Discussions on Inverse Kinematics based on Levenberg-Marquardt Method and Model-Free Adaptive (Predictive) Control

In this brief, the current robust numerical solution to the inverse kinematics based on Levenberg-Marquardt (LM) method is reanalyzed through control theory instead of numerical method. Compared to current works, the robustness of computation and convergence performance of computational error are analyzed much more clearly by analyzing the control performance of the corrected model free adaptive control (MFAC). Then mainly motivated by minimizing the predictive tracking error, this study suggests a new method of model free adaptive predictive control (MFAPC) to solve the inverse kinematics problem. At last, we apply the MFAPC as a controller for the robotic kinematic control problem in simulation. It not only shows an excellent control performance but also efficiently acquires the solution to inverse kinematic

Virtual Reality as a Tool for Evaluation of Repetitive Rhythmic Movements in the Elderly and Parkinson's Disease Patients

This work presents an immersive Virtual Reality (VR) system to evaluate, and potentially treat, the alterations in rhythmic hand movements seen in Parkinson's disease (PD) and the elderly (EC), by comparison with healthy young controls (YC). The system integrates the subjects into a VR environment by means of a Head Mounted Display, such that subjects perceive themselves in a virtual world consisting of a table within a room. In this experiment, subjects are presented in 1st person perspective, so that the avatar reproduces finger tapping movements performed by the subjects. The task, known as the finger tapping test (FT), was performed by all three subject groups, PD, EC and YC. FT was carried out by each subject on two different days (sessions), one week apart. In each FT session all subjects performed FT in the real world (FTREAL) and in the VR (FTVR); each mode was repeated three times in randomized order. During FT both the tapping frequency and the coefficient of variation of inter-tap interval were registered. FTVR was a valid test to detect differences in rhythm formation between the three groups. Intra-class correlation coefficients (ICC) and mean difference between days for FTVR (for each group) showed reliable results. Finally, the analysis of ICC and mean difference between FTVR vs FTREAL, for each variable and group, also showed high reliability. This shows that FT evaluation in VR environments is valid as real world alternative, as VR evaluation did not distort movement execution and detects alteration in rhythm formation. These results support the use of VR as a promising tool to study alterations and the control of movement in different subject groups in unusual environments, such as during fMRI or other imaging studies

Система процедурної генерації та уніфікації анімацій на основі інверсної кінематики

Метою роботи було створення універсального проміжного формату скелетної анімації оснований на ієрархії ланцюжків кісток і методу перетворення традиційних скелетних анімацій у цей проміжний формат, а також аналіз існуючих алгоритмів інверсної кінематики для реалізації програвання проміжного формату і можливості запису анімацій у традиційному форматі. Створена програма здатна перетворювати анімацію в проміжний формат, переносити її на іншого персонажа або додавати процедурну поведінку і записувати знову у традиційному форматі, забезпечуючи зручний інтерфейс користувача і можливість перегляду анімації на різних персонажах на усіх етапах її перетворення. Для забезпечення переносу було реалізовано кілька сучасних алгоритмів вирішення задачі інверсної кінематики. Кінцевий результат роботи у програмі являє собою анімацію у традиційному форматі, перенесену на персонажа із скелетом, що має структурні відмінності відносно скелету персонажа, для якого ця анімація створювалась.The aim of the work was to create a universal intermediate skeleton animation format based on the bone chain hierarchy and the method of converting traditional skeletal animations into this intermediate format, as well as an analysis of existing inverted kinematics algorithms for implementing intermediate format playback and the ability to record animations to a traditional format. The created program is capable of converting an animation into an intermediate format, transferring it to another character, or adding procedural behavior and recording it again as a traditional animation, providing a user-friendly interface and the ability to view animations on different characters at all stages of its transformation. Several modern algorithms for solving the inverse kinematics problem were implemented to ensure the transfer of animations. The end result of the program is an animation in the traditional format, transferred to a character with a skeleton that has structural differences with respect to the skeleton of the character for which this animation was created.Целью работы было создание универсального промежуточного формата скелетной анимации основан на иерархии цепочек костей и метода преобразования традиционных скелетных анимаций в этот промежуточный формат, а также анализ существующих алгоритмов инверсной кинематики для реализации проигрывания промежуточного формата и возможности записи анимации в традиционном формате. Созданная программа способна преобразовывать анимацию в промежуточный формат, переносить ее на другого персонажа или добавлять процедурное поведение и записывать снова в традиционном формате, обеспечивая удобный интерфейс и возможность просмотра анимации на разных персонажах на всех этапах ее преобразования. Для обеспечения переноса было реализовано несколько современных алгоритмов решения задачи инверсной кинематики. Конечный результат работы в программе представляет собой анимацию в традиционном формате, перенесенную на персонажа со скелетом, что имеет структурные различия относительно скелета персонажа, для которого эта анимация создавалась

