ICRA 2024 Papers

The aging population and diminishing working population in agriculture motivate the development of autonomous harvesting robots. Although autonomous harvesting is expanding rapidly, the commercial application of sweet pepper harvesting robots still faces challenges. This paper presents the development of a sweet pepper harvesting robot and reports its experimental verification, which mainly includes end-effector design, visual perception, and grasping pose control. The end-effector adopts electrical control, mainly composed of a servo-electric two-finger parallel clamping module, a swing-cutting module, and a fruit recovery device. Equipped with a tactile sensor array, it can accurately sense the sweet pepper peduncle position and the end-effector state (harvesting failure) to complete the precise cutting. An end-effector grasping pose control algorithm of the manipulator is proposed, which can control the end-effector to grasp along the direction of the fruit peduncle and perpendicular to the tangent direction of the picking point by estimating the pose of the sweet pepper peduncle. Finally, the robot and proposed method were verified in a plant factory. The experimental findings demonstrate that the developed harvesting robot can complete robust detection of fruit peduncles and non-destructive picking of sweet pepper, with an average picking time of about 15 seconds.

In recent years, micromanipulation technology has achieved extensive applications in industry and life science. Improving the precision and bandwidth of the micromanipulator and simultaneously reducing size, weight, and cost pose significant challenges to the existing micromanipulator design and fabrication methods. Here, we propose a 3-RRS micromanipulator with an origami-inspired spherical joint based on the PC-MEMS process, aiming for miniaturization and cost-effectiveness. The spherical joint allows rotations of 140° around the x-axis approximately, 140° around the y-axis approximately, and 20° around the z-axis approximately. The micromanipulator has weights of 0.8 g, dimensions of 16 mm × 16 mm × 22 mm, and workspace of 0.7 mm3. The end platform of the micromanipulator can be equipped with various effectors to accomplish different kinds of tasks. Experimental results validated its high precision and bandwidth, exhibiting its potential to perform intricate micromanipulation tasks.

Series Elastic Actuator-based exoskeleton can offer precise torque control and transparency when interacting with human wearers. Accurate control of SEA-produced torques ensures the wearer’s voluntary motion and supports the implementation of multiple assistive paradigms. In this paper, a novel variable transmission series elastic actuator (VTSEA) is developed to meet torque-speed requirements in different exoskeleton-assisted locomotion modes, such as running, walking, sit-to-stand, and stand-to-sit. The VTSEA features a SEA-coupled variable transmission ratio adjusting mechanism and works between three discrete levels of transmission ratio depending on the user’s initiative. The proposed prototype can also improve transparency in human-robot interaction. Also, an accurate torque controller with inertial compensation is developed for the VTSEA via the singular perturbation theory, and its stability is proved. The feasibility of the proposed VTSEA prototype and the precise output torque performance of VTSEA are verified by experiments.

Autonomous systems, such as self-driving cars and drones, have made significant strides in recent years by leveraging visual inputs and machine learning for decision-making and control. Despite their impressive performance, these vision-based controllers can make erroneous predictions when faced with novel or out-of-distribution inputs. Such errors can cascade to catastrophic system failures and compromise system safety. In this work, we introduce a run-time anomaly monitor to detect and mitigate such closed-loop, system-level failures. Specifically, we leverage a reachability-based framework to stress-test the vision-based controller offline and mine its system-level failures. This data is then used to train a classifier that is leveraged online to flag inputs that might cause system breakdowns. The anomaly detector highlights issues that transcend individual modules and pertain to the safety of the overall system. We also design a fallback controller that robustly handles these detected anomalies to preserve system safety. We validate the proposed approach on an autonomous aircraft taxiing system that uses a vision-based controller for taxiing. Our results show the efficacy of the proposed approach in identifying and handling system-level anomalies, outperforming methods such as prediction error-based detection, and ensembling, thereby enhancing the overall safety and robustness of autonomous systems. Website: phoenixrider12.github.io/FailureMitigation

