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ABSTRACT: This paper presents a new predictive hybrid control law for a pneumatic teleoperation system using solenoid valves. Based on a predictive model of the mass flow rate of the valves, this method is used within a four-channel (4CH) bilateral control architecture for haptic teleoperation. An analysis of the controller parameters is carried out in order to achieve acceptable performances. The results show that a good accuracy in position and force tracking of the teleoperation system is obtained.
Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on; 11/2010
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ABSTRACT: This paper presents a new predictive hybrid control law for a pneumatic teleoperation system using solenoid valves. Based on a predictive model of the mass flow rate of the valves, this method is used within a four-channel (4CH) bilateral control architecture for haptic teleoperation. An analysis of the controller parameters is carried out in order to achieve acceptable performances. To evaluate the new strategy, a comparison study has been performed with a classical PWM control of a teleoperation system. The results show that the accuracy in position and force tracking in steady state but also the dynamic behavior of the pressures are better in the case of hybrid control than PWM control.
RO-MAN, 2010 IEEE; 10/2010
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ABSTRACT: This paper describes a new analysis method dedicated to the comparison of human gestures. The orientations and the positions of the gestures are first digitized using active 3D sensors and then compared to a 6-D template using curvature analysis. The proposed algorithm first starts by computing the invariant curvature of 3D position and orientation of a surgical tool using Frenet-Serret frames in 3D and quaternion space. The resulting curvature calculation is matched and compared to the template using a Dynamic Time Warping method. The proposed method is invariant to sensor position and orientation. An experimental study shows the efficiency of the new algorithm for an application in obstetrics, where the aim is to compare forceps blade placements between a senior medical doctor and a novice.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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ABSTRACT: This paper presents a new gravity compensation method for an upper extremity exoskeleton mounted on a wheel chair. This new device is dedicated to regular and efficient rehabilitation training for post-stroke and injured people without the continuous presence of a therapist. The exoskeleton is a wearable robotic device attached to the human arm. The user provides information signals to the controller by means of the force sensors around the wrist and the arm, and the robot controller generates the appropriate control signals for different training strategies and paradigms. This upper extremity exoskeleton covers four basic degrees of freedom of the shoulder and the elbow joints with three additional adaptability degrees of freedom in order to match the arm anatomy of different users. For comfortable and efficient rehabilitation, a new heuristic method have been studied and applied on our prototype in order to calculate the gravity compensation model without the need to identify the mass parameters. It is based on the geometric model of the robot and accurate torque measurements of the prototype's actuators in a set of specifically chosen joint positions. The weight effect has been successfully compensated so that the user can move his arm freely while wearing the exoskeleton without feeling its mass.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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ABSTRACT: This paper presents a new predictive hybrid control law for the control of electro-pneumatic systems using solenoid valves. The method is based on a predictive model of the mass flow rate of the valves. In order to evaluate this strategy, a comparison study in simulation has been performed with a classical PWM control for a force tracking problem. The results show that the accuracy in steady state but also the dynamic behavior of the pressures are better in the case of the hybrid control than the PWM control. The validity of the theory has been verified through simulations.
Advanced Intelligent Mechatronics (AIM), 2010 IEEE/ASME International Conference on; 08/2010
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ABSTRACT: This paper presents a method to evaluate medical gestures. The objective is to objectively assess a gesture carried out by novice doctors. The proposed method is based on the study of the curvature of the 3D gesture and provide a global performance index for one manipulation. The study of the number of peaks on the curvature indicates if the gesture is smooth or not. The application is the obstetric gestures linked to the forceps use but the method can be applied to different gestures without loss of generality. Seven residents carried out 30 forceps blade placements. The results clearly show a difference between the gestures carried out. This highlights the difficulty of the gesture according to the fetal head presentation.
Engineering in Medicine and Biology Society, 2009. EMBC 2009. Annual International Conference of the IEEE; 10/2009
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ABSTRACT: This paper presents a method to evaluate a gesture carried out by a resident obstetrician by comparing it to a gesture carried out by an expert obstetrician. The studied gesture is the forceps blade placement. Resident paths were recorded on a childbirth simulator while placing forceps blades instrumented with six degrees of freedom sensors. The path is characterized by the positions and the orientations. In this paper we particularly focus on the orientations. Forceps orientations are expressed in the quaternion unit space and the curvature of quaternion path is compared by correlation to a reference defined by an expert. Residents have been trained on a simulator and their gestures are evaluated by comparing their orientation path curvatures to reference path curvatures. Quantitative results confirm the qualitative analysis, residents become more similar to the reference while training on simulator.
