Tesi etd-07092024-163647
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Tipo di tesi
Dottorato
Autore
CAPITANI, STEFANO LASZLO
URN
etd-07092024-163647
Titolo
self-aligning mechanisms in wearable robotics: design and development of solutions to enhance kinematic compatibility and address misalignment challenges
Settore scientifico disciplinare
ING-IND/34
Corso di studi
Istituto di Biorobotica - PHD IN BIOROBOTICA
Commissione
Presidente Prof. VITIELLO, NICOLA
Membro Dott.ssa CORDELLA, FRANCESCA
Membro Dott.ssa CORDELLA, FRANCESCA
Parole chiave
- Self-Aligning Mechanisms (SAMs)
- Kinematic Compatibility
- Upper Limb Exoskeletons
- Rehabilitation Robotics
- Wearable Robotics
Data inizio appello
26/02/2025;
Disponibilità
parziale
Riassunto analitico
Wearable robotics is rapidly advancing, with significant potential in rehabilitation engineering, assistive robotics, and power augmentation. A critical challenge in this field is the physical human-robot interface, which affects device efficacy, kinematic compatibility, and adaptability to diverse anthropometries. Misalignment between the robot and user's joints can lead to ineffective torque control and undesired forces on articulations and soft tissues, compromising safety and comfort.
While macroscopic regulation of robot link lengths has been proposed as a solution, it is often affected by imprecision and relies heavily on experimenter skill. This approach cannot fully compensate for variable misalignments and may affect the robot's mechanical integrity and dynamical parameters.
Self-aligning mechanisms (SAMs), previously introduced in literature as a promising approach to address these challenges, exploit passive degrees of freedom to achieve kinematic compatibility. This work applies the SAM concept to create new robots with enhanced characteristics for rehabilitative and assistive applications. The primary causes of misalignment in wearable robotics are twofold: firstly, the difficulty in accurately identifying the center of rotation of human; and secondly, the fact that this center of rotation does not remain fixed during movement. SAMs address these issues by accommodating the complex and dynamic nature of human joint movement, thereby improving alignment throughout the range of motion. These features are particularly crucial in rehabilitative and assistive robots, where precise alignment and efficient torque transfer are essential for therapeutic efficacy and user comfort.
In this scientific activity, SAMs were applied to two complex anatomical regions: the hand and the shoulder. For finger flexion/extension rehabilitation and assistance, two devices were developed: I-PhlEx and H-PhlEx. The implementation of SAMs in these hand devices was crucial for guaranteeing correct torque transfer while simultaneously allowing measurement of key parameters essential for rehabilitation scenarios. I-PhlEx, a single-finger platform for clinical environments, implements a novel kinematic chain and a mathematical model for real-time computation of joint angles and torque transfer. H-PhlEx, an enhanced portable version, includes a lockable thumb SAM for grasping objects during rehabilitation.
For arm elevation and overhead tasks, GraCE, a portable multi-function exoskeleton, was developed. In this shoulder scenario, the implementation of SAMs was fundamental as it enabled multiple modules to work in series on different anatomical joints. GraCE combines a Series Elastic Actuator at the elbow with spring-loaded elements on the back and shoulder to create an active SAM, demonstrating the versatility of this approach in complex multi-joint systems.
All devices underwent testing on healthy subjects, with I-PhlEx also evaluated on patients. Results demonstrated the effectiveness of the devices and, crucially, their self-aligning properties. This work contributes to the field of wearable robotics by showcasing the potential of SAMs in enhancing kinematic compatibility, improving torque transfer, and enabling multi-joint functionality in complex anatomical regions. Future research directions include in-depth studies of human-robot interaction to quantify transferred torques and forces, as well as further exploration of SAM efficacy in various wearable robotic applications.
While macroscopic regulation of robot link lengths has been proposed as a solution, it is often affected by imprecision and relies heavily on experimenter skill. This approach cannot fully compensate for variable misalignments and may affect the robot's mechanical integrity and dynamical parameters.
Self-aligning mechanisms (SAMs), previously introduced in literature as a promising approach to address these challenges, exploit passive degrees of freedom to achieve kinematic compatibility. This work applies the SAM concept to create new robots with enhanced characteristics for rehabilitative and assistive applications. The primary causes of misalignment in wearable robotics are twofold: firstly, the difficulty in accurately identifying the center of rotation of human; and secondly, the fact that this center of rotation does not remain fixed during movement. SAMs address these issues by accommodating the complex and dynamic nature of human joint movement, thereby improving alignment throughout the range of motion. These features are particularly crucial in rehabilitative and assistive robots, where precise alignment and efficient torque transfer are essential for therapeutic efficacy and user comfort.
In this scientific activity, SAMs were applied to two complex anatomical regions: the hand and the shoulder. For finger flexion/extension rehabilitation and assistance, two devices were developed: I-PhlEx and H-PhlEx. The implementation of SAMs in these hand devices was crucial for guaranteeing correct torque transfer while simultaneously allowing measurement of key parameters essential for rehabilitation scenarios. I-PhlEx, a single-finger platform for clinical environments, implements a novel kinematic chain and a mathematical model for real-time computation of joint angles and torque transfer. H-PhlEx, an enhanced portable version, includes a lockable thumb SAM for grasping objects during rehabilitation.
For arm elevation and overhead tasks, GraCE, a portable multi-function exoskeleton, was developed. In this shoulder scenario, the implementation of SAMs was fundamental as it enabled multiple modules to work in series on different anatomical joints. GraCE combines a Series Elastic Actuator at the elbow with spring-loaded elements on the back and shoulder to create an active SAM, demonstrating the versatility of this approach in complex multi-joint systems.
All devices underwent testing on healthy subjects, with I-PhlEx also evaluated on patients. Results demonstrated the effectiveness of the devices and, crucially, their self-aligning properties. This work contributes to the field of wearable robotics by showcasing the potential of SAMs in enhancing kinematic compatibility, improving torque transfer, and enabling multi-joint functionality in complex anatomical regions. Future research directions include in-depth studies of human-robot interaction to quantify transferred torques and forces, as well as further exploration of SAM efficacy in various wearable robotic applications.
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