IMU-Guided Power Tool Motor Spin-Up for Faster Activation
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Solution Overview
Problem
Traditional power tools, such as flywheel-based cordless nailers, experience a significant delay in reaching full operating speed due to motor spin-up time, which affects user productivity and preference for faster activation like pneumatic nailers.
Innovation Solution
A control system that utilizes an inertial measurement unit (IMU) to detect a pickup motion, increasing the motor speed to a target speed without actuating the trigger, thereby eliminating the perceived delay and preparing the tool for immediate use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor spin-up time is reduced to eliminate delay, then the productivity and user satisfaction are improved, but the motor requires higher power consumption and generates more heat
Solution Approach 1:
The system performs preliminary action by detecting pickup motion through the IMU sensor and pre-spinning the motor to a target speed before the trigger is actuated. This prepares the motor in advance so that when the user activates the tool, the motor is already near operating speed, significantly reducing the perceived delay while maintaining reasonable power consumption during actual use.
2Loss of time
If the motor is pre-spun to full operating speed, then the activation delay is eliminated, but the battery life is reduced due to continuous power consumption
Solution Approach 1:
The system applies partial action by spinning the motor to a target speed that is less than the full operating speed. This partial spin-up reduces the remaining speed gap that needs to be covered after trigger actuation, thereby reducing the perceived delay without requiring continuous full-speed operation that would drain the battery excessively.
Solution Approach 2:
The system dynamically adjusts the motor speed based on detected usage conditions. When pickup motion is detected, the motor is spun to a target speed; when not in use, the motor remains at low or zero speed. This dynamic speed adjustment optimizes the balance between activation responsiveness and battery conservation.
3Speed
If the motor speed is increased to eliminate delay, then the responsiveness is improved, but the heat generation increases
Solution Approach 1:
The system performs preliminary motor spin-up to a target speed upon detecting pickup motion, preparing the motor in advance before actual activation. This reduces the duration of high-speed operation needed after trigger actuation, thereby reducing total heat generation while maintaining fast responsiveness.
Solution Approach 2:
The motor operates dynamically at different speeds based on system state: low speed or idle when not in use, target speed when pickup is detected, and full operating speed only briefly after trigger actuation. This dynamic operation minimizes the time spent at high speeds, reducing heat generation while maintaining performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces the perceived motor spin-up delay by detecting the user's intent to use the tool, allowing the motor to reach a target speed when the tool is picked up, thus minimizing the time needed to reach full operating speed upon activation.
Implementation Method 1
an inertial measurement unit (IMU) configured to output IMU data
Implementation Method 2
determine a first orientation vector based on the processed 3-axis acceleration data, determine a second orientation vector based on the processed 3-axis acceleration data
Data Source
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AI summary
Certain embodiments provide a power tool comprising a motor including a flywheel, an inertial measurement unit (IMU) configured to output IMU data, and a controller coupled to the motor and the IMU. The controller is configured to process the IMU data to generate processed IMU data, detect, based on the processed IMU data, whether the power tool has been moved in a pickup motion that is associated with an imminent use of the power tool, and increase a speed of the motor to a target speed in response to the detection.