Modeling, Design and Control of Miniaturized Soft Robots – MiniSoRo

The approach proposed in MiniSoRo is the development of original methods for designing, modelling and controlling miniaturized parallel robots composed of rigid and flexible elements with large deformations, as well as the development of methods to control them.
Parallel kinematics will be adopted to be able to miniaturize the robot structures and place all the actuators at the robot’s base. The result will be a light structure that can reach high bandwidths. New parallel kinematic architectures will be adopted to integrate grasping as an internal mobility of the robot, which will also be actuated from the robot’s base.
Soft joints or flexible links (continuum robot) will be used in micro-parallel mechanisms instead of classical mechanical joints in order to: i) eliminate the mechanical defects such as backlashes; ii) develop highly compact mechanisms and; iii) cover a large workspace in translation and rotation.
MiniSoRo will use micro-fabrication techniques in clean room associated with compact instrumented and piezoelectric actuators with a high bandwidth. The deformable elements will probably be PDMS as soft joints or Nitinol tubes as flexible links.

MiniSoRo will develop modeling, design and control methods of miniaturized deformable parallel robots with a configurable platform as well as methods to fabricate them.
The integrated miniaturized robot is expected to have outstanding performances compared to the state of the art. In addition to its Degrees of Freedom (DoF), the proposed robots will be able to grasp and manipulate micro/nano-objects in the 3D space (translations and rotations) thanks to a configurable platform. Flexible links or soft joints will be used to increase the motion range of the robot and eliminate backlash. In addition, all the sensors and actuators will be integrated which will produce a highly compact robot that can reach a very throughput and precisions and will be able to achieve large displacements in translation and rotation compared to the existing microrobots.
Such a miniaturized robot is expected to be the only robot in the world that combines such performances (compactness, accuracy and speed) and will push up several performances criteria at a time.
The technological contributions are: i) the development of technologies and processes for the fabrication and integration of soft/flexible elements into submillimetric and micrometric structures and; ii) the integration of sensors (strain gauges deposited in cleanroom) to measure the positions and the torques at the robot base and actuators (piezoelectric) into the robotic structures.

The expected features and performances of the robot are: footprint ~1cm2; throughput ~10 operations/s and translation accuracy < 1µm (for translation range > 200µm). Such a robot will be the most compact, the most accurate, and the fastest micro/nano-manipulator in the world.

Related publications and patents:
International Journals:
W. Haouas, R. Dahmouche, N. Le Fort-Piat, and G. J. Laurent, “A New Seven Degrees-of-Freedom Parallel Robot With a Foldable Platform,” J. Mech. Robot., vol. 10, no. 4, p. 045001, 2018.
W. Haouas, R. Dahmouche, J. Agnus, N. Le Fort-Piat, and G. J. Laurent, “New integrated silicon-PDMS process for compliant micro-mechanisms,” J. Micromechanics Microengineering, vol. 27, no. 12, p. 127001, Dec. 2017.
International conferences:
W. Haouas, R. Dahmouche, and G. J. Laurent, “Analysis of an Integrated 4-DoF Parallel Wrist for Dexterous Gripping,” in 2018 IEEE 14th International Conference on Automation Science and Engineering (CASE), 2018, vol. 2018-Augus, pp. 1448–1453.
W. Haouas, R. Dahmouche, N. Le Fort-Piat, and G. J. Laurent, “4-DoF spherical parallel wrist with embedded grasping capability for minimally invasive surgery,” in IEEE International Conference on Intelligent Robots and Systems, 2016, pp. 2363–2368.
Related patents:
R. Dahmouche and W. Haouas, “Robotic Structure with Six Degrees of Freedom Allowing Gripping,” WO2018065702, 2016.
G. Laurent, R. Dahmouche, W. Haouas, and N. Piat, “Parallel Robotic Wrist with Four Degrees of Freedom,” WO 2018/065734, 2018.

The goal of MiniSoRo is to develop a new generation of dexterous, compact and precise robots as well as methods to design, model and control them to perform fine and dexterous manipulation at small scales. These robots represent the main bricks of the future automated assembly system of nanodevices supporting the current nanotechnology revolution.

The main scientific hypotheses on which MiniSoRo is based are the followings: i) ground-breaking technologies based on micro/nanodevices integrating heterogeneous materials (nanowires, nanotubes, photonic crystals, etc.) that have impact on several domains (medical, information, security, etc.) are not massively produced because of the lack of appropriate manipulation and assembly systems; ii) contact manipulation is suitable for manipulation especially when heterogeneous materials have to be assembled and; iii) current manipulation systems do not have the required functionalities/performances to achieve the required manipulation and assembly tasks and/or ; iv) are not compatible with the operating environment (Scanning Electron Microscopes, MRI, etc.).

The main scientific barriers that will be lifted by MiniSoRo are related to the current robots structures, models and technologies that are not able to combine dexterity, precision and compactness into the same robotic system to be able to properly operate inside confined spaces. The proposed approach in MiniSoRo is to integrate flexible materials as links/joints instead of classical mechanical joints into micro-parallel mechanisms in order to: i) eliminate the mechanical defects such as backlashes; ii) develop highly compact mechanisms and; iii) cover a large workspace in translation and rotation.

Indeed, manipulating miniature objects with robots of comparable dimensions will improve the resolution of the positioning and integrate a large number of robots per unit area. In addition, the low masses and inertia of this type of robot can achieve significant yield compared to conventional bulky robots.

The expected scientific results from MiniSoRo are the development of original methods for modeling, designing, and controlling miniaturized parallel robots composed of rigid and flexible elements with large deformations, as well as the development of methods to control the position, the force and the compliance of these robots. Self-calibration methods of soft robots with redundant measurement will also be investigated. The technological contributions are: i) the development of technologies and processes for the fabrication and integration of soft/flexible elements into submillimetric and micrometric structures and; ii) the integration of sensors to measure the positions and the torques at the robot base and actuators into the robotic structures. The developed robot will be characterized and used to assemble a junctionless nanowire transistor, which is the main technology used for nanowire based sensors.

MiniSoRo will thus significantly contribute to the development of new nanotechnologies that find applications in health, energy, communication, security and defence and others.