IROS 2020 论文列表

In this study, we developed a selective driving joint forceps (SDJF) for laparoscopic surgery. The SDJF has a mechanism that the driving joints can be selected arbitrarily, therefore each joint doesn't require an individual actuator for operating. The developed SDJF has six joints that can be operated using only four actuators. Each joint has 2-degrees-of-freedom (DOF) of flexion. Therefore, the SDJF has the same working area as the forceps having six driving joints (each joints can bend ±30° around the X and Y axes). The mechanism of the SDJF is realized by fixing each joint with a collar made of shape memory polymer. The proposed mechanism not only reduces the number of actuators required for joint operation, but also has the rigidity of the forceps, which is important in surgery. In addition, a driving section of the forceps is driven by pneumatic cylinders, therefore, the forceps joint has high-back-drivability, lightweight and high-output. We measured the heating and cooling time required to change the driving joint, dynamic response and rigidity of the prototype SDJF.

Measuring the forces that humans exert with their fingers could have many potential applications, such as skill transfer from human experts to robots or monitoring humans. In this paper we introduce the "Exo-Glove" system, which can measure the joint angles and forces acting on the human finger without covering the skin that is in contact with the manipulated object. In particular, 3-axis sensors measure the deformation of the human skin on the sides of the finger to indirectly measure the 3-axis forces acting on the finger. To provide a frame of reference for the sensors, and to measure the joint angles of the human finger, an exoskeleton with remote center of motion (RCM) joints is used. Experiments showed that with the exoskeleton the quality of the force measurements can be improved.

During the last two decades, minimally invasive surgery (MIS) has become popular because it offers advantages such as less pain, faster recovery, improved cosmesis, and reduced complications. Single-port laparoscopic surgery is a form of MIS where surgeons operate exclusively through a single entry. However, the view from the rigid endoscope is often obscured by the instruments which pass through the same single entry. To remove the need for a secondary viewing port and the blind spots during operation, we propose a deployable wrist mechanism for minimally invasive laparoscopic surgery. It utilizes an S-shape nitinol tube with a curvature of 15 mm and 1.83 mm in diameter. When retracted, the s-shaped wrist is straightened into the main shaft of the laparoscopic tool. As the wrist translates outward, the S-shaped nitinol wrist emerges from an opening on the tool shaft and bends to point at the tooltip. The wrist has two degrees of freedom: translational displacement for controlling the bending and rotational movement of the wrist. The bending mechanism was analyzed by finite element method simulation and validated by experiments. For future work, we will try to widen the scope of its applications including laser ablation tools, triangularization, and other microsurgical procedures.

Landing is an essential part of multicopter task operations. A multicopter has relatively stringent requirements for landing, particularly for achieving flatness. Currently, landing on rough terrain with normal skids is difficult. Therefore, research is being conducted to obtain skids capable of landing on rough terrain. In this paper, a passive skid for multicopter landing on rough terrain is proposed. The proposed device is based on an existing previous study of the multicopter carried with a electric robo-arm only for object manipulation. This innovative idea stems from the aim of giving the multicopter carried with a electric robo-arm the ability to land on various occasions and then the passive skid is designed. By using a slope to simulate a rough terrain, the range of available landing in which a multicopter can maintain its pose and the frictional torque of the passive joint are analyzed. Further, experiments are conducted to demonstrate that landing can be achieved using the skid proposed in our study.

Future robots are expected to share their workspace with humans. Controlling and limiting the forces that such robots exert on their environment is crucial. While force control can be achieved actively with the help of force sensing, passive mechanisms have no time delay in their response to external forces, and would therefore be preferable. Series clutch actuators can be used to achieve high levels of safety and backdrivability. This work presents the first implementation of a linear series clutch actuator. It can exert forces of more than 110N while weighing less than 2kg. Force controllability and safety are demonstrated. Static balancing, which is important for the application in a vertical joint, is also implemented. The power consumption is evaluated, and for a payload of 3kg and with the maximum speed of 94mm/s, the power consumed by the actuator is 11W. Overall, a practical implementation of a linear series clutch actuator is reported, which can be used for future collaborative robots.

