In this work, we propose a method of processing patient input on discomfort level during robot shoulder physiotherapy into discomfort maps. These maps represent the patient's discomfort distribution throughout the range of motion of the shoulder, interpretable by both physiotherapists and robots. This method consists of three parts: the patient can input discomfort with a linear push-button; a collaborative robot arm is used to track the motion of the patient's shoulder; and audiovisual feedback of inputted discomfort is given to the patient and the therapist.
The method was validated in human factors experiments simulating shoulder physiotherapy sessions, where the subject is tasked with recreating a reference discomfort map through an auditory reference signal that emulates this discomfort. Here the robot also acts as the physiotherapist, moving the subject's shoulder. The signal is a beeping sound, whose rate scales with the discomfort intensity at the measured pose in the reference discomfort map.
We performed experiments with a total of 10 participants, demonstrating the viability of our method during patient-robot interaction. The results we collected also highlighted the presence of a time delay between the discomfort signal and the user input, and its effect on discomfort maps.

This study investigated the effects of lifting and carrying activities on ambulatory blood pressure (BP) responses in healthy adults. Participants performed simulated infant carrying tasks with different weight loads (0kg, 5kg and 10kg) using two lifting techniques (stoop and flat). Continuous BP was measured using the Finapres NOVA ambulatory BP monitor. The indicative results showed increases in peak systolic BP during lifting (5 kg: stoop +44.0 mmHg \& flat +41.1 mmHg) and average SBP during carrying phases (5 kg: stoop +12.96 mmHg \& flat +12.04 mmHg) compared to unloaded situations, with greater BP elevations observed for heavier loads (lifting 10 kg: stoop +56.9 mmHg \& flat +43.2 mmHg; carrying 10 kg: stoop +19.87 mmHg \& flat +14.11 mmHg). The lifting technique also impacted BP responses, as stoop lifting produced higher systolic BP peaks than flat lifting (+5.9 mmHg, +8.8 mmHg \& +19.6 mmHg for 0 kg, 5 kg \& 10 kg respectively). Detailed analyses were conducted by defining quantitative parameters such as baseline BP, peak BP during lifting, start BP after lifting, and end BP before lowering. The findings from this study have implications for developing guidelines on safe lifting and carrying practices for individuals with conditions like Marfan syndrome, which are prone to aortic complications from elevated BP.

Introduction: Movement disorders, such as Cerebral Palsy, prevent children from fully developing their motor coordination abilities reducing their quality of life. Trunk control is a core coordination competency but there is limited variety in sitting based therapies. This paper investigates a theorised trunk support device for children which uses a system of elastic ropes and pulleys to support and prevent them from falling whilst they perform trunk control training exercises in a seated position. The aim of this study is to understand the mechanical properties required to ensure this device behaves safely and predictably. The device is considered safe if it prevents the child from falling and predictable if it always pulls the child towards an upright seating position. Additionally, it was investigated if the mechanical properties could be satisfied by off-the-shelf components and two possible pulley systems were compared.

Methods: To theoretically test if this device concept could meet the three criteria, a MATLAB simulation was written. A genetic optimization was then used to find the least stringent mechanical properties that still satisfy the three criteria. Off-the-shelf components that satisfy the mechanical properties were then found.

Results: Both pulley systems satisfied the safety and predictability criteria. Moreover, the necessary mechanical properties could be satisfied by off-the-shelf components, though some design modifications may be required. Ultimately, the configuration involving shorter ropes was determined to be the better option as it had less stringent mechanical requirements and potential design modifications would likely be easier to implement.

Conclusion: This study concluded that the optimised device, theoretically, shows good performance and seems practical to build. Future work is required to design a harness that would allow a child to comfortably train with the device.

Fear of pain is a psychological consequence that can hinder an athlete’s ability to resume their previous level of performance or even return to their sport. A desire exists to examine the influence of fear of pain on both mechanical and neural factors involved in postural control, particularly focusing on the lower extremities. Previous literature shows associations between jump tests and fear of pain, but existing methods cannot differentiate between neural and mechanical factors, necessitating a different approach. Given the absence of a method to measure lower extremity reflexes and intrinsic properties similar to those observed in the shoulder, the original Proprio setup was adapted for leg perturbation to investigate its impact on lower extremity postural control. The adapted setup consists of a platform for participants to stand on, with coupling provided by a stiff ankle brace. A group of seven participants performed a slack trial and multiple stiff trials in both angled and neutral positions. Metrics such as admittance, stiffness, and coherence were calculated for each trial. The suitability of the setup was evaluated based on the selectivity of results across different trials and positions. Additionally, coherence was assessed, indicating the linearity which is necessary for future parameter identification. Notable differences in admittance and stiffness were observed between different legs and trials. This demonstrates the ability of the new setup around the Proprio to differentiate between various conditions. Comparisons with previous studies on shoulder dynamics showed similar findings, suggesting accurate measurement of leg dynamics. High coherence values indicated linearity, supporting the potential for future estimation of intrinsic parameters and reflex gains in leg dynamics. Considering these factors, the adapted Proprio setup appears suitable for analyzing lower extremity postural control. The next steps include expanding the participant group for significance and parameter identification, which will enable the investigation of the impact of fear of pain on intrinsic and reflexive properties using this setup.

