In the context of telehealth, robotic approaches have proven a valuable solution to in-person visits in remote areas, with decreased costs for patients and infection risks. In particular, in ultrasonography, robots have the potential to reproduce the skills required to acquire high-quality images while reducing the sonographer's physical efforts. In this paper, we address the control of the interaction of the probe with the patient's body, a critical aspect of ensuring safe and effective ultrasonography. We introduce a novel approach based on variable impedance control, allowing real-time optimisation of a compliant controller parameters during ultrasound procedures. This optimisation is formulated as a quadratic programming problem and incorporates physical constraints derived from viscoelastic parameter estimations. Safety and passivity constraints, including an energy tank, are also integrated to minimise potential risks during human-robot interaction. The proposed method's efficacy is demonstrated through experiments on a patient dummy torso, highlighting its potential for achieving safe behaviour and accurate force control during ultrasound procedures, even in cases of contact loss.

翻译：在远程医疗背景下，机器人技术已被证明是替代偏远地区患者面对面就诊的宝贵解决方案，能够降低患者成本和感染风险。特别是在超声检查中，机器人有潜力再现获取高质量图像所需的技能，同时减少超声医师的体力消耗。本文探讨了探头与患者身体交互的控制问题，这是确保安全有效超声检查的关键环节。我们提出了一种基于可变阻抗控制的新方法，可在超声检查过程中实时优化柔顺控制器的参数。该优化被表述为二次规划问题，并纳入了从粘弹性参数估计中推导出的物理约束。安全性和无源性约束（包括能量池）也被集成在内，以最小化人机交互过程中的潜在风险。通过在患者躯干模型上的实验验证了所提方法的有效性，结果表明即使在接触丢失的情况下，该方法也能实现超声检查过程中的安全行为和精确力控制。