Future space robotic mission need a set of integrated and inherently optimized interfaces for mechanical, data, electrical, and thermal connectivity that allow reliable, robust and multi-functional coupling of payload to robot manipulators, payload to other payload or client to server, in both orbital and planetary environments. With the increasing complexity of mission’s plans and tasks, a need for a standard, multifunctional, scalable, and modular interface arise. For all types, the main characteristics and functionalities are described and evaluated for orbital and planetary suitability. Modularity in space is one of the main issue that engineers and space mission planner have to face nowadays.
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Only one design with integrated thermal interface has been found, and it still needs further development. EM-Cube also is an interface with one mechanical connection type, but uses electromagnets and permanent magnets to enable the cubes to slide along their surface and to dock cubes with each other (An, 2008). The Self-assembling Modular Robot for Extreme Shapeshifting (SMORES) uses a magnetic connection by using permanent magnets (with 180° symmetry) and a docking key (used to reinforce a connection or undock) (Davey et al., 2012). These magnetic interfaces are non-mechanical and are considered semi-rigid. Denavit-Hartenberg parameters and their geometric meaning. 1) is built using of the Denavit-Hartenberg (DH) convention as specified in Siciliano et al. The transformation described by Equation (18) implies that, given the dual force (e.g., force and torque) applied on a body at location OX, the equivalent wrench about a different location OY can be computed by using a simple frame transformation operation, commonly known as the shifting law.
Analogously, the homogenous transformation matrix JTLi contains the DCM JRLi and position Jri.
However, the parameterization of the rotation using three parameters, e.g., Euler angle combinations, creates singularities, thus making the resulting DCM non-invertible. The use of DCM in developing the transformation matrices for the spacecraft-manipulator system is familiar and intuitive. Analogously, the homogenous transformation matrix JTLi contains the DCM JRLi and position Jri. 1), and by the position vectors of the centers-of-mass of the links, rj (0 ≤ j ≤ N). 1 ≤ i ≤ N. The origin ϱ1 of J1 as well as the directions of xJ1 and yJ1 can be selected as needed for a particular geometry. 1. Furthermore, for 2 ≤ i ≤ N, the origin ϱi of Ji is at the intersection of zJi and the common normal between zJi-1 and zJi. болки в кръста и таза при бременност
. Whenever zJi-1 and zJi are parallel, the common normal is uniquely defined and ϱi is selected for convenience (e.g., passing through the center-of-mass of the link i-1).
The main purpose of an interface in this context is to establish a rigid connection and transfer resources of various type (e.g., mechanical, electrical, data, thermal) between two units. Terrestrial examples of robotic connection interfaces are commonly seen in modular robotic systems, where homogeneous or heterogeneous modules interconnect to satisfy some functions, either mechanical, thermal, electrical, or computational. A comparison among existing interfaces in robotics and space is also presented, with respect to pre-defined mission scenario and requirements. In those three cases, a coordinate system centered at the center-of-mass of the orbiting spacecraft-manipulator system and having axes oriented in a fixed way with respect to an inertial frame (i.e., having zero absolute angular velocity) can be considered as equivalent to an inertial coordinate system for the description of the spacecraft-manipulator system motion. For the general case, the symbolic computation of c⋆ requires the derivatives of H⋆ with respect to each joint angle qk.
Furthermore, it is useful to define the following additional vectors.
For the calculation of these terms, the time derivatives of the joint and link direction-cosine matrices, JR˙Ji and JR˙Li are required. Modular platforms make the creation and the operation of large structures easy and also reduce manufacturing and maintenance costs, this is why they are being considered for large scale space operations. The following lemma recasts the identity operation on a dual quaternion in terms of the left and right dual quaternion multiplication operations. As for the time derivative above, the computation of the derivative of the generalized inertia matrix requires the separate computations shown in the following paragraphs. The base-spacecraft inertia matrix, manipulator inertia matrix, and the dynamic-coupling inertia matrix are thoroughly explained in the following subsections. Furthermore, it is useful to define the following additional vectors. Rotational orientation of an interface facilitates the docking procedure, for future space and planetary missions it is a useful attribute to have at least 4 docking orientations, such as in MTRAN, SINGO, PolyBot, AMAS, GENFA, iSSI, and the EMI.
SINGO, Telecube, PolyBot, AMAS, GENFA, ACOR, SWARM, Phoenix Tool, Phoenix Satlet, SSRMS LEE, iSSI, EMI, the Berthing and Docking Mechanism and the EM-Cube are all interfaces with redundancy elements. These examples are SINGO (Shen et al., 2009) with an androgynous clamp latch type, the Compliant-And-Self-Tightening (CAST) system (Khoshnevis et al., 2003) with a hook mechanism, the Cellular Robotic system (CEBOT) (Fukuda et al., 1989) with a peg-in-hole physical guidance system and hook latch mechanism, the Automatic Modular Assembly System (AMAS) (Sproewitz et al., 2008) with a hook mechanism, as well as the Berthing and Docking Mechanism of DEOS mission (Rank et al., 2011), and the semiandrogynous docking mechanisms (Olivieri and Francesconi, 2016). The mentioned systems are modular systems and have mechanical mechanism, which ensure a rigid connection once the robotic systems are docked with each other, highly important for robots containing modules with locomotive sub-functions.
Tentacles are composed of a double boom allocated at a chaser satellite’s middle plane and the tentacle is clamped by a hook device driven by a Linear Electro-Magnetic Actuator. A typical hook connector has been presented by Jørgensen et al. A conceptual design of a clamping mechanism for a grapple system for active space debris removal based on tentacles, has been developed and matured to a level with development and verification plan. The main advantage of this configuration is that it enables self-aligning, which is of fundamental importance for a large number of applications, and where additional connectors, requiring precise alignment, are involved. In a typical male-female interface arrangement, the clamp may be on the female side, but there are ways to produce a hermaphroditic clamp connection, where the clamps are the main points of contact on both faces. These designs in particular are part of an industry organized and well-funded effort to produce flight-ready designs, and so the complexity and refinement in the designers are very pronounced.
These designs allow for minimal adjustments to alignment during docking, particularly rotational alignment, and thus reduce fuel consumption and failure modes. болки в ставите при кучета
. The result is inserted into Equation (43), which is then solved for x¨0. It usually works by first having the male side of the connection coupled with the female counterpart; when the roto-lock engages, rotating around the center of interface, it tightens the female side or latches into groves on the male side (see Figure 1B). This concept is almost exclusively used with the Peg-in-hole system, and its main benefits are that it only involves one moving part, highly beneficial for space applications, that it can be developed in a genderless configuration (suitable for coupling identical interfaces), like in the iBoss project (Kortman et al., 2015), and that it is usually smaller compared to other configurations.