach to achieve the desired force amplification. The discussion remains unresolved with multiple competing views on the design and safety considerations.

Contextual Notes

Participants mention the need for a comprehensive understanding of mechanical advantage and the potential trade-offs involved in force amplification. There are unresolved questions regarding the specific mechanics of the proposed system and the implications of force output on user safety.

The Orange
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I want some suggestion about designing a hydraulic exoskeleton whose input would be the kinetic motion of the body...the force exerted by body would be used to give an input to the hydraulic system which would inturn give a larger force as output in real time.for example an arm with exoskeleton is flexed at elbow joint by a force of 20 kg these kgs would be the input force for the system which in turn would move the exoskeletal joint with a large force let it be 80kgs
 
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There is very little on available on this topic...yes i have searched for it
 
The Orange said:
I want some suggestion about designing a hydraulic exoskeleton
This is a broad topic. I'm not an expert on hydraulics but the answers could range from "do lots of reading" to the specifics of designing various motors. It helps if you explain what you've done and where you're stuck. It makes it easier for others to help you.
Also, take a look at the list of similar discussions at the bottom of the page. You might get some ideas from there as well.
 
Yes very broad topic.

For a design, one has to begin with a concept, which can range from that featured in the wiki article from Borg, where the system is attached next to the human body, to something such as portrayed in the movies, such as the assisted freight forklift system used by Sigourney Weaver in Alien, where the user can just enter into the machine and easily activate; or as elaborate as that from the movie Ativar. You will need to be familiar with several disciplines, as shown in the Wiki.

Start.
From the concept, one can determine possible dimensions of the machine and its components, and possible range of movements.
From there, forces, torques, stresses and strains at the various joints and members.
Next, a selection of the components, which would include the actuators, sensors, power supply, materials for the members, etc.
Keep a running bill of materials into which one adds the component, dimensions, material and amount, cost of fabrication, time for assembly,etc
Additional list items ...
Go to start if something needs adjustment, expect to do that several times.

Once done, select a paint color, logo. ( you could do this at just about any time but it will change )

End:

Present it to the world.
And charge a lot.

Don't expect to do it all in one weekend.
 
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256bits said:
Yes very broad topic.

For a design, one has to begin with a concept, which can range from that featured in the wiki article from Borg, where the system is attached next to the human body, to something such as portrayed in the movies, such as the assisted freight forklift system used by Sigourney Weaver in Alien, where the user can just enter into the machine and easily activate; or as elaborate as that from the movie Ativar. You will need to be familiar with several disciplines, as shown in the Wiki.

Start.
From the concept, one can determine possible dimensions of the machine and its components, and possible range of movements.
From there, forces, torques, stresses and strains at the various joints and members.
Next, a selection of the components, which would include the actuators, sensors, power supply, materials for the members, etc.
Keep a running bill of materials into which one adds the component, dimensions, material and amount, cost of fabrication, time for assembly,etc
Additional list items ...
Go to start if something needs adjustment, expect to do that several times.

Once done, select a paint color, logo. ( you could do this at just about any time but it will change )

End:

Present it to the world.
And charge a lot.

Don't expect to do it all in one weekend.
 
The suggestion i was asking is about the design of the system converting kinetic motion of body into the motion of the hyraulic cylinder...the exoskeleton don't need external power source its powered from the motion of the human body...mechanically...what type of system would u suggest to be the best
 
The Orange said:
The suggestion i was asking is about the design of the system converting kinetic motion of body into the motion of the hyraulic cylinder...the exoskeleton don't need external power source its powered from the motion of the human body...mechanically...what type of system would u suggest to be the best
No outside power source? And you want to turn 20 units of force into 80? Good luck with that.
The Orange said:
for example an arm with exoskeleton is flexed at elbow joint by a force of 20 kg these kgs would be the input force for the system which in turn would move the exoskeletal joint with a large force let it be 80kgs
You might want to read up on units of force while you're at it. Kilograms isn't in the list.
 
  • #10
Borg said:
No outside power source? And you want to turn 20 units of force into 80? Good luck with that.

You might want to read up on units of force while you're at it. Kilograms isn't in the list.
 
  • #11
Borg said:
No outside power source? And you want to turn 20 units of force into 80? Good luck with that.

You might want to read up on units of force
Borg said:
No outside power source? And you want to turn 20 units of force into 80? Good luck with that.

You might want to read up on units of force while you're at it. Kilograms isn't in the list.

while you're at it. Kilograms isn't in the list.
 
  • #12
Tell me how much force u exert on a human operated hydraulic jack to lift a truck...and kilogram force is used as unit of force...
 
  • #13
The Orange said:
kilogram force is used as unit of force
The abbreviation for that is kgf not the kg that you used.

You still haven't said what you've tried or where you're stuck. Honestly, PF gets plently of questions like this where the poster asks questions like this. Unless you're willing to provide more information, it's unlikely that you'll get much help. It's more likely that an administrator will stroll by and lock the thread.
 
  • #14
The Orange said:
The suggestion i was asking is about the design of the system converting kinetic motion of body into the motion of the hyraulic cylinder...the exoskeleton don't need external power source its powered from the motion of the human body...mechanically...what type of system would u suggest to be the best
You are the one with the idea, so you must have some beginning framework in mind and what you hope to accomplish.

The work to lift 80 kg ( as you previously mentioned ) has to come from somewhere, and if you are using the human body as the power source, then you will expend just as much energy with or without an "exoskeleton".

Using a mechanical advantage device, such as a jack, becomes a tradeoff between how much can lifted and the amount ( distance ) of lift. The distance in stroke you provide to the jack lever, if you had not noticed, is much greater than the distance the weight travels. Nevertheless, the amount of work you provided is the same as the gain in potential energy of the weight.

I have to agree with Borg's previous post.
It is fun to have a guessing game when playing 20 Questions, but I do think you want to be taken more seriously than that.
 
  • #15
the problem I'm seeing with this concept is not how to increase the force put into the exoskeleton but how you protect the user from the increased force output.

if the exoskeleton adds 4X's the force how will the user be protected from the results. like bending the hip and it wants to move 4X's as hard in the direction of travel which needs 4X's as much force to stop moving if its not regulated the user could be subjected to some pretty nasty forces. where as if the unit is not a direct drive. sort of like the one in aliens a big biped forklift then you would be using motors or engines to create the strength and sensors to control the movement this removes the user from the forces being created. direct drive can assist movement but is limited in how much it can increase the force the user is exposed to.
 
  • #16
but let's go on another tangent: say what you want to do is soak up wasted energy and use it. sort of like the energy each step creates when you plant your foot and you sponge up that energy and use it to run something else like a hip joint piston. you could reduce the amount of effort needed for forward motion by a fairly equal amount as the amount of energy soaked up by each foot planting as you walk. the issue is as much as you gain with the device.it will be reduced by the amount of extra weight you need to carry to create the assisted motion.
 

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