Mechanical engineering design of a hand rehabilitation device

U diplomskom radu obrađuje se tema razvoja uređaja za rehabilitaciju pokreta ljudske šake. Uređaj za rehabilitaciju i asistenciju pokreta šake još se naziva egzoskeletom. Rad se započinje analizom anatomije i kinematike ljudske šake. Definirane su kosti i zglobovi koji čine strukturu šake te mišići i tetive pomoću kojih se ostavaruju pokreti prstiju. Rad se nastavlja upoznavanjem sa trenutno postojećim egzoskeltima za rehabilitaciju stiskanja i otpuštanja šake. Egzoskelti se dijele na krute i mekane mehanizme. Kruti mehanizmi temelje se na sustavu polužica. Iako se za smatraju zaostalima, potrebno je razumijeti njihov princip rada zbog boljeg razumijevanja problematike razvoja egzoskeleta. U drugu kategoriju svrstavaju se mekani mehanizmi. U mekane mehanizme spadaju elastični i prilagodljivi sustavi poput uređaja temeljenih na principima pneumatskih mišića, kabela i „shape memory alloy“ aktuatora. Pomoću znanja stećenog analizom anatomije ljudske šake i trenutno postojećih egzoskeleta razvija se četiri koncepta uređaja za rehabilitaciju pokreta šake. Detaljnim opisivanjem koncepata te njihovih prednosti i mana određuje se koji koncept zadovoljava uvjete za daljnju razradu. Odabran je egzoskelet temeljen na principima „push-pull“ kabela. Ostatak rada posvećen je konkretizaciji konstrukcije i načina rada egzoskeleta. Konstrukcija novog uređaja temelji se na relativno jednostavnoj i brzoj metodi izrade pomoću 3D printanja. Princip rada egzoskeleta temelji se na jeftinim i lako dostupnim elementima. Razvijena je pogonska jedinica s pet linearnih aktuatora, odnosno s mogućnošću kontrole svakog prsta zasebno što omogućava najveću kompleksnost hvatova i rehabilitacije. Za smještaj linearnih aktuatora osmišljeno je kučište koje se postavlja na prsa korisnika. Završni dio rada posvećen je definiranju jednostavne kontrolne jedinice sa ciljem brze izrade protoipa.This thesis deals with development of a hand rehabilitataion device also known as hand exoskeleton. The paper begins with short introduction into anatomy and kinemtics of human hand. When dealing with topic of hand rehabilitation it's important to understand the structure of human hand and the principles on which muslces and tendons move and control the fingers. Hand exoskeleton is designed and built around the human hand so it has to conform to the hand anatomy and its range of motion. Developing a new hand exoskleton requieres understanding of mechanisms on wich curently existing ones are based on. Exoskeletons are devided into rigid and soft mechanisms based on the way the operate. Rigid exoskeletons are described as a system of rigid links connected in a way that results in natural finger motion. Even though they are considered too heavy and bulky for modern standards, it is important to know how they work in order to better understand the principles of hand exoskeleton development. Soft exoskeletons are elastic and compliant mechanisms such as systems driven by pneumatic muslces, cables resebemling tendon function and shape memory alloy actuators. Knowledge gained by analysing anatomy of the human hand and currently existing mechanisms is used to develop four concepts of exoskeletons. A detailed description of the concepts and their advantages and disadvantages helps to determine which concept meets the conditions for further elaboration. It is decided that an exoskeleton actuated by push-pull cables is the best option. The rest of the paper is dedicated to realization of said exoskelton. The design of new device is based on a simple and fast method of production using 3D printing technology. The working principle of the exoskeleton is based on cheap and easily accessible elements. Exoskeleton is actuated with five linear actuators which enables the greatest complexity of grips and rehabilitation. Actuators are placed in a housing which is then placed on users chest. The paper is brougth to a conclusion by developing a simple control unit with the aim of rapid prototyping