As a novel therapy for peritoneal dissemination, it is desired to actualize an endoscopic photothermal therapy, which is minimally invasive and is highly therapeutically effective. However, since the endoscopic tumor temperature control has not been actualized, conventional therapies could damage healthy tissues by overhearing. In this paper, we develop a thermal endoscope system that controls the tumor temperature so that the heated tumor gets necrotic. In fact, our thermal endoscope contains a thermal image sensor, a visible light endoscope and a laser fiber. Concerning the thermal image sensor, the conventional thermal endoscope has the problem that the diameter is too large, because the conventional endoscope loads a large thermal image sensor with high-resolution. Therefore, this paper uses a small thermal image sensor with low resolution, because the diameter of the thermal endoscope needs to be smaller than 15mm in order to be inserted into the trocar. However, this thermal image sensor is contaminated by much noise. Thus, we develop a tumor temperature control system using a feedback control and tumor temperature estimation based on Gaussian function, so that the noisy, small thermal image sensor can be used. As experimental results of the proposed endoscopic photothermal therapy for the hepatophyma carcinoma model of rats, it turns out that the tumor temperature by which the heated tumor gets necrotic can be kept stable. It can be said that our endoscopic photothermal therapy achieves a certain degree of therapy effect.

This work investigates an efficient trajectory generation for chasing a dynamic target, which incorporates the detectability objective. The proposed method actively guides the motion of a cinematographer drone so that the color of a target is well-distinguished against the colors of the background in the view of the drone. For the objective, we define a measure of color detectability given a chasing path. After computing a discrete path optimized for the metric, we generate a dynamically feasible trajectory. The whole pipeline can be updated on-the- fly to respond to the motion of the target. For the efficient discrete path generation, we construct a directed acyclic graph (DAG) for which a topological sorting can be determined analytically without the depth-first search. The smooth path is obtained in quadratic programming (QP) framework. We validate the enhanced performance of state-of-the-art object detection and tracking algorithms when the camera drone executes the trajectory obtained from the proposed method.

Awareness of the environment is essential for mobile robots. Perception for legged robots requires high levels of reliability and accuracy in order to walk stably in the types of complex, cluttered environments we are interested in. In this paper, we present a usable environmental perception algorithm designed to detect steppable areas and obstacles for the autonomous generation of desired footholds for legged robots. To produce an efficient representation of the environment, the proposed perception algorithm is desired to cluster point cloud data to planar regions composed of convex polygons. We describe in this paper the end-to-end pipeline from data collection to generation of the regions, where we first compose an octree in order to create a more efficient data representation. We then group the leaves in the tree using a nearest neighbor search into a planar region, which is composed of the concave hull of points that is decomposed into convex polygons. We present a variety of environments, and illustrate the usability of this approach by the Atlas humanoid robots walking over rough terrain. We also discuss various challenges we faced and insights we gained in the development of this approach.

Designing robots capable of generating interpretable behavior is essential for effective human-robot collaboration. This requires robots to be able to generate behavior that aligns with human expectations but exhibiting such behavior in arbitrary environments could be quite expensive for robots, and in some cases, the robot may not even be able to exhibit expected behavior. However, in structured environments (like warehouses, restaurants, etc.), it may be possible to design the environment so as to boost the interpretability of a robot's behavior or to shape the human's expectations of the robot's behavior. In this paper, we investigate the opportunities and limitations of environment design as a tool to promote a particular type of interpretable behavior - known in the literature as explicable behavior. We formulate a novel environment design framework that considers design over multiple tasks and over a time horizon. In addition, we explore the longitudinal effect of explicable behavior and the trade-off that arises between the cost of design and the cost of generating explicable behavior over an extended time horizon.

Many manufacturing industries have a high demand for the construction of collaborative operation systems using industrial robots. Although there is a preexisting set of safety verification data in ISO/TS 15066 for collaborative operations, there is no established testing method for safety validation. To establish a testing method, it is effective to use a dummy that has mechanical properties similar to those of a human. However, there is no parametric study that exists for designing a dummy that represents the static and dynamic mechanical properties and the nonlinearity of the static mechanical properties. In this study, static and dynamic experiments were conducted to obtain the mechanical stiffness of human subjects and the contact force transitions during the dynamic contact between a robot system and a human. Subsequently, the same experiment was conducted using the proposed dummy. The biofidelity of the dummy was examined by comparing the parameters of a viscoelastic model. This study contributes to increasing the safety of collaborative operations by developing a dummy that can be used for risk assessments in collaborative operations.

This paper investigates the design of a three-degree-of-freedom rotational inertia generator using the gyroscopic effect to provide ungrounded torque feedback. It uses a rotating mass in order to influence the torques needed to move the device, creating a perceived inertia. The dynamic model and the control law of the device are derived, along with those of a comparable concept using three flywheels instead of a gyroscope. Both models are then validated through simulations. Further simulations are conducted to establish motor torque and velocity requirements, and the gyroscopic concept is identified as having the less demanding requirements. The mechatronic design of a prototype of an inertia generator is presented, along with modifications to the dynamic model. Preliminary experimental validations are conducted. As the prototype faces instability issues when using the flywheels at high velocities, they are conducted using 0 RPM initial velocities. The results confirm that it is possible to both reduce and increase the rendered inertia even with current limitations. Finally, improvements for a second version of the prototype are discussed.

