Electric Tool Motor Velocity Control for Torque Dispersion
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Solution Overview
Problem
Existing electric tool systems using electronic clutch control face challenges in maintaining user-friendliness due to motor inertia, which prevents effective control at high velocities and results in reduced work rate and increased work time, especially when trying to stop the motor quickly.
Innovation Solution
The electric tool system incorporates a controller that manages motor torque by setting a predetermined restriction value for the motor's velocity, preventing the torque from exceeding an upper limit and allowing the motor to slow down before stopping, thereby improving user-friendliness and reducing dispersion in fastening torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electronic clutch control is used to stop the motor when torque reaches the upper limit value, then the motor can be stopped effectively, but the motor inertia prevents effective control at high velocities resulting in reduced work rate and increased work time
Solution Approach 1:
The controller performs preliminary action by controlling the motor velocity to a predetermined restriction value before the torque reaches the upper limit value. This preliminary velocity control prepares the motor for quicker stopping and prevents the harmful effects of motor inertia from causing excessive work time, thereby resolving the contradiction between reliable stopping control and high work rate.
2Ease of operation
If the motor velocity is controlled to a predetermined restriction value before stopping, then the dispersion in fastening torque is reduced and user-friendliness is improved, but the control system becomes more complex
Solution Approach 1:
The controller implements feedback control by continuously monitoring the torque value and comparing it with the upper limit value. When the torque approaches the upper limit, the controller adjusts the motor velocity to the predetermined restriction value based on this feedback, ensuring consistent fastening torque and improved user-friendliness while managing system complexity through intelligent control algorithms.
3Device complexity
If traditional electronic clutch control is used at high motor velocities, then the control system is simpler, but the motor cannot be stopped effectively and work time increases
Solution Approach 1:
The controller dynamically adjusts the motor velocity based on the torque value and operating conditions. By making the velocity control adaptive and dynamic rather than static, the system can effectively stop the motor at high velocities while maintaining relatively simple control architecture, thereby reducing work time without significantly increasing device complexity.
Data Source
AI summary
An electric tool system includes: a motor; an output shaft to be coupled to a tip tool; a transmission mechanism that transmits motive power of the motor to the output shaft; an acquirer that acquires, based on a current flowing through the motor, a torque value related to output torque provided by the tip tool; and a controller that has a torque management mode in which the controller controls the motor in accordance with an operating command entered by a user through a trigger switch and prevents the torque value from exceeding an upper limit value. The controller controls, when finding a predetermined condition satisfied in the torque management mode, a velocity of the motor into a predetermined restriction value irrespective of a manipulative variable of the trigger switch. The predetermined condition includes a condition that the torque value reach a threshold value smaller than the upper limit value.