Ring and Peg Simulation for Minimally Invasive Surgical Robot

Surgical procedures utilizing minimally invasive laparoscopic techniques have shown less complications, better cosmetic results, and less time in the hospital than conventional surgery. These advantages are partially offset by inherent difficulties of the procedures which include an inverted control scheme, instrument clashing, and loss of triangulation. Surgical robots have been designed to overcome the limitations, the Da Vinci being the most widely used. A dexterous in vivo, two-armed robot, designed to enter an insufflated abdomen with a limited insertion profile and expand to perform a variety of operations, has been created as a less expensive, versatile alternative to the Da Vinci. Various surgical simulators are currently marketed to help with the rigors of training and testing potential surgeons for the Da Vinci system, and have been proven to be effective at improving surgical skills. Using the existing simulators as a baseline, the goal of this thesis was to design, build, and test a ring and peg simulation that emulates the four degree of freedom minimally invasive surgical robot from UNL. The simulation was created in the virtual reality software platform Vizard using the python programming language. Featuring imported visual models and compound simple shape collision objects, the simulation monitors and generates a metric file that records the user’s time to task completion along with various errors. A preliminary study was done on the simulation that measured seven participant’s performance on the simulation over three consecutive attempts. The study showed that participant’s time to completion and amount of recorded errors decreased across the three trials, indicating improvement in the robot operation with use of the simulation. The validation study provided confidence in continued development and testing of the introductory surgical robot simulation trainer. Adviser: Shane Farrito

Ring and Peg Simulation for Minimally Invasive Surgical Robot

Surgical procedures utilizing minimally invasive laparoscopic techniques have shown less complications, better cosmetic results, and less time in the hospital than conventional surgery. These advantages are partially offset by inherent difficulties of the procedures which include an inverted control scheme, instrument clashing, and loss of triangulation. Surgical robots have been designed to overcome the limitations, the Da Vinci being the most widely used. A dexterous in vivo, two-armed robot, designed to enter an insufflated abdomen with a limited insertion profile and expand to perform a variety of operations, has been created as a less expensive, versatile alternative to the Da Vinci. Various surgical simulators are currently marketed to help with the rigors of training and testing potential surgeons for the Da Vinci system, and have been proven to be effective at improving surgical skills. Using the existing simulators as a baseline, the goal of this thesis was to design, build, and test a ring and peg simulation that emulates the four degree of freedom minimally invasive surgical robot from UNL. The simulation was created in the virtual reality software platform Vizard using the python programming language. Featuring imported visual models and compound simple shape collision objects, the simulation monitors and generates a metric file that records the user’s time to task completion along with various errors. A preliminary study was done on the simulation that measured seven participant’s performance on the simulation over three consecutive attempts. The study showed that participant’s time to completion and amount of recorded errors decreased across the three trials, indicating improvement in the robot operation with use of the simulation. The validation study provided confidence in continued development and testing of the introductory surgical robot simulation trainer. Adviser: Shane Farrito

Ring and Peg Simulation for Minimally Invasive Surgical Robot

Surgical procedures utilizing minimally invasive laparoscopic techniques have shown less complications, better cosmetic results, and less time in the hospital than conventional surgery. These advantages are partially offset by inherent difficulties of the procedures which include an inverted control scheme, instrument clashing, and loss of triangulation. Surgical robots have been designed to overcome the limitations, the Da Vinci being the most widely used. A dexterous in vivo, two-armed robot, designed to enter an insufflated abdomen with a limited insertion profile and expand to perform a variety of operations, has been created as a less expensive, versatile alternative to the Da Vinci. Various surgical simulators are currently marketed to help with the rigors of training and testing potential surgeons for the Da Vinci system, and have been proven to be effective at improving surgical skills. Using the existing simulators as a baseline, the goal of this thesis was to design, build, and test a ring and peg simulation that emulates the four degree of freedom minimally invasive surgical robot from UNL. The simulation was created in the virtual reality software platform Vizard using the python programming language. Featuring imported visual models and compound simple shape collision objects, the simulation monitors and generates a metric file that records the user’s time to task completion along with various errors. A preliminary study was done on the simulation that measured seven participant’s performance on the simulation over three consecutive attempts. The study showed that participant’s time to completion and amount of recorded errors decreased across the three trials, indicating improvement in the robot operation with use of the simulation. The validation study provided confidence in continued development and testing of the introductory surgical robot simulation trainer. Adviser: Shane Farrito

Ring and Peg Simulation for Minimally Invasive Surgical Robot

Surgical procedures utilizing minimally invasive laparoscopic techniques have shown less complications, better cosmetic results, and less time in the hospital than conventional surgery. These advantages are partially offset by inherent difficulties of the procedures which include an inverted control scheme, instrument clashing, and loss of triangulation. Surgical robots have been designed to overcome the limitations, the Da Vinci being the most widely used. A dexterous in vivo, two-armed robot, designed to enter an insufflated abdomen with a limited insertion profile and expand to perform a variety of operations, has been created as a less expensive, versatile alternative to the Da Vinci. Various surgical simulators are currently marketed to help with the rigors of training and testing potential surgeons for the Da Vinci system, and have been proven to be effective at improving surgical skills. Using the existing simulators as a baseline, the goal of this thesis was to design, build, and test a ring and peg simulation that emulates the four degree of freedom minimally invasive surgical robot from UNL. The simulation was created in the virtual reality software platform Vizard using the python programming language. Featuring imported visual models and compound simple shape collision objects, the simulation monitors and generates a metric file that records the user’s time to task completion along with various errors. A preliminary study was done on the simulation that measured seven participant’s performance on the simulation over three consecutive attempts. The study showed that participant’s time to completion and amount of recorded errors decreased across the three trials, indicating improvement in the robot operation with use of the simulation. The validation study provided confidence in continued development and testing of the introductory surgical robot simulation trainer. Adviser: Shane Farrito