This thesis explores the application of origami-inspired inflatable structured sheets to enhance muscle function for individuals with muscle impairments, specifically focusing on the biceps brachii muscle. These sheets induce muscle contraction through pneumatic pressure, aimed at facilitating forearm flexion by strategically incorporating patterns that create air pockets. These sheets hold significant potential for assisting individuals with conditions such as muscular dystrophy, cerebral palsy, or spinal cord injuries. Compared to traditional solutions, they offer less bulkiness and greater adaptability, promoting natural movement and improving limb mobility. Furthermore, these sheets can be customized to fit various muscle contours and integrated with mechatronics for real-time adjustments, enhancing stability and resilience in muscle support applications. The study begins with the development of a comprehensive test setup that simulates muscle extension and flexion, integrating mechanical and electrical components. This setup includes a silicone muscle model of the biceps brachii muscle, essential for evaluating sheet performance. Subsequent chapters delve into the evaluation of materials and patterns for the sheets. Materials such as PVC-film, TPU-film, PET-film, and Nylon are assessed for biocompatibility, flexibility, temperature sensitivity, and adhesion characteristics. Here, TPU-film emerges as the most promising material due to its durability and adhesive properties under pressure. For the evaluation of the patterns, a preliminary study is conducted to determine optimal patterns that effectively respond to pneumatic pressure for inducing muscle contraction. This study reveals that combinations of parallel lines and zigzag structures show the most promising results among the tested patterns. Building on these findings, various structured sheets are tested around the muscle model to assess their ability to activate and contract muscles. An optimal structure is selected that conforms closely to the contours of the muscle model, ensuring optimal airflow and maximizing the potential for effective muscle contraction. However, challenges such as leakage affecting pressure retention and muscle activation are identified, underscoring the need for further optimization to achieve practical muscle activation and flexion. In conclusion, while this research provides valuable insights into the feasibility of origami-inspired structured sheets for muscle augmentation, ongoing refinement is crucial to address practical challenges and optimize performance.

This paper aims to explore innovative fabrication methods for assistive gloves using origami design principles. The study addresses the limitations of current assistive gloves, such as bulkiness and lack of customisation, by developing a novel fabrication method that improves ergonomic design and manufacturing flexibility. The proposed method integrates 3D printing and welding techniques to create lightweight, customisable gloves that enhance rehabilitation for individuals with hand impairments, particularly stroke survivors. The paper details the design process, and testing methods, concluding with successfully creating a new fabrication approach for origami-based assistive gloves.

Human intention detection with hand motion prediction is critical to drive the upper-extremity assistive robots. However, the traditional methods relying on physiological signal measurement are restrictive and often lack environmental context. We propose a novel approach that integrates gaze information, historical hand motion sequences, and environmental object data to predict future sequences of intended hand poses, adapting dynamically to the assistive needs of the patient without prior knowledge of the intended object for grasping. Specifically, we propose to use a vector-quantized variational autoencoder for robust hand pose encoding with an autoregressive generative transformer for effective hand motion sequence prediction. We demonstrate the usability of these novel techniques in a pilot study with healthy subjects. To train and evaluate the proposed method, we collect a dataset consisting of various types of grasp actions on different objects from multiple subjects. Through extensive experiments, we demonstrate that the proposed method can successfully predict sequential hand movement. Especially, the gaze information shows significant enhancements in prediction capabilities, particularly with fewer input frames, highlighting the potential of the proposed method for real-world applications.

This research investigates methodologies to reduce and implement negative inertia in robots for upper extremity diagnostics and rehabilitation. The robot’s responsiveness is enhanced by integrating accelerometers and Kalman filters into the control scheme, ensuring smoother physical human-robot interactions. A force gain that mimics negative inertia significantly improves system dynamics within the admittance control framework. Introducing dead zones for force and acceleration stabilizes responses at lower rendered inertia, crucial for handling spastic conditions. However, this research identifies a lack of standardized evaluation methods for negative inertia and highlights hardware constraints, such as bandwidth limitations, that restrict performance. Future research should focus on establishing evaluation standards and optimizing hardware to refine control precision. This work demonstrates the potential of advanced control strategies to optimize robotic rehabilitation, paving the way for more effective diagnostic and therapeutic interventions.

