Design and Experimental Study of Space Continuous Robots Applied to Space Non-Cooperative Target Capture

Space capture actuators face problems such as insufficient flexibility and electrical components that are vulnerable to extreme space environments. To address these problems, a centralized-driven flexible continuous robot based on a multiple scissor mechanism units is proposed in this study. The continuous robot body is composed of two scissor mechanism units coupled in series, and the base container’s three motors to drive the robot. The two scissor mechanism units ensure a wide range of flexible operations and the light weight of the robot. The centralized drive with three motors not only reduces the number of driving sources, but also ensures temperature control and protection of electrical components in the space environment. The kinematics and dynamics of the robot are analyzed, and the workspace and deformation performance of the robot are verified through experiments. Compared with other continuous robots, the proposed continuous robot retains the characteristics of continuous robots in a wide range of flexible operations. At the same time, the configuration is light and a small number of driving sources are used, which is suitable for extreme temperatures, vacuum, radiation, and strict resource-constrained environments in space.

Double-layer deployable mechanical network constructed of Threefold-symmetric Bricard linkages and Sarrus linkages

Threefold-symmetric (TFS) Bricard linkages are known for their excellent deployment performance properties. This paper proposes a novel networking method of TFS Bricard linkages and a double-layer mechanical network. First, the angle relationship for parts of the TFS Bricard linkage is analyzed. Then, the angle relationship of two TFS Bricard linkages connected by a scissor mechanism is studied. The result suggests that when the twist angles of the two TFS Bricard linkages are equal, their corresponding planes are parallel, and the link lengths have no effect on the parallel relationship. A novel networking method of the TFS Bricard linkage is recommended according to these results. This mechanical network is constructed of two different sized units and can be plane deployed and be folded with a smaller height. We also propose a hybrid linkage constructed of the TFS Bricard linkage and Sarrus linkage. Two kinds of double-layer mechanical networks are suggested by applying the hybrid linkage to a smaller unit in the mechanical network and using the hybrid linkage as the interlayer pillar. The new networking method and the double-layer mechanical network provide convenience for the TFS Bricard linkage's engineering application.

Design and Bending Analysis of a Metamorphic Parallel Twisted-Scissor Mechanism

The conventional scissor mechanism is used in modern engineering and robotic applications due to its metamorphic ability. The folding configuration provides the space-saving and unfolding provides longer linear expansion capability. However, a conventional scissor suffers unexpected and uncontrolled large bending deformation due to low bending stiffness while unfolding configuration, which may damage its structure. It also has a sudden bending singularity during unfolding, which may also damage the actuator. These limitations impose a significant constraint on real-life applications such as foldable robot arms, space robot arms, reconfigurable robots, etc. In this paper, we proposed a multi-strands parallel twisted-scissor mechanism (PTSM) to enhance its usability. The PTSM is inspired by a rope structure and designed by introducing a metamorphic segment (MS) using the S-shape linkage design approach to improve its bending stiffness without affecting conventional scissors' fundamentals. The PTSM has a unique feature of several automatic-link locking mechanisms to avoid singularity without using additional sensors, mechanism, or control. We experimentally checked the proposed design's functionality and its feasibility. We formulated a cantilever bending model for foldable PTSM with N metamorphic segments considering revolute joint clearance for bending estimation, experimentally verified, and analyzed the bending deformation in the X-Y and Y-Z planes. Also, it is compared with a conventional scissor. Finally, we found that PTSM is stronger than conventional scissor and can fold/unfold smoothly using a single linear actuator. PTSM can provide large linear displacement with small bending deformation without bending singularity.

Locomotion with Pedestrian Aware from Perception Sensor by Pavement Sweeping Reconfigurable Robot

Regular washing of public pavements is necessary to ensure that the public environment is sanitary for social activities. This is a challenge for autonomous cleaning robots, as they must adapt to the environment with varying pavement widths while avoiding pedestrians. A self-reconfigurable pavement sweeping robot, named Panthera, has the mechanisms to perform reconfiguration in width to enable smooth cleaning operations, and it changes its behavior based on environment dynamics of moving pedestrians and changing pavement widths. Reconfiguration in the robot’s width is possible, due to the scissor mechanism at the core of the robot’s body, which is driven by a lead screw motor. Panthera will perform locomotion and reconfiguration based on perception sensors feedback control proposed while using an Red Green Blue-D (RGB-D) camera. The proposed control scheme involves publishing robot kinematic parameters for reconfiguration during locomotion. Experiments were conducted in outdoor pavements to demonstrate the autonomous reconfiguration during locomotion to avoid pedestrians while complying with varying pavements widths in a real-world scenario.

Design and Analysis of Battery Box Lifter

The main objective of this project is to design and analyze the portable hydraulic scissor truck instead of manual pallet truck for the purpose of dropping and lifting battery box in AC Coaches to bring it outside for checking suspension/cradle of battery box for availability of all suspension bolts, signs of any cracks, corrosion, rusting and taking corrective action, if necessary. If suitable hydraulic cylinder with more power is used, this scissor lift can also be designed for heavy load purposes. This equipment will be simple to use. Frequent maintenance is not required for this equipment. In this paper we carried out detailed analysis of scissor mechanism members against bending and buckling failure and also focused on various design aspects and working of scissor mechanism and helpful to lifting and dropping of battery box without any failure with this scissor truck For existing practice the battery box dropping and lifting done by using manual pallet truck. It shows the design is unsafe handling, injury to employee and feel uncomfortable. It is very tedious for human being to lift a vehicle above from the ground. Even when a hydraulic jack is implemented, it requires manual work. In this era, every man in the world wants comfort and hence to relieve the problems faced by lifting and placing the battery box. Our project aims to reduce the manual work involved during the replacement of battery box instead of applying manual pallet truck. To validate our point and to reduce the above said difficulties faced, the design of hydraulic lift has been changed.