In order to expand the operational range and payload capacity of robots, wire-driven robots that leverage the external environment have been proposed. It can exert forces and operate in spaces far beyond those dictated by its own structural limits. However, for practical use, robots must autonomously attach multiple wires to the environment based on environmental recognition―an operation so difficult that many wire-driven robots remain restricted to specialized, pre-designed environments. Here, in this study, we propose a robot that autonomously connects multiple wires to the environment by employing a multi-small flying anchor system, as well as an RGB-D camera-based control and environmental recognition method. Each flying anchor is a drone with an anchoring mechanism at the wire tip, allowing the robot to attach wires by flying into position. Using the robot’s RGB-D camera to identify suitable attachment points and a flying anchor position, the system can connect wires in environments that are not specially prepared, and can also attach multiple wires simultaneously. Through this approach, a wire-driven robot can autonomously attach its wires to the environment, thereby realizing the benefits of wire-driven operation at any location.

Tendon-driven mechanisms are useful from the perspectives of variable stiffness, redundant actuation, and lightweight design, and they are widely used, particularly in hands, wrists, and waists of robots. The design of these wire arrangements has traditionally been done empirically, but it becomes extremely challenging when dealing with complex structures. Various studies have attempted to optimize wire arrangement, but many of them have oversimplified the problem by imposing conditions such as restricting movements to a 2D plane, keeping the moment arm constant, or neglecting wire crossings. Therefore, this study proposes a three-dimensional wire arrangement optimization that takes wire crossings into account. We explore wire arrangements through a multi-objective black-box optimization method that ensures wires do not cross while providing sufficient joint torque along a defined target trajectory. For a 3D link structure, we optimize the wire arrangement under various conditions, demonstrate its effectiveness, and discuss the obtained design solutions.

A wire-driven parallel robot is a type of robotic system where multiple wires are used to control the movement of a end-effector. The wires are attached to the end-effector and anchored to fixed points on external structures. This configuration allows for the separation of actuators and end-effectors, enabling lightweight and simplified movable parts in the robot. However, its range of motion remains confined within the space formed by the wires, limiting the wire-driven capability to only within the pre-designed operational range. Here, in this study, we develop a wire-driven robot, CubiX, capable of connecting to and utilizing the environment. CubiX connects itself to the environment using up to 8 wires and drives itself by winding these wires. By integrating actuators for winding the wires into CubiX, a portable wire-driven parallel robot is realized without limitations on its workspace. Consequently, the robot can form parallel wire-driven structures by connecting wires to the environment at any operational location.

Traversability estimation is essential for safe path planning in robotics and autonomous driving. In this study, we propose an accurate and dense traversability estimation system for extreme environments such as disaster areas. Traversability estimations often occur undefined regions due to the shielding and sparsity of sensor data. These regions may lead to the selecting of dangerous paths. The proposed system uses point cloud accumulation and the Bayesian generalized kernel (BGK) elevation estimation to create a dense Digital elevation map (DEM) with no undefined regions from point clouds obtained from light detection and ranging (LiDAR). Subsequently, traversability is estimated from road surface roughness, slope and vehicle performance using fuzzy logic in our system. In our experiments, our system is installed in an experimental vehicle, and the experiments conducted on rocky terrain, slopes, and craters to verify its effectivity in extreme environments. Results show that our system can create a dense DEM with few undefined regions and estimate valid traversability for all obstacles.

Elderly drivers often tend to disobey stop signs, and the number of vehicle accidents associated with this is increasing. The problem we address in this work is that of failure (or inability) of elderly drivers to identify potential conflicts with other road users at stop-sign intersections. The purpose of the study is to investigate the influence of deceleration control with brake hold on the driving habits of elderly drivers in potentially hazardous situations. This study proposes a driver assistance system with three functionalities: 1) information provision to warn drivers that they are approaching a stop-sign intersection; 2) deceleration control to stop the vehicle; and 3) brake hold to ensure that the vehicle has stopped completely. The timeline for a stop-sign intersection scenario is divided into pre- and post-vehicle-stop phases. The effectiveness of the proposed approach in the context of braking-assistance intervention was evaluated by conducting a public-road driving experiment involving 34 elderly drivers. It was observed that the participants could be guided to exhibit rule-following driver behavior voluntarily. The proposed system increased safety for elderly drivers, not only by avoiding stop-sign violations, but also by increasing the available time for a driver to search for hidden hazards in blind spots. We conclude that the braking-assistance intervention system is effective in helping drivers avoid failure or inability to search for potential conflict owing to stop-sign violations.