In the healthcare industry, nursing robots have made great contributions, assisting in the delivery of food and medicine as well as the movement and transfer of patients. However, the traditional continuum manipulator often has the problems of limited workspace and weak carrying capacity. Compared with traditional manipulator, the continuum manipulator has the advantages of a small moment of inertia and high dexterity. This paper proposes a original cable-driven parallel continuum manipulator with a spherical parallel mechanism as the continuous segments. Due to the spherical parallel mechanisms’ characteristics, the proposed cable-driven spherical parallel continuum manipulator offers many inherent advantages for nursing robots. The prototype is tested and analyzed, and the kinematics and statics are verified. The results show that the cable-driven spherical parallel continuum manipulator for nursing robots has low requirements for workspace, suitable for complex spaces and can have a large carrying capacity.

For researchers or administrators of relevant institutions who need to collect hydrological data of a certain water area, using autonomous sailboats to tow floating detection equipment is an energy-saving and convenient scheme for deploying detectors. However, due to the limited pulling force provided by a single autonomous sailboat, this scheme is not suitable for floating equipment with large masses. This paper proposes a new approach for multiple autonomous sailboats to tow floating objects. A system of linear arrangement and connection of two autonomous sailboats is considered an appropriate solution for towing heavy floating objects because of its ability to provide greater pulling force. The main part of the article introduces a new design of multi sailboat towing system that can tow floating objects to sail with or against wind. Repetitive experiments have been conducted at the test site equipped with a motion capture system to find the best strategy to control the sails and rudder, in order to increase the towing system’s pulling force and tacking success rate. Three connection modes are proposed, compared, and tested. The best one is applied to the sailboat’s towing system and improves its performance.

Many individuals experience knee dysfunctions attributed to the natural aging process and degenerative conditions. To aid individuals in regaining knee functionality, supportive exoskeletons were designed to be affixed to both the shin and thigh. However, a common issue encountered in knee exoskeletons involves the misalignment of joints between the exoskeleton and the user, resulting in discomfort and potential injuries. To reduce misalignment with the knee joint, it is essential for the thigh and shin harnesses of the exoskeleton to replicate the natural trajectories of the knee. However, achieving this is a complex task due to the shifting center of rotation of the knee in both the Sagittal and Coronal planes. Previous knee exoskeletons primarily focus on aligning the joint in the Sagittal plane, neglecting alignment in the other dimension due to inherent design constraints. For the first time, this study introduces a knee-joint exoskeleton capable of conforming to the natural movement of the knee in both the Sagittal and Coronal planes, with the aim of minimizing joint misalignment without the use of inherently soft materials. A spherical scissor linkage mechanism (SSLM) was utilized in conjunction with a customized guide rail to adjust the center of rotation of the SSLM. This configuration facilitates knee flexion/extension while accommodating the knee joint’s center of rotation in both the Sagittal and Coronal planes. The experimental outcomes demonstrated a substantial reduction in misalignment with the knee when compared to a commercial knee-support brace with a one-degree-of-freedom revolute joint.

Traditionally, powered exoskeletons have predominantly featured a back-enveloping design due to its simplicity in both implementation and user donning. However, this design results in a backward shift of the center of mass (CoM) in the sagittal plane. This paper identifies the limitations of existing design approaches and determines the optimal anterior-posterior (A/P) CoM position considering factors like actuating power, balance in the neutral posture, and user’s hand workspace. Our optimization analysis recommends placing the CoM in front of the user. We address historical constraints on front-enveloping designs and propose solutions. Furthermore, we validate the usability of our designed exoskeleton through testing with a complete paraplegic user.

We propose, examine prototypes of, and collect user input on morphing robotic surfaces, "robot-room" elements that, individually or in combination, change the functionality of the rooms we live in, directly controlled by the room’s occupants engaging with it. Robot-rooms represent an advance in human-robot interaction whereby human interaction is within a machine that physically envelops us. We discuss the motivation for such robot-rooms, present initial work aimed at their physical realization, and report on a user study of 80 participants to learn what people might want of and expect from robot rooms, the results of which will inform both the iterative design of the robot room and the thinking of our community as it grapples with how we want to live with (and "in") robots.