This paper presents an innovative robotic mechanism for generating peristaltic motion for robotic locomotion systems. The designed underactuated peristaltic robot utilizes a minimum amount of electromechanical hardware. Such a minimal electromechanical design not only reduces the number of potential failure modes but also provides the robot design with great potential for scaling to larger and smaller applications. We performed several speed and force generation tests atop a variety of granular media. Our experiments show the effective design of robot mechanism where the robot can travel with a small input power (1.14W) at 6.0 mm/sec with 2.45 N force atop sand.

This paper presents a smart continuum actuator based on a promising class of materials: ElectroActive polymer (EAP). Indeed these polymers undergo dimensional change in response to an applied electrical field and could be integrated directly in an endoscopic robot structure. We focuses on one of such materials, an electrostrictive polymer, for its valuable strain performances. An analytical model leading to the development of an experimental analysis of such a material in an attempts to overcome the technical gap of their integration into a multilayer composite sheet to perform robotic actuation is the subject of this article.

Most existing mechanical gravity compensators have been developed for revolute joints that are found in majority of articulated robot arms. However, robots such as patient transport robots use prismatic joints, which need to handle a heavy payload. In this study, a high-capacity linear gravity compensator (LGC), which comprises pure mechanical components, such as coil springs, a rack-pinion gear, a cam, and a wire, is proposed to compensate for the payload applied to a prismatic joint. The LGC is designed to generate a constant compensation force regardless of the payload position. The device can be manufactured at a low cost and has a significantly long lifespan because it uses coil springs to serve as an elastic body. Experiments demonstrate that the robot with the LGC can handle a load of 100 kg more than the robot using the same motors without it.

This paper presents the design of a new soft pneumatic actuator whose direction and magnitude of bending may be precisely controlled via activation of different shape memory alloy (SMA) springs within the actuator, in conjunction with pneumatic actuation. This design is inspired by examples seen in nature such as the human tongue, where the combination of hydrostatic pressure and contraction of intrinsic muscle groups enables precise maneuverability and morphing capabilities. Here, SMA springs are embedded in the walls of the actuator, serving as intrinsic muscles that may be selectively activated to constrain the device. The pneumatic SMA (PneuSMA) actuator demonstrates remarkable spatial controllability evidenced by testing under different pressures and SMA activation combinations. A baseline finite element model is also developed to predict the actuator deformation under different pressure and activation conditions.

High-level control is generally preferred for the control of complex robot platforms and by users inexperienced with robot teleoperation. However, high-level teleoperation interfaces can be less effective if the robot autonomy is not reliable. To address this problem, it is important to understand how the users' preference of teleoperation interface may vary with the reliability of the robot autonomy, and understand what design features ameliorate the frustration and effort caused by unreliable autonomy.This paper proposes a graphical user interface for high-level robot control. The framework of the interface enables teleoperators to control a robot at the action level, and incorporates a simple but effective design that enables teleoperators to recover from task failure in a number of ways. We conducted a user study (N = 25) to compare the performance and user experience when using the proposed high-level interface to a low-level interface (i.e., gamepad) for robot low-level control, on a representative manipulation task. We also investigated if the high-level teleoperation interface remains effective if the reliability of robot autonomy decreases. Our results show that a high-level interface able to handle the most frequent errors is resilient to the effects of unreliable robot autonomy. Although the total task completion time increased as the robot autonomy becomes unreliable, the users' perception of workload and task performance are not affected. Through the user study, we also reveal the desirable interface features.

Soft actuators have been widely studied in recent years because of their ability to adapt to diverse environments and safely interact with humans. Their softness broadens their potential range of medical applications since they can provide inherent safety. Among the various motions a soft robot can perform, "torsion" can maximize the efficiency of motion in confined spaces like the human abdominal cavity. This paper presents a fully soft actuator with a double-helix tendon routing path for large-angle torsional motions. The double-helix tendon routing enables the actuator to generate large twisting deformations, while also avoiding buckling generally associated with the torque imbalance in small diameter soft cylinder structures. A sequential casting method was developed for cylindrical structures with internal double-helix pathing. A parametric study of the actuator’s twisting angle and the axial contraction with respect to different design parameters was conducted, including the wire tension and path pitch. From the results, when the tendon was pulled with 40 N after the pitch was decreased, the axial contraction of the soft actuator was reduced by half and the torsional angle was doubled up to 600° without buckling.

In this paper, we updated an inspection robot with passive adaptation ability, which is used to detect small size water supply pipeline. By geometric calculation and kinematic verification, static model of the robot is checked for flexible movement in the pipeline. Besides, inertial measurement unit is leveraged to simultaneously detect the attitude of robot, and different algorithm is tested to compensate the camera image rotation, stabilizing the image output.