Miha Dezman

Karlsruhe Institute of Technology | KIT · Institute of Anthropomatics

Online adaptation of exoskeleton control based on muscle activity sensing is a promising way to personalize exoskeletons based on the user's biosignals. While several electromyography (EMG) based methods have been shown to improve joint torque estimation, EMG sensors require direct skin contact and complex post-processing. In contrast, force myogra...

Exoskeleton devices impose kinematic constraints on a user's motion and affect their stability due to added mass but also due to the simplified mechanical design. This paper investigates how these constraints resulting from simplified mechanical designs impact the gait kinematics and stability of users by wearing an ankle exoskeleton with changeabl...

Electromechanical variable stiffness actuators 1 (VSA) can store and reuse different amounts of energy in the 2 elastic element by varying the stiffness, but they are typically 3 heavy for use in exoskeletons because they require more than 4 one motor. At the same time, the use of pneumatic actuators in 5 exoskeletons is suitable due to their high...

Exoskeleton devices may impose kinematic constraints on a user’s motion and affect their stability due to added mass and inertia, but also due to the simplified mechanical design. This study explores the impact of kinematic constraints imposed by exoskeletons on user gait, stability, and perceived discomfort. Specifically, it examines how the varyi...

This paper presents a portable stand-alone pneumatic knee exoskeleton that operates in both passive and active modes. The system can store and recover energy by means of compressed air in passive mode, leading to energy savings. In active mode, a small air pump inflates the pneumatic artificial muscle (PAM), which stores the compressed air, that ca...

Exoskeletons are becoming the reference technology for assistance and augmentation of human motor functions in a wide range of application domains. Unfortunately, the exponential growth of this sector has not been accompanied by a rigorous risk assessment (RA) process, which is necessary to identify the major aspects concerning the safety and impac...

Evaluating human-exoskeleton interaction typically requires experiments with human subjects, which raises safety issues and entails time-consuming testing procedures. This paper presents a mechatronic replica of a human leg, which was designed to quantify physical interaction dynamics between exoskeletons and human limbs without the need for human...

Exoskeletons are a promising tool to support individuals with a decreased level of motor performance. Due to their built-in sensors, exoskeletons offer the possibility of continuously recording and assessing user data, for example, related to motor performance. The aim of this article is to provide an overview of studies that rely on using exoskele...

p>Electromechanical variable stiffness actuators (VSA) can store and reuse different amounts of energy in the elastic element by varying the stiffness, but they are typically heavy for use in exoskeletons because they require more than one motor. At the same time, the use of pneumatic actuators in exoskeletons is suitable due to their high power-to...

Electromechanical variable stiffness actuators (VSA) can store and reuse different amounts of energy in the elastic element by varying the stiffness, but they are typically heavy for use in exoskeletons because they require more than one motor. At the same time, the use of pneumatic actuators in exoskeletons is suitable due to their high power-to-w...

Exoskeletons and other wearable devices benefit from sensor systems that are based on biofeedback for detecting muscle activity. However, such sensor systems in wearable applications are often impractical due to the need for direct skin contact or due to non-linear signal output, both requiring extensive calibration and post-processing. This paper...

This paper presents a lightweight and low-inertia cable-driven upper-limb exoskeleton powerful enough to meet the requirements for activities of daily living. It presents the mechanical design, kinematic structure,the underlying actuation system, sensors, other electronic components as well as the controller of the exoskeleton. The extensive effect...

State-of-the-art compliant actuators with variable stiffness, meet the requirements for exoskeletons only to a limited extent, usually due to their higher mechanical complexity and large mass. In this paper, we present a quasi-passive lightweight pneumatic mechanism that emulates stiffness modulation in the pneumatic cylinder using fast-switching v...

Quasi-passive exoskeletons have emerged as a solution that avoids the high energy requirements that negatively affect the efficiency of exoskeletons. These exoskeletons do not deliver positive mechanical work to the joint, but accumulate and deliver energy in a viscoelastic element that is actively placed or removed parallel to the user's muscles....

Our pseudo-linear variable-lever variable stiffness actuator (PLVL-VSA) allows almost linear torque deflection characteristics in a compact form. However, in its original form, this advantage of the PLVL-VSA comes at a cost of increased stiffness variation torque, which limits the passive deflection range. In this work we propose a modification of...

This paper presents a novel variable stiffness mechanism based on the combination of a rotatable cam and a variable-ratio lever principle. The proposed configuration results in i) a pseudo-linear torque/deflection characteristics, where ii) the stiffness is varied rotationally and perpendicularly to the external load. The first is convenient for ea...

Among the growing number of different exoskeletons, passive and quasi-passive solutions hold the upper-hand compared to powered solutions in price, accessibility, complexity, weight and user acceptance. This paper evaluates a modification of an originally passive ankle exoskeleton with an active clutch, making it quasi-passive. We developed an elec...

Exoskeletons can be utilized for rehabilitation purposes as well as for assistance and augmentation of motion of patients with disabilities, workers, elderly and even healthy people. Compared to powered solutions, unpowered passive exoskeletons have been shown to have significantly higher chances of end user acceptance, because of simpler design, n...