Impact Tool Motor Control with Adaptive Feedback Gains
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Solution Overview
Problem
Existing electric tools lack precise control over electric motors, particularly during impact operations, leading to inefficiencies and potential damage due to inadequate feedback control mechanisms.
Innovation Solution
An electric tool with a control unit that includes an impact detecting unit, which performs feedback control on the electric motor by changing target parameters such as control gains and upper limit values before and after an impact operation, allowing for precise control of the motor's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is performed with fixed target parameters during impact operations, then the control system remains simple, but the motor control precision deteriorates
Solution Approach 1:
The control system dynamically adjusts target parameters (control gains and upper limit values) based on the impact operation state detected by the impact detecting unit. During impact operations, the system switches to different target parameters than during non-impact operations, enabling precise motor control adapted to varying operational conditions without requiring an overly complex fixed-parameter system
Solution Approach 2:
The patent changes physical or operational parameters of the control system by adjusting control gains and upper limit values according to the impact operation state. This parameter adaptation allows the system to optimize motor control precision for different operational phases (impact vs. non-impact) while maintaining a relatively simple overall control architecture
2Productivity
If the impact mechanism operates with high impacting force, then the productivity increases, but the components suffer excessive wear and potential damage
Solution Approach 1:
The impact detecting unit provides feedback about the impact operation state to the control unit, which then adjusts motor control parameters accordingly. This feedback mechanism enables the system to monitor and control impacting force in real-time, maintaining high productivity during impact operations while preventing excessive force that would cause component wear or damage
Solution Approach 2:
The control system takes preliminary action by setting appropriate upper limit values for motor output before impact operations occur. By pre-configuring these limits and adjusting them based on detected impact states, the system prevents excessive force application that would lead to component damage, rather than reacting after damage occurs
Data Source
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AI summary
An object of the present disclosure is to provide an electric tool with the ability to control an electric motor more precisely. An electric tool (1) includes an electric motor (AC motor 15), an impact mechanism (17), and a control unit (4). The control unit (4) includes an impact detecting unit (49). The control unit (4) performs feedback control on an operation of the electric motor. In a following period after the impact detecting unit (49) has detected that the impact mechanism (17) has started an impact operation, the control unit (4) changes target parameters in a preceding period before the impact detecting unit (49) detects that the impact mechanism (17) has started the impact operation into different target parameters. The target parameters include a control gain of the feedback control.