Rapidly Deployable Cable-Driven Parallel Robots

可快速部署的电缆驱动并联机器人

• 批准号: RGPIN-2021-03294
• 负责人: Cardou, Philippe
• 金额: $ 1.97万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754419
• 关键词: Rapidly; Deployable; Cable; Driven; Parallel

Cable--driven parallel robots (CDPRs) consist of an end effector suspended by a number of cables. Each cable is wound onto a servo-actuated spool, which is rigidly attached to a fixed frame. The end-effector displacements are controlled by simultaneously winding or unwinding the cables on their respective spools. Our interest in CDPRs stems from four advantages they hold over classical rigid-link robots: large workspaces; low cost; high speeds and accelerations; portability and reconfigurability. In our opinion, this latter advantage, the portability and reconfigurability of CDPRs, has been relatively neglected in previous research. We believe that this could be significantly improved by solving three problems: (1-2) making the CDPR calibration fully autonomous (3) designing new spools that can be mounted on towers rather than buttressed structures and (4-5) quickly tracing and certifying their workspace. The hardware will not have to be rebuilt from scratch for each project, because a dynamically reconfigurable CDPR is available at the Laboratoire de robotique. In projects (1-2), we will devise a mathematical method that allows to identify the CDPR mechanical model without the prior estimate of its parameters required by current calibration methods. Measuring the dimensions of a newly deployed cable robot is time consuming and constitutes an important limitation to its portability. The proposed method will be demonstrated through the dynamically reconfigurable CDPR already available and by designing a new highly portable lightweight CDPR. Project (3) was established from the observation that current CDPRs resemble more gantry cranes than tower cranes. To minimise the CDPR structure, we want to attach its spools on towers free of large buttresses, stabilisers or tethers. We will achieve this objective by cancelling the moment induced at the base of the tower by the cable tension applied at its top. A moving counterweight driven by the winch and cable direction will be used to cancel the moment. We will demonstrate this concept on a two--degree--of-freedom cable--suspended parallel robot in the vertical plane. In projects (4-5), we wish to develop faster methods for tracing and certifying the wrench-feasible workspace of CDPRs. The fastest available methods for tracing the workspace are based on line search, following rays emanating from a point until they intersect the workspace surface. We will propose a method where a path is followed along the workspace surface by using a predictor-corrector scheme. This method should be faster, as every point predicted along the path will be close to the true workspace surface, ensuring a fast correction step. As this type of workspace tracing method is not guaranteed to find the whole workspace, we will also develop a certification method. This method will consist in a branch-and-prune algorithm in which the lower bounds are computed through convex relaxations.

绳索驱动并联机器人(CDPR)由一个末端执行器组成，末端执行器由多根绳索悬挂。每根电缆都缠绕在一个伺服驱动的线轴上，这个线轴牢固地固定在一个固定的框架上。通过同时缠绕或解开各自卷轴上的缆线来控制末端执行器的位移。我们对CDPR的兴趣源于它们与传统刚性连杆机器人相比具有的四个优势：工作空间大；成本低；速度和加速度高；便携性和可重构性。在我们看来，CDPR的后一种优势，即CDPR的可移植性和可重构性，在以往的研究中被相对忽视。我们认为，通过解决三个问题可以显著改善这一点：(1-2)使CDPR校准完全自主；(3)设计可安装在塔架上的新卷轴，而不是支撑结构；(4-5)快速跟踪和认证其工作空间。硬件不需要为每个项目从头开始重建，因为机器人实验室提供了可动态重新配置的CDPR。在项目(1-2)中，我们将设计一种数学方法，允许在不事先估计当前校准方法所需的参数的情况下识别CDPR力学模型。测量新部署的缆索机器人的尺寸非常耗时，并且对其便携性构成了重要限制。所提出的方法将通过已有的动态可重构CDPR和设计一种新的高度可移植的轻量级CDPR来进行演示。项目(3)是通过观察到目前的CDPR更像门式起重机而不是塔式起重机而建立的。为了最大限度地减少CDPR结构，我们希望将其线轴安装在没有大型扶壁、稳定器或系绳的塔上。我们将通过抵消塔顶施加的缆索张力在塔底产生的力矩来实现这一目标。由绞车和钢丝绳方向驱动的移动配重将被用来抵消力矩。我们将在垂直平面的两自由度缆索悬挂并联机器人上演示这一概念。在项目(4-5)中，我们希望开发更快的方法来追踪和认证CDPR的扳手可行的工作空间。跟踪工作空间的最快方法是基于线搜索，跟踪从一点发出的光线，直到它们与工作空间曲面相交。我们将提出一种方法，其中通过使用预测-校正方案来沿着工作空间表面跟踪路径。这种方法应该更快，因为沿路径预测的每个点都将接近真实的工作空间曲面，从而确保快速校正步骤。由于这种类型的工作空间跟踪方法不能保证找到整个工作空间，我们还将开发一种认证方法。这种方法将存在于分支修剪算法中，在该算法中，通过凸松弛来计算下界。