论文标题
受摩擦锥约束的最佳控制腿部机器人
Optimal Control of Legged-Robots Subject to Friction Cone Constraints
论文作者
论文摘要
提出了层次控制结构，用于对腿部机器人进行节能控制，以受到各种线性/非线性不平等约束，例如库仑摩擦锥，单方面接触，执行器饱和度限制，并最大程度地减少关节执行器中的功率损失。控制公式可以将非线性摩擦锥约束纳入控制中，而无需求助于约束的常见线性近似或Slack变量的引入。引入了性能指标，该指标允许在找到最佳解决方案的情况下进行多个约束交易是不可行的。此外，基于投影的控制器不需要最小订单的动力学模型，因此允许切换触点对腿部机器人特别有吸引力。得出的约束惯性基质的基本特性与系统的一般惯性矩阵相似，随后将这些特性大量用于控制设计目的。以所有物理约束约束的最小（点）功率耗散的任务空间控制问题被转录为四次约束二次编程（QCQP），可以通过障碍方法解决。
A hierarchical control architecture is presented for energy-efficient control of legged robots subject to variety of linear/nonlinear inequality constraints such as Coulomb friction cones, switching unilateral contacts, actuator saturation limits, and yet minimizing the power losses in the joint actuators. The control formulation can incorporate the nonlinear friction cone constraints into the control without recourse to the common linear approximation of the constraints or introduction of slack variables. A performance metric is introduced that allows trading-off the multiple constraints when otherwise finding an optimal solution is not feasible. Moreover, the projection-based controller does not require the minimal-order dynamics model and hence allows switching contacts that is particularly appealing for legged robots. The fundamental properties of constrained inertia matrix derived are similar to those of general inertia matrix of the system and subsequently these properties are greatly exploited for control design purposes. The problem of task space control with minimum (point-wise) power dissipation subject to all physical constraints is transcribed into a quadratically constrained quadratic programming (QCQP) that can be solved by barrier methods.