Engineering in Medicine and Biology Society, 2008. EMBS 2008. 30th Annual International Conference of the IEEE; 09/2008
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ABSTRACT: This paper presents a new available feature on the childbirth simulator BirthSIM. This feature offers a risk- free training for novice obstetricians to proceed to forceps extractions. The different forces involved during deliveries are described and modeled. The choice of a control strategy in order to reproduce all these forces is explained and argued. This paper also introduces the concepts of simple and double synchronization during deliveries. Its application allows to minimize the amount of forces exerted with forceps during an instrumental delivery to make it as safe as possible. Simulations of forceps extraction carried out by two junior obstetricians are provided and analyzed. The corresponding results are compared to the literature and to the results obtained by an expert.
Robotics and Automation, 2008. ICRA 2008. IEEE International Conference on; 06/2008
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ABSTRACT: New contraceptive methods like the subcutaneous implant offers a new kind of comfort for women with an efficiency similar to the contraceptive pill. Unfortunately, the few numbers of unintended pregnancies that have been reported, are generally due to a bad insertion of the implant. In order to give more security to patients, we have designed, in close collaboration with physicians, a new kind of medical simulator. This simulator can be used for two purposes: one for training novice physicians in the correct gesture and the other for doctor certification which will help to determine if they are capable of inserting the implant in vivo. This paper describes the approach which has led to the design of this simulator. It describes its functionalities, its several components but also methods used to analyze the gesture of the implant insertion inside the patient. Finally, first experimental results are reported and discussed.
Engineering in Medicine and Biology Society, 2007. EMBS 2007. 29th Annual International Conference of the IEEE; 09/2007
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ABSTRACT: This paper presents a method to evaluate a gesture carried out by a resident obstetrician doctors by comparing it to a gesture carried out by an expert obstetrician doctors. The studied gesture is the forceps blade placement. Residents were recorded on a childbirth simulator while placing forceps blades. Their paths were compared in order to evaluate how similar they are to a reference path defined by an expert. The comparison method is developed with respect to expert requests: time independence and in considering the whole set of data and not only particular points. In order to respect these requests, the developed method lies on the correlation coefficient between the path curvatures. Residents have been trained on a simulator and their gestures were evaluated by comparing their path curvatures to reference path curvatures. Quantitative results confirm the qualitative analysis, residents become more similar to the reference while training on simulator.
Engineering in Medicine and Biology Society, 2007. EMBS 2007. 29th Annual International Conference of the IEEE; 09/2007
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ABSTRACT: Today, medical simulators are increasingly gaining attraction in clinical settings. These tools allow physicians to visualize the positions of organs, plan surgical interventions, and carry out more comprehensive post operative monitoring. A childbirth simulator provides a risk-free training and research tool for comparing various techniques that use obstetrical instruments or validating new methods. This paper presents a new teaching method to place forceps blades for obstetricians using an instrumented childbirth simulator. The proposed method is based on a physical simulator coupled with a computer graphics interface. Another aspect of this paper is to provide understanding marks to quantify the progression during a training. A first one allows to study the path in space and to quantify their repeatability, a second one allows to compute the error to a reference gesture defined by an expert. Both marks are complementary. Two novices were trained and they manage to have a more repeatable gesture and above all to become closer to a reference gesture, i.e. to reduce the injury linked to the use of forceps during instrumental deliveries.
