The Prüf- und Forschungsinstitut Pirmasens e.V. (PFI) would like to submit an IGF research application on the subject of "Exoskeleton-compatible safety shoes". IGF stands for "Industrial Collective Research" and is an established innovation funding programme of the Federal Ministry of Economics and Climate Protection (BMWK) specifically for small and medium-sized enterprises. The German Aerospace Centre (DLR) is the project sponsor of the IGF innovation funding programme.
Starting point
Safety shoes must fulfil a wide range of properties in order to be able to fulfil their protective and comfort function. Corresponding standards must be complied with. Exoskeletons are a technical innovation that makes both heavy and monotonous work easier in the field of professional work in industry, trade and agriculture. There are passive and active systems. Passive systems distribute the power supplied by the wearer in the relief phases by means of energy storage devices that release their energy again in the load phases, or provide relief through support functions. Active systems use electrical energy supply and electrical, pneumatic or hydraulic actuators to increase the possible overall performance of the work processes performed by the human body.
Exoskeleton systems that support leg movements - such as walking, squatting, lifting and running - must transfer the additional static and dynamic forces induced by the exoskeleton components to the ground, parallel to those that come directly from the human body. The systems that support the movements of the upper body also increase the ground reaction forces by adding weight.
The mechanically generated forces and movements of the exoskeletons for the lower extremities must be transferred to the ground or supported there. This can be done in four ways:
Parallel to the shoes via their own additional support surfaces on the floor - Coupling in next to the shoes via their own support components (exoskeletons with their own feet/rollers)
Via the human feet through the shoes worn - Coupling above the ankle joint (e.g. exoskeletons strapped to the upper body)
Parallel to the shoe or foot - past the shoe, shoe stands on the artificial foot of the exoskeleton (exoskeleton suit, exoskeleton accommodates human)
Parallel to the foot but through the sole of the shoe - coupling to the existing shoe (exoskeleton with coupling to shoes worn by humans below the ankle joint)
Task
Using the example of slip resistance, it can be shown that the use of exoskeletons influences the safety-relevant behaviour and wearing of shoes. The coupling of exoskeletons that influence gait leads to changes in slip resistance in all of the four types listed, either through additional contact elements, through increased or at least altered ground reaction forces and pressure distributions or through altered rolling behaviour.
Ensuring continued slip resistance when moving is a task that must also be guaranteed when wearing exoskeletons, as is generally regulated by standardised specifications when wearing safety shoes. This raises the question of how this can be ensured. Not only for slip resistance, but also for all other protective functions and tasks of the footwear.The smallest changes in safety behaviour and ergonomics between normal use of the footwear and use with exoskeletons appear to occur when the exoskeletons are attached via the shoe (4th type). This means that the tested shoe with its known safety-relevant properties transmits the additional forces and torques of the exoskeleton to the floor. This requires a sufficiently dimensioned coupling of the exoskeleton into the shoe that minimises interference with human physiological functions and the statics and dynamics of the foot. Ideally, there should be a standardised mechanical interface through which exoskeletons and shoes can be connected and through which forces, torques and movements can be transmitted without significant additional loads - e.g. on the ankle joints.
Goal
Accordingly, the aim is to develop a standardisable mechanical interface and a suitable shoe structure for safety shoes that have as little impact as possible on normal walking and can transfer the expected loads from exoskeletons to the ground via the upper and sole of the shoes without negatively affecting safety-relevant parameters or the comfort of shoe use.
Solution
The first step is to analyse the loads, forces, torques, kinematic changes and properties generated by the various possible and existing exoskeletons and how these affect gait and the statics and dynamics of walking. These results must then be transferred to the use of the footwear. Which movements can be transmitted through the shoe, which hinder normal walking, etc.? Requirements for the shoe are derived from this. What forces and torques need to be coupled and transmitted? How can these be transferred to the ground through the sole? Suitable couplings are then investigated and developed that can be integrated into shoes without significantly impairing the safety and comfort properties of the shoes, but ideally even improving them. Simulation techniques will be used for this design task. The most promising approaches will be tested on functional shoe models. Partners from the exoskeleton manufacturing industry will be used to implement and test corresponding couplings on the exoskeleton side. The biomechanical properties during walking and corresponding work processes will be recorded, examined and evaluated with and without coupled exoskeletons and corresponding optimisations will be made to the shoe and couplings. The solutions and approaches are to be presented or proposed to the relevant committees via the standardisation activities of the PFI.
Project participation
IGF-funded projects are accompanied by a project support committee (PA), whose members are made up of representatives from industry who are interested in the topic. The PA monitors the project throughout its entire duration and can actively influence it with its input.
We would like to invite you to participate in the development together with us.
As a member of the project committee, you will fulfil the following tasks:
- Participation in PA meetings:
You or a representative of your company will attend the PA meetings about once or twice a year. At these meetings, the research centres report on the current status of the project work and explain the next steps. In this way, you are informed about the project results at an early stage and at first hand. These meetings are also intended to provide a platform for open discussions. Your input, your experiences and your wishes are particularly welcome here.
Apart from participation in the PA meetings and the associated travelling expenses, no financial commitment is required on your part. However, it is very important for us to receive feedback from industry on the extent to which there is interest in the results of the research project. This interest on the part of industry is mandatory for the realisation of the project and we are obliged to prove this to DLR in the form of project-related expenditure by industry (vAW). In concrete terms, this means that our research work would benefit greatly if you were to support the project beyond a purely advisory role.
These vAW can take the form of, for example
- Discussing the requirements of exoskeleton and shoe manufacturers as part of an informative conference on the topic
- Providing various shoes for tests on the state of the art or the development of coupling options for safety shoes
- Provision of exoskeletons for tests
- Declaration of willingness to cooperate with the PFI and function as contact person
- Participation in the meetings of the project committee
We would be pleased to have aroused your interest with our idea. We will be happy to answer any questions you may have.
Florian Dieudonne
E-mail: florian.dieudonnepfi-germanyde
Phone: 06331 / 2490 922
If you are interested in participating in the project monitoring committee, please complete the non-binding declaration of participation, stamp and sign it, scan it and send it back to us by e-mail.
Your participation will increase the chances of the project being approved. By expressing your interest, you will automatically be included in the project advisory committee of the research project and benefit from the latest research results.