Modular production control using deep reinforcement learning: proximal policy optimization

Journal of Intelligent Manufacturing - EU regulations on $$\textit{CO}_2$$ limits and the trend of individualization are pushing the automotive industry towards greater flexibility and robustness...     

Contributions to non-identifier based adaptive control in mechatronics

Funnel-Control (FC)–an adaptive (time-varying) MIMO/SISO control strategy–is re-introduced and its applicability introductory for position control of nonlinear, coupled (rigid) robotic systems and for speed control of nonlinear two-mass flexible servo systems is shown. Additionally Error Reference Control (ERC)–a direct derivative of FC–is established. ERC is specially designed with asymmetric boundaries and auxiliary reference, ensuring that the control error evolves within a prespecified tube (a shrinked funnel region, achieving even better tracking performance).FC and hence ERC are based on the high-gain stabilizability of minimum-phase systems with relative degree one and known sign of the high-frequency gain. Although the plant only needs to be known in structure, both concepts assure prescribed transient behavior without identification and/or parameter estimation.As most industrial applications, also the considered robotic and two-mass flexible servo systems, exhibit relative degrees greater than one, FC and ERC cannot directly be applied. Therefore a special state feedback is introduced, reducing the relative degree and retaining the minimum-phase property. The additional implementation of a nominal PI-like extension guarantees good disturbance rejection and asymptotic tracking of (constant) velocity and position reference trajectories.Simulation results for a 6-DOF Manutec r3 robot underpin and compare the achievable position control performance of one overall MIMO Funnel Controller for all joints and one SISO Funnel Controller for each joint (6 controllers). For nonlinear two-mass flexible servo systems, measurement results demonstrate the achievable load speed control performance of FC and ERC in comparison to optimal LQ state feedback.     

Laparoscopy-assisted radical vaginal hysterectomy modified according to Schauta-Stoeckel

In laparoscopy-assisted radical vaginal hysterectomy, laparoscopy is used to develop the paravesical and pararectal spaces. The cardinal ligament is isolated and cut after bipolar coagulation to the level of the deep uterine vein. By the vaginal approach, the ureters are identified before their entry into the bladder pillar. The uterine vessels are pulled down until their laparoscopically coagulated ends become visible. After incision of the vesicocervical reflection, the uterine fundus is grasped and developed (D?derlein maneuver). The lower cardinal and uterosacral ligaments are exposed by pulling the cervix and fundus uteri to the contralateral side. The cardinal and uterosacral ligaments are dissected and ligated, and the specimen is removed. We combined laparoscopic lymphadenectomy with radical vaginal hysterectomy in 33 women with cervical cancer. The mean operating time was 80 minutes for the vaginal phase and 215 minutes for the laparoscopic phase, including paraaortic and pelvic lymphadenectomy and preparation of the cardinal ligaments. Blood transfusions were necessary in four women. Three patients sustained injury to the bladder, one patient to the left ureter, and another patient to the left internal iliac vein. Repair was achieved at primary surgery for all intraoperative complications. No fistula was observed. The patients had fully recuperated after a mean of 28 days. The laparoscopy-assisted Schauta-Stoeckel approach may prove to be a safe alternative to conventional radical abdominal hysterectomy.     

The pattern of apolipoprotein B100 containing lipoprotein subclasses produced by the isolated visceral rat yolk sac depends on developmental stage and fatty acid availability

Explants of visceral rat yolk sacs from gestational days 16, 18 and 22 were used for studying developmental changes of secretion and density distribution of lipoproteins, particularly of those containing apoB. Moreover, the influence of fatty acid supply on the amount and density distribution of secreted apolipoproteins was studied on day 18 of gestation. Active lipoprotein production was observed in yolk sacs taken on days 16 and 18 of gestation. It declined considerably on day 22 of gestation in parallel with the production of total protein, triacylglycerols and cholesterol. On all gestational days, apoB floated mainly in the LDL range ( > or = 70%) with differences in the distribution pattern of LDL subclasses. The lowest density of secreted LDL was found on day 18 of gestation (peak at d = 1.025 g/ml) followed by day 16 (peak at d = 1.035 g/ml) and day 22 of gestation (peak at d = 1.045 g/ml). ApoAIV, apoE and apoAI floated exclusively in the HDL range with a peak at d = 1.089 g/ml independently of the gestational day. After incubation of yolk sacs from the 18th day of gestation with 0.4 mM or 0.8 mM oleate, the density of secreted apoB containing particles was decreased (peaks in the VLDL and IDL density range), whereas palmitate in the same concentrations caused a redistribution of secreted apoB toward higher densities (peaks at d > or = 1.032 g/ml). Taken together, the data provide evidence that the density of LDL subclasses produced by isolated yolk sacs between days 16 and 22 of gestation depended on the gestational stage. Moreover, addition of unsaturated or saturated fatty acids to the organ culture differently affected the secretory rate and the density of lipoproteins delivered by yolk sacs on day 18 of gestation.