Robot Arm Filtering with Variable Cutoff for Vibration and Speed
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Solution Overview
Problem
Existing robot control technologies fail to effectively prioritize between positional accuracy and processing time while reflecting user intent, leading to inadequate operation performance.
Innovation Solution
A robot system with a band-stop and low-pass filter configuration that allows variable cutoff frequencies based on user input, prioritizing either vibration suppression or operating speed, ensuring appropriate position accuracy and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a low-pass filter with low cutoff frequency is applied to suppress vibration, then vibration suppression is improved, but operating speed deteriorates
Solution Approach 1:
The patent applies dynamics by making the cutoff frequency of the low-pass filter variable rather than fixed. The controller dynamically adjusts the cutoff frequency based on the robot's operational state - using lower cutoff frequencies during deceleration phases to suppress vibration, and higher cutoff frequencies during acceleration or high-speed operations to maintain operating speed. This dynamic adaptation resolves the contradiction between vibration suppression and operating speed maintenance.
2Speed
If a low-pass filter with high cutoff frequency is applied to maintain operating speed, then operating speed is improved, but vibration suppression deteriorates
Solution Approach 1:
The controller dynamically switches between high and low cutoff frequencies based on real-time operational conditions. During high-speed operations or acceleration phases, a high cutoff frequency is used to maintain operating speed. During deceleration phases where vibration becomes problematic, the cutoff frequency is lowered to suppress vibration. This dynamic switching strategy allows the system to optimize both operating speed and vibration suppression at different stages of motion.
3Ease of operation
If constant acceleration method is used to simplify control, then ease of operation is improved, but position accuracy deteriorates due to residual vibration
Solution Approach 1:
The patent employs feedback control by continuously monitoring the robot's operational state (acceleration, deceleration, position) and using this information to dynamically adjust the low-pass filter parameters. The controller detects when the robot is decelerating and automatically applies a low cutoff frequency to suppress residual vibration, thereby improving position accuracy while maintaining the simplicity of the constant acceleration control method.
Solution Approach 2:
The patent changes the parameters of the low-pass filter (specifically the cutoff frequency) based on the operational phase. During deceleration, the cutoff frequency is reduced to filter out vibration frequencies. During acceleration or constant velocity phases, the cutoff frequency is increased to minimize impact on operating speed. This parameter adaptation allows the system to achieve both control simplicity and position accuracy.
Data Source
AI summary
A robot system includes an arm, one or more motors that move the arm according to a drive signal, a controller that controls the one or more motors, and an input section. The controller includes one or more sets including a filtering section that filters a position command to generate a filtered command and a drive signal generator that generates the drive signal using the filtered command. The filtering section includes a band-stop filter and a low-pass filter having a variable cutoff frequency. The cutoff frequency is set to a first frequency when an instruction to prioritize an operating speed is received, and the cutoff frequency is set to a second frequency lower than the first frequency when an instruction to prioritize suppression of vibration out of the suppression of vibration of the arm and the operating speed of the arm is received.