论文标题
使用磁场估算球插座的关节姿势
Ball-and-socket joint pose estimation using magnetic field
论文作者
论文摘要
Roboy 3.0是一种开源肌腱驱动的人形机器人，模仿了人体的肌肉骨骼系统。 Roboy 3.0正在作为远程机器人体（或机器人化身）开发，以使人类实现远程物理存在。人造肌肉和肌腱使其与3DOF颈部，肩膀和手腕紧密相似。 Roboy 3.0 3-DOF接头作为球插座接头实现。虽然工业界为1-DOF关节姿势感测提供了明确的解决方案，但球插槽接头却并非如此。在本文中，我们提出了一种自定义解决方案，以估计球插座接头的姿势。我们将一系列磁铁嵌入到球中，并将3D磁性传感器的阵列嵌入插座中。然后，我们根据磁场的变化，随着接头旋转，能够估计关节的方向。我们使用LSTM和贝叶斯过滤器（如DVBF）评估了两种神经网络方法的性能。结果表明，与LSTMS相比，为了达到相同的平方误差（MSE），DVBF需要更大的时间训练和高参数调整，而DVBF则更好地对传感器噪声进行了处理。两种方法均可在所有三个自由度合并的MSE下进行实时关节姿势估计为37 Hz，MSE约为0.03 rad。 LSTM模型被部署并用于Roboy 3.0的肩膀和颈部关节的关节姿势估计。软件实现和PCB设计是在https://github.com/roboy/ball_and_socket_estimator下开源的
Roboy 3.0 is an open-source tendon-driven humanoid robot that mimics the musculoskeletal system of the human body. Roboy 3.0 is being developed as a remote robotic body - or a robotic avatar - for humans to achieve remote physical presence. Artificial muscles and tendons allow it to closely resemble human morphology with 3-DoF neck, shoulders and wrists. Roboy 3.0 3-DoF joints are implemented as ball-and-socket joints. While industry provides a clear solution for 1-DoF joint pose sensing, it is not the case for the ball-and-socket joint type. In this paper we present a custom solution to estimate the pose of a ball-and-socket joint. We embed an array of magnets into the ball and an array of 3D magnetic sensors into the socket. We then, based on the changes in the magnetic field as the joint rotates, are able to estimate the orientation of the joint. We evaluate the performance of two neural network approaches using the LSTM and Bayesian-filter like DVBF. Results show that in order to achieve the same mean square error (MSE) DVBFs require significantly more time training and hyperparameter tuning compared to LSTMs, while DVBF cope with sensor noise better. Both methods are capable of real-time joint pose estimation at 37 Hz with MSE of around 0.03 rad for all three degrees of freedom combined. The LSTM model is deployed and used for joint pose estimation of Roboy 3.0's shoulder and neck joints. The software implementation and PCB designs are open-sourced under https://github.com/Roboy/ball_and_socket_estimator
