A Vision-Based Referencing Procedure for Cable-Driven Parallel Manipulators

Abstract

In the last three decades, cable-driven parallel robots (CDPRs) have captured a growing attention in the robotics field. Indeed, they promise to bring automation in fields where it is not affirmed yet, granting ease of scaling and reconfigurability. For large-workspace cable robots, accuracy is an important issue. In this paper, a look-and-move procedure is proposed, based on a wireless camera, to refer the coordinate frame of the CDPR platform to another known coordinate frame. Two sample cases are studied and presented. In the first, the proposed vision-based system is employed to let the platform precisely attain its home position. In the second, the platform is referenced to an external coordinate frame, in order to accurately accomplish an assigned task. For both cases, experiments are successfully carried out.

Constant Distance and Orientation Following of an Unknown Surface with a Cable-Driven Parallel Robot

“…This adds to the complexity of profile-following tasks. Most of the research works focus on improving the CDPR model, especially regarding cable elasticity and sagging [1], [2], [3], [4], [5], [6], [7] but other approaches such as vision-based control have also been proposed to improve the precision of CDPRs [8], [9]. The robustness of trajectory planning and tracking for CDPRs was evaluated in [10].…”

Exit Point, Initial Length and Pose Self-calibration Method for Cable-Driven Parallel Robots

“…The second category is the external sensors, for example cameras [13], which can directly measure the position and orientation of the MP. In [14], a look-and-move calibration procedure is developed based on a wireless camera. A low-cost, and efficient calibration method using camera is described in [15] .…”

“…In [17], the robot calibration is carried out while the Cartesian coordinates of the exit points expressed in the moving-platform frame are supposed to be known. Some other contributions using multiple sensors have been made [14,15,18,19]. Self-calibrations, as the case in this work, are realised by the help of internal sensors [11].…”

Visual Servoing of Cable-Driven Parallel Robots with Tension Management

“…There are multiple ways to use a vision system for controlling CDPRs. A straightforward way is to use a camera mounted on the base to retrieve the MP pose [6]- [9], which avoids the need of the Direct Kinematic Model (DKM). For CDPRs with a large workspace, multiple cameras are usually required, e.g.…”