BoB – biomechanics in MATLAB

Biomechanics is a maturing discipline with numeric analysis of kinematic and kinetic data becoming widespread within academic research institutions and commercial organisations. Many engineers and scientists engaged in biomechanical analysis already routinely use MATLAB as it provides an environment that is productive for a broad range of analysis, facilitates rapid code development and provides sophisticated graphical output. Therefore, a biomechanical package which is based within the MATLAB environment will be familiar to many analysts and will inherit much of the analysis capabilities of MATLAB. This paper describes BoB (Biomechanics of Bodies) which is a biomechanical analysis package written in MATLAB M-code, capable of performing inverse dynamics analysis, using optimization methods to solve for muscle force distribution and produces sophisticated graphical image and video output.

Stress analysis of osteoporotic femur

Osteoporosis and degenerative diseases cause low bone mass that increases fracture risks. This study presents the modelling of osteoporotic femur by employing finite element method (FEM). The loading of femur using FEM tools was performed. The level of degradation was modelled by changing the thickness of cortical shell and using power-law equations, which determine the dependence between apparent density of cancellous bone and its mechanical properties. Obtained results could be useful for both medical diagnosis and bone health check.

The study of extraneous conditions that affect tilt-based pointer movements

Introduction: With the rapid evolution of mobile devices, there is also a tremendous growth in their applications. This triggers new research on more efficient techniques of humancomputer interaction. To point at an object of interest seen on the screen of a mobile device, various new methods were suggested recently. Methods: This paper presents the results of a user study that employed tilting as a technique for entering text. The independent variables in the user study were mobility (sitting, walking, sitting in the moving bus) and keyboard size (5×3, 10×4). The experiment involved 50 participants aged from 22 to 65. Results: In the walking condition, it took on average 11.3% more time for participants to complete the task compared to the sitting condition with 5×3 keyboard, and 45.1% more time compared to the sitting condition with 10×4 keyboard. Keyboard size had a marked influence on task completion time. In addition, task completion time while traveling by bus was 3.2% longer than that observed for the walking condition with 5×3 keyboard. Surprisingly, task completion time with 10×4 keyboard while traveling by bus was 10.4% shorter compared to the walking condition. Error rate and movement efficiency were investigated additionally to find out the explanation for such performance data.

The supporting method for automatic diagnosis of prostatic hypertrophy

In the paper numerical algorithms used in the automatic diagnosis of prostatic hypertrophy are presented. The liquid flow during urination was applied as a signal that describes the condition of prostate. In order to register the signal, the uroflowmeter was used. Patients were included in a two-step procedure. In the first step, an analysis of signal characteristics, such as maximum and the mean value with the use of Liverpool Nomogram, were performed. Then, the signal was tested for the presence of oscillation. For this purpose, an algorithm that generates the reference signal was created. Moreover, the similarity waveform was investigated with the help of the integral index. The diversity of signals indicated the presence of anomalies and had an impact on the final classification of the patient.

AFM investigation of hyaline cartilage’s surface destruction

Introduction: Osteoarthritis is a chronic, progressive disease. The aim of this paper is presenting the AFM investigation of cartilage in relation to the assessment of degenerative changes in the surface of hyaline cartilage. It can be useful in choosing the most effective methods of therapy. Methods: Samples were taken from the cartilage surface of the femoral head after its removal during total hip arthroplasty. Images of the surface of the sample were obtained using an optical microscope equipped with a digital video camera, in the reflected light and by atomic force microscopy. Results: The longitudinal orientation of the collagen fibers and sub-fibers beams on the surface, up to a diameter of 50 nm are identified in non-destroyed area sites. Conclusions: Images of the destroyed areas displaying separately passing collagen fibers, strongly exposed to the surface: the size measured and found substructure.

Estimation of temporal gait parameters of multiple sclerosis patients in clinical setting using inertial sensors

Multiple sclerosis (MS) is the most frequent neurological disease causing permanent disability in young adults. Subtle walking difficulties, such as reduced walking speed, step length, cadence and increased step width can be detected at an early stage of the disease. Main goal of this research is by using non-invasive wireless inertial sensors measure gait of MS patients in clinical setting and extract temporal biomechanical parameters that would allow objectively evaluate level of disability in MS patients. Analysis of 25-Foot walk showed that the duration of stance phase is approximately 1.6 times greater in MS group than in healthy control group, while the duration of swing phase in MS group is 1.3 times longer. In general, the MS patients are walking approximately 1.6 times slower.

Estimation of the parameters of barbell’ lifting law of motion

Characteristic points of the law of motion were determined based on the results of experimental study on the velocities and accelerations of the lifted barbell. Relationship between the height of the athlete, lifted weight, maximal velocity and acceleration was estimated analytically. It was shown, that at the initial time moment the athlete must apply approximately 1,5 times larger force than lifted weight. The values of the parameters of the barbell’ law of motion and lifting force approximate law of change were estimated.

Assessment of the effectiveness of pressure ulcer care

The article deals with the external and internal factors influencing development of pressure ulcers and the effectiveness of their care. The patients were assessed according to their age, gender and changes in their condition. The modified Norton Scale was used to assess the effectiveness of pressure ulcer care. It has been established that internal factors increase the risk of developing pressure ulcers. The effectiveness of pressure ulcer care is promoted by pressure ulcers preventative measures, medicines and skin hygiene.

Numerical modelling of the forklift tip-over to test effectiveness of the safety components

Forklift overturning with its operator is the most common and dangerous type of an accident involving internal transport. The forklifts are equipped with safety components to avoid, or reduce the effects of forklift tip-over. However, there is very few information on the effectiveness of such systems. The aim of the research was to evaluate their effectiveness with the use of numerical simulation. The study relied on carrying out numerical simulations of forklift overturning with its operator. Active human body model was used in the research. Human body output parameters, e.g. forces and accelerations of the head and neck were used to estimate injuries sustained by an operator. The effectiveness of the safety components was assessed on the basis of estimated injuries.

Geometry and mechanical function of multijoint extremities from mammals to insects: towards biomimetic design of robotic arm

Biomechanics of legs of different families of insects is studied. Geometry of different pairs of legs designed for walking, running, swimming, digging and other tasks has been measured on entomological collections. Relationships between the lengths of three main segments (femur, tibia, tarsus) as well as their smaller segments (if any) have been studied. It is shown the cursorial and fossorial legs satisfy the same nondimentional relationships in the insects of different size, habitat and evolutionary age, while the saltatorial, nanatorial and raptoridal legs possess different types of relations. Application of the nature inspired design to engineered macro and micro manipulators and robotic systems is discussed.