Robotics and Automation, 2007 IEEE International Conference on; 05/2007
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ABSTRACT: This paper presents some new automatic procedures for the BirthSIM childbirth simulator. BirthSIM is able to simulate the uterine contractions and the mother's voluntary efforts, this enables the operator to synchronize these two types of efforts during a normal childbirth, or to synchronize these two efforts with the operator's tractive instrumental effort during childbirth using obstetric instruments. One originality of the BirthSIM simulator is to allow the medical team to acquire a better understanding of the application of these two synchronization concepts. With the aim of implanting various childbirth procedures, four control algorithms and switching algorithms are used to control successively: force, position, force-velocity or force-position. These control algorithms are important to produce the movement of the head, the mother's natural contractions and the mother's pushing action. Different childbirth cases are simulated using an electropneumatic system. The validity of the proposed control method for simulating childbirth modes has been evaluated by an expert obstetrician
Intelligent Robots and Systems, 2006 IEEE/RSJ International Conference on; 11/2006
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ABSTRACT: This paper presents work resulting from a collaboration between obstetricians and researchers. It shows the benefits from the use of an instrumented childbirth simulator for the training of obstetricians and midwives. This new tool allows to surpass the constraints linked to the traditional training in a childbirth ward. This simulator training is designed to complete the traditional training used in teaching hospitals. Such a training allows residents to acquire a beginning experience before training in a childbirth ward but it also allows instructors to improve the teaching gestures without constraints. A clinical study of the forceps blades placement gesture with several residents who trained on a childbirth simulator is made. The results clearly show the progress in the obstetric gestures of all the residents who have used the simulator
Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE; 10/2006
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ABSTRACT: Our recent results indicated that the major proteins of bovine seminal plasma (collectively called BSP proteins) stimulate cholesterol efflux from fibroblasts and that this process shows many differences compared to the efflux induced by apolipoprotein A-I (apoA-I)-containing lipoproteins. The present study was undertaken to investigate the BSP-mediated efflux mechanism. Compared to the slow and constant rate of cholesterol efflux induced by apoA-I-containing lipoproteins, the BSP proteins stimulated a rapid efflux that gradually reached a plateau. The addition of purified BSP proteins after the establishment of the plateau resulted in a further cholesterol efflux indicating that cellular cholesterol was still available for efflux. Incubation of unlabeled fibroblast culture with the spent medium containing BSP-generated lipid ([(3)H]cholesterol) particles obtained after the establishment of the plateau did not result in any cholesterol influx. Therefore, the plateau did not correspond to an equilibrium of the radiolabel between the medium and the cells but rather to a saturation of the efflux particles with cholesterol. Numerous studies have indicated that the cholesterol efflux induced by apoA-I-containing lipoproteins involves cell-surface receptor, caveolae and intracellular cholesterol mobilization. Therefore, we investigated these characteristics for the BSP-mediated cholesterol efflux. Binding of BSP proteins to cells (evaluated by immunoblotting) reached saturation rapidly and remained constant thereafter. However, after several washings the cell-bound BSP proteins were unable to promote significant cholesterol efflux. Both results indicate no correlation of cholesterol efflux with cell binding. Moreover, in comparison to apoA-I-mediated cholesterol efflux, BSP-mediated efflux was not abolished at temperatures below 22 degrees C indicating that the BSP-induced cholesterol efflux does not involve intracellular cholesterol mobilization. High-density lipoprotein- and apoA-I-mediated cholesterol efflux was inhibited by preincubating fibroblasts with progesterone, whereas the cholesterol efflux by BSP proteins was not, indicating that cell-surface caveolae do not participate in BSP-mediated cholesterol efflux. Our results indicate that the mechanism of cholesterol efflux by BSP proteins is unidirectional and is strikingly different from that mediated by apoA-I-containing lipoproteins.
Biochimica et Biophysica Acta 09/2000; 1487(1):24-32. · 4.66 Impact Factor
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ABSTRACT: Several studies have shown that sperm capacitation was accompanied by a change in the lipid composition of the sperm membrane. In cattle, the major proteins of (bovine)seminal plasma (BSP proteins: BSP-A1/A2, BSP-A3, and BSP-30-kDa) potentiate sperm capacitation induced by high-density lipoprotein (HDL). Our recent studies indicate that these proteins and HDL stimulate sperm cholesterol efflux during capacitation. In order to gain more insight into the mechanisms of BSP-mediated sperm capacitation, we studied whether or not BSP proteins induce phospholipid efflux from epididymal sperm membrane. By direct determination of choline phospholipids on unlabeled epididymal sperm, the results show that sperm incubated in the presence of BSP-A1/A2 protein lost 34.4% of their choline phospholipids compared with the control (11.5%). Similar results were obtained using labeled epididymal sperm. Labeling was carried out by incubating washed epididymal sperm for 1 h with medium containing [(3)H]palmitic acid. The majority of the label was incorporated into sperm phosphatidylcholine. Studies of sperm phospholipid efflux were done by incubating the labeled sperm with purified BSP proteins, delipidated BSA, or bovine seminal ribonuclease (RNase, control protein). When labeled ([(3)H]phospholipid) epididymal sperm were incubated with BSP proteins (20-120 microg/ml) for 8 h, the sperm lost [(3)H]phospholipid in a dose-dependent manner (maximum efflux of approximately 30%). After the incubation with BSP proteins, the efflux particles were fractionated by size-exclusion chromatography. Analysis of the fractions obtained showed that the [(3)H]phospholipid was associated with BSP proteins. BSA (6 mg/ml) stimulated a specific phospholipid efflux of approximately 22%. In contrast, bovine RNase (120 microg/ml) did not stimulate phospholipid efflux. These results indicate that BSP proteins participate in the sperm cholesterol and phospholipid efflux that occurs during capacitation.
