Piezoelectric Motor Downsizing for Robot End Effector
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Solution Overview
Problem
Existing robots face challenges in downsizing their end effectors and arm structures for precision work due to structural limitations.
Innovation Solution
The use of first and second piezoelectric motors with vibrators, where the distance between the rotation axis and vibrator is minimized in the second motor, allowing multiple vibrators along the rotation axis and placement closer to the distal end, enables a compact and efficient rotary driving mechanism in both the robot and end effector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional rotary drive sources are used in the end effector, then the end effector can perform rotary driving functions, but the end effector and robot arm cannot be downsized
Solution Approach 1:
The patent replaces conventional rotary drive sources with piezoelectric motors that utilize piezoelectric effects to generate vibratory motion, which is then converted to rotary motion through specially designed vibrators. This substitution enables significant downsizing of the end effector while maintaining rotary driving functionality, as piezoelectric motors have no rotating parts and can be made extremely compact.
Solution Approach 2:
The patent employs vibrators that convert linear piezoelectric vibrations into rotary motion by arranging piezoelectric elements in specific spatial configurations. By utilizing vibratory motion in multiple dimensions and converting it to rotary motion, the system achieves compact rotary driving without traditional rotary mechanisms, enabling end effector downsizing.
2Volume of moving object
If the distance between rotation axis and vibrator is reduced, then the piezoelectric motor size is reduced, but the torque transmission efficiency may be affected
Solution Approach 1:
The patent employs asymmetric vibrator designs where the mass distribution and geometric shape are intentionally made asymmetric relative to the rotation axis. This asymmetry creates effective torque generation from piezoelectric vibrations even with minimal distance between the rotation axis and vibrator, resolving the contradiction between compact size and torque transmission efficiency.
Solution Approach 2:
The patent optimizes the vibrational frequency, amplitude, and phase relationships of the piezoelectric elements to maximize torque generation despite the reduced lever arm distance. By carefully controlling these parameters, the system achieves sufficient torque transmission while maintaining extremely compact motor dimensions.
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 configuration allows for the downsizing of the end effector and robot arm, enabling them to perform precision tasks in narrow areas with improved maintenance and flexibility.
Implementation Method 1
a first piezoelectric motor and a second piezoelectric motor respectively having vibrators that transmit drive forces to a driven portion and performing rotary driving
Data Source
AI summary
A robot including a manipulator having a plurality of joints and a base supporting the manipulator, includes a first piezoelectric motor and a second piezoelectric motor respectively having vibrators that transmit drive forces to a driven portion and performing rotary driving, wherein a distance between a rotation axis and the vibrator is smaller in the second piezoelectric motor than in the first piezoelectric motor, a plurality of the vibrators are placed along rotation axis directions in the second piezoelectric motor, and the second piezoelectric motor is placed closer to a distal end side opposite to the base than the first piezoelectric motor.