External force observer for humanoid robots has been widely studied in the literature. However, most of the proposed approaches generally rely on information from six-axis force/torque sensors, which the small or medium-sized humanoid robots usually do not have. As a result, those approaches cannot be applied to this category of humanoid robots, which are widely used nowadays in education or research.In this paper, we propose a Kalman filter-based observer to estimate the three components of an external force applied in any direction and at an arbitrary point of the robot’s structure. The observer is simple to implement and can easily run in real time using the embedded processor of a small or medium-sized humanoid robot such as Nao or Darwin-OP. Moreover, the observer does not require any changes to the robot’s hardware, as it only uses measurements from the available force-sensing resistors (FSR) inserted under the feet of the humanoid robot and from the robot’s inertial measurement unit (IMU).The proposed observer was extensively validated on a Nao humanoid robot in both cases of standing still or walking while an external force was applied to the robot. In the conducted experiments, the observer successfully estimated the external force within a reasonable margin of error. Moreover, the experimental data and the MATLAB and C++/ROS implementations of the proposed observer are available as an open source package. https://goo.gl/VkhejY.

中文翻译：

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中小型人形机器人外力观测器

仿人机器人的外力观测器在文献中得到了广泛的研究。然而，大多数提出的方法通常依赖于来自六轴力/扭矩传感器的信息，而中小型人形机器人通常没有这些信息。因此，这些方法不能应用于如今广泛用于教育或研究的这类人形机器人。方向和机器人结构的任意点。观察者实现简单，可以使用Nao或Darwin-OP等中小型人形机器人的嵌入式处理器轻松实时运行。而且，观察者不需要对机器人的硬件做任何改动，因为它仅使用插入人形机器人脚下的可用力感应电阻器 (FSR) 和机器人的惯性测量单元 (IMU) 的测量值。所提出的观察者在 Nao 人形机器人的两种站立情况下都得到了广泛验证机器人在外力作用下静止或行走。在进行的实验中，观察者成功地在合理的误差范围内估计了外力。此外，所提出的观察者的实验数据和 MATLAB 和 C++/ROS 实现可作为开源包使用。https://goo.gl/VkhejY。所提出的观察者在 Nao 类人机器人上得到了广泛验证，无论是静止还是行走，同时对机器人施加外力。在进行的实验中，观察者成功地在合理的误差范围内估计了外力。此外，所提出的观察者的实验数据和 MATLAB 和 C++/ROS 实现可作为开源包使用。https://goo.gl/VkhejY。所提出的观察者在 Nao 类人机器人上得到了广泛验证，无论是静止还是行走，同时对机器人施加外力。在进行的实验中，观察者成功地在合理的误差范围内估计了外力。此外，所提出的观察者的实验数据和 MATLAB 和 C++/ROS 实现可作为开源包使用。https://goo.gl/VkhejY。