Power Tool Regulator Energy-Based Torque Control
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Solution Overview
Problem
Existing regulators, such as PID regulators, face challenges in efficiently tightening fasteners to a predetermined torque within a short time, leading to increased tool load, heat generation, and poor ergonomics due to fluctuating acceleration forces and current variations.
Innovation Solution
A regulator that utilizes energy contributions within the system to control motor torque and current, allowing for a smooth braking process to minimize energy consumption and maintain a stable torque, thereby optimizing the tightening process in terms of time, efficiency, and ergonomics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PID regulator is used to tighten fasteners to predetermined torque, then the torque can be regulated, but the tightening time increases and heat develops in the tool
Solution Approach 1:
The patent changes the control parameter from position-based PID control to energy-based control. By monitoring the energy consumed by the motor during tightening and comparing it to a predetermined energy value corresponding to the target torque, the system achieves precise torque control while minimizing tightening time. The regulator determines when to stop the motor based on energy consumption rather than traditional PID parameters.
2Measurement precision
If a PID regulator is used to tighten fasteners, then torque regulation is achieved, but the load and strain on the power tool increase
Solution Approach 1:
The patent converts the harmful effect of motor inertia and kinetic energy into a beneficial control mechanism. By using the energy consumed during motor operation as the control parameter, the system naturally accounts for inertial effects and kinetic energy variations. This energy-based approach smooths out load fluctuations and reduces strain on tool components, improving reliability while maintaining accurate torque regulation.
3Productivity
If high acceleration forces are used to tighten fasteners quickly, then productivity increases, but ergonomics for the operator deteriorates
Solution Approach 1:
The patent converts the operator's manual guidance input into a beneficial feedback signal for automated control. The system detects small manual guidance movements and uses them to modulate motor current, transforming what would be disruptive manual interference into a smooth control input. This allows high-speed automated tightening while maintaining excellent operator ergonomics and control.
4Measurement precision
If the motor is braked early to achieve target torque, then torque precision improves, but tightening time increases
Solution Approach 1:
The patent performs preliminary calculation of the required braking duration and magnitude before actual braking occurs. The regulator continuously monitors motor energy consumption and predicts when the target energy value will be reached, allowing the motor to maintain high speed as long as possible. The braking action is precisely timed and sized based on pre-calculated energy requirements, achieving both high torque accuracy and minimal braking time.
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
This approach reduces energy losses, minimizes deviations from the target torque, and improves tool endurance and operator ergonomics by maintaining a stable and low-level current profile during tightening, ensuring accurate and efficient fastening.
Implementation Method 1
By using the kinetic energy for tightening the fastener and to control the power tool using the current to the motor of the power tool
Implementation Method 2
By exploiting the kinetic energy of the motor 7 and gear 8, the motor energy is adjusted so that no excessive energy is used
Data Source
AI summary
A regulator for a power tool for tightening a fastener in order to unite two or more pieces into a joint. The regulator regulates the power tool when tightening the fastener such that the fastener is tightened to a predetermined target. The regulator calculates an output signal to the power tool, which output signal is based on the product of the torque exerted by the power tool on the fastener and the angle for turning the fastener about its axis. The output signal is used for tightening the fastener to the predetermined target. The regulator is also applicable to a power tool for a rivet joint.