Electric Power Tool Load-Adaptive Control for Precise Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Powerful power tools, such as heavy electric hammers, are difficult to manually operate due to vibration and tilting, leading to positioning errors and safety issues.
Innovation Solution
An electric power tool with a controller that maintains a first operating state by holding a physical quantity constant and switches to a second operating state when a load is detected, increasing power output when the load persists, and returns to the first state when the load decreases, using sensors to monitor current, torque, power rating, or PWM status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor operates at full power output, then the power tool can handle heavy loads effectively, but the tool experiences increased vibration and becomes difficult to position manually
Solution Approach 1:
The system dynamically adjusts the motor operating state based on real-time load detection. The controller monitors physical quantities (current, torque, power rating, or PWM status) and automatically transitions between first and second operating states, making the power output adaptive rather than static. This resolves the contradiction by providing full power only when needed while maintaining ease of operation during positioning.
Solution Approach 2:
The system implements feedback control by continuously monitoring physical quantities related to motor operation and load conditions. The controller uses this feedback to determine when to switch between operating states, ensuring the motor delivers appropriate power levels. This feedback mechanism allows the system to respond to actual operating conditions, preventing unnecessary full-power operation that causes vibration while ensuring adequate power when loads are applied.
2Power
If the motor operates at high power output continuously, then the tool can handle any load condition, but the tool lifespan is reduced due to excessive wear and heat
Solution Approach 1:
The system uses periodic load detection and state switching based on predefined thresholds and time periods. When load conditions meet specified criteria (delta in physical quantity exceeds threshold for a predetermined time), the system transitions to the second operating state; otherwise, it operates in the first state. This periodic assessment and adaptive switching reduces continuous high-power operation, thereby extending tool lifespan while maintaining adequate power availability.
3Ease of operation
If the motor operates at low power output, then the tool is easy to handle and position, but the tool cannot handle increased loads effectively
Solution Approach 1:
The system dynamically adjusts power output based on actual load conditions rather than maintaining a fixed low power state. The controller monitors physical quantities and automatically transitions to high power output when load conditions require it, resolving the contradiction by making power adaptive - low during positioning for ease of operation, high when loads are applied for effective performance.
Solution Approach 2:
The system performs preliminary load detection and assessment before transitioning to high power output. By monitoring physical quantities and evaluating whether load conditions meet predefined criteria, the system prepares to switch states in advance, ensuring smooth transitions from low to high power output when needed while maintaining ease of operation during the positioning phase.
Data Source
Figure 1~2a
Figure 2b
Figure 3a~3d
AI summary
An electric power tool comprises a motor, a controller configured to control the motor to operate in a first operating state by holding a first physical quantity related to the motor operation to be substantially constant, and a load detector configured to detect an increased load by measuring a second physical quantity different from the first physical quantity; wherein the controller is configured to control the motor to operate in a second operating state when a delta in the second physical quantity measured by the load detector rises above a pre-set threshold and remains above the pre-set threshold for a pre-defined period of time; wherein a power output of the motor in the second operating state is higher than a power output of the motor in the first operating state.