Quadrupedal manipulators require to be compliant when dealing with external forces during autonomous manipulation, tele-operation or physical human-robot interaction. This paper presents a whole-body controller that allows for the implementation of a Cartesian impedance control to coordinate tracking performance and desired compliance for the robot base and manipulator arm. The controller is formulated through an optimization problem using Quadratic Programming (QP) to impose a desired behavior for the system while satisfying friction cone constraints, unilateral force constraints, joint and torque limits. The presented strategy decouples the arm and the base of the platform, enforcing the behavior of a linear double-mass spring damper system, and allows to independently tune their inertia, stiffness and damping properties. The control architecture is validated through an extensive simulation study using the 90kg HyQ robot equipped with a 7-DoF manipulator arm. Simulation results show the impedance rendering performance when external forces are applied at the arm's end-effector. The paper presents results for full stance condition (all legs on the ground) and, for the first time, also shows how the impedance rendering is affected by the contact conditions during a dynamic gait.

翻译：四重操纵者在自主操作、远程操作或人体-机器人相互作用期间与外部力量打交道时,必须服从于四重操纵者的要求。本文件展示了全机控制器,允许实施全机控制器,以协调跟踪机器人基地和操纵器臂的性能和所需合规性能。控制器是通过一个优化问题来配制的,使用Quadratic编程(QP)来为系统强加一种理想的行为,同时满足摩擦锥体限制、单方面武力限制、联合和扭伤限制。提出的战略解除了平台的手臂和基底,强制执行了线性双质量弹跳系统的行为,并允许独立调节其惰性、僵硬性和阻力特性。控制结构通过使用配备了7DoF操纵器臂的90公斤HyQ机器人进行广泛的模拟研究得到验证。模拟结果显示,当外部力量在手臂的终端效应下应用时,其性能会受到阻碍。本文展示了完全定位状态的结果(所有双腿在地面上),并首次展示了阻力在动态条件下如何受到影响。