Author: mtimmons

Maximum Thrust vs. Battery Voltage

Maximum Thrust vs. Battery Voltage

In a previous post we got the Ardupilot simulator stable running the linear-quadratic attitude controller, but we had a hack in-place for normalizing our body torque commands from Newton-meters to -1 to +1 for input to the Ardupilot motor sub-system. Purpose This post uses a test stand to measure maximum available thrust over a range …

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Gyroscope History: Lead Computing Gunsights

Gyroscope History: Lead Computing Gunsights

In this post we’ll dissect and simulate basic concepts embodied in early gyro instrumentation applications in combat gun sights. We’ll build a deeper understanding of gyro mechanics through this application of their first principle: output torque resulting from precession. We’ll learn some interesting history too. The basic problem to solve is this: when we fire …

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Motor-Prop Model Validation

Motor-Prop Model Validation

In a recent post we used the Tyto 1520 test stand to get at a maximum thrust available from our motor-prop system. We want that maximum thrust so we can normalize our LQ controller command output for the Ardupilot motor command as outlined here. The Tyto 1520 offers great value for under $200. While we …

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Paper Slitter-Rewinder Edge Control Retrofit

Paper Slitter-Rewinder Edge Control Retrofit

A relocated paper web processing machine requires previously unused edge position control sub-system redesign and deployment to production. This article series covers system evaluation, control scheme prototyping, and production form factor system completion to production go-live.

Image-Guided Neurosurgery Thesis

Image-Guided Neurosurgery Thesis

System Prototype developed for MIT graduate thesis sponsors Massachusetts General Hospital and Radionics, Inc. Independently formulated and funded master’s thesis at MIT. Chased lead from human factors lab to MGH surgeon who posed a problem statement. Created in-lab initial prototype, and secured funding. Completed pre-planning and camera tracking system. Thesis

Precision Agriculture: Vehicle Control Systems

Precision Agriculture: Vehicle Control Systems

3D Neurosurgical image navigation school work tuned me into navigation in general. GPS applications for agriculture drew me to Trimble, where we produced early market leaders in steering aids and automatic steering systems. My first win was a differential GPS receiver coded to drive a “lightbar” steering aid. User interface, multiple pattern options, and, “curve” …

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Precision Irrigation Remote Control System

Precision Irrigation Remote Control System

Precision agriculture work extends to fixed-asset monitoring and remote control with this after-market control kit compatible with a range of irrigation control cabinet brands. We took a dealer prototype proof-of-concept in-house to an architecture that combined an acquired company’s assets with a Trimble hardware suite. I drove the hardware design, and multi-brand install kit flexible …

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Enterprise Agriculture

Enterprise Agriculture

Fertilizer Delivery Worked with Dealer-partner on a Fertilizer trailer tracking and empty detection system for major south Florida supplier to our existing grower customer base. This design element was motivated by general work managing enterprise clients during this time (see below) The Supplier served Trimble clients and covered the dealer-partner’s region. My work spanned concept …

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Optical Telecomm Sensors and Controls

Optical Telecomm Sensors and Controls

I spent a few years in the fascinating world of optical telecommunications designing and building in-system an in-spectrum analyzer, tunable filter controller, and an InGaAs (indium gallium arsenide) pixel-array power monitor. This work offered many unique challenges and experiences with fascinating equipment, instrumentation, control system design, and DSP techniques incorporating phased-lock loops, sensor interface FPGA …

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Medical Devices

Medical Devices

Remote Patient Monitoring Led software design for Guidant (later Boston Scientific) first In-Home implantable pacemaker-defibrillator remote monitor. Coded the DSP radio link. Managed platform requirements and the software team. In-Body Ultrasonic Communication Link