Biology of Reproduction 10/1999; 61(3):590-8. · 4.01 Impact Factor
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ABSTRACT: We reported recently that the choline phospholipid-binding proteins (BSP-A1/-A2, BSP-A3 and BSP-30-kDa) of bovine seminal plasma (BSP) stimulate cholesterol and choline phospholipid efflux from fibroblasts. In this study, we characterized the lipid efflux particles generated by BSP proteins. The density gradient ultracentrifugation of the efflux medium from radiolabeled fibroblasts incubated with BSP proteins showed a single peak of [3H]cholesterol between density (d) 1.12 and 1.14 g/ml, which is in the range of high-density lipoproteins. Size-exclusion chromatographic and immunoblot analysis revealed that the efflux particles have a large size equal to or bigger than very low-density lipoproteins and contained BSP proteins. Lipid analysis of density gradient and gel filtration fractions from efflux medium of simultaneously labeled fibroblasts ([3H]cholesterol and [3H]choline) incubated with BSP proteins showed that the efflux particles were homogeneous and composed of cholesterol and choline phospholipids. The lipid particles contained BSP proteins, cholesterol and choline phospholipids in molar ratio of 0.05:1.21:1, respectively. Agarose gel electrophoresis showed that the BSP-generated lipid particles had a gamma migration pattern which is slower than low-density lipoproteins. The sonication of cholesterol and BSP proteins followed by gel filtration chromatographic analysis indicated no direct binding of cholesterol to BSP proteins. These results taken together indicate that BSP proteins induce a concomitant cholesterol and choline phospholipid efflux and generate large protein-lipid particles.
Biochimica et Biophysica Acta 06/1999; 1438(2):175-84. · 4.66 Impact Factor
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ABSTRACT: Bovine seminal plasma (BSP) contains a family of phospholipid-binding proteins (BSP-A1/-A2, BSP-A3 and BSP-30-kDa, collectively called BSP proteins) that potentiate sperm capacitation induced by high-density lipoproteins. We showed recently that BSP proteins stimulate cholesterol efflux from epididymal spermatozoa and play a role in capacitation. Here, we investigated whether or not BSP proteins could stimulate cholesterol and phospholipid efflux from fibroblasts. Cells were radiolabeled ([3H]cholesterol or [3H]choline) and the appearance of radioactivity in the medium was determined in the presence of BSP proteins. Alcohol precipitates of bovine seminal plasma (designated crude BSP, cBSP), purified BSP-A1/-A2, BSP-A3 and BSP-30-kDa proteins stimulated cellular cholesterol and choline phospholipid efflux from fibroblasts. Efflux mechanistic differences were observed between BSP proteins and other cholesterol acceptors. Preincubation of BSP-A1/-A2 proteins with choline prevented cholesterol efflux, an effect not observed with apolipoprotein A-I. Also, the rate of BSP-induced efflux was rapid during the first 20 min, but leveled off thereafter in contrast to a relatively slow, but constant, rate of cholesterol efflux mediated by apolipoprotein A-I, apolipoprotein A-I-containing reconstituted lipoproteins (LpA-I) and high-density lipoproteins. These results indicate that fibroblasts are a good cell model to study the mechanism of lipid efflux mediated by BSP proteins.
