Accurate fabric alignment is a critical step that must be performed before sewing. This paper presents a novel automated fabric alignment system. The system estimates the poses of top and bottom fabric panels—lying flat and wrinkle-free in arbitrary positions—using a new Global Local Weighted Iterative Closest Point (GLW-ICP) method. The system then manipulates the top panel to achieve precise alignment at both edges and sewing lines. Unlike conventional approaches, GLW-ICP robustly aligns both global edges and local sewing lines by globally aligning fabric edge points and locally aligning sewing line points to their corresponding CAD model points, while removing unmatched points in occluded regions. Real-world experiments with various fabric shapes show that the system consistently achieves millimeter-level alignment accuracy under both occlusion and non-occlusion conditions, demonstrating its effectiveness and suitability for automated fabric alignment in practical scenarios. Note to Practitioners—Fabric panel alignment before sewing is a time-consuming and skill-dependent task in garment production. Misaligned edges or sewing lines can lead to defects, rework, and production delays. This work presents a novel robotic system that automates the alignment of wrinkle-free fabric panels, even when portions of the panel are occluded by the manipulator. The system uses a novel Global Local Weighted Iterative Closest Point (GLW-ICP) method, which separately aligns overall panel edges and local sewing lines to a digital CAD model while ignoring unreliable points from occluded regions. A roller-based end-effector then picks up, re-positions, and releases the top panel to achieve precise alignment with the bottom panel. This method achieves millimeter-level accuracy across various garment components under both unoccluded and partially occluded views. This reduces operator dependency, improves consistency, and shortens preparation time. The approach is readily applicable to a wide range of garment components and can be adapted to various production settings. These capabilities open opportunities for end-to-end automation in apparel manufacturing, from panel preparation to stitching, further enhancing productivity and quality control.

This paper proposes a fixture-free 2D sewing system using a dual-arm manipulator, i.e., the seam lines of the top and bottom fabric parts are the same. The proposed 2D sewing system sews two stacked fabric parts together along a desired seam line printed on the top fabric part without the use of a fixture. In the proposed system, the set of aligned and stacked fabric parts is held by the end-effectors of the dual-arm manipulator in coordination. The dual-arm manipulator controls the motion of the fabric parts on the flat sewing table stitch by stitch in coordination, while keeping the manipulated fabric parts flat using the internal force applied to the set of fabric parts. A novel vision-based seam line tracking control is proposed to control the motion of the set of fabric parts along the printed seam line on the top fabric part. The convergence of the tracking error is analyzed for sewing along both straight and curved seam lines and is shown to be specified by the control parameters. Sewing experiments show that the tracking error converges to zero as analyzed. The sewing experiments also show that the newly proposed trajectory generation method, which synchronizes the coordinated motion of the manipulators and the motion of the sewing needle, is essential for achieving accurate sewing.Note to Practitioners—Most semi-automatic sewing machines and pattern sewers on the market use fixtures to handle the stacked fabric parts. They require the user to customize the fixture depending on the shape, size, and material of the fabric parts to be sewn together. Users are required to redesign/reconfigure the fixture to sew different fabric parts. Our robotic sewing system is based on the concept of fixture-free sewing, i.e., the pose of the set of stacked fabric parts is controlled by the end-effectors without using the fixture. The internal force applied to the fabric parts by the end-effectors is used to keep the fabric parts flat, and the position of the fabric parts is controlled by the motions of the end-effectors in coordination with the proposed vision-based seam line tracking control. The proposed robotic sewing system provides practitioners with a new approach to fixture-free automatic sewing of fabric parts.

This paper proposes CNN-based visual servoing for simultaneous positioning and flattening of a soft fabric part placed on a table by a dual manipulator system. We propose a network for multimodal data processing of grayscale images captured by a camera and force/torque applied to force sensors. The training dataset is collected by moving the real manipulators, which enables the network to map the captured images and force/torque to the manipulator's motion in Cartesian space. We apply structured lighting to emphasize the features of the surface of the fabric part since the surface shape of the non-textured fabric part is difficult to recognize by a single grayscale image. Through experiments, we show that the fabric part with unseen wrinkles can be positioned and flattened by the proposed visual servoing scheme.

To reduce the risk of radiation leakages similar to the incident at the Fukushima Daiichi Nuclear Power Station, robots have been employed to remove fuel debris from reactors. To perform this process safely, it is important to monitor the interior of a reactor. A camera and neutron sensors are attached to the end of a robotic arm to monitor the interior of the reactor. The basic design requirement for the monitoring system is that the arm must be highly extendable and rigid. To achieve this, a novel compact long-reach manipulator with a joint structure built using a low-melting-point alloy (LMPA) is proposed. The LMPA enables switching between the free and locked states of the rotational joints of the manipulator. Herein, we first explain the design of the proposed joint structure and verify whether it has adequate mechanical strength. The required maximum torque to be sustained by the structure was calculated using the cantilever model, and the actual breaking torque was measured by the tensile test. Experimental results confirmed that the joint could withstand approximately 1.86 times the required torque. Finally, the effectiveness of induction heating, which is used to switch between the free and locked states of the joints, was evaluated experimentally. The LMPA arm was installed in the coil of the induction heating module, and the time required to melt LMPA was measured. The experimental results confirmed that the induction heating can change the state of the LMPA joint, and the time required for the melting is approximately 30.3 s. Therefore, the findings of this study show that the proposed system is capable of averting nuclear disasters through the prevention of radiation leakages at nuclear plants.

In this study, we propose a control strategy for a power-assisted cart based on its motion state. The power-assisted cart we developed has one motor, a differential gear, and brakes. This cart uses the motor and the differential gear for moving forward, and applying brakes to either wheel allows the cart to turn both left and right. Therefore, the power-assisted cart can support the user when going straight and turning despite having only one motor. In the past we developed a control method that allows to control the cart's speed around the operation point in order to keep its magnitude constant when the cart starts turning. This was necessary, as the differential gear causes a speed change during turning, because of its characteristics. However, the desired behavior when transitioning from straight motion to turning motion is different to the desired behavior when going from turning motion to straight motion. Therefore, in this paper we propose a control method to adjust the speed in the direction of motion based on the state of the cart. We validated the effectiveness of the proposed method through experiments and discussed the results.