Cable-Based Robotic Crane (CBRC): Design and Implementation of Overhead Traveling Cranes Based on Variable Radius Drums

Abstract

In this paper we present a new family of overhead travelling cranes based on variable radius drums, called Cable-Based Robotic Cranes (CBRCs). A Variable Radius Drum (VRD) is characterized by the variation of the spool radius along its profile. This kind of device is used, in this context, for the development of a cable-robot, which can support and move a load through a planar working area with just 2 degrees-of-freedom. Firstly, we present the kinematic analysis and the synthesis of the geometry of VRD profile. Then, the schema of a bidimensional horizontal moving mechanism, based on the VRD theory, and an experimental prototype of a three-dimensional CBRC are presented. The features of this wire-based overhead crane and an analysis of cables tensions are discussed. Finally, the performance of this mechanism is evaluated, demonstrating a deviation between the end-effector and the nominal planar surface of less than 1% throughout the whole working area.

Natural Motion for Energy Saving in Robotic and Mechatronic Systems

“…The mechanism consists of a linear spring connected to a cable wound around a non-circular spool. A non-circular spool (or variable radius drum) is characterized by the variation of the spool radius along its profile [66]. In References [60,61], the spring mechanism is attached to each actuated joint, with respect to which the linear spring behaves as a non-linear rotational spring with a described torque profile given by the shape of the spool (Figure 2).…”

Cable Failure Operation Strategy for a Rehabilitation Cable-Driven Robot

“…In this case, the robot is no longer redundant, since one cable is considered broken. Accordingly, there is only one feasible tension vector that satisfies Equation (15) and vector τ can be computed as τ = {2.29, 2.99, 3.19, 0, mg}. This new tension vector allows for maintaining the static equilibrium of the end-effector after a cable failure.…”

“…Hence, it is important to have a control tool that can be used in real time to estimate the feasible wrench and identify which cable tensions are needed to stop the end-effector in case of cable failure. Future works will investigate the possibility of applying the Wrench Exertion Capability to more complex CDPRs, as in [15].…”

A New Mechanism for Soft Landing in Robotic Space Exploration

“…Our approach in achieving a soft landing exploits a mechanism called Variable Radius Drum (VRD) modeled in 2016 by Seriani and Gallina [40] to perform the shaping of the elastic response of a set of linear compression springs in order to provide a constant-force deceleration on the payload. In particular, using the equations from [41], we synthesize a VRD-based mechanism to provide the shaped force to an imaginary 0.9-kg payload within the lander itself in order to mitigate the possible acceleration-induced damage during landing. In Table 1, an overview of the state of the art is illustrated, showing the context in which our proposed solution lies.…”

“…The use of cables can be beneficial to the exploration of space environments because of their lightness and intrinsic modularity [44]. The concept of VRD has seen various applications in the industry for kinematics shaping [41,45], energy efficient springs [43], weight compensation [46], actuation [47,48], and shock absorption [42].…”