A Nonlinear Latching Filter to Remove Jitter From Movement Estimates for Prostheses
A Nonlinear Latching Filter to Remove Jitter From Movement Estimates for Prostheses
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DOI：
10.1109/tnsre.2020.3038706
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发表时间：
2020-11
影响因子：
4.9
通讯作者：
Jacob G. Nieveen;Mark R. Brinton;D. J. Warren;Senior Member;V. J. Mathews
中科院分区：
文献类型：
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作者：
Jacob G. Nieveen;Mark R. Brinton;D. J. Warren;Senior Member;V. J. Mathews
连续运动意图解码器对于精确控制手部和腕部假肢至关重要。生物信号中的噪声（例如，肌电信号或神经信号）可能导致这些类型的解码器的输出中的不期望的抖动。解码器输出端的低通滤波器（LPF）可有效降低抖动，但也会显著减慢预期的运动。本文介绍了一种替代方案，锁存滤波器（LF），一个递归的，非线性滤波器，提供平滑的小幅度抖动，但允许快速改变其输出响应大的输入变化。卡尔曼滤波器（KF）解码器的性能进行了比较，平滑与LF与KF解码器没有额外的平滑和KF解码器平滑与LPF。这三种算法进行了测试，在实时的目标持有和目标达到任务，从5个非截肢受试者记录的表面肌电图信号，和肌内肌电图和周围神经信号记录从截肢受试者。当与LPF相比时，LF在截肢者和非截肢者受试者在要求的位置保持手稳定并更快地实现运动目标的能力方面提供了统计学显著的改善。KF解码器与LF提供了一个统计学上显着的改善，在所有科目的能力，以保持假肢手稳定，只有略低的速度相比，未平滑的KF。
Continuous movement intent decoders are critical for precise control of hand and wrist prostheses. Noise in biological signals (e.g., myoelectric or neural signals) can lead to undesirable jitter in the output of these types of decoders. A low-pass filter (LPF) at the output of the decoder effectively reduces jitter, but also substantially slows intended movements. This paper introduces an alternative, the latching filter (LF), a recursive, nonlinear filter that provides smoothing of small-amplitude jitter but allows quick changes to its output in response to large input changes. The performance of a Kalman filter (KF) decoder smoothed with an LF is compared with that of both an KF decoder without an additional smoother and a KF decoder smoothed with a LPF. These three algorithms were tested in real-time on target holding and target reaching tasks using surface electromyographic signals recorded from 5 non-amputee subjects, and intramuscular electromyographic and peripheral neural signals recorded from an amputee subject. When compared with the LPF, the LF provided a statistically significant improvement in amputee and non-amputee subjects’ ability to hold the hand steady at requested positions and achieve movement goals faster. The KF decoder with LF provided a statistically significant improvement in all subjects’ ability to hold the prosthetic hand steady, with only slightly lower speeds, when compared to the unsmoothed KF.