Work-related musculoskeletal disorders (WRMSDs) are prevalent among sonographers, particularly affecting the shoulder region due to repetitive and static movements. This study introduced an ergonomic posture and a mobile arm support (MAS) to reduce the load of muscles contributing to the stabilization of the shoulder. The experimental setup replicated a conventional cardiac ultrasound examination, using a phantom model and simulations to mimic cardiac ultrasound procedures. Professional cardiac sonographers were instructed to acquire three cardiac views (parasternal long-axis view (PLAX), apical four-chamber view (A4C), and subcostal window(SCW)) while surface EMG and joint angles of the shoulder, elbow, and back were measured. Additionally, subjects were tasked with completing a questionnaire to gather subjective outcomes of usability and satisfaction with the support and ergonomic posture. Muscular activity of the middle deltoid muscular activity (PLAX; F(3,12)10.15,p=.001,η2 p=.717, A4C; F(3,12)=5.75,p=.011,η2 p=.590) and superior trapezius (PLAX; F(3,12)=7.05,p=.005,η2 p=.638) decreased significantly during examinations with postural changes but increased significantly while only support was provided. The support was considered slightly useful (SUS=65.0±6.9, α=.585), but the ergonomic change was considered poor (SUS=43.0.0±14.4, α=.813). The increase in muscular activity was likely caused by incorrect placement of the MAS on the upper extremity and incorrect levels of support. Besides, sonographers reported a MAS would be useful when there is an additional functionality that applies contact force through the MAS. The addition of support to postural changes did not significantly reduce muscular load compared to examinations with only postural changes. Therefore, ergonomic postural change is a sufficient solution for mitigating WRMSDs development due to the only significant decrease in muscular activity.

In Upper Motor Neuron Lesion (UMNL) following stroke, patients can experience increased joint impedance, resisting joint rotation and hindering functional movement. This heightened impedance in UMNL is driven by both exaggerated reflexes and increased intrinsic muscle activation through co-contraction, hypertonus, or synergies. The simultaneous presence of these mechanisms complicates clinical distinction, especially given their theorised interplay, where increased intrinsic activation would further heighten reflex responses. Separate quantification of this intrinsic and reflexive impedance and their interaction, can aid in further investigation of the pathophysiology of post-stroke joint impairment and its treatment.

This work presents the investigation of an Open Loop System Identification (OL-SID) protocol, to perform this separate quantification of intrinsic and reflexive impedance for the elbow joint. Perturbation experiments were performed with 16 healthy subjects, using multisine positional perturbations and measuring the elbow torque response. An impedance model consisting of both intrinsic and reflexive parameters was fit to the estimated frequency response function (FRF), relating perturbation angle to joint torque. It was assessed how background muscle activation, as well as the frequency and velocity of the perturbation signal, influenced the modelled intrinsic stiffness, intrinsic damping, and reflex velocity-gain.

For this, three different biceps muscle activation levels were requested from the participants in different trials; 0%, 10%, and 30% of Maximum Voluntary Contraction (MVC), as confirmed by online EMG measurements. Participants were requested to not actively resist perturbations, but only to comply with the requested biceps activation level. Furthermore, three rotational multisine perturbations with a max. amplitude of 2 degrees were applied; Wide Bandwidth - High Velocity, Narrow Bandwidth - Low Velocity, and Wide Bandwidth - Low Velocity. Cross-combination of biceps activation levels and perturbation signal resulted in 9 impedance quantifications per participant.

Increased biceps activation resulted in a significant increase of intrinsic stiffness, intrinsic damping, and the reflex-gain. This confirmed the expected relationship between muscle activation and intrinsic impedance, as well as the theorised relation between intrinsic activation and the reflex response. Unexpectedly, differences in used perturbation bandwidth or velocity showed no clear influence on identified reflex gain. This contradicts findings of reflex suppression during high-bandwidth force perturbations in tasks that require resisting these perturbations, as well as during high-velocity binary or unidirectional joint stretches. This discrepancy shows that joint system identification results are highly dependent on perturbation type and subject task, emphasising the need to align the experimental design with the clinical question at hand.

Despite some shortcomings regarding low coherence of the estimated FRFs, and necessary further research on perturbation signal properties and their effect on the reflex response, the results of this study are promising. The observed trends in fitted parameters with increased activation levels in line with physiological expectations, indicate the ability of this technique to validly identify reflexive and intrinsic joint impedance. This distinction is highly valuable for advancing investigation of the pathophysiology and clinical presentation of UMNL post-stroke, in the pursuit of adequate treatment for different patients.