In this paper, we explain the Morphable StateNet as the StateNet with pseudo-generalized behaviors for robots with various degree-of-freedom arrangements and link lengths. Pseudo-generalization is performed by analytically calculating joint angles that satisfy the desired support conditions, focusing on link lengths and antigravity joints that contribute to motion, with constraints placed on the contact conditions between the environment and the robot body. We apply Morphable StateNet to the standing-up motion of humanoids with variable body structures and conduct evaluation experiments. We have demonstrated the usefulness of the proposed method in environments with low friction coefficients with the environment by conducting evaluations using both a simulator and an actual humanoid.

This paper presents a novel approach to designing, a low-cost gripper that is highly repeatable and functionally integrated. The gripper is optimized to compensate for gripping errors with particular consideration to potential challenges of articulated robots. The primary design goal is to achieve maximum repeatability during the gripping and releasing stages of a pick-and-place process for a chip-like silicon die. The design is centered around a custom printed circuit board integrates functionality for vision-based error compensation, vacuum level monitoring, part contact detection, and detection of abnormal vibrations. We detail our design requirements and specific design choices for the mechanical and electronic design and provide qualitative and quantitative experimental validation of the achieved repeatability and the integrated functions.

Social robots for children have focused mainly on conventional education domains such as teaching language, science, and math, while applications focusing on the enhancement of cultural competency are quite scarce. In this paper, we present a prototype of a robot-mediation framework for cross-cultural communication. This framework paves the way for a social robot to act as a mediator between groups of schoolchildren from different countries. First, we conducted a participatory design activity by an interdisciplinary team, resulting in the extraction of the design, robot’s roles, and technical requirements. Based on these requirements, we built the robot-mediation system prototype. We conducted a pilot study using the system with groups of high school children in Japan and Australia and our results show the potential of the system to drive children’s interest in communicating, sharing, and discussing cultural themes with their remote peers through the social robot.

Soft robotic gloves can not only provide timely, effective, safe and cheap rehabilitation training for patients with impaired movement function of hand, but also assist in completing daily grasping activities. However, most soft robotic gloves are completely composed of flexible structures. Although they have high flexibility and safety, there are problems such as poor fit and low output force. In order to solve these problems, this paper refers to the structure of the human hand and designs an articulated rigid-soft hybrid robotic glove, which combines the advantages of rigid robotic gloves and soft robotic gloves, and has high flexibility, high output force and good fit. In addition, soft robotic gloves generally lack the ability to sense the force between the human hand and the glove. Therefore, this paper designed an array flexible force sensor, and studied the structure, signal acquisition and preparation process of the sensor. Finally, a complete test platform was built to test the performance of the rigid-soft hybrid robotic glove with force sensing function. The test results show that the robotic glove has good fit and high output force, can effectively assist training and assist grasping, and can perceive the contact force.

The solar array wing deployment of orbiting satellites cannot be performed due to power failure of the connector caused by uncertain loads such as high temperature or vibration in the launching process of the spacecraft. There is currently a lack of suitable unlocking solutions for solar wing re-unfolding. This paper proposes a solution in which an extensible continuum robot (ECR) carrying the unlocking device enters the gap between the satellite and the solar wing, re-unlocking the solar wing. This solution effectively leverages the advantages of ECR collision buffering and adaptable maneuverability within confined space. In response to the proposed solution, the designed ECR with two segments helical spring structure features scalability, hollowness, lightweight, and a big length-diameter ratio. To perform the critical unlocking task, an end effector with the function of loosening and unplugging the aerospace connector for communication is designed based on the drive device away from itself to reduce the inertia of the manipulator. The information from the cameras and force sensors is used to estimate the extent of task execution. We establish an experimental setup to simulate the process of unlocking. The results validate that the ECR successfully accesses the gap (65mm) and accomplishes the unlocking task. The ECR has great application potential for on-orbit service.

