A 46-channel Vector Stimulator with 50mV Worst-Case Common-Mode Artifact for Low-Latency Adaptive Closed-Loop Neuromodulation

2021 ◽  
Author(s):  
Arindam Mandal ◽  
Diego Pena ◽  
Rajesh Pamula ◽  
Karam Khateeb ◽  
Logan Murphy ◽  
...  
Keyword(s):  
Closed Loop ◽  
Low Latency ◽  
Worst Case ◽  
Common Mode

scholarly journals Physiological Artefacts and the Implications for Brain-Machine-Interface Design

2020 ◽  
Author(s):  
Majid Memarian Sorkhabi ◽  
Moaad Benjaber ◽  
Peter Brown ◽  
Timothy Denison
Keyword(s):  
Interface Design ◽  
Closed Loop ◽  
Brain Activity ◽  
Current Source ◽  
Cardiac Activity ◽  
Total System ◽  
Case Scenario ◽  
Worst Case ◽  
Common Mode ◽  
Source Dipole

AbstractThe accurate measurement of brain activity by Brain-Machine-Interfaces (BMI) and closed-loop Deep Brain Stimulators (DBS) is one of the most important steps in communicating between the brain and subsequent processing blocks. In conventional chest-mounted systems, frequently used in DBS, a significant amount of artifact can be induced in the sensing interface, often as a common-mode signal applied between the case and the sensing electrodes. Attenuating this common-mode signal can be a serious challenge in these systems due to finite commonmode-rejection-ratio (CMRR) capability in the interface. Emerging BMI and DBS devices are being developed which can mount on the skull. Mounting the system on the cranial region can potentially suppress these induced physiological signals by limiting the artifact amplitude. In this study, we model the effect of artifacts by focusing on cardiac activity, using a current-source dipole model in a torso-shaped volume conductor. Performing finite element simulation with the different DBS architectures, we estimate the ECG common mode artifacts for several device architectures. Using this model helps define the overall requirements for the total system CMRR to maintain resolution of brain activity. The results of the simulations estimate that the cardiac artifacts for skull-mounted systems will have a significantly lower effect than non-cranial systems that include the pectoral region. It is expected that with a pectoral mounted device, a minimum of 60-80 dB CMRR is required to suppress the ECG artifact, while in cranially-mounted devices, a 20 dB CMRR is sufficient, in the worst-case scenario. The methods used for estimating cardiac artifacts can be extended to other sources such as motion/muscle sources. The susceptibility of the device to artifacts has significant implications for the practical translation of closed-loop DBS and BMI, including the choice of biomarkers and the design requirements for insulators and lead systems.

scholarly journals Compact closed‐loop resonator filters with wide spurious free band and extended common‐mode noise suppression

2020 ◽  
Vol 14 (9) ◽  
pp. 860-866
Author(s):  
Arcesio Arbelaez ◽  
Jose‐Luis Olvera ◽  
Alonso Corona ◽  
Carlos Saavedra
Keyword(s):  
Closed Loop ◽  
Noise Suppression ◽  
Common Mode ◽  
Free Band ◽  
Resonator Filters

ON-LINE SUPPLY VOLTAGE SCALING BASED ON IN SITU DELAY MONITORING TO ADAPT FOR PVTA VARIATIONS

2012 ◽  
Vol 21 (08) ◽  
pp. 1240027 ◽  
Author(s):  
MARTIN WIRNSHOFER ◽  
NASIM POUR ARYAN ◽  
LEONHARD HEISS ◽  
DORIS SCHMITT-LANDSIEDEL ◽  
GEORG GEORGAKOS
Keyword(s):  
Closed Loop ◽  
Supply Voltage ◽  
Average Power ◽  
Voltage Scaling ◽  
Error Rates ◽  
Design Flow ◽  
Chain Model ◽  
Worst Case ◽  
On Line

The presented Pre-Error Adaptive Voltage Scaling (AVS) approach tunes the supply voltage of digital circuits dependent on the present Process, Voltage and Temperature variations as well as Aging (PVTA). By exploiting unused timing margin, produced by state-of-the-art worst-case designs, power consumption is minimized. Timing information of the circuit is obtained by in situ delay monitors (Pre-Error flip-flops), detecting late-arriving signals (pre-errors) in critical paths. Based on the occurrence of pre-errors, the voltage is adjusted by a low-overhead control unit connected to the on-chip voltage regulator. As the voltage is adapted during normal circuit operation (on-line), the randomness of the applied input pattern has to be considered. We developed a Markov chain model, based on transistor level simulations, to describe the resulting statistics of the closed-loop voltage control. With this model, the risk of overcritical voltage reductions and the effect of global and local variations on the closed-loop control can be analyzed. For an arithmetic circuit, synthesized in an industrial 65nm design-flow, an average power saving of 23% (including all overheads) is achieved for very low error rates below 1E-11.

Worst-Case Identification of Errors-in-Variables Models in Closed Loop

2011 ◽  
Vol 56 (4) ◽  
pp. 762-771 ◽  
Author(s):  
Li-Hui Geng ◽  
De-Yun Xiao ◽  
Tao Zhang ◽  
Jing-Yan Song
Keyword(s):  
Closed Loop ◽  
Errors In Variables ◽  
Worst Case ◽  
Case Identification

Finite Element Modeling and Tansfer Function Prediction of Ball-Screw Drive System

2010 ◽  
Vol 431-432 ◽  
pp. 225-228
Author(s):  
Li Hua Lu ◽  
Ying Chun Liang ◽  
Fu Li Yu ◽  
Bao Ku Su
Keyword(s):  
Finite Element ◽  
Closed Loop ◽  
Constraint Equation ◽  
Ball Screw ◽  
The Finite Element Method ◽  
Worst Case ◽  
Thrust Bearings ◽  
Screw Drive ◽  
Ball Screw Drive ◽  
Ball Screw Drives

The closed-loop performance of a ball-screw drive is usually limited by a resonance in which the carriage oscillates in the direction of motion as the screw undergoes longitudinal and torsional deformation. By means of the finite element method (FEM), a model of ball-screw system dynamics is presented by taking into account the distributed inertia of the screw and the compliance and damping of thrust bearings, nut and coupling. Transmission ratio is modeled using DOFs (degree of freedoms) constraint equation. The model is found to accurately predict the transfer function from motor torque to carriage position. Comparing the predicted responses with experiments performed on a pair of ball-screw drives, the resonance frequency is misestimated as much as 5% in the worst case.

scholarly journals Low-Latency Wireless Data Transfer for Motion Control

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Jeroen de Boeij ◽  
Maarten Haazen ◽  
Peter Smulders ◽  
Elena Lomonova
Keyword(s):  
Motion Control ◽  
Closed Loop ◽  
Data Transfer ◽  
Transmission Delay ◽  
Low Latency ◽  
Wireless Data ◽  
Wireless System ◽  
New Approach ◽  
Precision Motion ◽  
Better Than

This paper discusses a new approach for wireless motion control. Existing wireless techniques suffer from large closed loop delays of several milliseconds, which is unacceptable in precision motion systems. These large delays are mainly caused by the protocol used, since these are optimized for transferring large amounts of data, not to minimize transmission delay. A new protocol and wireless system are proposed that reduce the closed loop transmission delay to less than 300 microseconds. The system has been verified in a real control system, and measurements show the performance, which is more than ten times better than existing techniques.

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