The provision of somatosensory information may play a fundamental role in the recovery of stroke patients. Particularly, tactile information is known to influence motor control by contributing to the perception of the weight, friction, and slip condition of objects. Despite this, the inclusion of tactile information through haptic rendering in robotic neurorehabilitation systems remains largely unexplored. In this study, we present a tactile interface to extend the kinesthetic rendering capabilities of an existing hand rehabilitation robot. The developed solution relies on skin stretch stimulation of the fingerpads, which allows the rendering of interaction forces with tangible virtual objects, e.g., friction, weight, and inertia. In contrast with previous skin stretch devices, our system uses closed-loop force control for accurate force rendering, relying on a custom magnetic field-based three-axis force sensor. A three-axis positioning stage in combination with a reference force sensor was used for calibrating and characterizing the sensor, as well as evaluating the interface response. The sensor achieves shear force accuracies of 0.2 N, influenced by hysteresis and viscoelastic creep effects. The tactile interface achieves a steady-state error of 0.2–0.4N and rise times of 20–70 ms during step response tests. Frequency response tests show that the interface can successfully track signals up to 5–7 Hz. The novel use of force-controlled skin stretch stimulation aims to open a new avenue for the accurate rendering of interaction forces through the tactile sense. Moreover, through purposeful design for usage in the rehabilitation domain, we hope that this study will serve as a stepping stone toward the inclusion of tactile information in robot-assisted therapies.

Automation within an industrial sector has now for years been an obvious factor. Everywhere mechanical instruments and sensors are implemented for fast and precise processes. The agricultural sector is some steps behind in relation to other sectors. Reason being that there are many irregularities which in other sectors have been made into uniform variables. One of the problems that needs to be tackled within the agricultural sector is having the leaves of crops removed.
Rijk Zwaan has created a new variety of broccoli and to make this commercially viable, a harvest machine is required. One of the aspects of this harvesting process is removing the leaves. This has to be achieved in one continuous session, with at least a ground speed of 1 km/h, while the broccoli's are still in the field. With a focus on the best performance for the least destructive working principle. After listing all the requirements, ideas are structured in a morphological overview. A weighted criteria table will be used to select three ideas, which will be made into prototypes.
Results from the initial testing period will reveal the best concept, which will be optimised. This was the Metal Wire design, which exist of multiple stainless steel wires attached perpendicular to a rotating shaft. An important aspect that boosted the performance was the unravelled ends of these wires. These rotating shaft had the wires removing the leaves, while beating the leaves down from both sides.
After optimization, the current prototype could ensure a 60% of the top section and 80% of the middle section with 20% of the broccoli’s destroyed. Which was not enough to satisfy the goal, however the promising results could be improved with an upgraded machine. A clear trade-off was found between the performance and destruction. Significant improvements in results could be achieved by incorporating additional features such as a funnel and designing a more robust structure with fewer obstructions, controllable ground/rotational speed, and better alignment with the beds. Therefore at the current state the leaf removal machine operates substandard, but has potential to be developed into the desired product.

Humans perceive a pulling or pushing sensation when subjected to an asymmetric vibration. This so-called pseudo force has great potential to guide human movement. Previous research has exclusively focused on the effect of pseudo forces in open-loop environments, in which the user’s joint angular velocity cannot be corrected. As the latter is essential for providing movement guidance, this paper proposes the first closed-loop system in the field of pseudo forces, using amplitude-modulated pseudo forces as haptic feedback. With this feedback, the user was assisted in moving towards a specific target angular velocity. In a human factors experiment, the amplitude-modulated stimuli were compared to constant-amplitude stimuli. The results showed that amplitude-modulated pseudo forces significantly decreased the error between the user’s and the target angular velocity when continuous movement in the desired direction was achieved. Therefore, the study demonstrated that amplitude-modulated pseudo forces can effectively guide human movement, representing an essential step towards developing a wearable movement guidance device.

Learning from Demonstration (LfD) aims to learn versatile skills from human demonstrations. The field has been gaining popularity since it facilitates transferring knowledge to robots without requiring much expert knowledge. During task executions, the robot motion is usually influenced by constraints imposed by environments. In light of this, task-parameterized (TP) learning encodes relevant contextual information in reference frames, enabling better skill generalization to new situations. However, most TP learning algorithms require multiple demonstrations in various environment conditions to ensure sufficient statistics for a meaningful model. It is not a trivial task for robot users to create different situations and perform demonstrations under all of them. Therefore, this paper presents a novel concept to learn motion policy from few demonstrations through explicitly solving reference frame weights along the task trajectory. Experimental results in both simulation and real robotic environments validate our approach.