Modeling and control of a two-arm elastic robot in gravity

This thesis develops and experimentally verifies a model of a two arm robot with highly elastic arms. The model is later used in this research to evaluate control algorithms. The model includes the effects of gravity. The dimensions of the arms are chosen to maximize the coupling between the flexible and large scale motion of the robot. The model is then linearized and a new analytical solution is presented for the natural frequencies and mode shapes of the robot at given equilibrium positions. This analytical solution is then compared to the assumed mode shape solutions to determine the accuracy relative to the number of assumed modes included in the model. An experimental test rig is built and tests are conducted to verify the model. A number of different amounts of end mass and torsional stiffness at the joints are used during the validation. For 12 cases tested, the measured first four natural frequencies are within ±7% of the frequencies predicted by the model with an average error of only 2.89%. Finally, the model is used to design a control algorithm for end effector control of the robot using a torque input at each of the two joints. An optimal control algorithm developed using LQR with the prescribed degree of stability method results in effective end effector control with short response time and little overshoot

Modeling and control of a two-arm elastic robot in gravity

This thesis develops and experimentally verifies a model of a two arm robot with highly elastic arms. The model is later used in this research to evaluate control algorithms. The model includes the effects of gravity. The dimensions of the arms are chosen to maximize the coupling between the flexible and large scale motion of the robot. The model is then linearized and a new analytical solution is presented for the natural frequencies and mode shapes of the robot at given equilibrium positions. This analytical solution is then compared to the assumed mode shape solutions to determine the accuracy relative to the number of assumed modes included in the model. An experimental test rig is built and tests are conducted to verify the model. A number of different amounts of end mass and torsional stiffness at the joints are used during the validation. For 12 cases tested, the measured first four natural frequencies are within ±7% of the frequencies predicted by the model with an average error of only 2.89%. Finally, the model is used to design a control algorithm for end effector control of the robot using a torque input at each of the two joints. An optimal control algorithm developed using LQR with the prescribed degree of stability method results in effective end effector control with short response time and little overshoot.</p

Laparoscopic correction of transverse testicular ectopia with persistent Müllerian duct syndrome

Transverse testicular ectopia (TTE) with persistent Müllerian duct syndrome (PMDS) is a rare genitourinary anomaly. Herein, we report a case of TTE with PMDS corrected laparoscopically. An 11-month old male patient visited our hospital with swelling of the right inguinal area. The right testis was palpable in the right scrotum while left testis was not in the left scrotum. During laparoscopic exploration, the left testis was found around the right inguinal area, with the left spermatic cord across the pelvic cavity from left side. When the left testis was pulled, a tubular structure, Müllerian duct remnant, and the right spermatic cord came into the abdominal cavity. The Müllerian duct seemed like a uterus was located between both vas deferens. We divided it because the length of the bilateral vas deferens was not sufficient for orchiopexy. After laparoscopic right orchiopexy and left trans-scrotal approach orchiopexy, bilateral inguinal herniorrhaphy was performed laparoscopically

A large intrahepatic duodenal duplication cyst in a 3 year-old girl

Duodenal duplication cyst consists 6% of alimentary tract duplications and the prevalence is estimated to be less than 1 per 100,000 live births. This report is the first case report in a pediatric patient. A 19-month-old female patient was detected with a 5.2 cm sized intrahepatic cystic lesion in her follow-up ultrasonography examination for hydronephrosis. In her regular check-up, findings suggestive of food materials were detected inside the cyst. Further evaluation showed a 7 cm sized cyst located inside segment IV of the liver, connected to the duodenal bulb with a possibility of biliary communication. On exploration, duodenal duplication cyst with a 1.5 cm long stalk starting from the duodenal bulb to the hilum of the liver was identified. Due to its sophisticated location and possible communication with the biliary tree, Roux-en-Y cystojejunostomy was performed after resecting the stalk. The histopathologic finding of the stalk showed serosa, muscle, submucosa and duodenal mucosa which suggested its duodenal origin. The patient has been followed up without any complications for 7 months

Perforated Meckel's diverticulum in omphalocele

Meckel's diverticulum is a rare condition in neonates with reports of concurrent Meckel's diverticulum and omphalocele being few. Herein, we present a case of omphalocele associated with perforated Meckel's diverticulum

The Optimal Timing of Enterostomy Closure in Extremely Low Birth Weight Patients for Acute Abdomen

Abstract There are few reports on enterostomy closure (EC) timing for acute abdomen in extremely low birth weight (ELBW) patients. We retrospectively reviewed ELBW patients who underwent enterostomy formation (EF) and subsequent EC. We investigated baseline characteristics, surgical outcomes, and follow-up data of 55 patients and analyzed optimal timing by age at EC, enterostomy duration, and body weight (Bwt) at EC. The minimum p-value approach (MPA) using the Chi-squared test was used to determine each cut-off value. Mean gestational age was 25+3 weeks, while mean age and Bwt at EF were 10 days and 660 g. Enterostomy duration and Bwt at EC were 102 days and 2400 g. Fourteen surgical complications were related to EC. The MPA identified a cut-off of 2100 g (p = 0.039) at EC but no significant cut-off age or enterostomy duration. The 18 patients 2100 g group (66.7% vs 10.8%, p < 0.001). No other characteristics were significantly different. Operation time, ventilator period, hospital stay, parenteral nutrition duration, and full feeding day were significantly longer in <2100 g patients. Follow-up Bwt did not differ (11.55 kg vs 13.95 kg, p = 0.324). Our findings suggest EC can be safely performed when Bwt is over 2100 g

Clinical Course of Bacillus Calmette-Guerin Lymphadenitis

Bacillus Calmette-Guerin (BCG) vaccination can cause lymphadenitis. The purpose of the current study was to describe patient characteristics and clinical courses of lymphadenitis associated with BCG vaccination. A total of 171 patients who visited a tertiary hospital with a diagnosis of BCG-associated lymphadenitis between January 2012 and June 2017 were included. The diagnostic criteria were a history of BCG vaccination on the symptomatic side, absence of tenderness and raised temperature over the swelling, absence of fever and constitutional symptoms, and isolated axillary (or supraclavicular/cervical) lymph node (LN) enlargement. Treatment strategies included observation, antibiotics, incision and drainage or needle aspiration (I&amp;D/NA), and surgical excision. The median follow-up period was 40 days (range 1&ndash;1245 days). The median age at the first visit was 5.5 months (range 0.9&ndash;83.7 months). The most common location was the axilla (81.3%). The respective numbers of patients managed via observation, I&amp;D/NA, antibiotics, and surgical excision were 99, 47, 5, and 20. LNs were significantly more enlarged in the I&amp;D/NA group than in the antibiotics group and the observation group. The respective times taken for residual lesions to reduce to &lt; 20% were approximately 3 months, 4 months, and 5 months in the antibiotics, observation, and I&amp;D/NA groups. The surgery group had significantly fewer residual lesions than the observation group at the last visit, but there was no significant difference in current residual lesions between the groups. LNs were significantly larger in the I&amp;D/NA group. The surgery group exhibited the least residual lesions at the last visit, but there was no significant difference in current status