Biochimica et Biophysica Acta 05/1999; 1438(1):38-46. · 4.66 Impact Factor
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ABSTRACT: Capacitation is an important process in bovine sperm maturation and is an obligatory step prior to fertilization. Two capacitating agents, namely heparin and high-density lipoprotein (HDL), have been shown to induce sperm capacitation. A family of major proteins of bovine seminal plasma designated BSP-A1/A2, BSP-A3, and BSP-30 kDa (collectively called BSP proteins) bind to the sperm surface upon ejaculation via their membrane choline phospholipids. Our previous studies with bovine epididymal sperm showed that BSP proteins potentiate sperm capacitation induced by heparin and HDL. This study was undertaken to clarify the mechanism of capacitation induced by heparin and HDL in the presence of BSP proteins. Washed bovine ejaculated sperm were incubated with heparin (12 microg/ml) or HDL (10-160 microg/ml) in the presence of polyclonal antibodies against purified BSP proteins (anti-BSP proteins). The percentage of capacitated sperm was evaluated after the induction of the acrosome reaction (AR) with lysophosphatidylcholine. When sperm were incubated for 5 h with heparin and anti-BSP proteins (40 microg/ml), the AR level was not significantly different from control levels (16. 8 +/- 0.9% vs. 12.9 +/- 0.9%). In contrast, incubation of sperm for 8 h with HDL and anti-BSP proteins did not inhibit the AR (42.4 +/- 1.1% vs. 17.1 +/- 1.6 for the control samples). We also investigated the effect of heparin and HDL on protein tyrosine phosphorylation associated with capacitation. The tyrosine phosphorylation of a group of proteins was increased in the presence of heparin. However, HDL did not significantly stimulate protein phosphorylation. The increase in phosphorylation was correlated with an increase in the AR after the incubation with heparin but not with HDL. These results indicate that heparin and HDL mediate capacitation via different mechanisms.
Biology of Reproduction 02/1999; 60(1):169-75. · 4.01 Impact Factor
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ABSTRACT: One of the hypotheses to explain the mechanism of capacitation involves the loss of sperm membrane cholesterol. Here, we studied whether or not the major proteins of bovine seminal plasma designated as BSP-A1, -A2, -A3, and -30-kDa (collectively called BSP proteins), which are implicated in sperm capacitation, induce cholesterol efflux. When epididymal sperm were labeled with [3H]cholesterol and incubated with bovine seminal plasma (0.05-2%) or BSP proteins (20-120 microg/ml) for 8 h, the sperm lost [3H]cholesterol (3.6-fold and 3-fold, respectively). The same results in the presence of BSP-A1/-A2 were obtained (3.5-fold) by direct determination of cholesterol on unlabeled epididymal sperm. Analysis of efflux particles by ultracentrifugation on a sucrose gradient revealed a single symmetrical peak of radioactivity at 1.14 g/ml. Immunoblotting of the fractions obtained from size-exclusion chromatography of the efflux particles showed that a portion of the BSP proteins were associated with [3H]cholesterol. Heparin (12 microg/ml) alone did not stimulate cholesterol efflux. In contrast, high-density lipoprotein (HDL, 100 microg/ml) alone stimulated cholesterol efflux up to 3.1-fold after 8 h. When labeled epididymal sperm were preincubated for 20 min with BSP-A1/-A2 (120 microg/ml), washed, and incubated with HDL (100 microg/ml) for 8 h, the total cholesterol efflux of the sperm suspension was 51.8 +/- 5.0% compared to 39.3 +/- 1.2% when HDL alone was used. These results indicate that BSP proteins and HDL play an important role in the sperm sterol efflux that occurs during capacitation. Furthermore, the heparin-induced sperm capacitation did not involve the efflux of sperm membrane cholesterol.
Biology of Reproduction 11/1998; 59(4):768-76. · 4.01 Impact Factor
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ABSTRACT: Bovine seminal plasma contains a family of major proteins (collectively called 1BSP proteins) that potentiate sperm capacitation by binding to capacitation factors such as heparin and by stimulating sperm membrane cholesterol efflux. Here, we investigated the structure-function relationship of type II domains of BSP proteins. We isolated from a tryptic digest of citraconylated BSP-A1/-A2 proteins the intact second type II domain (domain b or Db). Similar to native protein, Db bound to heparin-Sepharose, p-aminophenylphosphorylcholine-Agarose and liposomes containing phosphatidylcholine. When assessed for biological function, Db did not stimulate cholesterol efflux from human fibroblasts, a cell model for lipid efflux studies, and from bovine spermatozoa, or potentiate bovine sperm capacitation induced by heparin and high-density lipoproteins. Therefore, type II motifs of BSP proteins represent binding units for sperm membrane choline phospholipids and heparin but the second type II domain of BSP-A1/-A2 alone is not sufficient to stimulate lipid efflux nor is sufficient to potentiate bovine sperm capacitation. Thus, the presence of both type II domains in BSP proteins is essential for the expression of functional properties, namely lipid efflux and sperm capacitation.
Biochemical and Biophysical Research Communications 06/1998; 246(1):148-54. · 2.48 Impact Factor