The manipulation of instruments under a microscope suffers from physiological tremor and human errors, which are inevitable in long microsurgery interventions. Robotic systems developed in recent years for microsurgery are expensive and not flexible, as they cannot use standard instruments, and need the surgeon to modify their operative skills and strategies. In this paper, we introduce a modular robotic system for microsurgery enabling the surgeon to operate using conventional instruments. Our system was implemented using a commercial Kinova robot and a dedicated modular end-effector that uses standard microsurgery instruments. An initial teleoperation validation was carried out by eleven participants, who could successfully control the microsurgery tools to perform basic surgical movements. Furthermore, participants performed a simple anastomosis task with the robot and compared it to manual control. The results showed that robotic control is superior to manual control in simple surgical tasks and the converse in complex tasks. Participants preferred the proposed robotic system due to its user-friendliness and effort reduction.

Traditional rigid endoscopes have challenges in flexibly treating tumors located deep in the brain, and low operability and fixed viewing angles limit its development. This study introduces a novel dual-segment flexible robotic endoscope MicroNeuro, designed to perform biopsies with dexterous surgical manipulation deep in the brain. Taking into account the uncertainty of the control model, an image-based visual servoing with online robot Jacobian estimation has been implemented to enhance motion accuracy. Furthermore, the application of model predictive control with constraints significantly bolsters the flexible robot’s ability to adaptively track mobile objects and resist external interference. Experimental results underscore that the proposed control system enhances motion stability and precision. Phantom testing substantiates its considerable potential for deployment in neurosurgery.

This paper presents a free-swimming, tetherless, cable-driven modular soft robotic fish. The body comprises a series of 3D-printed wave spring structures that create a flexible biologically inspired shape that is capable of an anguilliform swimming gait. A three-module soft robotic fish was designed, fabricated, and evaluated. The motion of the robot was characterized and different combinations of actuation amplitude, frequency, and phase shift were determined experimentally to determine the optimal parameters that maximized speed and minimized the cost of transport (COT). The maximum speed recorded was 0.20 BL/s (body lengths per second) with a COT of 15.82. These results were compared against other robotic and biological fish. We operated the robot, untethered, in a variety of environments to test how it was able to function outside of laboratory settings.

Soft growing robots with unique navigation (tip extension by eversion) hold great promise in rescue, medical, and industrial applications. Equipping them with grasping capability would enhance their usefulness in constrained environments for various applications. However, in traditional designs, the tip’s eversion naturally conflicts with grasping, and the addition of grippers at the tip would limit navigation inevitably in constrained environments. To realize grasping in such scenes without extra devices, we propose a nested bi-cavity-based growing soft robot (BIBOT). The new design consists of two coaxially nested cavities, where the inner and outer cavities extend synchronously by inversion and eversion of the film rolls. Such a bi-cavity design enables the BIBOT to navigate and grasp without relative movements between the body and environment, and avoids contact between the object and its surroundings as well. Further, a kinematics model is established and verified to precisely control its lengthening and steering by a feed mechanism. Finally, its capability in a constrained environment is demonstrated by navigating and grasping an object in a curved pipe with a variable internal diameter.

Variable stiffness actuator (VSA) can imitate natural muscles in their compliance capbility, which can provide flexible adaptability for robots, improving the safety of robots interacting with the environment or human. This paper presents a new compact serial variable stiffness actuator ((SVSA-III)) with linear stiffness profile based on symmetrical variable lever arm mechanism. The stiffness motor is used to regulate the position of the pivot located on the Archimedean Spiral Relocation Mechanism (ASRM), so that the stiffness of the actuator can be adjusted (softening or hardening). By designing the lever length, the range of stiffness adjustment can change from 0.3Nm/degree to therotical infinity. Moreover, the continuous linear stiffness profile of the actuator can be customized by solving the transcendental equation of the relationship between the actuator stiffness and the rotation angle of the stiffness motor. SVSA-III has the advantages of compact structure, wide-range stiffness regulation, reduced control difficulty, and linear stiffness profile. Two experiments of step response and stiffness tracking have proved the high accuracy and fast response for both theoretical stiffness and position adjustment.