In recent years, with the combination of tissue engineering and additive manufacturing technologies, the possibility of fabricating scaffolds with porosity and complex structure has been improved. Since the properties of most biomaterial inks are influenced by temperature and thereby affect the quality of the scaffolds, a controlled printing environment is very important. This study focuses on temperature monitoring from the nozzle to the working platform. A compact heating jacket is developed to heat the needle and sense its temperature inside the nozzle. It makes it very different from common cartridge heating mechanisms. Moreover, a semi-closed printing environment composed of an air curtain and temperature circulation device is developed to create a stable cooling environment. It improves the uniformity of the work platform and increases by 50% the cooling time efficiency. To demonstrate the robustness for a wide range of temperatures, this study presents two experiments of printing two biomaterial inks at body and low temperatures, respectively.

Nano-robotic systems based on Piezoelectric StickSlip (PSS) actuators have become increasingly popular in research and industry for semi-automated and automated tasks at small scales. For an efficient use of PSS actuators, a series of research have been fulfilled on design process, dynamic modeling, driving methods and position control. However, there have been very few investigations on velocity control of PSS actuators. Velocity control is important to enable the nano-robotic system to generate a smooth and efficient motion and to avoid the undesired inertial shock of the end effector. This paper deals with velocity characterization and control strategies for nano-robotic systems based on PSS actuators. The range of achievable velocities on PSS actuators is studied in air and vacuum environments. This analysis allows the definition of a detailed map of the velocity characteristics in forward and backward directions of motion. Velocity control strategies are then studied based on an instantaneous velocity feedback and an average velocity feedback. Results of the proposed method show the first experimental demonstration of velocity control for PSS actuators in medium and high speed configurations opening new perspectives on the use of nano-robotic systems in dynamic automated tasks.

This work deals with a Conducting-Interpenetrating Polymer Network (C-IPN). The C-IPN exhibits very interesting and promising properties which can make it suitable for applications in robotics as a tool to perform tasks in the fields of manipulation, grasping or force measurement. It is known in the literature that such C-IPN may be actuated and bended to interact with other objects. Some of them can also be used as sensors to characterize the interaction. In this paper, we show that actuation and sensing can be performed at the same time. Moreover, we propose analytical models which can be useful for future work to process the C-IPN output and to control them. All results are verified with experimental data.

The last couple of years, the vehicle industry tends to increase the performance of lights based on led technologies. Nowadays, led systems are used as a standard by motor vehicles manufacturers. Led lights present higher reliability and are more flexible regarding design or power adjustments. Furthermore, led systems are also very convenient for intensity modulation used in telecommunication fields. We developed a very simple data transmission system based on led lights which is highly robust for short or medium distances ± from a few meters up to 15 meters. This visible light communication is dedicated to the cooperation between vehicles and road infrastructures to enhance traffic security. This paper explains the choices and first results on the data transmission performances. In this paper, we present a first prototype of our system and experimental results.

Molecular interactions typically have a high dynamic range (HDR), combining short-range stiff repulsive effects with long-range, soft attractive and repulsive terms. As a result, faithful haptic rendering of such molecular interactions is both important and difficult, in particular in applications where the precise perception of molecular forces is necessary (e.g. in molecular docking simulations). Traditionally, teleoperation coupling using constant gain control schemes have limited applications since they are unable to transmit to users low attractive forces without truncating repulsive ones. Furthermore, constant scaling displacement induces either instability or time-consuming experiments (displacements are slow), which deteriorates the ease of manipulation. In this paper, we describe a variable gain haptic coupling method specifically designed to render high dynamic range (molecular) forces. The proposed method is evaluated by user tests on an experiment involving two water molecules. We observe that variable force amplification is widely appreciated, whereas variable displacement scaling is appropriated only for users familiar with haptic manipulation. A complex experiment on a HIV molecule is carried out using this variable gain system. Advantages and limitations of this approach are discussed.

This paper deals with the problem of bilateral haptic control in nanorobotics. At this scale, a human operator cannot interact directly with objects. He needs special tools manipulated through robotic systems. Therefore, force feedback devices are the only solution to provide him a sense of touch. However, the quality of the rendering strongly influences his ability to perform a given task. Stability is the main requirement that the system must fulfil to be usable. As the choice of the controller and its tuning are critical issues, a general method to tune the parameters of two haptic controllers is presented. A theoretical study is carried out and the methodology is validated with an experiment composed of several phases with high dynamic phenomena. Intrinsic limitations of the two controllers are also pointed out.

This paper presents a 2D teleoperation task at microscales with force feedback. At this scale, two major problems arise while performing manipulation tasks: the lack of 3D real time visual feedback, and the difficulty to determine the interaction forces. Therefore, indications must be provided to help the user perform a given task. In this paper, we provide the user with intuitive force feedback, to improve objects' manipulation using a haptic device. Our platform is composed of a tipless beam manipulator, which is deformed when forces are applied to it. These deformations are measured using a laser. The force information we provide to the user is based on the raw beam's deformation measurement, and mechanical properties of the probe. It does provide the operator with indications about the interaction forces. This approach is validated by performing lateral and longitudinal rolling operations using microspheres with a radius of 25-micrometers. 2D rolling telemanipulation at microscale with force feedback is successfully demonstrated.

In this paper, a new tool dedicated to the analysis and the conception of molecules is presented. It is composed of an adaptive simulation software and a haptic device used to interact with molecules while feeling either the forces applied by the environment or the internal forces. The adaptive articulated body algorithm allows fast simulations of complex flexible molecules. To handle the coupling with the force feedback device, two different control schemes designed for nanoscale applications and providing high transparency rendering are proposed and compared.

The proposed robotic system provides the surgeon with an augmented sensation of the interaction forces between the instrument and the organ. Such a system aims at increasing the surgeon's dexterity for tasks requiring that only small forces be applied on the organ (eg. for micro-surgery). In the proposed setup, the surgeon manipulates a handle mounted on the instrument. This is a comanipulation system because the surgeon and the robot simultaneously manipulate the instrument. The proposed control scheme allows an augmented force control: the control law ensures that the instrument applies on the organ the same forces that the surgeon applies on the handle but decreased by a scale factor. As a consequence, the forces sensed by the surgeon are the forces between the instrument and the organ amplified by a scale factor. This control scheme is proved stable thanks to a passivity study. Indeed, passivity analysis is a useful tool for the stability analysis of a robot interacting with the environment. Experimental results are presented on a robot dedicated to minimally invasive surgery.

This paper presents a force feedback control scheme for the compensation of periodic motions of organs induced by respiration or heartbeat in minimally invasive robotized surgery. It applies surgical tasks involving a contact between an instrument and a moving organ. It is well known that conventional force control allows for compensating the motion of the environment thanks to its natural disturbance rejection capabilities. However, as experimentally evidenced in the first part of this paper, bandwidth limitations do not allow for exact disturbance rejection. Therefore, in addition to a conventional inner force feedback control loop, an outer control loop based on iterative learning control (ILC) is implemented. It is aimed at compensating the physiological motions, based on the hypothesis that the disturbance is periodic. The transient performances of this ILC controller are improved thanks to a wavelet transform-based approach and conclusive experiments are finally presented, evidencing that the tracking performance under cyclic disturbances is significantly improved.

In this article, the problem of force feedback control of kinematically constrained manipulators (KCMs) is considered. For these robots, we show that the force component selection approach is not appropriate in general to solve the force control problem. Moreover, by formulating the problem in the joint space, we show how to properly design a stable force controller for KCMs subject to arbitrary external forces applied to their end-effector. Experimental results with a kinematically constrained laparoscopic comanipulator illustrate these propositions