Power Tool Accessory Identification by Rotational Inertia

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Solution Overview

Problem

Existing power tools cannot distinguish between different working accessories, leading to suboptimal performance and limited functionality, as they are controlled by a single control program.

Innovation Solution

A power tool with a self-detection capability that estimates the rotational inertia of the motor in a pre-starting stage to identify the attached working accessory and control the motor according to a target control program specifically matched to the accessory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single control program is used for all working accessories, then the device complexity is reduced, but the adaptability and performance optimization for different accessories deteriorates

Engineering Contradiction:

Improvecontrol program complexityVSAvoidadaptability to different working accessories

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The control device changes control parameters (such as motor speed, torque, acceleration) based on the identified working accessory type. Different accessory types trigger different control parameter sets, allowing optimal performance for each accessory without requiring completely separate control programs.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system automatically identifies the attached working accessory through sensor detection and rotational inertia measurement, then autonomously selects and applies the appropriate control program without user intervention. This self-service capability eliminates manual configuration while achieving adaptability.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If different control programs are used for different working accessories, then the adaptability and performance are improved, but the device complexity increases

Engineering Contradiction:

Improveadaptability to different working accessoriesVSAvoidcontrol program complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system is segmented into modular components: accessory identification module, rotational inertia calculation module, and control program selection module. Each module performs a specific function, making the overall complex system manageable and maintainable through clear separation of concerns.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple control programs are pre-configured in the control device for different working accessory types. The system performs preliminary preparation by storing these programs and selecting the appropriate one based on accessory identification, avoiding the need for complex real-time control program generation.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If automatic accessory identification is implemented, then the adaptability is improved, but the measurement precision requirements and device complexity increase

Engineering Contradiction:

Improveautomatic accessory identification capabilityVSAvoidrotational inertia measurement precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system replaces complex mechanical identification methods with electrical measurement approaches. By measuring rotational inertia through electrical parameters during motor startup, the system achieves accessory identification without complex mechanical sensors or manual intervention.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Rotational inertia serves as an intermediary parameter that indirectly identifies the working accessory type. Instead of directly measuring accessory characteristics, the system measures the motor's rotational inertia, which varies based on the attached accessory, providing a reliable identification mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables the power tool to automatically identify and optimize the operation of different working accessories, enhancing their performance and functionality.

Implementation Method 1

when the motor is in a pre-starting stage, estimate the rotational inertia of the motor and identify the working accessory currently mounted to the mounting portion based on the rotational inertia

Methodology Applied

Scientific EffectRotational inertia: Inertia

Data Source

PatentUS20250070702A1Electric tool and control method

Publication Date: 2025.02.27 NANJING CHERVON IND

AI summary

A power tool includes a mounting portion for optionally mounting one working accessory of multiple working accessories; a motor configured to drive the working accessory mounted on the mounting portion; and a control device configured to control rotation of the motor according to a target control program matching the working accessory. The control device is configured to, when the motor is in a pre-starting stage, estimate rotational inertia of the motor and identify the working accessory currently mounted to the mounting portion based on the rotational inertia.