Passive transmission-based robotic devices are capable of providing motion guidance while ensuring user safety and engagement. To circumvent some of the drawbacks associated with steering continuously variable transmissions based on rolling contacts, we are exploring a class of discretely variable devices, based on brakes and hydrostatic transmissions. Previously available control methods for discretely variable devices were built on velocity fields and only developed to stabilize a 1D target manifold. For n-DOF devices, methods to stabilize target manifolds of dimension 1 to n-1 are of interest. In this paper we contribute constraint field methods that stabilize n-1 dimensional target manifolds while leaving the orthogonal subspace free to the control of the operator. We also contribute force-modulated SDOF velocity fields, which add between 1 and n-2 virtual DOF to the motion of devices whose physical constraints leave one DOF. Control performance is demonstrated in simulation for 3DOF devices capable of imposing 1D or 2D constraints and in experiment for 2DOF devices imposing 1D constraints. Our experimental apparatus features digital hydraulic transmissions that are easily configured for n-dimensional space and capable of imposing constraints of any dimension, thus motivating the contributed methods.

中文翻译：

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离散变量无源机器人设备的矢量场控制方法

基于被动传输的机器人设备能够提供运动指导，同时确保用户安全和参与。为了避免与基于滚动接触的转向无级变速器相关的一些缺点，我们正在探索一类基于制动器和静液压变速器的离散可变装置。以前可用于离散可变设备的控制方法建立在速度场上，并且仅开发用于稳定一维目标流形。对于 n-DOF 设备，稳定维度为 1 到 n-1 的目标流形的方法是令人感兴趣的。在本文中，我们贡献了约束场方法，这些方法可以稳定 n-1 维目标流形，同时让正交子空间不受操作员的控制。我们还贡献了力调制的单自由度速度场，它将 1 到 n-2 个虚拟自由度添加到物理约束留下一个自由度的设备的运动中。控制性能在能够施加一维或二维约束的 3DOF 设备的模拟和施加一维约束的 2DOF 设备的实验中得到证明。我们的实验装置具有数字液压传动装置，可轻松配置用于 n 维空间并能够施加任何维度的约束，从而激发所贡献的方法。